PAPERmaking! Vol.6 No.1 2020

PAPERmaking!

The e-magazine for the Fibrous Forest Products Sector

Produced by:

The Paper Industry Technical Association

Volume 6 / Number 1 / 2020

PAPERmaking!

O THE PUBLISHERS U S S OF O PAPER TECHNOLOGY INTERNATIONAL FROM

Volume 6, Number 1, 2020

CONTENTS: FEATURE ARTICLES: 1. Paper Physics: Effect of micro deformations on strength and extensibility 2. Novel Products: Paper yarn as a textile fibre 3. Paper Chemistry: Spray edition of polysaccharides for strength enhancement 4. Water Treatment: Dynamic soft sensing of organic pollutants 5. Recycling: FWA’s and reduction of fluorescence in white recovered papers 6. Wood Panel: Novel wooden composites for panel-type furniture 7. Corrugated: Cardboard-based packaging as renewable building insulation 8. Sludge Ash: Use of paper sludge ash for novel water treatment applications 9. Energy: Specific Energy Consumption for improving energy efficiency 10. Agr-Pulping: Application of soda-AQ to pulping of okra stalks 11. Leadership: How to lead through a crisis 12. Motivation: 8 ways to keep remote employees motivated during crisis 13. Driving: Various tips to improve driving performance.

14. Video Conferencing: thirteen etiquette tips.

15. Presentations: How to ace a remote presentation.

SUPPLIERS NEWS SECTION: Products & Services:

Section 1 – PITA Corporate Members: ABB / ANDRITZ / VALMET Section 2 – Other Suppliers Machinery / Sensors, Testing & Analysis

DATA COMPILATION: Installations: Overview of equipment orders and installations since November 2019 Research Articles: Recent peer-reviewed articles from the technical paper press Technical Abstracts: Recent peer-reviewed articles from the general scientific press Events: Information on forthcoming courses / events / webinars

The Paper Industry Technical Association (PITA) is an independent organisation which operates for the general benefit of its members – both individual and corporate – dedicated to promoting and improving the technical and scientific knowledge of those working in the UK pulp and paper industry. Formed in 1960, it serves the Industry, both manufacturers and suppliers, by providing a forum for members to meet and network; it organises visits, conferences and training seminars that cover all aspects of papermaking science. It also publishes the prestigious journal Paper Technology International and the PITA Annual Review, both sent free to members, and a range of other technical publications which include conference proceedings and the acclaimed Essential Guide to Aqueous Coating.

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Contents

PAPERmaking!

O THE PUBLISHERS U S S OF O PAPER TECHNOLOGY INTERNATIONAL FROM

Volume 6, Number 1, 2020

Effect of mechanically induced micro deformations on extensibility and strength of individual softwood pulp fibers and sheets Jarmo Kouko, Marina Jajcinovic, Wolfgang Fischer, Annika Ketola, Ulrich Hirn, Elias Retulainen.

Tensile tests of individual bleached kraft pulp fibers and paper sheets of industrial origin were conducted in order to investigate the effect of refining and small-scale fiber deformations on the extensibility of fibers and paper. The shape of the tensile curves of most of the fibers was concave upward (i.e., increasing slope) and consisted of two or three phases suggesting that the fibrillar structure and disordered regions in the fiber wall were straightened out during straining. Only a few of the individual BSKP fiber tensile curves were apparently linear. Elongation of the individual kraft fibers varied from 8 to 32% and the average elongation was not increased by high consistency refining. Tensile test results of laboratory sheets made of the same BSKP pulp suggested that the fiber bonding not only governs paper strength, but also is highly relevant for the elongation of fiber networks. The key conclusion related to this investigation and freely dried sheets was that the increased network elongation and strength after refining is mainly due to increased inter-fiber bonding and a higher shrinkage tendency of the fiber network and not due to the increased elongation or strength of individual fibers.

Contact information: J. Kouko A. Ketola E. Retulainen VTT Technical Research Centre of Finland Ltd, Koivurannantie 1, 40400 Jyva¨skyla¨, Finland M. Jajcinovic W. Fischer U. Hirn Institut fu¨r Papier-, Zellstoff- und Fasertechnik, Graz University of Technology, Inffeldgasse 23, 8010 Graz, Austria. Also CD Laboratory for Fiber Swelling and Paper Performance, Inffeldgasse 23, 8010 Graz, Austria Cellulose (2019) 26:1995–2012 https://doi.org/10.1007/s10570-018-2163-y This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http:// creativecommons.org/licenses/by/4.0/)

The Paper Industry Technical Association (PITA) is an independent organisation which operates for the general benefit of its members – both individual and corporate – dedicated to promoting and improving the technical and scientific knowledge of those working in the UK pulp and paper industry. Formed in 1960, it serves the Industry, both manufacturers and suppliers, by providing a forum for members to meet and network; it organises visits, conferences and training seminars that cover all aspects of papermaking science. It also publishes the prestigious journal Paper Technology International and the PITA Annual Review, both sent free to members, and a range of other technical publications which include conference proceedings and the acclaimed Essential Guide to Aqueous Coating.

Page 1 of 19

Article 1 – Effect of Fibre Deformations on Strength

Cellulose (2019) 26:1995–2012 https://doi.org/10.1007/s10570-018-2163-y

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ORIGINAL RESEARCH

Effect of mechanically induced micro deformations on extensibility and strength of individual softwood pulp fibers and sheets Jarmo Kouko . Marina Jajcinovic . Wolfgang Fischer . Annika Ketola .

Ulrich Hirn . Elias Retulainen

Received: 12 July 2018 / Accepted: 26 November 2018 / Published online: 4 December 2018 Ó The Author(s) 2018

Abstract Tensile tests of individual bleached kraft pulp fibers and paper sheets of industrial origin were conducted in order to investigate the effect of refining and small-scale fiber deformations on the extensibility of fibers and paper. The shape of the tensile curves of most of the fibers was concave upward (i.e., increasing slope) and consisted of two or three phases suggesting that the fibrillar structure and disordered regions in the fiber wall were straightened out during straining. Only a few of the individual BSKP fiber tensile curves were apparently linear. Elongation of the individual kraft fibers varied from 8 to 32% and the average elongation

was not increased by high consistency refining.

Tensile test results of laboratory sheets made of the same BSKP pulp suggested that the fiber bonding not only governs paper strength, but also is highly relevant for the elongation of fiber networks. The key conclusion related to this investigation and freely dried sheets was that the increased network elongation and strength after refining is mainly due to increased inter-fiber bonding and a higher shrinkage tendency of the fiber network and not due to the increased elongation or strength of individual fibers.

Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10570-018-2163-y) contains supplementary material, which is available to authorized users.

J. Kouko (&) A. Ketola E. Retulainen VTT Technical Research Centre of Finland Ltd, Koivurannantie 1, 40400 Jyväskylä, Finland e-mail: jarmo.kouko@vtt.fi M. Jajcinovic W. Fischer U. Hirn Institut für Papier-, Zellstoff- und Fasertechnik, Graz University of Technology, Inffeldgasse 23, 8010 Graz, Austria M. Jajcinovic W. Fischer U. Hirn CD Laboratory for Fiber Swelling and Paper Performance, Inffeldgasse 23, 8010 Graz, Austria

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1996

Cellulose (2019) 26:1995–2012

Graphical abstract

Keywords Individual softwood pulp fiber Single fiber elongation Stress–strain curve Tensile testing Viscose fiber

Introduction Properties of individual pulp fibers play a pivotal role in the development of the mechanical properties of fiber networks and structures. Fiber strength determines the ultimate strength of paper and composite materials. However, the elongation potential of fiber networks is governed by the behavior of single fibers, inter-fiber bonding (Seth 2005) and the network properties (Vishtal and Retulainen 2014). Strength and extensibility of single fibers and the papermaking potential of fiber networks have been reviewed by Seth (2005), Lindström et al. (2005), and recently Vishtal and Retulainen (2014) and Hubbe (2014). High extensibility is a key material property for several paper packaging applications, e.g., paper sacks, paper cups or food trays. In this work, the effect of mechanical treatments on the load-elongation behavior of commercial bleached softwood kraft pulp (BSKP) fibers and the corresponding papers was studied in order to improve the extensibility of this type of materials.

Due to the small length and width (0.7–3 mm length, 15–50 lm width) handling, mounting, and mechanical testing of individual pulp fibers is complicated and laborious. Another major difficulty regarding quantitative analysis is the natural variability of wood fibers caused by variation between trees.

Furthermore there is variation related to location in the stem: early- and latewood (i.e., spring- and

123

summerwood), compression wood (in softwoods), tension wood (in hardwoods), and variability in relation to radial and height position in a wood log (Groom et al. 2002; Lundqvist 2002; Gierlinger and Wimmer 2004; Luostarinen 2012). Additionally, pulp fibers are damaged, twisted or fibrillated in during chipping, pulping, and bleaching operations (Mott et al. 1995; Mohlin et al. 1996). In order to obtain reliable statistics for the pulp fiber properties, a sufficient number of fibers have to be tested.

There are several studies on the tensile properties of pulp fibers (Leopold and McIntosh 1961; Jentzen 1964; Spiegelberg 1966; Hill 1967; Alexander et al.

1968; Hardacker and Brezinski 1973; Duncker and Nordman 1965; Page et al. 1972; Page and Seth 1980; Page and El-Hosseiny 1983; Groom et al. 2002; Jajcinovic et al. 2016). Typically, tensile strength and also elastic modulus are reported but strain at break is often disregarded. When stress–strain curves of individual restrained dried fibers are presented (Jayme 1959; Kallmes and Perez 1965a, b; Van den Akker et al. 1965; Duncker and Nordman 1965; Leopold 1966; Hardacker and Brezinski 1973; Groom et al.

2002; Mott et al. 2002), they are typically practically linear or slightly concave downward, with an elongation to break of about 2–6%. Significantly higher elongation values (* 20%) have been reported for Longleaf pine fibers cooked in laboratory conditions and dried under longitudinal compression (Dumbleton 1971), for commercial Southern pine kraft pulp fibers dried individually on a Teflon treated glass plate allowing drying shrinkage (Hardacker and Brezinski 1973), and for Loblolly pine fibers selected from the 5th annual ring at a low height of the tree (Groom et al.

2002; Mott et al. 2002).

Cellulose (2019) 26:1995–2012

Microfibril angle (MFA) of the S2 cell wall layer has been proven to be one of the most important factors influencing the mechanical properties of wood and pulp fibers (Page et al. 1972; Page and ElHosseiny 1983; Paavilainen 1993; Seth 2005; Long and Batchelor 2018). Page et al. (1972, 1977) used the mercury reflection technique in combination with a stereo-microscope for determining the fibril angle (MFA). Groom et al. (2002) used a confocal scanning laser microscope (CSLM) to determine the MFA of fiber specimens. Keunecke et al. (2008) used smallangle X-ray scattering and Wang et al. (2011) used an X-ray diffractometer to determine the MFA. Recently, Long and Batchelor (2018) measured bulk fibril angle using X-ray diffraction and the MFA of individual fibers using a confocal microscope and an analyzer crossed with polarization of the incident laser light.

Fibers with a high MFA are more extensible than those with a low MFA, although variation at the same MFA can still be large (Page et al. 1972; Page and ElHosseiny 1983; Borodulina et al. 2015; Long and Batchelor 2018). Thin-walled earlywood fibers are weaker and less stiff compared to thick-walled latewood fibers. Thin-walled earlywood Scots pine fibers have a higher MFA compared to thick-walled latewood Scots pine fibers, whereas in Norway spruce the opposite has been observed (Lichtenegger et al. 1999).

Drying under axial tension has been shown to decrease the MFA, i.e. increase the strength and reduce elongation (Jentzen 1964). Recently, also mechanosorptive creep rate has been measured and reported to correlate with the fibril angle (Dong et al. 2010; Olsson and Salmén 2014). Additionally, when fibril angles approach 45° the wood fibers do not exhibit mechano-sorptive creep due to the low degree of anisotropy of the elastic and swelling properties of such high fibril angle fibers.

Mechanical treatment of pulp has been shown to be an efficient way to improve the elongation of paper.

Three mechanisms are responsible for this. Firstly, improving the strength of the fiber–fiber bonding also increases the extensibility and strength of the paper.

Poorly bonded fiber networks fail before the full elongation potential of fibers is reached, whereas in well-bonded networks the fibers are under higher stress and are more strained before network failure.

Strong arguments have been presented that the nonlinearity and the viscoelastic properties of paper originate from within the fiber wall (Ebeling 1976;

1997

Page and Seth 1980). Secondly, the creation of dislocations and microcompressions of fibers introduced by refining (Dumbleton 1971; Hamad et al.

2012) has also been identified as a cause for increased paper elongation. The mechanism assumed here is that these deformations are, at least partly, pulled straight during loading of the network, which increases paper elongation under load. Small fiber deformations (microcompressions and dislocations) thus lead to a higher elongation before a break of the individual fibers. Hamad et al. (2012) estimated the changes in microcompressions during single fiber tensile testing by using Raman microscopy. According to Hornatowska (2009), areas with disorders of the fiber structure such as dislocations or microcompressions behaved more elastically. Alexander and Marton (1968) stated that when it comes to dislocations, refining affects the latewood fibers more strongly.

Watson and Dadswell (as cited by McIntosh and Uhrig 1968) pointed out that because of their more rigid nature, latewood fibers are damaged more during refining than the earlywood fibers. Thirdly, increased swelling and reduced axial stiffness have been named as causes of higher drying shrinkage and the consequent higher elongation of paper. However, influence of high consistency treatment on direct tensile properties of individual fibers is poorly known.

Several different fiber deformation types have been named and used in the literature, such as: curl, kinks, crimps, nodes, twists (axial and longitudinal), dislocations (longitudinal and transverse), microcompressions, misaligned zones, slip planes, and angular folds.

Some of the deformation types denote similar or identical deformation types, e.g. dislocations, slip plane, and misaligned zone. Node may mean a longitudinal compression where a fiber can bend and form a kink. Mohlin et al. (1996) and Page et al. (1985) have shown that the number of kinks, folds, twists or compressions correlated with the shape factor of pulp and they have an influence on tensile strength, tensile stiffness, stretch to break, and zero-span tensile strength of paper.

The objective of this study was to investigate the effect of small-scale deformations caused by mechanical treatment (refining) of pulps on the tensile behavior, and especially the extensibility of individual fibers and the papers made from those pulps. It is highly significant for the development of new fiberbased packaging products. This investigation was part

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1998 Table 1 Average length weighted fiber properties of the pulps and viscose fibers

Cellulose (2019) 26:1995–2012

Untreated

HC ? LC

LW fiber length of pulp (mm) (FiberMaster)

1.83

1.87

1.80

LW fiber length of pulp (mm) (Fiber Tester Plus)

1.73

1.66

1.22

LW fiber width of pulp (lm) (FiberMaster)

26.6

27.0

27.1

LW fiber width of pulp (lm) (Fiber Tester Plus)

27.4

25.5

24.2

Shape factor (%) (FiberMaster)

83.7

80.3

83.3

Form (shape factor) (%) (Fiber Tester Plus)

84.8

80.4

83.5

Kink per mm (mm-1) (Fiber Tester Plus)

of two larger research projects: ‘Tailored fibre–fibre interactions for boosted extensibility of bio-based fibre networks (ExtBioNet)’ supported by the Academy of Finland and the ‘Advanced Cellulose to Novel Products (ACel)’ program of the Finnish Bioeconomy Cluster CLIC Innovation. The objective of both projects was to improve the extensibility of the pulp fiber network for thermoforming applications.

Experimental Raw materials The raw material was a dried bleached softwood kraft pulp (BSKP), a mixture of spruce and pine, from a Nordic pulp mill. The BSKP was soaked overnight in tap water and then disintegrated for 30 min using a Valley beater without load. The BSKP was refined at 40% solids content (high consistency, HC treatment) using a wing defibrator (WD) exactly according to Khakalo et al. (2017a). WD is a high-intensity single stage batch wood chip refiner equipped with four rotating blades. Additional information on the refining conditions for HC treatment can be found in Zeng et al.

(2013). The HC treatment was followed by Valley beating (LC treatment) according to the standard procedure (SCAN-C 25:76). The same batch of BSKP is described in detail in Khakalo et al. (2017b) and was utilized in Khakalo et al. (2017a) and Kouko et al.

(2018). The SR numbers (ISO 5267-1) of the untreated and HC ? LC treated BSKPs were 12 and 25 and the WRV (ISO 23714) 1.08 g/g and 1.47 g/g, respectively. The SR number of the HC treated BSKP was approximately the same as untreated BSKP, because the influence of the HC treatment on SR number was minor as can be seen from Zeng et al. (2013) and Khakalo et al. (2017a). However, in both studies a

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HC

0.64

1.15

0.90

Viscose

5.54 17.2 88.7 0.014

clear influence of WD treatment on the average fiber properties of the pulp, e.g. shape factor and kinks, and the strength properties of hand sheets were observed.

In this study, the objective was to apply mechanical treatment methods of pulp fibers and chemical strength additives in order to maximize the strength and elongation of individual fibers and sheets. HC treatment of BSKP is known to increase both small and large-scale fiber deformation, whereas LC treatment straightens the fibers without significantly removing small-scale deformations (Seth 2005).

The fiber samples were selected from untreated, HC (high consistency) treated and HC ? LC (high ? low consistency)-treated pulps. Viscose fibers [Kelheim GmbH (DanufilÒ, 1.7 dTex and staple length 6 mm)] were used as a reference (see Bernt 2011 for more details). Fiber properties of the pulps were measured using the STFI FiberMaster and L&W Fiber Tester Plus (the fibers were measured in swollen state). The length weighted (LW) average fiber lengths and widths, as well as the shape factors, are presented in Table 1.

Paper samples The pulps were made into 60 g/m2 hand sheets according to EN ISO 5269-1. All hand sheets were wet pressed at 350 kPa for 5 ? 2 min with one exception, which is described later. Two drying methods were used to vary the shrinkage of the sheets: restrained drying after wet pressing according to the EN ISO 5269-1 and unrestrained drying between two forming wires that were supported by a grid and separated by a 5 mm thick rod. The elastic modulus and thus the strain to break of paper is known to vary considerably depending on whether the drying shrinkage is free or restrained, see, e.g., Mäkelä (2009) and Kouko and Retulainen (2018). Untreated and HC

Cellulose (2019) 26:1995–2012

1999

Fig. 1 Sample holder with 500 lm gap used for tensile testing

treated BSKP sheets were dried unrestrained and restrained, whereas HC ? LC BSKP sheets were only dried unrestrained.

Additionally, high pressure wet pressing and addition of strength chemicals were applied in order to improve bonding of the fibers. A few untreated BSKP sheets were wet pressed using 670 kPa pressure (instead of 350 kPa) before unrestrained drying.

Combination of 1.5% cationized starch, Cationic polyacrylamide (CPAM) 200 g/t and 5% Masuko micro-fibrillated cellulose (CMF) from VTT (E393HWM3) was added into untreated BSKP and the sheets were dried unrestrained and restrained. The starch Classic 135 was a potato-based wet-end starch with a degree of substitution of 0.035 from Chemigate.

The CPAM Fennopol K3400R with a molecular weight of 6–7 million g/mol and charge density of 1 meq/g was obtained from Kemira (Finland). The CMF was prepared from never-dried birch kraft pulp by mechanical disintegration. The dispersed pulp (1.7% consistency) was first pre-refined with a grinder (Supermasscolloider MKZA10-15 J, Masuko Sangyo Co., Japan) at 1500 rpm, followed by treatment with a fluidizer (Microfluidics M-7115-30, VTT, Espoo, Finland). The CMF was produced after three passes at an operating pressure of 1800 bar. No chemical modification was applied. The dry cationic starch was diluted in deionized water (conductivity \ 1 lS/m) to a final concentration of 1% and heated for 30 min at 90 °C under constant stirring. The dry CPAM was diluted in deionized water at 0.3% concentration. The solution was kept under constant stirring until fully dissolved and then further diluted to 0.01% for actual use. The influence of the addition of a similar CMF to a

BSKP pulp on the shrinkage, extensibility and strength of hand sheets is presented in Ketola et al. (2018).

Testing of the dry sheets took place at a temperature of 23 °C and at 50% relative humidity, using a strain rate of 10 mm/min (0.167%/s) in a Lloyd tensile tester, in accordance with ISO 5270:2012. The thickness and apparent sheet density of the dry paper were measured using ISO 534, and air-dry grammage using ISO 536.

Preparation and identification of single fibers Fibers for individual testing were prepared following the method described by Kappel et al. (2009). Dry pulp was dispersed and allowed to swell in water for at least 12 h. The fibers were disintegrated according to DIN EN ISO 5263-1. A highly dilute suspension with a consistency of 0.01% was prepared. Small drops of the suspension were placed on a piece of Teflon foil (40 mm 9 40 mm) and covered with another piece of Teflon foil. This sandwich was dried in a conventional sheet dryer for 45 min. The drying method used allowed shrinkage of the individual fibers. In order to perform single fiber tensile tests, the individual fibers were glued onto the sample holder (Fig. 1) using a two component epoxy resin (UHU PLUS ENDFEST). The sample holder used for the fiber tensile strength testing is described in Lorbach et al. (2014) and Jajcinovic et al. (2016). The gap in the sample holder was 0.5 mm. The span length is known to influence the strength (Hardacker 1970). After gluing of the individual fibers (Fig. 1), they were conditioned for at least 24 h prior to identification and testing to ensure the maximum holding strength of the resin and moisture equilibrium. The dry BSKP fibers were

123

2000

photographed before tensile testing and identified using a Leica DMLM microscope with 50 9 magnification and OptiMOS monochrome sensor camera from QImaging and using literature as a reference (Ilvessalo-Pläffli 1995).

The objective was to accept only pulp fibers without axial twisting and visible fractures to the tests. All fibers that were clearly identified as earlywood (springwood) fibers and the fibers with axial twisting, damage, or improper gluing were rejected. After tensile testing, cross-section images revealed that some of the tested fibers were thin-walled (earlywood) fibers, which was not possible to determine from the side-view image. Due to the laborious test procedure, the tensile results of the individual thin-walled and thick-walled fibers were grouped separately.

Determination of single fiber dimensions from microtome cross sections The cross sectional area (Across), fiber width (wf), and fiber thickness (tf) of single fibers were measured in the dry state from light microscope images, see Figs. 3b, 4b, 5b and 6b. After tensile testing, the fibers were glued onto paper tabs with a free end protruding out and embedded in a resin. Once the resin was cured, the fibers were cut with a Leica RM 2255 microtome with a cut thickness of 3 lm and imaged according to Lorbach et al. (2014). However, it was not possible to do the microtome analysis for all fibers due to the too short length of the broken pieces. In the case of successfully cut fibers, the images were binarized and the area analyzed using Matlab R2014b. From the images (presented in electronic supplementary material), it was possible to divide the tested untreated BSKP fibers into thick-walled and thin-walled fibers using the microtome photographs and a cross-sectional area of 190 lm2 as a limit.

Determination of single fiber width using fiber images Due to the too short length of the broken pieces, it was not possible to do the analysis for all fibers. The image analysis of width–length direction photographs, see Figs. 3a, 4a, 5a and 6a, was used for producing the fiber width data for all the measured fibers. The photographs were first changed to black and white (B&W) images and the fiber edges were slightly

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Cellulose (2019) 26:1995–2012

smoothed. Then image analysis software was used to measure the width of the fibers (pixel by pixel along the fiber length) and calculate the average fiber width.

A reference image of a ruler was used for defining the length scale. The averages of the calculated fiber widths are presented in Table 2.

Cleavage test of pulp fibers A cleavage test using hydrochloric acid (HCl) treatment developed by Ander et al. (2005, 2008) and slightly modified by Zeng et al. (2012) was used as an estimate for the number of fiber dislocations in the pulps and viscose fibers. The treatment presumably cuts the fibers at the dislocation areas, which have higher accessibility to the acid and can be considered as weak points in fibers. The arithmetic (AR) fiber lengths that were utilized in the calculation of cleavage index were measured using the STFI FiberMaster after setting the lower length limit of fibers to 44 from 200 lm. The cleavage results are presented in Table 3.

Single fiber tensile testing The single fiber tensile testing was performed using the fiber bond tester at TU Graz (Fischer et al. 2012; Lorbach et al. 2014; Jajcinovic et al. 2016). Off-set force was measured prior to the test and then a minor preliminary loading was applied to fiber. A displacement measurement system (shown in Fig. 2) was attached to the fiber bond tester in order to measure load-elongation data of the single fiber tensile tests.

The displacement of the tension support was measured using a laser displacement sensor (Micro-epsilon OptoNCDT LD 1605-10, with a resolution of 3 lm).

The displacement data was recorded using a National Instruments data logger system. The velocity of the moveable support of the fiber bond tester turned out to be very stable within the measurement accuracy of the laser sensor and therefore the linear fit of each measured displacement as a function of time was used in order to decrease the noise of the displacement data.

The load data recorded by the fiber bond tester was complemented by the displacement data as a function of time in the data analysis afterwards. Both data were measured at 1 kHz frequency.

Sample holder mounting was performed as described by Lorbach et al. (2014) and Jajcinovic

235 ± 37

1.79 ± 0.36

19.7 ± 2.8

9.1 ± 1.4

5

33.0 ± 3.9

7.3 ± 1.5

56 ± 14

86 ± 13

280 ± 30

9.9 ± 1.4

5

840 ± 130

6.5 ± 1.5

93 ± 29

0.84 ± 0.27

17.7 ± 3.8

3.9 ± 1.3

7

37.8 ± 3.4

2.5 ± 0.7

23 ± 8

73 ± 22

130 ± 20

4.1 ± 1.2

5

610 ± 150

5.4 ± 2.2

Breaking force (mN)

Slope of force (N)

Strain at break (%)

Work to break (lJ)

Tensile test repeats

Fiber width (lm)

Tensile strength (kN/m)

Tangential stiffness (kN/ m)

Breaking length (km)a

Cross section area (lm2)

Fiber thickness (lm)

Cross-section repeats

Tensile strength (MPa)

Tangential modulus (GPa)

6.0 ± 1.3

730 ± 120

10

6.8 ± 2.0

200 ± 50

76 ± 23

36 ± 12

4.5 ± 1. 6

35.8 ± 2.8

12

6.0 ± 1.8

18.5 ± 2.5

1.24 ± 0.35

152 ± 47

Untreated average

6.8 ± 2.3

710 ± 100

5

4.1 ± 0.6

120 ± 20

85 ± 19

31 ± 13

3.2 ± 1.0

33.5 ± 5.0

8

3.5 ± 0.8

14.5 ± 3.9

1.00 ± 0.30

103 ± 23

HC treated thin-walled

7.2 ± 0.6b

660 ± 100b

3

8.1 ± 2.2

260 ± 20

68 ± 12

47 ± 29

4.3 ± 2.2

41 ± 14

2

3.5 ± 0.4

18 ± 16

1.8 ± 0.5

170 ± 30

HC treated thick-walled

7.7 ± 1.4b

640 ± 310b

630 ± 140 6.3 ± 1.8

2

5.3 ± 1.0

143 ± 2

66 ± 20

32 ± 10

2.8 ± 1.4

35.0 ± 9.8

5

2.6 ± 1.5

12.1 ± 3.9

1.10 ± 0.38

92 ± 28

HC ? LC treated thinwalled

8

5.9 ± 1.7

180 ± 50

63 ± 15

34 ± 11

3.3 ± 0.9

34.7 ± 4.5

11

3.6 ± 0.9

14.6 ± 3.8

1.13 ± 0.31

111 ± 26

HC treated average

5.2 ± 0.8

640 ± 120

7

7.9 ± 1.5

230 ± 30

65 ± 12

32 ± 6

4.0 ± 0.8

36.9 ± 4.7

7

6.3 ± 2.4

20.6 ± 5.8

1.17 ± 0.18

145 ± 26

HC ? LC treated thick-walled

5.5 ± 1.1

600 ± 110

9

7.3 ± 1.3

210 ± 30

60 ± 12

32 ± 5

3.5 ± 0.8

36.1 ± 4.7

12

4.8 ± 1.8

16.9 ± 4.4

1.14 ± 0.18

123 ± 24

HC ? LC treated average

2.6 ± 0.7b

310 ± 30b

8

7.9 ± 0.8

136 ± 10

31.4 ± 2.7

21 ± 5b

2.4 ± 0.2b

17.2 ± 1.2

12

4.2 ± 0.8

34.3 ± 5.4

0.36 ± 0.08

41.9 ± 3.6

Viscose

Due to the low number of BSKP fiber repeats and missing identification images of the tested individual viscose fibers, the value is a ratio of the average breaking force and the average cross-section area. The cross-section repeats were used for the 95% confidence level. The other values are ratios of average of breaking force of an individual fiber divided by the cross-section area of the same fiber

b

a The density of the fiber-wall used was 1000 kg/m3 adapted from Yiannos (1964) and Janes (1992). Breaking length was reported in order to improve comparability with classical articles related to individual pulp fibers

Untreated thick-walled

Untreated thin-walled

Table 2 Average tensile properties and 95% confidence intervals of the individual BSKP and viscose fibers

Cellulose (2019) 26:1995–2012 2001

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2002

Cellulose (2019) 26:1995–2012

Table 3 Fiber cleavage of BSK pulps and a viscose fiber suspension Untreated

HC treated

HC ? LC treated

Viscose

LW fiber length of pulp (mm)

1.83

1.87

1.80

5.54

AR fiber length of pulp (mm)

0.63

0.64

0.58

2.07

AR fiber length of HCl-treated (mm) Cleavage (per fiber)

0.32 1.01

0.24 1.57

0.26 1.21

0.72 1.95

Cleavage index (arithmetic) (mm-1)

1.58

2.50

2.08

0.94

LW length weighted, AR arithmetic mean

Fig. 2 Schematic image of the fiber bond tester with the laser displacement detection system

et al. (2016). The sample holder was placed under a light microscope, which was equipped with a digital camera (Fischer et al. 2012) and a computer monitor.

The tensile test was recorded with the imaging system, which enabled rejection of the tests in which gluing failed. The fibers were strained until break at 1 lm/s elongation speed (0.2%/s strain rate). The initial part of the force-strain curve was not recorded due to pretensioning of the fiber before the test. The initial strain that corresponded to the initial force was calculated using the initial slope (initial tangential modulus) of the force–elongation curve. All tests were performed in a climate room at 23 °C temperature and 50% relative humidity.

The primary data obtained from the single fiber tensile test were load and displacement data. Tensile strength (rf) in MPa units (Eq. 1) corresponding to the break load (Fbreak) was calculated using the measured fiber cross-sectional area (Across) of each fiber. rf ¼

Fbreak Across

Ef ¼

Mf Across

ð2Þ

Results ð1Þ

As the fibers exhibit non-linear stress–strain behavior, the tangential stiffness and tangential modulus values were chosen to present the maximum slope of the tensile curve of the individual fiber. Tangential

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stiffness and modulus were calculated as the maximum slope of the load-strain curve of a single fiber divided by the width or the cross-directional area (Across), respectively. Tangential slopes, covering all stress–strain data until breaking, were calculated by applying a moving average slope over a constant strain range of 0.6%. The resulting tangential slope was an average at the region of the highest slope. The maximum of the slope on the load-strain curve of a single fiber was defined as force tangent modulus and here denoted simply by Mf. In this investigation, the tangential modulus (Ef) (Eq. 2) of a single fiber was obtained by dividing the Mf by the fiber crosssectional area (Across).

Characteristic images of the studied fibers Figures 3, 4, 5 and 6 present photograph examples of the tested fibers: sub-figures denoted (a) present length–width direction and sub-figures denoted

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Fig. 3 Untreated bleached softwood kraft fiber (#14): a visible dislocations and microcompressions, b collapsed cross-section of this thick-walled BSKP fiber. Width 33.4 lm, thickness 9.35 lm, cross-section area 276 lm2, breaking force 300 mN

Fig. 4 HC treated bleached softwood kraft fiber (#6): a external fibrils and a possible longitudinal dislocation, b collapsed crosssection of this relatively thin-walled BSKP fiber. Width 30.3 lm, thickness 4.7 lm, cross-section area 140 lm2, breaking force 87 mN

Fig. 5 HC ? LC treated bleached softwood kraft fiber (#3): a external fibrils and longitudinal dislocations and microcompressions, b collapsed cross-section of thick-walled BSKP fiber.

Width 33.2 lm, thickness 9.3 lm, cross-section area 294 lm2, breaking force 121 mN

(b) present cross-section images of the fibers. The microscope images of the fiber cross-sections showed that the lumen of all studied BSKP fibers was completely collapsed, whereas the viscose fibers did not have a lumen. The images of the other tested fibers are presented in the electronic supplementary materials S1-S4. A major finding from the individual fiber images was that the untreated BSKP fibers already had a significant number of dislocations.

Characteristic dimensions of the individual fibers Characterization of fiber cross-sectional properties (thickness, cross-section area and collapse) is generally difficult using only the fiber width. However, inspecting cross-section area and fiber thickness reveals that a cross-section area of 190 lm2 approximately divides the fibers into thin- and thick-wall classes (see Figures in supplementary material S1).

Accordingly, fibers with a cross-sectional area greater

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Fig. 6 Viscose fiber: a smooth and straight structure, b cross-section

Fig. 7 Tensile test of untreated BSKP fiber: a the fiber mounted in the tester before the test, b the tested fiber after the test

than 190 lm2 were classified as thick-walled fibers.

The average dimensions of the investigated individual fibers are presented in Table 3. The number of repeats was low for some classes, but the validity of the classification can be verified from the images supplied in the electronic supplementary material S1-S3.

Illustration of single fiber tensile test The tensile test of individual untreated BSKP fiber is described in Fig. 7. Figure 7a, b present the fiber mounted in the tester before and after the test. The force-strain curve of the individual untreated BSKP fiber was concave upwards, i.e., the slope increased as a function of strain. The breaking force of the individual fiber was 160 mN, which was close to the reported value for latewood fiber of softwood kraft pulp (192 mN and 206 mN for Scots pine and Norway spruce respectively, see Table 1 in the Supplementary material S1). The strain at break of the fiber was * 20%, which was high compared to the reported values for similar softwood pulp fiber (see Table 1). Side and cross-section microscope images and the force strain curves of all measured softwood fibers are presented in the electronic supplementary materials S1-S3.

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Average tensile properties of the tested individual BSKP fibers are presented in Table 2 and Fig. 8a, b.

The untreated, HC and HC ? LC treated BSKP fibers were classified as thin-walled, thick-walled and average (containing the two previous) groups using the cross-section images and areas. The number of repeats was low for some classes (e.g., HC treated thickwalled BSKP fiber). However, the relevance of the classification can be verified from the electronic supplementary materials S1-S3.

Thick-walled fibers versus thin-walled fibers Strain at break, breaking force, slope of force, and work to break of thick-walled fibers were significantly higher compared to the respective values of thinwalled fibers, which is according to expectations. HC and HC ? LC treatment decreased the breaking force of thick-walled fibers and did not affect the average breaking force of thin-walled BSKP fibers. Also, the observed reduction in breaking force due to the mechanical treatment is an expected result. There are clear differences between the tensile properties of thick-walled and thin-walled fibers.

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Fig. 8 a Breaking force over breaking strain and b slope of force over work to break with 95% confidence intervals plotted from the data in Table 2. The arrows show the influence of increasing mechanical treatment

Fiber elongation The high elongation values obtained for the BSKP fibers are higher that the most results presented in the literature. However, these fibers were from industrial pulp and gone through harsher treatments than laboratory processed pulps. Additionally the BSKP was made of chips from younger trees originating from thinnings that typically have higher fibril angle fibers (Groom et al. 2002). Elongation at break of thickwalled fibers was not significantly changed by the mechanical treatments, only the variance grew.

On the other hand, strain at break of thin-walled fibers decreased from the original 17.7% value to 14.5% and 12.1% due to the HC and HC ? LC treatments, respectively. The microscope photographs (see electronic supplementary material S1-S3) show that the investigated untreated BSKP fibers had a significant amount of small-scale deformations, which was slightly unexpected. Elongation of the viscose fiber, at 34.3%, was significantly higher compared to the BSKP fibers. Unexpectedly, the individual BSKP fiber elongation was not improved after the mechanical treatments.

Fiber tangential stiffness The tangential moduli of average BSKP fibers (containing thin- and thick-walled fibers) were in quite a narrow range from 5.5 to 6.3 GPa, but the values were also only 30–50% of the values presented from the literature in Table 1 in the supplementary material S1.

The mechanical HC treatment seemed to improve the

tangential modulus of thin- and thick-walled fibers (Table 2). However, the subsequent mechanical LC treatment reduced the tangential moduli of the thickwalled BSKP fibers, whereas the tangential moduli of the thin-walled BSKP fibers were slightly improved.

Microfibril angle (MFA) has been reported to dictate the elastic moduli of thin-walled (presumably earlywood) and thick-walled (presumably latewood) fibers (Schniewind 1966; Borodulina et al. 2015). Therefore, the investigated fibers may also have contained varied microfibril angles. Tangential modulus of the viscose fibers was 2.6 GPa, which was less than half that of the BSKP fibers. Unexpectedly, the influence of mechanical treatment on BSKP fibers’ tangential stiffness was small.

Individual fiber strength The HC and HC ? LC treatments decreased the tensile strength of BSKP pulp fibers on average, but the decrease concentrated on the thick-walled fibers, whereas strength changes of thin-walled fibers were within the 95% confidence intervals. Tensile strength in MPa units (force scaled with the cross-section area) of the BSKP fibers varied from 600 to 840 MPa, which is comparable to the results obtained in other studies (Hardacker and Brezinski 1973; Duncker and Nordman 1965; Page et al. 1972; Groom et al. 2002). The origin of the fiber strength is the strength of natural cellulose I polymer in the cell wall. A few estimates, varying from 297 to 800 MPa, have been given for the strength of crystalline and amorphous cellulose I polymer (Zeng et al. 2013; Lundahl et al. 2016), but on

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the other hand the strength of cellulose should probably be greater than the strength of BSKP fiber.

The tensile strength (310 MPa) of the viscose fibers, which are formed from cellulose II polymer chains, was less than half of that of the BSKP fibers. However, according to Bledzki and Gassan (1999), the mechanical properties of the man-made cellulosic fibers depend on their structure on different levels, and the tensile strength of viscose fibers has been shown to be strongly influenced by the length of molecules and straining in the manufacturing process. The lower tangential stiffness and the higher plasticity of viscose fibers, in respect to the BSKP fibers (shown in Fig. 10a–d), are some of the probable reason for the higher elongation and lower strength. The BSKP fibers contained some visible small-scale deformation and because of the removed lignin and hemicellulose (from the inner cell walls S1 and S2), their fiber-wall was possibly more porous than that of viscose fiber.

The small-scale deformations in the BSKP fibers did not seem to have any role for the strength in comparison to the structurally more homogeneous viscose fibers. As expected, a clear decrease in BSKP fiber strength was observed due to the mechanical treatments. On the other hand, the observed decrease in work to break (i.e. toughness) due to the mechanical treatment on BSKP was unexpected.

Cleavage of fibers A cleavage test using HCl treatment was used to estimate the number of fiber defects (Ander et al.

2005, 2008; Zeng et al. 2012). The HCl treatment mainly cuts the fibers at the dislocation areas, which can be considered as weak points in the fibers. The high consistency (HC) treatment of BSKP increased the cleavage and the LC treatment reduced the cleavage, as presented in Table 3. Both breaking force and elongation of the BSKP fibers formed a linear relation with negative slope as a function of cleavage index and with each other as shown in Fig. 9.

This suggests that both, fiber strength and fiber extensibility decrease with increasing mechanical treatment due to fiber damage. Additionally, the results indicate that the cleavage test may be a useful indirect method of estimating the influence of mechanical treatments on the strength and elongation of individual pulp fibers. Surprisingly, the viscose fibers showed several cleavages per fiber. However,

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Fig. 9 Breaking force and strain at break of the single BSKP fibers as a function of cleavage index of the pulps with 95% confidence intervals

the number of cleavages per length-unit in viscose fiber was lower compared to BSKP. Results indicate that viscose fibers are less homogenous than expected and may also exhibit defects. Also the mechanically untreated BSKP fibers had a significant number of cleavages per fiber.

Stress–strain curves of the fibers Stress–strain curves of the individual fibers are presented in Fig. 10a–d. Stress–strain curves of thick-walled fibers are presented in red and thinwalled in light blue. The markers with the 95% confidence intervals present average values of thickwalled, thin-walled, and all fibers according to Table 3. All force-strain curves of the individual fibers are presented in the electronic supplementary material S1-S4.

The tensile curves of the individual untreated BSKP fibers (Fig. 10a) were either smoothly and bi-linearly concave upward, apparently linear, or slightly concave downward, but none of them were highly concave downward, which is a typical shape for a tensile curve of paper (see Fig. 11a, b). The larger parts of the tensile curves were formed from two or even three phases that were mostly slightly concave upward.

Increasing slopes may indicate the presence of dislocations or other fiber deformations, which were pulled straight during tensile testing. The large variation between the single BSKP fiber stress–strain curves in terms of shape, in addition to the variation of elongation from 10 to 32%, can also be regarded as an important finding. The single fiber tensile curves

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Fig. 10 Stress–strain curves the tested fibers: a unrefined BSKP, b HC refined BSKP, c HC ? LC refined BSKP, d viscose

Fig. 11 Stress–strain curves of the tested BSKP hand sheets with restrained (a) and unrestrained drying (b). PFI 2000 rev. curves of the same BSKP from courtesy of Khakalo (additional information can be found from Khakalo et al. 2017a)

presented in the literature have typically been apparently linear or slightly concave downward (Kallmes and Perez 1965a, b; Van den Akker et al. 1965; Hardacker and Brezinski 1973; Groom et al. 2002, Mott et al. 2002), whereas the concave upward shape has been especially rare. In summary, unexpectedly

only a few of the individual BSKP fiber tensile curves were apparently linear and elongation range from 3 to 6% was absent, which is the typical elongation in the classical literature references reviewed. Unexpectedly, in this work, none of the individual BSKP fiber

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tensile curves were similar to the typical concave downward shape of a paper sheet.

The shape of the stress–strain curve of the viscose fibers also varied considerably, but to a much smaller extent than the pulp fibers (Fig. 10d). Tensile curves of viscose fibers typically consisted of three phases, i.e., an initial phase with steep slope was followed by a concave downward or concave upward phase and the last phase was concave downward. The strain at break of the viscose fibers varied from 20 to 50%, which was larger than expected. However, the variation of breaking force of viscose fibers was clearly smaller than that of the BSKP fibers. The relatively small variation of the breaking force of viscose fibers compared to BSKP fibers may be caused by the less heterogeneous cross-section area and the smaller number of defects.

Tensile properties of fiber networks Tensile tests were performed for both BSKP sheets dried under restraint and without restraint. The tensile test results are presented in Table 4 and the stress– strain curves in Fig. 11a, b. There was a large difference in the tensile stiffness and elongation at break values between the restrained and unrestrained dried sheets. This can be contributed to the difference in drying shrinkage.

Unrefined pulps gave the lowest strength and elongation at break values. Increased inter-fiber bonding by application of starch and cellulose microfibrils (CMF) and utilization of higher wet pressing pressure of the unrefined pulp improved elongation and tensile strength significantly and close to those of the HC refined pulps, which had approximately only 1 percentage point higher elongation.

However, increasing the number and area of fiber contacts by increasing the wet pressing pressure may be connected to water removal and is therefore limited. Applying LC refining to HC refined pulp increased both strength and elongation further. LC refining is known to make the fibers more straight and increase fiber swelling and subsequent shrinkage (Zeng et al. 2012, 2013).

The HC ? LC treatment in combination with unrestrained drying yielded the best elongation of 9.3% and tensile strength of 30 MPa of the studied BSKP samples, whereas in the case of individual fibers, the untreated BSKP fibers, on average, yielded

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the best results. For unrestrained drying the stress– strain curves indicate that the increase in strain is more due to an increase in bonding and less to dislocations and other fiber deformations. Unexpectedly, the results show that fiber bonding has an important role not only in determining the strength but also the elongation of fiber networks, which is in accordance with Seth (2005) and its references. In other words, a large increase in elongation can be reached only by strengthening fiber–fiber bonding (as demonstrated by the sheets with starch and CMF). Also, LC refining with 2000 revolutions in the PFI mill raised sheet extensibility to levels similar to HC and HC ? LC treatment in the case of both drying methods (unrestrained and restrained). This is untypical, as HC refining usually results in higher elongation at break (see e.g. West 1964).

The results suggest that HC refining can have a small positive effect on the elongation of paper but not on the elongation at break of single fibers. This apparent contradiction may be due to the fact that the stress individual fibers are subjected to in paper is, on average, much lower than their fracture stress. Paper fracture is determined by factors related to the development of stress concentrations that trigger the final failure in the fiber network. Nevertheless, the results indicate that microcompressions and ultimate strain at break of individual fibers may play a smaller role in sheet extensibility than has been previously believed.

The result show that high elongation of paper can be promoted by enabling shrinkage of the fiber network and securing high bonding ability of fibers.

Additionally, unrestrained drying seems to be much more effective tool for increasing paper extensibility than the fiber deformations caused by mechanical treatment. As a summary, unrestrained drying of BSKP fiber sheets in combination with increased fiber bond strength may be a promising approach for increasing paper extensibility.

Conclusions The tensile tests of individual fibers and paper sheets from bleached kraft pulp containing Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) were conducted in order to investigate the effect of small-

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Table 4 Average tensile properties and 95% confidence intervals of the BSKP sheets Untreated BSKP restrained

Untreated BSKP unrestrained

HC BSKP restrained

HC BSKP unrestrained

HC ? LC Untreated BSKP BSKP, unrestrained starch, CMF restrained

Untreated BSKP, starch, CMF unrestrained

Untreated BSKP 6.7 kPa wet pressing unrestrained

Tensile strength (kN/m)

1.65 ± 0.04

1.05 ± 0.06

2.11 ± 0.02

1.90 ± 0.74

3.54 ± 0.15

2.53 ± 0.10

2.36 ± 0.28

1.42 ± 0.08

Tensile strength (MPa)

13.6 ± 0.5

6.4 ± 0.2

19.0 ± 0.2

15.6 ± 0.6

30.0 ± 1.8

21.0 ± 0.8

17.5 ± 2.1

12.3 ± 0.7

Tensile index (Nm/g)

25.2 ± 0.9

15.2 ± 0.5

33.2 ± 0.4

27.5 ± 1.1

53.1 ± 2.3

40.6 ± 1.5

37.2 ± 4.2

24.6 ± 1.4

Tensile stiffness (kN/m)

270 ± 30

140 ± 40

289 ± 9

147 ± 16

129 ± 6

244 ± 19

137 ± 7.0

140 ± 6

Tensile modulus (GPa)

2.21 ± 0.11

0.86 ± 0.04

2.60 ± 0.08

1.21 ± 0.13

1.09 ± 0.03

2.03 ± 0.16

1.02 ± 0.05

1.21 ± 0.06

Strain at break (%)

2.12 ± 0.18

3.02 ± 0.18

4.31 ± 0.18

7.78 ± 0.21

9.25 ± 0.26

3.65 ± 0.30

6.2 ± 1.1

4.76 ± 0.18

Work to break (mJ)

39.5 ± 4.8

35.7 ± 3.1

103.6 ± 5.1

157.7 ± 8.9

291 ± 24

94.3 ± 9.3

154 ± 34

71.4 ± 5.2

Tensile test repeats

10

10

10

10

5

10

10

10

Sample thickness (lm)

121

163

111

122

118

120

135

115

Sample width (mm)

15

15

15

15

15

15

15

15

Grammage (g/m2)

65.5

68.9

63.6

69.1

66.6

62.2

63.3

57.5

Density (kg/m3)

541

423

573

566

564

518

469

500

Cross section area (mm2)

1.82

2.45

1.67

1.83

1.77

1.80

2.03

1.73

Breaking length (kma)

2.57 ± 0.09

1.55 ± 0.05

3.38 ± 0.04

2.81 ± 0.11

5.42 ± 0.33

4.14 ± 0.16

3.80 ± 0.45

2.51 ± 0.14

a

Breaking length values were reported in order to have improved comparability to classical articles related to individual pulp fibers

scale deformations caused by mechanical treatment (refining) on tensile behavior.

The measured strength and elongation of individual BSKP fibers ranged from 200 to 1100 MPa, and from 8 to 32%, respectively. Only a few of the individual BSKP fiber tensile curves were apparently linear.

More often the slope of the stress strain-curves increased with straining which behavior could be related to the straightening of disordered regions in the fiber wall. None of the individual BSKP fiber tensile curves was similar to the typical concave downward shape of paper sheet.

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The individual BSKP fiber elongation was not improved by the HC refining and a decrease in strength was observed. The influence of mechanical treatment on fiber tangential stiffness was small. The effects of the refining seemed to correlate with the number of dislocations (measured using HCl cleavage test) in fibers. With increasing number of dislocations both the average breaking stress and strain decreased. The mechanically untreated BSKP fibers already had a high number of dislocations based on the microscope images and HCl cleavage test. High consistency refining introduced additional dislocations, but low consistency refining seemed to be able heal some of them. There were clear differences between the tensile properties of thick-walled and thin-walled fibers. Also viscose fibers showed considerable variation and nonhomogeneity based on their stress strain-behavior and number of HCl induced fiber cleavages.

Comparison of the tensile tests of individual fibers and paper suggest that only a part of the elongation potential of individual fibers can be utilized in the elongation of paper and the fiber bonding governs not only the strength but also the elongation of fiber networks. Elongation of paper can be promoted by securing a high bonding ability of fibers and enabling shrinkage of fiber network. HC refining increased kinks and decreased the shape factor of the pulps and therefore had a major influence on the strength properties of the sheets, yet had only a minor influence on individual fibers. The results indicate that microcompressions and individual fiber extensibility play a smaller role in sheet extensibility than has been assumed. Unrestrained drying of BSKP fiber sheets in combination with increased fiber bond strength seemed to be a promising approach for increasing the extensibility of paper.

The key conclusion related to this investigation was that the increased network elongation was created by two factors. First, increased bonding improved paper strength and thus increased the strain to break. Second, the role of free shrinkage was again shown to be pivotal for sheet extensibility. Single fiber extensibility was not critical and seemed not to limit the extensibility of the paper.

Acknowledgments Open access funding provided by Technical Research Centre of Finland (VTT). This work has been funded by the ExtBioNet project supported by the Academy of Finland, the ACel program of the Finnish Bioeconomy Cluster CLIC Innovation and Association of

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Cellulose (2019) 26:1995–2012 European Fibre and Paper Research Organizations (EFPRO).

Funding by the Academy of Finland, the Finnish Funding Agency for Technology and Innovation (TEKES) and the Association of European Fibre and Paper Research Organizations (EFPRO) is gratefully acknowledged. Also the financial support for the CD Laboratory from the Austrian Federal Ministry of Science, Research and Economy and the National Foundation for Research, Technology and Development is gratefully acknowledged.

Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http:// creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

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PAPERmaking!

O THE PUBLISHERS U S S OF O PAPER TECHNOLOGY INTERNATIONAL FROM

Volume 6, Number 1, 2020

Manufacture and physical properties of the denim fabrics using Hanji paper yarn as weft yarn Tae Young Park and MyoungǦOk Kim. This study aims to develop the Hanji denim fabric with Hanji combination yarn or with the Hanji paper yarn and core spun yarn in a 1:1 ratio as a weft. For the weft yarn, chemical indigo and natural indigo dyestuffs were used. The study developed four kinds of Hanji paper yarns and eight kinds of Hanji denim fabrics. In addition, the study tested the properties of the developed Hanji paper yarns, Hanji denim fabrics, and existing denim fabrics. In regard to the physical properties of yarns, the Hanji paper yarn showed a lower breaking stress but a relatively high breaking strain, and it remained a stable structure with no surface fluff.

The Hanji combination yarn improved the weaving ability and had a stable structure form. In the resulting physical properties of the developed Hanji denim fabrics, they had a low apparent specific gravity, stability in dimensional change in washing and drying, a higher chance of commercialization in colorfastness to washing, medium stretchability, a similar drying velocity, and a fast absorption velocity compared to the existing denim fabrics. The study suggests that the Hanji denim fabrics are the good candidate materials for summer product development, since generally the Hanji denim fabrics have cool characteristics with the excellent absorption velocity, drying velocity, and low specific gravity.

Contact information: Tae Young Park, Howon University, Gunsan, South Korea.

MyoungǦOk Kim, University of Cincinnati, Cincinnati, USA. Park and Kim Fash Text (2018) 5:26 https://doi.org/10.1186/s40691-018-0140-6 This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creat iveco mmons .org/licen ses/by/4.0/).

The Paper Industry Technical Association (PITA) is an independent organisation which operates for the general benefit of its members – both individual and corporate – dedicated to promoting and improving the technical and scientific knowledge of those working in the UK pulp and paper industry. Formed in 1960, it serves the Industry, both manufacturers and suppliers, by providing a forum for members to meet and network; it organises visits, conferences and training seminars that cover all aspects of papermaking science. It also publishes the prestigious journal Paper Technology International and the PITA Annual Review, both sent free to members, and a range of other technical publications which include conference proceedings and the acclaimed Essential Guide to Aqueous Coating.

Page 1 of 14

Article 2 – Paper as a Textile Fibre

Park and Kim Fash Text (2018) 5:26 https://doi.org/10.1186/s40691-018-0140-6

Open Access

RESEARCH

Manufacture and physical properties of the denim fabrics using Hanji paper yarn as weft yarn Tae Young Park1 and Myoung-Ok Kim2*

*Correspondence: kim2mo@ucmail.uc.edu 2 University of Cincinnati, Cincinnati, USA Full list of author information is available at the end of the article

Abstract This study aims to develop the Hanji denim fabric with Hanji combination yarn or with the Hanji paper yarn and core spun yarn in a 1:1 ratio as a weft. For the weft yarn, chemical indigo and natural indigo dyestuffs were used. The study developed four kinds of Hanji paper yarns and eight kinds of Hanji denim fabrics. In addition, the study tested the properties of the developed Hanji paper yarns, Hanji denim fabrics, and existing denim fabrics. In regard to the physical properties of yarns, the Hanji paper yarn showed a lower breaking stress but a relatively high breaking strain, and it remained a stable structure with no surface fluff. The Hanji combination yarn improved the weaving ability and had a stable structure form. In the resulting physical properties of the developed Hanji denim fabrics, they had a low apparent specific gravity, stability in dimensional change in washing and drying, a higher chance of commercialization in colorfastness to washing, medium stretchability, a similar drying velocity, and a fast absorption velocity compared to the existing denim fabrics. The study suggests that the Hanji denim fabrics are the good candidate materials for summer product development, since generally the Hanji denim fabrics have cool characteristics with the excellent absorption velocity, drying velocity, and low specific gravity.

Keywords: Hanji paper yarn, Combination yarn, Hanji denim fabrics, Physical properties

Introduction A denim fabric is defined as a 100% woven cotton or union cloth with the ratios of 2:1 or 3:1 twill tissue using a warp, 7–20 Ne of cotton yarn (indigo vat dyeing), and the weft, unbleached yarn of 10–15 Ne. A surface of the denim fabric shows a blue color while the inside color shows a white color family only. Recently, the blue series production has been complimented by other colors with weaving patterns becoming more varied. Presently, the denim fabric is not limited to denim jean pants but also is widely used among those of all ages and genders of adult wear and children’s wear (Kim et al. 2009). In addition, the denim fabric is used in various other applications.

Human skin has an ability to stretch greatly with body movements. Generally, a wearer also expects to see the same attitude from their clothing (Ozdil 2008). However, the denim fabric is wrinkled since it does not have stretchable fiber component. It is a heavy

© The Author(s) 2018. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Park and Kim Fash Text (2018) 5:26

weight fabric compared to other woven fabrics. Instead of using the unbleached weft roll, one way to give successful stretchability to the denim fabric as a way to prevent wrinkles, is by the use of cotton yarn and spandex yarn by turns or, a second way, is by using a cotton/polyester blended spun yarn. However, even though the denim fabric that used cotton yarn and spandex yarn by turns has a relatively good stretchability, there have been issues due to the denim fabric’s uneven surface because the spandex yarn is of a fine sized yarn compared to the cotton yarn. In addition, in the case of the cotton/polyester blended spun yarn, it has been found that stretch and fabric lightweight improvement is needed to meet consumers’ needs. Recently, a core spun yarn is used as the weft yarn in order to give the denim fabric stretch (Ozdil 2008). The core spun yarn has stretchability with a feel of cotton because it has spandex as its core yarn and it is wrapped by cotton yarn.

Since the denim fabric is stiff and the color of indigo blue fades over time, without an application of finishing methods by either conventional industrial washing or new laser fading, it is not easy to achieve high quality denim wear (Juciene et al. 2006; Kan and Wong 2011; Khedher et al. 2011). In the world today, the premium denim fabric’s dye has been known as a dye that gradually and slightly fades with repeated washings and with a dehydration process. Also, there is need for comfort with softer touch, a lighter weight, and stretch to this premium fabric. With this trend, recently, there has been a development of functional denim fabrics. For example, in Japan in 2015, a paper denim fabric has been developed and used as the premium denim fabric (Park and Lee 2016).

This denim fabric has received attention as it introduces the need for lightweight with improved comfort by using a cotton yarn (indigo rope-dyeing) as the warp, and the Japanese paper yarn as the weft. The Japanese paper denim fabric is proper for denim jean pants and/or shirts worn in warm summer months. However, problems exist with wrinkles due to the fabric’s high rigidity and low stretchability of the paper yarn. In addition, there are consumers who want to wear denim jean pants or denim shirts, but they have a tendency to avoid these denim products due to skin allergies that are caused by a reaction to a chemical dye in the denim fabric.

In the production of the paper yarn, a Hanji paper yarn is produced in almost the same process system as Japanese paper yarn, so the properties of the two paper yarns are quiet similar (Kim et al. 2006; Kim and Park 2008; Itoi 2001; Ishikawa and Shinohara 2001).

In Korea, the Hanji paper yarn is made of Hanji paper sheets, so it has a high bulkiness.

The thickness of paper yarn is greater than that of the same count of cotton yarn. As a result, the Hanji paper yarn is evaluated as a lightweight yarn because Hanji paper yarn’s diameter is larger meaning that the apparent specific gravity is lower (Kim et al. 2007; Park 2012). Therefore, it is possible to produce a lightweight denim fabric that actually feels lighter when worn by using the Hanji paper yarn as the weft. This is because the Hanji paper yarn is a paper yarn and is lightweight by its characteristic of yarn structure and is fast in absorption rate and drying speed rates. Therefore, Hanji denim fabric is a lightweight fabric material with a low specific gravity compared to existing denim fabric resulting in having excellent form stability and comfort.

On the other hand, the core spun yarn used to impart elasticity to fabrics and their usage has recently been increasing. Most significantly, in the production of denim fabrics when the core spun yarn and the paper yarn are used properly as weft, it is found

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Park and Kim Fash Text (2018) 5:26

that the disadvantages of the paper denim fabric’s heaviness, roughness, and wrinkles caused by low stretchability, can be greatly improved.

In general, yarn count of the weft for commonly used cotton denim fabrics in summer and winter are respectively about 15 and 10 Ne. Taking this into consideration when calculating the count of final Hanji combination yarn, a single paper yarn count of the summer and winter usage is appropriate with the count of 30 and 15 Ne respectively based on the core spun yarns 30 Ne. Thus, when weaving with the paper yarn and the core spun yarn in the weaving process, according to the season, it is also advised to select each weft yarn within a similar yarn count range compared to the preferred cotton yarn count.

Therefore, in this study, we aim to manufacture the Hanji denim fabric by using either of these two yarn types for the weft: of the Hanji combination yarn (combined Hanji paper yarn with core spun yarn) or by inserting the Hanji paper yarn and the core spun yarn in a 1:1 ratio. In the warp, we plan to use two kinds of existing yarns dyed with a chemical indigo dyestuff and a natural indigo dyestuff (blue color). After manufacturing Hanji denim fabrics, we plan to test the properties of the developed Hanji denim fabrics and the existing denim fabrics to compare them. This study also plans to suggest commercialization of denim fabric products utilizing the Hanji denim fabrics that have the improved properties such as light fabric weight, stretch, and comfort.

Methods Manufacturing of Hanji paper yarn and combination yarn

The paper yarns used in the weft were made into two types, single yarn and combination yarn. First, in the manufacturing process of a single yarn, a paper sheet was cut to a pre-determined width to make a tape yarn, and after that the single yarn was produced by adding a proper twist to the tape yarn through a twisting machine. In other words, the Hanji paper sheet, with the weight of 13 g/m2, was cut into the tape yarn in the width of 2.75 and 3.75 mm. Then, the Hanji paper yarns, count of 16 and 11 Ne, were produced after twisting 600 and 520 tpm (Z-twist), respectively, using a twisting machine (Murata® 363). The combination yarn was manufactured by combining paper yarn and core spun yarn. In this study, Hanji paper yarn of 16 or 30 Ne was plied in S-twist with the core spun yarn [cotton (sheath)/spandex (core)]. After that, the structures of Hanji combination yarns were stabilized through the steam setting for 14 min at 105 °C. With this process, the count of Hanji combination yarn produced was 10 and 15 Ne, respectively.

Manufacturing of Hanji denim fabrics

Table 1 shows the specifications of Hanji denim fabrics. Denim fabrics were woven in twill (3/1) using an air jet loom (TOYOTA®, JA4SF) and the weft (Hanji paper yarn and combination yarn) inserting speed was approximately 560–570 rpm. The warp was used in two types of cottons: a cotton yarn (8 Ne) dyed with chemical vat dyestuff and a cotton yarn (10 Ne) dyed with natural vat dyestuff (indigo). Four kinds of weft were used so that eight kinds of denim fabrics were produced. For weaving of the denim fabrics, the combination yarns were singly inserted, while the single yarns and core spun yarns were inserted in a 1:1 ratio. Raw materials were produced through the process of singeing,

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Park and Kim Fash Text (2018) 5:26

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Table 1 Specifications of Hanji denim fabrics Yarn specification (abbreviation)

Fabric density (warp × weft per inch)

Warp

Weft

Raw fabric Finished fabric

Rope-dyed cotton yarn (8 Ne; CY8)

Combination yarn (10 Ne; 67 × 52 COY10): [Hanji paper yarn (16 Ne)/core spun yarn (30 Ne)]

73 × 55

DF2 (C8)

Combination yarn (15 Ne; 66 × 55 COY15) [Hanji paper yarn (30 Ne)/core spun yarn (30 Ne)]

75 × 61

DF3 (C8)

Hanji paper yarn (11 Ne; HPY11) + core spun yarn (10 Ne; CSY10)

66 × 46

75 × 52

DF4 (C8)

Hanji paper yarn (16 Ne; HPY16) + core spun yarn (16 Ne; CSY16)

66 × 43

77 × 55

DF1 (C10)

Cheese-dyed cotton yarn Combination yarn (10 Ne; 69 × 53 (10 Ne; CY10) COY10): [Hanji paper yarn (16 Ne)/core spun yarn (30 Ne)]

75 × 56

DF2 (C10)

Combination yarn (15 Ne; 69 × 55 COY15) [Hanji paper yarn (30 Ne)/core spun yarn (30 Ne)]

79 × 60

DF3 (C10)

Hanji paper yarn (11 Ne; HPY11) + core spun yarn (10 Ne; CSY10)

69 × 52

78 × 56

DF4 (C10)

Hanji paper yarn (16 Ne; HPY16) + core spun yarn (16 Ne; CSY16)

70 × 56

83 × 60

Sample code (denim fabric)

DF1 (C8)

S1 (Stretch)

Cotton yarn

Cotton yarn + core spun yarn

–

67 × 50

S2 (Stretch)

Cotton yarn

Core spun yarn

–

82 × 67

desizing, laundry (shrink-proof ), and tenter process. Table 1 shows the material specifications of Hanji denim fabrics and existing denim fabrics (S1, S2) in the market.

Evaluation of properties of Hanji paper yarn and its woven fabric

The tensile properties and yarn count of the Hanji single yarn and combination yarn were measured according to KSK ISO 2062 and KSK ISO 2060 (Skein method) respectively. The colorfastness to washing and the dimensional change in washing and drying of the fabric were measured by KSK ISO 105-C06 (A2S) and KSK ISO 5077, respectively.

The elastic recovery and colorfastness to light were measured by KSK 0352 and KSK ISO 105-B02 (Xenon arc). Drying velocity and absorption velocity were measured by KSK 0815 (6.28.1-A) and KSK 0815 (6.27.1-B), respectively. The surface structures of Hanji paper yarns and combination yarns were observed by scanning electron microscopy (SEM) and those of Hanji denim fabrics were measured by a video microscope system (Sometech Inc.). Fabric specific gravity was determined by mass per unit volume commonly expressed, in grams per cubic centimeter.

Park and Kim Fash Text (2018) 5:26

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2.5

Breaking stress (gf/d)

2.0

1.5

1.0

0.5

0.0 CY8

CY10 HPY11 HPY16 CSY10 CSY16 COY10 COY15 Yarn symbol

Fig. 1 Breaking stress of warp and weft yarn used for Hanji denim fabrics

Results and discussion Physical properties of yarns

Figures 1 and 2 present the tensile properties of the warp and weft yarn used to develop Hanji denim fabrics. The breaking stress of Hanji paper yarn was lower than those of cotton yarn and core spun yarn, but the paper yarn maintained relatively high breaking strain. Since the Hanji combination yarn was obtained by doubling and twisting the structure of Hanji paper yarn and core spun yarn, the weaving ability was made more complimentary by the increased tensile strength of Hanji paper yarn. Empirically, when the paper yarn is used as the weft yarn, it is known that reducing the weft inserting speed slightly prevents yarn breakage since the paper yarn has a lower breaking stress than that of the same count of cotton yarn.

Figure 3 shows the surface structure of the warp and weft yarn used in this study. Two types of warp (cotton yarn) were used, 8 and 10 Ne, respectively. The former was a ropedyed cotton yarn and the latter was a cheese-dyed cotton yarn. In the surface structure of the yarns, the rope-dyed cotton yarn showed a rather bulky structure and the cheesedyed cotton yarn showed a compact structure.

On the other hand, for the denim fabrics, the Hanji paper single yarn, core spun yarn, and Hanji combination yarn were used as the weft. As shown in Fig. 3, the twisted shape of Hanji paper yarn showed a stable structure with little fluff on the surface unlike that of cotton yarn. The core spun yarn had a slightly bulky structure because the cotton yarn enveloped a spandex filament (core yarn). In the existing denim fabrics, the use of core spun yarn as the weft began with the development of skinny denim products in recent

Park and Kim Fash Text (2018) 5:26

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12

10

Breaking strain (%)

8

6

4

2

0 CY8

CY10 HPY11 HPY16 CSY10 CSY16 COY10 COY15 Yarn Symbol

Fig. 2 Breaking strain of warp and weft yarn used for Hanji denim fabrics

years, and core spun yarns were commonly used to improve the surface properties of core yarns and to produce stretch fabrics. Also, the structure of Hanji combination yarns showed that two kinds of yarns, the Hanji single yarn and the core spun yarn, were combined in a stable form.

