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Dirk Lechtenberg Dr. Hansjรถrg Diller

Alternative Fuels and Raw Materials Handbook for the Cement and Lime Industry volume 1


Dirk Lechtenberg, Dr. Hansjรถrg Diller

Alternative Fuels and Raw Materials Handbook for the Cement and Lime Industry

volume 1

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Dear Reader, Over the years, MVW Lechtenberg & Partner has been developing solutions for the processing of various types of wastes and biomass into alternative fuels. In these projects we have been designing suitable installations for processing, storage, dosing and feeding as well as evaluating environmentally relevant and process-specific influences and economics. These projects, in conjunction with long-term supervision of on-going production and quality-related parameters, have given us the benefit of first-hand experience. A few years ago we decided to summarise comprehensively the experience gained through our worldwide projects in written form, culminating in the AFR Handbook Volumes 1 and 2. We wish you much pleasure reading the wealth of experience collected and hope that this book assists you greatly in the execution of your projects. We will gladly place ourselves at your disposal should you have any suggestions or questions relating to the topics dealt with.

MVW Lechtenberg & Partner

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12-03-18 20:05


Dirk Lechtenberg Dr. Hansjรถrg Diller

Alternative Fuels and Raw Materials Handbook for the Cement and Lime Industry

volume 1


VLB-Meldung Lechtenberg, Dirk Diller, Dr. Hansjörg: Alternative Fuels and Raw Materials Handbook for the Cement and Lime Industry Publisher: MVW Lechtenberg Projektentwicklungs und Beteiligungsgesellschaft mbH, 2012 Düsseldorf: Verlag Bau+Technik GmbH ISBN: 978-3-7640-0550-4 by Verlag Bau+Technik GmbH Postfach 120110, 40601 Düsseldorf This work (including all elements thereof ) is protected by copyright. Any and all use or exploitation thereof beyond the strict limits of what is permitted under the German Copyright Act (Urheberrechtsgesetz) without the permission of the publisher (MVW Lechtenberg Projektentwicklungs -und Beteiligungsgesellschaft mbH) is prohibited and maybe be criminally prosecuted. The foregoing applies particularly to any and all duplication, translation, microfilming and storage and processing in IT systems. While the publisher has taken all reasonable care in the preparation of this book, the publisher makes no representation, express or implied, with regard to the accuracy of the information contained in this book and cannot accept any legal responsibility or liability for any errors or omissions from the book or the consequences thereof. The advice and strategies may not be suitable for your situation. You should consult with a professional where appropriate. Products and services that are referred to in this book may be either trademarks and/or registered trademarks of their respective owners. The publisher and authors make no claim to these trademarks. Print: B.o.s.s Druck und Medien GmbH, 47574 Goch Cover and text design: Krzysztof Spychal, Pre-Press Studio, www.spychal.pl Published and © by MVW Lechtenberg Projektentwicklungs -und Beteiligungsgesellschaft mbH, Solinger Strasse 19, 45481 Mülheim/Ruhr, Germany Project team: Dr. Hansjörg Diller, Anna Heiß, Joanna Korneluk-Bruns, Dirk Lechtenberg, Sarah-Christina Sureck info@lechtenberg-partner.de www.lechtenberg-partner.de

4


Preface

Preface To make it quite clear from the start: The use of “alternative fuels” in the cement and lime industry is not waste incineration “in disguise“. Alternative fuels, consisting of biomass or “refuse-derived fuels“ (RDF) have been used as a substitute for fossil fuels for around 30 years, especially in the cement industry and also to a small extent in the lime industry. As strict quality standards are set for cement clinker and lime products, the raw materials and fuels which are fed into the burning process need to be most precisely specified and be subject to constant monitoring. Rotary kilns in particular offer the ideal preconditions for recycling alternative fuels at extremely high temperatures with long residence times and in an environmentally friendly fashion. One of the indispensable prerequisites for this is securing the composition of the alternative fuels in compliance with the prescribed specifications, thereby minimising any possible negative effects on both emissions and end products. Some environmental associations impose strict measures for avoidance of all kinds of detrimental environmental effects resulting from employment of alternative fuels. As is widely known, detrimental environmental effects cannot be avoided in any combustion process. In order to minimise this effect, the cement and lime industry has been working for many years on emissionreducing measures. This handbook serves this purpose: Reduction of detrimental environmental effects supported by the drawing up of targeted information on utilisation of alternative fuels. In addition, it offers experience from many projects which has been compiled over the years. This is rounded off by practical advice as support and information for the cement and lime industry and for circles where this theme is addressed. The topic of alternative fuels in the cement and lime industry has gained considerable dynamism over the past few years. Rising fossil fuel costs and greater demands on climate-friendly production by using carbon neutral fuels – while achieving an unchanged product quality level – are the challenges which are linked to the employment of alternative fuels in modern cement and lime production. The field is naturally subject to constant development so this handbook can only give a current snapshot of the available technologies and experience. Owing to the wealth of information this handbook is divided into two parts. The first part describes alternative fuels in general, their production and utilisation. Furthermore, the specific machinery sections for alternative fuel production are discussed as well as quality management and effects on emissions and end products among alternative fuel users. The suitability of alternative fuels must generally be evaluated case by case based on chemical and physical properties as well as on production-specific and legally approved guidelines. The basic prerequisites and general guidelines for performing such suitability tests are also described. The second part of this handbook consists of a comprehensive list of Fact Sheets covering the most varied waste types and types of alternative fuels which currently have applications in the lime industry and moreover in the cement industry. A few Fact Sheets have been included in the volume at hand, but for lack of space the majority is compiled in Volume 2 of the AFR Handbook. The aim of these Fact Sheets is to advise as comprehensively as possible on availability, processing and influence of these materials on the production process as well as on the environment. This does not represent a general “free pass“ for the utilisation of the described materials as alternative fuels: Each waste type, each type of alternative fuel must be subjected to a detailed analysis and test for suitability.

5


Preface The authors’ 20-year experience in the spheres of production and utilisation of alternative fuels as well as of many completed projects worldwide have been incorporated into this handbook. This information mass is corroborated by numerous references to specific citations. In the domain of alternative fuels there is indeed a wealth of publications but they only deal with special, partial aspects of the topic. A summary description covering the entire range of aspects has been missing until now. This hole should be filled with the compendium at hand. Mßlheim an der Ruhr, Germany, February 2012

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Content

Content Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 List of Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 List of Chemical Formulae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

PART I Chapter: 1 History and overview of alternative raw materials and fuels . . . . . . . . . . . . 27 1.1 Alternative raw materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 1.1.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1.2 History and utilisation of alternative raw materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1.3 Types of alternative raw materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1.4 Characteristics of alternative raw materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1.5 Principles when using alternative raw materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1.6 Utilisation of alternative raw materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1.7 Transport and storage of alternative raw materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1.8 Conditioning and dosing of alternative raw materials . . . . . . . . . . . . . . . . . . . . . . . . . 1.1.9 Quality assurance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1.10 Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

27 28 28 30 33 34 39 39 41 44

1.2 Alternative fuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 1.2.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2.2 History of alternative fuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2.3 Types of alternative fuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2.4 Waste as raw material for alternative fuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2.5 Identification of wastes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

