Pulp and Paper Canada May / June 2010

May/June 2010

www.pulpandpapercanada.com

Focus on Biorefining Walk Through Kruger’s Biomass-to-Syngas Process Integrating Pulp Mills with Biorefining Experts Rank the Barriers to Biorefining JOURNAL OF RECORD, PULP AND PAPER TECHNICAL ASSOCIATION OF CANADA COHEN: Analysis of Biorefinery Technologies for Ethanol Production

Water is the connection You can’t make paper without water and at Kemira, we know both. Built on our expertise in water quality and quantity management (WQQM) and fiber chemistry, we offer a complete product portfolio designed to provide value for our customers. Our solutions not only improve your paper quality and processes, but also help you to make better use of scarce resources like water, energy and fibers.

From pulp to paper, water is the connection.

www.kemira.com 1380 County Rd. No 2 Maitland, Ontario, Canada K0E 1P0 613 348 7711 Kemira, 1950 Vaughn Road,+ Kennesaw, GA 30144, Tel. 800-347-1542 www.kemira.com

Photo: Grant Harder Photography

www.pulpandpapercanada.com

MAY/JUNE 2010 Vol. 111, No. 3 PRINT EDITION ISSN 0381-548X

A Business Information Group Publication ON-LINE EDITION ISSN 1923-3396

FOCUS ON BIOREFINING

9 10 13

Technology and Policy Driving Biofuels Growth Biorefining processes have been proven to be technically feasible, but are they economically sustainable?

KRUGER BIOMASS VENTURE

10

Kruger’s Biomass-to-Syngas Venture Pays Off A tissue mill’s foray into the uncharted waters of biomass gasification for steam production is a success. Now it is time to assess the costs — financial and environmental.

Drivers and Barriers for Implementation of the Biorefinery An expert panel concludes that the appeal of biorefining is its potential for short- and long-term financial gain, while uncertainty about the technology is its largest drawback.

ONTARIO TENURE REFORM

6

FORTRESS PAPER

8

TECHNICAL PAPERS

18

PAPTAC abstracts A brief introduction to some of the technical papers available from the Pulp and Paper Technical Association of Canada at www.paptac.ca.

19 Simulation of a Kraft Pulp Mill for the Integration of Biorefinery

Technologies and Energy Optimization The objective of the simulation is to supply data for energy and water studies and to analyze the implementation of biorefining technologies.

By E. Mateos-Espejel, M. Marinova, S. Schneider, and J. Paris (École Polytechnique de Montréal)

24 Critical Analysis of Emerging Forest Biorefinery (FBR) Technologies for Ethanol Production The paper aims to define and weigh critical metrics for evaluating forest biorefinery technologies for bioethanol production. Thermochemical process routes were generally favored for ethanol production by the panelists

By J. Cohen, M. Janssen, V. Chambost and P. Stuart (NSERC Environmental Design Engineering Chair in Process Integration, École Polytechnique – Montréal)

31

Analysis of a Biorefinery Integration in a Bisulfite Pulp Process Particular attention was paid to the integration of the chemical recycling loops which influence the choice of biorefinery integration strategies.

By Z. Périn-Levasseur (Natural Resources Canada, CanmetENERGY), F. Maréchal (Ecole Polytechnique Fédérale de Lausanne), and J. Paris (Ecole Polytechnique de Montréal) contents continue on page 4

pulpandpapercanada.com

IN EVERY ISSUE

4 6, 8, 42

23

44

45

Editorial News Events Technology News Classified Ads

MISSION STATEMENT:

To promote the pulp and paper industry in Canada by publishing news of the people and their innovations in research, technology, management and financing, as well as forecasts of future trends.

Authorized to publish papers of the Pulp and Paper Technical Association of Canada, which are identified by the symbol Serving the industry since 1903.

May/June 2010 PULP & PAPER CANADA

3

EDITORIAL

Got anything to say about that?

T

he Pulp & Paper Canada web site has a new look. But what’s exciting to me is what’s beneath the surface.

Changes to the underlying architecture of the site have given us new features that make it easier to communicate with me, and with others in the industry.

The newer technology now allows readers to post comments related to each article, which, I think, can really enhance and add to a story. Good comments help to put things in perspective. For example, someone who worked at the Tembec Pine Falls mill, which is now closed, commented on a recent story about union concessions at AbitibiBowater mills in Eastern Canada.

He says, “I’d like to remind Mr. Coles that a 10% wage cut with the pensions intact, along with future wage increases, is nothing more than a minor inconvenience for the workers involved. Workers at the Tembec Pine Falls mill have lost their jobs and pensions — now that is a huge setback.”

This kind of comment can spark an informed discussion, and leave us with a richer story. Please, feel free to comment on any stories that appear on the Pulp & Paper Canada web site. Let’s make it a two-way conversation, not just me and my staff speaking to the readers across Canada.

We do ask that you make your comments relevant to the article, not overtly promotional, and not derogatory of other people. We do offer online classified ads, so I won’t approve comments that offer to buy or sell items.

With travel restrictions and shutdowns, the opportunities to attend networking events and socialize with workers from other mills are diminishing. But forums such as Pulp & Paper Canada’s web site, and the initiatives PAPTAC is taking with online communities, give all of us who are currently in the industry, and those who were formerly employed in the industry, a chance to make our views known. I’m no longer the only one with the power to share my opinions with thousands of readers.