The study evaluated the optimal weft inserting speed with two cases using Hanji combination yarn alone and Hanji paper yarn and core spun yarn in a 1:1 ratio. As a result, the optimal weft inserting speed (approximately 620 rpm) for the Hanji paper yarn was approximately 90% of the cotton yarn with the same yarn count. This is because we believe the tensile strength of Hanji paper yarn and Hanji combination yarn is lower than that of ordinary cotton yarn.

Figure 4 shows the surface structure of the Hanji denim fabrics. The denim fabrics of DF1 (C10) to DF4 (C10) had some natural vat dyestuff (indigo) come off in the processing and the dyestuff migrated into the weft yarn so that warp and weft yarns were not clearly distinguishable resulting in slightly lowering the colorfastness to washing.

However, in general, the appearance of most of Hanji denim fabrics developed through the study seemed favorable and there was not a significant difference from the existing denim fabrics (S1 and S2) which were commercialized.

Physical properties of Hanji denim fabrics

As shown in Table 1 and Fig. 5, due to the shrinkage in finishing process, the finished fabric density increased significantly compared to the raw fabric. Most of the produced denim fabrics showed less than ± 5% change in the dimensional change in washing and

Park and Kim Fash Text (2018) 5:26

Sample code

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Surface structure

Sample code

CY8

HPY16

CY10

CSY16

HPY11

COY16

Surface structure

Fig. 3 SEM micrographs of the surface structure of warp and weft yarn

drying, which means commercialization of Hanji denim fabrics is possible. Overall, the denim fabric with rope-dyed yarn had a lower dimensional change than the fabric with cheese-dyed yarn, which indicated the rope-dyed yarn denim fabric had better dimensional stability. Therefore, it is suggested that the denim fabrics using cheese-dyed yarn are needed another separate treatment, such as a sanforizing finish to prevent fabric shrinkage. Also, in the same denim fabrics, the Hanji denim that used the Hanji combination yarn as the weft was higher in dimensional change in washing and drying than that of the Hanji denim that used Hanji single yarn and the core spun yarn in a 1:1 ratio.

Table 2 shows the specific gravity, colorfastness, and elastic recovery rate of Hanji denim fabrics. Generally, in fabrics of the same weight, the characteristics of the fabrics where consumers can experience its lighter weight and the light feeling of wearing are very important to the consumers. In the study, the apparent specific gravity of the Hanji denim fabrics (0.471–0.539) produced in this study was lower than that of the existing denim fabrics (0.567–0.577), so the lighter weight can be easily noticed when worn.

This seemed to be due to the large thickness and bulky structure of the Hanji paper yarn compared to the same yarn count of cotton yarn. Importantly, the denim fabric with rope-dyed yarn on the warp showed a lower apparent specific gravity than that of fabric with the cheese-dyed yarn, resulting in a lighter wearing weight. In other words, in the cheese-dyeing process, since winding and unwinding tension from the dyeing bobbin was high, the yarn became less bulky and a smoother structure was obtained.

Park and Kim Fash Text (2018) 5:26

Sample code (Denim fabric)

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Surface structure

Sample code (Denim fabric)

DF1(C8)

DF1(C10)

DF2(C8)

DF2(C10)

DF3(C8)

DF3(C10)

DF4(C8)

DF4(C10)

S1

S2

Surface structure

Fig. 4 Photographs of the surface structure of Hanji denim fabrics (× 40)

The colorfastness to washing (color change and staining) showed a higher chance of commercialization in all manufactured and existing commercial denim fabrics. However, the results of colorfastness to light showed differently; the colorfastness of the denim fabrics that used the chemical dyestuff as the warp yarn was four grades above while that of the denim fabric that used the natural dyestuff was graded as grade 3 or grade 3–4. When compared with the existing denim fabric products (S1, S2), the developed denim fabrics using synthetic dyestuff as the warp yarn seemed to have no problem in merchandising. On the other hand, the colorfastness to light of the indigo natural dyestuff was lower than the chemical dyestuff, which indicated the stability against daylight was slightly lower. However, considering that denim fabric products such as jean pants and jean jackets were recognized as premium denim fabrics in which the indigo

Park and Kim Fash Text (2018) 5:26

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Warp Weft

Demensional change (%)

Denim fabric

Fig. 5 Dimensional change in washing and drying of Hanji denim fabrics

Table 2 Specific gravity, colorfastness, and elastic recovery rate of Hanji denim fabrics Thickness (mm)

Sample code (denim fabric)

Weight (g/ m 2)

DF1 (C8)

375

0.74

DF2 (C8)

349

0.69

DF3 (C8)

385

DF4 (C8)

Specific gravity

Colorfastness to washing (grade)

Colorfastness to light (grade)

Elastic recovery rate (%)

Color change

Staining

Warp Weft

0.507

4–5

4–5

Above 4

54

77

0.506

4–5

4–5

Above 4

56

75

0.76

0.507

4–5

4–5

Above 4

52

78

367

0.78

0.471

4–5

4–5

Above 4

69

75

DF1 (C10)

361

0.67

0.539

4–5

4–5

3–4

38

41

DF2 (C10)

320

0.63

0.508

4–5

4–5

3–4

44

56

DF3 (C10)

358

0.68

0.526

4–5

4–5

3–4

52

71

DF4 (C10)

361

0.68

0.531

4–5

4–5

3

54

70

S1

380

0.67

0.567

4–5

4

Above 4

50

70

S2

352

0.61

0.577

4–5

4–5

Above 4

67

79

dyes gradually disappear in the course of repeated washing and dehydration, we believe that the denim fabric using the natural dyestuff as the warp is able to commercialize sufficiently.

For the elastic recovery rate of Hanji denim fabrics developed in the study, we compared the result with that of existing stretch denim fabrics (S1, S2). Basically, the standard denim fabrics are made of unbleached cotton yarn, so there is no elasticity and many wrinkles. Recently, denim fabrics have been given elasticity according to consumers’ needs. The existing denim fabrics, which were compared with the Hanji denim fabric

Park and Kim Fash Text (2018) 5:26

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$EVRUSWLRQ 9HORFLW\ PP PLQ :DUS $EVRUSWLRQ 9HORFLW\ PP PLQ :HIW

8GNQEKV[

Denim fabric

Fig. 6 Drying velocity and absorption velocity of Hanji denim fabrics

produced in this study, were denim fabrics with medium stretch (S1) and high stretch (S2). The approximate structure of the existing denim fabrics (S1, S2), using the analysis of fabric structure, showed cotton yarns (navy color) and stretch yarns used as warp and weft, respectively. Most Hanji denim fabrics produced, except for the DF1 (C10) and the DF2 (C10), showed a higher elastic recovery rate than that of existing medium stretch denim fabric (S1). The high recovery rate trend resulted mainly in the denim fabrics using the rope-dyed yarn.

Figure 6 shows the drying velocity and absorption velocity of Hanji denim fabrics. The drying velocity of Hanji denim fabrics increased as the fabric’s weight increased. This resulted because as the weight increases, the hydrophilic fiber of the fabric absorbs a large amount of moisture, leading to a longer drying time. Also, the existing denim fabrics showed a similar tendency, and compared with Hanji yarn denim fabrics, the drying speed of the existing denim fabrics was almost the same (or slightly faster). On the other hand, the absorption velocity of Hanji denim fabrics showed significant differences. The Hanji denim fabric dried much faster than those of existing denim fabrics. This tendency is due to the high absorbency of Hanji yarn compared to cotton yarn. Especially, the tendency with Hanji yarn and core yarn with a 1:1 ratio showed a higher absorption velocity than that of the cotton yarn. Overall, the Hanji denim fabrics showed a higher absorption velocity than those of the existing denim fabrics (S1, S2). In addition, there was no significant difference in the drying velocity between the Hanji denim fabric and the existing denim fabrics even though the Hanji denim fabrics absorb more moisture compared to the existing denim fabrics.

Park and Kim Fash Text (2018) 5:26

Fig. 7 Denim wear products using manufactured Hanji denim fabrics

Therefore, it was considered that Hanji denim fabrics are suitable for summer use product development considering that general Hanji fabrics have pleasant cooling characteristics in addition to the excellent absorption velocity and drying velocity. This is because the Hanji yarn developed and used in this study is a paper yarn composed of mulberry and manila hemp fiber. The characteristics of fiber and structure of this paper yarn give its cooling characteristics to Hanji denim fabrics. Figure 7 shows design applications in jean pants, shirts, and dresses that were manufactured using the Hanji paper denim fabric developed in this study. It showed no difference compared to the existing denim fabric (cotton fabric) in the process of fabric cutting, sewing, and its wearability.

Conclusions With the popular use of denim fabric and of the advantages of paper yarns, we aimed to develop the Hanji denim fabric with Hanji combination yarn or with the Hanji paper yarn and core spun yarn in a 1:1 ratio as the weft. As the warp yarn, chemical vat and natural dyestuffs were used. We tested the properties of the developed Hanji paper yarns, combination yarns, and Hanji denim fabrics. The summary and conclusions are as follows.

With regard to the physical properties of yarns, the breaking stress of Hanji paper yarn was lower than those of the cotton yarn and the core spun yarn, but the paper yarn maintained a relatively high breaking strain. The Hanji combination yarn has been improved the weaving ability by complementing the tensile strength of Hanji paper yarn.

In the surface structure of the yarn, the rope-dyed cotton yarn showed a rather bulky structure while the cheese-dyed cotton yarn showed a compact structure. The structure of Hanji combination yarns showed that the Hanji single yarn and core spun yarn were tightly combined resulting in a stable form. The optimal weft inserting speed for the Hanji paper yarn was approximately 90% of the cotton yarn with the same yarn count.

Also, the appearance of most Hanji denim fabrics produced showed no significant difference from the existing stretchable denim fabrics indicating commercialization of Hanji denim fabrics as highly possible.

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Park and Kim Fash Text (2018) 5:26

With regard to the physical properties of developed denim fabrics, the apparent specific gravity of the Hanji denim fabrics produced was lower than that of the existing denim fabrics, so garments when worn could feel light. The dimensional change in washing and drying: the rope-dyed yarn denim fabrics showed better dimensional stability than the fabrics with cheese-dyed yarns. The colorfastness to washing showed a higher chance of commercialization in all manufactured and existing commercial denim fabrics. The colorfastness to light, the developed denim fabrics using synthetic dyestuff as the warp yarn seemed to have no problem in merchandising while the stability against daylight of natural dyestuff was slightly lower. The elongation recovery rate of Hanji denim fabrics showed that most developed Hanji denim fabrics had a similar elongation recovery rate to the existing denim fabrics that had medium stretchability (S1). The drying velocity of Hanji denim fabrics showed a tendency to increase with increasing fabric weight while the absorption velocity of Hanji denim fabrics showed significant differences: Hanji denim fabric was much faster to dry than those of existing denim fabrics.

Through the study, we found that the developed Hanji denim fabrics had several advantages compare to the existing denim fabrics. It has a low apparent specific gravity due to it being a paper yarn while it has a dimensional stability. Further, there is a higher chance of commercialization in colorfastness to washing with a medium stretchability.

Lastly, a drying velocity is a similar to existing denim fabrics while an absorption velocity is fast in comparison to that of existing denim fabrics.

Therefore, the study suggests that the Hanji denim fabric is a good fabric for summer product development usage such as jean pants, jean skirts, and jean shirts since it generally has many pleasant cooling characteristics in addition to the excellent absorption velocity with a lower fabric weight for comfortable wearing. Through this study, we hope that the Hanji denim fabrics contribute to meet consumers’ needs who have concerns in healthcare issues and in environmental issues. This new fabric creates a new interest on the market development making it a high value-added business.

Authors’ contributions Both TYP and MOK carried out the literature review and the research frame work. TYP conducted experiments and drafted the manuscript. MOK developed denim design experiments and result analysis. Both authors read and approved the final manuscript.

Author details 1 Howon University, Gunsan, South Korea. 2 University of Cincinnati, Cincinnati, USA. Competing interests The authors declare that they have no competing interests.

Ethics approval and consent to participate Not applicable.

Publisher’s Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Received: 22 December 2017 Accepted: 4 April 2018

References Ishikawa, J., & Shinohara, H. (2001). Paper yarn, wrinkle crush-processed paper and knitted and woven fabric. Japan Patent No. 200441.

Itoi, T. (2001). Method and apparatus for producing paper yarn. JP Patent 295146.

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Park and Kim Fash Text (2018) 5:26

Juciene, M., Dobilaite, V., & Kazlauskaite, G. (2006). Influence of industrial washing on denim properties. Materials Science, 12(4), 355–359.

Kan, C., & Wong, W. (2011). Color properties of cellulose-treated cotton denim fabric manufactured by torque-free ring spun yarn. Textile Research Journal, 81(9), 875–882.

Khedher, F., Dhouib, S., Msahli, S., & Sakli, F. (2011). Study of the influence of matter and finishing treatments on the denim garment shade. International Journal of Clothing Science and Technology, 23(2/3), 107–118.

Kim, H. C., Kim, W. Y., Kim, S. B., Choi, C. Y., & Kim, K. H. (2006). Method for manufacturing of paper yarn. Korea Patent No. 10-0654155.

Kim, H. C., Kim, W. Y., Kim, S. B., Choi, C. Y., & Oh, Y. S. (2007). Composite yarn having high elongation and manufacturing method thereof. Korea Patent No. 10-0689604.

Kim, K. H., & Park, T. Y. (2008). Method for manufacturing covering yarn using Korean paper. Korea Patent No. 10-0820870.

Kim, M. O., Uh, M. K., & Park, M. J. (2009). Changes in mechanical properties and fabric hand of the washing-finished denims. Journal of the Korean Society of Living Environmental System, 16(2), 162–171.

Ozdil, N. (2008). Stretch and bagging properties of denim fabrics containing different rates of elastane. Fibers and Textiles in Easter Europe, 16(1), 63–67.

Park, T. Y. (2012). Properties of plied yarn and Hanji tape yarn/filament yarn based on various twist numbers and characteristics of the knitted fabric. Journal of the Korean Society of Knit Design, 10(1), 64–72.

Park, T. Y., & Lee, C. G. (2016). Weft yarns of denim fabric having improved elasticity and tactility. Korea Patent No. 10-2016-0078236.

Page 13 of 13

PAPERmaking!

O THE PUBLISHERS U S S OF O PAPER TECHNOLOGY INTERNATIONAL FROM

Volume 6, Number 1, 2020

Enhanced strength, stiffness and elongation potential of paper by spray addition of polysaccharides Anders Strand, Jarmo Kouko, Antti Oksanen, Kristian Salminen, Annika Ketola, Elias Retulainen, Anna Sundberg.

The effects of spray additions of alginate, cationic guar gum, or chitosan on paper properties were determined. The aim of this study was to enhance the mechanical properties of papers after unrestrained drying, while maintaining or increasing the extraordinarily high elongation potential of these papers. The mechanical characteristics of the different polysaccharides were determined by tensile test of model films.

Alginate resulted in very strong and stiff films with low strain at break values, while cationic guar gum and chitosan resulted in significantly weaker and softer films with high strain at break. The polysaccharide solutions were sprayed onto wet handsheets, and the paper properties were measured after restrained and unrestrained drying. The spray additions increased the tensile index, density, and tensile stiffness of the handsheets. Spray addition of alginate resulted in stiffer and stronger paper than the other tested polysaccharides. Alginate was able to increase the tensile index of the paper by 54% and the tensile stiffness by 32% after restrained drying. All strain at break values in this study correlated linearly with paper shrinkage during drying. Alginate, which gave extremely strong and stiff model films, enhanced paper shrinkage, effectively lowered the air permeability of the paper, and formed a polysaccharide film on top of the paper, was found to be the most promising candidate for future packaging applications.

Contact information: A. Strand & A. Sundberg, The Laboratory of Wood and Paper Chemistry, Åbo Akademi University, Porthaninkatu 3, FI-20500 Turku, Finland J. Kouko, A. Oksanen, K. Salminen, A. Ketola & E. Retulainen, VTT, Koivurannantie 1, FI-40400 Jyväskylä, Finland Cellulose (2019) 26:3473–3487 https://doi.org/10.1007/s10570-019-02308-0 This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creat iveco mmons .org/licen ses/by/4.0/).

The Paper Industry Technical Association (PITA) is an independent organisation which operates for the general benefit of its members – both individual and corporate – dedicated to promoting and improving the technical and scientific knowledge of those working in the UK pulp and paper industry. Formed in 1960, it serves the Industry, both manufacturers and suppliers, by providing a forum for members to meet and network; it organises visits, conferences and training seminars that cover all aspects of papermaking science. It also publishes the prestigious journal Paper Technology International and the PITA Annual Review, both sent free to members, and a range of other technical publications which include conference proceedings and the acclaimed Essential Guide to Aqueous Coating.

Page 1 of 16

Article 3 – Polysaccharides as Strength Enhancers

Cellulose (2019) 26:3473–3487 https://doi.org/10.1007/s10570-019-02308-0

(0123456789().,-volV) ( 01234567 89().,-volV)

ORIGINAL RESEARCH

Enhanced strength, stiffness and elongation potential of paper by spray addition of polysaccharides Anders Strand . Jarmo Kouko . Antti Oksanen . Kristian Salminen .

Annika Ketola . Elias Retulainen . Anna Sundberg

Received: 5 July 2018 / Accepted: 1 February 2019 / Published online: 8 February 2019 Ó The Author(s) 2019

Abstract The effects of spray additions of alginate, cationic guar gum, or chitosan on paper properties were determined. The aim of this study was to enhance the mechanical properties of papers after unrestrained drying, while maintaining or increasing the extraordinarily high elongation potential of these papers. The mechanical characteristics of the different polysaccharides were determined by tensile test of model films. Alginate resulted in very strong and stiff films with low strain at break values, while cationic guar gum and chitosan resulted in significantly weaker and

A. Strand (&) A. Sundberg The Laboratory of Wood and Paper Chemistry, Åbo Akademi University, Porthaninkatu 3, FI-20500 Turku, Finland e-mail: anders.strand@abo.fi A. Sundberg e-mail: anna.sundberg@abo.fi

softer films with high strain at break. The polysaccharide solutions were sprayed onto wet handsheets, and the paper properties were measured after restrained and unrestrained drying. The spray additions increased the tensile index, density, and tensile stiffness of the handsheets. Spray addition of alginate resulted in stiffer and stronger paper than the other tested polysaccharides. Alginate was able to increase the tensile index of the paper by 54% and the tensile stiffness by 32% after restrained drying. All strain at break values in this study correlated linearly with paper shrinkage during drying. Alginate, which gave extremely strong and stiff model films, enhanced paper shrinkage, effectively lowered the air permeability of the paper, and formed a polysaccharide film on top of the paper, was found to be the most promising candidate for future packaging applications.

J. Kouko A. Oksanen K. Salminen A. Ketola E. Retulainen VTT, Koivurannantie 1, FI-40400 Jyväskylä, Finland e-mail: jarmo.kouko@vtt.fi A. Oksanen e-mail: antti.oksanen@vtt.fi K. Salminen e-mail: kristian.salminen@vtt.fi A. Ketola e-mail: annika.ketola@vtt.fi E. Retulainen e-mail: elias.retulainen@vtt.fi

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Graphical abstract

Keywords Paper properties Alginate Guar gum Chitosan Spraying Extendable fiber network Unrestrained drying Paper shrinkage

Introduction Novel bio-based alternatives to fossil-based plastics are needed for future packaging applications. So far, the bio-based alternatives have been limited by their brittleness, low thermal stability, medium gas barrier properties, and low solvent resistance (e.g. against water) (Yu et al. 2006; Rhim 2012). Cellulose is an optimal choice of raw material for such applications, since it is biodegradable, renewable, recyclable, and currently available in large quantities. It has been reported that highly extensible cellulose-based fiber networks can be created, and can be molded into 3D shapes using available forming techniques (Svensson et al. 2013; Vishtal et al. 2014; Vishtal and Retulainen 2014b). Mechanical treatments of fibers and additions of various additives have been used in combination with unrestrained drying to improve the extensibility of fiber networks (Seth 2005; Zeng et al. 2013; Khakalo et al. 2014, 2017a; Vishtal et al. 2015; Strand et al. 2017). Paper shrinkage during unrestrained drying has been shown to cause micro-compressions in the longitudinal direction of the fibers (Page and Tydeman 1962). It is known that unrestrained drying affects the mechanical properties of paper quite severely. Unrestrained drying of paper increases its

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strain at break significantly at the cost of tensile index and tensile stiffness (see e.g. Zeng et al. 2013; Strand et al. 2017). Stretching a shrunken fiber network is to a certain extent a reversal of shrinkage, as the applied forces tend to pull out the kinks and micro-compressions, both between and within the bonds. As intrafiber hydrogen bonds gradually break, the micro-compressions are released, allowing for a greater extension of the fiber network before it breaks due to actual failure of fiber–fiber bonds and resulting localization of stresses. For a pulp with constant refining level, a linear correlation between strain at break and negative strain, i.e. shrinkage, has previously been reported for paper, both in machine direction and cross direction (Wahlström 1999). However, recent results indicate that the relationship between shrinkage and elongation is non-linear in large scale and that the same dimensional contraction brought about by shrinkage can be strained out in tensile testing (Kouko and Retulainen 2018). It was shown that the strain at break of paper after unrestrained drying increases linearly with increasing refining energy and that it influences most mechanical properties of the paper considerably (Strand et al. 2018).

Addition of hydrophilic polysaccharides or polyelectrolytes is known to enhance the bonding between fibers and is the most common strategy to increase paper strength (Hubbe 2006; Hubbe et al. 2009; Fornue et al. 2011). For successful wet-end additions, the additives need to be retained to the fibers and have sufficiently high molar mass to avoid migration into the fiber pores (Pelton 2004; Hubbe 2006; Fornue et al.

Cellulose (2019) 26:3473–3487

2011). It is also beneficial if the additives are hydrophilic and able to form hydrogen bonds. Dry strength agents are generally water-soluble polymers, meaning that the effectiveness of the additives is largely governed by the retention of the additive to the fiber network. Recent studies have been able to circumvent the reliance on retention to some extent by performing spray additions of various additives onto already formed, wet paper sheets (Lindqvist et al.

2014; Khakalo et al. 2014; Vishtal and Retulainen 2014a; Vishtal et al. 2015). This methodology has previously been used with agar, gelatin, and combinations of gelatin and agar to enhance paper properties. Spray additions of agar and gelatin in combination with unrestrained drying have been shown to result in high strain at break of paper. In the current study, some additional polysaccharides were selected for spray addition.

Alginates are anionic unbranched block co-polymers of b-D-mannosyluronic acids and a-L-gulosyluronic acids linked 1–4. The blocks can be either homopolymers of either mannosyluronic or gulosyluronic units or a heteropolymer of both units (Fig. 1; Gacesa 1988; BeMiller and Whistler 1996). The conformation of these units are different; blocks of mannosyluronic acids will therefore form a ribbonlike structure while blocks of gulosyluronic units will form a buckled chain. Alginate readily forms hydrogels and are used as stabilizers, gelling agents, thickening agents or as films or fibers.

Guar gum is extracted from the pods of the guar plant (Cyamopsis tetragonoloba) (Chudzikowski 1971; BeMiller and Whistler 1996; Mudgil et al.

2014). This polysaccharide have a linear backbone of 1–4-linked b-D-mannosyranose units with 1–6-linked a-D-galactopyranos as side groups. The ratio of mannose to galactose is about 1.6–1.8:1 (Fig. 1; BeMiller and Whistler 1996; Mudgil et al. 2014).

Guar gum is water soluble and has a very high molar mass. Guar gum is used as additives in e.g. food, pharmaceuticals, paper, textile, explosives, oil well drilling and cosmetics industry (Mudgil et al. 2014).

Guar gums can easily be modified and cationic guar gum (guar hydroxypropyltrimonium chloride) is used in e.g. cosmetics as an emulsifier.

Chitin is, after cellulose, the second most produced polysaccharide annually in the world. Chitin is found in the support material of crustaceans, as shrimp and crabs, and insects. It is a polysaccharide that is

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composed of 1–4-linked b-N-acetyl-D-glucosamine (Fig. 1; Rinaudo 2006). Chitin is not water soluble but its N-deacetylated derivate, chitosan, is soluble in water at slight acidic conditions. Chitosan is the only pseudonatural cationic polysaccharide, with a pKa of about 6.3–6.7, and it also contains a high percentage of nitrogen (Ravi Kumar 2000; Rinaudo 2006). Chitosan is biocompatible, biodegradable and non-toxic and it is used in many application such as food, cosmetics, textiles, pharmaceuticals and nanomaterial (Ravi Kumar 2000; Rinaudo 2006; Shukla et al. 2013).

The aim of this study was to enhance the tensile strength, tensile stiffness and strain at break of handsheets after restrained and unrestrained drying by spray application of different available polysaccharides onto wet handsheets. Model films from the polysaccharides were also prepared and tested in order to gain information about their mechanical properties.

Materials and methods Materials ECF-bleached, once-dried softwood kraft pulp was obtained from a Finnish pulp mill. Alginic acid sodium salt from brown algae (alginate) was obtained from Sigma–Aldrich. According to the supplier, the alginate consisted of approximately 61% mannosyluronic units, and 39% gulosyluronic units, with 19–25% carboxyl groups, and an approximate Mw of 240 kDa. The alginate powder was directly dissolved in distilled water to a concentration of 1 wt% with the aid of boiling and agitation. Chitosan (medium molecular weight) was obtained from Sigma–Aldrich.

According to the supplier, the Mw of the chitosan was 190–310 kDa, and the degree of deacetylation was 75–85%. The cationic charge density of the chitosan was 4.7 meq/g, determined by polyelectrolyte titration using a particle charge analyzer (Mütek PCD 03, Mütek Analytic GmbH, Germany; BTG, Switzerland).

The chitosan powder was dissolved in 1–1.5% acetic acid to a concentration of 1 wt% with the aid of boiling and agitation. Cationic guar gum (guar hydroxypropyltrimonium chloride) was obtained from Making Cosmetics, USA. The reported viscosity of a 1% solution (20 rpm, 20 °C) was 3000–4000 cP, according to the supplier. The charge density of the cationic guar gum was 0.8 meq/g, determined by

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Cellulose (2019) 26:3473–3487

Fig. 1 The chemical structures of alginate, cationic guar gum, and chitosan. G gulosyluronic units, M mannosyluronic units

polyelectrolyte titration using a particle charge analyzer. The cationic guar gum powder was dissolved in distilled water to a concentration of 0.5 wt% with the aid of boiling and agitation. Sorbitol was obtained from Sigma–Aldrich and directly dissolved in distilled water to a concentration of 20 wt%. Sorbitol was required as a softener during film casting.

85 mm). The water evaporated from the molds at room temperature during the course of a few days, resulting in model films of the different polysaccharides. The films were then carefully removed from the petri dishes.

Methods

The thickness of the model films were measured using a Lorentzen & Wettre thickness tester with an accuracy of 0.1 lm. Small ‘‘dog bone’’ shaped test pieces were cut from the polysaccharide model films.

The linear area of the test piece was 4 mm in width and 30 mm in length. The tensile tests were performed with an Instron 8872 apparatus, controlled by Bluehill3 software. The chosen straining speed was 2 mm/ min. The tensile tests were performed at least three

Preparation of model films from polysaccharides The solvent casting of the polysaccharide model films were performed similarly to a previously reported method (Rhim 2012). The polysaccharide solution was mixed with sorbitol solution and the mixture was then poured into Teflon-coated petri dishes (diameter

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Testing of model polysaccharide films

Cellulose (2019) 26:3473–3487

times. The obtained raw data was recalculated from load (N) into stress (MPa) and from extension (mm) into strain (dimensionless), in order to determine the elastic modulus of the tested samples.

Polysaccharide viscosity measurements Solutions of the different polysaccharides were prepared with their previously described solvents; 1 wt% of alginate and chitosan, and 0.5% of cationic guar gum. The viscosities of the polysaccharide solutions were determined using a Paar Physica MCR (modular compact reometer) apparatus (rod: CC27, cup: TEZ 150P). The shear rate gradually increased from 0.01 to 1000 s-1 (Fig. 2). The measured viscosity at a shear rate of 1.1 s-1 was 259 mPas for the 1% alginate solution, 251 mPas for the 1% chitosan solution, and 668 mPas for the 0.5% cationic guar gum solution.

Refining of pulp The low-consistency refining of the kraft pulp was performed with a ProLabTM refining station (Valmet, Finland) at Åbo Akademi University (Turku, Finland) according to a previously described procedure (Strand et al. 2017). The Schopper–Riegler (°SR) values of the refined pulp was measured according to ISO 5267-1, and parallel samples of the refined pulp was characterized using a Kajaani Fiberlab optical fiber analyzer (Metso Automation, Finland) (Table 1). The pulp was refined to 135 kWh/t, which corresponded to °SR 25.

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Papermaking procedure Handsheets were formed on a 125 mesh wire in a 165 mm 9 165 mm laboratory sheet former. The handsheets were prepared without recirculation of white water. The aimed grammage of all of the handsheets was 100 g/m2. The handsheets were couched from the wire by pressing, and stored wet (solids content 26–28%) between wet blotter papers in sealed plastic bags at 5 °C until further use.

The polysaccharide solutions were sprayed onto the top side of the wet sheets using a commercial, highvolume, low-pressure (HVLP) gravity feed air spray gun. The top side of the wet sheets were sprayed with polysaccharide amounts corresponding to of 2 and 4% o.d. polysaccharides based on dry paper weight. A wet sheet was placed on a rigid plastic plate on top of a gravimetric scale. The targeted amount of solution was adjusted by controlling the wet weight of the sheet after spraying. Reference sheets were sprayed with an equivalent amount of cold tap water. The sprayed samples were placed on a vacuum box covered with a fabric wire; a vacuum level of approximately 5–10 kPa was applied beneath the sprayed sheet.

The aim of the vacuum treatment was to remove excess water from the sheets and aid the penetration of the polysaccharides into the wet fiber network. Ten handsheets were sprayed for each trial point; five sheets were subjected to restrained drying, and five sheets were subjected to unrestrained drying.

Restrained drying: the sheets treated with polysaccharide solutions were dried on a plate with a blotter, strapped into a drying frame. Unrestrained drying: the treated handsheets were dried in specially built drying frames, between two polymer forming wires with a gap of approximately 3 mm to allow for paper shrinkage during drying, while simultaneously preventing severe cockling and curling of the sheets.

Both, restrained and unrestrained drying methods were performed under standard testing conditions (EN ISO 5269-1:2005E). None of the sheets were wetpressed prior to drying.

Paper testing

Fig. 2 The measured viscosity curves of the polysaccharides in solution

The basis weight of the paper samples was determined according to ISO 536:1995. The thickness was determined according to ISO 534:1998, and the density was determined based on the measured values of the basis

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3478 Table 1 The measured fiber properties of unrefined and low-consistency refined softwood kraft pulp

Cellulose (2019) 26:3473–3487

Unrefined (°SR 12) Fiber length (l) (mm)

1.83

Fines (l) (%)

2.45

Fiber width (lm) Cell wall thickness (lm) (l) Length-averaged values

Curl (%)

weight and thickness. The air permeability of the papers was determined with a Lorentzen & Wettre, L&W Air permeance tester according to ISO 5636-3.

The mechanical properties (i.e. tensile index, stretch, work, and tensile stiffness) of the paper sheets were determined with a Lloyd tensile tester (AMETEK, USA), in accordance with ISO 5270:1998. The straining speed was 100 mm/min in the tensile measurements. Paper samples were conditioned and all testing of the samples took place at a temperature of 23 °C and at 50% relative humidity (EN ISO 5269-3).

Eight parallel measurements were performed. The paper shrinkage during restrained and unrestrained drying was measured and calculated according to the procedure described by Vishtal and Retulainen (2014a). Shrinkages of restrained and unrestrained dried sheets were measured by applying marker holes with known separations in the wet sheets as described

by Khakalo et al. (2017b).

2D formability tests The formability strain and force of the paper samples were measured using a 2D-formability tester at VTT. A detailed description of the measurement procedure and set-up is available in literature (Vishtal and Retulainen 2014a). In this study, the velocity of the forming press was 10 mm/s and the width of the paper sample was 20 mm. The paper samples were set in the tester so that the sprayed surface was not in contact with the heated press. The 2D formability tests were repeated seven times for each trial point.

ProLab refined (°SR 25) 1.83 2.90

28.5

29.7

6.2

7.6

15.3

14.5

Results and discussions Mechanical testing of model films from the polysaccharides Model films were prepared from the different polysaccharides with added sorbitol as softener (50%).

Addition of sorbitol was required in order to successfully prepare polysaccharide films, since these type of films otherwise become too brittle to handle, and crack during drying. It has previously been reported that addition of 50% glycerol as plasticizer was needed when model films were prepared from agar and jcarrageenan in order to avoid brittleness of the films (Rhim 2012). It has also been reported that the tensile strength and Young’s modulus of oat spelt arabinoxylan films was slightly higher with sorbitol than with glycerol at high dosages (Mikkonen et al. 2009).

Therefore, sorbitol was the softener of choice in the current experimental series.

The model films from the different polysaccharides were subjected to mechanical testing. It was immediately evident that the different polysaccharides gave films with very different characteristics (Fig. 3).

Alginate gave the strongest model films, with a

Scanning electron microscopy Scanning electron microscopy (SEM) was performed using a JEOL JSM-IT100 instrument. Images were produced in low-vacuum mode (40 Pa) using backscattered electrons. The accelerating voltage was 10 kV.

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Fig. 3 Examples of the stress–strain curves of polysaccharide model films. To all of the displayed examples, 50% sorbitol had been added as softener

Cellulose (2019) 26:3473–3487

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strength value of 63 MPa (Table 2). The elastic modulus of the alginate film was also quite high, with a value of 2 GPa. However, the strain at break of the alginate film was only 7%. Other studies have reported that the tensile strength of films made from sodium alginate ? 40% glycerol was 12 MPa, their elastic modulus roughly 170 MPa, and their strain at break just below 30% (Yoo and Krochta 2011). It is known that there are quite large variations between available alginate sources and/or qualities; there are variations in the ratio between mannosyluronic and gulosyluronic units, as well as the length of each block depending on source (Lee and Mooney 2012). These model films from alginate had quite extraordinarily high strength and stiffness values.

Chitosan gave significantly weaker model films than alginate, and the elastic modulus was also much lower (Table 2). However, the strain at break of the chitosan films was 55%. Additionally, the stress–strain curves of the chitosan films revealed a distinctive initial stiffness of the films prior to the plastic region of the curves (Fig. 3). The chitosan films could be strained almost seven times further than the corresponding alginate films. Cationic guar gum gave even weaker model films with extremely low elastic modulus (Table 2). The strain at break of films from cationic guar gum was quite high, much like with chitosan. The cationic guar gum films lacked the initial stiffness of chitosan.

These results indicated that there is an inverse relationship between tensile strength and strain at break; stronger polysaccharide films tend to have lower strain at break values. It is known that the mechanical properties of model films from polysaccharides are heavily influenced by the properties of the compounds and their packing possibilities, as well as the amount and type of plasticizer (Arvanitoyannis and Biliaderis 1999; Mikkonen et al. 2009; Yoo and Krochta 2011). After these initial results, the main

focus of the main study was to determine whether or not the characteristic tensile properties of the different polysaccharides were transferable to a fiber network.

The applications were performed as spray additions of the polysaccharides in solution onto pre-formed, wet handsheets.

Spray addition of polysaccharides onto wet handsheets Wet handsheets were sprayed with the different polysaccharide solutions to dosage levels of 2 or 4 wt%. The polysaccharides were alginate, chitosan and cationic guar gum. Sorbitol, 20 and 30% calculated on polysaccharide dry weight, was added to the solutions before spraying as softener.

The tensile index of the handsheets after restrained drying were plotted as a function of their density (Fig. 4). The tensile index of the sprayed reference sheet was 57.2 Nm/g. All of the polysaccharides increased the tensile index and density of the sheets after restrained drying (Table 3). Cationic guar gum increased the tensile index by 7.2–11.0 Nm/g, while chitosan resulted in increases of 5.7–19.1 Nm/g.

Alginate resulted in larger increases in tensile index, between 17.5 and 30.9 Nm/g, reaching a maximum value of 88.1 Nm/g with 2% ? 30% sorbitol. The overall increases in tensile index after restrained drying followed a similar pattern as the results from the tensile tests of the polysaccharide model films; alginate formed the strongest films, while films from chitosan and cationic guar gum were significantly weaker. In previous studies, spray addition of 4% gelatin ? cross-linker or spray addition of 4% gelatin, 4% agar ? cross-linker was required in order to surpass 80 Nm/g after restrained drying (Vishtal et al. 2015).

The tensile index of the handsheets after unrestrained drying were plotted as a function of their

Table 2 The determined values of tensile strength, elastic modulus, and strain at break of model films from the polysaccharides Polysaccharide film

Tensile strength (MPa)

E-modulus (MPa)

Strain at break (%)

Alginate ? 50% sorbitol

63

2045

7

Chitosan ? 50% sorbitol

25

203

55

Cationic guar gum ? 50% sorbitol

18

67

47

50% sorbitol was added as softener

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Fig. 4 Tensile index (Nm/ g) versus density (kg/m3) of handsheets sprayed with the different polysaccharide solutions. The paper properties were measured after restrained (R) and unrestrained (UR) drying.

Ref reference samples. The average values with their standard deviations are shown

Table 3 The mechanical properties of handsheets after restrained drying Restrained drying

Density kg/m3

Tensile index Nm/g

Tensile stiffness s

kNm/g

s

Strain at break

1D shrinkage

Air permeability

%

%

mL/min

s

s

Reference

394.5

58.8

2.3

4.2

0.8

6.7

0.6

nd

2868

367

Reference-sprayed

406.4

57.2

3.1

4.4

0.2

5.8

0.6

1.0

4020

380

2% Alginate (? 20% sorbitol)

493.1

74.7

3.1

5.1

0.2

5.2

0.3

0.7

503

28

2% Alginate (? 30% sorbitol)

507.0

88.1

5.2

5.8

0.1

5.4

0.5

0.2

413

50

4% Alginate (? 20% sorbitol)

495.3

84.0

3.8

5.6

0.2

5.3

0.4

0.1

276

58

4% Alginate (? 30% sorbitol)

484.6

81.4

6.8

5.5

0.2

5.0

0.7

0.2

382

53

2% Cationic guar gum (? 20% sorbitol)

441.5

66.4

3.2

4.3

0.4

6.0

0.5

1.2

2148

229

2% Cationic guar gum (? 30% sorbitol)

430.3

64.4

4.1

4.2

0.1

6.1

0.4

1.8

2366

347

4% Cationic guar gum (? 20% sorbitol)

448.0

68.2

3.9

5.2

0.1

4.9

0.4

1.1

2135

321

4% Cationic guar gum (? 30% sorbitol)

461.5

65.6

2.3

4.3

0.3

6.0

0.3

1.1

1805

193

2% Chitosan (? 20% sorbitol) 2% Chitosan (? 30% sorbitol)

445.3 429.6

76.3 62.9

2.6 1.2

4.3 3.8

0.2 0.3

6.6 6.1

0.4 0.5

nd 1.3

2808 2660

283 230

4% Chitosan (? 20% sorbitol)

457.0

66.0

3.8

4.9

0.1

4.7

0.3

nd

3180

169

4% Chitosan (? 30% sorbitol)

440.3

71.9

4.2

4.8

0.1

5.0

0.4

05

3212

314

The average values, as well as their standard deviations (s) are reported. The additions were calculated as wt% of o.d. pulp

density (Fig. 4). The density of the handsheets was signiďŹ cantly lower due to the considerable paper shrinkage during the drying process. It is known that unrestrained drying alters the mechanical properties of paper quite signiďŹ cantly (see e.g. Strand et al. 2017).

When comparing the untreated reference sheets with reference sheets sprayed with tap water, it was seen that the spraying procedure alone lowered the density of the handsheets (Fig. 4). All of the polysaccharide

123

additions increased the tensile index of the sheets after unrestrained drying. Alginate resulted in the largest increases in tensile index also in this case, but the differences to cationic guar gum and chitosan were quite small. It was previously reported that spray addition of 2 or 4% agar was only able to increase the tensile index of paper by approximately 3 Nm/g after wet-pressing, unless a cross-linker was added (Vishtal and Retulainen 2014a). Additions of 4% agar ?

Cellulose (2019) 26:3473–3487

cross-linker gave similar tensile index values as addition of 2% alginate. Similarly, it has been reported that spray addition of 4% gelatin increased the tensile index of paper from 59.3 to 70.3 Nm/g after wetpressing and unrestrained drying, i.e. by 11 Nm/g (Khakalo et al. 2014). The tensile index could, once again, be increased further by addition of glutaraldehyde as a cross-linker. As a comparison, addition of 2% alginate in the current study increased the tensile index of the papers by 18.9 Nm/g without wetpressing, which is quite substantial. The addition of 2% alginate resulted in a similar tensile index values as sequential addition of 4% gelatin and 4% agar after unrestrained drying (Vishtal et al. 2015).

Plotting the tensile index versus density of papers after restrained and unrestrained drying revealed an almost linear dependency (Fig. 4). It is known that the relative bonded area is heavily linked to paper density, and that there is a strong relationship between relative bonded area and tensile strength (Page 1969). A linear dependency have been shown to exist between the relative bonded area and sheet density using bleached softwood kraft pulps of different mixtures of springwood and summerwood fibers (Retulainen and Ebeling 1993). A linear dependency has also been shown between the determined BET-area of papers and their tensile index; the tensile index increased as the amount of unbound areas in the papers decreased (Lindström et al. 2016). Even for the current results, where the density ranges between 368 and 507 kg/m3 due to the different additives and drying techniques, a somewhat linear dependency between tensile index and paper density could be seen.

The strain at break of the handsheets were plotted as a function of their tensile stiffness (Fig. 5). After restrained drying, the strain at break of the handsheets were similar to, or lower than, the level of the reference sheets. Increases in strain at break of papers after restrained drying have previously been reported after addition of agar and gelatin; the highest reported value was approximately 7% after with of 4% gelatin, 4% agar ? cross-linker (Vishtal et al. 2015). In the current study, all of the polysaccharides resulted in increased tensile stiffness values of the handsheets after restrained drying. The largest increases in were seen with alginate, while cationic guar gum or chitosan resulted in less pronounced increases (Table 3). The highest stiffness value obtained was 5.8 kNm/g with 2 wt% alginate ? 30% sorbitol as

3481

softener, i.e. an increase of 1.4 kNm/g from the sprayed reference. As a comparison, a tensile stiffness of 6.4 kNm/g was previously achieved with wet-end additions of carboxymethyl cellulose in combination with a cationic starch (Strand et al. 2017).

The strain at break after unrestrained drying increased moderately with cationic guar gum or chitosan, while the largest increases were seen with alginate (Fig. 5). The largest strain at break value, i.e.

11.3%, was obtained with 2 wt% alginate ? 20 or 30% sorbitol (Table 4). It has been reported that 2 or 4% agar also increased the strain at break of paper by approximately 2% after unrestrained drying (Vishtal and Retulainen 2014a). Addition of 4% gelatin also increased the strain at break of papers after unrestrained drying by about 2%, while further addition of 0.5% cross-linker resulted in an increase of 4.4% (Khakalo et al. 2014). Sequential additions of 4% gelatin and 4% agar ? cross-linker were able to achieve strain at break increases of approximately 5%, but the dosage levels were quite high in this study (Vishtal et al. 2015). In the current study, all of the tensile stiffness values of the sheets were similar to, or lower than, the reference value of 2.4 kNm/g after unrestrained drying. Alginate, chitosan, or cationic guar gum had slight to no effect on the stiffness of handsheets after unrestrained drying, even though noticeable changes were seen in strain at break and tensile index. It has been previously reported that 4% gelatin increased the tensile stiffness slightly of the paper after unrestrained drying, while including a cross-linker made this effect more pronounced (Khakalo et al. 2014). Sequential addition of gelatin and agar resulted in increased stiffness values, from 75 kN/m up to approximately 90 kN/m, after unrestrained drying (Vishtal et al. 2015). It was noted that the results from the preliminary study of polysaccharide model films were not directly transferable to the fiber network after unrestrained drying; chitosan or cationic guar gum did not increase the strain at break significantly, while alginate instead resulted in higher values.

The 2D formability strain of the handsheets after unrestrained drying was tested at 23 and 90 °C. The reference sheets could strain approximately 10% before breaking in the 2D tests (Fig. 6), i.e. about 1% further than in regular tensile testing. When comparing the reference with the reference samples of previously published 2D formability tests, it was clear

123

3482

Cellulose (2019) 26:3473–3487

Fig. 5 Tensile stiffness (kNm/g) versus strain at break (%) of handsheets sprayed with the different polysaccharide solutions.

The paper properties were measured after restrained (R) and unrestrained (UR) drying. The average values with their standard deviations are shown

Table 4 The mechanical properties of handsheets after unrestrained drying Unrestrained drying

Density kg/m3

Tensile index Nm/ g

Tensile stiffness s

kNm/g

s

Strain at break

1D shrinkage

Air permeabi lity

%

%

mL/min

s

s

Reference

398.6

50.6

2.4

2.2

0.1

9.2

0.3

4.3

2394

398

Reference-sprayed

368.4

50.2

1.1

2.4

0.2

9.1

0.3

4.3

2380

129

2% Alginate (? 20% sorbitol)

431.7

69.1

2.5

2.2

0.2

11.3

0.4

5.4

556

54

2% Alginate (? 30°% sorbitol)

382.8

69.0

2.9

2.1

0.2

11.3

0.3

5.3

187

76

4°% Alginate (? 20% sorbitol)

419.2

65.0

3.2

1.9

0.2

10.5

0.3

4.8

377

113

4% Alginate (? 30% sorbitol)

404.0

67.9

2.5

2.2

0.1

10.7

0.2

4.8

316

96

2% Cationic guar gum (? 20% sorbitol)

416.9

56.7

3.5

2.2

0.2

9.9

0.5

4.0

2272

319

2% Cationic guar gum (? 30% sorbitol)

432.3

62.3

3.3

2.4

0.2

9.5

0.3

4.0

2356

128

4% Cationic guar gum (? 20% sorbitol)

411.6

56.9

3.2

2.4

0.2

9.4

0.6

3.9

2083

169

4% Cationic guar gum (? 30% sorbitol)

382.2

60.3

2.3

2.4

0.3

9.4

0.4

4.0

2218

427

2% Chitosan (? 20% sorbitol) 2% Chitosan (? 30% sorbitol)

413.2 389.2

65.4 63.5

4.2 3.9

2.4 2.5

0.2 0.3

8.5 8.7

0.5 0.7

4.0 4.0

3010 3528

283 194

4% Chitosan (? 20% sorbitol)

396.8

60.5

3.0

2.4

0.2

9.7

0.4

3.4

2774

390

4% Chitosan (? 30% sorbitol)

376.2

56.9

4.0

2.3

0.2

9.3

0.5

3.6

2724

274

The average values, as well as their standard deviations (s) are reported. The additions were calculated as wt% of o.d. pulp

that the base paper in the current study had a lower extensibility compared to in previous studies, i.e. 10% compared to 12–13% (Vishtal and Retulainen 2014a; Khakalo et al. 2014; Vishtal et al. 2015). In the current study, only low-consistency (LC) pulp refining had been used, while a combination of high-consistency (HC) and LC refining had been used in the other studies. It is known that combination of HC and LC

123

refining is a good strategy to produce paper with high elongation potential and with high tensile strength simultaneously (Zeng et al. 2013).

Addition of cationic guar gum or chitosan resulted in very slight increases in 2D formability. Alginate, however, resulted in significant increases in 2D formability, with values between 12.3 and 13.1%, i.e. increases of 2.2–3%, at room temperature.

Cellulose (2019) 26:3473–3487

3483

Fig. 6 The 2D formability (%) at 23 °C and 90 °C of handsheets sprayed with the different polysaccharide solutions. The paper properties were measured after unrestrained drying.

The average values with standard deviations are shown. Alg alginate, C-gg cationic guar gum, Chit chitosan. The amount of added sorbitol is also shown in the x-axis legends

Alginate increased the 2D formability to a similar extent as 4% gelatin, and 4% gelatin ? cross-linker, while outperforming addition of 4% agar (Vishtal and Retulainen 2014a; Khakalo et al. 2014). However, it has also been reported that addition of 4% gelatin only increased the 2D formability by approximately 0.5% at room temperature after unrestrained drying, highlighting some inconsistencies (Vishtal et al. 2015).

With alginate, cationic guar gum or chitosan, there were no significant differences in the formability of the sheets as a function of temperature. It has previously been reported that the 2D formability of paper sprayed with agar and/or gelatin does increase with increasing temperature (Vishtal and Retulainen 2014a; Khakalo et al. 2014; Vishtal et al. 2015).

In order to better understand the previously presented results, the measured paper shrinkages were plotted against their corresponding strain at break values after restrained and unrestrained drying (Fig. 7). It was seen that also the handsheets dried under restraint between blotters had shrunk to some extent; between 0.1 and 1.8% 1D shrinkage was measured (Table 3). Even limited paper shrinkage during restrained drying will affect the paper properties, by enhancing the strain at break and lowering the tensile stiffness to some extent. In a previously published study, it was seen that a strain at break of 6.4% could be considered the upper limit of elongation potential from strength increases alone without paper shrinkage (Strand et al. 2017). In a previously reported refining study, it was seen that the strain at break of

papers leveled off at about 5% with increasing refining energy, when the drying shrinkage of the sheets had been minimized (Strand et al. 2018). Also shrinkage during restrained drying needs to be considered and measured when dealing with strain at break values surpassing 6.5%, to ensure that the high values are not a function of unexpected drying shrinkage. Strain at break values of up to 7% after restrained drying have been reported for sheets sprayed with 4% gelatin, 4% agar ? cross-linker, but the paper shrinkage during restrained drying was not reported (Vishtal et al.

2015). When all of the measured 1D shrinkages were combined with their corresponding strain at break values, an almost linear correlation emerged. The correlation indicated that handsheets without any shrinkage should be able to strain 4.6%, which is very close to previously reported values for this pulp after 135 kWh/t of LC-refining (Strand et al. 2018). A linear trend between strain at break and drying shrinkage during unrestrained drying has previously been presented, as a function of sprayed amount of agar (Vishtal and Retulainen 2014a). The current study extends the linear correlation towards lower shrinkage values also.

The 1D shrinkage after unrestrained drying was significantly larger than after restrained drying (Table 4). The 1D shrinkage of the reference sheets was 4.3%. Cationic guar gum and chitosan decreased the shrinkage slightly, and had quite limited effects on the strain at break of the sheets (Fig. 7). The tendency for cationic polysaccharides to decrease paper

123

3484

Cellulose (2019) 26:3473–3487

Fig. 7 Strain at break (%) versus 1D shrinkage (%) of handsheets sprayed with the different polysaccharide solutions. The paper properties were measured after restrained (R) and unrestrained (UR) drying. The average values with standard deviations are shown

shrinkage has previously been studied and reported (Strand et al. 2017). Alginate was the only tested polysaccharide that actively increased paper shrinkage during unrestrained drying, which lead to noticeably higher strain at break values of the handsheets.

The air permeability of the handsheets was measured after restrained and unrestrained drying. After restrained drying, the water spraying had increased the air permeability from 2868 to 4020 mL/min (Table 3).

The large influence of the spraying procedure was, however, not visible after unrestrained drying (Table 4). After restrained drying, all of the polysaccharide additions resulted in decreased air Fig. 8 The air permeability (mL/min) of handsheets sprayed with the different polysaccharide solutions.

The permeability values were measured after restrained and unrestrained drying. The average values with standard deviations are shown. Alg alginate, C-gg cationic guar gum, Chit chitosan. The amount of added sorbitol is also shown in the x-axis legends

123

permeability values (Fig. 8). Alginate lowered the air permeability values of the handsheets significantly.

Chitosan or cationic guar gum did not result in similar decreases. A drastic decrease in air permeability has previously been also reported after addition of agar onto wet sheets; the value decreased by approximately 84% (Vishtal and Retulainen 2014a). In the same study, it was reported that a surface film of agar could be useful in grease-barrier applications due to the hydrophilic nature of the polysaccharide and the dense structure of the surface.

The sprayed top sides of the different handsheets were imaged using a scanning electron microscope

Cellulose (2019) 26:3473–3487

(SEM). It was seen that the handsheets had a much denser surface structure with alginate, compared to with cationic guar gum or chitosan (Fig. 9). The alginate seemed to fill out some of the roughness of the paper surface, which also lowered the air permeability of the fiber network significantly. This was similar to the previously reported effect of agar (Vishtal and Retulainen 2014a). The available results indicate that anionic additives may form a film on top of the sheet after spray addition, while cationic additives may migrate more freely throughout the fiber network, once saturated. This is also in agreement with previous findings that iminated amphiphilic galactoglucomannans formed a film on top of the paper after spray addition, while cationic galactoglucomannans were able to penetrate deeper into the fiber network during impregnation (Lindqvist et al. 2014). The formation of an alginate film on the top side of the paper resulted in

3485

enhanced paper shrinkage, which significantly increased the strain at break and 2D formability strain after unrestrained drying. The shrinkage of the wet alginate film during drying was most likely transferred to the rest of the fiber network causing enhanced paper shrinkage, much like the reported effect of agar (Vishtal and Retulainen 2014a).

Conclusions Model polysaccharide films were prepared from alginate, cationic guar gum, or chitosan. Alginate resulted in very strong and stiff films with low strain at break values, while cationic guar gum and chitosan resulted in significantly weaker and softer films with high strain at break values. The different polysaccharide solutions were sprayed onto wet handsheets, and

Fig. 9 SEM micrographs of the top surfaces of handsheets sprayed with alginate (A, B), cationic guar gum (C), and chitosan (D). All of these handsheets were sprayed with 2% polysaccharide with addition of 20% sorbitol, and subjected to restrained drying

123

3486

the paper properties were measured after restrained and unrestrained drying. Alginate resulted in stiffer and stronger paper than the other tested polysaccharides after restrained drying. Alginate also increased the 2D formability strain of papers after unrestrained drying to a higher extent. Addition of alginate resulted in the formation of a film on the topside of the paper, which decreased the air permeability of the paper significantly and lead to enhanced paper shrinkage.

Out of the tested polysaccharides, alginate was found to be the most promising candidate for future packaging applications due to the fact that it gave strong and stiff model films, enhanced paper shrinkage, effectively lowered the air permeability of the paper, and formed a layer on the topside of the paper.

Acknowledgments Open access funding provided by Abo Akademi University (ABO). This work is a part of the project ExtBioNet, appointed by the Academy of Finland. Special thanks to technology student Richard Sundberg, Academic Lecturer Mari Nurmi at The Laboratory of Paper Coating and Converting, Åbo Akademi University, and PhD Vinay Kumar at The Laboratory of Paper Coating and Converting, Åbo Akademi University (currently with VTT).

Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http:// creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

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PAPERmaking!

O THE PUBLISHERS U S S OF O PAPER TECHNOLOGY INTERNATIONAL FROM

Volume 6, Number 1, 2020

Dynamic soft sensing of organic pollutants in effluent from UMIC anaerobic reactor for industrial papermaking wastewater Yajuan Xing, Zhong Cheng, Shengdao Shan.

With the rapid development of paper industry, the pressure of environmental pollution is going more and more serious. Recently, resource utilization of wastewater by anaerobic digestion has become a feasible way to solve this problem. In order to maintain the safe and efficient production of the process, a novel adaptive soft sensor model was developed to infer the chemical oxygen demand (COD) of paper mill effluent in this paper. First, the principal component analysis technique was performed in this model so as to eliminate the col-linearity between the process variables and accordingly obtain the low-dimensional feature principal component. Then, the least square support vector machine method was used to construct a quantitative regression model between principal component and the effluent COD. Along with it, particle swarm optimization was implemented to search for the best value of the LSSVM model parameters, namely the kernel parameters and the regularization factor. Finally, an online calibration strategy was designed to adapt to the process dynamic changes in an adaptive iterative manner. When the constructed model tested for performances in a full-scale factory, the average relative deviation and maximum deviation are 1.80% and 6.26%, respectively. The experimental results show that this proposed soft sensor model is featured with high accuracy and strong dynamic stability, and it can provide good guidance for COD prediction and optimal control of paper mill wastewater treatment.

Contact information: Xing: Key Laboratory of Recycling and Eco-treatment of Waste Biomass of Zhejiang Province, School of Environment and Resources, Zhejiang University of Science and Technology, Hangzhou 310023 Cheng: School of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Hangzhou 310023 Shan: Key Laboratory of Recycling and Eco-treatment of Waste Biomass of Zhejiang Province, School of Environment and Resources, Zhejiang University of Science and Technology, Hangzhou 310023 IOP Conf. Series: Materials Science and Engineering 490 (2019) 062027 doi:10.1088/1757-899X/490/6/062027 Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence.

The Paper Industry Technical Association (PITA) is an independent organisation which operates for the general benefit of its members – both individual and corporate – dedicated to promoting and improving the technical and scientific knowledge of those working in the UK pulp and paper industry. Formed in 1960, it serves the Industry, both manufacturers and suppliers, by providing a forum for members to meet and network; it organises visits, conferences and training seminars that cover all aspects of papermaking science. It also publishes the prestigious journal Paper Technology International and the PITA Annual Review, both sent free to members, and a range of other technical publications which include conference proceedings and the acclaimed Essential Guide to Aqueous Coating.

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IOP Conference Series: Materials Science and Engineering

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'\QDPLF VRIW VHQVLQJ RI RUJDQLF SROOXWDQWV LQ HIIOXHQW IURP 80,& DQDHURELF UHDFWRU IRU LQGXVWULDO SDSHUPDNLQJ ZDVWHZDWHU To cite this article: Yajuan Xing et al 2019 IOP Conf. Ser.: Mater. Sci. Eng. 490 062027

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SAMSE 2018 IOP Publishing IOP Conf. Series: Materials Science and Engineering 490 (2019) 062027 doi:10.1088/1757-899X/490/6/062027

Dynamic soft sensing of organic pollutants in effluent from UMIC anaerobic reactor for industrial papermaking wastewater Yajuan Xing1, Zhong Cheng2,*, Shengdao Shan3 1

Key Laboratory of Recycling and Eco-treatment of Waste Biomass of Zhejiang Province, School of Environment and Resources, Zhejiang University of Science and Technology, Hangzhou 310023 2 School of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Hangzhou 310023 3 Key Laboratory of Recycling and Eco-treatment of Waste Biomass of Zhejiang Province, School of Environment and Resources, Zhejiang University of Science and Technology, Hangzhou 310023 *Corresponding author e-mail: chengzhong@zust.edu.cn Abstract. With the rapid development of paper industry, the pressure of environmental pollution is going more and more serious. Recently, resource utilization of wastewater by anaerobic digestion has become a feasible way to solve this problem.

In order to maintain the safe and efficient production of the process, a novel adaptive soft sensor model was developed to infer the chemical oxygen demand (COD) of paper mill effluent in this paper. First, the principal component analysis technique was performed in this model so as to eliminate the col-linearity between the process variables and accordingly obtain the low-dimensional feature principal component.

Then, the least square support vector machine method was used to construct a quantitative regression model between principal component and the effluent COD. Along with it, particle swarm optimization was implemented to search for the best value of the LSSVM model parameters, namely the kernel parameters and the regularization factor. Finally, an online calibration strategy was designed to adapt to the process dynamic changes in an adaptive iterative manner. When the constructed model tested for performances in a full-scale factory, the average relative deviation and maximum deviation are 1.80% and 6.26%, respectively. The experimental results show that this proposed soft sensor model is featured with high accuracy and strong dynamic stability, and it can provide good guidance for COD prediction and optimal control of paper mill wastewate treatment.

1. Introduction The paper-making industry is a major water consumer and also a major wastewater discharger.

According to the statistics of the Ministry of Ecology and Environment, In 2015, the total water consumption of the paper-making industry and the paper product industry (4,180 enterprises involved in the statistics) was 11.835 billion tons, and the wastewater discharge was 2.367 billion tons,

Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Published under licence by IOP Publishing Ltd 1

SAMSE 2018 IOP Publishing IOP Conf. Series: Materials Science and Engineering 490 (2019) 062027 doi:10.1088/1757-899X/490/6/062027

accounting for 13.0% of the total industrial wastewater discharge. The chemical oxygen demand (COD) in the discharged wastewater is 335,000 tons, accounting for 13.1% of the total industrial COD emission. In recent years, with the increasing shortage of water resources, production water has become a problem that restricts the development of paper-making enterprises. At present, in order to solve the environmental pollution due to paper-making wastewater and realize resource utilization, biogas production through anaerobic digestion has become a main method. The anaerobic digestion process under the action of microorganisms is featured as multi-factor influence, dynamic variability, complex nonlinearity (Yang Hao et al., 2016), etc. and the mechanism model thereof is difficult to construct, so the real-time operation control and optimization and calibration that affect safe production and effluent water production conditions cannot be realized. The production effectiveness of the industrialization process of anaerobic digestion for paper-making wastewater is often measured by the effluent COD. However, the current COD testing of enterprises is mostly realized by timed manual sampling and laboratory analysis. The test results cannot be obtained till several hours later, so the real-time performance is poor (Xu Lisha et al., 2012). In case that a COD on-line analyzer is installed on site, failure often occurs, resulting in loss of data. And also, the maintenance is difficult and the instrument is expensive(Langergraber et al., 2004; Bourgeois et al., 2010). With the improvement of enterprise automation as well as the deep integration of informationization and industrialization, the methods like pivot element regression, partial least squares regression, neural network, support vector machine and fuzzy logic have been used for the data modeling and operational control of the performance indicators including COD concentration, volatile fatty acid (VFA), dissolved oxygen, suspended solids (SS) concentration and gas production in the process of paper-making wastewater treatment (Bourgeois et al., 2010; Haimi et al., 2013) Choi et al., 2001; Wan et al., 2011; Huang et al., 2015 DĂźrenmatt et al., 2012; Zhou Hongbiao et al., 2017; Liu Lin et al., 2017; Tang Wei et al., 2017). With respect of the method selection, Wan et al. (2011) designed an adaptive fuzzy inference system integrating fuzzy subtractive clustering and PCA technologies, of which the fuzzy subtractive clustering is used to identify the model structure, and PCA is used to reduce the complex collinearity between variables as well as the dimensionality. The model accuracy with this integrated method is higher than that with the BP neural network method in the performance test about the COD and SS concentration prediction of paper-making wastewater. Wang Yao et al.

(2017) chose the LSSVM method to predict the COD and SS concentrations. The results show that the soft-sensor model created by optimizing the LSSVM method parameters via the PSO algorithm has a higher prediction accuracy. The LSSVM method based on minimum structural risk is widely used in soft-sensor modeling because of its features of low dependence on sample data, less parameters to be estimated, and strong generalization ability (Souza et al., 2016; Wang et al., 2015; Fortuna et al., 2007; Liu Bo et al., 2015; Zheng Rongjian et al., 2017). However, the prediction accuracy of the soft-sensor model based on the offline sample data architecture, will gradually decline in the face of dynamic changes in continuous production processes. In order to solve the above problem, this paper proposes an OCS-PCA-PSO-LSSVM soft-sensor method integrating data analysis technology and regression modeling, which can eliminate the complex collinearity between variables and achieve dimensionality reduction via PCA technology; then, implement the LSSVM method to establish the nonlinear relationship between input and output variables, and realize the optimization of LSSVM model parameters by means of PSO; and finally, initiate the online calibration strategy (OCS) in case the prediction deviation of the new sample individual exceeds the set error limit, iteratively updating the soft-sensor model in an adaptive manner.

2. Materials and Methods 2.1. Process and Data Collection With the wastewater anaerobic treatment system of a papermaking mill as the test object of application, the production process is shown in Fig. 1, in which the ascending multistage internal circulation anaerobic reactor UMIC is the main device. The UMIC reactor works based on the principle of granular sludge (Ruggeri et al., 2015; Zhang Yi et al., 2014), namely, the papermaking wastewater is thoroughly mixed with anaerobic microbial sludge after being pumped into the reactor by a lift pump, 2

SAMSE 2018 IOP Publishing IOP Conf. Series: Materials Science and Engineering 490 (2019) 062027 doi:10.1088/1757-899X/490/6/062027

and the organics in the mixture are chemically converted into the gases like methane and carbon dioxide, as well as microbial bacterial plastids under the action of the microorganisms.

Based on the analysis of production behavior and process mechanism of the UMIC device, with the combination of experts’ experience and knowledge as well as the sensitivity analysis of field data, 8 process variables that affect the COD of the treatment system were selected as the input variables of the model, and they are: influent COD/mg•L-1, influent SS/mg•L-1, influent pH, influent flow/m3, influent temperature/°C, circulating pool level/%, effluent pH and effluent temperature/°C, while the output variable of the model is effluent COD/mg•L-1. Two sample data collection methods were adopted, one of which was that the mill’s distributed control system DCS was used to collect 8 process variables, and the other was that the on-site sampling laboratory obtained effluent COD through offline test (Sun Jun et al., 2017). After the collection of the mill’s field operation data from July 2016 to February 2017 was completed, the missing data was directly removed, then the abnormal data was identified and deleted, and finally the initial sample matrix set containing 175 sample individuals was obtained.

1-Bar screener; 2-Blending pond; 3- Preliminary clarifier; 4-Pump; 5- Regulating container; 6-Anaerobic reactor; 7-Cycling wstandpipe; 8- Anoxic pool; 9- The secondary clarifier; 10-Biogas storage tank; 11-Nutrient auto-count pipette Fig 1. Flow chart of anaerobic degradation for paper mill wastewater 2.2. OCS-PCA-PSO-LSSVM Soft-sensor Method 2.2.1. PCA Technology The independent variable matrix X nu p of the obtained initial sample data was recorded, where n is the number of sample individuals, i.e. the sample size, and p is the number of process variables. PCA technology (Jolliffe et al., 2002) was namely to project X from the Euclidean space to the latent vector space of the pivot element.

X = TQ T + E =

d

¦ t k q kT + E

(1)

k=1

Where, t k is the k th extracted pivot element, qk is the load vector used to extract the pivot element, and E is the final residual matrix. In essence, the construction of the PCA latent vector space is to represent most of the dynamic information in the initial process variables in the sample data by extracting d pivot elements ( d d p ) (Sun Jun et al., 2017), of which, the information contribution of the k th pivot element can be calculated according to Formula (2).