45 46 50 52 53

Chapter: 2 Waste evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 2.1 Defining waste generating sectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 2.2 Collecting the required information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 2.3 Quantification and characterisation of the mixed waste . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

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Content 2.4 Quantification of waste from generators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 2.5 Fuel-technical properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 2.6 Basic principles for the use of alternative fuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

Chapter: 3 Key issues for investments in RDF production technologies and alternative fuel usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 3.1 Basic economic considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 3.2 Criteria influencing the production of waste-derived fuels . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Chapter: 4 Production of RDF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 4.1 Separation technologies – impurities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 4.2 Screening technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 4.2.1 4.2.2 4.2.3

4.3 4.4 4.5 4.6 4.7

Drum screens/trommel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 Ballistic separation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 Oscillating or vibrating screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Air classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 Hard/rigid material classifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 Manual separation/hand picking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 Optical sorting systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 Metal separation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 4.7.1 4.7.2

Separation of ferrous materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 Non-ferrous separation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

4.8 Shredding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 4.8.1 Pre–shredding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 4.8.2 Final shredding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

4.9 Pelletising . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 4.10 Drying technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 4.10.1 4.10.2 4.10.3 4.10.4

Solar drying . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 Belt dryers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120 Drum dryers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122 Notes on dryer systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

4.11 Examples of RDF production plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 4.12 Economic evaluation of RDF production plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

Chapter: 5 Quality management for alternative fuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 5.1 Environmentally relevant elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 5.2 Contaminant sources in alternative fuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134 5.3 Investigation of alternative fuels – declaration analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138

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Content 5.4 5.5 5.6 5.7

Evaluation of waste and alternative fuels in an RDF production plant . . . . . . . . . . . . . . 143 Evaluation of AF in the cement/lime plant – sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147 Sample preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149 Analysis of alternative fuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 5.7.1 Preliminary notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 5.7.2 Moisture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154 5.7.3 Volatiles and ash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156 5.7.4 Calorific value . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156 5.7.5 Chlorine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159 5.7.6 Sulphur . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160 5.7.7 Trace elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

5.8 Monitoring and reporting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

Chapter: 6 Logistics and storage of RDF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165 6.1 6.2 6.3 6.4 6.5

Basic principles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165 Transport, loading of alternative fuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165 Truck reception . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169 Reception systems for bulk solid materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175 Storage of alternative fuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176 6.5.1 Basic requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176 6.5.2 Homogenisation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177 6.5.3 Special section: Fire protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178 6.5.4 Fire protection evaluation using the example of a storage facility . . . . . . . . . . . . . 182 6.5.5 Verification of infrastructural fire protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191 6.5.6 Explosion protection in secondary fuel storage facilities . . . . . . . . . . . . . . . . . . . . . 194

6.6 Types of storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195 6.6.1 6.6.2 6.6.3 6.6.4 6.6.5 6.6.6

Storage as bulk material in an enclosed facility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196 Storage in one or several silos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197 Moving floor storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198 Storage in a deep bunker with discharge systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200 Storage in a bunker with crane unloading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201 Storage in special storage boxes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203

Chapter: 7 Dosing and feeding of alternative fuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207 7.1 Screening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207 7.2 Separation of impurities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212 7.3 Conveying technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212 7.3.1 7.3.2

Pneumatic conveying . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212 Mechanical conveying . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217

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Content 7.3.3

Pipe conveyors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220

7.4 Weighing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221 7.4.1 Fundamentals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221 7.4.2 Weigh feeders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222 7.4.3 Differential weigh feeders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222 7.4.4 Rotor weigh feeder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223 7.4.5 Screw weigh feeder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224

7.5 Feeding points for alternative fuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225 7.5.1 7.5.2 7.5.3 7.5.4

Basic considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225 Main burner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227 Kiln inlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236 Dosing of alternative fuels in the calciner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237

Chapter: 8 Influences on clinker and lime production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239 8.1 Ash composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239 8.2 Sulphur, chlorine, alkalis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244 8.3 Influence on lime production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250 8.4 Refractories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251 8.5 Grain size of fuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254 8.6 Environmentally relevant trace elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256 8.6.1 Influence of trace elements on cement properties – strength and setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260 8.6.2 Leaching of trace elements in fresh cement paste and hardened concrete . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261

8.7 Impact on fan capacities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263 8.7.1 8.7.2

Calculation basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263 Example of a substitution scenario . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265

8.8 Specific energy consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266 8.9 Remarks on quality control of the cement production process when using alternative fuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267 8.10 Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269 8.11 CO2 reduction with alternative fuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273 8.11.1 Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273 8.11.2 Biomass content and emission factors of alternative fuels . . . . . . . . . . . . . . . . . . . . 274 8.11.3 Determination of biogenic content – mass balance . . . . . . . . . . . . . . . . . . . . . . . . . . . 275 8.11.4 Determination of biogenic content – manual sorting, selective dissolution, 14 C method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276 8.11.5 Fossil CO2 savings in the cement and lime industry . . . . . . . . . . . . . . . . . . . . . . . . . . . 277

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Content

Chapter: 9 Contracting alternative fuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287 9.1 9.2 9.3 9.4

Structure for waste sourcing and AFR units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287 Price evaluation and contracting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289 Contract structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291 Bonus/malus regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291

Chapter: 10 Emission limits and permitting issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293 10.1 10.2 10.3 10.4 10.5 10.6

Monitoring of emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295 Monitoring of safe combustion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296 Permitting issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298 Applying for a permit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298 Trial permit – organisation of trials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302 Public discussions – stakeholders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305

Chapter: 11 Current developments of the use of alternative fuels . . . . . . . . . . . . . . . . . . . . 309 11.1 11.2 11.3 11.4

Oxy-fuel technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 309 Ultra fine milling of alternative fuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312 Thermal technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314 Pyrolysis of high-calorific residues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318 11.4.1 Fundamentals of pyrolysis technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318 11.4.2 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319 11.4.3 Hydrothermal carbonisation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 321

Annex I Questionnaire for data collection landfill site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323 1. General information on landfill site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323 2. General information on the current situation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324 3. Waste input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 326

Annex II Quality management – Examples of excerpts of process instructions for the processing plant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 327 Annex II a Process instructions for the processing plant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 328 Annex II b Work instructions for sampling waste input and RDF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338

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Content Annex II c Operational procedures for maintenance and repairs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 343 Annex II d Specification for the acceptance of municipal mixed wastes (MMW) . . . . . . . . . . . . . . . . . . . . 346 Annex II e Company Safety Instructions RDF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349

PART II Fact Sheet: Alternative fuel and raw material (AFR) review “Olive residues” . . . . . . . 353 1

Classification according to EWC European Waste Catalogue . . . . . . . . . . . . . . . . . . . . . . . 353 1.1 1.2

2

AFR description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353 AFR pictures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 354

AFR source and composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 354 2.1 Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 354 2.2 Quantity and availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 356 2.3 Flow chart of AFR production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 358 2.4 AFR composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 358 2.5 AFR analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 359 2.6 AFR ash composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360

3 4

Harmful substances and hazardous characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 361 Collection, recycling and disposal of the AFR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 361 4.1 4.2 4.3