Cindy Macdonald, Editor

contents continued from page 3

34 Energy Implications of Water Reduction

Strategies in Kraft Process. Part I: Methodology The methodology can be used to find appropriate strategies for water consumption reduction and also considers their impacts on the thermal energy efficiency of the process.

By E. Mateos-Espejel, M. Marinova, S. Bararpour and J. Paris (École Polytechnique, Montréal)

38 Energy Implications of Water Reduction

Strategies in Kraft Process. Part II: Results A case study analyzes four strategies that simultaneously reduce water, steam and cooling requirements.

By E. Mateos-Espejel, M. Marinova, S. Bararpour and J. Paris (École Polytechnique, Montréal)

4

PULP & PAPER CANADA May/June 2010

EDITORIAL Editor CINDY MACDONALD 416-510-6755 cindy@pulpandpapercanada.com Contributing Editors HEATHER LYNCH

Sustaining member, Pulp and Paper Technical Association of Canada; Member, Canadian Business Press and Audit Bureau of Circulation.

ADVISORY BOARD Richard Foucault Greg Hay Dr. Richard Kerekes Barbara van Lierop Dr. David McDonald Dennis McNinch Dr. Yonghao Ni Bryant Prosser Dr. Paul Stuart Ross Williams

Indexed by: Canadian Business Periodicals Index; Abstract Bulletin, The Institute of Paper Science and Technology; Materials Science Citation Index PULP & PAPER CANADA (ISSN 0316-4004) is published by BIG Magazines LP, a div. of Glacier BIG Holdings Company Ltd., 12 Concorde Place, Suite 800, Toronto, ON, M3C 4J2.

ADMINISTRATION Publisher JOHN SIMMONS jsimmons@pulpandpapercanada.com President, Business Information Group BRUCE CREIGHTON Vice President, Publishing ALEX PAPANOU EDITORIAL AND SALES OFFICES: 12 Concorde Place, Suite 800 Toronto, ON M3C 4J2 Phone: 416-442-5600.

Toll Free: c da 800-268-7742; usa 800-387-0273 PRODUCTION Art Director RON TAYLOR rtaylor@bizinfogroup.ca

SUBSCRIPTION RATES: Canada – $90Cdn/1 year; $133Cdn/2 yrs.

U.S. – $95US/1 year.

All other countries – $200US/1 year. Single copies $19.50. Air Mail: $96 extra (Cdn $ in Canada; US $ other)/1 year; Single copies: $8 (by airmail) per issue extra (As above).

(All subscription prices exclusive of taxes.)

The editors have made every reasonable effort to provide accurate and authoritative information but they assume no liability for the accuracy or completeness of the text or its fitness for any particular purpose.

All rights reserved. The contents of this publication may not be reproduced in part or in full without the consent of the copyright owner.

From time to time, we make our subscription list available to select companies and organizations whose product or service may interest you. If you do not wish your contact information to be made available, please contact us via one of the following methods.

Phone: 1-800-668-2374; fax: 416-442-2191; e-mail: privacyofficer@businessinformationgroup.ca; mail to: Privacy Officer, Business Information Group, 800-12 Concorde Place, Toronto, ON, M3C 4J2 Canada

Circulation Manager CINDI HOLDER cholder@bizinfogroup.ca Market Production Manager KIMBERLY COLLINS kcollins@bizinfogroup.ca Print Production Manager PHYLLIS WRIGHT pwright@bizinfogroup.ca Reprint requests: Marisa Sementilli 416-510-6829 News and Press Releases media@pulpandpapercanada.com SALES REPRESENTATION North America: John Simmons, Publisher, Phone: 416-510-5142, Fax: 905-666-0778, jsimmons@pulpandpapercanada.com Inside Sales and Classified Ads: Jim Bussiere, Senior Account Manager, Phone: 416-442-5600, ext. 3606, Fax: 416-510-5140, jim@pulpandpapercanada.com Scandinavia and Finland: Jyri Virmalainen, Exomedia Oy, Latokartanontie 7A, 4 krs, 00700, Helsinki, Finland; Phone: +358-9-61500100; Telex 121394 tltx sf (Att: Exomedia); Fax 358-9-61500106.

E-mail: jyri.virmalainen@exomedia.fi

POSTMASTER: Please forward 29B and 67B to 12 Concorde Place, Suite 800, Toronto, ON M3C 4J2. Legal deposit Quebec National Library. Canada Post Publications Product Agreement No. 40069240. Publications Mail Registration No. 09777. USPS 751630. US office of publication: 2424 Niagara Falls Blvd., Niagara Falls, NY 14304-5709.

Periodicals Postage paid at Niagara Falls, NY. US POSTMASTER: Send address changes to Pulp & Paper Canada, 2424 Niagara Falls Blvd., Niagara Falls, NY 14304. Printed in Canada. Return undeliverable Canadian addresses to Circulation Dept. – Pulp & Paper Canada, 800-12 Concorde Place, Toronto, ON, M3C 4J2.