Kk

p

Ok / ¦ Ok

(2)

k 1

2.2.2. Soft-sensor Optimization Model PSO-LSSVM The least square support vector machine (LSSVM) is an extension of the standard SVM method (Cristianini et al., 2000), and the main ideas of the algorithm are summarized as follows: 3

SAMSE 2018 IOP Publishing IOP Conf. Series: Materials Science and Engineering 490 (2019) 062027 doi:10.1088/1757-899X/490/6/062027

Suppose the modeling sample data set is {(ti , yi )}in 1 , where, ti Â? R d is the input vector of the i th-dimension pivot element in the latent vector space expanded by the d th-dimension pivot element, and yi Â? R is the target output variable of effluent COD of the papermaking wastewater. In the high-dimension feature space constructed by the nonlinear mapping function M (t ) , the model establishment between the output variable and the input variable is to find the best fitting function: y ( t ) w TM ( t ) b (3) Where, w is the weight coefficient vector to be estimated in the high-dimension feature space, b is the constant deviation term. For the LSSVM method, the parameter estimate in the above formula can be transformed to satisfy the constraint of Formula (4): yi w TM (ti ) b [i , i 1, 2, , n (4) The minimization optimization problem was solved as below: 1 T 1 n min J ( w , b, Č&#x; ) w w J ÂŚ [i2 (5) w ,b ,[ 2 2 i1 In the formula, J is a penalty factor, used to balance the complexity and approximation accuracy of the model, [i is the training error of the i th sample point. The Lagrange multiplier D i is now introduced to transform the above-mentioned constraint optimization problem of the formula into an unconstrained optimization problem: L ( w , b, Č&#x; , ÄŽ ) n (6) J ( w , b, Č&#x; ) ÂŚ D i ( wT M (ti ) b [i yi ) i 1

Using the KKT optimization condition to solve the above formula (Zhou Xinran, 2012), that is, to solve the partial derivatives of w ,bˈ [i and D i , we can obtain: n ­ wL 0 w D iM ( t i ) o ÂŚ ° ww i 1 ° n ° wL 0 o ÂŚDi 0 ° ° wb i 1

(7) Ž ° wL 0 o D J[ , i 1, 2, , n i i ° w[i ° ° wL 0 o w TI (t ) b [ y 0, i 1, 2, , n i i i ° wD ¯ i Eliminating the elements from the above equation set, we will obtain the following linear equation set: ª0 º ªb º ª0 º 1Tv

(8) ÂŤ ÂŤ Âť 1 Âť ÂŤ Âť ÂŹ1v K J I Âź ÂŹÄŽ Âź ÂŹ y Âź

Where, 1v

[1,1, ,1n ]T , Ď [D1 , D 2 , , D n ]T , y [ y1 , y2 , , yn ]T , Kij (ti , t j ) M (ti )T M (t j ) ˈ

iˈj 1, 2, , n ˈand I is the unit matrix. After solving the parameters of D i and b in Formula (8) and via the least square method, the LSSVM model will be obtained as below: yˆ

n

f (t )

ÂŚ D i K ( t , ti ) b

(9)

i 1

2

If the LSSVM model uses the RBF kernel function K (t , ti , V ) exp( t ti V 2 ) , the different values of the kernel function width V and the penalty factor J in Formula (5) will affect the actual performance of the LSSVM model (Zhao et al., 2000). To this end, this paper completes the optimization of the two parameters by taking the minimum of the sum of squared error

4

SAMSE 2018 IOP Publishing IOP Conf. Series: Materials Science and Engineering 490 (2019) 062027 doi:10.1088/1757-899X/490/6/062027 nv

¦ ( yl yˆl )2 between the experimental value yl and the predicted value of the model of the effluent l 1

COD as the objective function, through the particle swarm optimization (PSO) (Kennedy et al., 1995), based on the validation sample set.

2.2.3.Model Parameter Adaptive Correction In order to track the dynamic changes of the production process and maintain the prediction performance of the soft-sensor model in real time, an online calibration strategy (OCS) has been designed to iteratively update the soft-sensor model parameters in an adaptive manner. The basic idea of OCS is that if the established soft-sensor model is applied to the prediction of COD for a new sample individual, when the deviation between the experimental value ynew of the new sample individual and the predicted value yˆ new of the model exceeds the set error limit maxe , namely:

| ynew yˆ new |! maxe

X new ynew

T

y

ynew yˆ new ! maxe

{T , y}

{ X , y}

Tnew {V , J }

Off-line modeling with historical data

X

optimize model parameters

On-line correction with new data samples

(10) To Initiate the iterative update of the soft-sensor model parameters. The specific method is as follows: firstly, the sample individuals with the largest fitting deviation are retrieved from the training sample set and deleted; then, the sample individuals with the highest ranking in the monitoring sample set are transferred into the training sample set; next, the vacancy of the validation sample set is filled, namely, the sampled individuals with the highest ranking among the accumulated predicted sample individuals are transferred into the validation sample set; and finally, the soft-sensor model is re-established based on the newly formed training sample set and the validation sample set, which is namely the OCS - PCA-PSO-LSSVM model.

ŷ yˆ new Fig 2. Structure of the OCS-PCA-PSO-LSSVM soft sensor model With this, the implementation flow of the OCS-PCA-PSO-LSSVM method is shown in Fig. 2.

Firstly, the PCA pre-processing of X nu p = [x1 , x2 , , x p ]T was performed and the pivot element matrix Tnud

[t1 , t 2 , , t d ]T was obtained after the number d of pivot elements had been selected; then, based

on Tnud and the output variable matrix ynu1 [ y1 ,y2 , ,yn ]T of the effluent COD, the nonlinear mapping relationship between them was established with the LSSVM method, while the values of

5

SAMSE 2018 IOP Publishing IOP Conf. Series: Materials Science and Engineering 490 (2019) 062027 doi:10.1088/1757-899X/490/6/062027

model parameters V and J were determined by PSO optimization; and finally, the OCS would be initiated to iteratively update the model in case the prediction deviation of the new sample individual was beyond the set error limit.

3.Results and Discussion 3.1. Model Performance Evaluation Indicator To objectively and independently evaluate the performance of the OCS-PCA-PSO-LSSVM soft-sensor model, the initial sample data set was divided into a training sample set, a validation set, and a test set in time order, of which the training sample set contained 100 sample individuals, used for parameter estimation of the model; the validation sample set contained 50 sample individuals, used for parameter optimization of the model; and the test sample set contained the remaining 25 sample individuals, used for performance evaluation of the model. The performance evaluation indicators include: maximum deviation (MAXE)/mg•L-1, maximum relative deviation (MAXRE)/%, mean absolute deviation (MAE)/mg•L-1, mean relative deviation (MRE)/% ,root mean square error (RMSE) / mg • L-1, standard deviation (STD) / mg • L-1, etc., and their respective definition formula are as follows: (11) MAXE max { yi yˆi } i {1,2, , n}

MAXRE

max {

i {1,2, , n}

yi yˆi yi

} u 100% (12)

1 n ¦ yi yˆi ni1 1 n | yi yˆi | ¦ y u100% ni1 i

MAE MRE RMSE

STD

1 n ¦ ( yi yˆi )2 ni1

1 n (ei e ) 2 ¦ n 1 i 1

(13) (14) (15) (16)

1 n ¦ ei , while yi and ŷi denote the experimental value and predicted ni1 value of the model regarding COD of the i th sample individual, respectively. Among the above Where, ei

yi yˆi , e

statistical performance indicators, MAXE, MRE, RMSE and STD are absolute accuracy indicators, of which, MAXE measures the limit boundary conditions of the model according to the maximum predicted deviation of the sample individuals, and MRE and RMSE measure the accuracy of the model according to the average prediction accuracy of the sample individuals. while STD measures the stability of the model according to the degree of dispersion of the prediction deviation of the sample individuals. Considering the objective difference between the magnitudes of different physical quantities, MAXRE and MRE are relative accuracy indicators. The former measures the deviation of the prediction results based on a single sample individual, and the latter does the same based on the average of sample individuals. The smaller the values of these statistics are, the better the performance of the model will be indicated.

3.2. Experimental Results and Analysis As described in Section 2.2.1 above, in order to satisfy that the pivot element under the OCS-PCA-PSO-LSSVM method contain enough initial variable information, and the cumulative information contribution rate of the dth extracted pivot element is now required to be above 85%.

Based on the information of the eight latent roots of the correlation matrix for the training sample set

6

SAMSE 2018 IOP Publishing IOP Conf. Series: Materials Science and Engineering 490 (2019) 062027 doi:10.1088/1757-899X/490/6/062027

of papermaking wastewater, when the 6th pivot element is extracted during calculation, namely, d 6 , the cumulative information contribution rate is 92.63%. Thus, the six pivot element are determined as the input vectors of the subsequent PSO-LSSVM model.

As described in Section 2.2.2 above, the optimization process for the algorithm of parameters J and V PSO under the LSSVM method is shown in Figs. 3 and 4 after the RBF radial basis kernel function was selected, and the population particle number was set at 30, the minimum inertia weight was wmin =0.01, the maximum inertia weight was wmin =0.99, the particle maximum velocity was

vmax

2 , the particle minimum velocity was vmin

-2 , and the learning factor was c1

c2

2 and

the maximum number of iterations was 100. When J =0.3356 and V =2.2026, the RMSE of the objective function observation sample set reached the minimum, thereby it was determined as the optimal value of the parameter under the LSSVM method.

Fig 3. Regularization factor optimizing curve using PSO

Fig 4. Kernel parameter optimizing curve using PSO After the optimization for the input variable and parameter of the model was completed, the OCS-PCA-PSO-LSSVM model was applied to the test sample set to detect the model’s generalization ability. Table 1 shows the test results of different performance indicators for the three models of OCS-PCA-PSO-LSSVM, PCA-PSO-LSSVM and SVM. It may be observed from the table that the values of the maximum deviation, the maximum relative deviation, the average absolute deviation, the average relative deviation, the root mean square error, and the standard deviation of the OCS-PCA-PSO-LSSVM model are significantly lower than the corresponding results of the PCA-PSO-LSSVM model and the SVM model. Where, compared with the PCA-PSO-LSSVM model, the MAXE of the OCS-PCA-PSO-LSSVM model decreased by 39.15%, the MRE decreased by 25.00%, and the STD decreased by 29.89%. The reason for this is that when the PCA-PSO-LSSVM model predicted the 2nd, 10th, 20th, and 21st sample individuals in the test sample set, their prediction deviations were greater than their respective maximum fitting deviation the training sample set, so the OCS strategy was initiated 4 times to perform the iterative update of the model, therefore, from the 2nd 7

SAMSE 2018 IOP Publishing IOP Conf. Series: Materials Science and Engineering 490 (2019) 062027 doi:10.1088/1757-899X/490/6/062027

sample individual of the test sample set containing 25 sample individuals, and the predicted value of the model was different from the predicted value of the PCA-PSO-LSSVM model without the OCS strategy integrated, which was generally reflected as the deviation tends to be small, thus achieving dynamic adjustment and optimization of the model.

Tab. 1 Model performances comparison on the testing data set MAXE MAXRE MAE MRE RMSE STD Methods -1 -1 -1 /mg路L /% /mg路L /% /mg路L /mg路L-1 SVM

54.39

7.82

18.62

2.58

22.96

13.71

PCA-PSO-LSSVM

51.09

7.53

17.37

2.40

21.57

13.05

OCS-PCA-PSO-LSSVM

31.09

6.26

12.31

1.80

15.23

9.15

To visually compare the prediction performance of the above three model methods, the experimental values and predicted values of COD of 25 sample individuals in the test sample set are plotted in Fig.5. Through observation of the figure, it can be seen that compared with the PCA-PSO-LSSVM and SVM model methods, the COD results on each sample individual predicted with the OCS-PCA-PSO-LSSVM model method are more closely to their respective experimental values, thereby indicating that the OCS- The PCA-PSO-LSSVM model method has better generalization prediction ability and stronger dynamic stability.

1300 Analysis Value SVM PCA-PSO-LSSVM OCS-PCA-PSO-LSSVM

1200

COD/mg.L-1

1100 1000 900 800 700 600 500 400

0

5

10

15

20

25

Observation Number

Fig 5. Prediction results of COD on the generalization data set 4. Conclusions Made in China 2025 clearly pointed out "taking the deep integration of informatization and industrialization as the main line." Based on the safe and healthy management and high-efficiency production requirements in the anaerobic treatment process of papermaking wastewater, this paper focuses on the study of the soft-sensor prediction and dynamic optimization of the model based on the data-driving effluent COD as the water quality indicator, to promote the transformation of the paper industry from extensive development to sustainable development, from the end treatment to the resource utilization, promoting the intelligent management and control of the production process, the main conclusions are as follows: 1) In order to adapt to the structure of anaerobic reactor and the multivariable, nonlinear, time-varying features of the parameters, as well as the special complexity of papermaking wastewater process and the uncertainty of production behavior, the soft-sensor method integrating the modern data analysis technology and intelligent regression model have been developed and designed, which not

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SAMSE 2018 IOP Publishing IOP Conf. Series: Materials Science and Engineering 490 (2019) 062027 doi:10.1088/1757-899X/490/6/062027

only effectively reduces the complex collinearity between variables, but also reduces the spatial dimension of the model, and the prediction accuracy and dynamic stability of the model are significantly improved, achieving the overall improvement and breakthrough of the model performance by virtue of the integration advantages.

2) Data-driving soft-sensor model method: As the time series data continues to increase, the prediction accuracy of the model based on long-term historical data will decrease. Taking the actual industrial process as the background, combined with the dynamic change characteristics of the process, the method can adaptively iteratively update the model parameters through deviation feedback, and maintain the generalization performance of the soft-sensor model in real time, thus ensuring the continuous efficient and stable operation of the equipment, and monitoring the energy conservation and emission reduction as well as sustainable development of the enterprise.

Acknowledgements Financial supports of this work by National Natural Science Foundation of China (U1609214), Major Projects for Science and Technology Development of Zhejiang Province, China (2015C02037), Zhejiang Science and Technology Program key projects, China (2017C03010), and Zhejiang Province Research Project of Public Welfare Technology Application (2016C33105).

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[17]Wan Jinquan, Huang Mingzhi, Ma Yongwen, et al. 2011. Prediction of effluent quality of a paper mill wastewater treatment using an adaptive network-based fuzzy inference system[J]. Applied Soft Computing, 11: 3238-3246 [18]Wang Wenchuan, Liu Xinggao.2015.Melt index prediction by least squares support vector machines with an adaptive mutation fruit fly optimization algorithm[J]. Chemometrics and Intelligent Laboratory Systems, 141: 79-87 [19]Wang Yao, Xu Liang, Yin Wenzhi, et al. 2017. Soft-sensor Modeling of Papermaking Wastewater Treatment Process Based on ANN and LSSVR[J]. Transactions of China Pulp and Paper, 32(1): 50-54 [20]Xu Lisha, Qian Xiaoshan. 2012. A Study on Soft-sensor of Effluent COD Based on MUTATION CPSO ALGORITHM[J]. Chinese Journal of Environmental Engineering, 6: 1455-1458 [21]Yang Hao, Mo Weilin, Xiong Zhixin, et al. 2016. Soft-sensor Modeling of Papermaking Wastewater Treatment Process Based on RPLS[J]. Paper China, 35(10): 31-35 [22]Zhang Wei, Liu Min, Chen Wei, et al. 2014. Influence of External Circulation on the Operation Effect of IC Reactors[J]. Journal of Chemical Industry and Engineering, 65: 2329-2334 [23]Zhao Huiru, Huang Guo, Yan Ning. 2018.Forecasting energy-related CO2 emissions employing a novel SSA-LSSVM model: considering structural factors in China[J]. Energies, 11: 781-802.

[24]Zheng Rongjian, Pan Feng. 2017. Modeling for Concentration Prediction of Glutamic Acid Fermentation Products based on PLS-LSSVM[J]. Journal of Chemical Industry and Engineering, 68: 976-983 [25]Zhou Hongbiao, Qiao Junfei. 2017. Application of Hybrid Multi-objective Particle Swarm Optimization Algorithm in Optimal Control of Wastewater Treatment Process[J]. Journal of Chemical Industry and Engineering, 68: 3511-3521 [26]Zhou Xinran. 2012. Research on online Modeling and Control Method Based on Least Squares Support Vector Machine[D]. Changsha: Hunan University, 19-21

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PAPERmaking!

O THE PUBLISHERS U S S OF O PAPER TECHNOLOGY INTERNATIONAL FROM

Volume 6, Number 1, 2020

Effect of Recycling Number on the Fluorescence Reduction of Fluorescent Whitening Agents in White Wastepapers 2

2

1

1

2

Ji Young Lee , Chul Hwan Kim , Hae Min Jo , Kyung Min Kim and Su Ho Kim .

White wastepaper is a very important resource in the Korean paper industry. However, its use is limited because it contains fluorescent whitening agents (FWAs). To improve the use of recycled white wastepaper, FWAs should be removed. The first step in eliminating FWAs from wastepaper is to analyze the behavior of FWAs from wastepaper during the recycling process. In this study, the effect of recycling on FWA detachment from white wastepaper and the distribution change of FWAs in the sheet was investigated.

Disulfo-,tetrasulfo- and hexasulfo-FWAs commonly found in paper were prepared and recycled many times through a laboratory process. After each round of recycling, the optical properties and fluorescence index of the sheet were measured, and the fluorescence reduction was calculated as an indicator, which represents the FWA detachment from wastepaper, using fluorescence indices before and after recycling. The FWA distribution in the paper cross section was observed using a CLSM. Disulfo-FWA exhibited a lower fluorescence reduction and even distribution in the paper cross section; however, surface-treating FWAs, including tetrasulfo-FWA, and hexasulfo-FWA, extensively desorbed from the paper during the recycling process. The surface-treating FWAs showed similar distributions in paper cross section after the recycling because of their readsorption on the fibers. Therefore, surface-treating FWAs can be detached easily compared with internal FWAs, and some detached FWAs can re-adsorb on cellulosic fibers during the recycling process.

Contact information: 1 Department of Forest Products, Gyeongsang National University, Jinju-daero, 501, Jinju, 52828, Republic of Korea.

2 Department of Environmental Materials Science/IALS, Gyeongsang National University, Jinju-daero, 501, Jinju, 52828, Republic of Korea.

Journal of Korea TAPPI, Vol. 51. No. 2, 2019, 49-57p, ISSN (Print): 0253-3200 http://dx.doi.org/10.7584/JKTAPPI.2019.04.51.2.49

The Paper Industry Technical Association (PITA) is an independent organisation which operates for the general benefit of its members – both individual and corporate – dedicated to promoting and improving the technical and scientific knowledge of those working in the UK pulp and paper industry. Formed in 1960, it serves the Industry, both manufacturers and suppliers, by providing a forum for members to meet and network; it organises visits, conferences and training seminars that cover all aspects of papermaking science. It also publishes the prestigious journal Paper Technology International and the PITA Annual Review, both sent free to members, and a range of other technical publications which include conference proceedings and the acclaimed Essential Guide to Aqueous Coating.

Page 1 of 10

Article 5 – FWAs and Recycling

Journal of Korea TAPPI Vol. 51. No. 2, 2019, 49-57p ISSN (Print): 0253-3200 Printed in Korea

http://dx.doi.org/10.7584/JKTAPPI.2019.04.51.2.49

Effect of Recycling Number on the Fluorescence Reduction of Fluorescent Whitening Agents in White Wastepapers Ji Young Lee, Chul Hwan Kimⲵ, Hae Min Jo1, Kyung Min Kim1 and Su Ho Kim Received March 5, 2019; Received in revised form April 3, 2019; Accepted April 8, 2019

"#453"$5 White wastepaper is a very important resource in the Korean paper industry. However, its use is limited because it contains fluorescent whitening agents (FWAs). To improve the use of recycled white wastepaper, FWAs should be removed. The first step in eliminating FWAs from wastepaper is to analyze the behavior of FWAs from wastepaper during the recycling process. In this study, the effect of recycling on FWA detachment from white wastepaper and the distribution change of FWAs in the sheet was investigated. Disulfo-, tetrasulfo- and hexasulfo-FWAs commonly found in paper were prepared and recycled many times through a laboratory process. After each round of recycling, the optical properties and fluorescence index of the sheet were measured, and the fluorescence reduction was calculated as an indicator, which represents the FWA detachment from wastepaper, using fluorescence indices before and after recycling. The FWA distribution in the paper cross section was observed using a CLSM. Disulfo-FWA exhibited a lower fluorescence reduction and even distribution in the paper cross section; however, surface-treating FWAs, including tetrasulfo-FWA, and hexasulfo-FWA, extensively desorbed from the paper during the recycling process. The surface-treating FWAs showed similar distributions in paper cross section after the recycling because of their readsorption on the fibers. Therefore, surface-treating FWAs can be detached easily compared with internal FWAs, and some detached FWAs can re-adsorb on cellulosic fibers during the recycling process.

Keywords: Fluorescent whitening agent (FWA), white wastepaper, recycling, fluorescence reduction, distribution, re-adsorption

• Department of Environmental Materials Science/IALS, Gyeongsang National University, Jinju-daero, 501, Jinju, 52828, Republic of Korea 1 Department of Forest Products, Gyeongsang National University, Jinju-daero, 501, Jinju, 52828, Republic of Korea † Corresponding Author: E-mail: jameskim@gnu.ac.kr

J. of Korea TAPPI Vol.51 No.2 Mar.-Apr. 2019

49

Effect of Recycling Number on the Fluorescence Reduction of Fluorescent Whitening Agents in White Wastepapers

*OUSPEVDUJPO

tachment from white wastepaper and the distribution change of FWAs in the sheet was investigated.

The most important advantage of paper is its re1)

Three types of papers were prepared, dyed with

cyclability. Paper is recycled as a raw material for

various FWAs, disintegrated, and again made into

the manufacture of other paper products, and re-

handsheets. The recycling rounds were repeated up

cycled wastepaper is classified into many groups

to ten times for D-FWA and five times for T-FWA

such as old newspapers (ONPs), old corrugated

and H-FWA. After each round of recycling, the

containers (OCCs), old magazines (OMGs), and

CIE whiteness, ISO brightness, and fluorescence

mixed office waste (MOW). Paperboard-grade

index of the handsheet were measured, and the

products, including linerboard and white-lined

fluorescence reduction was calculated as an indi-

chipboard, have been manufactured from recycled

cator, which represents the FWA detachment from

wastepaper, and the production of paperboard

wastepaper, using the fluorescence indices before

grade products accounts for approximately 50% of

recycling and after each round of recycling. Fi-

2)

nally, the distribution of FWAs in the cross section

Therefore, recycled wastepaper is a very important

of the handsheet was observed using a confocal

resource for the Korean paper industry.

laser scanning microscope (CLSM).

the paper products produced in South Korea.

Among all wastepaper, the white varieties, including OMGs, MOW, and white ledger paper, are widely used to produce white-lined chipboard,

.BUFSJBMT BOE .FUIPET

which is used for food packaging, pharmaceuticals, detergents, and other products.3) White wastepaper

.BUFSJBMT

contains fluorescent whitening agents (FWAs),

Three types of FWAs, including disulfo-FWA

which are subject to safety regulation in chipboard

(D-FWA), tetrasulfo-FWA (T-FWA), and hexas-

mills.4) In addition, costumers worry about the

ulfo-FWA (H-FWA) are commercially available

toxicity of FWAs in recycled paper products. Be-

products. Bleached softwood kraft pulp (Sw-BKP)

cause it is inevitable to use white wastepaper to

and bleached hardwood kraft pulp (Hw-BKP) were

manufacture paperboard in the Republic of Korea,

provided by Moorim Paper (Jinju, Republic of Ko-

it is necessary to develop a method to remove or

rea), and used to make handsheets that were dyed

control FWAs originating from white wastepaper.

with D-FWA. Non-sized fine paper with a gram-

The FWAs used in the paper industry are classi-

mage of 95 g/m2 was used as the base paper for

fied into three groups according to the level of sul-

surface sizing with T-FWA or H-FWA. Oxidized

fonic acid present: disulfo-FWA (D-FWA), tetra-

starch, which was provided by Daesang (Icheon,

sulfo-FWA (T-FWA), and hexasulfo-FWA

Republic of Korea), was used for surface sizing.

(H-FWA).5,6) FWAs are used in the papermaking process because FWAs have their own affinity to cellulosic fibers and wide-ranging solubility in

4UPDL QSFQBSBUJPO BOE NBOVGBDUVSF PG QBQFS EZFE XJUI '8"

aqueous solutions.5) Therefore, papermakers should

Sw-BKP and Hw-BKP were beaten to 450Âą5 mL

analyze the type of FWA for understanding FWA

CSF using a laboratory valley beater (Daeil Ma-

detachment and distribution change during the re-

chinery Co. Ltd., Daejeon, Republic of Korea). The

7)

cycling process.

In this study, the effect of recycling on FWA de-

50

íŽ„í”„ăƒťě˘…ě?´ę¸°ěˆ 51(2) 2019

pulp samples were mixed in a ratio of 2:8 (SwBKP:Hw-BKP). The mixed pulp slurry was then

Ji Young LeeăƒťChul Hwan KimăƒťHae Min JoăƒťKyung Min KimăƒťSu Ho Kim

diluted to a 0.5% consistency for handsheet prepa-

Korea). The topside of a never-sized sheet of paper

2

ration. Handsheets with a grammage of 100Âą5 g/m

was surface-sized, and the paper was then dried in

were produced according to TAPPI T205 sp-06

an air dryer for 150 s. To prevent the surface-sized

“Forming handsheets for physical tests of pulp�

paper from curling, it was passed through a cylin-

after D-FWA was added to the pulp slurry and

der dryer twice at 120℃. After the topside of the

mixed for 2 min at 600 rpm. The addition percent-

base paper was surface-sized, the bottom side of

ages of D-FWA were kept at 0.4%, 0.8%, and 1.2%

the paper underwent the same treatment. The final

of the oven-dried fibers. The handsheets were wet

pickup weight was controlled at 2.0 to 2.5 g/m2 for

pressed at 345 kPa for 5 min and then dried at

each side. The surface-sized paper was conditioned

120℃ using a laboratory wet press (model 326;

at 23℃ and 50% RH before analysis.

Wintree Corporation, Japan) and a cylinder dryer (Daeil Machinery Co. Ltd., South Korea), respec-

Figure 1 shows a flow diagram of the preparation of model paper containing FWAs.

tively. The prepared handsheets were conditioned at 23℃ and 50% RH, and then analyzed.

4VSGBDF TJ[JOH PG QBQFS XJUI B TUBSDI TPMVUJPO UIBU JODMVEFE '8"T

4JNVMBUJPO PG UIF SFDZDMJOH OVNCFS BOE NFBTVSFNFOU PG PQUJDBM QSPQFSUJFT PG UIF NPEFM QBQFS USFBUFE XJUI '8"T The first round of recycling was performed by the

Preparation of the starch solution and surface

disintegration of paper dyed with FWAs followed

sizing were conducted in the same manner as de-

by subsequent handsheet preparation.7) The disin-

8,9)

The 10% starch

tegration of paper dyed with FWAs was carried out

solution was made by cooking oxidized starch at

at a 2% level using a standard disintegrator;

90℃ to 95℃ for 30 min. After the temperature of

subsequently, handsheets with a grammage of

the solution reached approximately 50℃, T-FWA

100Âą5 g/m2 were made from the disintegrated pulp

or H-FWA was added, and the resulting solution

according to TAPPI T205 sp-06 “Forming hand-

was mixed for 30 min. The addition of the FWAs

sheets for physical tests of pulp�. The handsheets

was kept at 10% and 20% based on the oven-dried

were wet pressed at 345 kPa for 5 min and dried at

starch.

120℃ in a laboratory wet press and in a cylinder

scribed in our previous studies.

The surface-sizing process was conducted using

dryer, respectively. After each round of recycling,

a rod coater (HT-BC-ST, Hantech, Republic of

the handsheets were conditioned at 23℃ and

Fig. 1. Preparation of FWA-treated paper with (a) internal- and (b) surface-treating FWAs. J. of Korea TAPPI Vol.51 No.2 Mar.-Apr. 2019

51

Effect of Recycling Number on the Fluorescence Reduction of Fluorescent Whitening Agents in White Wastepapers

50% RH; and then, their CIE whiteness, ISO

D-FWA was added into the stock mix itself,

brightness, and fluorescence indices were mea-

whereas T-FWA and H-FWA were used on a lab-

sured. Here, the fluorescence index was deter-

oratory coater for surface-sizing with oxidized

mined from the CIE whiteness measurements un-

starch. Fig. 2 shows the CIE whiteness and the ISO

der a D65 illuminant. The fluorescence reduction

brightness values of the paper containing D-FWA

from the paper dyed with FWAs was calculated as

as a function of the number of recycling rounds.

an indicator, which represents the FWA detach-

The initial CIE whiteness and ISO brightness val-

ment from paper, using the fluorescence indices

ues of the paper were proportional to the addition

before recycling and after each round of recycling.7)

level of D-FWA.10) When the addition of D-FWA

The distribution of FWAs in the cross section of the

was more than 0.8%, the CIE whiteness of the pa-

paper was observed using a CLSM (JP/FW 1000,

per was more than 120% and the ISO brightness of

9)

Olympus, Japan).

Fluorescence reduction =

the paper was more than 95%. As the recycling was FI before − FI after FI before

carried out, the optical properties of the handĂ—100

[1]

sheets exponentially decreased.

Figs. 3 and 4 show the CIE whiteness and the ISO

where FIbefore is the initial fluorescence index in-

brightness values of the paper that was sur-

duced by CIE whiteness under D65 illumination

face-sized with T-FWA or H-FWA. Before recy-

before recycling, and FIafter is the fluorescence in-

cling, the paper surface-sized with H-FWA

dex induced by CIE whiteness under D65 illumina-

showed higher optical properties than the paper

tion after each round of recycling.

that was surface-sized with T-FWA.9) As the recycling was performed, the CIE whiteness and ISO brightness of the handsheet exponentially de-

3FTVMUT BOE %JTDVTTJPO

creased. Compared to D-FWA, T-FWA, and H-FWA showed a higher reduction in the optical

&GGFDU PG SFDZDMJOH PO PQUJDBM QSPQFSUJFT PG QBQFS USFBUFE XJUI '8"T

properties irrespective of the lower number of re-

Three types of papers were prepared using

highest reduction in the optical properties among

D-FWA, T-FWA, and H-FWA solutions. The

cycling rounds. In addition, H-FWA showed the the FWAs used in this study.

Fig. 2. CIE whiteness (left) and ISO brightness (right) of the paper containing D-FWA as a function of the number of recycling rounds.

52

íŽ„í”„ăƒťě˘…ě?´ę¸°ěˆ 51(2) 2019

Ji Young LeeăƒťChul Hwan KimăƒťHae Min JoăƒťKyung Min KimăƒťSu Ho Kim

Fig. 3. CIE whiteness (left) and ISO brightness (right) of the paper that was surface-treated with T-FWA as a function of the number of recycling rounds.

Fig. 4. CIE whiteness (left) and ISO brightness (right) of the paper that was surface-treated with H-FWA as a function of the number of recycling rounds.

&GGFDU PG SFDZDMJOH PO UIF GMVPSFTDFODF JOEFY BOE GMVPSFTDFODF SFEVDUJPO JO UIF QBQFS USFBUFE XJUI '8"T

initial fluorescence index of the paper dyed with

FWA addition improves the optical properties of

the handsheet decreased, which means that

paper by absorbing more UV light and emitting

D-FWA was desorbed from the paper. The fluo-

11)

D-FWA was proportional to the addition level of D-FWA. After recycling, the fluorescence index of

The fluorescence emission can be

rescence reduction of D-FWA logarithmically in-

determined by measuring the fluorescence indices

creased as a function of the number of recycling

of whiteness or brightness.12) In this study, the

rounds. However, the fluorescence reduction of

fluorescence index of whiteness under the D65 il-

D-FWA did not exceed 25% even though the recy-

luminant was measured to identify the existence of

cling processes were performed ten times.

fluorescence.

FWAs in the handsheets. The fluorescence reduc-

Figs. 6 and 7 show the fluorescence indices and

tion was calculated using the fluorescence indices

the fluorescence reduction in the paper surface-

before recycling and after each round of recycling.

sized with T-FWA or H-FWA. The fluorescence

Fig. 5 shows the fluorescence index and fluores-

indices of the paper decreased as the number of

cence reduction for paper dyed with D-FWA. The

recycling rounds increased. As the number of J. of Korea TAPPI Vol.51 No.2 Mar.-Apr. 2019

53

Effect of Recycling Number on the Fluorescence Reduction of Fluorescent Whitening Agents in White Wastepapers

Fig. 5. Fluorescence index (left) and fluorescence reduction (right) for the paper containing D-FWA as a function of the number of recycling rounds.

Fig. 6. Fluorescence index (left) and fluorescence reduction (right) for the paper surface-sized with T-FWA as a function of the number of recycling rounds.

Fig. 7. Fluorescence index (left) and fluorescence reduction (right) for the paper surface-sized with H-FWA as a function of the number of recycling rounds. recycling processes increased to five, the T-FWA

duction varied according to the type of FWA used.

and H-FWA reduction logarithmically increased

The fluorescence reduction of T-FWA showed al-

together. However, the maximum fluorescence re-

most 50% when the paper was surface-sized with

54

펄프・종이기술 51(2) 2019

Ji Young LeeăƒťChul Hwan KimăƒťHae Min JoăƒťKyung Min KimăƒťSu Ho Kim

T-FWA and recycled five times. H-FWA exhibited almost a 75% fluorescence reduction after five recycling processes. These results corresponded to the differences in the optical properties as a function of the number of recycling rounds.

The D-FWA reagent adsorbs on the cellulosic fi5)

&GGFDU PG SFDZDMJOH PO UIF '8" EJTUSJCVUJPO GSPN UIF DSPTT TFDUJPO PG UIF QBQFS The fluorescence emission images from the cross section of the paper were captured by CLSM to analyze the effect of recycling on the distributions of

bers via hydrogen bonding. However, T-FWA and

FWAs before and after recycling. Fig. 8 shows the

H-FWA are delivered to the surface of the paper

D-FWA distribution before and after the recycling

by starch or other carrier chemicals, and there are

process. The D-FWA was distributed evenly in the

no chemical bonds formed between T-FWA or

cross sections of the paper before recycling, and

8)

H-FWA and the cellulosic fibers. When white

the initial distribution of D-FWA was maintained

wastepaper containing FWAs was recycled, the

until four rounds of recycling. Figs. 9 and 10 show

starch or carrier chemicals can be extracted from

T-FWA and H-FWA distributions before and after

the wastepaper with T-FWA or H-FWA. However,

the recycling process. The T-FWA and H-FWA

D-FWA was not intentionally extracted from the

reagents were located on both surfaces of the pa-

paper because it was attached to the cellulose fi-

per, which means that T-FWA and H-FWA had a

bers more strongly than T-FWA and H-FWA.

high level of surface holdout.8) However, T-FWA

Therefore, we concluded that D-FWA showed a

and H-FWA were considerably desorbed from the

much lower fluorescence reduction than T-FWA

paper, as the recycling process was preceeded, as

and H-FWA.

shown in Figs. 6 and 7. Both T-FWA and H-FWA showed an especially similar distribution with that of D-FWA after three rounds of recycling.

Fig. 8. D-FWA distribution in the cross section of the paper containing 0.8% D-FWA before (left), and after (right) four rounds of recycling.

Fig. 9. T-FWA distribution in the cross section of the paper surface-sized with 10% T-FWA before (left), and after (right) three rounds of recycling.

J. of Korea TAPPI Vol.51 No.2 Mar.-Apr. 2019

55

Effect of Recycling Number on the Fluorescence Reduction of Fluorescent Whitening Agents in White Wastepapers

Fig. 10. H-FWA distribution in the cross section of the paper surface-sized with 10% H-FWA before (left), and after (right) three rounds of recycling.

The distribution changes in T-FWA and H-FWA

chemical bonds formed between T-FWA or

can be explained by re-adsorption. When T-FWA

H-FWA, and the cellulosic fibers. Therefore, the

and H-FWA were extracted from the paper that

D-FWA was possibly not extracted from paper be-

had been surface-sized with them, the FWAs

cause it was attached to the cellulose fibers more

stayed soluble in the stock. As the contact time

strongly than T-FWA and H-FWA.

between FWAs and the cellulosic fibers increased,

Finally, we concluded that surface-treating

some of the detached FWAs re-adsorbed on the

FWAs can be detached easily compared with inter-

cellulosic fibers because of the sulfonic acids pres-

nal FWA and some of the detached FWAs re-ad-

ent on a FWA molecule.

sorbed on the cellulosic fibers during the recycling process.

$PODMVTJPOT "DLOPXMFEHFNFOU D-FWA exhibited a much lower fluorescence reduction than T-FWA and H-FWA. The CIE white-

This work was supported by a grant from the

ness and ISO brightness of the paper containing

National Research Foundation of Korea (NRF)

D-FWA decreased by less than those of the papers

funded by the Korean government (MSIP; No.

containing T-FWA and H-FWA reagents when the

NRF-2015R1A2 A2A01006463).

number of recycling processes increased.

The D-FWA was distributed evenly in the cross section of the paper before recycling, and the ini-

-JUFSBUVSF $JUFE

tial distribution of D-FWA was maintained until four rounds of recycling. However, T-FWA and

1. Ahn, J. H. and Seo, Y. B., Recycling of waste-

H-FWA were significantly detached from the pa-

paper as countermeasure of climate change,

pers but showed a similar distribution as that of D-FWA when the recycling process was carried out because of re-adsorption.

The D-FWA adsorbed on the cellulosic fibers via hydrogen bonding. However, T-FWA and H-FWA

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3. Kiviranta, A., Paperboard grades, In Paper

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Science and Technology Book Series, Vol. 18, Ch. 2, GA, USA, pp. 54-72 (1997).

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board by ion-pairing high-performance liquid

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J. of Korea TAPPI Vol.51 No.2 Mar.-Apr. 2019

57

PAPERmaking!

O THE PUBLISHERS U S S OF O PAPER TECHNOLOGY INTERNATIONAL FROM

Volume 6, Number 1, 2020

Do Novel Wooden Composites Provide an Environmentally Favorable Alternative for Panel-type Furniture? a,b

c

a

a

Sidan Li , Yuan Yuan , Jinman Wang , and Minghui Guo .

The environmental performance was assessed for a wardrobe made from hybrid modified ammonium lignosulfonate/wood fiber composites (HWC). The HWC wardrobe system involved four subsystems, namely the raw materials supply, energy consumption, wardrobe manufacturing, and transportation. A comparative life cycle assessment of a wardrobe built from conventional medium-density fiberboard with three primary damage categories was also performed. The results suggested that the HWC composites were a more sustainable material compared with conventional boards. The raw materials supply and energy consumption influenced the three primary damage categories. Climate change on human health, particulate matter formation, fossil depletion, and human toxicity had a dominant contribution to the overall environmental impact. Also, a sensitivity analysis was performed with a focus on using wood waste as a raw material and on the different conditions for the modification of lignosulfonate for manufacturing HWC. The results indicated that the use of wood waste and an appropriate amount of unmodified lignosulfonate as a binder aids in efficient HWC production for wardrobes. These results can help to improve HWC wardrobe technology and in choosing the appropriate wardrobe system.

Contact information: a: Key Lab of Bio-based Material Science and Technology of Ministry of Education, Material Science and Engineering College, Northeast Forestry University, Harbin 150040, China. b: Heilongjiang Bayi Agricultural University, Daqing 163319, China. c: Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing 163319, China.

BioResources 14(2), 2740-2758.

DOI: 10.15376/biores.14.2.2740-2758

The Paper Industry Technical Association (PITA) is an independent organisation which operates for the general benefit of its members – both individual and corporate – dedicated to promoting and improving the technical and scientific knowledge of those working in the UK pulp and paper industry. Formed in 1960, it serves the Industry, both manufacturers and suppliers, by providing a forum for members to meet and network; it organises visits, conferences and training seminars that cover all aspects of papermaking science. It also publishes the prestigious journal Paper Technology International and the PITA Annual Review, both sent free to members, and a range of other technical publications which include conference proceedings and the acclaimed Essential Guide to Aqueous Coating.

Page 1 of 20

Article 6 – Wood Panel

PEER-REVIEWED ARTICLE

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Do Novel Wooden Composites Provide an Environmentally Favorable Alternative for Panel-type Furniture?

Sidan Li,a,b Yuan Yuan,c Jinman Wang,a and Minghui Guo a,* The environmental performance was assessed for a wardrobe made from hybrid modified ammonium lignosulfonate/wood fiber composites (HWC).

The HWC wardrobe system involved four subsystems, namely the raw materials supply, energy consumption, wardrobe manufacturing, and transportation. A comparative life cycle assessment of a wardrobe built from conventional medium-density fiberboard with three primary damage categories was also performed. The results suggested that the HWC composites were a more sustainable material compared with conventional boards. The raw materials supply and energy consumption influenced the three primary damage categories. Climate change on human health, particulate matter formation, fossil depletion, and human toxicity had a dominant contribution to the overall environmental impact. Also, a sensitivity analysis was performed with a focus on using wood waste as a raw material and on the different conditions for the modification of lignosulfonate for manufacturing HWC. The results indicated that the use of wood waste and an appropriate amount of unmodified lignosulfonate as a binder aids in efficient HWC production for wardrobes. These results can help to improve HWC wardrobe technology and in choosing the appropriate wardrobe system.

Keywords: Wooden furniture; HMAL/WF composites (HWC); Medium-density fiberboard (MDF); Life cycle assessment (LCA); Sustainability Contact information: a: Key Lab of Bio-based Material Science and Technology of Ministry of Education, Material Science and Engineering College, Northeast Forestry University, Harbin 150040, China; b: Heilongjiang Bayi Agricultural University, Daqing 163319, China; c: Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing 163319, China; * Corresponding author: gmh1964@126.com

INTRODUCTION The world is facing challenges from social, environmental, and economic areas.

Furniture products are household necessities that are used in the daily lives of people.

Currently, this industry accounts for a considerable portion of global trade (Azizi et al.

2016). In 2015, the world furniture market was worth 455 billion US dollars, while the volume of export trade reached 52.8 billion US dollars. Furniture products have become promising and one of the leading export merchandises in China (Wang et al. 2016).

Sustainable development of this industry is a major concern in developed and developing countries (González-García et al. 2011), especially in China, which has resulted in strict rules concerning the impact of products. The development of new urban markets in China has enhanced the domestic demands in furniture industries. The furniture market is increasing the awareness of their environmental pollution and energy consumption. Hence, environmental and economic concerns are stimulating research into green techniques, such Li et al. (2019). “Wardrobe case study in China,”

BioResources 14(2), 2740-2758.

2740

PEER-REVIEWED ARTICLE

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as selecting green materials, using renewable materials, and adopting cleaner processes and the eco-design approach (Luz et al. 2010). Composite boards for furniture in China are main panels, which are made from petroleum-based adhesives and have caused several negative environmental impacts, especially because of the emission of volatile organic compounds and formaldehyde during the production phase (Li et al. 2009).

As a by-product of the paper industry, industrial lignin has been used in a wide variety of fields in the past few years (Li et al. 2015; Ten and Vermerris 2015). Industrial lignin is used as a low-value fuel in paper-pulp manufacturing. In view of the recent focus of the community on sustainable development and carbon-neutral products, there have been several discussions and research on using lignin-based binders. Various kinds of lignin-based binders, such as industrial lignin alone or mixed with cross-linking agents, have been investigated in the last decade (Li and Geng 2004; Geng and Li 2006; Liu and Li 2006; Mancera et al. 2011; Duval et al. 2013; Privas and Navard 2013; Aracri et al.

2014; Zhang et al. 2017). However, industrial lignin has been found to be unsatisfactory as a binder in boards because of the relatively low reactivity of its chemical structure.

Therefore, the development of sustainable materials requires a more effective use of modified lignin (Ikeda et al. 2017). For instance, a major amount of research has investigated the manufacturing of nonconventional fiberboards by using a natural binder made with modified ammonium lignosulfonate (Yuan et al. 2014; Hu and Guo 2015).

Currently, the furniture manufacturing industry seems to be important from economic and social standpoints and from the perspective of environmentally compatible industries (Azizi et al. 2016). As an effective and valuable tool, the life cycle assessment (LCA) methodology is used to assess the environmental impact of materials, products, and service systems, with the intent of assessing the environmental damage caused over the whole life of a product (ISO 14040 2006). These trends reinforce the importance of using LCA for sustainable design procedures and for evaluating the novel material technologies and production processes that impact the environment in remarkable ways (Linkosalmi et al. 2016; Kirchain Jr. et al. 2017). Several studies have evaluated wood-based products and furniture from an LCA perspective. These studies have focused on conventional wooden material selection and assessment, such as standard particle boards, fiberboards, and hardboards (Iritani et al. 2015; Nakano et al. 2018). In contrast, only a few studies have applied LCA to furniture manufactured with nonconventional green boards. In China, no LCA studies have been performed to investigate the till date on furniture made with green wooden panels based on lignin-based binders.

The case study presented in this article focused on a complete wardrobe with new materials for the wardrobe components. A previous study used LCA to investigate a preliminary case on the comparative environmental performance of conventional mediumdensity fiberboard (MDF) and a nonconventional green board called hybrid modified ammonium lignosulfonate (HMAL)/wood fiber (WF) composite (HWC) (Yuan and Guo 2017). For HMAL, ammonium lignosulfonate was oxidized using H2O2 at 60 °C for 30 min, then mixed with PEI solutions according to the MAL/PEI weight ratio of 7:1.

To enhance the utilization of novel wood composites, sustainable strategies were analyzed by assessing the environmental impact of a wardrobe composed of HWC. This study evaluated the environmental impacts of using an HWC wardrobe. In the process, this study compared those impacts with the environmental impacts caused by current wood products made of conventional MDF over the entire life cycle of the wardrobe. The study intended to assess the effects of replacing the raw materials and current binder material

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with a modified lignosulfonate on the overall sustainable design of the HWC wardrobe and the important wood products sector in China.

EXPERIMENTAL Goal and Scope Definition The goal was to assess the environmental impacts (on human health, ecosystem quality, and resources) of a wardrobe made of HWC, and then compare them with the impacts caused by an MDF wardrobe made with conventional composite board with ureaformaldehyde adhesives. Other issues addressed were investigated and discussed in the discussion sections. This project was developed in partnership with a national company (the Greater Khingan Range Hengyou Furniture) located in Greater Khingan area, China.

This company that produces furniture was selected as a representative to provide related production inventory data required for this study. This company is one of the favorite Chinese producers of wooden furniture with an annual turnover of 3.82 million dollars in 2017.

Functional Unit The functional unit provides support for inputs and outputs based on ISO 14044 (2006). Wooden wardrobes are panel products commonly used indoors with a strong market demand. This study paid attention to wooden wardrobes with double doors used for primary needs because this is the most produced wardrobe in this specific factory. The functional unit that was selected corresponded to one wooden wardrobe (100 kg) with the main dimensions 2000 mm u 1000 mm u 500 mm (Fig. 1). The HWC for the main structure and material of the wardrobe was produced by the Chinese company mentioned above.

Metal, such as steel, was used in the screws, and plastics were used in the accessory members, packaging, etc.

500

20

80

1400

2000

1880

80

20

40

1000

10

485

10

485

10

500

Fig. 1. Schematic of wardrobe in function unit

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Description of the System The complete life cycle of manufacturing an HWC wardrobe from raw materials to production to delivery to the final user is illustrated in Fig. 2. The HWC wardrobe process chain was divided into the four following subsystems: raw materials supply, energy consumption, HWC wardrobe manufacturing, and transportation. The HWC wardrobe manufacturing stage was comprised of assembling, surface treatment, and packaging.

During assembling, the HWCs were cut, shaped into a given size, and connected with each other, and then surface treatments, such as painting, were performed. Packaging was the last production step before the wardrobe was delivered. Energy consumption, such as heating, electricity, and water consumption, was also considered in the assessment process.

All of the associated transportation processes in the life cycle, including waste disposal, were within the system boundaries. The use phase of furniture needed little energy input, and the maintenance data was out of reach; therefore, the use phase was excluded from the system boundary. Different scenarios of the end of life were considered during the sensitivity analysis.

RAW MATERIAL SUPPLY

Materials, Energy

HWC Paperboards

ENERGY CONSUMPTION HWC WARDROBE MANUFACTURING

Coating and Cutting

Metals Plastics

Emission to Air Emission to Solid Emission to Water

Drilling and Finishing

Adhesives and Glues Assembling and Packing Auxiliary Productions

100-kg HWC wardrobe Legend: Transport

Fig. 2. System boundary and main processes for production of HWC wardrobes

The raw materials supply stage included key materials (green chips and ammonium lignosulfonate) for the HWC, solid pine timber for paperboards, metals, plastics, and adhesives. Compared with conventional wardrobe, the main difference is the wooden composites. The green chips and ammonium lignosulfonate, as the primary materials of the HWC, were evaluated according to previous reports (Yuan and Guo 2017). The physical mechanical properties of HWC were superior to the furniture grade MDF of the Chinese standard GB/T 11718 (2009). The HWC was the primary integrating component of the wardrobe. The wardrobe was transported by truck from Hengyou Furniture Co. Ltd (Greater Khingan area, China) for an approximate distance of 200 km. The paperboards were used as a packaging material for one-layer corrugated boxes, which decreased the environmental impact and energy consumption by a large amount (Yi et al. 2017). Other components included metals, plastics, and adhesives, which were obtained from different suppliers in China. These components accounted for approximately 5.0% of the entire mass of the HWC wardrobe system.

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Data Quality and Simplification The LCA was built by GaBi 8.7 software (Thinkstep, Leinfelden-Echterdingen, Germany) for the HWC wardrobe system to investigate the inventory data and perform the impact assessment. The data quality was high and reliable; it came from different evaluation sources with reliability and consistency based on ISO standards. Additionally, data from secondary literature was used when the key process emission data was not available. To avoid irregular conditions, the representative process data consisted of the average data taken from the specific field methods.

The life cycle inventory for the HWC wardrobe is shown in Table 1. This study dealt with the lack of regional or local inventory databases. In these cases, valid assumptions and simplifications were made to integrate the available databases into the HWC wardrobe LCA. Therefore, it was important to consolidate the database inventories for reliable assessment and to introduce life cycle consciousness in the Chinese furniture industry (Teixeira et al. 2010).

Table 1. Life Cycle Inventory of 100-kg HWC Wardrobe Input

Amount

Output

Amount

Raw Materials

kg

Product

kg

Green Chips (50% water content)

202.55

HWC Wardrobe

100

Solid Pine Timber

11.34

Ammonium Lignosulfonate Hydrogen Peroxide (Aqueous 50 wt. %) Metals

23.73

Emission to Air

kg

14.92

Carbon Dioxide

16.19

19.71

Carbon Monoxide

0.07

Plastic

5.94

Nitrogen Oxides

0.49

polyvinyl Acetate Adhesive

0.63

Sulfur Dioxide

0.02

Polyurethane Coating

10.32

Emission to Soil

kg

Paraffin Emulsion

0.81

Dust Waste

41.05

Energy

MJ

Paints Waste

0.47

Electricity from Grid

392.5

Filterable Matter

0.47

Energy from Biomass

57.2

Emission to Water

kg

Transportation

ton·km

COD

0.11

Truck (4 ton to 5 ton)

16.93

Truck (12 ton to 14 ton)

25.47

All of the inventory data for the foreground of the wooden composites were from primary sources. Annual data for China were collected from furniture companies that used the modern furniture techniques. The environmental emission sources for HWC wardrobe manufacturing were coating, cutting, drilling, and finishing. The field emission data were estimated based on the Chinese standard HJ/T 315-2006 (2006) in the HWC wardrobe manufacturing subsystem. For material transportation, the transportation methods and distances were identified for each raw material according to procurement by the furniture manufacturers. The average distance between the sites of the country for product export and the main raw materials was taken from Chinese references (Chen et al. 2015).

Subsidiary processes included thermal energy consumption, electricity consumption, diesel Li et al. (2019). “Wardrobe case study in China,”

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consumption, and adhesive production, and were mainly obtained from GaBi Thinkstep databases (Thinkstep, 2018) and other databases to cover some missing datasets such as Ecoinvent 3.5 (Swiss Centre for Life Cycle Inventories, 2018). Lignosulfonate product specific LCA reports were also available, and the data sources are summarized in Table 2.

Table 2. Summary of Data Sources Category

Material/Component Green Chips (50% water content) Solid Pine Timber

Raw Materials

Ammonium Lignosulfonate

Lignin based phenolic material.

Hydrogen Peroxide (Aqueous 50 wt%)

RER: Hydrogen peroxide (50% H2O2)

Metals

GLO: Steel welded pipe worldsteel

Plastic Polyvinyl acetate adhesive Polyurethane coating Paraffin Emulsion Electricity from Grid Energy

Energy from Biomass Truck (4 ton to 5 ton)

Transportation

Data GLO: Used wood, wood chips (50% H2O content) CN: Timber pine (10.7% H2O content)

Truck (12 ton to 14 ton)

Fuel for transportation CN=China, GLO=Global, RER=Europe.

CN: Plastic foil (Polyethylene, PE) RER: Polyvinyl acetate (PVAC) RER: PUR dispersion adhesive CN: Wax / Paraffins at refinery from crude oil CN: Electricity from hard coal CN: Thermal energy from biomass (solid)

LCI Source Thinkstep GonzálezGarcía (2011) Ecoinvent 3.5 World Steel association (2017) Thinkstep Ecoinvent 3.5

Thinkstep

CN: Transport, small truck (up to 14 t total cap., 9.3t payload) CN: Diesel mix at filling station

Life Cycle Impact Assessment In this study, the ReCiPe 1.08 Endpoint method and its impact categories were selected for evaluating the different types of damages over the entire life of the product (La Rosa et al. 2013). The three main damage categories were damage to human health (HH), damage to the ecosystem quality (EQ), and damage to resources (R). Damage to HH was shown as the number of years lived as disabled and the number of years of life lost; its unit was disability adjusted life years (DALYs). Damage to the EQ was shown as the loss of species within a given period, and its unit was species years (species·yr). Damage to R was shown as the surplus of energy for future resource integration (Rivela et al. 2007).

This was helpful for highlighting the drawbacks of specific categories and the possible environmental benefits. When conventional MDF was replaced with HWC in the wardrobe products, it was essential to detect the hot spots and further demonstrate the observed impacts. The characterization step analyzed the contributions of different subsystems to the damage categories and sub-categories. The results of the characterization and damage assessment are shown in Tables 3 and 4.

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Table 3. Characterization and Damage Assessment of 100-kg HWC Wardrobe Characterization Step Category

Raw Material Supply

Unit

Energy Consumption

Wardrobe Manufacturing

Transportation

Total

Damage to Human Health Climate Change Human Health

DALY u E+3

72.12

51.8

3.71

33.7

161.33

Human Toxicity

DALY u E+3

52.89

7.75

6.25

58.10

124.99

Ionizing Radiation

DALY u E+7

47.91

34.42

2.47

22.40

107.20

Ozone Depletion

DALY u E+11

38.80

36.22

7.29

16.25

98.56

DALY u E+3

17.23

15.10

5.00

2.99

40.32

DALY u E+7

135.0

13.69

7.89

75.23

231.81

Particulate Matter Formation Photochemical Oxidant Formation

Damage to Ecosystem Quality Climate Change Ecosystems Freshwater Ecotoxicity Freshwater Eutrophication Marine Ecotoxicity Terrestrial Acidification Terrestrial Ecotoxicity

Species·yr u E+4

40.11

66.32

5.15

4.94

116.52

Species·yr u E+8

8.98

21.23

2.16

37.23

69.60

Species·yr u E+8

11.59

1.72

1.48

12.04

26.83

Species·yr u E+8

11.79

12.67

2.16

13.35

39.97

Species·yr u E+6

23.59

52.36

2.65

30.12

108.72

Species·yr u E+7

70.77

50.82

2.61

1.22

125.42

Damage to Resources Fossil Depletion

$ u E+3

64.53

53.70

1.83

32.49

152.55

Metal Depletion

$ u E+5

24.54

17.62

1.26

11.48

54.90

Damage Assessment DALY u E+2

HH EQ

Species·yr u

R

$u

E+4

E+3

14.23

7.47

1.49

9.49

32.68

40.40

66.44

5.18

49.74

161.76

64.78

53.88

1.843

32.61

153.11

Table 4. Life Cycle Impact Assessment of the Two Wardrobe Samples Under Study Category HH EQ R

Unit DALY u Species·yr u E+4 $ u E+3 E+2

Conventional Wardrobe 66.52 385.36 527.44

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HWC Wardrobe 32.68 161.76 153.11

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RESULTS AND DISCUSSION Main Findings Figure 3 shows the relative contributions of the four stages to each subsystem and the impact category. The contributions of the raw materials supply ranged from 25.0% for the EQ to 43.6% for HH, while the contribution of the energy consumption stage ranged from 21.3% for HH to 41.1% for the EQ. The transportation stage contributed 21.3% for R and 31.3% for the EQ, and the HWC wardrobe manufacturing stage contributed 1.2% for R to 3.8% for HH. It was found that the subsystems for the raw materials supply and energy consumption were responsible for all of the damage categories, and HWC wardrobe manufacturing had the lowest contribution to the environmental impact. This was consistent with the results of Yuan and Guo (2017).

Fig. 3. Relative contributions to the three main damage categories for the four stages of each subsystem

Fig. 4. Relative contributions to the sub-damage categories for the four stages of each subsystem

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Damage to Human Health Table 3 shows the relative contributions to the sub-damage categories for the four stages of each subsystem. Damage to HH was further divided into six sub-damage categories, which were climate change on HH (CCH), human toxicity (HT), particulate matter formation (PMF), ozone depletion (OD), ionizing radiation (IR), and photochemical oxidant formation (POF).

Considering the existing six categories (Fig. 4), 44.7% of the CCH damage occurred in the raw materials supply stage because of CO2 emissions from the production of HMAL/WF, and 32.1% of the CCH damage was because of energy consumption. For the HT category, 46.5% of the impact was caused during the energy consumption stage, and 42.3% of the environmental impact occurred during the raw materials supply stage.

For the PMF category, the impactful stages were the raw materials supply (42.7%) and energy consumption (37.5%). For the IR, OD, and POF categories, 44.7%, 32.1%, and 20.9% of the environmental impacts were caused during the raw materials supply stage, energy consumption stage, and transportation, respectively. For the OD category, 39.4% of the impact occurred in the raw materials supply stage and 36.7% of the impact happened during the energy consumption stage. The damage to HH was the main impact because the CCH, HT, and PMF categories had a total of 0.653 (Fig. 5). The sum of IR, OD, and POF was deemed the least important in the damage to HH.

Fig. 5. Differently weighted sub-damage categories

Damage to the Ecosystem Quality In Table 3, the damage to the EQ was further divided into six sub-damage categories, which were climate change ecosystems (CCE), freshwater ecotoxicity (FE), freshwater eutrophication (EP), marine ecotoxicity (ME), terrestrial acidification (AC), and terrestrial ecotoxicity (TE). The distribution stage was the main contributor, causing impacts of more than 44% for FE (53.5%), EP (44.9%), AC (48.9%), and TE (63.4%) for 2000-km distances (Fig. 4). This was because of diesel consumption in the transportation stage, which was due to fossil fuel consumption, as well as CO2 and CH4 emissions from fossil fuels. The CCE showed the highest impact with 0.0322, while the other sub-damage categories were less important with a sum of 0.000151 (Fig. 5).

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Especially for FE and EP, the HWC life cycle was contaminated by hydrophobic organic contaminants, e.g., polycyclic aromatic hydrocarbons, during field operations. The raw materials supply stage was the second largest contributor, causing impacts of more than 30%, such as for EP (43.2%) and AC (38.3%).

Damage to Resources The damage to R was divided into two sub-damage categories, which were fossil depletion (FD) and metal depletion (MD) (Table 3). Figure 5 shows that FD (0.305) had a higher impact than MD (0.001). The raw materials supply stage was the main contributor to MD (87.4%) and FD (42.4%). The energy consumption (35.2%) and transportation stages (21.3%) had the largest contributions to FD, as is shown in Fig. 5. Being a developing country, Chinese electric power comes from a mix of coal (77%), hydropower (18%), and other energy resources (5%) (Tong et al. 2013). Coal-based electricity generation plays an important role in national electricity production in China, which explained why electricity was the highest contributor in the damage to R (Hong et al. 2017).

Comparative Environmental Performance of the Wardrobe with the LCA Figure 6 shows the comparative environmental performance for the HWC and conventional wardrobes. These results showed that the HWC wardrobe provided superior environmental performance compared with the conventional wardrobe of the same size.

The results showed all of the inputs for the production process of the wardrobes, as well as the solid waste generation, energy consumption, and water consumption.

Fig. 6. Three main weighted damage categories for the conventional wardrobe and HWC wardrobe

Alternatives Focused on the Primary Component in the Wardrobe Life Cycle The raw materials supply stage presented a great opportunity for environmental improvement, followed by the energy consumption and transportation stages. The categories CCH, FD, HT, and PMF combined had the largest contribution to the overall environmental impact for the production system (Fig. 5). Other sub-damage categories had negligible contributions to the key categories. Figure 7 presents the relative contributions of the four main sub-damage categories for each subsystem.

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Main Sub-damage Categories Fig. 7. Relative contributions to the four main sub-damage categories for each subsystem

Climate change on human health The transportation stage was responsible for most of the CCH contribution (approximately 46%), as is shown in Fig. 7. The HWC and heating system contributed 25% and 7% to the impact, respectively. The combustion of fossil fuels to produce complete heat and electricity led to CO2 and CH4 emissions (approximately 16%).

Fossil depletion Transportation was responsible for most of the FD contribution (33%), followed by wood materials production (19%) and electricity (10%). The cogeneration unit, including metals, plastics, and adhesives, required in the packaging stage contributed approximately 23% to this impact category.

Human toxicity A high percentage of the total impact of the ecotoxicity potentials was linked to transportation activities (60%). The wood materials production was another hot spot with a contribution of 12% because of the wood fiber and auxiliary chemical materials required for HWC production.

Particulate matter formation The wood materials production had the largest contribution to this impact category (32%), and particulate matter was mainly emitted during HWC manufacturing (35%), followed by electricity production (25%) and heating (20%). The fiber preparation and board finishing of wood materials production are the main sector in the pollution of particulate matters (Kouchaki-Penchah et al. 2016). The fine particulate matter (PM10 and PM2.5) from the PMF category is related to respiratory problems in humans. Most of the major cities in China are afflicted by principal urban pollutants, which includes SO2 and NOx (Yao et al. 2009, 2010). Specifically, PM2.5, the pollutant with the highest amount in the region, adversely affects the Northern region of China (Song et al. 2016).

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Sensitivity Analysis Although the transportation stage was highlighted in the categories CCH, FD, and HT, the wood-based materials were the main contributor to the four impact categories. This was because HWC and solid wood represent 88% and 5% of the total weight, respectively.

Based on prior studies, it was found that HWC as the main wood-based material has better environmental performance properties. The main contributors to the environmental profile associated with HWC were the raw materials, energy, and chemicals required for production.

Particulate alternatives focused on wood-based materials In this study, wood-based materials were the main components of the wardrobe because HWC and solid pine timber represent 97% and 3% of the total weight, respectively. There is no published literature on strategies to replace HWC with alternative materials, especially using different kinds of recycled wood in the panel manufacturing process (Fig. 8). The four scenarios that are shown in Fig. 8 are outlined as follows: x Scenario 0: current model, using 100% raw wood (864 kg/cm3 HWC), x Scenario 1: conventional model, using 100% raw wood (864 kg/cm3 conventional MDF), x Scenario 2: using 50% virgin wood (432 kg/cm3 HWC) and 50% wood waste (432 kg/cm3 HWC), and x Scenario 3: using 0% virgin wood and 100% wood waste (864 kg/cm3 HWC).

Fig. 8. Scenario analysis: environmental impact for different doses of wood waste in wardrobe production

When comparing scenarios 0 and 1, the potential impact of conventional MDF was minimized by 6.9% for the evaluated categories. The largest increase in the impact that occurred was in the TE (21.0%), followed by the POF (18.1%). From the dominant categories above, the CCH, PMF, FD, and HT increased by 16.6%, 16.6%, 16.2%, and 13.3%, respectively. When comparing scenarios 0 and 2, there was an overall minimization of the potential impacts of more than 22.7%. The largest increase in the impacts occurred for the POF (42.1%), followed by the HT (42.0%). When comparing scenarios 0 and 3, there was an overall minimization of the potential impacts of more than 38.0% because this Li et al. (2019). “Wardrobe case study in China,�

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scenario proposed the use of 100% wood waste. Again, the greatest decrease in the potential impact occurred in the POF category (62.0%), followed by the HT (61.4%). In the case of the studied wood wardrobe, it was concluded that a more efficient use of wood waste as a raw material for the HWC in the wardrobe products can present environmental advantages by proposing a potential solution to overcome resource scarcity (Sommerhuber et al. 2017). For furniture manufacturing companies, a potential wood waste recyclingoriented business model could be developed (Daian and Ozarska 2009).

Alternatives focused on modified conditions of lignosulfonate The equivalence between the two HWC in terms of strength and stiffness has already been established, where two treatments were performed on lignosulfonate to improve the mechanical behaviors of the HWC for the technical project requirements.

Before HWC production, untreated lignosulfonate was purified and modified by Yuan et al. (2014) to increase the active groups in the lignosulfonate and improve the adhesion within the wood fibers. Various treatments have also been used by other researchers to improve the adhesion and analyze the effects of those treatments on the mechanical properties of the composites. However, these phases were not considered in the LCA. The four scenarios that are shown in Fig. 9 are outlined as follows: x Scenario 0: current model, HWC using purified and modified lignosulfonate, x Scenario 1: HWC using 20 wt.% unpurified lignosulfonate (based on AL consumption), x Scenario 2: HWC using 20 wt.% unmodified lignosulfonate (based on AL consumption), and x Scenario 3: HWC using 10 wt.% unpurified lignosulfonate and 10 wt.% unmodified lignosulfonate (based on AL consumption).

Fig. 9. Scenario analysis: weighted four main sub-damage categories

In this case study, lignosulfonate was used as a binder for the HWC. Different modified conditions of the lignosulfonate caused remarkable changes (Fig. 9). The results for scenario 2 showed that the HWC using 20 wt% unmodified lignosulfonate resulted in the largest influence on the main contributor, except for the PMF. However, when the dose of unpurified lignosulfonate was reduced, most of the impact categories became less Li et al. (2019). “Wardrobe case study in China,�

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relevant, with a difference of less than 2%, except for the CCH (5%). Overall, the results showed a minimum impact and demonstrated that the modified treatments possibly increased the impact of the HWC because of the inherent hazard of the intermediate benzene and phenol products (Eckelman 2016). This was an effort to adapt HMAL in green chemistry for industrial lignin.

Other alternative options in HWC wardrobe production The important contribution to the environmental feature of wardrobe production was the energy requirements from fossil fuels in a cogeneration system. This process showed an important role in terms of the CCH, FD, HT, and PMF because of the use of non-renewable fuel and its associated CO2 emissions (Vignali 2017). China is paying close attention to energy security, optimizing the energy structure, and reducing the emission factors of the grid mix (Myers 2016). For example, the application of solar, nuclear, and wind power can reduce the emission factor of electricity by 835 g CO2eq/kWh in China, which is higher than that in the USA (609 g CO2eq/kWh) (Qiao et al. 2017). Therefore, the energy efficiency and centralized transportation of HWC wardrobe production should be considered an important research target for furniture development to reduce the environmental impact of HWC wardrobe production (Peters et al. 2016).

Meanwhile, the transportation stage was relevant when relying on the distance optimized with consideration of improvement and management of integrated processes.