Collection and transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 361 Recycling, current use and disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 361 Use as alternative fuel in a cement or lime plant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362 4.3.1 Economic value of the waste in a cement or lime plant . . . . . . . . . . . . . . . . 362 4.3.2 AFR pre-processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363 4.3.3 Storage at the plant site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364 4.3.4 Dosing and feeding systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364 4.3.5 Quality influence on clinker and lime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 365

5 Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 367 6 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 367

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Content

Fact Sheet: Alternative fuel and raw material (AFR) review “Poultry litter” . . . . . . . . 369 1

Classification according to European Waste Catalogue EWC . . . . . . . . . . . . . . . . . . . . . . . 369 1.1 1.2

AFR description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369 AFR pictures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 370

2

AFR source and composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 371 2.1 Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 371 2.2 Quantity and availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 371 2.3 Flow chart of AFR production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 373 2.4 AFR composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374 2.5 AFR analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374 2.6 AFR ash composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 375

3 4

Harmful substances and hazardous characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 375 Collection, recycling and disposal of the AFR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 376 4.1 4.2 4.3

Collection and transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 376 Recycling, current use and disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377 Use as alternative fuels in a cement plant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377 4.3.1 Economic value of the waste in a cement plant . . . . . . . . . . . . . . . . . . . . . . . 377 4.3.2 AFR pre-processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378 4.3.3 Storage in the plant site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378 4.3.4 Dosing and feeding systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378 4.3.5 Quality influence on clinker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379

5 Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379 6 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379

Fact Sheet: Alternative fuel and raw material (AFR) review “Scrap tyres” . . . . . . . . . . . 381 1

Classification according to European Waste Catalogue EWC . . . . . . . . . . . . . . . . . . . . . . . 381 1.1 1.2

2

AFR description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 381 AFR pictures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 382

AFR source and composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 383 2.1 Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 383 2.2 Quantity and availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 383 2.3 Flow chart of AFR production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 385 2.4 AFR composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 386 2.5 AFR analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 387 2.6 Thermal properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 389

3 4

Harmful substances and hazardous characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 389 Collection, recycling and disposal of the AFR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 390 4.1

Collection and transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 390

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Content 4.2 4.3

Recycling, current use and disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 390 Use as alternative fuels in a cement plant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 391 4.3.1 Economic value of the AFR in a cement plant . . . . . . . . . . . . . . . . . . . . . . . . . 391 4.3.2 AFR pre-processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392 4.3.3 Storage at the plant site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392 4.3.4 Dosing and feeding systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 393 4.3.5 Quality influence on clinker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395

5 Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395 6 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 396

Fact Sheet: Alternative fuel and raw material (AFR) review ”Sewage sludge” . . . . . 399 1

Classification according to European Waste catalogue EWC . . . . . . . . . . . . . . . . . . . . . . . 399 1.1 1.2

AFR description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 399 AFR picture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400

2

AFR source and composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400 2.1 Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400 2.2 Quantity and availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 402 2.3 Flow chart of AFR production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 403 2.4 AFR composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 404 2.5 AFR analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 405 2.6 AFR ash composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 406

3 4

Harmful substances and hazardous characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 407 Collection, recycling and disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 408 4.1 4.2 4.3

Collection and transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 408 Recycling, current use and disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 409 Use as alternative fuel in a cement plant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 410 4.3.1 Economic value of the AFR in a cement plant . . . . . . . . . . . . . . . . . . . . . . . . . 411 4.3.2 AFR pre-processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 412 4.3.3 Storage at the plant site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 415 4.3.4 Dosing and feeding systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 416 4.3.5 Quality influence on clinker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417

5 Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 418 6 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 418

14


Content

Fact Sheet: Alternative fuel and raw material (AFR) review “Straw” . . . . . . . . . . . . . . . . . . 423 1

Classification according to European waste Catalogue EWC . . . . . . . . . . . . . . . . . . . . . . . 423 1.1 1.2

AFR description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 423 AFR pictures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 424

2

AFR source and composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 424 2.1 Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 424 2.2 Quantity and availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 425 2.3 Flow chart of AFR production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 425 2.4 AFR composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 426 2.5 AFR analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 427 2.6 AFR ash composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 428

3 4

Harmful substances and hazardous characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 428 Collection, recycling and disposal of the AFR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 429 4.1 4.2 4.3

Collection and transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 429 Recycling, current use and disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 430 Use as alternative fuels in a cement plant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 431 4.3.1 Economic value of the waste in a cement plant . . . . . . . . . . . . . . . . . . . . . . . 431 4.3.2 AFR pre-processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 432 4.3.3 Storage at the plant site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 432 4.3.4 Dosing and feeding systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 433 4.3.5 Quality influence on clinker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 433

5 Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 435 6 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 436

Fact Sheet: Alternative fuel and raw material (AFR) review “Used oils” . . . . . . . . . . . . . 439 1

Classification according to European Waste Catalogue EWC . . . . . . . . . . . . . . . . . . . . . . . 439 1.1 1.2

2

AFR description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 440 AFR pictures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 440

AFR source and composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 441 2.1 Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 441 2.2 Quantity and availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 442 2.3 Flow chart of AFR production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 444 2.4 AFR composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 445 2.5 AFR analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 445 2.6 AFR ash composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 447

3 4

Harmful substances and hazardous characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 447 Collection, recycling and disposal of the AFR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 448 4.1

Collection and transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 448

15


Content 4.2 4.3

Recycling, current use and disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 449 Use as alternative fuels in cement or lime plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 450 4.3.1 Economic value of the AFR in cement or lime plants . . . . . . . . . . . . . . . . . . . 451 4.3.2 AFR pre-processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 452 4.3.3 Storage at the plant site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 453 4.3.4 Dosing and feeding systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 453 4.3.5 Quality influence on products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 453

5 Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 454 6 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 455

Clinker Formulae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 457 Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 459 Table of Figures

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 475

Table of Pictures

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 479

Table of Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 485 Advertisement Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 489 Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 495

16


PART I


History and overview of alternative raw materials and fuels

Chapter: 1

History and overview of alternative raw materials and fuels

1.1

Alternative raw materials

1.1.1

Definition

What are alternative raw materials? The World Business Council for Sustainable Development [W-5] provides the following definition: “Selected waste and by-products containing useful minerals such as calcium, silica, alumina, and iron can be used as raw materials in the kiln, replacing raw materials such as clay, shale, and limestone.” [W-5] “Alternative raw materials” are often also known as “secondary raw materials”.

Alternative or secondary raw [W-5] further explains that some materials have both useful mineral content and recov- materials

erable calorific value. Therefore, the distinction between alternative fuels and raw materials is not clear in every case. For example, sewage sludge has a low but significant calorific value, and burns to give ash containing minerals useful in the clinker matrix. While the aforementioned definition focuses on clinker production, alternative raw materials are also applied for the cement grinding process. They can be used to control the setting time of the cement (synthetic gypsum), they may have cementitious properties (granulated blast furnace slag), or they may be completely inert.