Canada Post Canadian Publications Mail Agreement #40069240 PAP Reg. No. 09777 A Business Information Group Publication Print edition ISSN 0381-548X On-line edition ISSN 1923-3396

We acknowledge the financial support of the Government of Canada through the Publications Assistance Program towards our mailing costs.

pulpandpapercanada.com

Metso and Tamfelt join together The union brings together two world-class suppliers, both dedicated to providing real results for the pulp and paper industry through advanced, cost-effective and sustainable solutions. www.metso.com/fabrics

INDUSTRY NEWS Paper Excellence acquires Mackenzie pulp mill

The Mackenzie pulp mill is expected to reopen in the fall, under the ownership of Netherlands-based Paper Excellence.

MACKENZIE, B.C. — The Mackenzie pulp mill in British Columbia has been acquired by Paper Excellence B.V., a business unit of Indonesia’s Sinar Mas. The transaction secures the future of the mill, which is expected to resume production of NBSK pulp in the fall. Reuters reports that Paper Excellence paid $20 million for the mill, and will invest $30 to $40 million to restart it.

This mill is the Paper Excellence Group’s second acquisition in Canada.

It also owns and operates a pulp mill in Meadow Lake, Saskatchewan.

It took a concerted effort by a number of organizations and groups to get the mill to the point where it could resume production. Team Mackenzie of the Mackenzie Pulp Mill Development Corporation preserved the capacity of the mill to resume production. The provincial government worked with the District of Mackenzie to consolidate and reduce the debt of the mill. B.C. Community and Rural Development Minister Bill Bennett thanked public servants in the Rural BC Secretariat for the instrumental role they played in crafting a deal that will ensure hundreds of people in Mackenzie can head back to work.

The McLeod Lake Indian Band worked with the Ministry of Forests and Range to help secure the fibre needed to start the mill. Also important was the negotiation of a new collective agreement with the Communications, Energy and Paperworkers Union (CEP). The agreement preserves wages, benefits and pensions, while enabling the mill to reopen with significant cost reductions.

Fraser Papers exits Canadian scene after six years

TORONTO — Fraser Papers has completed the sale of its two Canadian mills, located at Thurso, Que. and Edmunston, N.B., in two separate transactions, leaving the insolvent paper company with no Canadian pulp and paper operations.

The Thurso mill was sold to Fortress Paper (see page 8 for details). The Edmunston facility was sold as part of the specialty papers business, along with a mill in Madawaska, Maine, and two New Brunswick sawmills, to Twin Rivers Paper Company. Twin Rivers was formed by creditors of Fraser Papers.

Once Fraser Papers sells its remaining U.S. assets, the company will use the proceeds to settle the remaining secured claims, prior to distributing any remaining proceeds to unsecured creditors.

Fraser Papers was formed in 2004, from some assets of Norbord.

AbitibiBowater seeks permission to sell four closed mills, machinery

MONTREAL — Newsprint producer AbitibiBowater is asking the bankruptcy courts for approval to sell four closed mills and their machinery to Montreal-based American Iron & Metal, according to a Canadian Press news report on April 19.

The scrap metal company would buy the assets for $8.7 million. The deal includes the mills at Beaupré, Que., Donnacona, Que., Thunder Bay, Ont., and Dalhousie, N.B. CP reports that American Iron would also pay AbitibiBowater 40% of the money raised from the sale of the paper machines. Even if they are sold for scrap, American Iron would pay at least $5 million.

The metals company would assume all environmental liabilities associated with the closed mills. The company has said it’s open to ideas to reuse the vacant mills, but one condition set by AbitibiBowater

Ontario reveals proposal for forest tenure reform TORONTO — The Ontario government has released its proposed framework for modernizing the province’s forest tenure and pricing system. The cornerstone of the new system is the introduction of Local Forest Management Corporations (LFMCs) to manage Crown forests and oversee the competitive sale of Crown timber.

“The proposed new system would be flexible, transparent, and responsive to changing social, economic and environmental conditions and needs,” says Michael Gravelle, Minister of Northern Development, Mines and Forestry. The framework contains a proposal for five to 15 new LFMCs that would assume responsibility for management, marketing and sale of wood from Crown forests within their defined area.

According to the outline, the LFMCs are intended to stimulate competition in selling Crown timber.

LFMCs are envisioned to be financially self-sufficient, managed by a board of directors. Net earnings of the LFMCs would be reinvested in the forest and paid as dividends to the government.

Timber sold by the LFMC could either be harvested by the LFMC itself,

Michael Gravelle, Ontario’s Minister of Northern Development, Mines and Forestry, introduced the forest tenure reform package in Thunder Bay.

harvested and delivered by an entity operating under contract, or harvested by the buyers or for the buyers by entities operating under forest resource licences. Day-to-day activities of the LFMC would be directed by a general manager.

It is proposed that at least 25% of the wood supply in each management area be sold through tendered sales. The price from tendered sales would guide the prices for other negotiated sales. An information system to track the pricing information is suggested.

The proposal is available at www.ontarioforesttenure.ca; comments are welcome.

… FPAC UPDATES INDUSTRY GUIDANCE FOR REPORTING GHG EMISSIONS … BANKS URGED TO ADOPT GUIDANCE TOOL TO ASSESS FORESTRY INV s s s

6

PULP & PAPER CANADA May/June 2010

pulpandpapercanada.com

INDUSTRY NEWS is that the locations not be used to produce paper.

American Iron’s owner Herbert Black told CP the buildings may be scrapped for their metal value, and some of the paper machines may suffer the same fate.