The reuse of waste production and energetic valorization are alternative options that promote cleaner production strategies. For the end of life stage, a landfill scenario was set for both the wardrobe scraps and wasted elbows because thermoset composites cannot be recycled and incineration with biological heat is not a valid option in China due to its low calorific value and high cost. In another scenario, the furniture companies could expand subsidies for consumers who are trading in an older wardrobe for sustainability in extended brand benefit. The refurbished wardrobe could be reused for a prolonged life cycle.

CONCLUSIONS 1. The hybrid modified ammonium lignosulfonate/wood fiber composites (HWC) wardrobe provided superior environmental performance compared with the conventional wardrobe of the same size. Concerning the composite materials, the wardrobe case study demonstrated that HWC presented a better solution to enhance the environmental performance of the complete wardrobe.

2. The hot spots that occurred over the life cycle of HWC wardrobe manufacturing process were identified from the inventory analysis and impact assessment results.

Three processes, namely the raw materials supply, energy requirements in cogeneration, and transportation activities, had a remarkable role in the environmental profile.

3. According to the four main sub-damage categories, the distribution stage was responsible for most of the climate change (CCH) contribution (approximately 46%).

For the fossil depletion (FD), transportation was responsible for most of the FD impact (33%). For the human toxicity (HT), a high percentage of the total impact of ecotoxicity potentials was linked to transportation activities (60%). For the particulate matter

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formation (PMF), the wood materials production was the largest contributor (32%), mainly from dust waste during HWC manufacturing (35%).

4. Alternative and potential scenarios were proposed and analyzed to compare their environmental profile with the current production process. An efficient use of wood waste as a raw material for the HWC in the wardrobe products can present environmental advantages. Different modified conditions of the lignosulfonate caused remarkable changes in environmental impact.

ACKNOWLEDGMENTS The authors are grateful for the support of the Special Fund for Forest Scientific Research in the Public Welfare (Grant No. 201504501-1); the National Natural Science Foundation of China (Grant No. 31801313); University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province (Grant No. UNPYSCT-2018085); Open Foundation of the Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region (Grant No. 201708); and the Doctor Initial Foundation of Heilongjiang Bayi Agricultural University (Grant No. XYB 2015-10).

APPENDIX List of Abbreviations AC Terrestrial acidification CCE Climate change ecosystems CCH Climate change on human health COD Chemical Oxygen Demand EP Freshwater eutrophication EQ Ecosystem quality FD Fossil depletion FE Freshwater ecotoxicity HH Human health HT Human toxicity HWC Hybrid modified ammonium lignosulfonate/wood fiber composites IR Ionizing radiation LCA Life cycle assessment LCI Life cycle inventory MD Metal depletion MDF Medium-density fibreboard ME Marine ecotoxicity OD Ozone depletion PMF Particulate matter formation POF Photochemical oxidant formation R Resources TE Terrestrial ecotoxicity

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DOI: 10.3390/polym9070261 Article submitted: November 9, 2018; Peer review completed: February 3, 2019; Revised version received: February 12, 2019; Accepted: February 13, 2019; Published: February 15, 2019.

DOI: 10.15376/biores.14.2.2740-2758

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PAPERmaking!

O THE PUBLISHERS U S S OF O PAPER TECHNOLOGY INTERNATIONAL FROM

Volume 6, Number 1, 2020

Cardboard-Based Packaging Materials as Renewable Thermal Insulation of Buildings: Thermal and Life-Cycle Performance M. Čekon, K. Struhala and R. Slávik.

Cardboard-based packaging components represent a material that has significant potential as a renewable source for exploitation in buildings. This study presents the results of thermal and environmental analyses of existing packaging materials compared with standard conventional thermal insulations.

Experimental measurements were performed to identify the thermal performance of studied cardboard packaging materials. Real-size samples were experimentally tested in laboratory measurements. The thermal resistance and conductivity of all the analyzed samples were measured according to the procedure indicated in the ISO8032 standard. A life-cycle assessment according to ISO 14040 was also performed to evaluate the environmental impacts related to the production of these materials. The results show that cardboard panels are a material with thermal and environmental properties on par with contemporary thermal insulations. Depending on their structure, the measured thermal conductivity varies from 0.05 to 0.12 –1 –1 W·m ·K and their environmental impacts are much lower than those of polyisocyanurate foam or mineral wool.

Contact information: Brno University of Technology, Faculty of Civil Engineering, Centre AdMaS, Antonínská 548/1, 601 90 Brnostřed, Czechia.

J. Renew. Mater. Supplement June 2017, 84-93.

DOI: 10.7569/JRM.2017.634135 CC BY-NC-ND - Creative Commons Attribution-NonCommercial-NoDerivs License. This license allows users to copy, distribute and transmit an article, adapt the article as long as the author is attributed, the article is not used for commercial purposes, and the work is not modified or adapted in any way.

The Paper Industry Technical Association (PITA) is an independent organisation which operates for the general benefit of its members – both individual and corporate – dedicated to promoting and improving the technical and scientific knowledge of those working in the UK pulp and paper industry. Formed in 1960, it serves the Industry, both manufacturers and suppliers, by providing a forum for members to meet and network; it organises visits, conferences and training seminars that cover all aspects of papermaking science. It also publishes the prestigious journal Paper Technology International and the PITA Annual Review, both sent free to members, and a range of other technical publications which include conference proceedings and the acclaimed Essential Guide to Aqueous Coating.

Page 1 of 11

Article 7 – Corrugated as Insulation

Cardboard-Based Packaging Materials as Renewable Thermal Insulation of Buildings: Thermal and Life-Cycle Performance M. Čekon*, K. Struhala and R. Slávik Brno University of Technology, Faculty of Civil Engineering, Centre AdMaS, Antonínská 548/1, 601 90 Brno-střed, Czechia Received November 14, 2016; Accepted February 23, 2017

ABSTRACT:

Cardboard-based packaging components represent a material that has significant potential as a renewable source for exploitation in buildings. This study presents the results of thermal and environmental analyses of existing packaging materials compared with standard conventional thermal insulations.

Experimental measurements were performed to identify the thermal performance of studied cardboard packaging materials. Real-size samples were experimentally tested in laboratory measurements. The thermal resistance and conductivity of all the analyzed samples were measured according to the procedure indicated in the ISO8032 standard. A life-cycle assessment according to ISO 14040 was also performed to evaluate the environmental impacts related to the production of these materials. The results show that cardboard panels are a material with thermal and environmental properties on par with contemporary thermal insulations.

Depending on their structure, the measured thermal conductivity varies from 0.05 to 0.12 W·m–1·K–1 and their environmental impacts are much lower than those of polyisocyanurate foam or mineral wool.

KEYWORDS: Cardboard, thermal insulation, thermal performance, environmental impacts, life-cycle assessment, packaging industry

1

INTRODUCTION

Currently, building energy efficiency is being emphasized in developed countries around the world as one of the ways for reducing climate change. One of the newest legal documents striving to support climate change mitigation is the recently ratified Paris Agreement [1], which demonstrates a global commitment to move towards a low carbon economy [2]. A key document in this regard in the European Union (EU) is Directive 2010/31/EU [3], which denotes that buildings in the EU should be built or renovated as near-zero energy buildings [4] with lowest possible environmental impacts after 2020 [5]. One of the simplest ways of complying with these requirements is by reducing heat loss through the building envelopes, which is synonymous with improving the thermal properties of the building envelopes. This can be achieved by adding a sufficient amount of thermal insulation. Many types of insulation materials are

*Corresponding author: cekon.m@fce.vutbr.cz DOI: 10.7569/JRM.2017.634135

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J. Renew. Mater. Supplement June 2017

currently available in the building sector [6]. Generally the public focus is on common thermal insulation systems that are often promoted by various subsidy programs, like Czech New Green Savings [7]. However, at the same time, the field of novel building materials with above average insulation properties is developing rapidly. In order to find new ways to optimize energy consumption and mitigate the environmental impacts of structural solutions and building materials, attention is being focused on the exploitation of recent interdisciplinary findings.

The starting point for the presented analysis was the fact that the contemporary packaging industry offers materials with interesting features: simplicity of production, thermal and acoustic properties and presumably also low environmental impacts related to the reuse of paper waste and recyclability of cardboard-based materials (CBMs). These features make corrugated fiberboard (CFB) or honeycomb fiberboard (HFB) an attractive alternative to commonly used thermal insulation materials. The potential use of CBMs in the construction industry has already been addressed in recently published works of several authors. This study follows the works of Asdrubali et al. described

CC BY-NC-ND - Creative Commons Attribution-NonCommercial-NoDerivs License This license allows users to copy, distribute and transmit an article, adapt the article as long as the author is attributed, the article is not used for commercial purposes, and the work is not modified or adapted in any way. © 2017 by M. Čekon, et al. This work is published and licensed by Scrivener Publishing LLC.

DOI: 10.7569/JRM.2017.634135

M.Čekon et al.: Cardboard-Based Packaging Materials as Renewable Thermal Insulation of Buildings

in [8] and [9], who evaluated the thermal, acoustic and environmental performance of single- and multilayer CFB and cellulose samples. Also related is the work of Secchi et al. [10], who investigated the acoustic and environmental performance of several cardboard- or cellulose-based acoustic panels. These three works show that CBMs are an interesting alternative to the common insulation materials. However, there is another approach regarding the evaluation of environmental impacts that has been implemented, which is detailed in this study.

The aim of this article is the evaluation of the thermal and environmental performance of selected CFB and HFB samples and their comparison with contemporary common insulation materials. Polyisocyanurate foam (PIR), expanded polystyrene (EPS) and mineral wool (MW) were selected as representatives of common contemporary insulation materials for the comparison.

2

EVALUATED MATERIALS

The main focus of this article lies in the evaluation of the thermal and environmental properties of the CBMs. This material is already well known in the packaging industry. Applications in the building industry also exist. CBM panels can be lightweight and structurally sound. They are commonly used for production of furniture, door wings or as a lightweight load-bearing substructure for decorative elements. Asdrubali et al.

[8] propose their use as acoustic insulation.

The CBMs exist in different forms. This article evaluates samples of the two most common forms. The first is called corrugated fiberboard (CFB) or pleated cardboard. It consists of a fluted corrugated sheet, which provides structural stiffness. This sheet can be covered with flat cardboard sheets on one or both sides. The CFB has been in use for a long time. It was patented in the 19th century [11]. The other evaluated form is honeycomb fiberboard (HFB). It uses a honeycomb structure with tubular or hexagonal shaped cells. Again, it can be covered with flat cardboard sheets. The sandwich structure with air cavities enclosed in the cardboard is essential for the CBMs thermal and acoustic properties. From an environmental point of view, the CBMs are interesting due to the possible use of secondary raw materials for their production. Recycling of CBMs is also rather simple. Such avoided depletion of primary raw materials should lead to a relatively low environmental profile of the material [10].

The analysis described in this article evaluates the thermal and environmental properties of seven CBM samples (M1 to M7) and compares them with PIR (sample M8), EPS (sample M9) and MW (sample M10).

All samples are shown in Figures 1 and 2.

J. Renew. Mater. Supplement June 2017

M1

M2

M3

M4

Figure 1 CFB and HFB samples M1 to M4 used in the thermal analysis.

M5

M6

M7

M8

M9

M10

Figure 2 CFB and HFB samples M5 and M6 used in the thermal analysis, HFB sample M7, and conventional thermal insulation samples M8 (PIR), M9 (EPS) and M10 (MW).

CC BY-NC-ND - Creative Commons

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DOI: 10.7569/JRM.2017.634135

Sample M1 is a HFB with hexagonal cells 68 mm high and 16 mm wide covered by flat cardboard sheet on both sides. Sample M2 is a combination of ten layers of CFB. Individual layers are 2 or 4 mm thick with alternating sequence: the orientation of CFBs rotates by 90° between layers. Sample M3 is a HFB with hexagonal cells 29 mm high and 14 mm wide covered by flat cardboard sheet on both sides. Sample M4 is made of two layers of HFBs with hexagonal cells 17 mm high and 14 mm wide covered by flat cardboard sheet on both sides. Sample M5 is a HFB with hexagonal cells 12.5 mm high and 13 mm wide covered by flat cardboard sheet on both sides. Sample M6 is a HFB with hexagonal cells 17 mm high and 14 mm wide covered by flat cardboard sheet on both sides. Sample M7 is a combination of 14 mm thick CFB panel placed perpendicular to two layers of 3 mm thick covering CFB. All evaluated CBM samples were obtained as waste products from the packaging industry.

The other three samples serve as a reference and are representative of the common contemporary thermal insulations. Sample M8 is made of PIR, which is a high performance thermal insulation in the building industry. Sample M9 is made of EPS and sample M10 is made of MW. Basic parameters of the samples are described in Table 1. Thermal parameters were determined by measurements which are described in Section 3.

The thermal conductivity of hydroscopic materials strongly depends on moisture. The moisture content of samples presented in Table 1 is so small that the samples are practically dry.

CBMs combine convection and radiation in closed air cavities. This thermal analysis is focused on measuring real thermal properties of the samples presented in Figures 1 and 2. These properties have been determined from measured heat flow under known boundary condition. Based on these measurements, the equivalent thermal resistance and thermal conductivity were determined.

Thermal resistance of tested samples was measured using guarded hot plate method in accordance with ISO 8302 [12]. A TLP 300 DTX-1 thermal conductivity measuring device from Taurus Instruments was used (Figure 3). This device can determine thermal resistance of samples with thickness from 20 mm to 80 mm. Maximum dimension of the measured samples is 300 mm × 300 mm and protected measured field represents an area of 100 mm × 100 mm. Upper and lower surfaces of the tested sample have a set temperature difference which is maintained to activate heat flow within the tested sample. Temperatures are controlled by Peltier elements. The total power of the elements is maintained to achieve one-dimensional steady-state heat transfer. Temperature difference on the sample’s surfaces is measured applying two batteries of thermocouples on each side. In terms of the equation (Eq. 1), the thermal resistance is calculated from heating power Q through measured area A and temperature difference between sample surfaces ΔT.

3

3.1 Thermal Measurement Procedure

THERMAL ANALYSIS

Common homogenous materials have thermal transfer mainly caused by thermal conduction. Tested

R=

ΔT × A [m2.K.W–1] Q

(1)

Although the TLP 300 DTX-1 device implements the system for estimating the thickness of the sample, the sample thickness could be distorted by applying the contact mat. Therefore, before testing each sample,

Table 1 Table of measured materials.

Sample Type

Thickness Bulk density Moisture ratio [mm] [kg·m–3] [kg·kg–1]

M1

HFB

69.662

24.50

2.60%

M2

CFB

34.007

89.52

2.82%

M3

HFB

30.400

37.35

3.98%

M4

HFB

26.810

47.93

3.48%

M5

HFB

13.268

48.25

1.43%

M6

HFB

18.130

38.72

1.69%

M7

CFB

28.625

129.02

3.89%

M8

PIR

20.084

52.33

n/a

M9

EPS

19.736

13.74

n/a

M10

MW

25.808

99.75

n/a

86

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Figure 3 The TLP 300 DTX-1 thermal conductivity measuring device.

CC BY-NC-ND - Creative Commons

M.Čekon et al.: Cardboard-Based Packaging Materials as Renewable Thermal Insulation of Buildings

its own measurements, weight and overall thickness have to be measured separately. The sample is placed between plates with upper and lower surface covered by contact mat with a thickness of 3 mm. The plastic foil with thermocouple batteries is installed between the contact mat and surface of sample. The higher plate is slowly lowered until the pressure on the sample reaches a predefined level. Considering 10 K temperature difference of both sample sides, testing may have several point measurements, which means various temperatures in the middle of the sample. The measurement process starts by cooling and/or warming plates at a predefined temperature in the measurement point. The top Peltier plate monitors voltage and electric current, whose values are used for determination of overall heating power. Finally, as demonstrated above, the thermal resistance of tested sample is calculated according to Equation 1. The time varying power is managed by microprocessor control system according to the surface temperatures of sample. It has mainly decreasing behavior until it reaches steady state corresponding to Fourier’s law. Measurement is completed if the time is over or stability criteria are reached. At the end the equivalent thermal conductivity coefficient λekv is calculated based on material thickness.

3.2

Thermal Measurement Results and Discussion

The testing of each sample included repeated measurements at different mean temperature levels: 10 °C, 20 °C and 30 °C respectively. The load force of 200 N was applied on the samples through the top plate during the measurements. The temperature dependency between thermal resistance and mean temperature of sample was recorded. Thermal resistance approximated by linear function indicates a similar tendency of the slope; the higher the temperature difference, the lower the thermal resistance of all tested samples.

Thermal conductivity of all materials described in Section 2 was measured. Thermal conductivity parameters at three different measurement points are presented in Figure 4.

The PIR has the lowest thermal conductivity. It is undoubtedly the best performing of all tested materials. Next, and relatively close to each other, are MW and EPS. Their thermal conductivity is approximately two times higher than the PIRs. The CBM samples reached various results. In general, it can be said that (logically) samples with more layers had better thermal conductivity. Supposedly the division of the air cavities eliminates the prevailing effect of convection. Samples with undivided air cavities reach worse results as the height of the

J. Renew. Mater. Supplement June 2017

Thermal conductivity [W/(m*K)]

DOI: 10.7569/JRM.2017.634135

0,16 0,14 0,12 0,10 0,08 0,06 0,04 0,02 0,00

M1

5

10 15 20 25 30 Mean temperature point measurement (°C)

M2

M3

M4

M5

M6

M7

M8

M9

35 M10

Figure 4 Thermal conductivity at mean temperature.

cavities increases. It is therefore logical to further develop materials with smaller and more numerous air cavities.

4

LIFE-CYCLE ASSESSMENT

An inseparable part of the research presented in this article is a life-cycle assessment (LCA) that evaluates and compares the environmental impacts of the individual materials. LCA is an analytical method for evaluation of the environmental impacts of products from the extraction of necessary raw materials for waste management. The method originated in the 1960s [13]. Currently the LCA framework is well established thanks to international standards like ISO 14040 [14].

This standard describes the general principles and gives the users a general framework for the evaluation. Specifics of the building industry have led to the creation of European standards, like EN 15804 [15] or EN 15978 [16], that address evaluation of building elements, materials or even whole buildings. Product category rules (PCR) [17] for Environmental Product Declarations are also considered in the presented evaluation. This PCR further specifies the evaluation methodology for thermal insulations; for example, it defines recommended boundary conditions and impact categories.

4.1 Goal and Scope of the LCA The goal of the presented LCA is to estimate the environmental impacts of the CBM samples and compare them with the environmental impacts of more common insulation materials. The application of the cardboard in building structures is not yet fully addressed.

Thus only the product stage defined in EN 15804 [15] is considered in the assessment. This approach is also known as cradle-to-gate LCA in the literature, e.g.

[18]. It means that only the environmental impacts

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M. Čekon et al.: Cardboard-Based Packaging Materials as Renewable Thermal Insulation of Buildings

related with the production of the assessed materials are included in the LCA; for example, extraction of raw materials, transport of the raw materials to the production facilities and the production process.

The results of individual materials should be compared on the basis of a “functional unit.” This reference unit should be common to all assessed samples. The functional unit for evaluation of the environmental impacts of thermal insulations is defined in the PCR as the mass (weight) of the insulation necessary to provide thermal resistance R = 1 m2·K·W–1 [17]. Asdrubali et al. [9] also used this approach in their work. This approach is suitable for comparison of homogenous thermal insulations with small air cavities like PIR, EPS, MW or foam glass. However, it is not suitable for the calculation of the environmental impacts of the described CBM samples. None of these samples has the thermal resistance R = 1 m2·K·W–1. It would be necessary to either stack several layers together or to increase the thickness of the samples. Either solution would distort the results. Stacking up several layers of the described CBMs is a simple solution for increasing the thermal resistance. However, the thermal resistance of the stacked CBM layers would still not be equal to 1 m2·K·W–1. Increasing the thickness of one layer would increase the thermal resistance as well as mass, but the increase will not be linear. The thermal resistance of the described CBM samples is related to their shape, especially to the dimensions of the air cavities. Increasing the thickness would reduce the ratio between the samples’ thermal resistance and mass. Therefore, we decided to use mass of 1 m2 of a cardboard sample as a functional unit in this work.

Secchi et al. used a similar approach [10]. However, they did not sufficiently address the fact that individual samples have different physical properties.

According to the measurements presented in the previous sections, each CBM sample has different mass and thermal resistance. Therefore, direct comparison of the environmental impacts of the samples is impossible with the specified functional unit. Still, each CBM sample can be separately compared with the mass of the PIR, EPS and MW necessary to reach the same thermal resistance at 20 °C (see Table 2). The results of such partial LCAs should still be sufficient to indirectly identify the most environmentally friendly CBM sample.

4.2

Life-Cycle Inventory and Impact Assessment

Individual materials are represented by generic data from ecoinvent 2.0 database [19] in this LCA. These generic data describe production of PIR, EPS and MW from primary raw materials. It should be noted that

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Table 2 Thermal resistance at mean temperature.

Equivalent thermal resistance at specific mean temperature [m2·K·W–1] Thickness [mm]

10 °C

20 °C

30 °C

M1

69.662

0.5969

0.5195

0.4544

M2

34.007

0.6997

0.6870

0.6309

M3

30.400

0.3382

0.3177

0.2892

M4

26.810

0.3688

0.3505

0.3246

M5

13.268

0.1879

0.1781

0.1646

M6

18.130

0.2345

0.2222

0.2056

M7

28.625

0.4587

0.4438

0.4222

M8

20.084

1.0856

1.0571

0.9943

M9

19.736

0.5194

0.5048

0.4837

M10

25.808

0.6938

0.6738

0.6452

Sample

Table 3 Thermal resistance at mean temperature.

Equivalent thermal conductivity coefficient at specific mean temperature [W·m·1·K·–1] Thickness [mm]

10 °C

20 °C

30 °C

M1

69.662

0.1167

0.1341

0.1533

M2

34.007

0.0486

0.0495

0.0539

M3

30.400

0.0899

0.0957

0.1051

M4

26.810

0.0727

0.0765

0.0826

M5

13.268

0.0706

0.0745

0.0806

M6

18.130

0.0773

0.0816

0.0882

M7

28.625

0.0624

0.0645

0.0678

M8

20.084

0.0185

0.0190

0.0202

Sample

M9

19.736

0.0380

0.0391

0.0408

M10

25.808

0.0372

0.0383

0.0400

the description of the cardboard in the used dataset mentions the use of recycled secondary raw materials, but with no specifications. The assessment itself is conducted by a GaBi software tool.

The assessed mass of the materials considered in the LCAs is specified in Table 4. It is calculated based on the samples’ densities specified in Table 1 and thermal resistances at 20 °C specified in Table 2. The first column in the table specifies mass of the CBM samples according to data from the aforementioned tables. The other columns in each row specify the equivalent mass of the PIR, EPS and MW necessary to provide the same thermal resistance as the CBMs in the first column.

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M.Čekon et al.: Cardboard-Based Packaging Materials as Renewable Thermal Insulation of Buildings

Table 4 Mass of the insulation materials used as a basis

for the LCAs. Equivalent mass of common insulation materials [kg] CBM sample Mass [kg] PIR (M8) EPS (M9) MW (M10) M1

1.7067

1.4308

0.1826

1.3530

M2

3.0443

1.8921

0.2414

1.7892

M3

1.1354

0.8750

0.1116

0.8274

M4

1.2850

0.9654

0.1232

0.9129

M5

0.6402

0.4905

0.0626

0.4639

M6

0.7020

0.6120

0.0781

0.5787

M7

3.6932

1.2223

0.1560

1.1558

It is obvious that the EPS is the material with the best ratio between thermal insulation and mass in the presented comparison. The mass of the EPS necessary to provide the same thermal resistance as the CBMs varies between 4% (compared with CBM sample M7) and 11% (compared with CBM sample M1) of the CBMs mass. The necessary mass of PIR and MW is significantly larger, with MW being slightly more efficient in this regard. The mass of PIR varies between 35% (compared with CBM sample M7) and 87% (compared with CBM sample M6) of the CBMs mass. The mass of MW between 35% (compared with CBM sample M7) and 82% (compared with CBM sample M6).

The resulting environmental impacts are calculated using CML 2001 method developed by the Institute of Environmental Sciences in Leiden, Netherlands [20], with impact categories and characterization factors in version Nov 10. This method uses 12 “impact categories” to describe the environmental impacts of products. Only seven impact categories mandatory according to EN 15804 [15] and EN 15978 [16] standards are used in the LCAs presented in the following section: Abiotic Depletion Potential with regard to fossil fuels (ADP-fos.) and scarce resources (ADP-el.), Acidification Potential (AP), Eutrophication Potential (EP), Global Warming Potential (GWP), Ozone Depletion Potential (ODP) and Photochemical Ozone Creation Potential (POCP). Results in each impact category are represented by “equivalent units.” These units express the harm that the assessed product system causes to the environment by comparing it to damage caused by defined reference substance. For example, in GWP impact category the environmental impacts of the assessed product system are expressed by the amount of CO2 emissions that would cause the same damage if released into the atmosphere [18].

Results in individual impact categories can be confusing for the general reader. Also, individual categories

J. Renew. Mater. Supplement June 2017

have different equivalent units. This makes direct evaluation and comparison between them impossible.

A method known as “normalization” can be used to overcome this problem and increase the clarity of the results [18]. Normalization transforms the results in individual impact categories into dimensionless quantities that can be easily compared either separately or as a sum. It is, for example, used to compare the share of individual impact categories on total results.

CML2001 EU25+3 normalization factors in version Nov 10 are used in this work.

4.3

LCA Results

Table 5 shows calculated environmental impacts related to production of 1 kg of each assessed material: CBMs (representing samples M1 to M7), PIR (sample M8), EPS (sample M9) and MW (sample M10). Table 6 shows normalized environmental impacts related to the production of 1 kg of these materials.

Figures 5 to 11 present the comparison of normalized environmental impacts (vertical axis) related to the production of each CBM as well as the environmental impacts related to the production of comparable mass of PIR, EPS or MW. Share of the

Table 5 Environmental impacts related to the production of 1 kg of the assessed materials.

Impact cat.

Unit –6

CBM

PIR

EPS

MW

ADP-el.

10 kg Sb-Eq.

1.7

22.6

0.6

3.6

ADP-fos.

10–2 MJ

1.5

6.5

6.8

2.6

AP

10–3 kg SO2-Eq.

2.9

17.8

15.0

8.4

–3

EP

10 kg Phs-Eq.

1.1

3.1

1.4

1.1

GWP

10–1 kg CO2-Eq.

7.8

43.1

42.0

14.6

ODP

10–8 kg R11-Eq.

9.8

2.0

13.1

6.5

3.9

35.7

89.9

7.3

POCP

–4

10 kg eth-Eq.

Table 6 Normalized environmental impacts related to

the production of 1 kg of the assessed materials.

Impact cat.

Unit

CBM

PIR

ADP-el.

10

–13

EPS

MW

2.9

ADP-fos.

10–16

4.3

37.5

1.0

6.0

18.7

19.3

AP

10

–13

7.4

EP

10–14

1.7

10.6

8.9

5.0

5.8

16.5

7.5

GWP

5.7

10–13

1.5

8.3

8.1

2.8

ODP

10

–15

9.7

2.0

12.8

6.3

POCP

10–13

2.2

20.6

52.0

4.2

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89

MW

EPS

PIR

M1

0.0E + 00

ODP

1.2E – 11 GWP

8.0E – 12

EP

6.0E – 12 AP

4.0E – 12 2.0E – 12

ADP fos.

MW

EPS

PIR

M2

0.0E + 00

Total normalized env. impacts (–)

7.0E – 12

ODP

6.0E – 12 5.0E – 12

GWP

4.0E – 12

EP

3.0E – 12 AP

2.0E – 12 1.0E – 12

ADP fos.

MW

EPS

PIR

M3

0.0E + 00

ADP el.

Figure 7 Total normalized environmental impacts related to production of CBM M3 and equivalent mass of PIR, EPS and MW.

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J. Renew. Mater. Supplement June 2017

3.0E – 12

GWP

2.5E – 12 EP

2.0E – 12 1.5E – 12

AP

1.0E – 12 5.0E – 13

ADP fos.

ADP el.

Figure 9 Total normalized environmental impacts related to production of CBM M5 and equivalent mass of PIR, EPS and MW.

POCP

8.0E – 12

ODP

3.5E – 12

0.0E + 00

ADP el.

Figure 6 Total normalized environmental impacts related to production of CBM M2 and equivalent mass of PIR, EPS and MW.

4.0E – 12

M5

1.0E – 11

POCP

4.5E – 12 Total normalized env. impacts (–)

Total normalized env. impacts (–)

1.4E – 11

ADP el.

Figure 8 Total normalized environmental impacts related to production of CBM M4 and equivalent mass of PIR, EPS and MW.

POCP

1.6E – 11

ADP fos.

0.0E + 00

ADP el.

Figure 5 Total normalized environmental impacts related to production of CBM M1 and equivalent mass of PIR, EPS and MW.

1.0E – 12 MW

ADP fos.

MW

2.0E – 12

AP

2.0E – 12

6.0E – 12

POCP

5.0E – 12

ODP

4.0E – 12

GWP

3.0E – 12

EP

2.0E – 12

AP

1.0E – 12 0.0E + 00

ADP fos.

MW

AP

EP

3.0E – 12

M4

4.0E – 12

4.0E – 12

EPS

EP

GWP

EPS

6.0E – 12

5.0E – 12

EPS

GWP

ODP

6.0E – 12

PIR

8.0E – 12

7.0E – 12

PIR

ODP

POCP

PIR

1.0E – 11

DOI: 10.7569/JRM.2017.634135

8.0E – 12

M6

POCP Total normalized env. impacts (–)

1.2E – 11

Total normalized env. impacts (–)

Total normalized env. impacts (–)

M. Čekon et al.: Cardboard-Based Packaging Materials as Renewable Thermal Insulation of Buildings

ADP el.

Figure 10 Total normalized environmental impacts related to production of CBM M6 and equivalent mass of PIR, EPS and MW.

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M.Čekon et al.: Cardboard-Based Packaging Materials as Renewable Thermal Insulation of Buildings

1.2E – 11

POCP

1.0E – 11

ODP

8.0E – 12

GWP

6.0E – 12

EP

4.0E – 12

AP

2.0E – 12

MW

EPS

PIR

0.0E + 00

ADP fos.

M7

Total normalized env. impacts (–)

DOI: 10.7569/JRM.2017.634135

ADP el.

Figure 11 Total normalized environmental impacts related to production of cardboard M7 and equivalent mass of PIR, EPS and MW.

individual impact categories on the normalized environmental impacts is highlighted by different colors. We can see that the consumption of natural resources represented by ADP-el. (excluding fossil fuels) has the highest share of the results in the case of PIR (48%), MW (32%) and CBMs (32%). The only exception is EPS (13%), which is probably due to its very low density and thus low consumption of raw materials. The second most important category in regard to its share on total results is the POCP. It has a 73% share on normalized environmental impacts of EPS and 26% to 22% share on environmental impacts of PIR, MW and CBMs. The environmental impacts in these two categories alone represent 75% (EPS), 74% (PIR), 57% (CBMs) and 55% (MW) of total normalized environmental impacts of the assessed materials.

4.4

LCA Discussion

The results of individual LCAs in Figures 5 to 11 show that environmental impacts related to the production of the CBMs are comparable with environmental impacts of other common insulation materials.

The worst environmental impacts in all seven LCAs are related to PIR insulation. It has environmental impacts that are three (compared with M7) to eight (compared with M6) times higher than the tested CBMs. This is due to the very demanding production process of the PIR (see the normalized environmental impacts related to ADP-el.). This category represents the consumption of resources (excluding fuels). Environmental impacts related to the production of PIR in this category alone are higher than the

J. Renew. Mater. Supplement June 2017

total normalized environmental impacts of any other assessed material.

The environmental impacts of MW are worse than CBMs M1 to M6. Only the environmental impacts of sample M7 are 54% higher than those of MW. The reason why MW has higher environmental impacts than six out of seven tested CBMs lies in the combination of its relatively high density and environmental impacts per 1 kg. Table 4 and the accompanying text in Section 4.2 have already explained the small difference between the compared mass of MW and CBMs. This is combined with the fact that environmental impacts of the production of MW are twice as high as environmental impacts of the production of CBM (see Tables 5 and 6). The resulting comparison is a fine example of the necessity of complex multi-criteria evaluations: it proves that even if a material has worse physical properties, it can still be potentially better than others overall.

EPS has lower environmental impacts than any assessed CBM. The difference varies between 12% (in the case of HFB M6) and 63% (in the case of CFB M7). CBMs have lower environmental impacts per 1 kg than EPS (see Tables 5 or 6). However, the EPS has higher thermal resistance and lower density than any assessed CBM sample. Therefore, the compared masses of EPS and CBMs differ greatly, which favors the EPS overall.

The obtained results correspond with the findings of Asdrubali et al. [9]. The results of their LCA also show that the CBMs have environmental impacts similar to EPS and MW.

5

CONCLUSION

This paper introduces a potential novel thermal insulation material for buildings—CBM. In general, the results show that when compared by thickness the thermal properties of the CBMs are almost two times worse than those of more common insulation materials. Depending on their internal structure, the measured thermal conductivity varies from 0.05 to 0.12 W·m–1·K–1. This basically corresponds to the results achieved by Asdrubali et al. [8], who measured the thermal conductivity of cardboard-based panels to be around 0.055 W·m–1·K–1. However, there is further potential for improvement. The results show that thermal properties of CBMs are directly dependent on the size and shape of air cavities enclosed in the CBMs’ structure. Modifications of these air cavities could improve the thermal properties of CBM to levels comparable with common thermal insulation materials.

Based on this study we can say that CFBs appear to

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M. Čekon et al.: Cardboard-Based Packaging Materials as Renewable Thermal Insulation of Buildings

have the best thermal performance. In particular, sample M2 combining multiple layers of CFB has thermal parameters comparable with contemporary common thermal insulations.

The presented LCAs show that from an environmental point of view the CBMs are an interesting option comparable with other contemporary thermal insulations. Based on the results we can conclude that CBMs have significantly better environmental impacts than PIR. Most of the tested samples also achieved lower environmental impacts than MW, although the differences are lower compared to PIR: between −38% (sample M3) and +67% (sample M7). On the other hand, we have to highlight the fact that none of the tested CBMs have lower environmental impacts than EPS. The difference is between 12% (sample M6) and 67% (sample M7).

Further research and development in the field of CBM insulations should focus on multilayer sandwich structures with smaller air cavities. These proved to have the best thermal properties. However, the increased number of layers should not cause a significant increase of environmental impacts. The use of recycling and secondary raw materials should be promoted as most of the environmental impacts are related to the consumption of natural resources. Case studies created in cooperation with producers of CBMs are necessary. Such case studies will improve the accuracy of existing results. The case studies should also address the topic of additives that can improve the properties of the CBMs: fire resistance, water resistance, durability and load-bearing capacity. A cost analysis is also necessary to address the question of return on possible investments. Equilibrium between improving the properties of the CBM, its environmental qualities and costs should be the final aim of all further works.

ACKNOWLEDGMENT This research was supported by the project GA 16-02430Y “Contemporary concepts of climatically active solar façades integrating advanced material solutions,” supported by the Czech Science Foundation and under project No. LO1408 “AdMaS UP – advanced materials, structures and technologies,” supported by the Ministry of Education, Youth and Sports under the National Sustainability Programme I.

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2. F. Kern and K.S. Rogge, The pace of governed energy transitions: Agency, international dynamics and the global Paris agreement accelerating decarbonisation processes? Energy Res. Soc. Sci. 22, 13–17 (2016).

3. Directive 2010/31/EU of the European Parliament and of the Council of 19 May 2010 on the energy performance of buildings (EPBD). OJEU 153, 13–35 (2010).

4. C. Despret, M. Economidou, N. Griffiths, J. Maio, I. Nolte, and O. Rapf, Principles for Nearly Zero-Energy Buildings, pp. 5, Buildings Performance Institute Europe, Brussels (2011).

5. C. Beschio, P. Dabbene, E. Fabrizio, V. Monetti, and M. Filippi, Cost optimality assessment of a single family house: Building and technical systems solutions for the nZEB target. Energy Build. 90, 173–187 (2015).

6. B.P. Jelle, Traditional, state-of-the-art and future thermal building insulation materials and solutions – Properties, requirements and possibilities. Energy Build.

43, 2549–2563 (2011).

7. State Environmental Fund of the Czech Republic (SEFCR), New Green Savings Programme, http:// www.novazelenausporam.cz/en/ (2016).

8. F. Asdrubali, A.L. Pisello, F. D’Alessandro, F. Bianchi, M. Cornicchia, and C. Fabiani, Innovative cardboard based panels with recycled materials from the packaging industry: Thermal and acoustic performance analysis. Energy Procedia 78, 321–326 (2015).

9. F. Asdrubali, A.L. Pisello, F. D’Alessandro, F. Bianchi, C. Fabiani, M. Cornicchia, and A. Rotili, Experimental and numerical characterization of innovative cardboard based panels: Thermal and acoustic performance analysis and life cycle assessment. Build. Environ. 95, 145–159 (2016).

10. S. Secchi, F. Asdrubali, G. Cellai, E. Nannipieri, A. Rotili, and I. Vannucchi, Experimental and environmental analysis of new sound-absorbing and insulating elements in recycled cardboard. J. Build. Eng. 5, 1–12 (2016).

11. A.L. Jones, Improvement in paper for packing, US Patent 122023 (1871).

12. Thermal insulation – Determination of steady-state thermal resistance and related properties – Guarded hot plate apparatus, ISO 8302 (1991).

13. R.G. Hunt, W.E. Franklin, and R.G. Hunt, LCA – How it came about – Personal reflections on the origin and the development of LCA in the USA. Int. J. Life Cycle Assess.

1, 4–7 (1996).

14. Environmental management – Life cycle assessment – Principles and framework, ISO 14040 (2006).

15. Sustainability of construction works – Environmental product declarations – Core rules for the product category of construction products, EN 15804 (2012).

16. Sustainability of construction works – Assessment of environmental performance of buildings – Calculation method, EN 15978 (2011).

17. S. Rossi, Product Category Rules according to ISO 14025:2006, Product group: Multiple UN CPC codes, Insulation materials, pp. 5, Life Cycle Engineering srl, Torino (2014).

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18. H. Baumann and A.-M. Tillman, The Hitch Hiker’s Guide to LCA: An Orientation in Life Cycle Assessment Methodology and Application, Professional Public Service, USA (2004).

19. R. Frischknecht, N. Jungbluth, H.-J. Althaus, G. Doka, R. Dones, T. Heck, S. Hellweg, R. Hischier, T. Nemecek, G. Rebitzer, M. Spielmann, and G. Wernet, Overview and Methodology. Final report ecoinvent data v2.0, No. 1.

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Swiss Centre for Life Cycle Inventories, Switzerland (2007).

20. M. Z. Hauschild, M. Goedkoop, J.Guinée, R. Heijungs, M. Huijbregts, O. Jolliet, M. Margni, A. De Schryver, S. Humbert, A. Laurent, S. Sala, and R. Pant, Identifying best existing practice for characterization modelling in life cycle impact assessment. Int. J. Life Cycle Assess. 18, 683–697 (2013).

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PAPERmaking!

O THE PUBLISHERS U S S OF O PAPER TECHNOLOGY INTERNATIONAL FROM

Volume 6, Number 1, 2020

Removal of pharmaceuticals from municipal wastewater by adsorption onto pyrolyzed pulp mill sludge a

b

b

b

a

R.N. Coimbra , V. Calisto , C.I.A. Ferreira , V.I. Esteves , M. Otero .

A charcoal was produced from primary pulp mill sludge and then used for the adsorptive removal of diclofenac, salicylic acid, ibuprofen and acetaminophen. A main aim was to assess the utilization of this material for the tertiary treatment of sewage. For this purpose, the adsorption of the selected pharmaceuticals from the secondary effluent of a sewage treatment plant (STP) was compared with their adsorption from ultrapure water. Differences in the adsorption kinetics and equilibrium were evident between the four pharmaceuticals considered. However, differences between the adsorption from the two aqueous matrixes considered were negligible. It was hypothesized that synergetic microorganism removal compensated the competitive effects in wastewater.

Contact information: a Department of Applied Chemistry and Physics, Institute of Environment, Natural Resources and Biodiversity (IMARENABIO), University of Leo´n, Leo´n 24071, Spain b Department of Chemistry and CESAM (Centre for Environmental and Marine Studies), University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal Arabian Journal of Chemistry (2019) 12, 3611–3620 http://dx.doi.org/10.1016/j.arabjc.2015.12.001 This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

The Paper Industry Technical Association (PITA) is an independent organisation which operates for the general benefit of its members – both individual and corporate – dedicated to promoting and improving the technical and scientific knowledge of those working in the UK pulp and paper industry. Formed in 1960, it serves the Industry, both manufacturers and suppliers, by providing a forum for members to meet and network; it organises visits, conferences and training seminars that cover all aspects of papermaking science. It also publishes the prestigious journal Paper Technology International and the PITA Annual Review, both sent free to members, and a range of other technical publications which include conference proceedings and the acclaimed Essential Guide to Aqueous Coating.

Page 1 of 11

Article 8 – Novel Use of Paper Sludge Ash

Arabian Journal of Chemistry (2019) 12, 3611–3620

King Saud University

Arabian Journal of Chemistry www.ksu.edu.sa www.sciencedirect.com

ORIGINAL ARTICLE

Removal of pharmaceuticals from municipal wastewater by adsorption onto pyrolyzed pulp mill sludge R.N. Coimbra a, V. Calisto b, C.I.A. Ferreira b, V.I. Esteves b, M. Otero a,* a Department of Applied Chemistry and Physics, Institute of Environment, Natural Resources and Biodiversity (IMARENABIO), University of León, León 24071, Spain b Department of Chemistry and CESAM (Centre for Environmental and Marine Studies), University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal

Received 22 August 2015; accepted 1 December 2015 Available online 11 December 2015

KEYWORDS Paper sludge; Pyrolysis; Wastewater treatment; Emerging contaminants; Pain reliever; Sorption

Abstract A charcoal was produced from primary pulp mill sludge and then used for the adsorptive removal of diclofenac, salicylic acid, ibuprofen and acetaminophen. A main aim was to assess the utilization of this material for the tertiary treatment of sewage. For this purpose, the adsorption of the selected pharmaceuticals from the secondary effluent of a sewage treatment plant (STP) was compared with their adsorption from ultrapure water. Differences in the adsorption kinetics and equilibrium were evident between the four pharmaceuticals considered. However, differences between the adsorption from the two aqueous matrixes considered were negligible. It was hypothesized that synergetic microorganism removal compensated the competitive effects in wastewater. Ó 2015 The Authors. Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

1. Introduction The pulp and paper industry is a strategic economic sector in Europe that largely contributes to the European Union (EU) financial growth and job creation (CEPI, 2013). However, a main counterpart is that pulp and paper production processes are very demanding in terms of energy and water and this industry is considered one of the most polluting in the world (Ince et al., 2011). As a consequence of the high * Corresponding author.

E-mail address: marta.otero@unileon.es (M. Otero).

Peer review under responsibility of King Saud University.

Production and hosting by Elsevier

water consumption, large wastewater volumes are generated by the pulp and paper industry. This wastewater must be treated before discharge in order to accomplish with environmental regulations (Pokhrel and Viraraghavan, 2004). Therefore sludge from wastewater treatment is an unavoidable waste for the pulp and paper industry.

Elliott and Mahmood (2005) estimated that around 50 kg of dry sludge result from the production of a tonne of paper, of which approximately 70% is primary sludge and 30% is secondary sludge.

Thermal valorization may be considered a viable management choice for such wastes given that landfilling has been prohibited at the EU and that alternatives such as agriculture application or composting are not viable due to the composition of sludge from the pulp and paper industry (Méndez et al., 2009).

Among thermal valorization options for the pulp and paper wastes it is pyrolysis, also called destructive distillation (Monte et al., 2009). It involves the heating of the organic waste in the absence of oxygen

http://dx.doi.org/10.1016/j.arabjc.2015.12.001 1878-5352 Ó 2015 The Authors. Published by Elsevier B.V. on behalf of King Saud University.

This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

3612 yielding a mixture of gaseous and liquid fuels, with a solid inert residue (char). Yang et al. (2013) reported that gas, liquid (bio-oil) and char and gas yields were 11, 10 (27.9 daf, wt%) and 79 wt%, respectively, and that the bio-oil, with a higher heating value (HHV) of 36.5 MJ kg 1 and low oxygen content, supplied heat enough to power a diesel engine. Then, Ridout et al. (2015) proved that the bio-oil yield could be increased by fast pyrolysis. However, in practice, pyrolysis is not a preferred management option for paper industry wastes (Monte et al., 2009). Adding some value to the solid residue (char) from pyrolysis would undoubtedly boost this waste-to-energy management choice. The practical utilization of char as adsorbent for wastewater treatment is a way to do it. In this sense, chars from different paper waste materials have been used to adsorb trace metals (Méndez et al., 2009) and pharmaceuticals (Calisto et al., 2014) from water.

Traditionally, pharmaceuticals were not considered as environmental pollutants, but at present they constitute a group of great concern among emerging contaminants (ECs). Pharmaceuticals were designed to cause a physiological response and their presence in the environment may affect non-target individuals and species, which has raised alarms for possible impacts on human health (Santos et al., 2010).

The way that ECs enter the environment depends on their pattern of usage and mode of application but, in the case of pharmaceuticals coming from human use and/or excretion, municipal sewage treatment plants (STPs) are important sources in the aquatic environment (Farré et al., 2008). Actually, STPs were conceived to reduce the concentration of legislated parameters, such as chemical oxygen demand (COD), biological oxygen demand (BOD), total suspended solids (TST) and nutrients but not emerging contaminants (ECs), such as pharmaceuticals. However, it is expected that in the nearer future more strict legislation will come out on the discharge of pharmaceuticals. In fact, pharmaceuticals have been included in the first observation list of the Water Framework Directive (WFD). Removal of these pollutants at STPs could be attained by the inclusion of a tertiary treatment before discharge. Among the several treatment options, adsorptive processes have been pointed to have large potential for the removal of ECs from water as they do not imply the generation of transformation products (Bolong et al., 2009; Priac et al., 2014). Furthermore, adsorptive treatments are advantageous from a practical point of view, due to their convenience incorporation into current water treatment processes (Domı́nguez et al., 2011).

In this context, research on the adsorptive removal of ECs and, namely, pharmaceuticals from water has largely increased in the last years. However, most of the published works report the adsorption of this sort of pollutants onto different adsorbents from distilled or ultrapure water but not from real wastewater. However, a main issue for the applicability of any adsorbent in tertiary treatment is the study of its utilization for pharmaceuticals adsorption from real wastewater.

Therefore, this work aimed to assess the utilization of pyrolyzed paper mill sludge for the removal of pharmaceuticals from wastewater by comparing their adsorption from the secondary effluent of a STP with their adsorption from ultrapure water. For this purpose, the selected pharmaceuticals were pain relievers, namely diclofenac, ibuprofen, salicylic acid and acetaminophen. These pharmaceuticals belong to the anti-inflammatory and/or analgesic groups and among the most commonly used of all medications in the world and, consequently, also among the most frequently found drugs in STP effluents and natural waters.

2. Materials and methods 2.1. Adsorbent materials Primary sludge (PS) was collected from a mill that employs the kraft elemental chlorine free (ECF) pulp production process, which operates exclusively with eucalyptus wood (Eucalyptus globulus). PS, which is produced at an average rate of 20 kg

R.N. Coimbra et al. per ton of air-dried pulp, results from fibers rejected after the cooking/digestion pulping step and losses of fibers and other solids which occur when liquid effluents are involved (for example, washing and bleaching). After collection, PS was dried at room temperature and then subjected to oven drying at 60 °C, blade milled and pyrolyzed in a Nüve muffle (MF 106, Turkey). The pyrolysis was carried out at 800 °C under N2 saturated atmosphere (N2 flow of 0.5 dm3 min 1) during 150 min. The pyrolysis of PS to obtain PS800-150 was meticulously described by Calisto et al. (2014), and a summary of the main properties of this char is displayed in Table 1. A detailed characterization of PS800-150, namely total organic carbon, FTIR, 13C and 1H solid state NMR and SEM analysis may be found elsewhere (Calisto et al., 2014).

2.2. Chemicals and analytic methods Diclofenac sodium (P99%), salicylic acid (P99%) and acetaminophen (P99%) were purchased from Sigma–Aldrich (Steinheim, Germany) while ibuprofen sodium (P98%) was purchased from Fluka. Main properties of these compounds are depicted in Table 2.

The target pharmaceuticals were analyzed by a Jasco HPLC apparatus equipped with a PU-980 pump, a detector UV–Vis Barspec, a phenomenex C18 column (5 lm, 110 Å, 250 4.6 mm), a Rheodyne injector and a 50 lL loop. The wavelengths of detection were 276.5, 220, 236 and 246 for diclofenac, ibuprofen, salicylic acid and acetaminophen,

Table 1 Main properties of primary sludge from the paper industry before (PS) and after pyrolysis (PS800-150) (adapted from Calisto et al. (2014)).

PS

PS800-150

Proximate analysis (wt%) Moisture content Ash Volatile Matter (VM) Fixed Carbon (FC) VM/FC

1.57 55.31 36.09 8.60 4.2

3.16 61.25 20.77 17.98 1.2

Ultimate analysis (wt%) C H N S O

14.83 1.26 0.40 0.29 27.91

27.05 0.82 0.33 0.82 9.73

Physical properties Apparent density (g cm 3) SBET (m2 g 1) Vp (cm3 g 1) W0 (cm3 g 1) L (nm) D (nm)

NM NM NM NM NM NM

0.52 209.12 0.13 0.078 1.30 0.84

Note: Proximate analysis and ultimate analysis are presented on a dry basis (with the exception of the moisture content). Fixed carbon (proximate analysis) and oxygen (ultimate analysis) were calculated by difference. The following abbreviations have been used: Not measured (nm), surface area (SBET), total pore volume (Vp), total micropore volume (W0), average micropore width (L) and average pore diameter (D).

Removal of pharmaceuticals from municipal wastewater

3613

respectively. The mobile phase consisted of a mixture of aceto nitrile:water:orthophosphoric acid (70:30:0.1, v/v/v) for the analysis of diclofenac and salicylic acid, a mixture of metha nol:water:orthophosphoric acid (75:25:0.3) for the analysis of ibuprofen and a mixture of acetonitrile:water (30:70, v/v) for the analysis of acetaminophen. HPLC quality acetonitrile (CH3CN) from LabScan, orthophosphoric acid (H3PO4) from Panreac and ultrapure water obtained by a Millipore System were used for the preparation of the mobile phase. Before use, each mixture was passed through a Millipore 0.45 lm pore size filter and degasified in an ultrasound bath during 30 min.

For the chromatographic determination of concentration, four replicated injections were carried out under a mobile phase flow rate of 1 mL min 1.

2.3. Wastewater from a municipal STP Aiming the practical utilization of pyrolyzed primary pulp mill sludge in tertiary wastewater treatment, adsorption of pharmaceuticals from real wastewater was tested. Thus, for this work, the secondary effluent was collected from the STP of León (Spain). This secondary effluent is directly discharged at the Bernesga river, a tributary of the Esla river that is 77 km long and goes through the town of León. This STP consists of primary and secondary stage treatments. The primary stage comprises the following treatments: screening, sand removal, fat removal and primary clarification. Then, the secondary stage involves a plug-flow activated sludge with nitrification/ denitrification followed by secondary clarification. The plant was designed to treat the wastewater of 330,000 equivalent inhabitants and has an inflow of 123,000 m3 day 1 with a hydraulic retention time (HRT) of about 6 h.

Wastewater quality parameters, namely pH, conductivity, total suspended solids (TSS), biological oxygen demand at five days (BOD5), chemical oxygen demand (DQO), NTK, N-NH4, N-NO3, N-NO2, total P-PO4, were determined by

Table 2

using Standard Methods (APHA-AWWA-WPCF, 2001).

Obtained results are given in Table 3.

2.4. Adsorption experiments Adsorption experiments were performed using a batch experimental approach. For each pharmaceutical, adsorption kinetic experiments were first carried out in order to determine the time necessary to attain equilibria (teq). Then equilibrium experiments were done to determine the corresponding adsorption isotherm. All experiments were carried out by shaking (250 rpm) a known mass of PS800-150 together with 100 mL of wastewater in 250 mL Erlenmeyer flasks. Initial concentration of each target pharmaceutical in wastewater was 100 ± 1 mg L 1. All experiments were done in triplicate and at a constant temperature of 25 ± 2 °C by means of a thermostatically regulated incubator.

Triplicate control experiments, with no adsorbent, were run in parallel with adsorption experiments in order to verify whether the concentration of the target pharmaceutical was stable throughout the duration of the experiments.

In the kinetic experiments, Erlenmeyer flasks were progressively withdrawn from the shaker after pre-set time intervals.

Then, from each flask, three aliquots were taken, filtered and chromatographically analyzed to determine the concentration of the target pharmaceutical. The amount of each pharmaceutical adsorbed onto PS800-150 at each time, qt (mg g 1), was calculated by a mass balance relationship as follows: qt ¼ ðC0 Ct Þ

V W

ð1Þ

where C0 (mg L 1) is the initial liquid-phase concentration of pharmaceutical, Ct (mg L 1) is the liquid-phase concentration of pharmaceutical at a time t (min), V is the volume of the solution (L) and W is the mass (g) of PS800-150.

For equilibrium experiments, Erlenmeyer flasks were shaken during 1000 min in order to guarantee the equilibrium,

Physico-chemical properties of the pharmaceuticals used in this study. Source: ChemSpider

Pharmaceutical (formula)

Structure

Mw (g mol 1)

Swa (mg L 1)

pKa

log Kow

PSA (A2)

HBAC

4

0.57

52.2

3

Diclofenac Sodium (C14H10Cl2NNaO2)

318.13

50,000

Salicylic acid (C7H6O3)

138.12

2240

2.97

2.26

57.5

3

Ibuprofen Sodium (C3H17NaO2)

228.26

100,000

4.91

3.8

40.1

2

Acetaminophen (C8H9NO2)

151.17

14,000

9.48

0.46

49.3

2

PSA = Polar Surface Area.

HBAC = Hydrogen Bound Acceptor Count. a Sw = water solubility (25 °C).

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R.N. Coimbra et al.

Table 3 Main properties of the STP secondary effluent used in this work.

Parameter pH Conductivity (lS cm 1) TSS (mg L 1) BOD5 (mg L 1) COD (mg L 1) NTK (mg L 1) N-NH4 (mg L 1) N-NO3 (mg L 1) N-NO2 (mg L 1) Total P-PO4 (mg L 1)

7.6 ± 0.1 612 ± 3 22 ± 1 21 ± 2 47 ± 3 17 ± 2 13.1 ± 0.4 1.7 ± 0.2 0.5 ± 0.1 1.8 ± 0.1

Note: Each ± stands for standard deviation of three analytical replications.

adsorbed onto PS800-150 at the equilibrium, qe (mg g 1) was calculated by the following mass balance relationship: V ð2Þ qe ¼ ðC0 Ce Þ W For comparison purposes in terms of capacity, equilibrium experiments were also carried out following the same procedure but using ultrapure water as aqueous matrix.

2.5. Modeling of adsorption results The experimental kinetic results were fitted with the pseudo first-order (Lagergren, 1898) and the pseudo second-order (Ho and McKay, 1999) equations. Both the pseudo-first order (Eq. (3)) and the pseudo-second order (Eq. (4)) are empirical rate equations based on the overall sorption rate: qt ¼ qe ð1 e k1 t Þ

as inferred from kinetic results. Then, from each flask, three aliquots were taken, filtered and chromatographically analyzed to determine the equilibrium concentration (Ce, mg L 1) of the target pharmaceutical. The amount of each pharmaceutical

qt ¼

ð4Þ

1 þ qe k2 t

where k1 (min 1) and k2 (mg g 1 min) are the pseudo-first and the pseudo-second order rate constants, respectively.

10

25

ð3Þ

q2e k2 t

(a)

(b)

9 8

20

qt (mg g-1)

qt (mg g-1)

7 15

10

6 5 4 3 Experimental data

Experimental data

5

2 pseudo-first order kinetic equation

pseudo-first order kinetic equation

1

pseudo-second order kinetic equation

pseudo-second order kinetic equation 0

0 0

200

400

600

800

1000

1200

0

200

400

t (min)

(c)

800

1000

1200

(d)

16

14

14

12

12

10

qt (mg g-1)

qt (mg g-1)

16

600

t (min)

8 6

10 8 6

4 2

Experimental data

4

Experimental data

pseudo-first kinetic equation

2

pseudo-first order kinetic equation

pseudo-second kinetic equation

pseudo-second order kinetic equation 0

0 0

200

400

600

t (min)

800

1000

1200

0

200

400

600

800

1000

1200

t (min)

Figure 1 Kinetic results on the removal of (a) diclofenac, (b) salicylic acid, (c) ibuprofen, and (d) acetaminophen from a secondary effluent of a STP by adsorption onto PS800-150. Experimental results throughout time are shown together with the corresponding fittings to the pseudo-first and to the pseudo-second order kinetic equations. Note: error bars stand for standard deviation of three experimental replications.

Removal of pharmaceuticals from municipal wastewater

3615

In order to describe the adsorption equilibrium results, different non-linear models were tried. First of all, fittings to the main two parameter isotherms, namely the Freundlich isotherm (Freundlich, 1906) and the Langmuir isotherm (Langmuir, 1918), which are described by Eqs. (5) and (6), were determined. Then, the Sips isotherm (Sips, 1948), which is a combined form of Langmuir and Freundlich and a three parameter model, as described by Eq. (7), was also tried. qe ¼ KF C1=n e

ð5Þ

qe ¼

Qm K L C e 1 þ KL Ce

ð6Þ

qe ¼

Qm KLF C1=n e 1 þ KLF C1=n e

ð7Þ

where KF is the Freundlich adsorption constant (mg g 1 (mg L 1) 1/n); n is the degree of non-linearity; Qm is the maximum adsorption capacity (mg g 1); KL (L mg 1) and KLF (mg g 1 (mg L 1) 1/n) are the Langmuir and Langmuir– Freundlich affinity coefficients, respectively.

3. Results and discussion The parameters analyzed on the secondary effluent used in this work (Table 3) showed typical values of a municipal STP effluent and accomplished with European regulations on the discharge of this sort of effluents (35 mg L 1 TSS, 25 mg L 1 BOD5 and 125 mg L 1 COD as established by the EU Council Directive 91/271/EEC).

The kinetic experimental data on the adsorption of diclofenac, ibuprofen, salicylic acid and acetaminophen from the secondary effluent of a STP and from ultrapure water are shown in Figs. 1 and 2, respectively, together with fittings to the pseudo-first order and the pseudo-second order kinetic equations. Parameters determined from these fittings are depicted in Table 4.

As it may be seen in Fig. 1, under identical experimental conditions, when the equilibrium is reached, the adsorbed mass of each pharmaceutical on PS800-150 from the secondary effluent was different. Clearly, the drug showing the lowest adsorbed mass is salicylic acid. Furthermore, it is evident that the adsorption of acetaminophen is slower than that of the rest of drugs. Mostly, experimental results are better fitted

10

25

9 8

20

qt (mg g-1)

qt (mg g-1)

7 15

10

6 5 4 3 Experimental data

Experimental data

5

2 pseudo-first order kinetic equation

pseudo-first order kinetic equation

(a)

1

(b)

pseudo-second order kinetic equation

pseudo-second order kinetic equation

0

0 0

200

400

600

800

1000

0

1200

200

400

16

14

14

12

12

10

10

qt (mg g-1)

qt (mg g-1)

16

8 6 4

1000

1200

6 4

pseudo-first kinetic equation

(c)

800

8

Experimental data

Experimental data 2

600

t (min)

t (min)

pseudo-first order kinetic equation

2

(d)

pseudo-second kinetic equation

0

pseudo-second order kinetic equation

0 0

200

400

600

t (min)

800

1000

1200

0

200

400

600

800

1000

1200

t (min)

Figure 2 Kinetic results on the removal of (a) diclofenac, (b) salicylic acid, (c) ibuprofen, and (d) acetaminophen from ultrapure water by adsorption onto PS800-150. Experimental results throughout time are shown together with the corresponding fittings to the pseudo-first and to the pseudo-second order kinetic equations. Note: error bars stand for standard deviation of three experimental replications.

0.007 ± 0.001 13.31 ± 0.17 0.9948 0.31 0.006 ± 0.001 13.50 ± 0.23 0.9914 0.41 0.021 ± 0.003 13.26 ± 0.16 0.9940 0.33 0.038 ± 0.006 12.60 ± 0.13 0.9956 0.27 Note: Each ± stands for standard deviation of three experimental replications.

0.027 ± 0.005 8.36 ± 0.15 0.9912 0.29 0.063 ± 0.015 8.13 ± 0.11 0.9944 0.23 0.042 ± 0.003 20.30 ± 0.06 0.9996 0.13 Pseudo-second order k2 (g mg 1 min 1) qe (mg g 1) R2 Sxy

0.015 ± 0.000 23.64 ± 0.05 0.9998 0.11

0.061 ± 0.004 12.53 ± 0.21 0.9883 0.47 0.052 ± 0.005 12.64 ± 0.31 0.9774 0.66 0.138 ± 0.022 12.68 ± 0.27 0.9720 0.71 0.198 ± 0.033 12.19 ± 0.19 0.9832 0.53 0.129 ± 0.025 8.01 ± 0.22 0.9712 0.52 0.207 ± 0.038 7.94 ± 0.15 0.9861 0.36 0.153 ± 0.017 22.77 ± 0.31 0.9883 0.82 0.235 ± 0.130 19.94 ± 0.02 0.9971 0.36

UP-W STP-SE STP-SE UP-W STP-SE

UP-W

STP-SE

UP-W

Acetaminophen Ibuprofen Salicylic acid Diclofenac

Pharmaceuticals

Pseudo-first order k1 (min 1) qe (mg g 1) R2 Sxy

Table 4

by the pseudo-second order equation than by the first order one, which is confirmed by the R2 and Syx values in Table 4.

The kinetic constant k2 decreases from salicylic acid > diclofenac > ibuprofen > acetaminophen. Furthermore, the k2 corresponding to the adsorption of acetaminophen is an order of magnitude lower than the k2 determined for the adsorption of the other pharmaceuticals here considered. On the other hand, the fitted qe for the adsorption of salicylic acid is an order of magnitude lower than for the rest of drugs.

Kinetic results on the adsorption of the considered pharmaceuticals from ultrapure water are given in Fig. 2. As for the adsorption from the secondary effluent, fittings to the pseudosecond order equation are better than those to the pseudo-first order one; salicylic acid was the one showing the lowest adsorbed equilibrium concentration (qe), which was an order of magnitude lower than for the rest of pharmaceuticals; and the adsorption of acetaminophen was the slowest one with a k2 an order of magnitude lower than for the rest of drugs. From ultrapure water, the kinetic constant k2 also decreases from salicylic acid > diclofenac > ibuprofen > acetaminophen. When comparing the adsorption kinetics of each pharmaceutical from wastewater (Fig. 1) with its adsorption from ultrapure water (Fig. 2), differences are not especially relevant as confirmed by the pseudo-second order kinetic parameters in Table 4. Equilibrium was attained quite quickly from either the STP secondary effluent or ultrapure water, for all the pharmaceuticals equilibrium being attained within 200 min. In any case, under the experimental conditions here used, the kinetic constant k2 was slightly higher (diclofenac, salicylic acid, ibuprofen) or equal (acetaminophen) for the adsorption from the secondary STP effluent than from ultrapure water. On the other hand, the adsorbed concentration in the equilibrium (qe) was slightly higher (diclofenac, ibuprofen) or equivalent (salicylic acid, acetaminophen) from ultrapure than from the secondary STP effluent.

The equilibrium experimental data on the adsorption of diclofenac, ibuprofen, salicylic acid and acetaminophen from the secondary STP effluent and from ultrapure water are shown in Figs. 3 and 4, respectively, together with fittings to the isotherm models considered. Parameters determined from these fittings are depicted in Table 5.

The equilibrium isotherms obtained for the adsorption of the pharmaceuticals from the STP effluent (Fig. 3) show some differences regarding the adsorption capacity and shape of isotherm. The adsorption capacity decreases from diclofenac > ibuprofen acetaminophen > salicylic acid. These capacity differences must be related to the drugs properties, among which Sw and log Kow seem to have been especially determinant (Calisto et al., 2015). With respect to the isotherm, fittings to the Sips model are the most accurate for diclofenac, ibuprofen and acetaminophen. However, for salicylic acid, ambiguous fittings to the Sips isotherm were obtained, while both the Langmuir and, especially, the Freundlich isotherm models fitted experimental results. These observations are confirmed by parameters in Table 5, which make evident differences between the capacity and the isotherm model fittings.

As shown in Fig. 4, the adsorption equilibrium of pharmaceuticals from ultrapure water mostly resembles their adsorption from the STP secondary effluent. The equilibrium capacity also decreases from diclofenac > ibuprofen acetaminophen > salicylic acid and the Sips isotherm model

R.N. Coimbra et al.

Kinetic parameters obtained from the fittings of experimental results on the adsorption of each pharmaceutical to the pseudo-first and to the pseudo-second order equations.

3616

Removal of pharmaceuticals from municipal wastewater 25

3617 10

(a)

(b)

9 8

20

15

qe (mg g-1)

qe (mg g-1)

7

10 Experimental data

20

40

60

Experimental data Freundlich

1

Sips 0

4

2

Langmuir 0

5

3

Freundlich

5

6

Langmuir

0 80

100

0

20

16

(c)

14

14

12

12

10

10

qe (mg g-1)

qe (mg g-1)

16

8 6

40

6

Experimental data Freundlich

Freundlich

4

2

Langmuir

2

0

Sips

0

40

100

8

4

20

80

(d)

Experimental data

0

60

Ce (μg L-1)

Ce (μg L-1)

60

Langmuir Sips

80

100

Ce (μg L-1)

0

20

40

60

80

100

Ce (μg L-1)

Figure 3 Equilibrium results on the removal of (a) diclofenac, (b) salicylic acid, (c) ibuprofen, and (d) acetaminophen from a secondary effluent of a STP by adsorption onto PS800-150. Experimental results are shown together with fittings to the Freundlich, to the Langmuir and to the Sips isotherm models. Note: error bars stand for standard deviation of three experimental replications.

is the one that better fits experimental results, except for salicylic acid. In this last case, the best fittings were obtained by the Freundlich isotherm model. Parameters in Table 5 support these remarks, as it may be seen by the Qm and the R2 and Syx obtained for each pharmaceutical.

When comparing the equilibrium isotherms obtained for the adsorption of the considered pharmaceuticals from the STP secondary effluent and ultrapure water, differences are not outstanding. Focusing on the Sips isotherm model parameters (Table 5) for comparing the adsorption of diclofenac, ibuprofen and acetaminophen, several remarks may be made.

First, considering the associated deviations, the Qm values determined for the adsorption from the STP effluent and from ultrapure water are equivalent. In the case of the KLF, which is usually related to the affinity of the adsorbent toward the adsorbate, each pharmaceutical showed a different pattern.