The term “alternative raw materials”, in keeping with the above definition [W-5] is closely linked to the term “waste”. The latter is in many regards linked to negative conceptions which can lead to unobjective discussions about where alternative raw materials end up and about their effects. The EU Commission [E-22] describes that the evolving jurisprudence and relative absence of legal clarity has in some cases made the application of the definition of waste on this issue difficult for the competent authorities and economic operators alike. This might lead to differing case by case solutions based on similar facts by competent authorities in different Member States of the European Union. As a result, inequalities in the treatment of economic operators and obstacles in the internal market appear. An excessively wide interpretation of the definition of waste imposes unnecessary costs on the businesses concerned and can reduce the attractiveness of alternative raw materials that would otherwise be returned into the economy.

Controversial opinions about classification to waste or product

27


Chapter 1 A good example of a change in classification as waste or by-product is slag. In 2007 the EU Commission defined [E-22]: Example: Blast “Blast furnace slag is produced in parallel with hot iron in a blast furnace. The production furnace slag process of the iron is adapted to ensure that the slag has the requisite technical qualities.

A technical choice is made at the start of the production process that determines the type of slag that is produced. Moreover, use of the slag is certain in a number of clearly defined end uses, and demand is high. Blast furnace slag can be used directly at the end of the production process, without further processing that is not an integral part of this production process (such as crushing to obtain the appropriate particle size). This material can therefore be considered to fall outside of the definition of waste.”

Preconditions So that a material can be classified not as a waste but as a by-product, the following prefor classification conditions must be met [E-22]: as by-product

1. The material is certain to be used. 2. No further processing is required prior to use. 3. The material is used as an integral part of the continuous production process.

Furthermore, [E-22] points out that additional factors should be considered in deciding whether a material should be classified as a by-product. These factors include the environmental impact of using the material, and whether any special precautions are needed for its use.

1.1.2

History and utilisation of alternative raw materials

There were very early attempts in the cement industry to capture raw materials which

First example for do not occur naturally. So one recognised ecological and economic value of blast-furan alternative nace lump slag, a waste product from steel production. Blast furnace slag possesses conraw material siderable lime, silicon and aluminium content. Also this material has no ignition loss so

that when using it as a clay substitute considerable amounts of fuel are saved. For when being substituted by blast furnace slag less CO2 is emitted from the raw meal than if the entire lime content came from the limestone. In 1883 the “Portland-Cement-Fabrik First cement plant Narjes & Bender” in Essen-Kupferdreh (Germany) was the first to start production accordwhich used blast ing to this process. Later on, simultaneous use of blast furnace lump slag as clinker raw furnace slag material and granulated blast furnace slag as cement constituent was typical for the cement plants which were operated by the steel industry for Portland slag cement and blast furnace slag cement production [E-21]. Subsequently the range of alternative raw materials for the cement production process became ever more widespread which can bring an economic advantage for cement plants and be understood as environmentally friendly. Nowadays a wide range of alternative raw materials is used which are presented in the following.

1.1.3

Lime plants need limestone of high purity Cement plants use a variety of materials

28

Types of alternative raw materials

As is well known, cement and lime plants use huge amounts of raw materials. This explains the selection of plant locations by the presence of the required natural raw material sources in order to minimise transport distances for raw materials. While lime plants cope with a single raw material type – limestone – which must generally be very pure, cement plants usually need several raw materials to be able to set up the required clinker chemistry based on key figures like lime saturation factor, silicate and aluminium modules. The element calcium is supplied in the form of limestone, chalk or marl. Clay, slate, sand and iron ores contribute the other elements required – silicon, aluminium


History and overview of alternative raw materials and fuels and iron. For cement grinding natural materials – gypsum, anhydrite, limestone, pozzolan – are utilised. It is taken for granted that not all necessary raw materials are available on site at a cement plant. Certain raw material content has to be purchased and transported over longer distances. Against the background of a generally increased environmental awareness, recovery of mineral residues is a socio-political task which makes a massive contribution to conserving natural resources. In this context the use of such alternative raw materials, particularly in the cement industry, brings a multitude of advantages, such as: ƒƒ Conservation of natural resources ƒƒ Reduction of landfill space which would otherwise be necessary for these materials ƒƒ Reintroduction of waste materials into the value creation chain (recycling)

Recovery of waste comes with environmental and social responsibility

Chemical characterisation takes place based on a  ternary diagram, in which the clinker production related components CaO, SiO2 as well as Al2O3 + Fe2O3 are taken into account. The following Rankin diagram shows the typical constituents of the most important alternative raw materials. The assigned areas are not fixed as the compositions of the materials may vary depending on the origin of the raw materials. For comparison purposes the approximate clinker composition is also indicated.

J

H A B D

E C F G

I

A = Crushed brick; B = Coal ash; C = Lignite ash; D = Paper residues; E = Blast furnace slag; F = Clinker; G = Lime residues; H = Aerated concrete meal; I = Burnt pyrites, mill scale; J = Spent foundry sand

Figure 1: Rankin diagram with indications of the chemical compositions of different alternative raw materials according to [D-17]

Alternative raw materials can be subdivided according to their main constituents in Classification calcium, silicon, aluminium, iron, sulphur or fluorine bearing materials. As an example, according to main the next table shows a few alternative raw materials and their possible applications in constituents cement plants:

29


Chapter 1

Category

Material

Ca-bearing materials Lime sludge Carbide sludge Industrial lime sludge Lime grits Egg shells, mussel shells Si-bearing materials Spent foundry sand Aerated concrete meal Fe-bearing materials Burnt pyrites Mill scale

Al-bearing materials Si-, Al-, Ca-bearing materials

Table 1: Examples of alternative raw materials according to data from [D-17] and [S-13]

S-bearing materials F-bearing materials

1.1.4

Converter dust Red mud Synthetic haematite Waste from metal industry Blast furnace slag Crushed bricks Paper residues Residues from natural stone processing Ashes from power plants: Fly ash Coal ash Lignite ash FGD gypsum Chemical gypsum CaF2 filter cake

Relevant secondary constituents

Purpose Ca-correction

C, NH3

Cr Ca

Si-correction

Cr and other heavy metals Cr and other heavy metals

Fe-correction

Al-correction Ti, Na Na, K Ca, Na, Ti, Mg

Si-, Al-correction, for some ashes also Fe-correction

K, V Setting time P, citric acid Reduction of sintering temperature

Characteristics of alternative raw materials

In the following, alternative raw materials are briefly characterised:

Ca-bearing materials: Lime residues from Industrial lime residues occur inter alia in sugar manufacture. In sugar production lime sugar plants milk is employed for cleaning of sugar-cane juice. For this reason sugar factories fre-

quently operate lime kilns. The undersized particles of raw material limestone as well as low burnt qualities and grits represent high quality lime components for raw meal production [D-17].

30


History and overview of alternative raw materials and fuels With water decarbonisation, depending on the process involved, calcium carbonate occurs Lime residues from in the form of “pearls” or sludge [J-1] which is equally suitable as a limestone substitute. water treatment Carbide lime is a by-product from nitrogen fertiliser production. Carbide lime contains Lime residues from 90 – 95% calcium carbonate as well as up to 10% carbon and a small proportion of fertiliser production ammonium compounds. The latter makes itself known through a strong ammonia odour in its fresh state and is most intensive during material unloading. Egg shells occur in foodstuff production and represent rather exotic raw materials. Egg Egg shells shells contain protein residues whose decomposition involves development of an intensive odour. The egg white residues stick to the egg shells which hampers handling. Handling can however be improved by blending with other raw material components [D-17]. What also needs to be taken into account is the organic matter of the egg content of the egg shells and possible TOC emissions when being employed as raw meal components.