AbitibiBowater is also looking to sell three closed mills in Quebec. The mills in Roberval, Saint-Fulgence and Lebel-surQuevillon have been closed since last year.

North America’s largest newsprint producer hopes to exit court protection from creditors in Canada and the United States by autumn.

Union, AbitibiBowater reach deal for Eastern mills

OTTAWA — Workers at AbitibiBowater pulp and paper mills in Eastern Canada have voted to approve a new collective agreement that includes cost reductions for the company and wage reductions, but protects pensions for retirees and workers.

“Our members have voted to protect retirees and pensions, and to bring this company out of bankruptcy protection,” said Communications, Energy and Paperworkers Union of Canada national president Dave Coles.

The five-year agreement is conditional on government approval in Québec and Ontario. Running until 2014, it maintains all current pensions and accrued pension service, but also includes a new jointly managed pension plan with 10% employer contributions for future service.

The agreement also includes a 10% wage reduction with wage increases resuming in 2012 and 2013.

The agreement covers about 3,000 CEP members in 18 local unions.

Catalyst settles tax battle with one city, escalates court action to Supreme Court

Catalyst Paper will seek leave to appeal to the Supreme Court of Canada, following dismissal of its appeal concerning the North Cowichan 2009 tax bylaw by the Court of Appeal for British Columbia. In its April 22nd decision, the Appeal Court declined to strike down the tax bylaw while calling the “extreme imbalance” perpetuated by the District of North Cowichan a political problem requiring a

policy decision by elected officials.

In the meantime, Catalyst Paper and the City of Powell River have inked an agreement in principle to achieve the twin objectives of reducing the Class 4 property tax rate paid by the company’s Powell River mill while assisting the city in reducing significantly its capital expenditures for future municipal service infrastructure.

The deal will see Catalyst’s annual property taxes capped at $2.25 million, and Catalyst providing waste treatment services for the municipality.

The agreement follows months of disputes between Catalyst Paper and the B.C. municipalities in which it operates.

Catalyst withheld its municipal taxes in 2009, and challenged the property tax rates of four municipalities in court. The B.C. Supreme Court ruled in all four cases in favour of the cities. Port Alberni later

BRIEFLY

launched legal action against Catalyst to collect the unpaid taxes plus interest.

STOPS, STARTS, CHANGES Catalyst Paper restarted the second line of pulp production at its Crofton, B.C., NBSK mill in early May, taking advantage of a stronger market.

“We have adequate fibre supply and sales to support the additional volume which allows us to take advantage of the current uptick in pricing,” said Richard Garneau, president and CEO. “We’ll run as long as the economics are positive and will be keeping a very close watch on the order file and inventory levels.”

The restart of Crofton’s second line of production will add 165,000 tonnes of pulp capacity on an annualized basis. All Crofton pulp mill employees who are currently on layoff will be recalled.

Fortress Paper Ltd. has signed an energy supply agreement with Hydro Quebec for the sale of green electricity to be produced at the company’s Thurso, Que., mill upon completion of a biomass-based cogeneration facility.

Under the agreement, the company will construct a cogeneration facility to provide net 18.8 megawatts of green power to Hydro Quebec over a 15-year term. Deliveries are expected to begin in the fourth quarter of 2012.

of 50 MW. The plant will utilize wood, wood waste and wood shavings to produce electricity.

Canfor Pulp Income Fund has received unitholder and court approvals to convert to a dividend-paying public corporation named Canfor Pulp Products Inc.

Industrial chemist George H. Tomlinson II passed away in March at the age of 97. Dr. Tomlinson worked briefly at McGill University before joining Howard Smith Chemicals. He remained with Howard Smith and its successor companies, including Domtar. He became director of research for Domtar in 1961, and then v-p of research and environmental technology. Dr. Tomlinson became an honorary life member of CPPA (now PAPTAC) in 1980.

He was also a TAPPI Gold Medalist and TAPPI Fellow. He is known for his work with lignin and black liquor oxidation.

See News, page 42

We Energies, Milwaukee, Wisconsin, has awarded Pöyry the engineering contract for a EUR 185-million capital project for a new 50 MW biomass cogeneration plant to be constructed at the Domtar paper mill facility in Rothschild, Wisconsin.

The new cogeneration facility will be designed to provide steam to the Domtar paper mill and is capable of providing a nominal power generation

Metso has acquired the Viconsys web inspection and web break system business. The acquisition enhances Metso’s automation product and service offering to the paper industry. Viconsys is known as an industry benchmark and global market leader in machine vision technology.

VESTMENTS … NEWFOUNDLAND LOSES LEGAL BATTLE WITH ABITIBIBOWATER OVER CLEAN-UP … DOMTAR TO SELL LUMBER BUSINESS TO EACO s s s pulpandpapercanada.com

May/June 2010 PULP & PAPER CANADA

7

INDUSTRY NEWS

Thurso’s Future Secure

with Fortress

There’s a new kid on the block and he’s playing by a different set of rules. Brimming with confidence, enthusiasm, and steadfast resolution to succeed, Fortress Paper offers a fresh perspective for Canada’s

By Heather Lynch pulp and paper sector.