Equal KLF were determined for diclofenac while higher values were determined in ultrapure water than in the STP secondary effluent for ibuprofen and acetaminophen. Therefore, it may be inferred that the adsorption affinity for these last pharmaceuticals may be affected by the complex matrix of the STP effluent.

Finally, the shape of the adsorption isotherms revealed a favorable process, with n > 1, which points to the fact that the adsorbents are efficient not only removing high but also low concentrations of these pharmaceuticals. In any case, higher n values were determined for the adsorption of these pharmaceuticals from ultrapure water than from the STP effluent. With respect to salicylic acid, the Freundlich isotherm parameters in Table 5 will be used for the comparison of its adsorption from the two different aqueous matrixes. In terms of adsorption affinity, a higher salicylic acid adsorption coefficient KF was obtained for the adsorption from ultrapure water. In the case of n, it was larger than 1 either from ultrapure water or from the STP secondary effluent, but a larger value was determined for the adsorption from ultrapure water. Therefore, some matrix effects must have affected the salicylic acid adsorption from the STP effluent. In any case, as it was for the rest of the pharmaceuticals, the adsorption capacity remained the same from both ultrapure water and the STP secondary effluent, which is a key issue for the application of the charcoal here produced for an adsorptive tertiary treatment of wastewater.

3618

R.N. Coimbra et al.

25

10

(a)

(b)

9 20

8

qe (mg g-1)

qe (mg g-1)

7 15

10

6 5 4

Experimental data

Experimental data 3 Freundlich

Freundlich

5

2

Langmuir

1

Sips

0 0

20

40

60

Langmuir

0 80

0

100

20

16

(c)

14

14

12

12

10

10

qe (mg g-1)

qe (mg g-1)

16

8 6

40

6

Experimental data

4

Freundlich

Freundlich

2

Langmuir

2

0

Sips

0

40

100

8

4

20

80

(d)

Experimental data

0

60

Ce (μg L-1)

Ce (μg L-1)

60

Langmuir Sips

80

100

Ce (μg L-1)

0

20

40

60

80

100

Ce (μg L-1)

Figure 4 Equilibrium results on the removal of (a) diclofenac, (b) salicylic acid, (c) ibuprofen, and (d) acetaminophen from ultrapure water by adsorption onto PS800-150. Experimental results are shown together with fittings to the Freundlich, to the Langmuir and to the Sips isotherm models. Note: error bars stand for standard deviation of three experimental replications.

Our results differ from those by Sotelo et al. (2012), who determined the adsorption isotherms of diclofenac and isoproturon using three carbonaceous materials (activated carbon, multiwalled carbon nanotubes and carbon nanofibers), found that the single adsorption capacity of these drugs was higher in ultrapure water than in real wastewater. Similarly, Kovalova et al. (2013) determined the adsorption isotherm and batch kinetic data using two powdered activated carbons to assess the removal of the pharmaceuticals 5-fluorouracil (5Fu) and cytarabine (CytR) from ultrapure water and from a wastewater treatment plant effluent. These authors (Sotelo et al., 2012; Kovalova et al., 2013) found that the presence of organic matter in wastewater lowered the pharmaceuticals adsorption uptake. Using natural organic matter (NOM), Saravia and Frimmel (2008) showed that its presence slightly reduced the adsorption of pharmaceuticals, namely carbamazepine, clofibric, diclofenac, and iohexol on activated carbon. On the contrary, Méndez-Dı́az et al. (2012) found that an increased adsorption capacity of phthalic acid (PA) from wastewater than from ultrapure water occurred onto two different activated carbons, which was attributed to the action of

microorganisms in wastewater. In fact, Combarros et al.

(2014) proved that the formation of bacterial biofilm on the surface of a commercial activated carbon increased the adsorptive removal of salicylic acid from water. In fact, it is possible that the synergetic microorganism action may have compensated the competitive effect of organic matter so that the removal capacity remains the same when using the produced charcoal for the removal of diclofenac, salicylic acid, ibuprofen and acetaminophen. It must be highlighted that, it was verified in this work that the pharmaceuticals concentration in controls (ultrapure or STP secondary effluent, in the absence of charcoal) remained constant throughout the duration of all the experiments.

Unfortunately, no other than the here referred works have been found in the literature on the comparative kinetics or isotherms in ultrapure and wastewater for the adsorption of pharmaceuticals. Therefore, it is not possible to further contrast our findings with results by other authors and with other adsorbent materials. From our point of view, this sort of study is essential for the application of any adsorbent in the tertiary treatment of wastewater.

Pharmaceuticals Diclofenac

Salicylic acid

Ibuprofen

Acetaminophen

STP-SE

UP-W

STP-SE

UP-W

STP-SE

UP-W

STP-SE

UP-W

Freundlich KF (mg g 1 (mg L 1) 1/n) n R2 Syx

3.07 ± 0.31 2.32 ± 0.14 0.9744 1.10

3.70 ± 0.36 2.41 ± 1.40 0.9805 1.18

0.50 ± 0.04 1.62 ± 0.04 0.9949 0.19

0.90 ± 0.05 1.97 ± 0.05 0.9954 0.17

2.55 ± 0.29 2.76 ± 0.22 0.9617 0.731

4.91 ± 0.29 4.36 ± 0.31 0.9534 0.77

2.86 ± 0.38 2.73 ± 0.27 0.9438 1.07

3.95 ± 0.31 3.66 ± 0.28 0.9720 0.73

Langmuir Qm (mg g 1) KL (L mg 1) R2 Syx

23.38 ± 1.28 0.058 ± 0.009 0.9714 1.16

26.69 ± 1.53 0.060 ± 0.012 0.9643 1.61

15.12 ± 1.06 0.013 ± 0.002 0.9875 0.29

12.08 ± 1.99 0.025 ± 0.005 0.9622 0.48

12.93 ± 0.45 0.098 ± 0.014 0.9739 0.60

12.66 ± 0.30 0.359 ± 0.046 0.9580 0.73

15.53 ± 0.71 0.077 ± 0.012 0.9721 0.76

12.33 ± 0.65 0.265 ± 0.077 0.9303 1.15

Sips Qm (mg g 1) KLF (mg g 1 (mg L 1) 1/n) n R2 Syx

34.84 ± 8.44 0.069 ± 0.012 1.49 ± 0.21 0.9852 0.88

53.16 ± 22.62 0.062 ± 0.022 1.77 ± 0.29 0.9845 1.10

16.05 ± 2.30 0.118 ± 0.017 1.38 ± 0.22 0.9824 0.52

15.36 ± 1.05 0.372 ± 0.035 1.69 ± 0.20 0.9851 0.45

16.79 ± 2.25 0.092 ± 0.021 1.15 ± 0.21 0.9734 0.77

19.74 ± 4.55 0.230 ± 0.063 2.15 ± 0.379 0.9846 0.57

Removal of pharmaceuticals from municipal wastewater

Table 5 Isotherm parameters obtained from the fittings of experimental results on the adsorption of each pharmaceutical from the secondary effluent of a STP (STP-SE) or from ultrapure water (UP-W).

Note: Each ± stands for standard deviation of three experimental replications.

3619

3620 4. Conclusions A charcoal, obtained by the pyrolysis of primary pulp mill sludge, was proved to be able to adsorb diclofenac, salicylic acid, ibuprofen and acetaminophen either from ultrapure or from an STP secondary effluent. Adsorption equilibrium of these pharmaceuticals was attained within 200 min in all cases, the kinetics being described by the pseudo-second order equation. Both from ultrapure water and from the STP secondary effluent, the kinetic constant k2 decreased from salicylic acid > diclofenac > ibuprofen > acetaminophen.

Equilibrium results were appropriately described by the Sips isotherm model, except for salicylic acid, adsorption equilibrium of which was better described by the Freundlich isotherm. Both from ultrapure water and from the STP secondary effluent, the adsorption capacity decreased from diclofenac > ibuprofen acetaminophen > salicylic acid. For each of these pharmaceuticals, neither the removal velocity nor the capacity decreased when using the produced charcoal in a real wastewater matrix with respect to its utilization in ultrapure water.

Competitive effects of substances present in wastewater may have been compensated by the synergetic removal of pharmaceuticals by microorganisms.

Acknowledgments Vânia Calisto and Catarina I.A. Ferreira thank the Portuguese Science Foundation (FCT) for their postdoctoral (SFRH/ BPD/78645/2011) and PhD grants (SFRH/BD/88965/2012), respectively. Marta Otero acknowledges financial support from the Spanish Ministry of Economy and Competitiveness, State Secretariat for Research, Development and Innovation (RYC-2010-05634). European Funds through COMPETE and by National Funds through the FCT within project PEst-C/MAR/LA0017/2013 are acknowledged. Authors also thank the kind collaboration of Eng Pedro Sarmento from RAIZ – Instituto de Investigação da Floresta e do Papel.

References APHA-AWWA-WPCF, 2001. Standard Methods for the Examination of Water and Wastewater, 20th ed. American Public Health Association, Washington DC, USA. Bolong, N., Ismail, A.F., Salim, M.R., Matsuurad, T., 2009. A review of the effects of emerging contaminants in wastewater and options for their removal. Desalination 239, 229–246.

Calisto, V., Ferreira, C.I.A., Santos, S.M., Gil, M.V., Otero, M., Esteves, V.I., 2014. Production of adsorbents by pyrolysis of paper mill sludge and application on the removal of citalopram from water. Bioresource Technol. 166, 335–344.

Calisto, V., Ferreira, C.I.A., Oliveira, J.A.B.P., Otero, M., Esteves, V. I., 2015. Adsorptive removal of pharmaceuticals from water by commercial and waste-based carbons. J. Environ. Manage. 152, 83–90.

CEPI, 2013. Confederation of European Paper Industries (CEPI).

CEPI’S Online Sustainability Report. <http://www.cepi-sustainability.eu/> (last accessed on the 15th of January 2015).

Combarros, R.G., Rosas, I., Lavı́n, A.G., Rendueles, M., Dı́az, M., 2014. Influence of biofilm on activated carbon on the adsorption and biodegradation of salicylic acid in wastewater. Water Air Soil Poll. 225, 1858–1869.

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Domı́nguez, J.R., González, T., Palo, P., Cuerda-Correa, E., 2011.

Removal of common pharmaceuticals present in surface waters by Amberlite XAD-7 acrylic-ester-resin: influence of pH and presence of other drugs. Desalination 269, 231–238.

Elliott, A., Mahmood, T., 2005. Survey benchmarks generation, management of solid residues. Pulp Pap. 79, 49–55.

Farré, M., Pérez, S., Kantiani, L., Barceló, D., 2008. Fate and toxicity of emerging pollutants, their metabolites and transformation products in the aquatic environment. Trends Anal. Chem. 27, 991–1007.

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Chem. 57, 385–470.

Ho, I.S., McKay, G., 1999. Pseudo-second order model for sorption processes. Process Biochem. 34, 451–465.

Ince, B.K., Cetecioglu, Z., Ince, O., 2011. Pollution Prevention in the Pulp and Paper Industries, Environmental Management in Practice, Dr. Elzbieta Broniewicz (Ed.), ISBN: 978-953-307-358-3, InTech, DOI: 10.5772/23709. <http://www.intechopen.com/ books/environmental-management-in-practice/pollution-prevention-in-the-pulp-and-paper-industries> (last accessed on the 19th of November 2015).

Kovalova, L., Knappe, D.R.U., Lehnberg, K., Kazner, C., Hollender, J., 2013. Removal of highly polar micropollutants from wastewater by powder activated carbon. Environ. Sci. Poll. Res. 20, 3607–3615.

Lagergren, S., 1898. Zur theorie der sogenannten adsorption gelöster stoffe. Kungliga Svenska Vetenskapsakademiens. Handlingar 24, 1–39.

Langmuir, I., 1918. The adsorption of gases on plane surfaces of glass, mica and platinum. J. Am. Chem. Soc. 40, 1361–1403.

Méndez, A., Fidalgo, J.M., Guerrero, F., Gascó, G., 2009. Characterization and pyrolysis behaviour of different paper mill waste materials. J. Anal. Appl. Pyrol. 86, 66–73.

Méndez-Dı́az, J.D., Abdel daiem, M.M., Rivera-Utrilla, J., SánchezPolo, M.Bautista-Toledo, I., 2012. Adsorption/bioadsorption of phthalic acid, an organic micropollutant present in landfill leachates, on activated carbons. J. Colloid Interface Sci. 369, 358–365.

Monte, M.C., Fuente, E., Blanco, A., Negro, C., 2009. Waste management from pulp and paper production in the European Union. Waste Manage. 29, 293–308.

Pokhrel, D., Viraraghavan, T., 2004. Treatment of pulp and paper mill wastewater- a review. Sci. Total Environ. 333, 37–58.

Priac, A., Morin-Crini, N., Druart, C., Gavoille, S., Bradu, C., Lagarrigue, C., Torri, G., Winterton, P., Crini, G., 2014. Alkylphenol and alkylphenol polyethoxylates in water and wastewater: a review of options for their elimination. Arab. J. Chem. http://dx. doi.org/10.1016/j.arabjc.2014.05.011.

Ridout, A.J., Carrier, M., Görgens, J., 2015. Fast pyrolysis of low and high ash paper waste sludge: influence of reactor temperature and pellet size. J. Anal. Appl. Pyrol. 111, 64–75.

Santos, L.H.M.L.M., Araujo, A.N., Fachinia, A., Pena, A., DelerueMatos, C., Montenegro, M.C.B.S.M., 2010. Review. Ecotoxicological aspects related to the presence of pharmaceuticals in the aquatic environment. J. Hazard Mater. 175, 45–95.

Saravia, F., Frimmel, F.H., 2008. Role of NOM in the performance of adsorption-membrane hybrid systems applied for the removal of pharmaceuticals. Desalination 224, 168–171.

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Sotelo, J.L., Rodrı́guez, A.R., Mateos, M.M., Hernández, S.D., Torrellas, S.A., Rodrı́guez, J.G., 2012. Adsorption of pharmaceutical compounds and an endocrine disruptor from aqueous solutions by carbon materials. J. Environ. Sci. Health – Part B. Pestic. Food Contam. Agric. Wastes 47, 640–652.

Yang, Y., Brammer, J.G., Ouadi, M., Samanya, J., Hornung, A., Xu, H.M., Li, Y., 2013. Characterisation of waste derived intermediate pyrolysis oils for use as diesel engine fuels. Fuel 103, 247–257.

PAPERmaking!

O THE PUBLISHERS U S S OF O PAPER TECHNOLOGY INTERNATIONAL FROM

Volume 6, Number 1, 2020

Specific Energy Consumption / Use (SEC) in Energy Management for Improving Energy Efficiency in Industry: Meaning, Usage and Differences Akvile Lawrence, Patrik Thollander, Mariana Andrei and Magnus Karlsson.

Although several research studies have adopted specific energy consumption (SEC) as an indicator of the progress of improved energy efficiency, publications are scarce on critical assessments when using SEC. Given the increasing importance of monitoring improved industrial energy efficiency and the rising popularity of SEC as an energy key performance indicator (e-KPI), an in-depth analysis and problematization on the pros and cons of using SEC would appear to be needed. The aim of this article is to analyse SEC critically in relation to industrial energy efficiency. By using SEC in the pulp and paper industry as an example, the results of this exploratory study show that although SEC is often used as an e-KPI in industry, the comparison is not always straightforward. Challenges emanate from a lack of information about how SEC is calculated. It is likely that SEC is an optimal e-KPI within the same study, when all deployed SECs are calculated in the same way, and with the same underlying assumptions. However, before comparing SEC with other studies, it is recommended that the assumptions on which calculations are based should be scrutinized in order to ensure the validity of the comparisons. The paper remains an important contribution in addition to the available handbooks.

Contact information: Department of Management and Engineering, Division of Energy Systems, Linköping University, SE-58183 Linköping, Sweden Energies 2019, 12, 247 doi:10.3390/en12020247 This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

The Paper Industry Technical Association (PITA) is an independent organisation which operates for the general benefit of its members – both individual and corporate – dedicated to promoting and improving the technical and scientific knowledge of those working in the UK pulp and paper industry. Formed in 1960, it serves the Industry, both manufacturers and suppliers, by providing a forum for members to meet and network; it organises visits, conferences and training seminars that cover all aspects of papermaking science. It also publishes the prestigious journal Paper Technology International and the PITA Annual Review, both sent free to members, and a range of other technical publications which include conference proceedings and the acclaimed Essential Guide to Aqueous Coating.

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Article 9 – Energy Efficiency Issues

energies Article

Specific Energy Consumption/Use (SEC) in Energy Management for Improving Energy Efficiency in Industry: Meaning, Usage and Differences Akvile Lawrence *, Patrik Thollander *, Mariana Andrei * and Magnus Karlsson * Department of Management and Engineering, Division of Energy Systems, Linköping University, SE-58183 Linköping, Sweden * Correspondence: akvile.lawrence@liu.se or akvile.lawrence@gmail.com (A.L.); patrik.thollander@liu.se (P.T.); mariana.andrei@liu.se (M.A.); magnus.karlsson@liu.se (M.K.) Received: 7 December 2018; Accepted: 9 January 2019; Published: 15 January 2019

Abstract: Although several research studies have adopted specific energy consumption (SEC) as an indicator of the progress of improved energy efficiency, publications are scarce on critical assessments when using SEC. Given the increasing importance of monitoring improved industrial energy efficiency and the rising popularity of SEC as an energy key performance indicator (e-KPI), an in-depth analysis and problematization on the pros and cons of using SEC would appear to be needed. The aim of this article is to analyse SEC critically in relation to industrial energy efficiency. By using SEC in the pulp and paper industry as an example, the results of this exploratory study show that although SEC is often used as an e-KPI in industry, the comparison is not always straightforward. Challenges emanate from a lack of information about how SEC is calculated. It is likely that SEC is an optimal e-KPI within the same study, when all deployed SECs are calculated in the same way, and with the same underlying assumptions. However, before comparing SEC with other studies, it is recommended that the assumptions on which calculations are based should be scrutinized in order to ensure the validity of the comparisons. The paper remains an important contribution in addition to the available handbooks.

Keywords: specific energy consumption; specific energy use; specific energy; SEC; energy management; energy efficiency; industry; energy use; manufacturing

Highlights

• • • • •

SEC is based on assumptions.

Assumptions for SEC calculations are rarely given.

SEC is used optimally for comparison when SEC calculations are uniform.

SEC is most reliable when calculated within the same study using continuous process data.

SEC emanating from a variety of individual case studies should be used with caution.

1. Introduction In order to reach the goal of reducing greenhouse gas (GHG) emissions by 80–95% by 2050 compared to 1990 levels, industry has to improve its energy efficiency [1]. Improving energy efficiency is considered to be the most promising measure to mitigate climate change [2]. The global industrial sector accounted for ~42.8 EWh (~154 EJ) in 2014, of which Organization for Economic Co-operation and Development (OECD) countries accounted for 69% (~29.5 EWh) of the global industrial energy end-use [3]. In this context, energy management is of great importance as it aims to reduce companies’ energy use and associated energy costs continuously [4].

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As energy management is an important means by which to improve energy efficiency, the use of specific energy consumption (SEC) to identify potential improvements in energy efficiency is seen as an important instrument of energy management. Frequently, in both literature and international standards, SEC is used as an energy performance indicator to evaluate or measure the performance of energy efficiency. For example, Peng et al. [5] used SEC to evaluate changes in energy efficiency in the Chinese pulp and paper industry (PPI) over the period between 1985 and 2010, and Lawrence et al. [6] used SEC to investigate the possible effects of firm characteristics on energy efficiency in the PPI in Sweden. Furthermore, Fleiter et al. [7] used SEC to study energy efficiency in the German PPI and to assess the potential for energy savings, while Farla et al. [8] used SEC to portray changes in energy efficiency in the PPI. SEC is also used for benchmarking, although some concerns about SEC usage in benchmarking have been raised. Although the European standard on energy efficiency benchmarking (16231:2012) [9] provides the methodology needed for collecting and analysing energy data for energy efficiency benchmarking, the standard barely problematizes the challenges involved in using SEC for this purpose. For instance, Farla et al. [8] pointed out that “using the SECs from one country in a cross-country analysis may lead to distortions if the SECs for some of the products are relatively high (due to inefficient processes)” ([8], p. 748). Another example is found in Laurijssen et al. [10], where the authors used SEC to benchmark energy use at process unit level in the paper industry. Additionally, SEC can be used indirectly as in e.g., a study by Phylipsen et al. [11], where SEC was used to calculate an energy efficiency index (EEI), i.e., the ratio between the actual SEC and the reference SEC to explore the impact when the best available technologies (BATs) are used.

Despite the widespread use of SEC as an indicator for energy efficiency, critical scientific papers on SEC seem—in the authors’ opinion—to be almost lacking. Three exceptions are an in-depth review on energy efficiency including SEC written by Patterson [12] and methodologies for international comparisons of energy efficiency by Phylipsen et al. [13], both published more than two decades ago, and a recent study addressing industrial energy benchmarking in the PPI by Rogers et al. [14].

In summary, although several research studies have adopted SEC as an indicator for the progress of improved energy efficiency, publications on critical assessments when using SEC are scarce. But at the same time, the international standard on energy management systems (ISO 50006:2017) [15] provides general principles and guidance on how a company can establish energy performance indicators and energy baselines for measuring its energy performance. Given the increasing importance of monitoring improved industrial energy efficiency and the rising popularity of SEC as an energy key performance indicator (e-KPI), an in-depth analysis and problematization of the pros and cons of using SEC would appear to be needed. The aim of this article is to critically analyse SEC in relation to industrial energy efficiency.

2. Background The variable characterizing energy use per produced product and expressed as a ratio of thermodynamic units per physical unit is often referred to in literature as specific energy consumption (e.g., [8,12,16]). The meaning of SEC is to portray how much energy is used for producing a unit of product. SEC is perhaps used due its convenience, i.e., the amount of energy can be directly reported per amount of product. Generally, SEC is calculated by dividing the amount of energy used with the amount of products. However, both, products and energy carriers are often chosen arbitrarily depending on the intended purpose of using SEC. For example, SEC can be calculated for the total amount of products or for individual products from the product mix. Similarly, SEC can be calculated for the total primary energy used or for specific energy carriers, e.g., how much electricity and heat separately has been used for producing a unit of product. SEC in international standards, such as e.g., ISO 50006:2017 [17], is recommended for being used as an energy performance indicator, since SEC allows measurement of the energy performance and thus the performance of benchmarking. Benchmarking of energy use in industry is the process of comparing and evaluating energy performance, where SEC can be used for benchmarking at various levels: process, site, national

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and international benchmarking as in e.g., study by Andersson et al. [18]. Data for rough calculations of SEC is sometimes publicly available in larger companies’ annual sustainability reports. Despite the convenience of using SEC, several challenges have been pointed out in the literature (Table 1). Some solutions have also been presented. For example, Phylipsen et al. [11] use ratios between the actual SEC and the sector-specific reference SEC—the energy efficiency index.

Table 1. Examples of difficulties that have been cited in some of the references using specific energy consumption (SEC). DC—Developing countries.

Type of Difficulty

Difficulties in Citations

Reference

Page

Availability of information

“Tracking of energy efficiency improvements in pulp and paper manufacturing is difficult, because publicly available data on production, capacity and energy use are limited. Additionally, some countries do not report biomass use for the pulp and paper sector, which makes it difficult to get an accurate picture of the sector’s energy needs.”

[3]

42

Availability of information

“Difficulties in finding relevant data are related to difficulties in comparing production processes and end products.”

[8]

755

Complexity of integrated processes

“One difficulty of finding a set of SECs for the best available techniques is the fact that process steps in the pulp and paper industry are usually integrated.

Therefore it is difficult to attribute part of the total energy consumption to any of the products.”

[8]

749

Partitioning of products

“The measurement of energy efficiency in terms of physical-thermodynamic indicators is not as straightforward as it first appears because of the so-called joint production or partitioning problem. This refers to the difficulty in allocating one energy input to several outputs in an industry. [...] The problem arises when the energy input (ΔH) has to be allocated to the different outputs (tonnes) in order to generate the desired indicators.”

[12]

381

Assumptions, definition of final output, e.g., sold products or all produced products?

“ . . . what constitutes a useful energy output. The definition of useful implicitly requires some assignment of human values in order to define what is considered to be a useful output.”

[12]

383

Availability and quality of information

“In general, availability of plant data from DCs is limited. [ . . . ] Literature data is scattered and problematic.”

[19]

6663

Variation over time and among countries

“Comparing energy efficiency between countries is not straightforward because of differences in economic structure. Also within a country, the economic structure can change over time.”

[11]

665

Additionally, there are general aspects affecting the SEC. The age of equipment and the plant itself are some of the aspects that can affect SEC. For example, although newer equipment tends to be more energy-efficient compared to older equipment, it can take a few years to optimize the new equipment after installing it [20]. The location of the plant can also have an effect on SEC, i.e., environmental conditions affect heat demand [20]. Additionally, the size of the plant, for example the width of the paper machine [20] and the production rate ([20,21]), are also variables that affect SEC. Some of the challenges regarding SEC are also faced by other energy use related fields, e.g., when calculating energy returned on energy invested (EROI) (e.g., [22–27]).

Regarding benchmarking, different levels of analysis require different amounts of data. Generally, the more detailed benchmarking is, the more data is required [28]. SEC is one of the methods used for energy benchmarking at multi-national level, national/regional level, site level and process level, where SEC has been used most frequently in benchmarking studies at process level according to the results presented by Andersson et al. [18]. Further, the current average SEC is the preferred indicator for information about energy efficiency at regional or country level, provided that adequate data is available (according to [19]).

3. Data and Methods This article was inspired by the authors’ own experiences of using SEC to research industrial energy efficiency and can, therefore, be said to be explorative in nature. Specifically, this article was inspired by experiences while studying SEC to research industrial energy efficiency and factors tending to affect the energy efficiency as well as by research addressing energy management and

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energy efficiency, where SEC is commonly used as an e-KPI. Examples of how many and what type of companies that have been studied in the PPI are 48 pulp and paper mills in Sweden 2006–2015 [6] and 40 pulp and paper mills in Sweden [29]. Examples of other industrial companies that have been studied are 27 foundries in Sweden [30], 65 foundries in Europe ([31,32]), 23 iron and steel mills in Sweden [33], 21 industrial companies in Sweden [34], 11 sawmills [18], and 8 manufacturing firms in Sweden [35]. A database containing data about the use of individual energy carriers and individual pulp and paper products by individual PPI mills in Sweden since 2002 is used, among others studying SEC, for [6]. The rest of the named studies were conducted by collecting data by questionnaires and/or interviews as well as complementing by data from databases in some studies.

The results are based on a literature search using Linköping University Library’s literature search system—UniSearch—that was described in detail in Lawrence et al. [36]. UniSearch contains publications that also available through the Web of Science, Scopus, ScienceDirect, etc. In brief, SEC was searched for within those studies that primarily addressed energy management in the pulp and paper industry. Additionally, the snowball method was applied, whereby e.g., publications that referred to other studies using SEC were also included. The literature search was limited to English-language, peer-reviewed, full-text literature accessible via UniSearch in November 2018.

In addition to the scientific review, several standards were reviewed in relation to the meaning and usage of SEC as an energy performance indicator: SS-ISO 50001:2011 (energy management systems [15]), SS-ISO 50006:2017 (energy management systems—measuring energy performance using energy baselines (EnB) and energy performance indicators (EnPI) [17]), SS 16212:2012 (energy efficiency and savings calculations, top-down and bottom-up methods [37]) and SS 16231:2012 (energy efficiency benchmarking methodology [9]).

SEC in the PPI has been used as an example to illustrate the differences in SEC. The PPI was chosen as an example because it is one of the five most energy-intensive industries globally [3]. In fact, the PPI may account for as much as 5.6% of the global industrial energy end-use [3]. With today’s attempts to achieve a sustainable circular economy, and given the renewable nature of the resources for production, pulp and paper production is likely to increase. Additionally, the PPI is facing challenges in terms of remaining competitive, where the energy efficiency improvement is seen as one of the most effective strategies for remaining competitive in some countries (e.g., [38]).

In this study, when needed, primary energy factors (PEFs) and SEC were calculated by dividing the sum of gross electricity produced plus imported/exported electricity, by net electricity used in the country (e.g., [6]). If the SEC in the references was given in units other than the GWh/kt, then the units were converted. Additionally, when the use of energy carriers was given in the references, e.g., use of electricity and heat, then the usage of the primary energy was calculated by using 2.5 as the PEF. PEF of 2.5 means that the generating efficiency for final energy carrier is 40% and implies that 2.5 units of primary energy carriers generate 1 unit of final energy carrier, e.g., electricity. In this study we presented PEF, therefore, if final energy generating efficiency was presented in a reference, such as that the efficiency for generating electricity was 40% in ref. [8], it was recalculated to PEF. In cases where the total energy used was already presented in the references without specifying the PEF used to calculate it, not specified (n.s.) is noted.

4. Results and Discussion 4.1. The Meaning of Specific Energy Consumption (SEC) SEC is a widespread term used by international energy agencies, e.g., [3], and in research studies, e.g., [38]. Nevertheless, energy can only be converted from one form to another or transferred among systems, and cannot be destroyed or created ([39,40]). According to the first law of thermodynamics: “Although energy assumes many forms, the total quantity of energy is constant, and when energy disappears in one form it appears simultaneously in other forms” ([39], p. 22). Thus, energy cannot be “consumed” as such. It is the exergy, i.e., the measure of the quality and quantity of energy, that

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is available for use [40]. However, exergy is rarely, if at all, mentioned in the literature addressing energy management and using SEC. Instead, the same variable expressed in thermodynamic units per physical units is most often referred to as specific energy consumption. The wording of the term can be misinterpreted, because it is the exergy that is used during the process—the part of the energy that is available to be used for work. Some studies refer to the same term as “typical energy demand”, e.g., power demand and heat demand per paper grade [38] or SEC—specific energy demand [41].

In conclusion, it would be better to use the thermodynamically correct names, i.e., specific exergy consumption or specific energy use. Nevertheless, although specific exergy consumption and specific energy use are thermodynamically correct, it could be possible in theory that the change of names could cause some unforeseen/unintended challenges.

4.2. Calculations of SEC Generally (e.g., [8]), SEC is calculated as a ratio of energy used for producing a product: SEC =

Energy used Product s amount

(1)

Units are seemingly chosen arbitrarily depending on the intended usage of SEC, e.g., GJ/t for heat (e.g., [10]), and GWh/kt for electricity (e.g., [6]). When calculating the total energy, including electricity and heat, units are also chosen arbitrarily depending on the purpose of the study. For example, GJ/tonne as in e.g., [8,10], while Lawrence et al. [6] used GWh/kt because some of the large companies also used GWh/kt for their SEC in their annual reports (e.g., [42,43]).

Calculation of SEC as presented in the Equation (1) is generic, meaning that generally SEC is calculated as a ratio between the energy used and a unit of product. However, Equation (1) can be modified if needed for specifying the type of energy carriers and/or product. For example, Farla et al. [8] calculated SEC for one single individual product for one single individual process as: SECx =

Ex Px

(2)

In Equation (2), Ex—the energy use of the single individual manufacturing process x and Px—physical unit of a single individual product x. Meanwhile aggregated SEC (SECagg) for a group of products, e.g., for a sector, can be calculated as a ratio of the sum of all the energy used with the sum of all the products produced, providing the production output has the same composition during the time that is to be compared [8]: SECagg =

∑E ∑P

(3)

In Equation (3), ∑E—sum of all the energy used and ∑P—sum of physical units of all products.

Following the principles of Equations (1)–(3), in order to evaluate the usage of individual energy carriers for individual products or a sum of products the individual energy carriers can be used instead. For instance De Beer et al. [16] calculated SEC for electricity and SEC for heat. Furthermore, Laurijssen et al. [10], calculated specific primary energy use by a process unit: SECpr =

Epr P

(4)

In Equation (4), Epr—the total annual primary energy used by a process unit and P—the annual amount of products processed by the specific process unit.

Generally, energy use is related to weight units of an air-dried product, which is assumed to consist of 90% oven-dry pulp and 10% water content, even if the actual conditions vary in different environments [44]. The majority of the studies that have used SEC neither mentioned anything about the moisture content nor correction for the moisture content. The exception was a study at process

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level presented by Laurijssen et al. [10] that the SEC values for sections pre- and after drying were showed in units of absolute dry end product not in units of absolute dry product that was processed for comparing the two dryers.

Calculations of both of the variables “energy” and “product” are based on assumptions. Roughly speaking, the variable “product” relies on several assumptions. One of the assumptions regards the definition of “product”—is it product sold, i.e., all the produced products minus the products of inadequate quality that could not be sold, or is it all the products produced including the products of inadequate quality to be sold? For example, during the production of paper, e.g., when changing from the production of one paper grade to another or when a paper web breaks, some paper that was produced can be classified as internal waste due to inadequate quality [10]. The internal waste can be re-pulped, which could eliminate or minimize material waste. Nevertheless, the energy that was used for the production of paper of inadequate quality has been wasted [10]. Another example is assumptions originating from the challenges involved in dealing with partitioning of the products, i.e., joint production could cause difficulties in allocating how much energy was required for one specific product [12]. It is possible that this problem can be overcome by individual factories having access to e.g., continuous data, however such data is rarely—if ever—all available to external parties [12].

Furthermore, uncertainties in energy use because of variations in the analysed system boundaries can also be a challenge. For example, when benchmarking at process level, uncertainty can originate from a lack of clarity about whether only the energy used by the main equipment is included in the analyses. According to Laurijssen et al. [10], it is often the case that only the energy used by the main equipment is included and that used by auxiliary equipment is excluded, even though the auxiliary equipment (e.g., pumps, peripheral systems for water) also uses energy and is needed in production.

For example, >50% of the electricity used for drying pulp can be used for pumping [20]. Furthermore, according to Thollander et al. [45], the primary energy use is a function of the sum of the production processes and the product-dependent support processes’ energy use per product multiplied by the number of products, plus the support processes’ energy use. This ax + b function also tells us that the primary energy use is a function of the number of products, but also consists of a base load. This function differs tremendously between different types of companies, where for example a non-energy intensive mechanical engineering company may have support process-related base load energy use of 70–80% on an annual basis, while the same figure for an energy-intensive pulp mill might be few percent in comparison to the energy used, depending on production. Consequently, differences in how to set system boundaries can make the benchmarking of similar processes between different studies challenging. The studied system boundaries for calculating SEC varied substantially in the studies presented in Tables. Generally, the precision of the boundary description tended to increase the more detailed the intended benchmarking by using SEC such as in benchmarking at process level. Namely, detailed descriptions were common while studying SEC at process level, as in e.g., refs. [10] or [7], whereas for national and international comparison general description such as e.g., PPI in the country when studying SEC at national level without mentioning whether energy was used for not directly production-related processes such as support processes e.g., [6,46].

Regarding the total amount of energy, uncertainty comes from using energy from non-primary energy carriers, such as electricity. Since electricity is not a primary energy source, in order to calculate the total energy used, the amount of electricity needs to be multiplied by the primary energy factor (PEF). For example, the fixed PEF in Europe is 2.5 and emanates from the European Energy Efficiency Directive [47]. Using fixed PEF is convenient, but actual PEFs are directly related to country- and year-specific conditions which can deviate from the fixed PEF. This is due to the fact that PEFs tend to vary over time depending on the mix of energy carriers that were used to produce electricity specifically for individual countries. Using the fixed PEF has been criticized by e.g., [47]. PEF converts the usage of non-primary energy carriers such as electricity to the usage of primary energy carriers.

PEF is the ratio of primary energy use with the final energy use [48], and can be shown as in [45].

In Sweden, for example, the annual gross electricity, which is a non-primary energy carrier, production

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was calculated as the sum of annual electricity production from e.g., hydropower, nuclear power and imported electricity, minus exported electricity, and then divided by the net electricity used by all sectors in the country [6]. Calculations for the Swedish example were conducted using the Swedish Energy Agency’s data [49]. PEF results for Sweden are presented in Table 2, and show that the PEF for Sweden was lower than the fixed PEF in Europe (2.5) over the period from 2002 to 2015, i.e., 1.61–1.95 (Table 2).

Table 2. Primary energy factor (PEF) for Sweden over the period from 2002 to 2015.

Years

2002

2003

2004

2005

2006

2007

2008

2009

2010

2011

2012

2013

2014

2015

PEF

1.84

1.84

1.95

1.88

1.79

1.79

1.79

1.61

1.65

1.69

1.78

1.80

1.78

1.78

Hence, PEFs also differ among individual countries, e.g., according to Wilby et al. [47], the PEF is 3.4 for France, 1.4 for Norway and 2.9 for Poland. Differences in SEC between countries contribute to further uncertainties in regard to calculating SEC. If the exact assumptions and calculations are not presented when comparing studies from different countries, SECs need to be recalculated uniformly.

Even though it is possible that in some cases energy carriers with PEF of 1 can be used, the knowledge of how PEF affects SEC is important when comparing the SEC with that from studies with PEF of energy carriers not equal to 1. For instance, when evaluating changes in SEC over time that includes time with PEF for not all energy carriers being equal to 1.

For example, the average PEF for Sweden over the period 2002–2015 is 1.78, which makes the fixed PEF of 2.5 about 1.4 times higher. When the same data is used to calculate SEC for the total energy, the results show that the fixed PEF of 2.5 gives ~11% higher SEC for total energy for pulp mills and ~15% higher SEC for total energy for paper mills (Table 3).

Table 3. Specific individual energy carriers’ use and specific total energy use, calculated using PEF 1.78 and 2.5. Specific individual energy carriers’ use has been calculated from Farahani et al. [50].

Variables

Pulp Mill

Paper Mill

Steam use (GWh/kt) Electricity use (GWh/kt) Total energy, when PEF = 1.78 Total energy, when PEF = 2.5 Difference in SEC for total energy (%)

4.28 0.85 5.80 6.40 11.00

2.33 0.76 3.70 4.20 15.00

In summary, PEF differs, whereby a difference of 1.4 for one non-primary energy carrier can alone lead to ~11–15% difference in SEC. Therefore, it is recommended to describe what PEF have been used and how the PEF were calculated as well as to scrutinize what PEF in other studies were used for assuring the validity of the comparisons among SEC from different studies and for correctly evaluating sources for variation of SEC. 4.3. SEC in International Standards ISO 50001:2011 (standard on energy management systems—requirements with guidance for use [15]) specifies that an organization should identify the relevant energy performance indicators for monitoring and measuring its own energy performance, and that those indicators should be reviewed and compared to the appropriate energy baseline. Organizations shall establish, implement and maintain energy objectives and targets, as well as appropriate timeframes for their achievement, considering all the legal requirements, significant energy uses and opportunities for improving energy performance as identified in the energy review [15].

ISO 50006:2017 [17] provides instructions on how energy performance indicators (EnPIs) and energy baselines (EnBs) are established, used and maintained in the process of measuring energy

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performance within an organization, and how to determine whether the energy performance meets the targets set by the organization. Energy performance is understood as the “measurable results related to energy efficiency, energy use” [17]. When establishing EnPIs, different characteristics of the energy use, such as base load (e.g., fixed energy use) and variable loads, affected by production, occupancy, weather and other factors, should be taken into consideration. The energy performance can be influenced by different variables (weather conditions, production parameters, operating hours and operating parameters) and by static factors connected to changing business conditions such as market demand, sales and profitability. The relevant variables that can influence the energy performance should be defined, quantified and isolated in terms of significance (ranging from no influence or little influence to significant). The organization sets quantitative references, meaning EnBs for each EnPIs in order to compare EnPIs values over time and to quantify the changes in energy performance.

The results of energy performance can be expressed in SEC (e.g., kWh/unit), and when multiple forms of energy are used, conversion to a common unit of measure should be performed in such a way that the conversion process includes the total energy used and the losses. When comparing energy performance results, it is recommended that the EnPI and its corresponding EnBs are normalized by modifying the energy data so that the changes in relevant variables which affect energy performance are considered and the comparison is carried out under equivalent conditions [17].

According to SS-EN 16231:2012 (standard [9] on energy efficiency benchmarking methodology), when aiming to evaluate and compare performance between or within different entities, the performance data of comparable activities should be collected and analysed. This is basically the process of benchmarking, and different types exist, from internal benchmarking, which involves a comparison of energy performance at different locations within the same organization, to external benchmarking, which can be used to establish a series of EnPIs for either an installation or a product, within the same sector. Benchmarking boundaries should be clearly defined and limited to the process installation, facility, product, building or organization in such a way that the correction factors (e.g., weather conditions, product or service and associated technology, production level and quality of feed stock used) will be applied as little as possible. In energy efficiency benchmarking, the energy use of processes with the same output is assessed, and comparability of processes can be achieved in exceptional cases by the use of correction factors, i.e., well-defined adjustments of the SEC. In energy efficiency benchmarking, SEC is used as an indicator of energy use per (physical) unit of output, and the output can be a product, an activity or a service, e.g., GWh per kt of paper, GJ per tonne of steel, annual kWh per m2 , or kWh per full-time employee [9].

SS-EN 16212:2012 (standard [37] on energy efficiency and savings calculations, top-down and bottom-up methods) also defines SEC as the energy use per physical unit of output, and describes it at subsector level and relates the annual energy use to annual physical production. It connects the total energy use to the number of systems, in this case the equivalent of mean yearly energy use per system, e.g., GWh per kt of paper, GJ per tonne of steel, kWh per m2 of dwelling, kWh per refrigerator or L/100 km for vehicles. The change in SEC value over time is used as an energy efficiency indicator for top-down energy savings calculations, as it relates the energy use to a physical output or to the number of systems using energy.

When carrying out a top-down savings calculation, energy indicators will be selected and used.

The choice of energy savings indicators starts with the definition of energy savings, which is dependent on the types of drivers (economic, technical or behavioural factors) behind the changes in energy use.

When technical efficiency is assessed, SEC per physical unit is calculated. The steps for performing a general calculation of top-down energy savings are: definition of indicator types, calculation of indicator values and calculation of energy savings per indicator. Examples of SEC usage as indicators for these calculations are: (i) SEC at sub-sector level, which relates energy use to physical production (e.g., GWh/kt paper, MJ/tonne of steel, etc.) for a given period, usually a year; and (ii) SEC for energy using systems, which relates total energy use for specific systems to the number or size of systems.

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The annual energy use may be normalized, meaning that it can be corrected for yearly deviations from average climate that influence energy use and include heating and space cooling.

The value for SEC indicators is calculated using the formula below, where the normalized energy use (NEC) is divided by the driver quantity (DV) for the year t [37]: IND(t) =

NEC (t) DV (t)

(5)

where IND is indicator value, NEC is normalized energy use, DV is quantity for driver and t is year of evaluation.

The change in SEC indicator value is calculated as follows [37]: CIND = IND(t0 ) − IND(t)

(6)

where CIND is change in indicator value, IND is indicator value, t0 is base year and t is year of evaluation.

The energy savings per indicator are calculated as the change in indicator value multiplied by the driver quantity in the year of evaluation, as in the formula below [37]: ESPI = [IND (t0 ) − IND (t)] × DV(t)

(7)

where ESPI is energy savings per indicator, IND is indicator value, DV is quantity for driver, t0 is base year and t is year of evaluation.

When calculating energy savings for the industrial sector, SEC for energy-intensive industries is calculated as follows [37]: SEC =

Final energy use of the branch Production measured in physical units (e.g., kt)

(8)

As can be seen, SEC is presented and recommended as an energy performance indicator for energy efficiency and the formula presented is basically the same in all the reviewed standards. Practical guidance on the usage of SEC is presented, but more analysis on the challenges and usage of SEC is required. The calculations of SEC in the reviewed articles comply with the calculations recommended by the international standards. Additionally, the studies using SEC confirm that the usage of SEC also complies with the requirement to measure energy efficiency.

4.4. SEC Usage for Benchmarking In summary, according to the literature (e.g., [28,51]), the relationship between the amount of data and the precision of the identification for improvements can be as illustrated in Figure 1. In other words, the more disaggregated the level of benchmarking is, the more data is required [28]. For example, international benchmarking can be used to identify the potential for improved energy efficiency, but cannot specify where exactly the energy efficiency improvement measures can be found [51].

However, benchmarking at process level could identify such energy saving opportunities [51]. Notably, international benchmarking is generally challenging due to differences between the sectors, economic structure of the countries, etc. ([11,28]). In agreement, the reviewed studies confirmed that the more disaggregated the level such as e.g., process level, the more precision was required and given (e.g., [7,10,16]), whereas the more aggregated the level of benchmarking, the lower the precision (e.g., [6]). Some studies addressed one levels of benchmarking within their study (e.g., with the same study, e.g., [7,10,16]), whereas some of the other studies using SEC performed benchmarking at several levels within the same study (e.g., [52]).

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Figure 1. Trend in the relationship between the amount of data and the precision of identification for improvements according to literature (e.g., [28,51]).

Additionally, due to the uncertainties that can originate from the usage of different PEFs, more uncertainties when benchmarking at international level come from data on a highly aggregated level, such as when applying the total annual energy used without further explanations and specifications (see e.g., Table 1). For example, SEC can be higher or lower for an entire PPI depending on the dominant type of the mill, i.e., pulp mills, paper mills, integrated pulp and paper mills, etc. The types of products that the various mills produce can also affect SEC. The decision on whether to use only direct process data or to include other data, e.g., energy used for waste water treatment, support processes, etc., also influences SEC. Examples of SEC are presented in Table 4.

Table 4. Examples of SEC for the pulp and paper industry (PPI). “n.s.” means that the PEF was not specified in the references and was therefore recalculated as presented in Section 3.

Total Energy (GWh/kt)

PEF

Region

Reference

Year

Source for SEC

PPI PPI PPI (processes) PPI PPI

16.70 9.33 14.20 11.10

n.s. n.s. n.s. n.s.

[53] [54] [53] [53]

1987 1994 2002 2009

From literature From literature From literature From literature

PPI

6.40

n.s.

India USA India India Best available technologies (BAT)

Energy Used by

[53]

2016

From literature Calculated from official data

3.86

~1.7

Sweden

[6]

average 2006–2016

Pulp mill

4.23

~1.7

Sweden

[6]

average 2006–2015

Calculated from official data

Paper mills Paper industry

6.23

n.s.

[46]

1981

From literature

Paper mill

3.90

2.50

USA Organization for Economic Co-operation and Development (OECD)

[55]

2001

From literature

Paper mill (Average)

4.39

~1.7

Sweden

[6]

average 2006–2016

Calculated from official data

2.95

~1.7

Sweden

[6]

average 2006–2017

Calculated from official data

PPI (average) Pulp mills

Integrated mills Integrated mills

When comparing the results from other studies, it is not always clear what a certain SEC covers de facto depending on the choice of wording. For example, “pulping” is used to describe the process used “to free fibres in wood from lignin that binds these fibres together, and then to suspend the fibres in water into a slurry suitable for paper making” ([56], p. 14). For example, the SEC of “pulping chemical” is 1.48 GWh/kt in [54] and probably refers only to the pulping process according to the definition above

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by Kramer et al. [56]. However, in some references “pulping” is more likely to be used to describe pulp making including all processes that were used to produce pulp, judging by the SEC values. Namely, the SECs for BAT for “chemical pulping” amount to 4.85 GWh/kt and 4.84 GWh/kt in [57], and are in line with SEC values for “chemical pulp total”, 4.47–5.10 GWh/kt, in [7] and “chemical wood pulp”, 4.53 GWh/kt, in [8] (Tables A1 and A2 in Appendix A).

Examples of SEC for various paper grades are presented in Table A3 in Appendix A, and SEC for various processes during paper production is presented in Table A4 in Appendix A. SEC for paper grades under the same or similar names, e.g., newsprint, seems to vary more than could be accounted for by using different PEFs. For example, SEC for newsprint varies from 1.44 to 2.55 GWh/kt, making the comparison between SEC from different studies challenging.

5. Analysis and Proposed Improvements When Using SEC Despite the frequent use of SEC when benchmarking and working towards improving energy efficiency, clear and detailed descriptions of the assumptions that the SEC calculations are based on seem to be lacking in both scientific literature and international standards. Therefore, based on the review of scientific publications and standards addressing and using SEC, the following important improvements are proposed to improve the reliability and comparability of SEC:

• • •

•

Define system boundaries. For example, describe whether energy use by auxiliary systems, wastewater treatment facilities, support systems, in situ transport, etc. were included.

Describe all the assumptions and calculations for calculating the amount of energy used.

For example, how the PEFs were calculated and what data was used.

Define the products and assumptions for calculating the amounts of products. For example, are the products everything that was produced or only the products that were sold? Present assumptions and calculations for calculating amounts of products when partitioning of products was present.

When comparing with SECs from other studies, beware of the possible effects due to the differences in assumptions, calculations and other relevant issues, e.g., environmental effects.

6. Conclusions The importance of being able to monitor the progress of industrial energy efficiency cannot be understated. With the aim of critically analysing SEC in relation to industrial energy efficiency, some conclusions could be drawn from this study:

• • • •

• • •

SEC is affected by several factors (Figure 2).

SEC is of greater use if longitudinal benchmarking, i.e., the same company, sector or country, over time, is undertaken.

If using SEC for benchmarking between companies, sectors, or countries, extreme caution is required in order to benchmark correctly.

The reviewed standards in this paper provide useful general guidance on the use of SEC as an indicator for energy efficiency, but do not provide a reader with sufficient details of the full range of challenges when using SEC. Hence, more support is needed in this respect, to support both researchers and industry practitioners. Since there is a gap in both research and international standards in the usage and challenges of SEC, a plan for further use of SEC together with monitoring activities is needed.

The difference in the primary energy factor (PEF) can influence SEC calculations significantly.

SEC is a more optimal e-KPI within the same study, when all deployed SECs are calculated in the same way, and with the same underlying assumptions.

We suggest that specific exergy consumption with the abbreviation SEC would be a more correct term than specific energy consumption. Alternatively, specific energy use could be used.

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•

•

•

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Prior to the use of SECs from other studies, it is recommended that the factors affecting the production of the products, calculations and assumptions on which these calculations were based should be scrutinized critically to ensure the reliability of the comparisons.

SEC is a convenient and easy-to-use energy efficiency indicator with the potential for use in various benchmarking applications, provided that it is calculated with adequate assumptions and calculations to ensure its reliability.

Further quantitative analyses are recommended on SEC from various studies for studying the underlying tendencies and relationships among the factors affecting SEC, e.g., the time trends, extent of studies, levels of benchmarking, etc.

We recommend to be clear about the assumptions and calculations when calculating SEC and applying SEC from other studies for enabling evaluation whether the possible difference in SEC is not just caused by the differences in the underlying assumptions when calculating SEC alone.

Specifically, it is recommended to consider:

Origin, availability and quality of information and data that was used for calculating SEC. That system boundaries are as precise as possible, e.g., energy used by the main equipment and/or auxiliary equipment used in production and/or parts of it.

The conversion of non-primary energy carriers to primary energy carriers, e.g., the PEF used.

The calculation of energy use and the number of products for individual products in cases when partitioning of products is present.

Whether sold products or produced products used for the calculations.

Other factors that may influence SEC such as specifications of equipment, e.g., age of equipment, specifications of production, e.g., production rate, and environmental conditions.

Figure 2. Examples of factors affecting the numbers for energy used and products, and therefore SEC. Author Contributions: All the parts of the manuscript were discussed among all the authors. A.L. was the main author and wrote all the parts except the one about SEC in international energy management systems, which was mainly written by M.A. Funding: This research was funded by the Swedish Energy Agency, research project number 40537-1, the Swedish Environmental Protection Agency, Carbonstruct research project, project number 802-0082-17, and the Division of Energy Systems at the Department of Management and Engineering, Linköping University.

Acknowledgments: Authors thank the anonymous reviewers for the comments.

Conflicts of Interest: The authors declare no conflict of interest.

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Appendix A Table A1. Examples of SEC for various pulps listed alphabetically. BAT—Best available technology.

BAU—Business as usual. OECD—Countries that are members of the Organisation for Economic Co-operation and Development.

Total Energy (GWh/kt)

PEF

Region

Reference

Year

Chemical pulp, total

5.10

2.50

Germany

[7]

2011

Chemical pulp, total

5.10

2.50

Germany

[7]

2007

Chemical pulp, total

5.10

2.50

Germany

[7]

2020

Chemical pulp, total

4.89

2.50

Germany

[7]

2035

Chemical pulp, total

5.10

2.50

Germany

[7]

2020

Chemical pulp, total

4.89

2.50

Germany

[7]

2035

Chemical pulp, total

5.03

2.50

Germany

[7]

2020

Chemical pulp, total

4.47

2.50

Germany

[7]

2035

Chemical pulping Chemical Pulping

4.85 4.84

2.50 2.50

[57] [57]

2001–2004 2001–2004

Chemical wood pulp

4.53

2.50

BAT BAT OECD: Australia, Sweden, the Netherlands, France, the UK, the USA, Germany, Japan

Calculated using data in literature Calculated using data in literature Modelling BAU diffusion Modelling BAU diffusion Modelling cost-effective diffusion Modelling cost-effective diffusion Modelling technical diffusion Modelling technical diffusion From literature From literature

[8]

1990

BAT from literature

4.72 8.01

2.50 2.50

Canada Canada

[55] [55]

2003 2001

From literature From literature

Energy Used by

Source for SEC

Chemical pulp mill

Kraft mill pulp Kraft mill (actual) Kraft mills (actual) Kraft mills (modern mill—BAT) Pulp by kraft process

4.28

2.50

Canada

[55]

2001

From literature

4.03

n.s.

Canada

[58]

2000

Calculated

Mechanical pulp Mechanical pulp, total

4.94

2.50

Germany

[7]

2011

Mechanical pulp, total

4.93

2.50

Germany

[7]

2007

Mechanical pulp, total

4.76

2.50

Germany

[7]

2020

Mechanical pulp, total

4.53

2.50

Germany

[7]

2035

Mechanical pulp, total

4.64

2.50

Germany

[7]

2020

Mechanical pulp, total

4.36

2.50

Germany

[7]

2035

Mechanical pulp, total

4.08

2.50

Germany

[7]

2020

Mechanical pulp, total

3.18

2.50

Germany

[7]

2035

Mechanical pulping

5.21

2.50

[57]

2001–2004

Mechanical wood pulp

3.11

2.50

[8]

1990

BAT from literature

5.21

2.50

BAT OECD: Australia, Sweden, the Netherlands, France, the UK, the USA, Germany, Japan BAT

From literature Base year, calculated using data in literature Modelling BAU diffusion Modelling BAU diffusion Modelling cost-effective diffusion Modelling cost-effective diffusion Modelling technical diffusion Modelling technical diffusion From literature

[57]

2001–2004

4.67

2.50

Germany

[7]

2011

From literature Calculated using data in literature

3.25

n.s.

n.s.

[59]

1999–2006

Mechanical pulping Sum, mechanical pulp (GWP) Thermomechanical pulping (TMP)

From literature

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Table A1. Cont.

Total Energy (GWh/kt)

PEF

Other fibre pulp

3.33

2.50

Other wood pulp

3.33

2.50

Pulp by alcohol extraction

5.53

n.s.

Energy Used by

Region

Reference

Year

Source for SEC

[8]

1990

BAT from literature

[8]

1990

BAT from literature

[58]

2000

Other pulp OECD: Australia, Sweden, the Netherlands, France, the UK, the USA, Germany, Japan OECD: Australia, Sweden, the Netherlands, France, the UK, the USA, Germany, Japan Canada

Pulping

7.60

n.s.

Taiwan

[52]

2007

Pulping

8.06

n.s.

Taiwan

[52]

2008

Pulping

8.46

n.s.

Taiwan

[52]

2009

Pulping

8.45

n.s.

Taiwan

[52]

2010

Pulping

7.82

n.s.

Taiwan

[52]

2011

Pulping Pulping Pulp

8.06 7.22 1.67

n.s. n.s. n.s.

India India China

[52] [52] [5]

2004 2007 1985–2010

0.79

2.50

Germany

[7]

2011

0.76

2.50

Germany

[7]

2007

0.76

2.50

Germany

[7]

2020

0.76

2.50

Germany

[7]

2035

RCF pulp (recycled cellulose fibre), total

0.76

2.50

Germany

[7]

2020

RCF pulp (recycled cellulose fibre), total

0.69

2.50

Germany

[7]

2035

0.76

2.50

Germany

[7]

2020

0.69

2.50

Germany

[7]

2035

Sum, RCF pulp

0.80

2.50

Germany

[7]

2011

Recycled fibre input

1.08

2.50

Waste paper pulp De-inked waste paper pulp De-inked waste paper pulp

0.39 1.68 1.68

Pulp from recycled materials RCF pulp (recycled cellulose fibre), total RCF pulp (recycled cellulose fibre), total RCF pulp (recycled cellulose fibre), total RCF pulp (recycled cellulose fibre), total

RCF pulp (recycled cellulose fibre), total RCF pulp (recycled cellulose fibre), total

Calculated Calculated using self-collected data Calculated using self-collected data Calculated using self-collected data Calculated using self-collected data Calculated using self-collected data From literature From literature Calculated

Calculated using data in literature Base year, calculated using data in literature Modelling BAU diffusion Modelling BAU diffusion Modelling cost-effective diffusion Modelling cost-effective diffusion Modelling technical diffusion Modelling technical diffusion Calculated using data in literature

[8]

1990

BAT from literature

2.50

OECD: Australia, Sweden, the Netherlands, France, the UK, the USA, Germany, Japan BAT

[57]

2001–2004

From literature

2.50

BAT

[57]

2001–2004

From literature

2.50

OECD

[55]

2001–2004

From literature

Table A2. Examples of SEC for various processes during pulp production, listed alphabetically.

Energy Used by

Total Energy (GWh/kt)

PEF

Region

Reference

Year

Source for SEC

0.60 0.25 0.08 1.44 0.25 0.20 4.50 −0.38

2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50

USA Germany Germany USA Germany Germany Germany Germany

[54] [7] [7] [54] [7] [7] [7] [7]

1994 2011 2011 1994 2011 2011 2011 2011

From literature From literature From literature From literature From literature From literature From literature From literature

Pulp mills’ processes Bleaching Bleaching, mechanical pulp (GWP) Bleaching, RCF pulp Chemical recovery Concentration and dispersion, RCF pulp De-inking (floatation), RCF pulp Grinding, mechanical pulp (GWP) Heat recovery, mechanical pulp (GWP)

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Table A2. Cont.

Energy Used by

Total Energy (GWh/kt)

PEF

Region

Reference

Year

Source for SEC

Others, RCF pulp Pulp drying Pulping chemical Pulping mechanical Pulping other Pulping wastepaper

0.05 0.15 1.48 0.58 0.08 0.00

2.50 2.50 2.50 2.50 2.50 2.50

Germany USA USA USA USA USA

[7] [54] [54] [54] [54] [54]

2011 1994 1994 1994 1994 1994

Pulping, RCF pulp

0.10

2.50

Germany

[7]

2011

Screening, RCF pulp

0.13

2.50

Germany

[7]

2011

Washing, mechanical pulp (GWP)

0.13

2.50

Germany

[7]

2011

Wood handling, mechanical pulp (GWP)

0.17

2.50

Germany

[7]

2011

Wood preparation

0.28

2.50

USA

[54]

1994

From literature From literature From literature From literature From literature From literature Calculated using data in literature Calculated using data in literature Calculated using data in literature Calculated using data in literature From literature

Table A3. Examples of SEC for various paper grades, listed alphabetically. BAT—Best available technology. OECD—Countries that are members of the Organisation for Economic Co-operation and Development. LWC—Light-weight coated. SC—Supercalendered.

Energy Used by

Total Energy (GWh/kt)

PEF

Paper mills: individual paper grades Boxboard 1.38 2.50 Brown kraftliner 2.92 2.50 Coated fine paper 4.47 2.50 Coated mechanical 1.56 2.50 Coated papers 3.08 2.50 Coated papers 3.08 2.50 Coated papers 3.08 2.50 Coated wood-free 1.94 2.50 Containerboard 1.70 2.50 Folding board 3.43 2.50 Folding boxboard 3.43 2.50 Folding boxboard 3.94 2.50 Folding boxboard 3.43 2.50 Household and 3.93 2.50 sanitary paper Household and 3.93 2.50 sanitary paper Household and 3.93 2.50 sanitary paper Kraft papers 2.13 2.50 LWC magazine paper 3.53 2.50 Newsprint 2.55 2.50

Region

Reference

Year

Source for SEC

OECD Finland Finland OECD BAT BAT OECD OECD OECD OECD BAT Finland BAT

[55] [60] [60] [55] [57] [57] [55] [55] [55] [55] [57] [60] [57]

2001 1993 1993 2001 2001–2004 2001–2004 2001–2004 2001 2001 2001–2004 2001–2004 1993 2001–2004

From literature From literature From literature From literature From literature From literature From literature From literature From literature From literature From literature From literature From literature

BAT

[57]

2001–2004

From literature

OECD

[55]

2001–2004

From literature

BAT

[57]

2001–2004

From literature

[55] [60] [57]

2001 1993 2001–2004

From literature From literature From literature

[8]

1990

BAT from literature

[16] [55]

1997 2001

From literature From literature

Newsprint

1.67

2.50

Newsprint Newsprint Newsprint mill (modern—BAT) Newsprint mills (actual) Newsprint, SC magazine paper Office paper

2.42 1.44

n.s.

2.50

OECD Finland BAT OECD: Australia, Sweden, the Netherlands, France, the UK, the USA, Germany, Japan The Netherlands OECD

6.30

2.50

Canada

[55]

2001

BAT from literature

7.47

2.50

Canada

[55]

2001

From literature

3.03

2.50

Finland

[60]

1993

From literature

3.69

2.50

[60]

1993

From literature

Other paper

2.92

2.50

[8]

1990

BAT from literature

Other paper Packaging

2.64 3.36

n.s. n.s.

[16] [16]

1997 1997

From literature From literature

Packaging paper

2.44

2.50

Finland OECD: Australia, Sweden, the Netherlands, France, the UK, the USA, Germany, Japan The Netherlands The Netherlands OECD: Australia, Sweden, the Netherlands, France, the UK, the USA, Germany, Japan

[8]

1990

BAT from literature

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Table A3. Cont.

Energy Used by

Total Energy (GWh/kt)

PEF

Region

Reference

Year

Paper

3.68

n.s.

Taiwan

[52]

2007

Paper

3.89

n.s.

Taiwan

[52]

2008

Paper

4.03

n.s.

Taiwan

[52]

2009

Paper

4.01

n.s.

Taiwan

[52]

2010

Paper

4.11

n.s.

Taiwan

[52]

2011

Paper and paperboard Paper and paperboard Paper and paperboard not specified elsewhere Paper and paperboard not specified elsewhere Paper and paperboard not specified elsewhere

10.17 3.17

n.s. n.s.

China China

[5] [5]

1985 2010

Calculated using self-collected data Calculated using self-collected data Calculated using self-collected data Calculated using self-collected data Calculated using self-collected data Calculated Calculated

3.36

2.50

BAT

[57]

2001–2004

From literature

3.36

2.50

BAT

[57]

2001–2004

From literature

3.36

2.50

OECD

[55]

2001–2004

From literature

Paper, total

2.85

2.50

Germany

[7]

2011

Paper, total

2.85

2.50

Germany

[7]

2007

Paper, total

2.79

2.50

Germany

[7]

2020

Paper, total

2.64

2.50

Germany

[7]

2035

Paper, total

2.58

2.50

Germany

[7]

2020

Paper, total

2.46

2.50

Germany

[7]

2035

Paper, total

2.58

2.50

Germany

[7]

2020

Paper, total

2.35

2.50

Germany

[7]

2035

Paperboard

2.46

n.s.

Taiwan

[52]

2007

Paperboard

2.35

n.s.

Taiwan

[52]

2008

Paperboard

2.39

n.s.

Taiwan

[52]

2009

Paperboard

2.38

n.s.

Taiwan

[52]

2010

Paperboard

2.10

n.s.

Taiwan

[52]

2011

2.71

2.50

OECD

[55]

2001–2004

From literature

4.28

n.s.

[16]

1997

From literature

3.33

2.50

The Netherlands OECD: Australia, Sweden, the Netherlands, France, the UK, the USA, Germany, Japan

[8]

1990

BAT from literature

2.71

2.50

BAT

[57]

2001–2004

From literature

Printing and writing paper Printing/writing Printing/writing paper

Source for SEC

Calculated using data in literature Calculated using data in literature Modelling BAU diffusion Modelling BAU diffusion Modelling cost-effective diffusion Modelling cost-effective diffusion Modelling technical diffusion Modelling technical diffusion Calculated using self-collected data Calculated using self-collected data Calculated using self-collected data Calculated using self-collected data Calculated using self-collected data

Printing and writing paper Printing and writing paper Sanitary

2.71

2.50

BAT

[57]

2001–2004

From literature

4.69

n.s.

[16]

1997

From literature

Sanitary paper

3.06

2.50

[8]

1990

BAT from literature

Tissue paper Tissue and speciality Uncoated mechanical Uncoated wood-free

4.44 4.38 1.69 1.44

2.50 2.50 2.50 2.50

The Netherlands OECD: Australia, Sweden, the Netherlands, France, the UK, the USA, Germany, Japan Finland OECD OECD OECD

[60] [55] [55] [55]

1993 2001 2001 2001

From literature From literature From literature From literature

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Table A3. Cont.

Energy Used by Wrapping and packaging paper and board Wrapping and packaging paper and board Wrapping and packaging paper and board

Total Energy (GWh/kt)

PEF

Region

Reference

Year

Source for SEC

2.45

2.50

BAT

[57]

2001–2004

From literature

2.45

2.50

OECD

[55]

2001–2004

From literature

2.45

2.50

BAT

[57]

2001–2004

From literature

Table A4. Examples of SEC for various processes during pulp production, listed alphabetically.

BAT—Best available technology. OECD—Countries that are members of the Organisation for Economic Co-operation and Development.

Total Energy (GWh/kt)

PEF

Region

Reference

Year

Board, after drying

0.08

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Board, drying sections

1.33

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Board, forming and press section

0.36

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Board, other processes—paper machine

0.08

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Board, other stock preparation

0.28

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Board, pre-drying

1.25

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Board, stock preparation

0.19

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Board, total processes—paper machine

2.08

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Board, wire and press

0.42

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Coating

0.01

2.50

[57]

2001

From literature

Coating

0.01

2.50

Typical, country not specified OECD

[55]

2001

Dry-end, coating and finishing

0.25

2.50

Germany

[7]

2011

Dry-end, dryer section

1.29

2.50

Germany

[7]

2011

Dry-end, press section

0.25

2.50

Germany

[7]

2011

Graphic, after drying

0.72

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Graphic, coating/sizing/laminating

0.06

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Graphic, drying sections

2.11

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Graphic, forming and press section

0.42

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

From literature Assumptions and calculations based on literature Assumptions and calculations based on literature Assumptions and calculations based on literature Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases

Energy Used by

Source for SEC

Paper mills: processes Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases

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Table A4. Cont.