Si-bearing materials: Spent foundry sand comes from foundries, where natural sand with high quartz content Spent foundry sand is used for the moulds. After use the spent foundry sand is suitable as silicon-bearing material for setting up the silicate module in the raw meal. It must be noted that prior to use in the raw mill the spent foundry sand must be relieved of contaminants (metallic casting residues of aluminium and iron) [D-17]. Moreover, the spent sand can contain residues of organic binders which can lead to possible TOC emissions. Residues from aerated concrete production (e.g. cut-offs from aerated concrete blocks) Aerated concrete contain calcium silicate. The material is soft, mainly flour-like. It can be added most advantageously to the raw meal or even to the kiln meal. Aerated concrete meal contains little CO2 [D-17].

Fe-bearing materials: For the setting up of iron content in the raw meal a range of industrial by-products is suitable: Mill scale occurs on rolling mills in steel plants. Apart from oxide and metallic iron mill Mill scale scale also contains oily constituents. TOC emissions from raw mill grinding as well as possible adverse effects in separation performance in electrostatic precipitators as a result of vaporous oil need to be taken into account [D-17]. In pyrite calcination (FeS2) for sulphuric acid production, pyrite cinders, mainly iron Pyrite cinders oxide, occur. In the case of all iron-bearing materials a possible increased penetration of minor components (e.g. chrome) needs to be taken into account.

Si-, Al-, Ca-bearing materials: Crushed brick originates from building rubble processing or from inferior qualities in Crushed bricks brick production. From a chemical point of view crushed brick corresponds to the ignition-loss free brick raw material, clay. As such, crushed brick can be effectively employed for the setting up of the silicate and alumina module. The minor components, alkalis, need to be noted which on average amount to approximately 1.6% Na2O equivalent [D-17]. From a chemical point of view ashes from coal-fired power stations cover a wide field. Power plant ashes Depending on coal varieties ash from coal-fired power stations can be rich in calcium (e.g. lignite ashes) or rich in silicates (e.g. hard coal ashes). Boiler ash as well as fly ash

31


Chapter 1 can be used as raw meal components. Carbon residue content from incomplete combustion, among others, is relevant as a minor component as well as – depending on coal origin – trace elements and increased sulphur content [D-17]. If waste material, such as sewage sludge is co-incinerated in a power station, higher phosphorus content in the power station ash should be anticipated. Blast furnace slag Blast furnace slag is generated from the smelting of ores. The lime binds the minor com-

ponents – silicates and aluminates – contained in the ores. Slowly cooled blast furnace slag is predominantly crystalline and is known as lump slag. Lump slag has no hydraulic reactivity. If blast furnace slag is cooled rapidly in granulators by means of water a glass-like material is usually created which is known as granulated blast furnace slag. This material is latently hydraulic. Lump slag as well as granulated blast furnace slag can be used for raw meal production. Both materials have the advantage that they show no ignition loss and as such make a valuable contribution to the reduction of CO2 emissions in a cement plant [D-17]. Increased wear in the roller mill should be anticipated especially when using granulated blast furnace slag for raw meal grinding. Owing to its latent hydraulic properties granulated blast furnace slag has been successfully used for decades as a clinker substitute in Portland slag cements (CEM II) and blast furnace slag cements (CEM III), thereby assisting cement plants once again in the reduction of CO2 emissions.

S-bearing materials: These materials are used as alternative raw materials for cement grinding as a regulator

Gypsum of setting times. Here mainly FGD gypsum as well as synthetic gypsums should be menfrom flue-gas tioned which occur in various chemical processes. FGD gypsum originates from flue-gas desulphurisation desulphurisation plants in power stations and is a fine-particle material. It can happen

that unburned coal residues remain in the gypsum which float in the cement paste and leave behind black streaks on the concrete surface, giving rise to complaints. Synthetic gypsums occur as a waste product in fertiliser and phosphoric acid produc-

“Phosphorgypsum” tion. This “phosphorgypsum” contains phosphates which can extend cement setting

times more than anticipated.

Apart from use as a setting regulator in cement grinding, synthetic gypsums are also used in raw meal grinding. The degree of sulphidisation of the alkalis in the clinker is controlled in this way.

F-bearing materials: Mineraliser Calcium fluoride is used in some cement plants as a mineraliser to reduce the sinter tem-

perature. As is well known fluoride promotes formation of C3S and decreases the lower temperature limit of the C3S stability range from 1,250°C to values below 1,200°C [L-2]. Natural fluorspar can be substituted by industrial CaF2 bearing waste materials. CaF2

Calcium fluoride occurs in waste incineration plants, in which fluorine bearing organic compounds are from incineration burned. Here fluorine is removed from the waste gas with lime hydrate whereby CaF2 plants forms which is available in the form of a filter cake. Calcium fluoride CaF2 occurs in glass processing during pickling of glass with hydrofluoric acid. The excess from glass hydrofluoric acid is neutralised with lime and the precipitated CaF2 is separated in the processing form of a filter cake.

32


Production of RDF

Chapter: 4

Production of RDF

The technical preparation expenditure depends in each case on the later or final utilisation of the alternative fuels and of the assigned wastes. With relatively homogeneous waste or residues such as commercial or industrial wastes, the preparation process mainly consists of a varying number of cutting or shredding steps. The basic principle is chemical suitability and burning ability for a co-incineration or mono incineration process. The aim is to produce an optimum homogeneous product for incineration. The more heterogeneous the wastes or residue streams are, the more ambitious the requirements are for the technology of processing them into alternative fuels. Apart from multi-level shredding, a various array of classifying processes is necessary for the production of a high-quality alternative fuel. Typical processing steps in RDF preparation plants are: Technical device

Working principle

Pre-separation of bulky material or impurities before feeding by excavator

Sorting

Screening by drum screen

Size classification

Screening by vibrating screen

Size classification

Screening by disc screen

Size classification

Ballistic separation

Round or plain part classification

Air classifying

Classification according to surface/weight relation

Ferrous and non-ferrous separation

Magnetism, eddy current

NIR separation (near infrared) or optical sorting

Classification according to material (negative or positive selection)

Pre-shredding and final shredding

Size reduction

Table 17: Typical technical devices and working principles in an RDF processing plant (Source: MVW)

In processing plants the waste or residues will be pre-sorted in a first step to separate larger Pre-sorting as impurities and foreign particles prior to pre-shredding. This can be done easily by using an initial waste excavator. Usually after the pre-shredding step a first screening step takes place. The mesh treatment size of this screen is between 15 and 50mm depending on the input material. The material will be screened into different grain sizes. This step depends mainly on the input waste. For instance, when processing municipal solid waste in developing countries, a first screening step is strictly recommended to separate fines, such as stones and minerals and to prevent the downstream technical devices from damage. In developing

83


Chapter 4 countries the amount of organics and minerals in mixed municipal solid wastes is much higher than in developed countries which can be traced back to a high content of street sweepings and collection at roadsides. This difference depends on the present, separate collection and/or transfer station systems for waste. The separation at the point of origin for waste is common practice in developed countries, whereas no such separate, but mixed waste collection is current practice in developing countries. Extraction of fines improves RDF quality and equipment lifetime

The separation of fines, consisting mainly of organics and inert materials, reduces wear impact on the processing equipment and increases the product quality. The separation and rejection of fine materials also increase the calorific value of the remaining, larger sized fractions. Besides air separation, ballistic separators are used.