W

ith its recent acquisition of the idled Thurso pulp mill located in the Outaouais region of western Quebec, Vancouver-based Fortress Paper plans not only to make a splash on the market, but a significant profit, too. By ditching the production of northern bleached hardwood kraft pulp in favour of manufacturing dissolving pulp, the company is confident it won’t fall prey to the relentless profit losses so many Canadian forestry companies have witnessed.

“We’re expecting to generate $60 million (EBITDA) but could potentially see profits in the order of $200 million,” says Chad Wasilenkoff, president and CEO of Fortress Paper, with a confidence not often heard in this industry.

Wasilenkoff refers to himself as a “contrarian” investor, as he keeps a punctilious eye on industries widely considered to be depressed, only to pounce on opportunities to grab world class assets at heftily discounted prices. For his $3 million* purchase price, Wasilenkoff pocketed $85 million worth of assets in buying the Thurso facility from insolvent Fraser Papers.

Fortress Paper currently owns and operates two pulp mills in Europe — in Germany and Switzerland. With an emphasis on specialty papers, the company’s product portfolio includes nonwoven wallpaper base products, graphic papers, and technical papers. Fortress officially incorporated in 2006, with the intention of taking a closer look at investments in the forestry sector. The company was not specifically seeking to invest in Canada, but had been observing the dissolving pulp market for a number of years. When the Thurso pulp mill came on the market, the timing and price were compelling.

8

PULP & PAPER CANADA May/June 2010

An injection of cash and enthusiasm will see the Thurso, Que., NBHK pulp mill converted to dissolving pulp, and the addition of biomass-based cogeneration capability.

The acquisition is also welcome news to the 320 people formerly employed by the mill, who will, with only a few minor exceptions, be back on the job in June 2010.

“The Quebec government was very interested in getting people back to work,” Wasilenkoff confirmed. “We were informed that not only does the mill provide work for 320 people, but an additional 2900 indirect jobs are supported by the operation, as well.” The provincial government’s motivation to see the facility up and running translated to a cash infusion of $102 million, in the form of a 10-year loan.

It’s money that Wasilenkoff anticipates no difficultly in repaying. “We’re extremely comfortable with the underlying fundamentals,” he says, explaining the overall growth in the market his newly purposed mill will be supplying. “Asia will be our biggest market, and the textile

industry there is very strong. As more and more people move into middle income brackets, research indicates consumption of clothing increases, and yet, cotton is an expensive material to produce. Rayon has very similar characteristics to cotton but is more absorbent and breathable, and is less expensive to produce. As a result, the finished product almost always trades at a premium compared to cotton. We consider this to be a very, very low-risk and high-return venture.”

Fortress has two additional multimillion dollar goodies in its bag: the company is entitled to $10 million from the federal Green Transformation Program, as well as $15 million from the Green Infrastructure Fund. Both are initiatives designed to encourage green energy generation and environmentally-friendly production upgrades. Fortress’ decision to construct a biomass-based cogeneration See Thurso, page 42 pulpandpapercanada.com

MARKET OUTLOOK

Technology and Policy Driving Biofuels Growth Biorefining processes have been proven to be technically feasible, but are they economically sustainable?

B C M, E

I

magine that it’s 2021, and you’re flying to a town in the B.C. Interior. You pass over a large industrial facility that looks a lot like a kraft pulp mill, but with subtle differences. What you’re seeing is a biorefinery, maybe producing kraft pulp, maybe producing ethanol, definitely producing biomass-derived chemicals.

It’s not a far-fetched vision. Various technologies that could be the foundation for such a mill are operating today at the pre-commercial or demonstration level, and government policy is actively encouraging the development of renewable fuels, such as cellulosic ethanol.

Almost all biofuels produced today are first-generation biofuels, based on food feedstocks, and using biochemical processes. So-called second generation biofuels, such as cellulosic ethanol, are not yet commercial, but the first commercial plants are expected within the next few years.

“We all know that the technology will work,” says Ross MacLachlan, president and CEO of Lignol Energy Corp. “It’s all about the cost point.” Lignol currently has a pilot plant in Burnaby, B.C. to demonstrate its technology for refining cellulosic biomass into fuel grade ethanol and specialty chemicals.

Ambitious targets push development

Public policy in many jurisdictions favors the replacement of fossil fuels with renewable alternatives. “The targets being set are ambitious, and that’s good,” says UBC’s Dean of Forestry, Jack Saddler.

“The U.S. has a defined target for celpulpandpapercanada.com

lulosic biofuels. It will not meet that target, not because of cost constraints, but because the technology is not yet advanced enough.”

Saddler expects the development of a wood-based biofuel industry to proceed along a similar timeline as corn ethanol, which suggests it will be about 10 years before the industry is fully commercial.

Gurminder Minhas, Lignol’s director of technology deployment, points to the American renewable fuel targets to illustrate the market potential for cellulosic ethanol. The U.S. target is 36 billion gallons of renewable fuel in the transportation infrastructure by 2022. It is estimated that corn ethanol will be able to account for 12-15 billion gallons. “They’re looking to cellulosic ethanol to fill that gap,” says Minhas.

Closer to home, Minhas explains that with B.C.’s current target of 5% ethanol blended in gasoline by 2010, the province would need 300,000 to 350,000 L per year of ethanol. A Lignol biorefinery processing 1000 tonnes per day of biomass is similar in size and scope to a mid-size pulp mill, and would produce roughly 100,000 L per year of ethanol. So in B.C. alone, three second-generation cellulosic biofuel facilities would be needed to meet the province’s domestic demand.