Energy Used by

Total Energy (GWh/kt)

PEF

Region

Reference

Year

Graphic, other processes paper machine

0.19

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Graphic, other stock preparation

0.78

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Graphic, pre-drying

1.31

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Graphic, stock preparation

0.64

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Graphic, total processes—paper machine

3.47

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Graphic, wire and press

0.42

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Other

0.42

2.50

USA

[54]

1994

Other, after drying

0.14

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

0.03

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Other, de-inking

0.47

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Other, de-inking

0.17

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Other, dispersion

0.33

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Other, dispersion

0.11

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Other, drying sections

1.47

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Other, forming and press section

0.36

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Other, other processes paper machine

0.11

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Other, other stock preparation

0.31

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Other, pre-drying

1.36

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Other, stock preparation

0.22

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Other, total processes—paper machine

2.61

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Other, wire and press

0.42

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Others, other processes (effluents, compressed air)

0.31

2.50

Germany

[7]

2011

Paper machine

3.10

2.50

[57]

2001

From literature

Paper machine Paper machines in newsprint mills (GJ/ad tonne)

3.10

2.50

Typical, country not specified OECD

[55]

2001

From literature

3.36

3.50

Canada

[55]

2003

From literature

Other, coating/sizing/laminating

Source for SEC Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases From literature Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Assumptions and calculations based on literature

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Table A4. Cont.

Energy Used by

Total Energy (GWh/kt)

PEF

Region

Reference

Year

Paper production

3.13

2.50

Netherlands

[16]

1997

Papermaking

4.30

2.50

USA

[54]

1994

Stock preparation

0.51

2.50

Stock preparation Stock preparation, pulper Stock preparation, refiner Stock preparation, screening Sum, processes for paper production

0.51

2.50

Typical, country not specified OECD

0.03

2.50

0.33

Source for SEC Assumptions and calculations based on literature Assumptions and calculations based on literature

[57]

2001

From literature

[55]

2001

Germany

[7]

2011

2.50

Germany

[7]

2011

0.08

2.50

Germany

[7]

2011

2.85

2.50

Germany

[7]

2011

Tissue, de-inking

0.28

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Tissue, de-inking

0.22

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Tissue, dispersion

0.44

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Tissue, dispersion

0.42

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Tissue, dispersion and de-inking

0.72

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Tissue, drying sections

1.94

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Tissue, forming and press section

0.44

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Tissue, other processes—paper machine

0.08

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Tissue, other stock preparation

0.92

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Tissue, pre-drying

1.92

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Tissue, stock preparation

0.64

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Tissue, total processes—paper machine

4.08

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

Tissue, wire and press

0.53

2.4 for electricity and 1.1 for heat

Netherlands

[10]

2011

From literature Calculated using data in literature Calculated using data in literature Calculated using data in literature Calculated using data in literature Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases Measured, calculated and from official databases

Total paper mill

3.90

2.50

Typical, country not specified

[57]

2001

Wet-end, forming section

0.08

2.50

Germany

[7]

2011

Wet-end, headbox

0.25

2.50

Germany

[7]

2011

7.93

n.s.

China

[61]

2015

7.78

n.s.

BAT EU

[61]

2015

5.57

n.s.

BAT USA

[61]

2015

Paper mill (coated paperboard production) Paper mill (coated paperboard production) Paper mill (coated paperboard production)

From literature Calculated using data in literature Calculated using data in literature Calculated from collected data Calculated from collected data Calculated from collected data

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Energy 2014, 73, 771–779. [CrossRef] Swing Gustafsson, M.; Gustafsson, M.; Myhren, J.A.; Dotzauer, E. Primary energy use in buildings in a Swedish perspective. Energy Build. 2016, 130, 202–209. [CrossRef] SEA Energy Use in Numbers 2017, [Energiläget i siffror 2017, in Swedish]. Available online: http://www. energimyndigheten.se/nyhetsarkiv/2017/nu-finns-energilaget-i-siffror-2017/ (accessed on 2 June 2017).

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Farahani, S.; Worrell, E.; Bryntse, G. CO2-free paper? Resour. Conserv. Recycl. 2004, 42, 317–336. [CrossRef] Francis, D.W.; Browne, T.C. Method for benchmarking energy use in pulp and paper operations. In Proceedings of the 2004 TAPPI Technical Conference, Indianapolis, IN, USA, 29 August–2 September 2004; p. 10.

Chan, D.Y.L.; Huang, C.F.; Lin, W.C.; Hong, G.B. Energy efficiency benchmarking of energy-intensive industries in Taiwan. Energy Convers. Manag. 2014, 77, 216–220. [CrossRef] Bajpai, P. Pulp and Paper Industry: Energy Conservation; Elsevier: Amsterdam, The Netherlands, 2016.

Worrell, E.; Martin, N.; Anglani, N.; Einstein, D.; Khrushch, M.; Price, L. Opportunities to Improve Energy Efficiency in the U.S. Pulp and Paper Industry; Lawrence Berkeley National Lab: Berkeley, CA, USA, 2001; p. 13.

IEA (International Energy Agency). Tracking Industrial Energy Efficiency and CO2 Emissions; IEA: Paris, France, 2007. [CrossRef] Kramer, K.J.; Masanet, E.; Xu, T.; Worrell, E. Energy Efficiency Improvement and Cost Saving Opportunities for the Corn Wet Milling Industry; An ENERGY STAR® Guide for Energy and Plant Managers; Lawrence Berkeley National Lab: Berkeley, CA, USA, 2009.

IEA. Energy Technology Transitions for Industry. Strategies for the Next Industrial; IEA: Paris, France, 2009; ISBN 9789264068582.

Morris, D.R.; Steward, F.R.; Gilmore, C.A. Comparative analysis of the consumption of energy of two wood pulping processes. Energy Convers. Manag. 2000, 41, 1557–1568. [CrossRef] Walter, K.; Paulsson, M.; Wackerberg, E. Energy efficient refining of black spruce TMP by using acid hydrogen peroxide: Part 2. Washing, chelating and bleaching studies. Nord. Pulp Pap. Res. J. 2009, 24, 266–272. [CrossRef] Komppa, A. Paper and energy: A Finnish view. In Energy Efficiency in Process Technology; Elsevier Applied Science: London, UK, 1993; pp. 101–110.

Zhang, Y.; Hong, M.; Li, J.; Chen, X.; Zeng, Z. Benchmarking Analysis of Energy Efficiency Indicators in Paper Mill. Bioresources 2016, 11, 9723–9740. [CrossRef] © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

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Volume 6, Number 1, 2020

Application of soda-AQ pulping to agricultural waste (okra stalks) from Sudan 1

2

3

3

Safaa Hassan Omer , Tarig Osman Khider , Osman Taha Elzaki , Salaheldin Dafalla Mohieldin and 3 Suhair Kamal Shomeina .

Abelmoschus esculentus okra as whole stalks was examined for its suitability for pulp and paper production.

It’s, fiber dimensions, morphological and chemical characteristics were reported. The pulping trials with soda- Anthraquinone (AQ,) at different chemical charges. Application of 21% as NaOH with 0.1% AQ gave good results in degree of delignification, mechanical properties. Utilization of okra pulps and blender is recommended due to good pulp properties. Evaluation of general characteristics of okra stalks in terms of fiber dimensions morphological indices, chemical components, Soda-AQ cooking and to study their suitability for paper production. Okra Fiber dimension evaluation done after maceration with a mixture of 30% hydrogen peroxide and acetic acid (1:1) for core and bark parts separately and was carried out under microscope staining with aqueous safranin. The Soda-AQ cooks at different active alkali levels were calculated as NaOH on oven dry raw material. The fibers from okra stalks studied (core and bark) were in the range of hardwood fibers, with short fiber length, especially the core with more or less moderate walls, narrow lumen and fiber width. The fiber width of bark was medium –narrow with medium wall thickness. The ash content was rather high whereas the silica content was comparatively high The hot water extractives from okra stalks was (4.1%), cold water (0.4) ethanol/ cyclohexane (1.1), ethanol extractives (1.2%) and 1% NaOH (27.6%) were rather high. The cellulose (Kurschner-Hoffer) was (48.5%) The lignin content was (15.3%) which was relatively moderate. The use of 0.1% AQ enhanced the delignification in the three trials applied. The screened yield increase with increase of chemical dose applied while the rejects decrease.

When 21% NaOH was applied, the screened yield was 32.2% with negligible amount of rejects, however with lower alkali charge 18% the screened yield was decreased to 28% with very low rejects 1.5%. on the other hand rejects were increased to 7% when 15% NaOH was applied with very low screened yield 19%.The pulps produced from okra soda-AQ are suitable for production of printing and writing papers and it is advisable to use them in blending due to good papermaking properties.

Contact information: 1: University of Bahri, College of Natural Resources and Environmental Studies, Khartoum, Sudan.

2: Industries Department, College of Applied and Industrial Sciences, University of Bahri Sudan, P.O. Box 1606, Khartoum, Sudan.

3: Cellulose Chemistry and Technology Research Unit, National Centre of Research, Khartoum, Sudan.

Omer et al. BMC Chemical Engineering (2019) 1:6 https://doi.org/10.1186/s42480-019-0005-9 This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

The Paper Industry Technical Association (PITA) is an independent organisation which operates for the general benefit of its members – both individual and corporate – dedicated to promoting and improving the technical and scientific knowledge of those working in the UK pulp and paper industry. Formed in 1960, it serves the Industry, both manufacturers and suppliers, by providing a forum for members to meet and network; it organises visits, conferences and training seminars that cover all aspects of papermaking science. It also publishes the prestigious journal Paper Technology International and the PITA Annual Review, both sent free to members, and a range of other technical publications which include conference proceedings and the acclaimed Essential Guide to Aqueous Coating.

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Article 10 – Agri-Pulping

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How to Lead Through a Crisis When faced with a crisis, most leaders are forced to think and behave in ways that feel unfamiliar. Whether it’s a technological, financial, natural, or health crisis — at work or in the community — crises demand that leaders take an emergency response plan and adapt it as new evidence and factors present themselves.

All the while, effective leaders are able to remain calm and maintain a sense of perspective. According to Gene Klann, author of our book Crisis Leadership, “During a crisis, your goal is to reduce loss and keep things operating as normal as possible.”

Especially as organizational leaders face the current coronavirus (COVID-19) pandemic and associated disruptions in the global economy, Klann recommends 5 actions to prepare and respond.

Also: Relationships Matter During a Crisis

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Maintaining Perspective in a Crisis

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www.ccl.org

The Paper Industry Technical Association (PITA) is an independent organisation which operates for the general benefit of its members – both individual and corporate – dedicated to promoting and improving the technical and scientific knowledge of those working in the UK pulp and paper industry. Formed in 1960, it serves the Industry, both manufacturers and suppliers, by providing a forum for members to meet and network; it organises visits, conferences and training seminars that cover all aspects of papermaking science. It also publishes the prestigious journal Paper Technology International and the PITA Annual Review, both sent free to members, and a range of other technical publications which include conference proceedings and the acclaimed Essential Guide to Aqueous Coating.

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Article 11 – Leading in a Crisis

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Volume 6, Number 1, 2020

FIVE WAYS TO LEAD AND ADAPT THROUGH A CRISIS 1. Seek credible information.

As a leader, it’s your responsibility to determine the most reliable, up-to-date information from trustworthy news sources. “Avoid getting information only from social media, and be wary of any news organizations that have a political, financial, or activist agenda,” says Klann. “Their information may be biased and, to varying degrees, inaccurate.”

In the current case of the coronavirus, Klann recommends consulting state and local health services, the World Health Organization — which provides rolling updates — and the Centres for Disease Control and Prevention, where you can find advice on how to prepare and take action, whether you’re at home or affiliated with K-12 schools and childcare programs, universities, mass gatherings, etc.

2. Use appropriate communication channels.

Once essential information is gathered, it should be disseminated to the entire organization by every means possible. Transparency is key. “Information is the oil that greases an organization and keeps it running smoothly,” Klann says. “This is especially true during a crisis.”

Information is powerful because it: x x x x

reduces emotional distress caused by the unknown, diminishes fear, provides tactical guidance, and demonstrates to employees that their leaders are concerned, involved, knowledgeable, and on top of the situation.

How to communicate? Face-to-face first, whether in person or through virtual channels. With a plethora of tools for hosting and personalizing virtual meetings, quarantines don’t have to stand in the way of your group coming together face-to-face.

“Key information should be handled with the 3 Rs: review, repeat, reinforce,” Klann adds. “If information is shared only once, it cannot be assumed everyone has received it — or if they did, that they understand it.”

Repeating and reinforcing information on a daily basis and via multiple delivery methods helps it to sink in and be retained.

“Remember, when information regarding what is happening is scarce or non-existent, people revert to gossip and rumours and also tend to ‘MSU’ it. That is: Make Stuff Up,” Klann says. “Invariably, what they make up will be worse than reality, no matter how bad reality is.”

3. Explain what your organization is doing about the crisis.

During a crisis, time is compressed. The initial onset of a crisis presents immense pressure to act — and act quickly. Sometimes you have to begin tackling a problem before you have a solid grasp of what’s happening.

If you are in charge, take charge. Be proactive; take initiative. Do something even if it might be wrong; paralysis or over analysing is riskier. As you make decisions and take action, communicate those actions truthfully and honestly.

“With the coronavirus, you might choose to reduce air travel, ask more people to work from home, place hand sanitizer in strategic places within the facilities, encourage those with the sniffles or a cough to stay home, and frequently clean high-trafficked areas or objects and surfaces,” Klann says. As your response changes, keep employees updated with the 3 Rs. Remember that everyone observing or living through a crisis views it through a unique lens. For example, a paramedic will understand only that a hospital is overloaded; a hospital administrator will only know that the generator isn’t working. Keep in mind that no one will have a complete, accurate picture of what’s going on.

Watch our webinar, Leadership Agility in Times of Change and Crisis, and learn to increase leadership agility in order to make strategic decisions and ignite commitment to move your organization forward.

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Article 11 – Leading in a Crisis

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

4. Be present, visible, and available.

During a crisis, leaders should be accessible. Because it’s not always possible to walk around your facility and talk to colleagues in person, let employees know how they can best reach you with status updates and questions. “Particularly during a crisis, employees have a need to hear from their leaders frequently. When leaders appear calm, concerned, knowledgeable, and in charge, workers feel encouraged and are more likely to have confidence that things are under control and will be fine,” says Klann.

Understand that organizational protocol needs to account for flexible leadership ranks during an emergency.

Whoever is in charge is whoever is there. An entire operation cannot be hamstrung because bureaucracy didn’t account for a key player being unavailable when an emergency struck.

5. Dedicate organizational resources for future crises.

As any crisis transitions from its urgent phase, the time pressure will ease, as will the need for split-second decisions. At that point, the plan must evolve into a more complex system that looks at recovery and getting things back to normal — whatever the new normal looks like.

If a similar emergency unfolds in the future, will you be prepared? “All leaders will admit that crisis planning — for example, having a Crisis Action Plan and setting aside resources for a crisis — are important,” says Klann. “But experience shows that key resources are seldom placed in reserve for contingencies. And if they are, they’re usually inadequate.”

While improvisation cannot be planned, thinking and team-building exercises can be built into a training program that prepares everyone for a similar, future crisis.

RELATIONSHIPS MATTER DURING A CRISIS During a crisis, leaders who have built a personal, relational, and cultural foundation can then focus on the immediacy of the moment. According to Klann, effective crisis leaders often do the following.

Four Ways to Stay in the Present: x

Face your emotions.

Recognizing and managing the emotions of the situation — others’ as well as your own — can help with individual and group resiliency, getting people to safety, and then back to normal (or a new normal). People with an imbalanced emotional state don’t process well. It is important to do anything you can to reduce the emotional stress on people while “doing the job.” x

Show respect.

Treat people with sincere consideration and genuine concern. Show it by paying attention, listening, and responding to what people are telling you, as well as considering what is not being said. x

Make connections.

Draw on a sense of loyalty, courage, morality, or other principles that tie your crisis response to what is important to people. x

Be positive.

A leader’s attitude is contagious. Leaders are dealers in hope. Even in extreme crisis, an upbeat, can-do attitude keeps people going.

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Article 11 – Leading in a Crisis

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

MAINTAINING PERSPECTIVE IN A CRISIS During a crisis, leaders are often focused on the emotional turmoil of their direct reports and others in the organization, but it’s equally important for leaders to take care of themselves.

“A crisis can exert a high impact on human needs, emotions, and behaviours,” says Klann. “We may not be conscious of this, but our behaviours send messages to others about our own underlying needs and emotions.”

Whatever leadership role you play, you need to be aware of your own emotional turmoil, its effect on your behaviour, and its influence on your leadership abilities.

Take these actions to keep the perspective you need to bring your people and your organization through a crisis.

Four Ways to Stay Cool in a Crisis: x

Think “today.”

Take the crisis one day at a time. x

Focus on the positive.

Avoid negative people, negative thoughts, and negative talk. Constantly think positive thoughts and tell yourself that you can do it. x

Get grounded.

Take 5-minute private breaks. Practice relaxation techniques, such as meditation and deep breathing. Don’t neglect spiritual exercises and activities as they fit your individual beliefs. x

Prioritize and focus.

Keep meetings short or “on the hoof,” where everyone stands. Be more assertive. Say “no” more often. Be more conscious about managing your time and priorities. Concentrate on only major issues. Skip secondary tasks.

Finally, Klann advises leaders in times of crisis to remember the big picture. “Concentrate on the greater vision you have of yourself, both personally and professionally. Think about where you will be and what you will be doing a year from now,” he says. “Stop and realize that you are alive and that much good will come out of the crisis.”

By paying attention to your own emotions, needs, and behaviours, you will be better prepared to handle the human dimensions of the crisis. As a result, you will be more capable of containing the crisis, regaining control, minimizing damage, and effectively preventing, defusing, and reducing the duration of an extremely difficult leadership situation.

For more tips on leading in times of turmoil, access the full text of Klann’s book, Crisis Leadership: Using Military Lessons, Organizational Experiences, and the Power of Influence to Lessen the Impact of Chaos on the People You Lead.

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Article 11 – Leading in a Crisis

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Volume 6, Number 1, 2020

Eight Ways to Keep Remote Employees Motivated During Crisis As telecommuting is becoming more and more popular within the workplace, it is important that businesses continue to address the needs of all of their employees – including those who work from home. Employee engagement is of extreme importance in every company, we know that much. But how do we continue to drive engagement throughout our remote workforce during this time of crisis?

Though it may seem nearly impossible, the answer to that question is actually quite simple. Use these 8 strategies to motivate and engage remote employees during tough times. www.lumapps.com

The Paper Industry Technical Association (PITA) is an independent organisation which operates for the general benefit of its members – both individual and corporate – dedicated to promoting and improving the technical and scientific knowledge of those working in the UK pulp and paper industry. Formed in 1960, it serves the Industry, both manufacturers and suppliers, by providing a forum for members to meet and network; it organises visits, conferences and training seminars that cover all aspects of papermaking science. It also publishes the prestigious journal Paper Technology International and the PITA Annual Review, both sent free to members, and a range of other technical publications which include conference proceedings and the acclaimed Essential Guide to Aqueous Coating.

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Article 12 – Motivating in a Crisis

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

1. Encourage Frequent Communication When employees feel disconnected or out of the loop, they often lose motivation. Remote employees are often forgotten or left out of certain discussions, leading them to feel abandoned and unmotivated. So it’s extremely important, especially in times of crisis, to drive strong internal communication with your remote teammates.

Make it a priority to schedule weekly or even daily video-call meetings with your team members, invest in a strong communication platform, and establish an “open-door” policy with your employees. Thorough, frequent communication between offsite employees leads to higher productivity and employee engagement.

2. Establish Clear Goals and Expectations Oftentimes, when remote employees are not producing enough high-quality work, this stems from a lack of clear goals and expectations. When managing remote teams, it’s easy to let expectations, guidelines, and goals slip through the cracks as it becomes more challenging to maintain constant communication with your employees.

When this happens, telecommuters are forced to guess what their manager needs from them, leading to incorrect or non-relevant work and, ultimately, disengaged employees. Therefore, managers must make it a priority to establish clear goals and expectations with all remote employees and communicate these guidelines in a highly-detailed message or video call.

3. Offer Your Employees Opportunities for Growth According to Achievers’ 2020 Engagement & Retention Report, “43% of employees are looking for or would consider leaving their company because of career advancement”. Offering growth opportunities to your remote employees, even during times of crisis, will help drive employee motivation and job satisfaction.

These growth opportunities don’t necessarily have to be promotions, raises, or title changes. They can be something as simple as offering “lunch and learns”, encouraging and even rewarding participation in virtual conferences. You can also spend 15 minutes during quarterly/monthly reviews mapping out employees’ career paths either within or outside of the company. Offering growth opportunities helps remote workers feel important, engaged, and generally happy. As a result, they are more likely to continue producing high-quality work.

4. Recognize Employees’ Efforts Employees who feel underappreciated or undervalued are highly likely to disengage from their work, which often leads to poor quality of work. Ensuring that your remote employees feel appreciated and publicly recognized for the effort they put in is crucial when it comes to employee engagement. Something as simple as posting a “Thank You Note” or “Giving Kudos” to your employees on your social and collaborative intranet platform can go a long way. When employees receive recognition for their hard work, they are more likely to remain satisfied and engaged in their current role.

5. Provide Tips and Training to Help Remote Employees Manage Their Time It’s easy to get distracted when working from the comfort of your home, especially if your entire family is in the house with you. Employees who are not used to telecommuting, often struggle with time management when working at home. To boost engagement and ensure that these employees are managing their time properly, be sure to provide your remote team with tips and training options on time management. A great way to do this would be to ask one of your regularly remote employees to make a post containing tips and tricks for time management on your communication platform. You can also include training videos or one-onone training, coaching employees on how to manage time effectively while working remotely.

6. Establish and Emphasize Culture When shifting to a remote workforce amid crisis, company culture tends to shift or, in some cases, disappear entirely. Maintaining strong company culture is vital if you want to keep remote teams engaged during tough times. Continue to build trust with your teammates by offering consistent, transparent communication.

It is also important to continue team-building activities like happy hours, team lunch, coffee breaks, and team games in order to cultivate culture. Doing this with remote employees calls for creativity and openmindedness, but all of these get-togethers can be done via video call. This drives collaboration and enthusiasm across the company while we are all working remotely.

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Article 12 – Motivating in a Crisis

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

7. Offer Mentorship and Training Opportunities Having a mentor in the workplace can significantly affect employee engagement. It is important for employees to have a coworker who they can go to when times are tough and when things are going great.

Mentors help their mentees set goals, work through difficult situations, share professional knowledge, and usually act as a confidence-booster for their mentees during stressful times. Remote employees have less face to face interactions with coworkers which can lead to feelings of isolation. Having a mentor, someone you trust and are comfortable with, helps to combat those feelings of isolation when telecommuting.

8. Utilize a Strong Internal Communication Platform While email is effective for most business functions, it is an inadequate tool for internal communication in a remote work environment. Having a tool that allows employees to share stories, pictures, videos, documents, etc. in one place makes all the difference when it comes to engagement within remote teams. Employee engagement surveys can also be a great way to constantly improve your organization’s communication.

These surveys allow employees to communicate their needs to management while remaining anonymous.

Utilizing a communication platform that allows managers and employees to communicate and share information in real time helps remote teams feel as though they are all together everyday. Communication is key, especially in times of crisis, and having a social and collaborative environment where teammates can share experiences and knowledge takes communication to a whole new level and further drives remote employee motivation.

Many companies already utilize these strategies to generate employee engagement, but it is vital that we keep them at the forefront of our business plan while we navigate these bumpy waters and work remotely.

Keep in mind that employee motivation cannot be forced and doesn’t happen overnight. However, if you continually utilize these engagement strategies and remain true to your company’s vision and mission, you will likely drive remote employee motivation during times of crisis.

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Article 12 – Motivating in a Crisis

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Volume 6, Number 1, 2020

Driving Issues From fuel efficiency and basic maintenance to UK driving laws, car and van drivers have a lot to remember whenever they get on the road. Below are seven recent posts received in the PITA e-post bag with tips and information, most of which are equally applicable outside of the UK. 1. Six Money Save Hacks for Drivers

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2. Six Pieces of Van Parking Etiquette

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3. Six things that need to be filled up in a vehicle

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4. Three tips to prevent rust on your vehicle

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5. Vehicle safety warning amid lock down

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6. Six reasons why a clean van means better business

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7. Nine Hygiene Tips for Drivers

Page 8

www.LeaseVan.co.uk

The Paper Industry Technical Association (PITA) is an independent organisation which operates for the general benefit of its members – both individual and corporate – dedicated to promoting and improving the technical and scientific knowledge of those working in the UK pulp and paper industry. Formed in 1960, it serves the Industry, both manufacturers and suppliers, by providing a forum for members to meet and network; it organises visits, conferences and training seminars that cover all aspects of papermaking science. It also publishes the prestigious journal Paper Technology International and the PITA Annual Review, both sent free to members, and a range of other technical publications which include conference proceedings and the acclaimed Essential Guide to Aqueous Coating.

Page 1 of 8

Article 13 – Driving Issues

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

SIX MONEY SAVE HACKS FOR DRIVERS Drivers have been offered six money saving hacks to help keep costs down when it comes to owning a vehicle.

Motoring experts from LeaseVan.co.uk are encouraging drivers to wash their own vehicles and ensure liquids are topped up to help prevent expensive one-off costs.

Whilst drivers cannot change much about the prices of fuel and tax, they should shop around when it comes to renewing their insurance.

Driving economically will also reduce the amount of fuel the vehicle uses, so that you don’t have to fill up quite as often.

A spokesperson for LeaseVan.co.uk said: “Running your own vehicle can be an expensive affair with costs such as fuel, insurance and tax to consider – and this is before any potential one-off costs such as fixing a dent or scrape. Trying to keep costs down and saving money by washing the vehicle yourself, for example, can help alleviate the strain on your wallet.”

These are LeaseVan.co.uk’s money-saving tips for drivers: 1. Wash it yourself Washing your vehicle yourself and not going to a car wash can help save you lots of money in the long run. It also means that you can tailor the job to the vehicle’s needs, ensuring abrasive materials and liquids aren’t used to keep paint jobs looking fresh and shiny.

2. Keep up to date When a warning light comes on it is easy to just ignore it, but that is probably making the problem worse. By having the problem sorted when it first appears, although it will cost you, you may be putting off an even more expensive issue which is further down the line.

3. Top up liquids By keeping all the liquids in the vehicle topped up, such as oil and water, it means that everything will run smoothly and hopefully have no problems. When oils run low this is when parts of the engine break and costs can soon run up.

4. Fuel One of the biggest costs involved with running a vehicle is keeping it topped up with fuel. Finding petrol stations that are cheaper could be the way to go, but ensure you’ve factored in the cost of driving to and from the station. Also ensuring you’re driving economically can have a big effect. Try and drive as smoothly as possible without any sudden accelerating or breaking.

5. Car insurance Legally required, and important to have, this is another expense that comes with running a car. You can usually haggle a little bit with certain providers, and make sure you shop around before you renew the insurance with your current provider. It is normally cheaper to pay in one go instead of in monthly instalments, if your bank balance allows.

6. Think about parking Although it might be quicker to park right at the front of a car park, it’s also increasing the risk of your vehicle getting dented. Even parking your vehicle under trees which are likely to drop sap can increase the risk of rusting.

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Article 13 – Driving Issues

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

SIX PIECES OF VAN PARKING ETIQUETTE Van drivers have been urged to steer clear of parking too close to junctions and directly in front of property windows, to aid road safety and avoid annoying neighbours.

It can often be a challenge to park vans considerately as a novice because they are generally longer, wider, taller and heavier than cars. A typical commercial vehicle usually lacks back windows and a rear view mirror too, increasing parking difficulty. So driving specialists have revealed some things to bear in mind, which could also help fellow UK road users avoid any unnecessary accidents.

Tim Alcock from LeaseVan.co.uk said: “Our customers often request driving advice when leasing their first van. Because of the size and awkwardness of vans compared to cars, one of the most frequently asked questions is how should I park it? Our advice is to be extra-vigilant, given the reduced visibility and increased size compared to cars. One of the most important things, too, is to be as considerate as possible – try your best not to annoy or obstruct other road users.”

Here is the LeaseVan.co.uk guide to help inexperienced van drivers park their vehicles without annoying local residents and the general public: 1. Park as far away from junctions as possible Parking your van right on a road corner or opposite a junction can cause problems and potential danger for fellow road users. It could significantly obstruct visibility, blocking drivers view of oncoming traffic when attempting to turn, and even reduce the available space for others vehicles to manoeuvre in, if the location determines your van is parked on-street rather than in a designated bay.

2. Try to stay off the pavement If circumstances mean you’ve got no choice but to park partially on a pavement, try to leave as much room as possible, especially for prams, wheelchairs, the elderly and children – rather than forcing pedestrians to cross over. It’s always best to seek an available, larger parking space nearby before putting your van on a pavement though, to avoid annoying locals.

3. Be sensitive to homeowners light and view Well-mannered van drivers won’t park their bulky vehicles directly in front of a property’s windows, particularly if they’re going to be parked in that same spot for a large proportion of the day. This can be problematic as it can stop natural light getting in to a home and block the residents views of the outside world, be it some great British scenery or even curtain-twitching and people-watching.

4. Anticipate and avoid narrowing roads Drivers should, wherever possible, steer clear of parking vans on stretches of road where doing so would make it avoidably tight or impossible for other vehicles to pass in both directions at the same time. If your load is light, consider leaving your vehicle further away. If you can’t, try to plan for a quiet time of day, and be quick.

Van owners also must try to find a more appropriate, alternative space further down the street or around the corner, if parking in their initial location might obstruct access for emergency services.

5. Think twice about getting in the way at car parks At supermarkets, multi-storey car parks and out of town retail locations, van drivers shouldn’t park straddling two bays, horizontally across multiple spaces or attempt to squeeze in to a tight spot right on top of the store.

Instead, find a space that’s specifically designed for larger vehicles or in a quieter area further away from the shop or facility’s front doors. If you need to load bulky or heavy items, you can always pull your van around to the entrance briefly, after you’ve finished shopping.

6. Be considerate of neighbours if you’re on the job Tradespeople conducting domestic or local work should utilise properties’ driveways or park as close as possible to the house their working on, rather than unnecessarily taking any neighbours’ usual, coveted on street parking spots in busy areas.

Just as when driving a car, it’s important to make sure you aren’t blocking any required access, such as to neighbours’ driveways, when parking your van. If building materials make any mess on the pavement or surroundings as you’re loading or unloading, make sure to clear it up.

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Article 13 – Driving Issues

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

DON’T FORGET THE OIL! SIX THINGS THAT NEED TO BE FILLED UP IN A VEHICLE Drivers have been reminded of six things which should be kept topped up in their car and van – to avoid unsafe driving conditions and a hefty repair bill.

Vehicle experts from LeaseCar.uk have warned drivers that forgetting to fill up gas, oil and antifreeze could leave them with a hefty bill. Problems can be caused if liquids such as oil aren’t kept at the required level, as this is what the vehicle needs to lubricate its mechanics. Various liquids are essential to ensure systems within the vehicles are able to run smoothly without causing an issue.

A spokesperson for LeaseCar.uk said: “You can’t really forget about filling up petrol, otherwise your vehicle wouldn’t run at all! But there are a few other things which should be regularly checked and topped up if necessary, which are sometimes easier to forget. It’s often a case of out of sight, out of mind, but these are standard checks that won’t take long to do, so it’s important to keep on top of them.”

1. Fuel Whether this be petrol, diesel, or even electricity – fuel is needed to ensure your vehicle can start. Its perhaps the easiest thing to remember to fill up as your car will let you know when it’s running low, but you should be careful not to take risks and always have plenty of fuel left in your tank for any planned journey.

2. Washer fluid There’s nothing more annoying than having a dirty windscreen and realising you can’t clean it because your washer fluid has run out – but it can be quite dangerous too. This should be regularly filled up to ensure your vehicle is to a safe standard and able to drive.

3. Oil You can check how much oil your car has, and whether it needs filling up, using the dipstick under the bonnet. Pull it out and wipe it clean, then dip it into the oil tank, and see where it comes to between the ‘minimum’ and ‘maximum’ lines. Oil is needed to ensure the engine runs smoothly, and without it could cause serious – and costly – problems.

4. Air Your tyre pressure can change regularly, but it’s important to check regularly to make sure your vehicle is safe to drive. The correct pressure for your tyres will be detailed in the vehicle’s manual. Ensure you check your tyres before a long journey, but they should also be checked and filled – if needed – every few weeks.

5. Air freshener People that spend a lot of time in their vehicles will want to make sure it’s clean, and an air freshener can help keep pungent smells at bay. Some tradespeople can spend nearly all day in their van, so topping up or replacing air fresheners when they run out will ensure your vehicle smells nice and fresh, and is a pleasant environment to be in.

6. Anti-freeze Antifreeze should be topped up regularly with the liquid used for your engine’s cooling system – especially at this time of year when cold snaps are always imminent. If the water was allowed to freeze it could expand and break the radiator, which would leave you with a hefty bill to cover.

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Article 13 – Driving Issues

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

THREE TIPS TO PREVENT RUST ON YOUR VEHICLE Weather-beaten British drivers have been offered advice on how to protect their vehicles from rust and water damage.

Motoring experts from LeaseVan.co.uk have revealed three top tips on how to reduce the chance of rust affecting the metal on cars and vans.

Rust is the orange-brown discolouration that builds up when metal objects are exposed to oxygen and moisture. A form of iron oxide, it occurs when iron combines with the oxygen in the air, causing the metal to corrode. Rust can affect iron and its alloys, including steel, and as well as looking unattractive, if untreated, rust can completely decimate an entire structure.

Tim Alcock from LeaseVan.co.uk said: “Rust causes metal to expand, which can place great stress on the structure as a whole, weakening the metal and making it brittle and flaky. Unfortunately, prolonged exposure to outdoor conditions will always increase the risk of rust, especially if its rainy or humid – but there are ways you can prevent it from happening. Regular maintenance and upkeep are key, but you can also apply antirust products to protect your car’s body paint.”

1. Wash your vehicle regularly If you want to stop rust from starting or spreading, then you have to make a habit of washing your vehicle on a regular basis – however, you should always thoroughly dry all moist or wet areas afterwards as any moisture left on metallic surfaces can cause rusting.

Dirt and dust cannot directly cause corrosion, but they can rub against the protective paint on your car and with constant friction, the paint can wear off, inviting the development of corrosion.

Similarly, bird droppings may seem like benign organic matter, but the compounds present in these animal wastes can also cause a chemical reaction on the clear coat of the car. The same is true with automotive liquids like brake fluid and fuel. If any of these fluids spill onto metal parts of the car, then there’s a chance that corrosion can take place, so washing your car or van regularly will prevent this from happening.

2. Apply anti-rust products All modern vehicles undergo extensive application of rust-protection technologies before they roll out of the assembly, and some manufacturers apply several layers of corrosion-resistant automotive paints on the car’s body – however, exposure to the elements can still eat away at the paint. These same compounds can interact with the anti-rust treatment, so it’s advisable to apply a rust prevention spray.

Before applying this product to your vehicle, make sure to clean, wash and dry it off first. It makes no sense to apply rust proofing car protection on surfaces that are covered in dirt or dust!

3. Address early signs of corrosion If you spot any sign of corrosion on your car, you must treat it straight away, as leaving it will just allow it to get worse. There are rust repair kits available on the market, but these only work on minor rust.

If you don’t want to use these kits or if the rust is more severe, then you can use sandpaper. Start with a 180-grit sandpaper, then 320-grit, before finishing it off with 400-grit. This will help remove the rust from the surface while smoothing it out.

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Article 13 – Driving Issues

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

VEHICLE SAFETY WARNING AMID LOCK DOWN Motorists have been warned to ensure their cars and vans stay roadworthy after a lengthy period of non-use.

Motoring experts from LeaseVan.co.uk have told drivers to park their vehicles under the cover of a garage wherever possible, or to invest in a car cover and put their vehicles under wraps during the expected period of inactivity.

They also warned motorists to ensure tyre pressures and fluids are maintained at the correct levels while their vehicles are out of action.

Cars and vans can become unroadworthy if left idle on the street for lengthy spells, so the experts said it was essential to maintain and check them again before use to ensure they are safe to drive.

Tim Alcock from LeaseVan.co.uk said: “Most drivers will use their cars daily and will remember to fill up relevant fluids as they go, but it’s just as important to do so if you know you won’t be using the vehicle for a while. If you plan to leave your car unused for a considerable period, you can follow these steps to keep the vehicle in good, running condition.”

1. Park indoors or use a car cover Where possible, you should leave your car in a garage as it’ll be safer and cleaner. If you don’t have this option – which most drivers won’t – instead invest in a quality cover. Make sure you buy one that’s been designed for your car model or type. However, avoid using a cover if you’re parking the car in a garage, as this will ensure any moisture that is left inside the vehicle will evaporate faster.

2. Clean the interiors People tend to leave various types of rubbish in their cars – wrappers, old water bottles and so on. If left for long periods, it could attract rodents that can damage floor mats, seat covers and even wiring. So, clean the interior thoroughly and spray a little air freshener.

3. Fill up on fuel One of the biggest problems of leaving a car unused is rusting on the inside of the fuel tank. The best way to avoid this is to fill the car to the brim with quality petrol.

4. Protect paint job A car’s paintwork can be damaged if a vehicle is parked outdoors, even with a car cover protecting it, due to the dust, grim and moisture. To prevent damage, clean the exterior thoroughly.

5. Inflate the tyres If your car is going to be sitting for a longer period of time than usual, tyres might slowly lose a significant amount of pressure. For this reason, it’s a good idea to inflate your tyres to the recommended air pressure, but do not exceed the maximum. Then repeat this process the next time you use the vehicle.

6. Top off fluids Before you leave your car dormant for an extended period of time, top off your vehicle’s fluids – brake fluid, engine coolant, power steering fluid, transmission fluid, antifreeze and windshield wiper fluid. Then, go for a quick, short drive, as this will help circulate the fluids, including the fuel stabiliser.

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Article 13 – Driving Issues

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

SIX REASONS WHY A CLEAN VAN MEANS BETTER BUSINESS Tradespeople are being warned that failing to keep their vans clean and tidy could negatively impact their business.

Motoring experts from LeaseVan.co.uk have reminded van drivers that many customers will choose not to use a certain business if their company vehicles aren’t up to standard.

Visible fast food wrappers, dirty signage and dents and scrapes all project a bad image of the company – but these can be easily avoided.

And dirt might not impact just the business, but also workers’ health if they spend a lot of time in the vehicle.

Tim Alcock of LeaseVan.co.uk said: “You wouldn’t turn up to work in dirty clothes, so why would you turn up with a dirty van? The whole reason vans are branded is so that potential customers can easily spot the details, and if these are all dirty and unreadable it defeats the purpose. A van should be seen as a moving advertisement. Tidying out your rubbish at the end of each day and giving it a regular clean won’t take long but will work wonders for finding new customers.”

These are LeaseVan.co.uk’s six reasons for keeping a van neat and tidy: 1. For Safety If dirt and grime begins to build up on windows and wing mirrors it can compromise visibility and therefore safety. Also, having very muddy tyres can have an effect on efficient breaking and generally safety.

2. To ensure branding and contact details are visible Treat your van like a business card, hundreds of people a day may see the van, and it has all the information on it for them to become new customers. If they cannot see the details then it results in a lot of missed opportunities, which could have been easily avoided by a quick wash.

3. To enhance your image You never get the chance to make another first impression. Having a clean and tidy van shows dedication to the company, and also shows it’s something you’re proud of. A dirty van may suggest a poor standard of work, exactly what you’re not wanting to convey.

4. To reduce maintenance costs Dirt and grime, if not regularly cleaned, can cause much more serious problems to your van, such as making it rust quicker than normal – again not a good look. Regular washing will also mean you’re having to pay close attention to the van meaning any problems will be caught early on, instead of being left to get worse.

5. For a better work ethic We’ve all heard the saying ‘tidy desk, tidy mind’ – the same can be said for your van. If it’s clean and clutter free it’s likely you will also feel like this helping you to de-stress in what is your office.

6. For health Germ and bacteria can quickly build up, and when you spend a lot of time in your van it’s not a great place to be. It’s important to clean the interior of the van too – places such as the steering wheel and gear stick which you touch more than anything else.

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Article 13 – Driving Issues

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

NINE HYGIENE TIPS FOR DRIVERS UK motorists have been offered guidance for minimising health risks and maintaining good hygiene levels when driving cars and vans. Motoring experts from LeaseVan.co.uk have released nine pieces of advice to help drivers maintain good health and personal hygiene while in their vehicles. From what to keep stashed in the glovebox to the steps vehicle owners should take to minimise the spread of germs, following the guidance could help Brits who spend a lot of time behind the wheel steer clear of conditions in their car or van that could harm their health.

A spokesperson for LeaseVan.co.uk said: “There’s plenty of advice out there for keeping your home or workplace hygienic. But there isn’t for the place where many Brits probably spend the third largest amount of time – their vehicles. Drivers who are on the roads daily for significant periods will be familiar with the need to stay both active and well rested. Wise motorists typically factor in time for stretching their legs and napping when going on particularly long journeys. But stiff joints could be the least of your worries if you don’t take sufficient steps to prevent potentially harmful bacteria building up and spreading in your vehicle.

“Catching an avoidable cold or worse could seriously impact drivers work and family lives. So we’ve put together a series of nine top tips to help motorists steer clear of possible illness.”

Here is the LeaseVan.co.uk advice: 1. Keep alcohol gel in the vehicle Keeping an antibacterial hand sanitiser gel in the glove box of your vehicle, often made from alcohol, allows you to maintain proper hand hygiene and clean any dirt from your fingers before they touch anything.

2. Wipe surfaces regularly To stop bacteria building up, to be touched or breathed in, surfaces including the steering wheel, gear stick, door handles and dashboard should be wiped clean frequently – especially if the vehicle is shared between multiple drivers.

3. Wear gloves when filling up Most petrol stations provide free disposable globes, which drivers can take advantage of to prevent any grime from getting under their finger nails when refuelling their vehicles.

4. Hoover the footwells often Just like a doormat at home, the footwell of a car will have all sorts of dirt and bacteria walked into it, which will grow and could prove problematic if not cleaned away regularly. Don’t simply mask damp or mouldy carpet smells with an air freshener and hope the problem goes away.

5. Allow fresh air in Breathing in too much recycled air doesn’t help your respiratory system, so drivers on long journeys should wind their windows down occasionally to allow fresh air to circulate through the vehicle – even if it’s a bit chilly outside.

6. Try to minimise travel with unwell people The confined environment of a car or van can be a prime location for catching illnesses off friends and family, so drivers should usually try to steer clear of offering lifts to anyone they know is under the weather.

7. Catch coughs and sneezes, but not in your hands Drivers should cough and sneeze into a disposable tissue, their inner elbow or inside the collar of their shirt, rather than into their hands or completely unprotected – both of which can spread harmful bacteria. It’s never recommended to take a hand off the steering wheel for longer than necessary or if road conditions mean doing so could be dangerous though.

8. Carry mouthwash and floss Keeping a small bottle of mouthwash and a roll of floss in the vehicle’s glovebox can allow you to keep on top of vital oral hygiene, particularly after eating, even when a toothbrush and sink is inaccessible.

9. Eat well even during long road trips Your body needs fuel to fight illnesses and other health issues, so you should keep a stash of daily vitamins on hand if you spend a lot of time in your vehicle. While on long road journeys, stay well rested, properly hydrated and try to stick to regular and healthy meals that give you all the nutrients you need, rather than simply snacking on fatty and sugary foods.

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Article 13 – Driving Issues

PAPERmaking!

O THE PUBLISHERS U S S OF O PAPER TECHNOLOGY INTERNATIONAL FROM

Volume 6, Number 1, 2020

Thirteen etiquette conference calls

tips

for

video

N.F. Mendoza Due to the coronavirus, virtual meetings are now standard for employees working from home. Follow these video conferencing tips on staying connected and professional. www.techrepublic.com

The Paper Industry Technical Association (PITA) is an independent organisation which operates for the general benefit of its members – both individual and corporate – dedicated to promoting and improving the technical and scientific knowledge of those working in the UK pulp and paper industry. Formed in 1960, it serves the Industry, both manufacturers and suppliers, by providing a forum for members to meet and network; it organises visits, conferences and training seminars that cover all aspects of papermaking science. It also publishes the prestigious journal Paper Technology International and the PITA Annual Review, both sent free to members, and a range of other technical publications which include conference proceedings and the acclaimed Essential Guide to Aqueous Coating.

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Article 14 – Video Conferencing Etiquette

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

Video or audio, Zoom, Skype, or Google Meet--being a part of virtual meetings has become the norm, as companies have sent employees to work from home for the foreseeable future, or at least until there's confidence COVID-19 is under control.

Especially for those more familiar with in-person meetings, remote conference calls can be a challenge: There are often participants who struggle with the technology or their at-home bandwidth. Once "in" the meeting, people also often talk over each other, which is even more critical not to do, given issues of buffering, delays, and speaker clarity.

Meetings are a must "Love them or hate them, meetings are a part of almost every job, whether you're working remotely or working in an office," said Kathy Gardner, senior director of PR & media, FlexJobs.

"In a remote workplace, finding daily opportunities to still see your coworkers, helps us stay connected, especially those that you may not work with on a daily basis," said Armen Vartanian, vice president, global workplace services, Okta. "That aspect of the office environment is lost when everyone is remote." Vartanian said he conducts a daily 15-minute meeting to simply stay engaged.

Anyone who has sat through the tedium of daily meetings that involve roll calls, and awkward lulls can appreciate what Robert Love, CTO for Q-CTRL, a facilitator in development of quantum computers, said, "Don't have meetings for meetings' sake, have a facilitator, have an agenda and stick to it."

TOP TIPS FOR CONFERENCE CALL ETIQUETTE FlexJobs' focus is on the flexible work environment, and the company recently released a list of the top 13 tips for remote conference etiquette. Other business experts also weigh in, too.

1. Always have an agenda There's nothing more irritating (and frustrating and not productive) than a meeting in which everyone languidly checks in, and then the person who scheduled the meeting has no plan. Don't schedule a meeting if you don't have an agenda. "Agendas don't have to be long, involved, or even particularly detailed," FlexJob suggested. "A brief outline of what topics the meeting will cover is usually good enough."

By providing staff with an agenda, attendees know what to expect, can guesstimate how long it will run, and, if there is an element of participation, will give them an opportunity to prepare talking points. "If you know you have people coming from other meetings, then maybe start the meeting five minutes after the start time," said James McQuiggan, security awareness advocate, KnowBe4, who added, regarding agendas, "Include it in the meeting notice. Also, have it on a slide that is shared and readily available."

"As a leader on a call, it can be challenging to bring a remote team to focus and communicate effectively, so it's important for the leader to assign ownership across the team and help facilitate the conversation amongst the group," Okta's Vartanian said. "Creating hand-offs in the conversation can make sure everyone on the call feels engaged and understands key takeaways, and helps you avoid those awkward transitions or lulls."

2. Report your absence "Skip the small talk about weather," said Dominik Zane, CEO, Around video-chat software. "Being on time also minimizes the need for everyone else to make small talk while waiting for late joiners."

If you are not going to be at the meeting, or if you're going to be late, tell the person leading the meeting (or a trusted team member) as soon as you know. Call, email, or text. Conference calls are often held up waiting for specific attendees. Sometimes conference calls are held up because everyone is waiting "a few more minutes."

Being seen on video is an important element of conference call etiquette, "It's important for participants to keep their video on as much as possible, particularly in the current context," said Andrey Khusid, CEO of Miro, a white-boarding platform. "Video adds a human touch to meetings, which can combat isolation and strengthen team relationships. And it can help the meeting facilitator identify whose attention is wandering, so they can bring them back into the conversation."

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Article 14 â&#x20AC;&#x201C; Video Conferencing Etiquette

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

3. Prioritize updates Some staff are larger than others, and conference call meeting size has a bit more relevance than in-person meetings. If you're in an office with a tight quartet of people, you're likely to know each other, and what you need to do. Someone will likely keep things "on track," and it's likely to be efficient. However, when you have, for example, more than eight people, it's critical to "prioritize what you will and won't talk about," FlexJobs said.

Set time constraints and stick to them. This allows each person to talk about what is relevant and can cap the overall length of the meeting.

An important thing to remember, the report noted, is make sure that what's going to be discussed is relevant to at least three people in the meeting. Otherwise, send an email on the topic or conduct a smaller meeting.

"Being mindful of time is key to conference call etiquette."

4. Test equipment Don't wait until a couple minutes before a meeting to sign on.

On cell phones: Make sure you have: x A strong signal x No interference On a computer x Use a wired connection rather than Wi-Fi x Make sure the computer camera works (or is uncovered) x Make sure the speakers work x Make sure the microphone works Even if it says you're connected to the platform, make sure you actually are. Test your video and audio before the meeting starts (hence the tip to sign on early enough to do this).

Allow even more time in case there is something to download beforehand or in case you have an unexpected update.

"Call quality is a theme, and when you're dealing with a 100% remote situation, where all participants are on the call, this is exacerbated," Q-CTRL's Love said. "My number one tip would be to invest in a headset.

People have no problem dealing with substandard video, but substandard audio is a deal breaker and can render a call useless."

5. No sneaking out This is not a third-grade recorder performance, or for some, church. Don't sneak out. In a virtual meeting, there's enough flexibility for you to attend part of it and then jump off. However, it's important you tell your supervisor or the person leading the meeting.

In some platforms, you can just sign off, and no one will know; in others, your face or name disappears from the shared screen. And if your company uses the former, don't cut out just because you can. If you have a conflicting appointment, tell everyone at the start of the meeting or send an email (that you know has been read) ahead of time.

If you have something else scheduled, you're more likely to be called on to share updates and add feedback early on. You don't want to be called on or asked a question and then appear to have suddenly vanished.

Transparency, people.

6. Be prepared It's bad conference etiquette to be called on and be unprepared. It's also a missed opportunity. Just because it's on a platform/phone doesn't mean your meeting prep is any different. Have notes on your phone next to you, and bookmark anything you need for reference. Clear your desktop of unnecessary files.

If it's a check-in or update meeting, discuss your current project and any recent accomplishment (it should go without saying, but don't brag or pat yourself on the back too much). Be clear and concise, and if you're uncomfortable with speaking to a group, practice beforehand. Let attendees know that if they have questions, you'll answer them.

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Article 14 â&#x20AC;&#x201C; Video Conferencing Etiquette

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

"Be on time!" Q-CTRL's Love said. "Better to be 10 minutes early, than a minute late."

7. Choose a quiet location It's easy to forget that there is a mic picking up not only your voice, but if you decide to eat/chew something, that sound will come through. If you make a cuppa tea, the sound of your cabinet opening and the dinging of the microwave will be amplified. Wait until the meeting is over. "Ambient noises can come through on your computer microphone, if it's not silenced," KnowB4's McQuiggan said.

And like most things, location, location, location: If you live on a busy street, if your meeting coincides with trash pickup, if you live next to a preschool (or it sounds like it), choose a different room to take the meeting.

"One of the biggest distractions on conference calls come from unmuted attendees," FlexJobs' Gardner said.

If your remote office is the local coffee house, consider that it might be too noisy, especially if you'll be competing with the ambient noise when delivering your update. Finally, if there is a mute-mic alternative, choose it, and only unmute when it's your turn to talk.

And who are we kidding? We definitely care about how we look, sheltering at home, to our colleagues. "If possible, sit somewhere with plenty of daylight, Around's Zane said. " We tend to feel more comfortable and look better--especially on an integrated laptop camera--in spaces with lots of natural light."

8. Place pets in another room A giant perk to working at home (if that's your remote office, and if you're sheltering at home) is having your pet around you. However, if your dog has a tendency to get the zoomies, your cats constantly battle for dominance, or your macaw screeches (and you may be used to it, but to others, it's horrifying): Put them in a different room. Your colleagues do not want to hear that, not only over your voice, but over anyone else's.

And be sure your pets are secured away/quiet before you call in to the conference call.

9. Stay on track Accustomed to constantly checking into social media? Love getting those Facebook, Twitter, Instagram, or TikTok updates? That all needs to be turned off during the meeting. "Multitasking is rude to the other participants in the meeting, who will be able to sense that you aren't fully engaged," Miro's Khusid said.

It may also be tempting to watch a captioned movie or show during the meeting, but proper etiquette deems you be 100% focused on the call. FlexJobs suggested you stand during the meeting while listening and talking, and even to stretch or do lunges to keep alert before you're asked to speak.

10. Speak up You may have a great connection, a crystal clear view of participants, and sound like you're in the same room. However, everyone won't have the same connection. Even if you can hear teammates perfectly well, it might not be so in the other direction. Always speak clearly and loudly (but of course, don't shout), and ask if you can be heard by everyone. This isn't the time to mumble or speak softly. It's a conference call, not an ASMR YouTube video.

11. Say your name Even if you have a Brady Bunch-esque grid of attendees in front of you, it's hard to keep track of who is saying what (hopefully the meeting leader established a way to avoid the seemingly inevitable over talking).

When you start talking, identify yourself, "This is Penelope, and I have a question," or "Hi, it's Jamison, I'd like to add to that point." FlexJobs said, "That way, your contributions to the conversation is noted, and no one is left wondering who the genius with the awesome comments is."

12. Use the mute button Again, inevitably, especially those who are wiggly/can't sit still for long, you don't want any scratching or odd sounds coming from you. Even if you're in a quiet location, mute yourself when you know you won't be called on. It's a lot easier to hit "unmute" than be known as the staffer who makes weird noises. An important element of conference call etiquette is not to let subtle distractions derail the person speaking or disrupt the conversation. Definitely turn off notification sounds--there's little more irritating than a constant dinging every time someone from your fantasy football league wants to weigh in on their picks or your worldwide family makes sure you are sheltering well.

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Article 14 â&#x20AC;&#x201C; Video Conferencing Etiquette

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

13. Silence isn't always golden Don't forget to unmute yourself when it's your time to talk, or everyone will see your mouth moving, your arms gesticulating but won't hear you. Someone (or all) will let you know, and everyone will laugh.

Keeping in touch while telecommuting Remember, too--if you're on an audio-only call--that people can't see you, so you can't nod in response or agreement. FlexJobs suggested you narrate what you're doing, so there aren't long stretches of silence while you're searching on your desk for a report, etc.

As of now, no one can predict how long the spectre of the coronavirus will require remote work or if it will bring to light the effectiveness of remote work.

Remote work shouldn't isolate, and contact amongst team members is critical. "The daily contact is more important than video," said Barry Po, president, Smart Facilities for mCloud Technologies. "Since our time is spread across many cities globally, we want to make sure everyone feels like they can reach out (virtually) anytime to anyone."

Yet others cite video as essential. "Just seeing the faces of colleagues on a daily basis maintains the lost personal connection that often accompanies remote workâ&#x20AC;?, Q-CTRL's Love said.

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Article 14 â&#x20AC;&#x201C; Video Conferencing Etiquette

PAPERmaking!

O THE PUBLISHERS U S S OF O PAPER TECHNOLOGY INTERNATIONAL FROM

Volume 6, Number 1, 2020

How to Ace a Remote Presentation According to a leading design firm, 80% of corporate presentations are now delivered remotely. Remote presentations offer both advantages and disadvantages. The decision about whether to present remotely may or may not be yours. Either way, it’s good to know the advantages and disadvantages, so you can prepare to be as effective as possible.

Harvard Business Publishing Staff https://hbrascend.org

The Paper Industry Technical Association (PITA) is an independent organisation which operates for the general benefit of its members – both individual and corporate – dedicated to promoting and improving the technical and scientific knowledge of those working in the UK pulp and paper industry. Formed in 1960, it serves the Industry, both manufacturers and suppliers, by providing a forum for members to meet and network; it organises visits, conferences and training seminars that cover all aspects of papermaking science. It also publishes the prestigious journal Paper Technology International and the PITA Annual Review, both sent free to members, and a range of other technical publications which include conference proceedings and the acclaimed Essential Guide to Aqueous Coating.

Page 1 of 3

Article 15 – Remote Presentations

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

Remote presentations give you important advantages as a speaker, such as: x x

Enabling you to reach a wider audience via internal networks, the internet, and social media sites Letting you interact with your listeners in new ways—including taking and answering their questions, following their comments online during the talk, and conducting contests. Thanks to chat-room capability, you can adjust your presentation on the spot.

On the downside, there’s always the possibility of technical difficulties in giving a remote presentation, such as poor audio or video quality. Or listeners may have trouble joining the presentation.

But most important, if you’re delivering your talk through audio only and not through Skype or other visual conferencing media, you can’t make eye contact with all your audience members. Even with visual conferencing, you can’t see their body language, and they can’t see yours.

Without that all-important nonverbal communication, your listeners may feel disconnected from you. As a result, they may have difficulty trusting you or lose interest in your talk.

These disadvantages make it harder to win—and keep—your audience’s attention during a remote presentation. In fact, a survey examining what people do while they’re attending webinars revealed that they spend more time checking e-mail than actually watching the presentations.

Captivate your audience To make your remote presentation more interesting to your listeners than their inboxes are, you need to: x x x x x

Simulate physical connection. Use props to make believe you are seeing your audience before you.

Excel at audio. Use your voice creatively.

Remove distractions. Anticipate and remove visual or auditory annoyances that could distract you or your audience from your talk.

Lure and re-lure your listeners. Regularly create a sense of contrast and offer intriguing bites of content in your talk.

Delight your audience. Show that you’re having fun, and display your individuality.

Simulate physical connection Seeing your audience helps you feel more connected to them. And when you feel connected, you adopt a warmer, more intimate, conversational speaking style that will hold your listeners’ attention. If you’re looking into a Webcam during your talk, your audience can see you—but you won’t see them.

Use a photo to remind you of your audience: Just under the camera on your computer, tape a photo of your actual audience members. If you’re speaking to a huge audience, use a photo representing your audience.

As you talk, look steadily into the camera and include the audience photo in your gaze.

If your audience will only be able to see your slides, make sure each one is uncluttered and shows only one idea. That way, the slides will be less distracting. They will also give listeners the sense that you, as a person, are organized and clear-thinking. That makes listeners trust you—which inspires them to keep listening.

Excel at audio In remote presentations, audio trumps visuals for holding an audience’s attention. So use your voice creatively. For instance: x x x

Stand up while delivering your talk. When you stand, your chest cavity fills with more air, making your voice richer and more rounded. You can also gesture more freely, which helps you speak in a more natural way.

Vary your voice. Vary the pitch and volume of your voice to reflect your message—such as using a higher pitch to convey excitement about an idea you’re discussing. Use pauses to convey a sense of drama and to make listeners curious about what you’ll say next.

Bring in other voices. If appropriate, invite other people to deliver parts of your talk or to engage in some casual conversation with you as you deliver your presentation. Hearing more than one voice is more interesting than hearing just one voice, especially during a lengthy presentation.

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Remove distractions By removing visual, auditory, and technology-related distractions, you can stay focused on your talk and avoid annoying or distracting your audience: x

x

x x x

Remove visual distractions. If you’ll be delivering your talk from an office with windows, cover them so you don’t notice people walking by. Put a sign on your door that says, “Recording in progress” or “Do not enter.” If you’re having trouble completing a thought and you’re running a chat session, cover the chat box with a piece of paper so you don’t feel compelled to look at listeners’ comments.

Remove auditory distractions. Turn off anything around you that will beep, buzz, or chirp, such as your mobile phone, reminders, or incoming e-mails. Avoid wearing chunky jewelry or accessories that could jangle or clank against your desk or other objects while you’re talking. If you tend to click your pen when you’re nervous, keep pens out of reach. Lay your notes out flat so you don’t have to rustle through your papers.

Have a techie nearby. Make sure you’ve got a tech-savvy aide—a colleague or IT person— standing by to resolve any technical difficulties that arise during your talk.

Have a moderator. If you’ve got a chat session going on during your talk or if you’re taking questions or asking listeners to complete polls, a moderator can process the incoming responses and prioritize them for you.

Distribute backups of your slides. Have copies of your slides on your desk, and also send your slide deck to audience members in advance of your presentation. That way, if your technology fails, you and your audience won’t get distracted by the fact that you have nothing to look at.

Lure and re-lure In a remote presentation, your “hook”—your compelling opening factoid, story, or statistic—won’t be enough to hold your audience’s attention throughout your talk. You need to keep re-luring your audience—drawing them back to you and the ideas you’re conveying.

To re-lure them, regularly create a sense of contrast and provide enticing content bites: x x x

Mix voice and media. Punctuate your talk with short videos, graphics, demonstrations, and other visual media.

Tell stories. Relate personal stories that help illuminate the ideas you’re conveying in your talk.

Stories draw people in, create a sense of suspense, and make listeners want to know more.

Create tension. Periodically acknowledge your audience’s “what is”—the problem they’re struggling with—and then describe “what could be” if they adopt the ideas you’re proposing. The tension created by the gap between what is and what could be will pique your listeners’ interest.

Delight and surprise Delighting your audience can help you further forge a human connection with them and keep them interested during a virtual presentation. Try these approaches: x

x

Convey your passion. Draw on the excitement and passion you feel for the ideas you’re communicating in your talk. Let that energy come through in your voice. Smile. The tone of your voice changes when you smile—listeners will be able to tell that you’re smiling, even if they can’t see your face.

Sneak in a game or contest. Use games and contests to keep your audience guessing about what else you have to offer. You could write a message on a slide or whiteboard that says, “The first one who tweets about this gets a free mug.” You’ll get your audience looking for additional opportunities to win fun prizes.

Adapted from “Presentation Skills” in Harvard ManageMentor.

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Article 15 – Remote Presentations

PAPERmaking!

O THE PUBLISHERS U S S OF O PAPER TECHNOLOGY INTERNATIONAL FROM

Volume 6, Number 1 2020

Products & Services PITA CORPORATE SUPPLIER MEMBERS Page 2

ABB

pH Sensors 2 Manufacturing Operations Software 3 Actuator 4 Optical Consistency Sensors 5 Lab Data Management System 7 New L&W Autoline 8

Page 9

Andritz

PrimeLineVTR 10

Page 10

Valmet

Lime Kiln Imaging System 11 Fibre Recovery & Thickening 12 New IQ Quality Management 12 Microwave Consistency 14 Microwave Total Solids 15

OTHER SUPPLIERS Page 16

Machinery

Page 18

Sensors / Testing / Analysis

The Paper Industry Technical Association (PITA) is an independent organisation which operates for the general benefit of its members â&#x20AC;&#x201C; both individual and corporate â&#x20AC;&#x201C; dedicated to promoting and improving the technical and scientific knowledge of those working in the UK pulp and paper industry. Formed in 1960, it serves the Industry, both manufacturers and suppliers, by providing a forum for members to meet and network; it organises visits, conferences and training seminars that cover all aspects of papermaking science. It also publishes the prestigious journal Paper Technology International and the PITA Annual Review, both sent free to members, and a range of other technical publications which include conference proceedings and the acclaimed Essential Guide to Aqueous Coating.

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pH SENSORS WITH ADVANCED ANALYTICAL CAPABILITY ABB has launched a new range of color-coded sensors that makes it easy to choose and manage the optimal pH measurement solution.

The application driven designs are categorized into three groups: the entry-level 100 series for cost-effective measurement in general process applications; the high-performance 500 series for harsh industrial applications; and the 700 series for specialist applications. This makes it simple for users to select, own, and operate the pH sensors best suited to their needs.

Digital and analog options are available, with the digital solution offering the greatest benefits because it provides advanced in-built diagnostics – the most effective way of ensuring constant high-quality water.

ABB’s EZLink plug-and-play technology links any of the new sensors to ABB’s digital transmitter range, including the recently launched AWT420. EZLink enables faster installation and commissioning and provides easy access to maintenance data meaning that users can replace sensors at the optimum time, saving money without risking process control.

Designed for long life to maximize process uptime, this new range incorporates innovations including ABB’s perpetual impedance diagnostics to detect electrode faults without the need for a solution earth. Another feature is the smart Reference Electrode Monitoring (REM) system, which provides early warning of electrode poisoning.

Optimal temperature compensation is assured by locating the pH electrode, reference electrode, and inbuilt temperature sensor together at the electrode tip. This provides a faster temperature response and better accuracy during calibration and in-process control applications.

To ensure accuracy and reliability in even in the harshest of processes, the new sensors are offered with ABB’s bespoke range of sensor glasses, specifically designed to meet requirements such as high pH levels, low or high temperatures, or the need for high acid resistance. General-purpose glass is offered for a range of aqueous media.

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ENHANCED MANUFACTURING OPERATIONS MANAGEMENT SOFTWARE The Manufacturing Operations Management (MOM) software suite powers streamlines production for increased productivity and profitability, enabling seamless plant orchestration.

The new version of ABB AbilityTM Manufacturing Operations Management will offer an extended range of capabilities and new digital applications. This flexible and secure software platform with a broad suite of industrial applications gives operators, supervisors and plant managers the visibility and insights to take the right actions for increased productivity, quality and compliance.

New features in the enhanced manufacturing operations management platform include: • Enhanced user experience based on new HTML 5 web client; • A new smart interactive dashboard application that provides greater visibility and collaboration; • A new statistical process control (SPC) application, to determine if each process is in a state of control; • A new Batch Compare application – for advanced batch analysis “ABB AbilityTM Manufacturing Operations Management is a comprehensive, scalable and modular software suite that optimizes visibility, knowledge and control throughout the operations domain,” said Narasimham Parimi, Head of Digital Products – Product Management, Process Control Platform. “This release provides a range of rich new functionality and a new enhanced user experience that enables operations to become more productive and responsive.”

ABB AbilityTM Manufacturing Operations Management is designed to simplify production management by enabling performance monitoring, downtime management and maintenance support, as well as providing statistical production analysis tools. It provides solutions and tools to facilitate the collection, consolidation and distribution of production, quality and energy information via the plant’s web-based reports, trends, and graphs.

A new, self-service dashboard application promotes increased collaboration, providing visibility from shop floor to top floor and spanning IT and OT environments. It increases data connectivity to all apps and modules within the MOM suite, combining historic and manufacturing data and providing the user with improved customization capabilities.

Dashboards can be shared amongst users, further promoting collaboration between teams.

Trends and events are displayed together, which enables customers to identify issues and opportunities enabling informed and timely decisions.

The new common services platform features an HTML 5 web platform that runs across all suites ensuring customers have a seamless user experience, so that applications can be viewed on different devices right down to a 10-inch tablet.

Statistical data process control (SPC) is used in manufacturing to determine if each process is in a state of control. The new SPC application works across all the different apps and modules and helps the user to improve quality and production related performance.

In addition to the existing Batch View and Batch Investigate features, a comparison option has been added to the platform’s batch analysis applications, allowing different types of comparison.

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Cyber security remains one of the key issues in the advancement of Industry 4.0, and the new features in MOM include enhanced security.

ABB Ability™ Manufacturing Operations Management is part of ABB AbilityTM, the company’s unified, cross-industry, digital offering — extending from device to edge to cloud — with devices, systems, solutions, services and a platform which enables customers to increase productivity and lower costs. ABB Ability™ was launched in 2017 and already offers more than 210 solutions. With an installed base of 70 million connected devices, 70,000 digital control systems and 6,000 enterprise software solutions, ABB is a trusted leader in the industrial space, and has a four-decade-long history of creating digital solutions for customers.