Extraction of The depletion of chlorine materials is made by NIR (near infrared) technology. In this chlorine-bearing processing step, either materials which are suitable for alternative fuels or for example materials chlorine-bearing material will be separated from the material flow (separation in terms

of a positive or negative sorting).

Extraction Ferrous and non-ferrous metals are separated by overbelt magnet and eddy current of metals separators respectively. After the sorting process – screening or pre-separation – the

alternative fuels will be shredded into their final grain size (approximately 15 to 40mm). As described above, the alternative fuel processing plant consists of different processing steps, depending on the composition of the input material (commercial waste, industrial waste or mixed household waste) as well as on the products to be made. Splitting of the material stream into different fractions, each with their own attributes such as grain size, flatness or two-dimensionality, surface/weight relation, specific chemical and/or physical parameters such as density and splitting of the mass flow are some of the key factors to process alternative fuels from mixed input waste.

Basic Equipment Input

Figure 12: Schematic presentation for the basic equipment for an RDF production plant (Source: MVW)

Screening/ pre-sorting

Primary shredding

Ferrous and non-ferrous separation: Overbelt magnet and non-ferrous separator

Heavy fraction separation

Secondary shredding/ granulation

Output Ferrous and non-ferrous metals

Heavy parts

granulate (flakes)

(size app. 15 – 40mm)

In the following relevant technologies for the production of waste-derived fuels are described.

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Production of RDF

4.1

Separation technologies – impurities

Separating out the suitable waste fractions from a waste mixture such as household waste has a decisive influence on the alternative fuel being produced. It is critical to remove all foreign matter which could add a negative characteristic to the fuel being produced and subsequently to the clinker/lime as well as to emissions. Among this foreign matter are for example special wastes (batteries, coin cells, fluorescent lamp parts, Removal of energy-saving lamps, electronic scrap), chlorine-bearing wastes (PVC-bearing plastics, contaminants rubber) and chrome-bearing wastes (leather). A too high inert proportion in the alter- is essential native fuel leads to a higher contamination with trace elements which must be avoided. Examinations have shown that the inert portion of wastes is frequently highly contaminated with trace elements. Also the moisture content in the fine fraction is frequently considerably higher than in screened, coarser material fractions. An example of an examination is shown in the next table: Sample  

Fraction size  

Moisture

Ash

[%]

[%]

Net calorific value [MJ/kg]

Chlorine [%]

RDF (pure plastics)

>32mm

3.9

2.2

36.99

1.10

RDF (pure plastics)

5 – 32mm

10.0

3.8

34.10

1.15

RDF (pure plastics)

<5mm

17.2

13.0

32.70

0.91

RDF (mixed plastics, paper…)

>32mm

11.2

13.1

26.63

1.22

RDF (mixed plastics, paper…) 5 – 32mm

21.0

5.5

23.73

2.79

RDF (mixed plastics, paper…)

30.1

11.2

17.09

0.88

<5mm

Table 18: Relationship of fuel parameters on grain sizes (Source: MVW)

85


Chapter 4 Furthermore, any foreign matter or contaminants which negatively influence the prep-

Impact on aration process need to be separated out. These are for example iron, non-ferrous metwear: Metals, als or larger stones but also inert materials (e.g. sand) which lead to higher wear in the stones, sand shredding equipment.

Basically the rule applies that recyclable fractions which can be recycled for their raw materials or basic materials should be fed to such a  recycling process. Only waste materials which can not be reprocessed or recycled for environmental economic reasons can be processed into alternative fuels.

Picture 12: Pre-separation of disruptive materials by wheeled loader with grip (Source: MVW)

Separation of Organic waste fractions such as kitchen waste, food or garden waste should also be organic fractions separated in order to increase the product characteristics of the desired alternative fuel. indispensable Such wastes are frequently very moist, with water contents of up to 80%. Drying (see

chapter 4.10) might be an option, but it is highly investment and energy intensive. Furthermore, salts (table salts, NaCl) in food remains stand at around 0.3%. Hence, kitchen waste should not be employed as fuel. Basically, separate capture of organic wastes in households and the subsequent environmentally sound material recycling (composting, aerobic or anaerobic fermentation) and usage as fertiliser is preferred. Focused quality management with continuous analysis of the materials to be processed is the basic precondition of successful processing of wastes into alternative fuels. More detailed information on this subject can be found in chapter 5.

4.2

Screening technology

4.2.1

Drum screens/trommel

A drum screen or trommel is a screened cylinder which is used to separate materials by size – for example, separating the biodegradable fraction of mixed municipal waste or separating different sizes of crushed stone. The main task of the screen is to segregate A variety of mesh an input fraction into two or three different output fractions. The mesh size of a drum sizes applicable screen is variable, for each possible fraction an example is given: medium size material (>30mm to <250mm), overflow material (>250mm) and fines (<30mm).

86


Production of RDF Before feeding the material into the pre-shredder the drum screen separates the fines (e.g. <30mm, e.g. stones, sand, soil). This fraction is conveyed to a container positioned below the drum screen which has to be replaced from time to time. This material is qualified for further processing either outside of the alternative fuels processing plant or for landfill.

Picture 13: Example of a drum screen unit (left: the feeding belt; middle: outlets of screen with two mesh sizes) (Source: MVW)

Picture 14: Example of a drum screen unit, inside view (with bag openers) (Source: Sutco RecyclingTechnik GmbH & Co. KG, Germany)

All fractions can be conveyed to further processing steps. The fines are commonly collected in containers and rejected. Typical features of a drum screen are listed in table 19.

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Chapter 5

5.7.3

Volatiles and ash

Volatiles and ash can be analysed from one sample according to the standard DIN 51719 [D-3] and DIN 51720 [D-4].

Volatiles (on the basis of DIN 51720 [D-4]): Approximately 1g of the sample is weighed to an accuracy of 0.0001g in a previously weighed quartz glass crucible. After closing the crucible lid the crucible is placed in an oven heated up to 900 ± 10°C. The oven is immediately closed once more and the chimney is switched on. After 7 minutes the crucible is taken out of the oven and placed in an exsiccator to cool down to room temperature (approximately 20 minutes). The crucible lid is removed and the cooled down crucible is reweighed to 0.0001g. The volatile constituents V(ad) are calculated as follows: % m1 m2 m3 W

= Weight of crucible after smouldering (g) = Weight of empty crucible (g) = Weight of crucible with sample (g) = Water content of the analysis-moist sample (%)

Ash (on the basis of DIN 51719 [D-3]): The crucible, with the residue after determination of the volatile constituents, is smouldered in the oven at 900 ± 10°C until weight constancy (approximately 5 hours). After cooling in the exsiccator (approximately 30 minutes) the crucible is reweighed exactly to 0.0001g accuracy (b). The ash content A(ad) is calculated as follows: % m1 = Weight of crucible with residues after smouldering (g) m2 = Weight of empty crucible (g)

5.7.4

Calorific value

The calorific value of a fuel describes the release of a certain heat amount during combustion. The calorific value differs depending on combustion conditions: Gross calorific value The quotient from the heat volume which is released on complete combustion and the

sample mass is designated as gross calorific value GCV (or sometimes named as upper heating value).