The best path is not so clear

One expert at a bioenergy event in Nova Scotia in February noted that technical barriers remain for second-generation biofuel production. “There is no clear candidate for “best technology pathway” between the competing biochemical and

thermo-chemical routes,” stated Warren Mabee, director of Queens University’s Institute for Energy and Environmental Policy.

But UBC’s Saddler says consensus on the best path forward is emerging.

“It is becoming clearer which technology suits which feedstocks, and which circumstances.” For example, he notes that a kraft mill should probably consider gasification technology, whereas Iogen’s technology is emerging as best suited to wheat straw feedstock.

“For biofuels, what’s going to evolve is a central facility that makes a range of products,” says Saddler. Work in his research group points to a facility that looks a lot like a kraft pulp mill.

This is, in part, because of the logistics of shipping wood chips. It will likely be more economical to ship the finished products, such as ethanol and chemicals, because of their higher value.

In general, says Minhas, a biorefinery needs to be close to the source of biomass.

“Ethanol is energy-dense, so it’s relatively inexpensive to transport. Specialty chemicals have higher value so they too are worth the transportation.”

There is an opportunity, over the next decade, for forest companies to participate in the burgeoning biofuels sector.

But the road to ethanol production is not a superhighway. Each participant will have to map our their own route.

“We are ready to deploy, if we had mature partners who understand plant operations, the chemical industry, and the energy sector,” says MacLachlan. “That would be a powerful consortium.” PPC May/June 2010

PULP & PAPER CANADA

9

COVER STORY

Kruger’s Biomass-to-Syngas Venture Pays Off B C M, 

K

Chuck Stewart, general manager of Kruger Products’ Western Region (left) and Frank van Biesen, vice-president, technology for Kruger Products, at the biomass infeed station.

10

PULP & PAPER CANADA May/June 2010

ruger Products’ foray into the uncharted waters of biomass gasification for steam production is a success. The system has been operating for about six months, and is supplying about half the steam required by the tissue mill in New Westminster, B.C. Now it is time to assess the costs — financial and environmental.

The Kruger team chose biomass gasification to replace a temporary natural gas boiler because of the technology’s low emissions, its use of a renewable fuel, and the lower fuel cost compared with natural gas.

Gasification of biomass is a relatively new technology, although the principle of gasification has been used for decades with coal. “It’s a complex thermo-chemical process within an automated, simple mechanical process,” says Jonathan Rhone, president and CEO of Nexterra Systems Corp., the B.C.-based company which supplied the gasification system for Kruger Products. “We’re really focusing on developing rock-solid technology, that meets reliability and cost targets,” he notes. “We focused on heating applications first, to complete our learning about the gasification process.”

This Kruger project is the first installation of a Nexterra gasification system that direct-fires syngas, derived from wood, into industrial process boilers.

There are several opportunities for biomass-to-syngas systems in pulp and paper mills.

Syngas could replace fuel-oil or natural gas to fire lime kilns at kraft mills. And, as has been shown at this tissue mill, it can be used to replace hog fuel boilers or natural gas boilers to produce process steam. pulpandpapercanada.com

COVER STORY How it works: Biomass to syngas to steam

At the heart of Kruger’s biomass gasification system are two 35-ft. high, 16-ft. diameter gasifiers.

Biomass is trucked to the plant, at a rate of about six truckloads per day. Live-bottom trucks unload into a large, covered storage bin, refurbished from the days when Kruger had a hog fuel boiler at this plant. The bin holds about four days of supply.

From there, the biomass travels by covered conveyor across a road, across railroad tracks, along the roof of the plant to the gasifiers on the other side. There it drops into two metering bins, one for each gasifier. The metering bins discharge to twinscrew feeders, which vary the output to the gasifier chamber.

Within the gasifier, the temperature in the bed at the bottom ranges from 1500 to 1900°F. The air supplied to the gasifier is carefully controlled, so that only a small portion of the fuel combusts completely. The process produces enough heat to pyrolyze and chemically break down the balance of the fuel into a cleanburning, synthetic, combustible gas commonly called “syngas”.

As the syngas rises to the top, it cools to about 600°F, where it exits through a duct.

Ductwork carries the syngas from both gasifiers to a single ignition chamber, where it is mixed with air and ignites. The combusted syngas is direct-fired to the boiler.

Gases exit the boiler through the economizer, and then proceed through the economizer to the ID fan and the electrostatic precipitator. Particulate matter from the precipitator joins the ash disposal system, while carbon dioxide, nitrogen and water vapor are released to the atmosphere.

Ash is collected at the bottom of the gasification vessels, conveyed to a covered bin, and periodically trucked away for disposal.

With two gasifiers, the system is capable of producing 40,000 lb/hr of steam. It currently provides about half of the plant’s needs. The rest is provided by natural-gas fired boilers.

Control and monitoring of the gasification system is integrated into the plant’s distributed control system.

In addition, lifecycle costs are generally lower than typical wood combustion systems.

Kruger’s system has been operating for about six months now. As part of the funding package granted to the project by federal and provincial governments, research institute FPInnovations will monitor and evaluate the installation.

“In terms of heat, it is producing about 5-10% beyond expectations, and they haven’t even begun optimization,” says Jim Dangerfield, executive vice-president of FPInnovations.