ACTUATOR IMPROVES EFFICIENCY, SAFETY AND PRODUCT QUALITY New Induction xP Plus is the paper industry’s most targeted, efficient and flexible induction heating actuator system for cross-direction (CD) caliper and gloss profile control.

Induction xP Plus actuator is aimed at paper and packaging manufacturers seeking a powerful, efficient, rapid-acting and safe method for controlling caliper on paper machines calenders.

Induction xP Plus rapidly ensures efficient heating up to 100 kW/meter in a highly-targeted area, providing unmatched flexibility for power density and heating zone width. It is the only caliper profiling system available with hybrid control zone configurations of 60 mm, 75 mm or 120 mm, enabling customers to target higher precision heat distribution at the edges, where it is often critical, as well as increasing heat density to get on spec quicker—even after sheet breaks.

“Induction xP Plus significantly enhances our offering as the only actuator featuring ABB’s unique power module technology, hybrid zones for targeted heat distribution and flexible layout configurations,“ said ABB product manager, Frank Condra. “The specification is developed to maximize paper quality and productivity, but crucially, includes an off-machine power module, enabling Induction xP Plus to meet the most stringent industrial safety requirements.”

An evolution of ABB’s highly-regarded Induction xP actuator, the new Induction xP Plus uses ABB’s uniquely efficient fixed frequency/soft switching technology which, in tandem with a lower voltage design, ensures negligible switching losses and lower stresses on electronic components. Induction xP Plus also features serial communications to the power modules, a three-phase power bus distribution system and advancements in the mower module and workcoil. These features combine to deliver the lowest CD caliper variation and associated improvements in reel build, while also providing the best sheet finishing for gloss, smoothness, and printability.

ABB’s Induction Profiler is an integral part of the ABB Ability™ Quality Management System, which is based on industry-leading ABB Ability™ System 800xA. By utilizing advanced measurement, control strategies and high-performance algorithms, ABB caliper and gloss control minimizes caliper and gloss variations under any operating conditions.

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OPTICAL CONSISTENCY TRANSMITTER SENSORS ABB has launched its KPM KC9 Optical Consistency Transmitter family, a new range of sensors that provide accurate measurement of total and/or ash consistency for better wet end measurement and control in pulp and paper processes. The sensors are suitable for pulp, paper, board and tissue manufacturers using virgin or recycled raw materials, particularly those using ash fillers, where only optical sensors are effective to measure ash consistency.

Available as either inline or bypass sensors, the entire KPM KC9 Optical Consistency Transmitter family offers the widest range of sensor options currently available and is best suited to measure the lowest consistency ranges. Providing reliable and accurate results, the sensors permit maintenance while processes are running, unlike other consistency sensors which require a shutdown and emptying of the process pipe.

The sensors work in tandem with ABB’s KPM KRA/KRT Retention Measurement System, used to monitor and control paper and board machine retention. Available in two options, the KRA unit measures white water total consistency as well as ash consistency. The KRT unit measures total consistency only.

“These new sensors employ unique measuring principles to ensure each application is covered cost effectively without compromising measurement accuracy,” said Per Sandstrom, Head of Lab and Process Testing Measurements, Pulp and Paper, Process Industries, ABB. “The sensors provide better control of deinking processes and machine wet end, enabling the highest proportion of on spec product with limited maintenance and lower installation costs.”

Besides its Optical Consistency Transmitter, ABB’s retention measurement system includes all necessary modules to ensure accurate and trouble-free measurement of headbox or white water stock, where consistency is so low that only optical technologies can be used. The

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system and sensors are part of ABBâ&#x20AC;&#x2122;s complete solution set for the wet end, including quality control, automation, advanced process control, instrumentation and much more.

The KPM KC9 Optical Consistency Transmitter range: Inline sensors The KPM KC9 inline consistency sensors are developed to measure single component fiber consistency in liquids from 0-14 percent.

Bypass sensors The KPM KC9 bypass consistency sensors are developed to measure consistency in liquids from 0â&#x20AC;&#x201C;5 percent.

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ABB LAB DATA MANAGEMENT SYSTEM ABB has launched its newest automated data acquisition and lab reporting solution, offering pulp and paper manufacturers rapid analysis of lab quality information, with reliable data storage, management and reporting. Purpose built for paper testing labs, the scalable, webbased L&W Lab Management System replaces ABB and other legacy systems, halves procedure times, and tailors lab reporting to users’ specific workflow preferences.

The system collects, analyzes and reports on information from lab instruments, as well as ABB’s L&W Autoline automated paper testing solution. It compares up to four paper properties and plots trends against previous batches. With instruments connected directly through a local area network (LAN), information is instantaneously accessible through any web-browser equipped device, via a user-friendly dashboard that shows sample data, trends, historical references and KPIs. This eliminates the need for desktop PCs connected to each instrument.

“Our new system is purpose-built for how labs operate,” said Per Sandstrom, head of lab and process testing measurements for ABB pulp and paper. “It will significantly reduce the manual work and IT infrastructure which is typical for lab operations in many mills. This is a tool that will help production and quality managers to immediately see and act upon a lab’s quality information to improve profit potential, which is our goal for all ABB customers.”

Results generated by the L&W Lab Management System can be exported as xml files to external mill-wide systems. Reports generated can also be integrated with the ABB Quality Data Management system and/or the ABB Ability™ Manufacturing Execution System to enable lab information to be included with other key process indicators.

Part of ABB’s end-to-end quality control solution for the pulp and paper industry, the L&W Lab Management System is suitable for mills seeking efficiency gains with automatic lab data collection, including those combining L&W Autoline automated paper testing with other standalone instruments, and larger mills needing to collect and export lab data to ERP/MES systems effectively.

ABB L&W Lab Management System dashboard

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NEW L&W AUTOLINE ABB launched its enhanced L&W Autoline automated paper testing system, scalable to fit any lab and user-friendly in operation for those new to automated testing. The fast, accurate solution optimizes quality control and minimizes operational costs for all papermaking operations.

For intuitive simplicity, L&W Autoline incorporates a unique, visual touchscreen interface, requiring minimal training to master. Other features include the smoothest and most reliable feeding system on the market, that pulls the samples through the machine to minimize jamming; a unique dual test function to reduce queuing by allowing simultaneous testing; high-volume information storage, enabling identification of quality trends over time; and realtime visualization, providing direct feedback to operators on the unit and throughout the mill.

The system—which can handle everything from sample preparation to the final reel report— radically reduces dependence on manual testing, enabling resources to focus on continuous and sustainable quality improvements while reducing quality control costs.

“Our pioneering L&W Autoline automated paper testing solution plays a crucial role in mill digitalization by enabling faster, smarter decision-making and process adjustments,” said Per Sandstrom, head of lab and process testing measurements for ABB pulp and paper. “With this system, customers gain the benefits of direct access to more information in less time, in a scalable package suitable for operations of all sizes.”

The speed at which the system gathers information and highlights off-spec data facilitates rapid process tuning 24/7, 365 days of the year. Visualizations are instantly available in real time to operations and engineering personnel both locally and remotely, to ensure production targets and quality specifications are fulfilled.

Building on the legacy of almost 50 years of automatic paper testing, L&W Autoline now comes in two different sizes: L&W Autoline S has a reduced footprint for smaller mills and those new to automated testing. L&W Autoline L is a larger unit, designed for more extensive testing requirements.

Both options share the same feature set, including sequential testing coupled with the ability to capture more than 100 quality parameters by CD position, providing a high quantity and quality of information for fast corrective action.

L&W Autoline is part of the ABB Ability™ Quality Management System (QMS) solution suite, ABB’s complete offering for optimizing paper quality.

For more information about the solution go to new.abb.com/pulp-paper/abb-in-pulp-andpaper/products/lorentzen-wettre-products/automated-paper-testing

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ANDRITZ LAUNCHES NEW VERTICAL CRESCENTFORMER The PrimeLineVRT features a vertical CrescentFormer in the forming section that enhances dewatering of the fiber web. This enables higher dryness right after the press section and an increase in paper caliper. Depending on the grade and basis weight of the paper produced, between two and four additional percentage points of dryness can be achieved after the press section compared to standard CrescentFormer configurations. â&#x20AC;&#x153;The advantage of this new technology is that we do not need additional fabrics and fabric loops or any extra space in the basement for installation of the equipment. This results in lower building costs as well as easier operation and maintenance compared to similar technologies on the market,â&#x20AC;? says Stefano Marenco, Director of PrimeLineTIAC and R&D Tissue at ANDRITZ. The PrimeLineVRT was developed and extensively tested at the ANDRITZ Tissue Innovation and Application Center in Graz, Austria. With this new technology that is tailor-made for significant improvement of dry crepe production, ANDRITZ once again confirms its strong position as one of the global market leaders for the supply of innovative key components used in conventional to ultra-premium grades within the tissue industry.

For more information about the PrimeLineVRT, contact us at tissue@andritz.com

The new VRT technology was developed and intensively tested at the ANDRITZ PrimeLineTIAC tissue pilot plant in Graz, Austria.

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VISIBLE IMAGING SYSTEM FOR PULP MILL LIME KILNS Valmet has launched a new Valmet Visible Thermal Imaging System, which provides the highest quality lime kiln process monitoring for pulp mills. Combining the camera temperature information with process controls can improve combustion optimization and reburned lime quality, and reduce emissions. The system also allows visual evaluation of flame shape, size, and temperature profile. Reduced maintenance costs and greater visibility during start-up and full load conditions can also be achieved.

The Valmet Visible Thermal Imaging System is a rugged, air-cooled, HD visible camera paired with a high-resolution thermal sensor for real-time product temperature measurements. Designed for comprehensive observation and analysis of kiln environments, the camera system provides unparalleled image quality from start-up to full load conditions. â&#x20AC;&#x153;There has been a very positive and enthusiastic use of this camera system during the initial pilot cases, most especially in observing and tuning the kiln burner flame during operation and start-up. It is exciting to see such an active customer engagement in using the camera features to monitor and improve their processes,â&#x20AC;? says Rodeo Winchell, Product Manager, Automation, Valmet.

The highest definition visible sensor results in superior image quality Valmet Visible Thermal Imaging Systems are engineered for durability and longevity inside of hot, dusty environments, providing a low maintenance solution to many complex process challenges. Optional automatic retraction hardware protects the camera from overheating in the cooling air loss. Digital-only data transmission improves the reliability of video streams, eliminating unwanted noise or image signal degradation.

The Valmet Visible Thermal Viewer software combines the HD visible image with a highresolution thermal sensor array. With up to eight customizable regions of interest for calculating temperature, users have full control over their data. Coupled with a user-friendly interface, it is simple to record images, view historical data trends, and configure temperature threshold alerts.

Read more: https://www.valmet.com/kilncamera

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NEW SOLUTION FOR FIBER RECOVERY AND PULP THICKENING Valmet announces the launch of Valmet Pressure-fed Bow Screen, a versatile new addition to its stock preparation offering. The solution reinvents the traditional bow screen with a new, user-friendly design and improved nozzle arrangement enabling higher capacity and greater runnability than before.

Working to maximize the effectiveness of fiber recovery and pulp thickening processes, Valmet Pressure-fed Bow Screen is ideal for tissue making applications. Other primary applications of the equipment include shower water protection filtration, police filtration, felt hair removal and deinking stock washing.

“A primary driving force behind the new design was our goal to provide a better, safer user experience for our operators at the mill level,” explains Tony Bjorkenius, Business Manager, Disc Filters, Services, Valmet. “The equipment is engineered to provide better accessibility than ever before, with the focus on service, maintenance and everyday use.”

Valmet Pressure-fed Bow Screen is the company’s first new product that specifically leverages the technology, engineering and expertise gained from the acquired company GL&V. The product launch reinforces Valmet’s services approach “Shared Journey Forward”, a set of commitments that promises customers solutions built on their unique needs, safety, trust and accessibility.

For further information, please contact: Tony Bjorkenius, Business Manager, Disc Filters, Services, Stock Preparation, Valmet, tel. +46 8 522 444 56, tony.bjorkenius@valmet.com

NEW VALMET IQ QUALITY MANAGEMENT Valmet introduces a renewed Valmet IQ Quality Management System for pulp, tissue, paper, board, and converting industries. The renewed system lets papermakers optimize quality through the entire value chain from fiber to finished product, enabling improved process performance and increased savings through the process.

The quality management system takes a step towards an autonomous mill The renewed Valmet IQ Quality Management System utilizes Valmet’s latest innovations and expertise on pulp and paper quality management. It integrates the quality management of the entire production process and is a step towards an autonomous mill. The new capabilities of Valmet IQ increase the degree of automation and reduce the human role in the process.

“Valmet IQ extends from traditional quality controls to the retention and refining online optimization with wet end analyzers. The new moisture management solution optimizes the drying process from the wire-former section through the press and dryer section to the end of the reel. It will stabilize the process and improve the performance even further,” says Marko Toskala, Director, Quality Management Systems from Valmet.

Valmet IQ consists of all the devices and applications needed to monitor and optimize both process performance and end-product quality: scanners, measurements, profilers, machine vision, and quality control applications.

The new quality scanner family is redesigned for even more demanding production environments. All Valmet IQ scanners now consist of stainless-steel exterior, enhanced

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diagnostics, and a new flexible sensor platform. New IQ Dryness and IQ Multipoint measurements reveal the true dryness development from the headbox to the reel. The IQ family is completed by the most advanced machine vision system on the market, enabling faster detection of even smaller quality defects. The renewed Valmet IQ is compatible with the previous generations. All Valmet IQ products are developed and manufactured in Finland.

The new Valmet IQ is also compatible with the recently introduced Valmet DNA User Interface, the new web-based user interface of the Valmet DNA automation system. The new structured user interface guides the operators to focus on the situation critical information and make the right decisions instantly – helping to optimize quality faster.

Automatic optimization saves raw materials, chemicals and energy Valmet IQ connects seamlessly with Valmet’s industrial internet (VII) solutions. With the cloud-based solution, the quality data moves from paper mills to converting, automating the optimization of the entire value chain. Similarly, paper producers can utilize feedback directly from the converting process while optimizing production performance and costs.

“Our customers have moved from reactive to data-driven quality management and witnessed significantly more stable production quality and decreased amount of broke. The automatic optimization of the entire value-chain has increased the production performance while simultaneously saving raw materials, chemicals, and energy”, Toskala continues.

Learn more about Valmet IQ at https://www.valmet.com/automation/quality-management/

The renewed Valmet IQ Quality Management System connects the quality data from fiber to finished product and takes a step towards an autonomous mill.

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VALMET LAUNCHES MICROWAVE CONSISTENCY MEASUREMENT Valmet launches a completely redesigned Valmet Microwave Consistency Measurement – Valmet MCA (patent pending) for pulp and paper makers. Valmet MCA is now provided by digital electronics and the new Direct Sweep Detection measurement to offer higher performance measurement sensitivity and accuracy than competing analog designs.

A wider applicability with the new Twin Blade sensor Valmet MCA’s new Twin Blade sensor complements the offering, along with the newly redesigned Flow Through sensor, by allowing paper and pulp makers to install it in larger pipe diameters. The Flow Through sensors are totally interchangeable with earlier installations.

With a wider applicability, the new Twin Blade sensor can also be used to measure unscreened pulp. The sensor’s completely redesigned clamp mounted probe is suitable for the much higher conductivity environment of chemical pulping.

“This new measurement technology is a leap forward in terms of performance and usability.

For long Valmet has been the market leader in microwave consistency measurements with more than 6,000 deliveries. The new Valmet MCA now leads the way for all pulp and paper needs,” says Marko Heikkinen, Product Manager, Automation business line, Valmet.

The new and easy-to-use operating unit Commissioning and operation have also been enhanced with the Valmet Bridge user interface, a new 7’’ touch screen control platform designed for use with Valmet process sensors and analyzers. With comprehensive diagnostics, Wi-Fi and Industrial Internet ready capabilities, Valmet Bridge user interface provides a user-friendly experience and intuitive access to transmitter operation and remote services from Valmet.

The industrial standard in total consistency measurement Valmet MCA measures total consistency of the pulp process stream independent of fiber length, freeness, wood species or blend. The measurement is not affected by flow rate, brightness or color and enables better control for more efficient production, improved quality and economic savings with fewer process upsets and less off grade product. With low lifetime costs, the sensor is simple to install and requires no regular maintenance to keep commissioning and running costs to a minimum.

Read more: https://www.valmet.com/valmetmca

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VALMET LAUNCHES NEW MICROWAVE TOTAL SOLIDS MEASUREMENT Valmet launches a completely redesigned Valmet Total Solids Measurement – Valmet TS (patent pending) for municipal and industrial wastewater treatment plants. Valmet Total Solids Measurements have gained an excellent reputation in wastewater treatment plants around the world for solids pumping control, thickening, digesting, dewatering and dry cake applications.

Now with the latest technology and materials, the new Valmet Total Solids Measurement is set to continue being the industry leader in microwave total solids measurements. New digital electronics replace the previous analog design which, together with the new Direct Sweep Detection measurement technology, further improves measurement sensitivity and accuracy with much higher resolution than earlier.

“The new measurement is a leap forward in terms of performance and usability. We have had outstanding success in wastewater industry with close to 2,000 measurements installed, which we can now build on as well as extending our efforts to industrial wastewater applications,” says Marko Heikkinen, Product Manager, Automation business line, Valmet.

New applications The Valmet TS flow through sensor, totally interchangeable with earlier installations, is available in standard version with various sizes from 50 to 300 mm and high-pressure versions from 100 to 200 mm. For larger diameter pipelines a new Twin Blade sensor is available.

The new measurement is insensitive to component aging or temperature effects and can now be used in the much higher conductivity environment of industrial wastewater treatment. All sensor models are also Ex certified, expanding the areas of application considerably. A special non-stick lining provides increased resistance to contaminate build-up and helps to provide a maintenance-free installation.

Easy to use Valmet TS utilizes microwave technology to determine total organic and inorganic solids content in the range of 0 to 50 percent. The single point calibration takes only a few minutes with an integrated pressure measurement providing the possibility to compensate for bubbles.

Commissioning and calibration are now enhanced with the Valmet Bridge user interface, a touch screen control unit designed for use with Valmet measurements. With comprehensive diagnostics and Industrial Internet ready capabilities, the new user interface provides an easy-to-learn and intuitive access to measurement operation and remote services from Valmet.

Read more: https://www.valmet. com/valmetts

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MACHINERY

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Volume 6, Number 1, 2020

NIDEC ASI SERIES OF VARIABLE FREQUENCY DRIVES The new VFD AFE transformerless medium-voltage drives of the SVFH series are characterized by extremely high efficiency and can be connected quickly and directly to the grid. By eliminating the transformer, Nidec has been able to make the drives 30% more compact and about 60% lighter than solutions incorporating a transformer, reducing not only energy consumption but also the use of metals difficult to dispose such as copper and iron.

The ultimate goal of the new solution presented at ADIPEC is that of guaranteeing maximum efficiency, maximizing the transfer of electricity from the grid to the load and vice versa. In fact, the VDF AFE is able to perform regenerative braking of the motor load, power factor correction and regeneration. In this way, the drive can send the electricity back to the grid without having to dissipate it, thus eliminating any waste.

Another important innovation in the VFD AFE is connectivity. In fact, these drives come with a dedicated app featuring a simple and intuitive interface which can be installed on any smartphone making it possible for the user to monitor system operation, schedule maintenance and guarantee immediate interventions even in remote mode, simplifying use for all operators, even the least expert.

"It is we who, with our daily actions and intuitions, are defining what our future and that of next generations will be like. This is why in Nidec ASI we ask ourselves every day what can and what must our contribution be to the energy transition towards tomorrow's world, which must be characterized by less consumption of raw materials and energy, if it is to be truly sustainable. This is why I am convinced that they will represent an essential element in the path towards the green and sustainable future of all industries around the worldâ&#x20AC;?, Dominique Llonch, CEO of Nidec ASI and Chairman of Nidec Industrial Solutions, declared.

Nidec ASI's new VFD AFE drives fit perfectly into the company's offer of customized solutions, ideal for all industrial sectors, representing a further and important step forward in the corporate strategy in the energy transition process towards an increasingly green and sustainable future.

Page 17 of 25

Products & Services

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

SENSORS / TESTING / ANALYSIS

Page 18 of 25

Products & Services

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

TURBIDITY SENSOR WITH IMPROVED DESIGN The EXspect 271 from the company EXNER is an NIR backscatter sensor for measuring turbidity. The sensor is distinguished not only by its cost-effectiveness, but also by its compact and durable design. It is suitable for determining medium to high turbidity values in a large number of applications, especially in the field of the food and beverage industry. The cleaning and sterilisation by means of CIP and SIP procedures are of course possible. A further advantage of the sensor is the spherical design of its measurement optics. This minimises the adhesion of air bubbles and the formation of deposits.

The compact sensor EXspect 271 has been available since February this year and has already proven itself in a wide variety of applications in dairies and breweries. Despite this, it has now been further improved. Thanks to design and productional optimisations it is now possible to use the sensor up to a process pressure of 16 bar (235psi).

https://e-p-e.com/

Page 19 of 25

Products & Services

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

SMART 3D LASER PROFILE SENSOR LMI Technologies (LMI), the global leader in 3D inline scanning and inspection, is pleased to announce that its Gocator 2512 3D laser line profile sensor, which is precision-engineered for scanning glass and specular surfaces, has been awarded Top Innovation 2020 by the prestigious German trade journal inVision.

Every year, inVision awards prizes to ten particularly innovative or trend-setting products from the fields of image processing, embedded vision, and 3D metrology. An independent jury classifies these products and solutions as worthy of recognition for outstanding technical innovation, usability, and the potential to penetrate new market segments.

The Gocator 2512 sensor was chosen by jurors for its unique ability to scan specular and diffuse surfaces simultaneously. This is a valuable capability in cell phone display assembly inspection where different types of specular (i.e., reflective) materials are present. In this particular application, the 2512 sensor is able to generate a precision 3D scan of the cell phone display glass in a surrounding metal or plastic frame, then deliver robust measurement and inspection of critical assembly tolerances such as flushness, gap, and offset.

In addition, Gocator 2512 leverages specialized laser projection technology that gives the sensor the flexibility to handle a wide range of surface angles, material types, and surface colors, which helps manufacturers minimize system downtime and operational costs incurred by frequent production cell changeover.

“It’s an honour to have the Gocator 2512 recognized by a jury of discerning experts. This award gives us even greater motivation to develop smart 3D solutions that address specific customer needs. Congratulations to all the winners this year, and happy innovating in the year ahead!” said Terry Arden, CEO, LMI Technologies.

To learn more about how LMI’s inspection solutions can benefit your business, we invite you to contact us at contact@lmi3d.com or visit us at www.lmi3d.com to explore the possibilities of smart 3D technology.

Page 20 of 25

Products & Services

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

ONLINE WALL THICKNESS MONITORING OF PULP MILL BLOW LINE In-service, high-temperature corrosion monitoring to provide increased asset intelligence to enhance productivity and minimise downtime.

Overview A solution to make wall thickness measurements of pipes, during operation, at a pulp mill was sought by, a world leader in manufacturer of tissue, pulp, paper and packaging.

Monitoring of remaining wall thickness of a blow line whilst in-service at temperatures cycling from ambient to 250 °C, several time a day was required to provide additional data and asset intelligence to the operations team, to directly increase productivity, enhance safety with increased measurement frequency and reduce inspection costs.

The Challenge The pulp making process exhibits some of the most extreme and challenging environments for plant integrity. There are corrosive chemicals, high temperatures and abrasive slurries.

Once the washed, cooked and hot wood chip pulp is prepared, it is discharged from the digester through a blow line to the blow tank. Accurate control and increased data of the pulp stock discharge can obtain higher yields, reduce chemical usage, increase throughput and produce a superior product.

Previously no solution had been found to monitor wall thickness to measure corrosivity or abrasion/erosion whilst being; a) Non-intrusive, non-destructive, and retro-actively installed. b) Operate in the harsh environment, up to 250 °C with rapid, multiple thermal cycles per day c) Offer intrinsically safe, explosive atmosphere protection from fine dust.

The Solution Working with a global provider of electronic solutions, the HotSense ultrasonic platform from Ionix was selected as the ideal solution to meet the needs of the blow line monitoring challenge.

Our HotSenseTM 380 sensor provides non-invasive, robust and stable ultrasonic wall thickness measurements across a wide temperature range (-55 to +380 °C) continuously, whilst mounted under insulation to fit congested areas where space is limited. Certified to the highest level of intrinsic safety, the sensor can operate in both explosive gas and dust environments.

Integrating the HotSenseTM transducer into the Molex ultrasonic monitoring electronics solution, the subsequent system was able to offer key advantages to paper mill operations team; • Waveform (A-scan) capture for analysis.

• Flexibility in communication protocols, wireless and wired, back to the control centre.

• High precision and accurate wall thickness measurements.

• Integrated, dynamic temperature compensation.

Execution A pilot site was identified to represent the 100s of pulp-mills across the USA sensors where 2 HotSenseTM sensors were installed on to a carbon steel NPS 10” Sch 40 blow pipe. A short, straight section of the blow line was prepared, removing a nominal 1 m section of insulation and a ~30 mm diameter patch was surface ground SA2.5 near white metal. The two sensors were deployed using the integrated HotSenseTM clamping system on the live blow line

Page 21 of 25

Products & Services

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

without the need for isolation or shutdown, in positions previously identified by historic maintenance and inspection.

Cabling was routed to the electronics data gathering system and connected. Data was collected over a period of 10 months to benchmark the wall thickness to operational requirements.

Highlights • Using HotSenseTM installed sensors offered reduced tolerances in wall thickness measurement realising better quality of data for plant operators • Increased data collection frequency provided better asset intelligence and increased safety.

• Reduced inspection costs by implementing monitoring and installed sensors under existing insulation.

• Proven capability in the hostile environment of the paper-mill, with high temperatures, fast cycling and explosive atmospheres.

Page 22 of 25

Products & Services

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

WIRELESS SENSORS ENABLE AUTOMATED MACHINE MONITORING SKF has released a compact and cost-effective vibration and temperature sensor for monitoring the condition of rotating parts on heavy industrial machinery. Designed principally for use as part of an SKF Rotating Equipment Performance (REP) solution, the sensor called the SKF Enlight Collect IMx-1 - enables customers to reduce both expensive unplanned downtime and their maintenance costs.

Product Line Manager at SKF, Chris James, says: "Industrial plants are under increasing pressure, and as a result, production hours are increasing. At the same time, our customers need to avoid unplanned downtime, while reducing their capital investments. Enabled by the new SKF Enlight Collect IMx-1 they can easily get started with a fee or performance-based contract, and access automated predictive maintenance and reliable rotation on their operating budget.

Powered by long-lasting batteries, this cost-effective sensor can be deployed in large numbers to automate the gathering of data regarding the health of machinery, a process typically carried out by technicians with manual portable devices. When mounted to a bearing housing, collected data can be wirelessly sent to a host computer network, where it can then be forwarded to cloud-based analysis services at SKF REP centres. Chris continues: “As a result, the new, highly accurate, robust sensors enable data to be collected more frequently over hours and days, instead of weeks and months - from locations that were previously inaccessible by hand, using fewer technicians.”

The system relies on a “mesh network”, which allows the sensors to relay data between one another. This means that data can be routed around radio obstacles, such as pipework and liquid storage vessels, that create signal blocks for conventional line-of-sight systems and sent over greater distances than would be possible using a single device. Chris explains: “The mesh network is self-forming, which makes it easier and quicker to deploy than other wireless communications technologies such as Wi-Fi or Bluetooth. It is also innovative in the way it manages available bandwidth and the power consumption of the sensors, which leads to a long enough battery life to meet the needs of our multi-year service contracts.”

The SKF Enlight Collect IMx-1 has been designed specifically to achieve a tough ingress protection rating of IP69K. This means it will work reliably when exposed to dust, dirt, oil, grease, contaminants, flying debris, temperature changes, wind, rain, high-pressure hot water washdowns and more.

“Critically, the sensor gathers data consistent with our manual data-collector, particularly when it comes to detecting early-stage bearing defects. Although severely damaged bearings are relatively straightforward to detect, by that stage they are close to failure - the key is to find defects early, so that corrective action can be planned in good time with minimal disruption”. However, extracting the tiny signals of an early-stage defect from background noise is difficult. The SKF Enlight Collect IMx-1 exploits SKF’s acceleration enveloping technology to achieve this.

Chris concludes: “Any condition monitoring programme is only as good as the measurements it takes. SKF has been executing predictive maintenance contracts on a large scale for decades, so we know how a wireless device needs to perform, and the result is the SKF Enlight Collect IMx-1. However, wireless devices in themselves do not deliver reliable rotation – that is achieved with the combination of analysis experience to provide machine insights and mechanical engineering competence to support execution of any corrective actions. And

Page 23 of 25

Products & Services

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

now delivered via new fee and performance-based business models, customers have a new way to achieve and pay for improved Rotating Equipment Performance.â&#x20AC;? www.skf.com/imx1 https://news.cision.com/skf/r/new-wireless-sensors-enable-automated-machine-monitoringfor-reliable-rotation-in-heavy-industries,c3069919

Page 24 of 25

Products & Services

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

BTG LAUNCHES CONTROLSUITE While plants invest significant amounts in in sensors, actuators, control systems, and advanced process control solutions, it is key to ensure that investments are maximized and bringing expected values. Today, one third of the process controllers installed operate in manual mode, and on average, one third of the loops in a given facility have equipment problem.

With CONTROLsuite, optimum performance is possible. Using CONTROLsuite in a facility will lead to improvement in the overall productivity (typically 4 to 8%), in the energy consumption (on average 1 to 2%), and in the quality of the final product.

CONTROLsuite provides a complete overview of loop performance throughout the entire facility. It identifies and prioritizes the loops that are not performing satisfactorily and identifies the root causes of loop issues. A toolbox for loop tuning is also available.

Read the CONTROLsuite brochure or watch the CONTROLsuite animation BTG Group is a multinational provider of integrated, highly specialized process solutions for the global pulp and paper industry. BTG is committed to help its customers achieve significant, sustainable gains in business performance.

Page 25 of 25

Products & Services

PAPERmaking!

O THE PUBLISHERS U S S OF O PAPER TECHNOLOGY INTERNATIONAL FROM

Volume 6, Number 1, 2020

Installations The following pages contain a summary of the various installations and orders from around the world of papermaking, wood panel and saw mills, and bio-power generation, received between the start of November 2019 and end of April 2020.

The Paper Industry Technical Association (PITA) is an independent organisation which operates for the general benefit of its members â&#x20AC;&#x201C; both individual and corporate â&#x20AC;&#x201C; dedicated to promoting and improving the technical and scientific knowledge of those working in the UK pulp and paper industry. Formed in 1960, it serves the Industry, both manufacturers and suppliers, by providing a forum for members to meet and network; it organises visits, conferences and training seminars that cover all aspects of papermaking science. It also publishes the prestigious journal Paper Technology International and the PITA Annual Review, both sent free to members, and a range of other technical publications which include conference proceedings and the acclaimed Essential Guide to Aqueous Coating.

Page 1 of 9

Installations

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

COMPANY, SITE

SUPPLIER

ORDER DESCRIPTION

URL

Ahlstrom-Munksjö (40 plants) Alas Doradas El Salvador Anon Brazil APP Guangxi Jingui Pulp and Paper Qinzhou Mill China APP Oki Mill Indonesia Asia Paper Manufacturing Sihwa Mill Republic of Korea Asia Pulp & Paper Sinar Mas Pindo Deli Mill Indonesia Avelino Bragagnolo S/A Santa Catarina Brazil

Tieto

TIPS software

Ahl-Tieto

Valmet

tissue production line including deinking plant and automation Turnkey chloride removal system for pulp mill coated board line (PM2) with automation and industrial internet

Alas-Valmet

PMP

four tissue machines

APP-PMP

Valmet

new sizing section

Asia-Valmet

PMP

rebuild of the press and dryer section

Asia-PMP

Hergen

AvelinoHergen

BCNonwovens Spain Berneck S.A. Lages Brazil BillerudKorsnäs Karlsborg Mill Sweden Bracell Lençóis Paulista Brazil “Star Project” Bracell Lençóis Paulista Brazil “Star Project” Bracell Lençóis Paulista Brazil “Star Project” Bracell Lençóis Paulista Brazil “Star Project” Bracell Lençóis Paulista Brazil “Star Project” Brasil Ltda Ortigueira Brazil “PUMA II” project

Andritz

expansion of PM3 including flat table extension, new suction couch roller, installation of 4 new pre-drying cylinders and 12 new post-drying cylinders spunlace line (nonwoven)

Andritz

pressurised refining and evaporation system (MDF line)

Berneck-And

SKF

partnering to reduce maintenance costs and improve production output and sustainability performance major wood processing plant (pulp mill)

Bill-SKF

Andritz

DSC and operator training simulator

Bracell2-And

Clyde Industries

boiler cleaning equipment

Bracell-Clyde

Pöyry

EPCM assignment to develop the BoP (Balance of Plant)

Bracell-Poyry

Valmet

key technology for a new pulp line

Bracell-Valmet

Andritz

dynamic simulation solutions, DCS checkout and operator training simulator

Brasil-Andritz

Veolia Valmet

Andritz

Page 2 of 9

Installations

Anon-Veolia APP-Valmet

BCN-Andritz

Bracell1-And

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

COMPANY, SITE BS Energy Braunschweig Germany Çamsan Entegre Turkey Cartiera Confalone Montoro Italy Cartiere Ermolli Moggio Udinese Italy Century Pulp & Paper Lalkuan India Chuetsu Pulp & Paper Sendai and Takaoka Pulp Mills Japan Dezhou Taiding New Material Science and Technology Co., Ltd. Dezhou China Dohaco Ben Tre Mill Vietnam Double A Prachinburi Thailand Eska Hoogezand plant Netherlands Essel Kağıt Osmaniye Mill Southern Turkey Gelo Timber GmbH Wunsiedel Germany Glatfelter Lydney Mill UK Gold HongYe Paper Hubei China Graphic Packaging International Kalamazoo Mill USA Green Bay Packaging Green Bay USA Grigeo Klaipėda Greece

SUPPLIER

ORDER DESCRIPTION

Valmet

biomass boiler and flue gas treatment plant

BSEnergyValmet

Valmet

defibrator system (MDF mill)

Toscotec

tissue line and automated warehouse

CamsanValmet Confal-Valmet

SAEL

water-cooled sectional drive (PM3)

Ermol-Sael

Valmet

evaporation line

CenturyValmet

BTG

bleaching control sensors

Chuetsu-BTG

Andritz

fibreline (P&W)

Dezhou-And

ABB

complete electrification and automation package

Dohaco-ABB

ABB

advanced process control (APC) for pulp mill

DoubleA-ABB

SPM

online condition monitoring systems

Eska-SPM

Toscotec

the country’s largest (5.7m) tissue line

Essel-Tosc

Holtec

log handling equipment and sawmill infeed (for new energy farm)

Gelo-Holtec

Bellmer

rebuild of dry end PM8 including delivery of softnip calender.

Glat-Bell

A.Celli

three rewinders

Gold-ACelli

Valmet

coated board machine

GraphicValmet

Konecranes

nine cranes

Green-Kone

Pöyry

an audit of environmental, occupational health and safety, and operational processes

Grigeo-Poyry

Page 3 of 9

URL

Installations

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

COMPANY, SITE Grupo Cordenons Cordenons PN Italy Grupo Gondi Guadalupe Mexico Guangxi Guoxu Group Co., Ltd. Wuzhou City Guangxi Province China Guangxi Shangsi Hualin Forestry Industry Co., Ltd China Gulf Ply Paper Co Dammam Saudi Arabia Hamburger Containerboard Spremberg Germany Hamburger Containerboard Spremberg Germany Helen Ltd Helsinki Finland Holmen (all mills, Sweden) Iggesund Paperboard AB Iggesund Sweden Ilim Group Ust-Ilimsk Mill Russia Irving Consumer Products USA JK Paper Ltd Central Pulp Mill Fort Songadh Mill India JK Paper Limited Fort Songadh Mill India JK Paper Limited Fort Songadh Mill India JK Paper Ltd Gujarat India JSC "Yarpaper" Yaroslavl Mill Russia

SUPPLIER SAEL

URL

rebuild drives and automation on Coating Machine 1, and Sheeter 2 in line with Coater 2.

OnCare.Asset workforce management software (for new PM7)

Corden-Sael

Andritz

pressurised refining system (MDF plant)

Guang-Andritz

Valmet

defibrator system (wood panel mill)

Guang-Valmet

ABB

mill-wide distributed control system (DCS)

Gulf-ABB

Andritz

three approach flow systems for PM2

Ham-Andritz

BTG

brightness and consistency transmitters for PM2

Ham-BTG

Valmet

plant and optimisation solution (bioenergy heating system)

Helen-Valmet

Pulpeye

ExtractEye

Holmen-Pulp

BTG

kappa analyser (hardwood pulp line)

Igg-BTG

Voith

kraftliner machine and Papermaking 4.0 digital package

Ilim-Voith

Valmet

TAD tissue machine (TM9)

Irving-Valmet

BTG

all speciality process measurement instruments

JKPaper-BTG

Valmet

JKPaper1Valmet

Valmet

board machine with extensive automation and industrial internet package complete mill-wide DSC

Projet BV

seven high pressure showers

JKPaperProjet

Toscotec

rebuild of PM1 (testliner)

JSC-Tosc

Voith

Page 4 of 9

ORDER DESCRIPTION

Installations

Grupo-Voith

JKPaper2Valmet

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

COMPANY, SITE

SUPPLIER

ORDER DESCRIPTION

URL

JSC "Yarpaper" Yaroslavl Mill Russia Karweb Nonwovens Gaziantep Turkey Karweb Nonwovens Gaziantep Turkey Kemira Chemicals Äetsä and Joutseno plants Finland Karweb Nonwovens Gaziantep Turkey Klabin ‘Puma II Project’ L-Pack Russia

Voith

extension to existing recycling line to PM1

JCS-Voith

A,Celli

Winding line for Spunlace (nonwovens)

Kar-ACelli

Andritz

Spunlace line (nonwovens)

Kar-Andritz

Valmet

energy management solutions

KemiraValmet

Andritz

spunlace line (nonwoven)

KarwebAndritz

Andritz

Klabin-Andritz

LD Celulose S.A. Minas Gerais state Brazil

Pöyry

LD Celulose S.A. Minas Gerais state Brazil Lecta Condat Mill France Lee & Man Chongqing China Lidköping Energi AB Lidköping Sweden Malaysian Newsprint Industries Sdn Bhd Malaysia

Valmet

concreting work for base of line 5 debarking drum rebuild of second hand machine including new press section and winder EPCM (Engineering, Procurement, Construction, Management) for the BOP (Balance of Plant) for the new dissolving pulp mill key process islands (dissolving pulp mill)

Allimand

rebuild of PM8

Lecta-Allim

Veolia

chloride and potassium removal system

L-M-Veolia

Valmet

waste-to-energy boiler (20MW TH)

Lidk-Valmet

Tieto

Malay-Tieto

Mayr-Melnhof Karton Frohnleiten Mill Austria Metsä Board Husum Pulp Mill Sweden

Andritz

selected as their business transformation partner, in particular to improve On Time In Full Delivery Service (OTIF) vertical screw thickener dewatering system new recovery boiler and upgrade of evaporator

HusumValmet

Bellmer

Valmet

Page 5 of 9

Installations

LPack-Bellmer

LD Cell-Poyry

LD Cel-Valmet

MMK-Andritz

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

COMPANY, SITE

SUPPLIER

ORDER DESCRIPTION

URL

Metsä Board Joutseno Mill Finland Metsä Board Kyro Mill Finland Metsä Fibre Kemi Mill Finland Metsä Fibre Kemi Mill Finland Metsä Fibre Rauma Finland Metsä Tissue Mariestad Mill Sweden Metsä Tissue (various sites) Millar Western Whitecourt Alberta USA MOPAK Kağıt Karton Dalaman Mill Turkey Nordic Paper (four mills)

Valmet

TwinRoll™ dewatering press

Jout-Valmet

Valmet

reel and winding technology

Kyro-Valmet

Pöyry

engineering services and project management contract for new bioproduct mill preliminary agreement for key technology and automation for planned bio-product mill engineering services contract for new saw mill

Kemi-Poyry

BHM Ingenieure

technical pre-engineering for site upgrade

MetT-BHM

Tieto

TIPS software

TetT-Tieto

Pulpeye

PulpEye QC system (BCTMP pulp mill)

Millar-Pulpeye

Andritz

MOPAKAndritz

Norske Skog Saugbrugs Mill Halden Sweden Orora Limited Botany Mill New South Wales Australia Pankaboard Finland Papel Aralar Amezketa Spain Papel Aralar Amezketa Spain Papel San Francisco Mexico

Pöyry

rebuild of PM3 (to convert from coated board to coated and uncoated white top testliner) agreement to improve productivity, health and safety and sustainability performance detailed engineering services for a major energy efficiency project

Valmet

maintenance contact for B9 boardmaking line

Orora-Valmet

Tieto

TIPS software

Panka-Tieto

Trützschler Nonwovens

AquaJet technology for spunlacing and a multi-drum drier for PM5

Aralar- Trutz

Voith

HydroFormer, stock preparation, master reel and wet end process for PM5 stock preparation and deinking line

Aralar-Voith

Valmet

Pöyry

SKF

Kadant Black Clawson

Page 6 of 9

Installations

Kemi-Valmet

Rauma-Poyry

Nordic-SKF

Norske-Poyry

PapSnFraKadant

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

COMPANY, SITE Papeles Ultra Mexico Papeterie Le Bourray Saint-Mars-la-Brière France Papierfabrik Palm GmbH & Co KG Aalen-Neukochen Mill Germany Papierfabrik Palm GmbH & Co KG Aalen-Neukochen Mill Germany Papierfabrik Palm GmbH & Co KG Aalen-Neukochen Mill Germany Papierfabrik Palm Aalen-Neukochen Mill Germany Papierfabrik Palm Aalen-Neukochen Mill Germany Papierfabrik Palm GmbH & Co KG Eltmann Germany Papierfabrik Palm GmbH & Co KG King’s Lynn UK Papierfabrik Palm GmbH & Co KG Wörth Germany PRAJ Industries India Qinzhou Lvyuan Wood Co., Ltd. Guangxi China Riau Andalan Pulp & Paper Indonesia Saint-Gaudens Pulp Mill France Saint-Gobain ADFORS Czech Republic Sappi Ngodwana South Africa SCA Obbola Mill Sweden SCA Obbola Paper Mill Sweden

SUPPLIER

ORDER DESCRIPTION

URL

Bellmer

modernisation of dryer section (PM1)

Toscotec

rebuild of PM4 (tissue)

PapUltraBellmer Bourray-Tosc

Andritz

complete reject treatment and sludge handling system

Aalen-Andritz

GAW Technol.

chemical preparation systems (PM5)

Aalen-GAW

Siemens

gas turbine, and complete electrification (PM5)

AalenSiemens

Valmet

Paper Lab automated testing laboratory (the 300th sold)

Aalen1Valmet

Valmet

Containerboard line (PM5) with automation

Aalen2Valmet

Siemens

gas turbine

Eltm-Siemens

Voith

heated calender rolls (PM7)

KL-Voith

Siemens

gas turbine

WorthSiemens

Valmet

PRAJ-Valmet

Veolia

biomass pretreatment system (biorefinery project) defibrator system and steam separator PV system (wood panel mill) chloride removal system

Veolia

evaporation system

StGa-Veolia

Andritz

wetlaid line (glass fibre mats)

StGo-Andritz

Projet BV

new dry edge trim system

Sappi-Projet

Valmet

fossil free lime kiln and upgrade of fibreline

SCA-Valmet

Voith

kraftliner packaging line

SCA-Voith

Valmet

Page 7 of 9

Installations

Quiz-Valmet

RAPP-Veolia

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

COMPANY, SITE Schoellershammer Düren Germany Shandong Sun Paper Industry Joint Stock Co., Ltd. Sun Paper China Siam Cement Group (mills in Thailand and Vietnam) Siam Cement Group Packaging (including subsidiaries in Southeast Asia) Silverton Pulp & Paper India Smurfit-Kappa Monterrey Mexico Sri Andal Paper Mills Tamil Nadu India Stora Enso Ostroleka Poland Stora Enso Oulu Mill Finland Stora Enso Oulu Mill Finland Stora Enso Skoghall Mill Sweden Sun Paper “Loas Project” Sun Paper Beihai China Sun Paper Shandong China Sun Paper Savannakhet Co., Ltd. Xepon China Tamil Nadu Newsprint and Papers Ltd Mondipatti Village Tamil Nadu India Tamil Nadu Newsprint and Papers Ltd. Mondipatti Village Tamil Nadu India

SUPPLIER

URL

Bellmer

Bio-sludge dewatering press

Schoel-Bell

Valmet

automation systems for PM39 and PM40

ShandongValmet

Projet BV

74 high pressure showers

Siam-Projet

Valmet

roll recovering service agreement

Siam-Valmet

Projet BV

high pressure tail cutter

Silver-Projet

Projet BV

two dryer fabric cleaners (PM1)

SK-Projet

Valmet

new containerboard line

Sri-Valmet

Projet BV

two dryer fabric cleaners (PM4)

Stora-Projet

AFT

POM wet end (PM7)

Stora-AFT

Valmet

Automation package for PM7 conversion

Stora-Valmet

Valmet

forming section rebuild

Stora-Valmet

ABB

drives for PM1 and PM2

Sun1-ABB

Valmet

Sun-Valmet

ABB

A fine paper making line with stock preparation, an extensive automation package and recovery boiler protection, drives and motors

A.Celli

three rewinders

Sun-Acelli

Andritz

recovery boiler, evaporation plant and white liquor plant

TNP-Andritz

Valmet

cooking and fibreline

TNP-Valmet

Page 8 of 9

ORDER DESCRIPTION

Installations

Sun2-ABB

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

COMPANY, SITE Temboard Temiscaming Canada Tampereen Sähkölaitos Oy Naistenlahti power plant Tampere Finland Tianjin Shengsong Wood Co. Ltd Tianjin China Tolko Industries High Prairie facility Alberta USA Toyo Engineering Corporation Honshu Island Japan TWE Meulebeke BVBA Belgium Umka Cardboard Mill Serbia Unibol S.A. Columbia United Pulp and Paper Co., Inc. Calumpit Mill Bulacan Philippines UPM Paso de los Toros Uruguay WestRock Co. Washington Mill USA Whakatane Mill Ltd New Zealand Zespół Elektrowni PątnówAdamów-Konin SA Konin Poland

SUPPLIER

ORDER DESCRIPTION

Projet BV

two dryer fabric cleaners

Tem-Projet

Valmet

biomass-fired boiler plant

TampereenValmet

Valmet

defibrator system (wood panel mill)

Tian-Valmet

Kadant

two pocket batch feeders for an OSB line upgrade

Tolko-Kadant

Andritz

fluidised bed boiler and gas flue cleaner (biomass power plant)

Toyo-Andritz

A.Celli

spooling line (nonwovens)

TWE-ACelli

Valmet

board machine rebuild (PM1)

Umka-Valmet

Overmade

MG paper machine and winder

Unibol-Over

Andritz

OCC pulping line (capacity 870admt/d)

UPP-Andritz

Andritz

main technology for new pulp mill

UPM-Andritz

ABB

dry end drive system replacement

WestR-ABB

Valmet

renewal of service agreement for PM3 convert a lignite-fired boiler into a biomass-fired boiler at this power plant

Whak-Valmet

Valmet

Page 9 of 9

URL

Installations

Zespol-Valmet

PAPERmaking!

O THE PUBLISHERS U S S OF O PAPER TECHNOLOGY INTERNATIONAL FROM

Volume 6, Number 1, 2020

Research Articles Most journals and magazines devoted to the paper industry contain a mixture of news, features and some technical articles. Very few contain research items, and even fewer of these are peer-reviewed.

This listing contains the most recent articles from the four remaining specialist journals that publish original peer-reviewed research: x x x x

APPITA JOURNAL IPPTA JOURNAL NORDIC PULP & PAPER RESEARCH JOURNAL TAPPI JOURNAL

Notes: 1. In 2019 APPITA JOURNAL separated from the APPITA MAGAZINE and is now only available as an electronic publication; it is still protected by a paywall.

2. IPPTA JOURNAL is available online free of charge around 6-9 months after publication.

3. The excellent J-FOR+ from Canada ceased publication in late 2018.

4. NORDIC PULP & PAPER RESEARCH JOURNAL remains available only behind a paywall.

5. Finally, TAPPI JOURNAL went open-access in 2020.

The Paper Industry Technical Association (PITA) is an independent organisation which operates for the general benefit of its members – both individual and corporate – dedicated to promoting and improving the technical and scientific knowledge of those working in the UK pulp and paper industry. Formed in 1960, it serves the Industry, both manufacturers and suppliers, by providing a forum for members to meet and network; it organises visits, conferences and training seminars that cover all aspects of papermaking science. It also publishes the prestigious journal Paper Technology International and the PITA Annual Review, both sent free to members, and a range of other technical publications which include conference proceedings and the acclaimed Essential Guide to Aqueous Coating.

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Research Articles

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

APPITA JOURNAL, Vol.72, No.4, October-December 2019 1. The end of an era 2. Controllable pore structure and physical Properties of Nanofibrillated Cellulose (NFC) - based foam materials 3. Chemistry of dithionite bleaching. Part 1. Effect of bleaching variables 4. Chemistry of dithionite bleaching. Part 2. Comparable study with different thermomechanical and recycled fibre pulp 5. Identification of actuator mapping in cross-directional basis weight control of the papermaking process IPPTA JOURNAL, Vol.31, No.2, April-June 2019 1. Developments towards improving Paper Quality & efficiency for Mid Segment Paper Mills 2. Green Chemistry to enhance Pulp Bleaching 3. Innovative Developments in Coating for Making Flame Retardant Paper and their Kinetic Study 4. Justice to Fiber-Preparation to Extract Full Potential of Strength Properties by Applying Advanced Technology 5. Lignin Separation From Black Liquor of Agro based Medium and Small Scale Paper Industry for Sustainable Development 6. New Approaches to Technology Development and Trouble Shooting 7. Qualitative and Quantitative Benefits of Installing Steam Profiler 8. Quality and Productivity Improvement through Business Process Re-Engineering / Re-Orientation 9. Improvement in strength properties of packaging paperboard using biopolymer chitosan following a green approach 10. Some experiences in trouble solving 11. The Influence of Super Masscolloider and Lab valley beater on the Morphology of Sapwood Pulp Fibres 12. Using Concentrating Solar Thermal Technology to integrate with Industrial process to reduce the dependence of fossil fuels 13. Water- Recycle and Reuse with Waste Water Management Techniques NORDIC PULP & PAPER RESEARCH JOURNAL, Vol.34, No.4, December 2019 1. Review: A broad overview on innovative functionalized paper solutions 2. Chemical Pulping: Suitability of eight years kadam tree (Neolamarckia cadamba) in chemical pulping 3. Bleaching: Using Oxone and TAED activator in non-chlorine bleaching of soda bagasse pulp 4. Bleaching: Impact of dissolved organic matter in D0- and AD0-stages in bleaching of birch kraft pulp 5. Paper Technology: Effects of a stylus on the surface roughness determination in a contact method for paper and paperboard 6. Paper Technology: Structure analysis of three non-wood materials for liner paper 7. Paper Chemistry: The influences of chlorhexidine and modified galactomannan additions on the physical and antibacterial properties of paper 8. Paper Chemistry: Optimization of the process variables for treating cellulose fiber with NaOH/urea aqueous solution for improved water retention value and paper strength 9. Paper Chemistry: The application of organosilicon modified polyurethane in reinforcing traditional paper

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Research Articles

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

10. Paper Chemistry: Effect of ionic liquid pretreatment on paper physical property and pulp refining performance 11. Coating: Antibacterial effect of Ag nanoparticles into the paper coatings 12. Coating: Facile fabrication of hydrophobic cellulosic paper with good barrier properties via PVA/AKD dispersion coating 13. Printing: Enhanced ink-absorption performance of inkjet printing paper-based patterns with core-shell-structure CaCO3{\mathrm{CaCO}_{3}}@SiO2{\mathrm{SiO}_{2}} pigments 14. Printing: Application of gradient method for separately analyzing optical and mechanical dot gain of electrophotography prints 15. Printing: Effect of the paper surface properties on the ink transfer parameters in offset printing 16. Environmental Impact: Novel methods for monitoring the sludge dewatering operation of a belt filter: a mill study 17. Lignin: Structural characterization of the bagasse lignin pretreated using solid alkali NORDIC PULP & PAPER RESEARCH JOURNAL, Vol.35 No.1, March 2020 1. Review: On the development of the refiner mechanical pulping process – a review 2. Bleaching: Oxalate formation during ClO2 bleaching of bamboo kraft pulp 3. Mechanical pulping: Defibration mechanisms and energy consumption in the grinding zone – a lab scale equipment and method to evaluate groundwood pulping tools 4. Paper Technology: Insight into fractionation performance of American old corrugated containers pulp in pressure screening 5. Paper Technology: Comprehensive utilization of Ganoderma lucidum residues in papermaking 6. Paper Technology: Effect of turbulence generator structures to the performance of medium-consistency pump at high rotation speed excesses 2000 rpm 7. Paper Technology: Mechanical properties of low-density paper 8. Paper Technology: Determination of relative solids concentration in homogeneous dual component pulp-filler suspension by multi-spectrophotometer 9. Paper Physics: Surface characterization of paper and paperboard using a stylus contact method 10. Paper Chemistry: Filler modified by a sequential encapsulation and preflocculation method and its effect on paper properties 11. Paper Chemistry: Significant contribution of fibrils on pulp fiber surface to water retention value 12. Paper Chemistry: Impregnation of paper with cellulose nanofibrils and polyvinyl alcohol to enhance durability 13. Printing: Vibration measurements of paper prints and the data analysis 14. Printing: Predicting inkjet dot spreading and print through from liquid penetrationand picoliter contact angle measurement 15. Environmental Impact: Hydrophobic cellulose aerogel from waste napkin paper for oil sorption applications 16. Environmental Impact: A comparative study of an anaerobic-oxic (AO) system and a sequencing batch biofilm reactor (SBBR) in coating wastewater treatment and their microbial communities

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Research Articles

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

TAPPI JOURNAL, October 2019 1. Editorial: TAPPI Journal goes Open Access in 2020 2. Evaluation of novel drum chipper technology: pilot-scale production of short wood chips 3. The solubility of calcium carbonate in green liquor handling systems 4. Exergy and sensibility analysis of each individual effect in a kraft multiple effect evaporator TAPPI JOURNAL, November 2019 1. Editorial: Diverse content characterizes PaperCon 2019 2. Multiple recycling of paperboard: Paperboard characteristics and maximum number of recycling cycles â&#x20AC;&#x201C; Part I: Multiple recycling of corrugated base paper 3. Rheological characterization of tack and viscoelasticity of compositions of crepe coating used in the Yankee dryer 4. A novel predictive method for filler coflocculation with cellulose microfibrils 5. Lignin-based resins for kraft paper applications 6. Creating adaptive predictions for packaging-critical quality parameters using advanced analytics and machine learning TAPPI JOURNAL, January 2020 1. Editorial: TAPPI Journal research highlights from 2019 2. Effects of different ammonium lignosulfonate contents on the crystallization, rheological behaviors, and thermal and mechanical properties of ethylene propylene diene monomer/polypropylene/ammonium lignosulfonate composites 3. A new approach for the preparation of cellulose nanocrystals from bamboo pulp through extremely low acid hydrolysis 4. Root cause analysis of cationic polymer additive efficiency decline in virgin and recycle containerboard mills 5. Wheat straw as an alternative pulp fiber TAPPI JOURNAL, February 2020 1. Editorial: A PaperCon preview of whatâ&#x20AC;&#x2122;s coming in April 2. On increasing wet-web strength with adhesive polymers 3. Stiffness and strength properties of five paperboards and their moisture dependency 4. The winding mechanics of laminate webs 5. Investigation on the recycling of sulfuric acid from pretreatment of cellulose for nanocellulose preparation TAPPI JOURNAL, March 2020 1. Editorial: TAPPI Journal 2019 Best Research Paper addresses hard scale formation in green liquor pipelines 2. Understanding extensibility of paper: Role of fiber elongation and fiber bonding 3. Fate of phosphorus in the recovery cycle of the kraft pulping process 4. Synthesis of filtrate reducer from biogas residue and its application in drilling fluid 5. Historical perspectives of corrugated box testing for 2020

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Volume 6, Number 1, 2020

TAPPI JOURNAL, April 2020 1. Editorial: Snapshot from the pandemic: TAPPI Journal Editorial Board shares their experiences 2. How to use total dissolved solids measurements to evaluate the performance of diffuser washers â&#x20AC;&#x201C; A mill study 3. Papermaking properties of bacterial nanocellulose produced from mother of vinegar, a waste product after classical vinegar production 4. A novel unit operation to remove hydrophobic contaminants 5. Creasing severity and reverse-side cracking

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Research Articles

PAPERmaking!

O THE PUBLISHERS U S S OF O PAPER TECHNOLOGY INTERNATIONAL FROM

Volume 6, Number 1 2020

Technical Abstracts The general peer-reviewed scientific and engineering press consists of several thousand journals, conference proceedings and books published annually. In among the multitude of articles, presentations and chapters is a small but select number of items that relate to papermaking, environmental and waste processing, packaging, moulded pulp and wood panel manufacture. The abstracts contained in this report show the most recently published items likely to prove of interest to our readership, arranged as follows: Page 2

Coating

Page 2

Energy / Environment

Page 3

Moulded Pulp

Page 4

Nano-Science

Page 5

Novel Products

Page 7

Packaging Technology

Page 9

Paper Chemistry

Page 10

Paper Process

Page 12

Printing Pulp / Pulping

Page 14

Recycling

Page 15

Testing

Page 17

Tissue

Page 18

Waste Treatment

Page 21

Wood Panel

The Paper Industry Technical Association (PITA) is an independent organisation which operates for the general benefit of its members â&#x20AC;&#x201C; both individual and corporate â&#x20AC;&#x201C; dedicated to promoting and improving the technical and scientific knowledge of those working in the UK pulp and paper industry. Formed in 1960, it serves the Industry, both manufacturers and suppliers, by providing a forum for members to meet and network; it organises visits, conferences and training seminars that cover all aspects of papermaking science. It also publishes the prestigious journal Paper Technology International and the PITA Annual Review, both sent free to members, and a range of other technical publications which include conference proceedings and the acclaimed Essential Guide to Aqueous Coating.

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Technical Abstracts

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

COATING Water and Oil Resistance Improvement of Paper Coated with Aqueous Mixture of Hydrophilic and Hydrophobic Cross-Linked Copolymers, Zhaoping Song et al, BioResources, Vol.15(2). An aqueous mixture of hydrophilic and hydrophobic crosslinked copolymers was prepared and coated on the surface of filter paper to improve the water and oil resistances. The mixture was mainly composed of sodium alginate and hydroxyl-terminated polydimethylsiloxane (PDMS)-tetramethoxysilane (TMOS) crosslinked network. The results indicated that the resistances to both water and oil of the resulting paper were significantly enhanced. The water contact angle results demonstrated that the mixture enhanced the hydrophobic properties of the coated paper greatly with water contact angles higher than 110°, and the coated paper showed excellent oil resistance with a Kit number as high as 10.

Effect of Recycled Polystyrene/Limonene Coating on the Mechanical Properties of Kraft Paper: A Comparative Study with Commercial Coatings, M. Jimenez-Francisco et al, Journal of Polymers and the Environment (2020), online. In this work, the mechanical properties of Kraft paper (KP) coated with a coating formulated with recycled polystyrene dissolved in the solvent lime limonene (rEPS/LL) are investigated. These mechanical properties are compared with those of KP coated with three different commercial coatings: oil-based alkyd coating (ALKY), oil-based phenolic coating (PHEN) and water-based acrylic coating (ACRY). The morphology characterization via scanning electron microscopy showed the KP coated with rEPS/LL resembles a layered structure, in which, part of the coating remained on the surface and part of the coating was absorbed by the KP. The KP coated with rEPS/LL exhibited the highest tensile stiffness and compression strength when compared to the uncoated KP and KP coated with commercial coatings. The remarkable compression properties of the KP coated with rEPS/LL coating may be explained by the bending and crushing mechanisms observed during the ring crush test. The excellent mechanical performance of rEPS/LL combined with an environmentally friendly process to obtain recycled EPS using a bio-based solvent presents several advantages for coating applications. These results warrant further research to fully understand the properties of KP coated with rEPS/LL. ENERGY / ENVIRONMENT CostǦSaving Opportunities in the Energy Management of Papermaking Processes, Ján Janošovský et al, Chemical Engineering & Technology (2020), online. Energy consumption optimization belongs to the main agendas in sustainable industries. Here, costǦsaving opportunities in the pulp and paper industry as one of the largest industrial energy consumers worldwide are in the focus. EnergyǦsaving measures are proposed employing a largeǦscale mathematical model of a paper machine based on mass and energy balances supported by realǦtime experiments in paper machine operation. The presented measures are based on the optimization of paper stock pumping and a drying section operation. The total energyǦsaving effect of the four proposed measures accounted for a reduction in specific heat and electricity consumption by more than 2 %.

The proposed procedures require no or low investment costs with the overall simple rate of return of less than one year.

Life cycle cost assessment of recycled paper manufacture in China, Jigeng Li et al, Journal of Cleaner Production, Vol.252. Recovered paper is one of the major raw material for recycled papermaking industry. In China, the domestic recovered paper recycling system is incomplete and the amount of recyclable recovered paper cannot satisfy the papermaking demand. Therefore, the recycled papermaking industry is

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Technical Abstracts

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

extremely dependent on imported recovered paper as their raw fiber source. In 2018, Chinese government announced a ban on unsorted recovered paper and tightened the import quota for recovered paper, which resulted in a dramatic drop in the importing amount of recovered paper. It is an urgent issue to explore alternative production routes that are more economical and environmentally friendly. Herein, life cycle cost assessment is used to compare and analyze the recycled papermaking industry based domestic recovered paper and three alternatives (including straw, imported deinked pulp and imported wood pulp) as the raw materials. The results show that the life cycle cost of domestic recycled paper based recovered papermaking is significantly lower than the other three alternatives, whereas its external cost is higher than that of the production routes based on the imported deinked pulp and imported wood pulp. With the increasing price of the domestic recovered paper, imported deinked pulp is the trend of recycled papermaking industry in China.

Multi-criteria decision making for sustainability assessment of boxboard production: A life cycle perspective considering water consumption, energy consumption, GHG emissions, and internal costs, Yi Man et al, Journal of Environmental Management, Vol.255. Papermaking is a capital-intensive industry that requires a high consumption of plant fibers, energy, and water. Previous sustainability assessments of papermaking industry primarily focused on separate evaluations for multiple criteria without the integration for criteria and could not compare the overall priority of the production alternatives. The life cycle sustainability for the most representative boxboard production is analyzed as a case study in this work. Life cycle water consumption, energy consumption, greenhouse gas emissions, and internal costs are selected as the assessment criteria. The two multi-criteria decision-making methods are applied to integrate the above criteria to obtain the sustainability sequence under different production pathways. When the papermaking enterprises are regarded as decisionmakers, the alternative using waste paper as raw material to manufacture boxboard is the most sustainable, following by mixed fiber. The sustainability sequence of the alternatives using wood and straw as raw materials is controversial due to the different calculation models. Changing the proportion of raw materials and the criteria weights might adjust sustainability sequence of the alternatives.

MOULDED PULP Poisson’s ratios of molded pulp materials by digital image correlation method and uniaxial tensile test, Guangjun Hua et al, Journal of Engineered Fibers and Fabrics (2020), online. The mechanical properties of molded pulp materials are the basis of the structural optimum design of molded pulp products. Therefore, the correlations between Poisson’s ratio and fiber structure, molding process, and thickness were found for materials including wood pulp, bamboo pulp, sugarcane pulp, white mixed pulp, black mixed pulp, recycled corrugated board pulp, and recycled newspaper pulp by the uniaxial tensile test and digital image correlation method. The fiber structures of the selected molded pulp materials were investigated by scanning electron microscopy. The results revealed Poisson’s ratios of wood pulp, bamboo pulp, sugarcane pulp, white mixed pulp, black mixed pulp, recycled corrugated board pulp, and recycled newspaper pulp to be 0.169, 0.108, 0.202, 0.120, 0.166, 0.098, and 0.044, respectively. Microstructural investigation further revealed that Poisson’s ratios of molded pulp materials were related to the fiber structure and drying method. The pulp material dried outside mold under lower pressure and temperature had a smaller Poisson’s ratio, while that dried inside mold under higher pressure and temperature had a larger Poisson’s ratio. The layered phenomenon of the molded pulp materials was also found by scanning electron microscopy images: the

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Technical Abstracts

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

outer layer was denser than the inner layer. These results can provide guidance for the numerical simulation analysis and optimal design of molded pulp products.

Soft tooling process chain for the manufacturing of micro-functional features on molds used for molding of paper bottles, Prateek Saxena et al, Journal of Manufacturing Processes, Vol.54. Paper-based packaging products, due to their excellent sustainable properties are preferred over the glass, plastic, and metal-based packaging solutions. The paper bottle molding process is very new in this category, and the tooling aspect is not well explored. Existing tooling solutions offer certain limitations in the molding process such as clogging of channels, low open-area fraction, low fatigue life, and longer cycle times. With the utilization of additive manufacturing techniques, the tooling can not only be made more economical and produced in shorter time duration but also more efficient. VAT photopolymerization based soft tooling process chain is highlighted and discussed in this work. Design of micro-features and their fabrication is carried out using UV light mask projection method. A characterization approach for precision manufacturing of micro-features using X-ray Computed Tomography is also discussed. Validation of the soft tooling process chain and its effectiveness against the conventional tools is presented and discussed in this work. It is shown that the proposed soft tooling process chain for the manufacturing of molds for paper bottle production is a better performing and cheaper alternative to existing solutions implemented in industry.

NANO-SCIENCE Using Micro- and Nanofibrillated Cellulose as a Means to Reduce Weight of Paper Products: A Review, Franklin Zambrano et al, BioResources, Vol.15(2). Based on publications related to the use of micro- and nanofibrillated cellulose (MNFC) in papermaking applications, three sets of parameters (intrinsic and extrinsic variables, furnish composition, and degree of dispersion) were proposed. This holistic approach intends to facilitate understanding and manipulation of the main factors describing the colloidal behavior in systems comprising of MNFC, pulp fibers, and additives, which directly impact paper product performance. A preliminary techno-economic assessment showed that cost reductions driven by the addition of MNFC in paper furnishes could be as high as USD 149 per ton of fiber (up to 20% fiber reduction without adverse effects on paper's strength) depending on the cost of papermaking fibers. It was also determined that better performance in terms of strength development associated with a higher degree of MNFC fibrillation offset its high manufacturing cost. However, there is a limit from which additional fibrillation does not seem to contribute to further strength gains that can justify the increasing production cost. Further research is needed regarding raw materials, degree of fibrillation, and combination with polyelectrolytes to further explore the potential of MNFC for the reduction of weight of paper products.