156


Qualitymanagement for alternative fuels Preconditions for this are: ƒƒ Combustion at constant volume ƒƒ Temperature of the fuel prior to combustion is 25°C ƒƒ Combustion products (CO2, SO2) are in the form of gas ƒƒ The water present in the fuel prior to combustion and the water formed during combustion of the hydrogen bearing compounds are in a liquid state post combustion In the net calorific value NCV the water formed post combustion is in gaseous form Net calorific value [D-7]. The NCV consists of the gross calorific value minus the condensation heat of water. Net calorific value NCV is vital for determination of fuels in cement or lime kilns as the condensation heat of the water cannot be utilised in the process management. The determination of the calorific value is one of the most important parameters for the evaluation of the suitability of alternative fuels. The determination is performed by means of a combustion calorimeter.

Picture 67: Example of a typical calorimeter (with calorimeter bomb and temperature control unit) for determination of calorific values (Source: MVW)

Analysis procedure (on the basis of DIN 51900-3 [D-8]) Approximately 1.0g of the fuel to be examined must be weighed to 0.0001g accuracy in a combustion crucible. Samples such as coal, animal meal and pet coke can be weighed in loose form in the combustion crucible. In the case of fluffy alternative fuels the preweighed ignition thread is channelled into the lower plate of the briquetting press and pressed with around 1g of the fine analysis sample. If no tablet can be pressed the sample is filled in loose form in a weighed acetobutyrate capsule and furnished with an ignition thread. The pressed tablet is weighed to 0.0001g accuracy and placed in the combustion crucible. The ignition thread is fixed to the ignition wire. 5ml distilled water are poured into the calorimeter bomb. The calorimeter bomb is filled with 30bar oxygen and placed in the calorimeter. After combustion the calorimeter bomb is unscrewed and rinsed with distilled water. Some drops of “mixed indicator 5” (manufacturer Merck) are added to the solution. Afterwards the solution is titrated with 0.1n caustic soda until the colour changes to green.

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Chapter 5

GCV: Gross calorific value (kJ/kg) C: Heat capacity of device (J/K) T: Increase of temperature (K) QNS: Consumption ml 0.1n NaOH (b) * 6 QZ: Ignition thread = 50J + ignition energy (70J), according to manufacturer data QS: Fuel sample weight * 10 * % sulphur (ad) * 5.7 If the sample is burned in a capsule the heating value of the capsule must be taken into consideration:

The lower heating value NCV (ad) is calculated as follows:

NCV: GCV: H2: w:

Net calorific value at constant pressure (kJ/kg) Gross calorific value (kJ/kg) Content of hydrogen (%) Content of inherent moisture (%)

Modified The German Institute for Quality Assurance and Certification published a modified proprocedure for NCV cedure for calculation of the net calorific values of alternative fuels [G-2]. determination of alternative fuels

The net calorific value is determined in accordance with DIN 51900 [D-7], whereby a correction due to nitrogen and sulphur (N,S-correction) is dispensed with on account of the very minor percentage influence of the N,S-correction on the overall correction as part of this quality monitoring.

GCV: C: T: QZ:

158

Gross calorific value (kJ/kg) Heat capacity of device (J/K) Increase of temperature (K) Sum of all heat quantities deriving from ignition wires, capsules, etc.


Qualitymanagement for alternative fuels The GCV is referred to dry state:

w: Content of inherent moisture (%)

In order to calculate the net calorific value, a correction is required due to the proportion Simplification of of water resulting from the hydrogen contained in the fuel sample during combustion NCV calculation and its evaporation enthalpy. In this context, an elementary analysis of the fuel would be necessary in each case. Due to the high number of samples and analytic effort involved in this, an instruction to find the hydrogen content â&#x20AC;&#x201C; and thus a H-correction â&#x20AC;&#x201C; described by DIN 51900 [D-7] is omitted. Taking into consideration a statistical evaluation of a large number of hydrogen analyses, a fixed correction factor of f = 0.92 has been introduced.

corresponds to

5.7.5

Chlorine

The determination of the chlorine content in alternative fuels is of great interest for Chlorine is one clinker and lime kiln operation regarding inner salt circulations and deposits or poten- of the most process relevant tial cloggings at ducts and cyclones. parameters

Analysis procedure (on the basis of DIN 51727 [D-6]) The sample is weighed according to the procedure described in chapter 5.7.4. The crucible is hung in the upper section of the calorimeter bomb (e.g. AOD bomb which has a catalytic surface coating, manufacturer IKA) with the sample and the ignition wire connected. 20ml 0.1n caustic soda and 1ml hydrogen peroxide 30% are filled as absorption solution into the calorimeter bomb. The bomb upper section is now placed in the bomb lower section and secured with the locking nut. The bomb is now filled with approximately 30bar oxygen. After combustion and cooling, the contents of the calorimeter bomb is rinsed with distilled Detection of water in a 400ml glass beaker (if only chloride has to be analysed) or into a volumetric flask chloride by red if chloride and sulphur have to be analysed. 10, 20 or 40ml 0.05n AgNO3 solution are added Fe(SCN)3 to the solution or to an aliquot of the volumetric flask (depending on the expected chloride content). Then around 5ml indicator solution (ammonium iron sulphate) are added to the solution. If a significant brownish colouring is evident, add as much indicator until weakened. The AgNO3 solution remaining after bonding of the chloride is titrated back with 0.1n NH4SCN solution until a weak reddish-brown colour becomes evident (process according to Volhard method). The chloride content is calculated as follows:

159


Alternative fuel and raw material (AFR) review “Straw”

Fact Sheet:

Alternative fuel and raw material (AFR) review “Straw”

1

Classification according to European waste Catalogue EWC

02

Wastes from agriculture, horticulture, aquaculture, forestry, hunting and fishing, food preparation and processing

02 01

Wastes from agriculture, horticulture, aquaculture, forestry, hunting and fishing

02 01 03

Plant-tissue waste

02 01 06

Animal faeces, urine and manure (including spoiled straw), effluent, collected separately and treated off-site

1.1

AFR description

Straw is an agricultural by-product. It is the dry stalk of a cereal plant, after the grain or seed has been removed. Straw makes up about half of the yield of cereal crops such as barley, oats, rice, rye and wheat. According to [V-1] straw also comprises dried leaves, dry stalks of cereal plants as well as fibreplants. Furthermore, the European Fuel Classification CEN/TS 14961 classifies straw as stalk and herb derived [A-1].

423


Fact Sheet

1.2

AFR pictures

2

AFR source and composition

2.1

Source

Picture 153: Loose straw (Source: MVW)

Picture 154: Straw baled and stacked (Source: MVW)

All kinds of straw derive from farming activities. Depending on the climate zone, wheat, rice or barley straw is produced. In several countries straw is simply burnt in the fields causing extensive air pollution. However, in other cases straw is pressed into square or round bales in order to use it as e.g. bedding material in farms and stables.