Once the system is optimized, FPInnovations will gather performance data, operating data, and data related to the system’s environmental footprint. “We have all our baseline data, which was gathered before the old system was shut down,” Dangerfield explains.

“My sense of it so far, is that there are mills where this technology could potentially be used. I don’t see any reason why most of these couldn’t use it, but it will come down to the hard economic facts.”

One advantage that Nexterra technology has over conventional combustion is its much lower air emissions. Particulate emissions can be equivalent to natural gas. NOx emissions can be 30 – 40% lower that conventional combustion of wood, and both VOC and CO emissions are both lower than those produced by conventional wood combustion or by burning natural gas. “That’s what allows us to operate in urban areas and help our customers secure air permits and community acceptance,” Rhone notes. pulpandpapercanada.com

All photography: Grant Harder Photography

Gasification proves to be clean and efficient

Stewart and van Biesen in front of one of Kruger’s two gasifiers. The vessels at the heart of the gasification process each measure 16 ft. in diameter and about 35 ft. in height.

May/June 2010

PULP & PAPER CANADA

11

COVER STORY Biomass is not the easy way out

construction site is sandwiched between the wall of the existThere’s no doubt that a thermo-chemical/mechanical biomass ing building and the river. An access road also runs along the gasification system is more complicated to operate than a natural riverfront so the installation team had to be very careful not to gas boiler. But the indisputable fact is that biomass is cheaper disrupt mill traffic for lengthy periods. than natural gas, and will be for the foreseeable future, so “we’ll The construction phase took about 6 months. Overall, the put up with complexity to get some cost reduction,” says Frank project wrapped up on time and on budget, and the gasification van Biesen, vice-president, technology for Kruger Products. Van unit began production in December 2009. “It started up almost Biesen is a strong advocate of the gasification project. transparently. We reached target steam output within a week,” Another driver for the adoption of biomass instead of natural van Biesen recalls. He says the price tag for the Nexterra porgas is concern over the company’s carbon footprint. While for tion of the project was about $5 million. The original estimated many companies, “carbon footROI was 3 to 3-1/2 years, but print” is a feel-good marketing natural gas prices have dropped “I don’t see any reason why most measure, in B.C., carbon has mills couldn’t use it, but it will come since then. a price tag. The province has Van Biesen says he’s happy down to the hard economic facts.” a carbon emission tax, so the with the performance of the – Jim Dangerfield, FPInnovations switch to carbon-neutral biosystem, although there are still mass will have a direct positive a few wrinkles to be worked out. affect on the bottom line. The tax savings for Kruger Products One of the problems in these early months of operation has in 2010 will be about $380,000. been premature wear on some components of the biomass feed The tight confines of Kruger’s New Westminster site cre- system. Another is the unexpected formation of clinkers (inorated some construction challenges. The mill houses four paper ganic materials that melt and fuse together before cooling to machines and 19 converting units, plus a small groundwood form a solid chunk) that can foul the ash collection system. Both plant, and is a major distribution centre for Kruger Products’ of these issues are being resolved through cooperation between tissue brands in western Canada. It is hemmed in by a river, a the Kruger and Nexterra. busy set of railroad tracks, and the urban sprawl of a Vancouver “Kruger’s been a fantastic partner,” says Nexterra CEO Jonasuburb. than Rhone. “They are one of the most technically savvy orga“Space was definitely an issue,” recalls van Biesen. The nizations we’ve worked with. That was an unexpected benefit.

“One thing we really appreciated is that they were prepared to be an early adopter of a new technology.”

Does it measure up?

Various government programs have contributed funding to the biomass gasification project, which mitigates some of the risk for Kruger. Rhone says FPInnovations played a role by galvanizing all the parties around the project.

The research organization will also have a role as a thirdparty observer, monitoring and measuring the process to asses its suitability for other pulp and paper facilities. FPInnovations will also offer tours of the gasification site and disseminate information to the industry.

“Our role is to gather information, to provide third party independent information about what these technologies can actually deliver. We’re looking at performance of the system and its environmental footprint,” explains FPInnovations’ Jim Dangerfield.

“I fundamentally believe, with many of these [biomass] systems, we have to keep in mind the environmental footprint.

“For example, ethanol from grain, from a carbon footprint point of view, is a pretty marginal advance. Being a sustainable industry, our industry needs to be sensitive to its environmental footprint.”

Having the courage to be an early adopter of a technology that dramatically reduces greenhouse gas emissions shows that Kruger Products, at least, is being sensitive to its environmental footprint. Even better, thanks to government incentives pushing companies in the right direction, Kruger will reap bottom-line benefits for its environmental choice as well.

PPC 12

PULP & PAPER CANADA May/June 2010

pulpandpapercanada.com

BIOREFINERY

Drivers and Barriers for Implementation of the Biorefinery An expert panel concludes that the appeal of biorefining is its potential for short- and long-term financial gain, while uncertainty about the technology is its largest drawback.

By Matty Janssen & Paul Stuart, NSERC Environmental Design Engineering Chair in Process Integration

Value

Definition

Explanation

1

Equally important

Drivers/barriers are judged equally important

3

Moderately more important

One driver/barrier is judged moderately more important

5

Strongly more important

One driver/barrier is judged strongly more important

7

Very strongly more important

One driver/barrier is judged very strongly more important

9

Extremely more important

One driver/barrier is judged extremely more important

2, 4, 6, 8

Intermediate judgment values

When a compromise is necessary to give an intermediary judgment between the previous values

pulpandpapercanada.com

Methodology

The methodology applied in this study is based on the principles of multi-criteria decision making or MCDM (Figure 1).