A comprehensive study on nanocelluloses in papermaking: the influence of common additives on filler retention and paper strength, Ana F. Lourenรงo et al, Cellulose (2020), online. Nanocelluloses are being explored and produced at an impressively increasing pace. Due to their good characteristics as reinforcement agent, their application in the most diverse fields has proven to be very beneficial. Their use in papermaking has been investigated in several studies, but the industrial implementation is still in a preliminary stage. In the present study, the influence of nanocelluloses, produced by four different treatments (mechanical, enzymatic hydrolysis, TEMPO-mediated oxidation and carboxymethylation) in the properties of filler-containing laboratory handsheets was assessed. Furthermore, five series produced with different additives, among internal strength and sizing agents as well as a retention agent, allowed to

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Technical Abstracts

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

investigate the interactions between the common additives used in paper production and nanocelluloses. It was found that the different properties of the studied nanocelluloses led to very different interactions with the paper components. In this sense, by properly selecting the furnish to use (in terms of nanocellulose typology and presence or absence of each additive), high improvements of filler retention and dry and wet--web strength, as well as reduced surface roughness and water penetration, could be achieved.

Lignocellulosic nanofibers for the reinforcement of brown line paper in industrial water systems, Quim TarrĂŠs et al, Cellulose (2020), online. The addition of nanofibrillated cellulose in paper production requires attention to its dispersion and retention during the paper forming process, and this is commonly facilitated by the use of retention agents. The performance of retention agents, which commonly have a cationic charge, is affected by the presence of dissolved and colloidal substances in the process water. In the process of paper production at an industrial level, especially when using recycled paper, there are a large amount of dissolved and colloidal substances in the water. A high proportion of these substances are negatively charged and are commonly referred to as anionic trash. Its presence increases the conductivity and charge density of the water, and this has a negative influence on the retention of cellulose nanofibers. In brown line paper production, some fibers have already been refined in at least one previous papermaking cycle. In this sense, recycled fibers have a reduced capacity to benefit from refining as they have suffered morphological damage. On the other hand, the addition of lignocellulosic nanofibers in the production of brown line paper has been found helpful to improve its properties and extend its lifespan. In this work the influence on the retention of nanofibers of different anionic trash levels in the water has been evaluated.

The results showed its viability as a reinforcing agent in waters with high anionic trash content, through the addition of an anionic trash catching system.

Design and Synthesis of Fluorescent Nanocelluloses for Sensing and Bioimaging Applications, Prof. Zhao Zhang et al, ChemPlusChem, Vol.85(3). Recent materials research based on fluorescent nanocelluloses (NCs) used in the field of sensing and bioimaging is reviewed. Many designed morphologies have been reported, such as nanoparticles, fibers, nanopapers, hydrogels and aerogels, that have been produced by physical or chemical methods. In the field of sensing and bioimaging, these studies have involved, but not been limited to, special optical properties including fluorescence, longÇŚ lived luminescence, polarized light, and/or aggregationÇŚinduced emission. The fluorescence sensing platforms can be categorized according to stimuli such as pH and temperature, as well as the presence of toxic compounds, and anions and metal cations.

In addition, NCs exhibit unique low toxicity, good biocompatibility, biodegradability and cell membrane penetration, and can be modified into fluorescent nanoprobes for in vivo imaging and tracing. As an excellent platform for fluorescent sensing and bioimaging, NCs are bound to be increasingly studied and widely applied in the field of production and life sciences.

NOVEL PRODUCTS Greaseproof Paper Products: A Review Emphasizing Ecofriendly Approaches, Martin A. Hubbe & Przem Pruszynski, BioResources, Vol.15(1). A cost-effective, ecofriendly, and health-promoting packaging system that prevents the passage of greases and oils would fulfill an urgent need. This review discusses what is known about the highly divergent technological paths that have been studied to achieve these objectives. Before the emergence of plastic films, the paper industry addressed these objectives in two ways, by parchmentizing and by high levels of refining of the fibers. Parchmentizing means

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Technical Abstracts

PAPERmaking! g FROM THE PUBLISHERS OF PAP PER TECHNOLOGY INTERNATIONAL

Volume 6, Number 1, 2020

passing the paper through a bath of concentrated sulfuric acid, followed by rinsing out the acid and drying the sheet. Though both parchmentized paper and highly refined greaseproof paper products are still made, they have been substantially displaced by oilrepellent fluorocarbon treatments of paper. The fluorocarbon treatments have allowed papermakers to achieve greaseproof properties with ordinary paper machine equipment at ordinary refining levels and without a need to immerse the paper in strong acid. Now, however, due to environmental concerns and regulations, the paper industry needs more options. Some promising directions in published research include advances in chemistry, superoleophobic surfaces, nanocellulose films, and systems to protect nanocellulose films from the effects of moisture.

Magnetic paper from sugarcane bagasse fibers modified with cobalt ferrite nanoparticles, Oscar H. PiĂąeres et al, Cellulose, Vol.27. Magnetic paper sheets were prepared from bleached sugarcane bagasse fibers and cobalt ferrite nanoparticles by lumen loading method. Sugarcane bagasse is an important fibrous raw material widely used worldwide for papermaking, whereas cobalt ferrite nanoparticles is an appropriate material for fibers modification given their magnetic properties. Cobalt ferrite nanoparticles were synthetized by coprecipitation method and coated with silica by hydrolysis and condensation of tetraethyl orthosilicate (TEOS) molecules. Then, silica coated magnetic nanoparticles were functionalized with polyethylenimine (PEI), as retention aid, by electrostatic bonding. It was observed that the loading degree of magnetic fibers depends on nanoparticles concentration and PEI dosage, which was determined by thermogravimetric analysis (TGA). Scanning electron microscope (SEM) shows the deposition of coated nanoparticles on the surface and into macropores of fibers. All samples exhibited ferromagnetic behavior. The coercivity values of magnetic fibers are higher than 0.2 kOe. This indicates that these fibers could be used to produce paper for magnetic recording purposes. Magnetic papers with 10 and 20% of modified fibers were manufactured. Brightness and tensile index of papers were decreased with the rise of loading degree. CIEL*a*b analysis shows the color differences between unmodified and modified papers.

Chitosan-modified nitrocellulose membrane for paper-based point-of-care testing, Rui Hua Tang et al, Cellulose, Vol.27. Green/sustainable cellulose paper-based platforms at point-of-care testing have received much interest in biomedical fields at resource-limited settings. In such platforms, biomolecules would have to be immobilized onto paper substrate to achieve detection. Therefore, effective molecule immobilization is critical for the performance of paper-based testing, especially the detection sensitivity.

Although various methods have been developed to improve the detection sensitivity, the immobilization capacity of biomolecules has not been considered yet. In this study, we developed a facile method for modifying paper materials by incorporating chitosan into NC membrane, which has positive effect on the pore size, porosity, and surface groups of NC membrane, hence, enhancing the immobilization capacity of biomolecules on paper substrate. We demonstrated the effectiveness of the above mentioned approach by using nucleic acid lateral flow assay (NALFAs) as a model paper-based platform; in comparison with the unmodified NALFAs, the results showed ten-fold increase in the detection sensitivity for HBV. We envision that this facile modification method will have a great potential for developing other highly sensitive paper-based detecting platforms.

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Correlation between the concentration and morphology of copper microparticles and their biocidal effect on paper sheets, P. Contreras et al, Cellulose (2020), online.

In this study, different methods for incorporating mixed or laminar copper microparticles (CuMPs) during papermaking were evaluated to determine the optimum paper-making process and correlate particle concentration and shape with antimicrobial activity. The addition of CuMPs during the disintegration of dry pulp stage was observed to produce a paper with uniformly distributed CuMPs, as determined through optical microscopy and UV–Vis spectroscopy analyses by measuring absorbance spectra in different areas of papers. Determination of two indices related to the concentration and distribution of copper will allow to predict the copper content in other papers. CuMP-paper samples were evaluated for structural, optical, and mechanical strength properties according to paper industry standards. Quantitative analyses by atomic absorption showed that between 24 and 39% of CuMPs were embedded in the paper fibre, independent of particle type.

Finally, antibacterial activity analyses were performed according to ISO 20645 and ISO 20743. The results showed that papers with 0.30 g of incorporated CuMPs have antimicrobial activity, independent of particle morphology, with effects observed towards Gram (+) and Gram (−) bacteria and fungus. Furthermore, the evaluation of antimicrobial activity at different times of exposure to the microorganisms showed differences in effects that were dependent on the shape of the CuMPs incorporated into paper, where laminar particles exerted a sufficient effect, while no or a slight effect was observed for mixed CuMPs against Aspergillus niger.

Facile Fabrication of Transparent Paper with Tunable Wettability for Use in Biodegradable Substrate, Guodong Li et al, Sustainable Chem. Eng., Vol.8(5).

Transparent paper with excellent optical transmittance and mechanical stability shows potential for use in diverse applications as a substrate. Here, we reported a novel alkyd resin-impregnated cellulose transparent (ARICT) paper that exhibited good flexibility, adequate biodegradability, easy scale-up, and tailorable wettability. As the concentration of alkyd resin increased (5–15 wt %), the optical transmission of the cellulose paper increased from 70.7% to 93.5% at 550 nm, and its water contact angle increased from 9° to 91°. Furthermore, impregnating the cellulose paper with alkyd resin increased the surface smoothness, thermal stability, and toughness of the paper. After poly(3,4ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT:PSS) was coated on one side of the ARICT paper, a flexible single-sided conductive paper with high conductivity was obtained, while the other side retained high insulativity, suggesting that the ARICT paper was a promising substrate for the fabrication of a flexible electrode. Finally, the ecofriendly biodegradability was verified by subjecting the ARICT paper to fungal degradation over time. This study developed a new method for the fabrication of flexible and biodegradable substrates, enabling the development of disposable electronics.

PACKAGING TECHNOLOGY Improving sizing performance of middle layer of liquid packaging board containing high-yield pulp, Fangdong Zhang et al, Cellulose (2020), online. As the important part of liquid packaging board, the middle layer is generally produced from a mixed pulp furnish by unbleached softwood kraft pulp and high-yield pulp (HYP). However, the addition of HYP would bring unsatisfactory properties (e.g. hydrophilicity) to liquid packaging board.

Herein, in this study, the sizing performance of middle layer of liquid packaging board was evaluated by varying the kraft pulp to HYP ratios of middle layer, the dosage of sizing agent and cationic additives etc. It showed that the edge penetration value and Cobb value of middle layer illustrated a better liquid repellence with the addition of sizing agent.

The improved sizing performance of the middle layer of liquid packaging board can be

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ascribed to the excellent performance of the added cationic additive (polyethyleneimine (PEI), alums) for trapping anionic trash via neutralization/flocculation effects. In addition, a binary cationic additive system (Al2(SO4)3-PEI) was proposed to study the improvement on the sizing performance. It was found that a desirable liquid repellence ability can be successfully achieved at a binary additive system containing 1.5% of Al2(SO4)3 and 0.2% of PEI, even when dosage of rosin sizing agent was reduced to 0.5%. The study put forwards a practical approach to improve the sizing performance, especially the liquid repellence ability of liquid packaging board when containing HYP. Fabricating bio-active packing material made from alkali-steam exploded agro-waste using natural colorants, V. K. Nathan et al, International Journal of Environmental Science and Technology, Vol.17. In this paper, effect of alkali-steam explosion pretreatment on various agro-waste raw materials was evaluated for enhancing the quality of recycled paper. The alkali-steam explosion had a minimum cellulose reduction in the case of sugarcane bagasse (3.8 ± 0.21) and arecanut fibers (4.5 ± 0.83%) and identified as a good fiber sources for paper making in terms of strength and final quality of recycled papers. X-ray diffraction pattern study exhibited that there was an enhanced intensity of cellulose content. Coloring on recycled paper with natural pigments could be used as a packing material with bactericidal activity. This forms the first report on the application of stable pigments for value addition in paper industry which increases the marketability of recycled paper.

An analysis of the influence of hand hole and ventilation hole design on compressive strength of corrugated fiberboard boxes by an artificial neural network model, Tita Archaviboonyobul et al, Packaging Technology and Science, Vol.33(4-5).

This research aimed at developing a highǦperforming corrugated fiberboard box compression strength prediction model and to analyze the influences of ventilation and hand hole designs for these containers on the box compression test (BCT) by applying artificial neural network (ANN) modeling. The input variables considered in this study are composed of nine parameters including box dimension as well as shapes, sizes, positions, and locations of ventilations and hand holes of a regular slotted container (RSC, FEFCO 0201). Back propagation algorithms (BPNs) of ANN models were developed from 970 BCT testing data points (single wall boards, C flute, 205/112/205 g/m 2). Tested data was randomly broken into three groups for the model development as 80:10:10 for the training set, testing set, and validating set. According to the analysis performed, a BPN 9Ǧ13Ǧ1 model reflected the highest prediction performance with R2 = 0.97. According to the analysis, BCT was significantly affected by the hand hole location followed by the geometrical dimensions of the box (height, length, and width) and the ventilation factors (shape, number, and location) in that order. Hand holes at the top flaps caused a lower BCT reduction compared with those at the vertical locations of the box. Slight changes to the eliminated board area for both hand holes and ventilation (±5%) contributed to less BCT reduction compared with its locations and shapes. Interestingly, increasing the box height significantly increased the BCT, and this was found to be limited only to shorter boxes fabricated from a high stiffness corrugated board.

Deformation and compressive strength of corrugated cartons under different indentation shapes: Experimental and simulation study, Guifen Gong et al, Packaging Technology and Science (2020), online. A new method to enhance the compressive strength of corrugated cartons is proposed in this study. The work aims to carry out compression tests on the corrugated carton to analyze the deformation and compressive capacity of the carton under the indentation condition of different shapes.

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First, compression tests are carried out on nonindentation cartons, oneǦline indentation cartons, unclosed rhombus indentation cartons, rhombus indentation cartons, and crossǦ indentation cartons to record their maximum compressive force. Second, by comparing the deformation of different cartons, it is found that rhombus indentation and crossǦindentation have the greatest influence on the compressive strength of cartons. Rhombus indentation will enhance the compressive strength of the carton, while crossǦindentation will reduce it.

Third, ANSYS Workbench is used to analyze the buckling of cartons, and the maximum compressive force of nonindentation cartons and rhombus indentation cartons is obtained.

Finally, through the comparison of the finite element method and experiments, it is concluded that rhombus indentation can improve the compressive strength of cartons, which is of great significance to the industrial production of cartons.

PAPER CHEMISTRY Self-assembly of Alkyl Chains of Fatty Acids in Papermaking Systems: A Review of Related Pitch Issues, Hydrophobic Sizing, and pH Effects, Martin A. Hubbe et al, BioResources, Vol.15(2). This review article considers the role of fatty acids and the mutual association of their long-chain (e.g. C18) alkyl and alkenyl groups in some important aspects of papermaking. In particular, published findings suggest that interactions involving fatty acids present as condensed monolayer films can play a controlling role in pitch deposition problems. Self-association among the tails of fatty acids and their soaps also helps to explain some puzzling aspects of hydrophobic sizing of paper. When fatty acids and their soaps are present as monolayers in papermaking systems, the pH values associated with their dissociation, i.e. their pKa values, tend to be strongly shifted. Mutual association also appears to favor non-equilibrium multilayer structures that are tacky and insoluble, possibly serving as a nucleus for deposition of wood extractives, such, as resins and triglyceride fats, in pulp and paper systems.

Paper fillers innovations: From design of particles to preparing filler composites, Shunxi Song et al, BioResources. Vol.15(2). The increase of filler content in paper is an effective way to reduce production costs and to promote the market competitiveness of paper mills. A shift from natural fillers to synthetic fillers has enabled improvements in the critical properties of paper. Meanwhile, innovations from single particles of filler to filler composites has made it possible to increase the filler content of paper. Among various filler innovations, the design of fiber/filler composites has aroused general attention from industry and academic researchers. However, concerns related to the cost and recyclability of composite fillers remain to be addressed.

Studies on ASA emulsion stabilized with anionic polyvinylamine and its evaluation for sizing of different types of paper furnishes, Ashish Kumarab et al, Colloid and Interface Science Communications, Vol.34. Low stability of cationic starch (CS) stabilized alkenyl succinic anhydride (ASA) emulsion is the main drawback of ASA sizing of paper to impart hydrophobicity. Present communication deals with the study of anionic polyvinylamine (APVAm) stabilized ASA emulsion at different process conditions viz. pH, temperature and pulps viz. mixed hardwood (MHW), bagasse (BBS), recycled (RCL) & fillers. APVAm stabilized ASA emulsion was found to be stable at higher pH and temperature. Sizing was better with BBS pulp followed by RCL and MHW pulps. It was evident from the crystallinity ratios and hydrogen bond energy that BBS pulp had the maximum amorphous region that was translated into lesser chemical requirement to attain same sizing followed by RCL and MHW pulps. The better sizing behaviour with lesser dosage of APVAm stabilized ASA emulsion was observed with unfilled and talc filled paper as compared to ground calcium carbonate and precipitated calcium carbonate filled paper.

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Chemical Characterization and Enzymatic Control of Stickies in Kraft Paper Production, Lourdes Ballinas-Casarrubias et al, Polymers, 12(1). Paper recycling has increased in recent years. A principal consequence of this process is the problem of addressing some polymeric components known as stickies. A deep characterization of stickies sampled over one year in a recycled paper industry in México was performed.

Based on their chemical structure, an enzymatic assay was performed using lipases.

Compounds found in stickies by Fourier-transform infrared spectrometry were poly (butylacrylate), dioctyl phthalate, poly (vinyl-acetate), and poly (vinyl-acrylate). Pulp with 4% (w/w) consistency and pH = 6.2 was sampled directly from the mill once macrostickies were removed. Stickies were quantified by counting the tacky macrostructures in the liquid fraction of the pulp using a Neubauer chamber before the paper was made, and they were analyzed with rhodamine dye and a UV lamp. Of the two commercial enzymes evaluated, the best treatment condition used Lipase 30 G (Specialty Enzymes & Biotechnologies Co®, Chino, CA, USA) at a concentration of 0.44 g/L, which decreased 35.59% of stickies.

SebOil DG (Specialty Enzymes & Biotechnologies®) showed a stickies reduction of 21.5% when used at a concentration of 0.33 g/L. Stickies in kraft paper processes were actively controlled by the action of lipases, and future research should focus on how this enzyme recognizes its substrate and should apply synthetic biology to improve lipase specificity.

PAPER PROCESS Dewatering of foam-laid and water-laid structures and the formed web properties, Jani Lehmonen et al, Cellulose, Vol.27. The use of aqueous foams as a carrier fluid for pulp fibers instead of water has re-emerged in the paper and board industry in recent years. In foam forming, a surfactant is needed to reduce the surface tension of the carrier liquid and to create foam as a process fluid and flowing medium. This presents the following questions: (1) How do the water forming and foam forming processes differ? (2) How do the obtained wet/dry fibre sheets differ after forming and after wet pressing? (3) Which differences in the process behavior and sheet properties are due to the surfactant, and which are due to the presence of air bubbles in the flowing medium? The answers to these questions were sought by using an experimental academic approach and by applying a special dynamic vacuum assisted sheet former. Although foams are much more viscous than water, dewatering times were found to be approximately equal in water and foam forming at higher vacuum levels. The hydrodynamic resistance of sheet was approximately constant during water forming, while in foam forming resistance was initially even smaller than in water forming but it increased with time, being substantially higher at the end of the forming process. In certain cases, surfactant alone was found to have a similar, albeit often lower, effect on the sheet properties of foam. Surfactant improved sheet dryness (both after forming and wet pressing), lowered density, and lowered strength properties also in water forming. Foam, on the other hand, had a crucial effect particularly on certain structural properties such as formation and porosity. The difference between water and foam-laid sheets typically reduced in line with higher wet pressing pressure. This suggests that the role of surface tension and foam bubbles in controlling interfiber contact is overridden by wet pressing pressure. Thus applying foam as a carrier fluid has characteristic effects both on the papermaking process and the end product properties. The main features of foam forming can be explained by the chemical effects caused by the surfactant, and the structural effects caused by the foam bubbles.

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Enhancement of drying of paper with phase change material: A numerical study, Alireza Mahdavi Nejad, International Journal of Heat and Mass Transfer, Vol.149.

This work numerically investigates the transport characteristics associated with the drying process of paper in the presence of a phase change material (PCM). The presence of PCM is studied in two different configurations: a layer of PCM embedded in the middle of paper and the PCM particles dispersed uniformly within the paper. This unique concept offers a new approach to paper drying by utilizing the latent-heat of fusion associated with the PCM, favorably impacting the energy efficiency of the drying process. The results indicate that the PCM acts as a heat source and a heat sink throughout the drying process, enhancing the drying rate. This study also includes the presence of an infrared emitter within the drying process. The corresponding absorption coefficient of PCM is measured experimentally. This paper is not concerned with the impact of presence of PCM on paper sheet properties. The proposed operating conditions and configuration presented here are solely for the purpose of illustration of the concept of drying in the presence of PCM. A sampling-based stochastic optimization for a boiler process in a pulp industry, Gustavo Matheus de Almeida et al, Korean Journal of Chemical Engineering, Vol.37(4). Our Aim was to find the stochastic optimal solution for a boiler process in order to maximize steam generation while complying with pollutant emissions regulations. For a simulation base-model, support vector regression (SVR) is employed to present a general discrete-time dynamical system of a boiler, and a stochastic optimization was performed to take inherent process uncertainties into account. To generate a stochastic optimization problem, sample average approximation (SAA) based on Monte-Carlo sampling was introduced due to the properties of a SVR. Moreover, a gradient free-based particle swarm optimization (PSO) technique was applied to find the optimal parameters of SVR and investigate the stochastic optimal solution for the boiler process. The results show that the stochastic optimal solution provides almost 2% more steam generation under uncertainties: this indicates that the stochastic optimal solution provides more realistic results compared to the deterministic approach. The proposed methodology can be applied straightforwardly to black box models, or when the use of gradient-based optimization solvers is restricted.

Multidimensional Interpolation Decoupling Strategy for CD Basis Weight of Papermaking Process, Wenjuan Shan & Bing Liu, Symmetry, 12(1). With a focus on the multivariable coupling characteristics in a cross-directional (CD) basis weight control system, we study the coupling characteristics of a CD control system and decoupling control, and we propose a novel multivariable interpolation decoupling control strategy and a real-time decomposition algorithm in this paper. Based on a model of the CD basis weight profile, a system non-square interaction matrix of high-dimensional data is analyzed by experimental studies and numerical simulation. Along the diagonal of the interaction matrix, the matrix block method is adopted to reduce the system dimension and convert it into a square system. A multivariable control system with high dimensionality is divided into several subsystems. For the high-dimensional Toeplitz symmetric subsystem with small-scale coupling characteristics, an interpolation decoupling algorithm is proposed.

Then, a decoupling compensator with the structure of a symmetric Toeplitz matrix was obtained. Compared with the conventional diagonal decoupling matrix, the branch number of the new decoupling network is reduced from 2408 to 186, which realizes the fast decoupling of multivariable systems. The results were even better when we used a double size interaction matrix obtained by interpolation between actual values. By designing the diagonalized controller for the new decoupled system, a decouped CD control system for

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corrugated paper with a basis weight of 133 g/m2 was implemented in an actual project in a paper mill. View Full-Text PRINTING Effect of Papermaking Conditions on the Ink Absorption and Overprint Accuracy of Paper, Yuanfeng Dong et al, Bioresources, Vol.15(1). The ink-absorption capacity is an important factor for evaluating the printing quality of paper. In this study, the effects of different parameters of papermaking on the ink-absorption capacity of paper were investigated. The results showed that hardwood pulp exhibited better performance in increasing the absorptivity of paper compared with softwood pulp. When the content of hardwood pulp in paper was increased from 0% to 100%, the ink mark length decreased from 5.1 cm to 4.3 cm. Furthermore, a basis weight change from 100 g/m2 to 60 g/m2 increased the ink-absorption capacity, as revealed by a decrease of the ink mark length from 4.8 cm to 4.4 cm. Both sizing agent and beating degree affected the ink-absorption performance of the paper. For example, a shorter ink mark length of 5.1 cm was obtained at a low beating degree of 5000 r compared with that of 5.1 cm at 15000 r.

A New Kind of Nonconventional Luminogen Based on Aliphatic Polyhydroxyurethane and Its Potential Application in Ink-Free Anticounterfeiting Printing, Zihao Feng et al, Appl. Mater. Interfaces, Vol.12(9). Organic luminogens have extensive applications due to their unique photophysical properties. In recent years, nonconjugated organic luminogens, in contrast to traditional conjugated luminogens, have gained much attention because of their facile preparation, environmental friendliness, and biocompatibility. In this study, a new kind of nonconventional luminogen based on dynamic covalent cross-linked polyhydroxyurethane is reported for the first time. The new luminogen not only exhibits intrinsic strong fluorescent emission in the solid state but also possesses high mechanical properties along with good shape memory and self-healing properties. In addition, the new luminogens are synthesized from aliphatic polyfunctional cyclic carbonate and amines via a much more straightforward method, avoiding the use of toxic isocyanates. Investigations indicated that the intrinsic luminescence of the resultant luminogens was induced by the cross-linking of polymer chains and could be well tuned by controlling the degree of cross-linking. By taking advantage of the unique characteristics of the resultant polymer luminogens, we further developed a facile method, named â&#x20AC;&#x153;lightmediated ink-free screen printingâ&#x20AC;?, for anticounterfeiting paper fabrication. Different from traditional ink-based printing technology, the new method used UV-light instead of expensive security ink to encode anticounterfeiting information on natural cellulose paper.

The anticounterfeiting information is stable under various wet conditions, showing promising applications in the fast-growing counterfeiting of pharmaceuticals, packaging, and the food industry.

PULP / PULPING Ecofriendly and Innovative Processing of Hemp Hurds Fibers for Tissue and Towel Paper, Ved Naithani et al, BioResources, Vol.15(1). An innovative approach for preparing hemp fibers from hemp hurds for use in tissue and towel grades of paper is described. Hemp hurds are a low value by-product of industrial hemp processing that are generally used for animal bed litter. Tissue paper was fabricated from hemp hurd fibers by following three pulping processes: autohydrolysis (hydrothermal), sodium carbonate-based defibration, and high yield kraft pulping, and benchmarked against hardwood pulp. To meet industrial standards, hardwood and hemp pulp fibers were mixed at a dry mass ratio of 75:25, from which tissue paper sheets were prepared. Desirable tissue paper properties, such as water absorption, burst resistance, softness, and tensile strength (dry

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and wet), were measured and compared. Characterization of morphological and chemical properties of tissue handsheets was conducted with SEM and time-of-flight-secondary ion mass spectrometry (ToF-SIMS). The combined kraft pulped hardwood and autohydrolyzed hemp pulp fibers displayed improvements in tensile index, burst resistance, and softness of tissue handsheets compared to only kraft hardwood pulp handsheets without adversely impacting water absorption. Hardwood fibers showed a sparse distribution of surface lignin compared to hemp fibers using the same defibration. This technology can lead to a variety of eco-friendly tissue paper products that are not only highly energy efficient, but avoid harsh chemical processing.

Effect of hydrogen peroxide bleaching on anionic groups and structures of sulfonated chemo-mechanical pulp fibers, Mingfu Lia et al, Colloids and Surfaces A: Physicochemical and Engineering Aspects, Vol.585. The properties of the chemomechanical pulp were determined by the position and quantity of anionic groups in the pulp fibers. In this study, the effects of anion group content and structure in sulfonated mulberry stem chemo-mechanical pulp (SCMP) were investigated during the hydrogen peroxide (H2O2) bleaching process. Surface morphology and anion group structure of the pulp fibers were analyzed by scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and gas chromatography-mass spectrometry (GCMS). The results indicate that the sulfonic group content in bleached pulp decreases with the concentration of H2O2 to a minimum content of 71.53 μmol g−1, which is reduced by 22.68% in comparison to the unbleached pulp content of 92.51 μmol g−1. The content of carboxyl groups in pulp first increases and then decreases with the concentration of H2O2. The maximum carboxyl group content is 164.79 μmol g−1, which is increased by 53.97% compared with unbleached pulp at 107.03 μmol g−1. The total anion groups content of SCMP first increases and then decreases with the concentration of H2O2. FTIR and XPS analysis show that the content of anion groups on the surface of the pulp fibers increases slightly after H2O2 bleaching. GCMS analysis demonstrates that the content of uronic acid increases after H2O2 bleaching and the order of increase is 4-O-MeGlcA > GlcA > GalA. The contents of sulfonic acid group, total anion groups (TAGs) and surface anion groups (SAGs) of bleached pulp increase because of the hydroxyl group oxidation, terminal group reduction, methyl esterification of pectin and decomposition of polyxylose, resulting in the formation of new carboxyl groups and more uronic acid. This study reveals the mechanism of the effect of hydrogen peroxide bleaching on the anionic groups in the SCMP pulp, which is conducive to the development of bleaching technology for high yields of mulberry stem pulp.

MCDM approach for selection of raw material in pulp and papermaking industry, Meenu Singh et al, Materials and Manufacturing Processes, Vol.35(3). Selection of a suitable fibrous raw material for the pulp and papermaking industries is a tedious process involving a lot of experimental procedures. This process can be reduced to some extent through computer-based simulation tools and treating the problem as a multi-criteria decision making (MCDM) problem. In the present study, selection of fibrous raw material is treated as an MCDM problem where chemical, morphological and physical properties of the fibers are considered as different criteria and study is done in context of Indian Pulp and Paper Mills. TOPSIS, its fuzzy variant (FTOPSIS) and its modified variant (MTOPSIS) are employed to identify the suitable selection of fibers. The results obtained by these methods when discussed with experts indicate that MCDM tools like TOPSIS (and its variants) can be an attractive alternative for simulation-based selection of fibrous raw material for pulp and paper industries.

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RECYCLING The effect of the addition of primary fibers on the papermaking ability of wastepaper, Aleksandra Niska & Edyta Malachowska, Annals of Warsaw University of Life Sciences - Forestry and Wood Technology, No.108, 2019:104-110. The effect of the addition of primary fibers on the papermaking ability of wastepaper. The rapid increase in paper production and consumption at the end of the 20thcentury contributed to the increasing difficulties connected with assurance of required resources base for paper industry and the utilization of the growing amount of paper waste. The wastepaper salvage and application of secondary pulps for paper production make a significant contribution to solving these issues, and these activities are justified based on ecology and economy. It must be said, however, that the addition of certain amount of primary fibers is necessary to ensure strength and others usable properties of produced paper. The authors have set themselves the goal of the examination of primary fibers addition on papermaking ability of wastepaper. Studies have shown that the addition of primary fibers to wastepaper has a positive impact on all examined strength properties of paper.

Green ecofriendly bio-deinking of mixed office waste paper using various enzymes from Rhizopus microsporus AH3: efficiency and characteristics, Mohamed Sayed Hasanin et al, Cellulose (2020), online. Mixed office waste paper (MOWP) is a low cost, high quality and easily collected fiber source for the papermaking industry. Unfortunately, limits in the application of traditional deinking are related to the negative environmental impacts of using chemicals during the deinking process. Hence, enzymatic deinking has received growing attention in the last decade. This study investigates the effect of using the effective enzymes produced from Rhizopus microspores AH3 which is grown on watermelon peel waste (WPW) extract, as a bio-deinking method in the deinking of MOWP, which is difficult to recycle because of their ink type and printing process. The methodology involves preparation of samples, impregnation with water, enzymatic treatment, washing, papermaking, evaluation of the produced paper sheets. The evaluation includes determination of the optical and mechanical properties as well as topographic investigation via scanning electron microscope of produced paper sheets. The results showed that there is an improvement in both optical and mechanical properties of all paper sheets produced in this study. The best enhancement was for medium B30 which was extracted by boiling of WPW for 30 min. This treatment gave high enhancement because of the effect of the produced enzymes from Rhizopus microspores AH3, where cellulase, xylanase, lignin peroxidase, poly phenol oxidase and laccase were 1.62, 1.49, 1.38, 1.2 and 1.5 U/ml, respectively. Moreover, the tensile strain (maximum load) increased by about 77% as well as the brightness percentage achieved about 86.78% and the deinking ability was increased approximately 16%.

Environmental issues of pulp bleaching and prospects of peracetic acid pulp bleaching: A review, Nirmal Sharmaab et al, Journal of Cleaner Production, Vol.256.

To meet the demand of pulp and paper as well as the environmental legislation the pulp production with eco-friendly approach is desired. This paper presented the state of affairs of Indian and world pulp and paper industry. It also reviewed the discharge of toxic substances from pulp bleaching process and the alternatives for reduction of these toxic substances from pulp bleaching process. The pulp and paper industry is continually changing the bleaching process to minimize the use of chlorine and chlorine based compounds in order to satisfy regulatory and market demands. Imminent to have the minimum impact on environment from bleach plant peracetic acid is the prospective candidate. Use of peracetic acid is a promising technology as it has the capability to reduce/replace chlorine based compounds from pulp bleaching process. This paper

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reviewed the peracetic acid pulp bleaching and its impact on pulp properties and presented the eco-friendly bleaching process for mixed hardwood.

Paper Fillers Innovations: From Design of Particles to Preparing Filler Composites, Design and Fabrication of Paper Recycling Unit, Aditya Vinod Pillai et al, International Journal of Mechanical Engineering and Technology, Vol.11(2). In any big institution, especially educational institutions like schools or colleges, generation of large quantity of waste papers is quite apparent. And effective use of recycled paper is also possible (craft papers, registers etc). So, instead of disposing off the waste papers into trash, recycling them makes sense. This not only helps the institute in cost saving but will also ensure its contribution towards the protection of the environment. Designing manually operated small-scaled paper recycling plant, which can be used in schools and colleges, ensures that a cheap and non-complex method of production of paper product is guaranteed. Accordingly design of the machine unit has been prepared with all necessary component specifications.

Synthesis of chitosan composite microspheres and their application for the removal of stickies in the recycled paper, Yuekai Geng et al, Journal of Polymer Research Vol.27, Article No.97. Stickies deriving from the recycled paper had multiple deleterious effects on the paper chemicals, machine run-nability and paper equality. The aim of this study was to synthesize citosan composite microspheres and remove stickies in the recycled paper by microspheres. Citosan-montmorillonite and chitosan-ferroferric oxide composite microspheres were prepared by emulsion cross-linking method. The surface morphology of microparticels was analyzed by Digital microscope (DM) and Scanning electron microscope (SEM). The removal effects of composite microspheres and talc on stickies were compared. It was found that CS-MMT microspheres had excellent thermal stability than chitosan microspheres and CS-Fe3O4 microspheres. The zeta potential of stock increased with the addition of talc,CS-MMT or CS-Fe3O4. Comparing with the plate talc, CS-MMT or CS-Fe3O4 microspheres adsorbed more easily the stickies and removed DCS in the recycled paper. Meanwhile, CS-MMT or CS-Fe3O4 had less negative impact on the strength of paper than talc. It contributed that there was a large number of hydroxyl groups on the surface of composite microspheres. CS-Fe3O4 had magnetic characteristics and the ability of removing Dissolved and Colloidal Substances (DCS) in white water were superior to CS-MMT. TESTING Quantitative aging assessment method for cellulose pressboard based on the interpretation of the dielectric response mechanism, Jiacheng Xie et al, Cellulose (2020), online. Cellulose pressboard is used as a key element in various power equipment insulation structures and determines the operational safety of electric equipment and power systems. This paper aims to increase the application of a pressboard aging assessment method based on frequency domain spectroscopy, a promising nondestructive method for power equipment diagnosis, through in-depth theoretical analysis and accurate data fitting. To achieve this purpose, first, based on classic theoretical models in the field of dielectric physics, a mathematical deduction is proposed to separate each dielectric process in the overlapping frequency band. Second, a novel analysis approach that considers both the pressboard dielectric response and the thermally stimulated current is proposed and demonstrated to be effective in determining the physical meaning of pressboard microscopic dielectric processes. Third, a function model based on a specific microscopic mechanism is established to fit the frequency domain spectra of pressboard samples with different aging degrees. Based on this

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approach, the variations in charge carrier motion characteristics in the frequency domain with increasing pressboard aging degree are clarified. Moreover, the function model provides characteristic parameters that are clearly related to the degree of polymerization of the material, which represents a quantitative method for evaluating the aging degree of cellulose pressboard by indirectly obtaining its frequency response curve.

Instrumentation for Measuring the Wet Frictional Property of Sanitary Pads, Ka-Po Maggie Tang et al, Fibers and Polymers, Vol.21. Women wear sanitary pad for whole day during their menstruation period. They have direct skin contact with it even for sleeping and exercising. The presence of sweat and menstrual blood increases the moisture level and the adhesion of liquid to textile causing sensorial discomfort. This study describes the design and uses of modified Textile Stickiness Measurement System (TSMS) which can characterize the frictional properties of sanitary pads under both dry and wet conditions. The uniqueness of this measurement system is that the wetness level of the pad is adjustable and the surface profile of the contacting object (i.e. Lorica®Soft) does simulate the condition of human skin. Also, it does not have restriction on the type of sanitary pad that can be tested. Among the 12 sanitary pads tested (disposable and reusable types), the frictional force for the disposable sanitary pads is lower than the reusable pads whilst the performance of disposable sanitary pads with nonwoven surface is lower than the one with perforated surface. These can attribute to their liquid transport property and surface feature. For those with better liquid transport property, less water will stay on skin surface and so the adhesion between skin and textiles is lower. For those with protruding fibers on its surface, it reduced the contact area and so the frictional force is lower.

Modelling the impact of crushing on the strength performance of corrugated fibreboard, Mohamad Aiman Jamsari et al, Packaging Technology and Science, Vol.33(4-5). This paper presents different ways of modelling the strength of corrugated fibreboard (CFB) subjected to different levels of preǦcrushing. The strength performance was measured through fourǦpoint bending loading and edge crush test (ECT). The models used in this study were an analytical solution, an equivalent flute model, and detailed flute geometry models that consisted of idealized sine geometry and real geometry.

Deformation and compressive strength of corrugated cartons under different indentation shapes: Experimental and simulation study, Guifen Gong et al, Packaging Science and Technology (2020), online. A new method to enhance the compressive strength of corrugated cartons is proposed in this study. The work aims to carry out compression tests on the corrugated carton to analyze the deformation and compressive capacity of the carton under the indentation condition of different shapes.

First, compression tests are carried out on nonindentation cartons, oneǦline indentation cartons, unclosed rhombus indentation cartons, rhombus indentation cartons, and crossǦ indentation cartons to record their maximum compressive force. Second, by comparing the deformation of different cartons, it is found that rhombus indentation and crossǦindentation have the greatest influence on the compressive strength of cartons. Rhombus indentation will enhance the compressive strength of the carton, while crossǦindentation will reduce it.

Third, ANSYS Workbench is used to analyze the buckling of cartons, and the maximum compressive force of nonindentation cartons and rhombus indentation cartons is obtained.

Finally, through the comparison of the finite element method and experiments, it is concluded that rhombus indentation can improve the compressive strength of cartons, which is of great significance to the industrial production of cartons.

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Cationic polyacrylamide induced flocculation and turbulent dewatering of microalgae on a Britt Dynamic Drainage Jar, Mutah Musa et al, Separation and Purification Technology, Vol.233. Dewatering is one of the major constraints to the large scale production of microalgae biofuels, with many drawbacks in currently deployed technologies. Using an approach similar to papermaking, cationic polyacrylamide (CPAM) based flocculants can stabilize flocs of microalgae under turbulent conditions to achieve effective dewatering of dilute suspensions in high speed filtration systems. The effects of flocculant dosage, stirrer speed (i.e. turbulence) and pH on filtration retention was investigated using a Britt Dynamic Drainage Jar (BDDJ) which simulates a commercial paper machine. The development of a stable floc system that withstood turbulence was achieved through the flocculant’s dual effects of charge neutralization and bridging of the microalgae cells. Retention of microalgae on a 76 μm screen improved from 7% when no flocculant was used to 94% at a flocculant dosage of 10 mg/L of CPAM, stirrer speed of 1200 rpm and pH of 6.5 as optimum conditions. The most significant effects on microalgae retention were that of flocculant dosage; followed by the combined interaction between stirrer speed and flocculant dosage; and that of pH. A key finding is that high retention was obtained under moderately turbulent conditions. This study shows that the paper dewatering technique will be potentially applicable for microalgae preconcentration in the production of biofuels, and further pilot scale studies are recommended.

TISSUE A semiǦquantitative job exposure matrix for dust exposures in Swedish soft tissue paper mills, Richard L. Neitzel et al, American Journal of Industrial Medicine, Vol.63(4). Total paper dust exposure has been associated with respiratory problems among workers in the soft tissue paper industry. However, a comprehensive job exposure matrix (JEM) has not been developed for application to this industry. Our study was intended to address this need and to support further studies of mortality and morbidity in a cohort of Swedish workers from this industry.

Synthesis and Application of a Cationic Polyamine as Yankee Dryer Coating Agent for the Tissue Paper-Making Process, Cesar Valencia et al, Polymers, Vol.12(1).

Tissue paper is of high importance worldwide and, continuously, research is focused on improvements of the softening and durability properties of the paper which depend specifically on the production process. Polyamide-amine-epichlorohydrin (PAE) resins along with release agents are widely used to adhere the paper to the yankee dryer (creping cylinder) in paper manufacture. Nevertheless, these resins are highly cationic and they normally adhere in excess to the paper which negatively affects the creping process and the quality of the paper. For this reason, a low cationic polyamine-epichlorohydrin coating (Polycoat 38®) was synthesized from a diamine supplied by Disproquin S.A.S. and epichlorohydrin. The analysis of the synthesized polymer was carried out by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (1H-NMR). The molecular weight of the polymer was obtained by gel permeation chromatography (GPC), physical-chemical properties such as kinematic viscosity, percentage of solids, density, charge density were measured and compared with a commercial PAE resin (Dispro620®) Thermal stability of the Polycoat 38® and glass transition temperature in presence of a release agent (Disprosol 17®) were also evaluated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), respectively. Finally, a peel adhesion test and an absorption durability assessment were carried out together with the evaluation of the creeping efficiency of the paper by caliber and tensile measurements in a tissue (towel paper) production plant, demonstrating a superior performance in the paper creping process as compared to some commercially available products.

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WASTE TREATMENT NanocelluloseǦEnabled Membranes for Water Purification: Perspectives, Priyanka R. Sharma et al, Advanced Sustainable Systems (2020), online. Membrane technology remains the most energyǦefficient process for removing contaminants (micrometerǦsize particles to angstromǦsize hydrated ions) from water. However, the current membrane technology, involving relatively expensive synthetic materials, is often nonsustainable for the poorest communities in the society. In this article, perspectives are provided on the emerging nanocelluloseǦenabled membrane technology based on nanoscale cellulose fibers that can be extracted from almost any biomass. It is conceivable that nanocellulose membranes developed from inexpensive, abundant, and sustainable resources (such as agriculture residues and underutilized biomass waste) can lower the cost of membrane separation, as these membranes offer the ability to remove a range of pollutants in one step, via size exclusion and/or adsorption. The nanocelluloseǦenabled membrane technology not only may be suitable for tackling global drinking water challenges, but it can also provide a new lowǦcost platform for various pressureǦdriven filtration techniques, such as microfiltration, ultrafiltration, nanofiltration, and reverse osmosis. Some relevant parameters that can control the filtration performance of nanocelluloseǦenabled membranes are comprehensively discussed. A short review of the current state of development for nanocellulose membranes is also provided.

Pulp and Paper Mill Wastewater: Ecotoxicological Effects and Bioremediation Approaches for Environmental Safety, Izharul Haq & Abhay Raj, Bioremediation of Industrial Waste for Environmental Safety, pp.333-356 (Springer). Pulp and paper industry is one of the important industrial sectors in India, which consume huge amount of water in the papermaking process. The final wastewater is often characterized by high color, BOD (biochemical oxygen demand), COD (chemical oxygen demand), AOX (adsorbable organic halides), SS (suspended solids), TDS (total dissolved solids), phenolics, heavy metals, and plant components like lignin, tannin, resin acids, and extractives. Finally, these compounds are reached to aquatic and terrestrial ecosystem and causing serious environmental pollution. The generated wastewaters are treated by conventional biological treatment like activated sludge process (ASP) after primary treatment. Biological treatment of paper mill effluent significantly removes BOD, COD, SS, and also COD, but it is insufficient in removal of lignin and chlorophenols due to its low biodegradability and toxicity. During last few decades, several physical and chemical methods have been developed with the aim to use as pre- and posttreatment method.

However, application of this technology at large scale is costly. Therefore, bioremediation which involve the use of pollutant-specific microorganism for wastewater treatment has been considered as cost-effective and eco-friendly treatment method. Thus, this chapter provides the updated information on paper processing and wastewater generation and their characteristics and toxicity. Processes based on physicochemical and biological methods for the treatment of pulp and paper mill wastewater have been also discussed.

Cationic Polyacrylamide Emulsion with Ultra-high Concentration as a Flocculant for Paper Mill Wastewater Treatment, Kaiji Yang et al, BioResources, Vol.15(2). Cationic polyacrylamide emulsions prepared with ultra-high concentration (CPAME-uhc) have the advantages of fast dissolution, convenient operation, and low transportation cost. In order to further improve the molecular weight, solubility, and temperature/salt resistance of CPAME-uhc, in this study the preparation process of CPAME-uhc was optimized, and the effects of solubilizing agents and functional monomers on solubility and temperature/ salt resistance of CPAME-uhc were evaluated. Finally, the flocculation performance of CPAME-uhc on papermaking wastewater was examined. The results showed that the

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molecular weight of CPAME-uhc can be increased to 14 to 15 million by process optimization, and the solubility of CPAME-uhc can be greatly increased by adding urea and Na2SO4. The temperature/salt resistance of CPAME-uhc can be improved by adding 2 wt% N,N-dimethylacrylamide, 2 wt% N-vinylpyrrolidone, and 5 wt% sodium 2acrylamide-2-methylpropionate, based on the total monomer weight. When CPAME-uhc was added to papermaking wastewater the removal percentages of chemical oxygen demand (COD) and suspended solid (SS) were 95% and 93%, respectively. This study provides a useful reference for the preparation, optimization and application of CPAMEuhc.

Treatment Technologies for Addressing the Removal of Industrial Effluents Affecting the Quality of Ganges River in Eastern Part of Uttar Pradesh, India, Sumedha Shah & Abha Mishra, Combined Application of Physico-Chemical & Microbiological Processes for Industrial Effluent Treatment Plant, pp.29-46 (Springer). India has emerged as a hub for research and development and is ready for escalating to fourth industrial revolution. The fourth level revolves around fusion of technologies for elevating the upcoming manufacturing techniques. Industrialization has helped India to flourish and grow economically among the other developing countries. With all the advantages of increase in industries and production, there comes up the problem of increase in pollutants and contaminants that are discharged untreated. The various sectors of industries in India include textile, cement, mining, food processing, chemical, steel, and dairy. They produce a mixture of toxic and nontoxic pollutants that may or may not be persistent in nature. These pollutants are majorly carcinogenic or become one over their due course of time if not treated. The text focuses on treatment technologies of waste water in the eastern part of Uttar Pradesh, an industrial state in India, where most of the industries are by the side of Ganges River. These industries generate significant amount of waste most likely being chemical and synthetic dyes, heavy metals, and pesticides which are persistent pollutants. The treatment of effluent is essential to stabilize the BOD and COD and reduce presence of heavy metals in river water. The various treatment technologies are used individually or in combination to have effective retaliation and applicability.

Humidity impact on photo-catalytic degradation: Adsorption behavior simulations and catalytic reaction mechanisms for main gaseous pollutants in papermaking industry, Zhifeng Lin et al, Journal of Cleaner Production, Vol.244. To adopt cleaner production technology of photo-catalysis in papermaking industry and improve environmental sustainability, it is essential to understand the impact of ambient humidity on photo-catalytic degradations of gaseous pollutants. This study used TiO2 colloid as catalyst to study the effects of ambient humidity (30â&#x20AC;&#x201C;60%) on the photo-catalytic degradations of formaldehyde (HCHO), benzene (C6H6), and hydrogen sulfide (H2S) generated by papermaking industry. Via adsorption behavior simulations, using density functional theory (DFT) and catalytic reaction mechanisms, the effects of humidity were further investigated. The following results were found: (1) With increasing humidity, the degradation of HCHO was inhibited, because the ambient H2O content exceeded the demand for hydroxyl radicals produced by H2O, which led to competitive adsorption. (2) For C6H6, an optimum humidity of 40% was identified during the degradation process, which could be attributed to the improved catalytic reaction and the subsequent excessive H2O content. (3) For H2S, unlike the negative action for HCHO and the first positive and then negative actions for C6H6, with increasing humidity, the H2S degradation was promoted. This indicated that the large demand for hydroxyl radicals produced by H2O promoted the H2S catalytic reaction. Combining experimental, simulation, and theoretical

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results for these different gaseous pollutants provides sufficient information to understand the impact of humidity on the photo-catalytic oxidation degradation process.

Nanocellulose water treatment membranes and filters: a review, Andreas Mautner, Polymer International (2020), online. This review covers the use of nanocelluloses in water treatment applications with particular focus on membranes and filters made either entirely from (nano)cellulose or in composite approaches. Nanocelluloses are among the emerging materials of this century, having found an abundance of potential applications in the fields of composites, medicine, functional additives or water treatment. Water treatment applications in particular have received significant academic and commercial attention, with a large variety of approaches developed in order to address arguably one of the largest problems that humanity is confronted with in the 21st century: clean water. In this regard, treatment of both potable water and wastewater is of high importance. The reason for the viability of nanocelluloses as base material relies upon their high specific surface area and abundance of OH groups that already exhibit certain attraction toward pollutants carrying ionic structures or dyes and also can be easily modified to significantly increase the affinity of nanocelluloses toward these pollutants. Nanocelluloses in their various forms (cellulose nanocrystals, cellulose nanofibrils, bacterial cellulose) have been applied in water treatment, with membranes and filters (size exclusion, e.g. for nanoparticle filtration, or affinity membranes) as well as adsorbents (e.g. heavy metal ions, dyes, nitrates) being the most studied.

Preparation, characterization, and application of magnetic activated carbon for treatment of biologically treated papermaking wastewater, Zhuqing Feng et al, Science of The Total Environment, Vol.713. In view of the urgent need for tertiary treatment of papermaking wastewater and the difficulty in separating powdered activated carbon (PAC) from water, the magnetic activated carbon (33%-MPAC, 50%-MPAC and 67%-MPAC) were prepared by chemical coprecipitation method for adsorption of biologically treated papermaking wastewater (BTPW). A series of characterization of MPAC and PAC were carried out and show that the content of iron oxides is negatively related to the proportion of micropores in MPAC. The loaded iron oxides is mainly the mixture of magnetite and maghemite, and the maximum saturation magnetization of MPAC can reach 29.68 emu/g. Batch mode experiments were performed, and found that the adsorption effect of MPAC is slightly worse than that of PAC, the adsorption capacity of COD in MPAC can reach about 65 mg/g, and pH = 2 and 10 °C are more favorable for adsorption. The adsorption isotherms and kinetics were well fitted by the Freundlich model and pseudo-second-order kinetic model, respectively. The selective adsorption was studied by using the excitation emission matrix (EEM) fluorescence spectrum and highperformance size exclusion chromatography (HPSEC). It is concluded that all adsorbents are preferred to adsorb humic acid-like substances (HA). And all adsorbents are preferred to adsorb low apparent molecular weight substances (LAMW, AMW < 1500 Da), with the increase of iron oxides content, the phenomenon of MPAC preferentially adsorbed LAMW became less obvious.

Effects of charge density and molecular weight of papermaking sludge-based flocculant on its decolorization efficiencies, Kangying Guo et al, Science of The Total Environment, Vol.723. The charge densities (CD) and molecular weights (MW) of the flocculants are closely related to their application performances, but seldom researches focus on the effects of flocculant CD and MW on decolorization efficiencies.

Herein, a series of flocculants with various CD and MW levels, named as PBF1â&#x20AC;&#x201C;9, were designed and synthesized from papermaking sludge. The physicochemical characteristics

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of the PBF1â&#x20AC;&#x201C;9 were measured by fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), X-ray photoelectron spectroscopy (XPS) and particle charge density analyzer (PCD). The efficiencies of PBF1â&#x20AC;&#x201C;9 were studied in the reactive blue (RB) dye removals by flocculation under different process conditions. The operation costs of the flocculants were evaluated at their optimal dosages. Also, the pHindependences and ion-tolerances of the aforementioned flocculants were studied in terms of the molecular levels. The experimental results exhibited that the flocculants CD or MW values were relevant to their flocculation behaviors and operation costs. CD values played a dominant role in color removal efficiencies and the costs, whereas MW values were critical to the floc structure. The pH or ion-independences of the flocculants were significantly dependent on the CD and MW values. However, some conclusions, conflicted with prior studies, were observed in this work. For instance, flocculant with the highest CD and MW levels was not the most effective one in enduring pH variation and the coexisting ions. The floc properties, including floc size, resistance and recovery ability, were relatively insensitive to flocculant intrinsic CD and MW levels when the flocculants were used at their optimal dosages. Furthermore, the possible relevance between CD or MW levels and the flocculation mechanisms have been proposed in this work. Exploring the effects of flocculants CD and MW levels could precisely control the flocculant characteristics to achieve satisfactory decontamination efficiencies with low costs.

Chapter 23 - Integrated biorefinery concept for Indian paper and pulp industry, Megha Sailwal et al, Waste Biorefinery, Integrating Biorefineries for Waste Valorisation, 2020, pp.631-658. The paper and pulp industry generates different waste from the processing of raw material to paper production. The characteristics of the waste vary with the process and can be categorized as liquid discharge, solid and gaseous.

Among these the liquid discharge is the major concern as it possesses organic as well as toxic load. The existing treatment process doesn't focus on material recovery and hence the materials are lost with the waste stream. The integration of biochemical and thermochemical processes can aid in designing a paper and pulp waste biorefinery which will produce value-added chemicals, fuel, and energy. The concept of the biorefinery is based on the integration of the existing conversion processes to achieve material and energy recovery in the light of circular economy.

WOOD PANEL Mold and Larvae Resistance of Wood-Based Composites Incorporating Sodium Fluoride, Cihat Tascioglu et al, BioResources, Vol.15(1). The efficacy of particleboards manufactured with sodium fluoride against mold fungi and Hylotrupes bajulus (L.) larvae was tested. Laboratory-size particleboards were manufactured from untreated wood particles with inclusion of fine sodium fluoride (NaF) at the 1, 1.5, and 3% levels relative to total particle weight. Sodium fluoride was introduced as powder during the manufacturing process just before blending resin with wood particles. The laboratory mold test indicated that even the lowest level of retention of NaF with or without leaching significantly reduced mold growth on particleboard surfaces when compared to the untreated control specimens. The increased retention of NaF from 1% to 3% further suppressed mold growth towards lowest levels even on leached specimens. The laboratory Hylotrupes bajulus larvae tests revealed that the particleboard environment with or without NaF is not appropriate for larvacidial activity. While the tested biocide, NaF, tested positive against mold growth on particleboard surfaces, no effect was determined relative to larval deaths.

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Development of high-performance binderless fiberboards from wheat straw residue, Juan Domínguez-Robles et al, Construction and Building Materials, Vol.232. This study aims to develop fully bio-based lignocellulosic fiberboards from wheat straw fibers without any additional bonding agents. The wheat straw biomass was used to produce a semichemical pulp, which was treated by means of enzymatic refining, on the one hand, and mechanical refining, on the other. The morphological analysis for both refined fibers was assessed and compared to that of wheat straw semichemical fibers. The results revealed that length and width were decreased, whereas, fines in length were increased after the enzymatic treatment and mechanical refining. The fibers were used to produce high-density fiberboards by means of wet process. The physical and mechanical properties of the resulting binderless fiberboards from both refined fibers were characterized and compared to that of fiberboards from wheat straw semichemical pulp and the commercial ones. In both cases, it was found that the mechanical properties of the fiberboards were significantly higher than those commercial fiberboards, as well as the required by the standard regulations. These results lead not only to synthetic resin elimination, but also to the exploration of using agricultural waste in several sectors, as the panel-housing could be.

Use of basalt scrim to enhance mechanical properties of particleboards, Samuel Kramár et al, Construction and Building Materials, Vol.238. The particleboard (PB) industry faces a high demand for light, low-cost panels of specific mechanical properties.

This may be hard to fulfil because the density and strength of wood are linearly correlated.

Use of proper materials and composition, however, may result in panels of a high strengthto-weight-ratio. This allows saving raw wood and energy as the strengthened PB is useful for high-load-bearing application. A promising reinforcing material are basalt fibres. In this study, basalt fibres in the form of a scrim provided reinforcement inside the PB panel. The scrim used had an area weight of 360 g·m−2. Four compositions of 18 mm thick PBs and 640 kg·m−3 target density were produced using melamine-urea-formaldehyde (MUF) resin as the binder. Basalt scrims were positioned in the core, between the core and surface and in between both surface layers. The scrim used was either dry or additionally impregnated with MUF resin. The best variant proved to be the impregnated scrim placed in the middle of both surface layers. Its modulus of rupture (MOR) and modulus of elasticity (MOE) increased by 119 and 85% compared to the control panels, respectively.

The setup also improved internal bond strength, screw withdrawal resistance and thickness swelling. Thus, basalt scrims at the outer positions significantly enhance the strength-to-weight-ratio of PBs. Improving operation in an industrial MDF flash dryer through physics-based, Pedro Santos et al, Control Engineering Practice, Vol.94. Nonlinear model predictive control (NMPC) has increased popularity thanks to the availability of black-box models, systematically obtained from plant data via machine-learning procedures. Although this may be a good approach in the medium term, pure data-driven models quickly become outdated with changes in the process operation, so re-identification (training) routines are periodically required. Moreover, if the NMPC includes any economic objective to drive the process to a more efficient operation, these models often go beyond their validity range, which translates in a degraded control performance (high plant-model mismatch). In this work, the above issues are considered to model the drying section of an industrial medium density fibreboard (MDF) plant. The main contribution of this work is proposing a lumpedparameter grey-box model built upon first principles and completed with experimental equations, obtained from constrained regression with plant data. Upon this model, a moving-horizon estimator (MHE) is designed to estimate unmeasured inputs and states.

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Then, a mixed economic-tracking NMPC, which explicitly considers actuator-stiction compensation, is proposed to drive the dryer to the humidity setpoint by the most efficient path. Both optimisations are solved within the system sampling interval thanks to an efficient discretisation of the system dynamics by orthogonal collocation, and to the high computational performance achieved by modern software tools for numerical optimal control. The controller was firstly tested in simulation with a rigorous model of a generic MDF dryer, and it is currently implemented in the actual plant achieving significant performance improvements.

Natural Fibre Modification and Its Influence on Fibre-matrix Interfacial Properties in Biocomposite Materials, Stephen Amiandamhen et al, Fibers and Polymers (2020), online. Biocomposite materials manufactured from natural fibres and polymer matrix represent a group of engineered composite products with diverse applications. These materials continue to find increasing applications due to their design flexibility, superior properties and aesthetic appeal. The applicability of these biocomposites, however, depends on theinteraction in the fibre-matrix interface. This paper reviews the state of the art research in fibre-matrix interfacial interaction based on published literature. A brief background on biocomposite materials is presented. The focus of this review is the modification of natural fibres and its effect on fibre-matrix interfacial adhesion and properties. In addition, the effect of chemical treatment on fibre composition and fibrematrix interfacial bonding mechanism are discussed.

Greener adhesives based on UF/soy protein reinforced with montmorillonite clay for wood particleboard, Alejandro Bacigalupe et al, Journal of Applied Polymer Science (2020), online. There is a global concern about the types of adhesives used for the binding of wood particles, most of which include formaldehyde in their formulation. The aim of this work is to study the effect of raw montmorillonite (Mt) particles on blended urea formaldehyde (UF)/soy protein (SP) adhesives for the manufacture of wood particleboards to reduce the use of this carcinogenic component. Rheology showed that Mt does not alter the viscosity of adhesives at high shear rates, so they can be applied by spray.

Thermogravimetric analysis/derivative thermogravimetry (TGA/DTG) analysis revealed an enhancement of their thermal stability due to the presence of clay particles. Polymer–Mt interaction was studied by small amplitude XǦray scattering and scanning electron microscopy. According to these results, the exfoliated structure of the clay particles was achieved. Wood particleboards were manufactured with UF/SP/Mt adhesives in order to study their mechanical properties. The threeǦpoint bending test showed that Mt particles improved the modulus of both rupture and elasticity. UF/SP/Mt resins proved to be a prominent product for the development of environmentally friendlier particleboards with desirable mechanical properties.

Stiffness of Synclastic WoodǦBased Auxetic Sandwich Panels, Krzysztof Peliński et al, Physica Status Solidi (b) (2020), online. Auxeticity of materials improves several of their mechanical properties, especially shear, impact, and bending resistance. It also improves ability of materials to absorb impact energy as well as the overall stiffness of structures. In this research, authors examine synclastic panels made from novel woodǦ based composites. The aim is to determine the force–displacement characteristics during uniaxial compression and obtain the stiffness of the panels. These data allow one to predict the behavior of a panel during twoǦaxial bending with different support scenarios.

Finite element method (FEM) analysis is performed, with the use of model material, to determine the impact of varied facings thickness as well as different types of materials and core structures, on the stiffness of synclastic panels. It is demonstrated that proposed

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multilayer composites allow forming (technologically difficult) spherical shapes, without additional heat and pressure treatment. The type of an outer layer material strictly determines the usability and ease of twoÇŚaxial bending process. Presented composites are interesting materials, that can be adopted into the wood industry as a replacement for traditional materials, e.g., bent plywood.

Experimental Study on Combustion Properties and Thermo-Gravimetric Analyses of Oriented Strand Board (OSB), Fatih Yapici, Wood Industry / Drvna Industrija, Vol.71(1). This study investigates the effects of types of adhesives on the combustion properties of oriented strand board panels (OSB). Combustion test was performed according to ASTM E69 standard. Mass reduction, change of temperature and released gas (CO, NO, O2) were measured every 30 seconds during this test. Thermogravimetric analysis (TGA) of the OSBs was also carried out. While the highest temperature value of combustion was only obtained for the samples with phenol-formaldehyde at both outer and inner layer of test panels, the lowest temperature value was obtained for test samples with phenol-formaldehyde on the outer layer and isocyanate on the atinner layer. In the results of TGA, test mass reduction of OSBs was similar to each other, and most of the mass loss occurred at the temperatures between 200 and 400 °C. Evaluation of mechanical properties of OSB/3 after repetitive soaking and ovendrying cycles, Regino Kask et al, Wood Material Science & Engineering (2020), online. The objective of this study was to evaluate some mechanical properties of OSB/3 after one to ten cycles of soaking and oven/drying (accelerated aging). The modulus of rupture (MOR), modulus of elasticity (MOE), found by 3-point bending and screw withdrawal load (SWL), were determined in dry and wet conditions in the face and back surface, and in the cutting edge. The specimens were soaked for 24 hours and dried for 48 hours in a ventilated drying box. The MOR, MOE and SWL values dropped significantly after the first cycle, continued to decrease after three cycles and stabilized in the last cycles of soaking and drying. The surface and cross-sections of the samples were also studied using the X-ray technique. This analysis explained a significant decrease in the values of the studied properties after the first soaking cycle as a result of non-restored plastic deformation of the resin matrix. The low retention values of the studied properties could raise the durability issue of the investigated commercial OSB/3 boards as they should be moisture resistant according to EN 300:2006.

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Volume 6 Number 1, 2020

Forthcoming Events PITA Training Events

Page 1

Conferences & Exhibitions

Page 2

Webinars

Page 3

PITA TRAINING COURSES As might be expected, most physical face-to-face events have been cancelled for the foreseeable future. The situation with PITA training courses is similar to that for national or international conferences and exhibitions (next page). Nevertheless, at the time of writing PITA plans for some courses to take place later in 2020, as detailed below. (Up to date information can be found on The PITA Calendar.)

PITA ‘Bridging the Gap’ Course (Bury)

16th & 17th September 2020

PITA ‘Food Contact’ Course (Bury)

22nd September 2020

PITA ‘Energy Optimisation’ Course (Bury)

6th & 7th October 2020

PITA ‘Pump Efficiency’ Course (Bury)

13th October 2020

PITA ‘Introduction to Wet End Chemistry’ Course (Bury) 20th & 21st October 2020 PITA ‘Modern Papermaking’ Course (Bury) 3rd & 4th November 2020 PITA / PZG ‘Fundamentals of Papermaking’ (venue TBA) 24th to 26th November 2020

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CONFERENCES / EXHIBITIONS Many events planned for earlier this year were cancelled and have been re-scheduled for later this year, although this will require some semblance of ‘normality’ for them to take place, which at the moment is more an expression of hope than certainty. (Up to date information can be found on The PITA Calendar of World Events.)

Nevertheless, at the time of writing the main conference and exhibition events planned to take place in 2020 include: Paper One Show (Virtual Fair)

from 12 May (a clever way round the problem!)

CPA&G (Serbia)

17-18 June (note – very unlikely to occur!)

Tissue World (Bangkok)

9-11 Sept.

Tissue World (Istanbul)

15-17 Sept. (Tissue / Hygiene)

IMFA 2020 (Arizona)

24-26 Sept. (Moulded Pulp)

PRIMA 2020 (Rome)

28-29 Sept. (General)

PTS Biobased Solutions (Dresden)

6-7 Oct.

(Novel Chemistry)

MIAC 2020 (Lucca)

14-16 Oct.

(General / Tissue & Hygiene)

Paper & Biorefinery (Graz)

28-29 Oct.

General / Biotechnology)

Tissue World (Miami)

11-13 Nov.

(Tissue / Hygiene)

Technologiekring (Apeldoorn)

18-19 Nov.

(General)

(Tissue / Hygiene)

Going forward to 2021, these events are more likely take place: Tissue World Europe (Düsseldorf)

16-18 Mar.

(Tissue / Hygiene)

DRUPA (Düsseldorf)

20-30 Apr.

(Printing)

PulPaper (Helsinki)

27-29 Apr.

(General)

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WEBINARS One obvious change that has occurred over recent months with the COVID-19 pandemic is the rise in remote digital presentations. These are available on a very wide range of subject matter, as shown below. (In some cases registration is required.)

Health & Safety Subjects 3M EHS Fire Safety Matters series available Health & Safety Matters series available IOSH Occupational Health & Safety OHS Occupational Health & Safety SHP Safety & Health Practitioner Maintenance Subjects Pamarco Anilox Rolls (and some audio podcasts as well) Pilz (requires registration – webcode 150739) Plant Services and Maintenance Pumps & Systems UE Systems (ultrasound) Energy Matters GridBeyond Academy Environmental Matters FSLCI Life Cycle Analysis Textile Exchange (LCA of various textile materials) Water Matters International Water Association Nalco Veolia Water & Wastes Digest Welsh Water Tops Management & Leadership Centre for Creative Leadership Harvard Business Review Insignia Crisis Management Institute of Leadership & Management Paper Industry American Chemical Society recycling and the environment (single video) BioPRIA (Monash University, Australia – various subjects) RISI (global trends and summaries) TAPPI (technical subjects)

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Events