424


Alternative fuel and raw material (AFR) review “Straw”

2.2

Quantity and availability

Continent Europe

Asia Africa America Oceania World

2.3

Country France Russia Germany China India Turkey Indonesia Egypt USA Canada Argentina Australia

Wheat straw residues

Rice straw residues

[million tonnes] 47.8 32.3 23.8 132.0 79.2 25.2

[million tonnes]

7.4 83.3 29.3 12.1 26.1 709.2

231.5 146.6 55.5 6.6 9.8 1.6 673.3

Table 99: Quantities of straw 1999 (Source: [M-1])

Flow chart of AFR production

About site selection and planting Wheat straw production is similar to wheat grain production. As small grains do not stand in waterlogged conditions, a well-drained site should be selected. Seeding, as taking place in autumn, can be accomplished either by drilling or broadcasting, but drilling is the recommended method. Tillage options include conventional tillage, reduced tillage, and no-till [L-1]. About harvest and storage Wheat is typically harvested when the grain dries to the desired moisture content. Growers that are only interested in the straw might choose to harvest earlier. Some producers who raise small grains exclusively for straw will spray a herbicide to hasten drying down of the plants. Once cut, the straw should not be baled until it has completely dried [L-1]. According to [K-2] there are two basic approaches to the collection of field crop residues: 1. Collection of residue after crop harvested: Post-harvest concept 2. Simultaneous collection of crop and residue: Total harvest concept Focusing on rice straw the post-harvest collection of residues can be accomplished by the use of [K-2]: ƒƒ Conventional baling equipment to make two or three-wire rectangular bales ƒƒ Large round baling equipment ƒƒ “Big package” hay making equipment ƒƒ Buckrakes to make large piles of residue

425


Fact Sheet

ƒƒ Field cubing equipment ƒƒ Field chopping equipment [K-2] explains that according to the concept of total harvest straw and grain are removed in a single operation and then hauled to a designated location at the edge of the field. This can be the farmstead or the grain separation terminal. The main equipment needed for total harvest consists of a collector device, a stationary or modified combine, straw drying equipment and a large baler. The collected grain can be separated from the straw outside the field. The unthreshed rice for example is unloaded to form long, high piles. A combine with a modified feeding device works into these piles, threshing the rice and dropping the straw in an adjacent pile. An air duct beneath the straw pile lets natural or heated air to be blown through the pile to dry the straw [K-2]. It should be mentioned that harvesting shall avoid contamination with soil or other foreign particles. Collection and storage in dry, clean conditions, baling (for transport optimisation) is advised.

2.4

AFR composition

Straw mainly consists of cellulose, hemicelluloses and lignin. These organic compounds account for more than 80% of the dry matter of oats, barley and wheat straw [S-2]. Cellulose belongs to the group of high molecular polysaccharides, i.e. polymers of sugars. Cellulose consists of hexose molecules. The general chemical formula can be described by (C6H10O5)n. Hemicelluloses are a mixture of different high molecular polysaccarides (e.g. hexoses and pentoses). Lignin is a complex polymer based on phenlypropane as basic module which is connected to sugar molecules (pentoses). Furthermore, straw also contains small amounts of other organic compounds, such as proteins, waxes (they protect the epidermis of the straw) and sugars. Inorganic compounds are also present, for example salts and silica. In particular silica is blunt to cutting machinery and it reduces digestability. Silica also renders combustion more difficult. The chemical composition of straw depends on the soil type and fertiliser treatment [S-2]. Straw represents the major part of crop plants. The ratio between grain and straw is shown in the next table:

Crop residues

Table 100: Crop residues: Straw and grain ratios according to [B-1]

426

Rice straw Wheat straw Corn stalks Sorghum stalks Chickpea Pearl millet stalks

Grain/straw ratio 1 : 1.5 1 : 1.5 1 : 1.5 1 : 2.0 1 : 1.0 1 : 2.0


Alternative fuel and raw material (AFR) review “Straw”

2.5

AFR analysis

The next table shows the chemical composition of different kinds of straw:

Ash

Proteins

Hemicelluloses

Cellulose

Lignin

[%] dm

[%] dm

[%] dm

[%] dm

[%] dm

8.0 – 10.7

3.0 – 5.1

31 – 33

35 – 37

21

Straw type

Winter wheat* Barleys*

3.0 – 6.5

6.0 – 8.1

31 – 33

35 – 40

16 – 19

Oats*

3.9 – 6.4

1.9 – 4.5

29 – 32

33 – 38

18 – 19

Rice**

20

28

33

12

* according to [S-2], ** according to [S-1]

Table 101: Chemical composition of straw types (Source: [S-1], [S-2])

The proximate and ultimate analyses of straw are compiled in the next table:

Parameter

Ash Moisture Net calorific value C H N S Cl

Unit

Barley Wheat Wheat straw straw straw * * ** [%] dm 4.9 7.8 [%] [kJ/kg] 17,563 dm [%] dm 46.8 [%] dm 5.53 [%] dm 0.41 [%] dm 0.06 [%] dm 0.41

Rice straw * 19.1

10.2 18,028 45.5 6.12 0.52 0.13

Rice straw *** 20 50 – 801 10 – 152

Rice husks **

Hay **

39.2 4.8

44.5 6.3 0.9 0.6 0.1

45.9 6.0 2.3 0.3 1.0

14,920 45.7 5.7 0.5 0.3 0.7

38.9 4.74 1.37 0.11 0.47

1.9

* according to [E-1], ** according to [G-1], *** according to [S-1] 1 after harvest, ² field dry

Table 102: Ultimate and proximate analyses of different straw types (Source: [E-1], [G-1], [S-1])

It should be noted that straw contains considerable amounts of chlorine which is an important factor for kiln operation regarding evolution of circulating salts and therefore of the tendency for coatings.

427


Fact Sheet

2.6

Table 103: Ash composition of straw (Source: [E-1], [S-1])

AFR ash composition

Parameter

Unit

CO2

[%]

Barley straw * 0.6

Wheat straw *

Rice straw * 0.7

SO3

[%]

0.9

4

Cl

[%]

2.3

5.6

P2O5

[%]

1.2

3.2

SiO2

[%]

59.4

52

73

Fe2O3

[%]

0.2

1.1

0.6

Rice straw **

1.4

Al2O3

[%]

0.4

0.6

1.4

CaO

[%]

5.1

9.2

1.9

65.7

1.7

MgO

[%]

0.8

1.8

1.8

2.1

Na2O

[%]

0.3

0.3

0.4

3.1

K2O

[%]

5.6

21.9

13.5

15

Pb

mg/kg

8

Cd

mg/kg

Cu

mg/kg

Hg

mg/kg

57

* according to [E-1], ** according to [S-1]

As can be seen the ash composition of straw is dominated by silica. Higher amounts of alkalis can be apparent.

3

Harmful substances and hazardous characteristics

From its origin, straw does not contain harmful substances at all. Depending on the production facility, the possibility is given of mixing or contamination of straw with other substances used in the production facility. Dust generation is possible during the processing of straw owing to the fine grain size. Workers or employees should use a dust mask. Generally, local regulations regarding health and safety should be adhered to.

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Alternative Fuels and Raw Materials Handbook, Volume 1