MCDM methodology includes pre-panel and panel phases.

Initially, a panel was struck involving four forest industry memBiorefinery process/product strategies

Pre-panel

Table 1: Pair-wise comparison values used in Analytic Hierarchy Process (AHP)

tion of an improved business model. The biorefinery strategy of a company might consist of any number of a broad range of combinations of biomass feedstocks, processes, and products to be sent to market (Chambost et al, 2007). With the manufacture of new “green” products there is the opportunity for revenue diversification from the existing product portfolio, and if implemented well, better profit margins for forestry companies.

For each biorefinery strategy the unique technology, economic, commercial and environmental risks must be identified and mitigated for successful implementation of the forest biorefinery.

Why is implementation of the biorefinery not progressing more quickly? What are the drivers and barriers for forestry companies? In this paper, a set of such drivers and barriers is defined and their relative importance is evaluated according to the opinions of a panel of industry experts using a multi-criteria decision making (MCDM) method.

Objective of the decision to make

Performance of strategies

Establish biorefinery drivers, barriers and decision structure Introduce decision problem and weighting procedure to panel

Discussion of drivers and barriers

Panel

T

he forestry industry’s current stalemate economic situation has led many companies to seek longer-term strategies that would transform their business models and improve their financial performance. One potential strategy is the implementation of the biorefinery, in one of many possible configurations for revenue diversification to new products, however each of which implies unique technology, market and environmental risks. This paper identifies a set of high-level drivers and barriers related to the implementation of the forest biorefinery, whose goal is to understand better why companies are considering biorefinery implementation, and at the same time, what is slowing implementation of this strategy. With the help of an expert industry panel, the drivers and barriers were ranked. The results showed that overall the biggest driver among those considered was that “the biorefinery potentially offers an opportunity to overcome highly variable and insufficient margins, thus ensuring short-term profitability currently associated with forestry products”, and the biggest barrier was that “the industry’s risk-averse culture and marginal financial performance favours short-term decision making, which may not result in an emphasis on the identification of a longer-term product/market biorefinery strategy.”

The forest biorefinery (FBR) has been defined as the “full integration of the incoming biomass and other raw materials, including energy, for simultaneous production of fibres for paper products, chemicals and energy” (Axegård, 2005). Perhaps a more practical definition for forest industry companies based on business objectives is to maximize the value from forest biomass in order to transform the forest industry through implementa-

Elicitation of decision maker preferences Pair-wise comparison

Trade-off method

Decision weights

Figure 1: Summary of panel-based multi-criteria decision-making (MCDM) methodology May/June 2010 PULP & PAPER CANADA

13

BIOREFINERY Table 2: Definition and elaboration of biorefinery drivers Driver

Elaboration

Panel Discussion

I

The biorefinery potentially offers an opportunity to overcome highly variable and insufficient margins, thus ensuring short-term profitability currently associated with forestry products.

This driver is related to short-term free cash flow, essential for forestry companies to pay debt, dividends and to make capital investments. By implementing a biorefinery strategy leading to improved margins, the financial risk of such a strategy is mitigated and the strategy will be more feasible. Furthermore, other strategies such as partnering with other companies can be instruments for success.

Currently, having good assets that produce commodity products efficiently does not guarantee financial viability of forestry companies. Rationalization of production capacity is thus necessary in order to survive in the short term (”last man standing” strategy). Other revenues are needed to ensure the competitive position of the forestry industry, and commodity products may not be the best strategy for such a diversification.

Therefore, value-added products should be preferred for the longer-term implementation of the biorefinery.

II

Future access to raw materials at competitive prices for the core forestry business may be better secured through biorefinery implementation.

Based on the experience in Europe where there is more advanced energy policy and carbon trading, large increases in the prices of white wood and forest residuals can be expected in the coming years in Canada. At the same time, several provinces are examining land tenure policy which may make access to forest biomass increasingly competitive in the future. By implementing the biorefinery and re-assessing forest harvesting techniques there may be significant potential to a) reduce overall biomass cost in the short term, and b) create the potential for paying more for biomass when this becomes necessary in the longer term.

As demand for biomass increases due to biorefinery implementation, it is expected that prices will also increase.

The competition for biomass leads to the search for other types of biomass. The biorefinery can also use agricultural biomass, energy crops and municipal solid waste (MSW). The location of a facility may in this case be a significant advantage.

The pulp and paper industry’s advantages regarding access to biomass are: 1) certified forest management techniques are used to a great extent, and 2) pulp and paper mills already have access and know-how for forest resources.

III

There is an opportunity resulting from emerging government policy related to climate change, land use, taxation and other issues which can result in financial support for biorefinery implementation.

Implementation of a biorefinery strategy implies significant market and technology risk. It is critical that government mitigates significant biorefinery technology risk by policies and programs that mitigate capital cost and its associated risk. At the same time, carbon trading systems and other policy tools may render green products to be more cost competitive by moderating the higher operating costs expected to be associated with earlygeneration biorefinery technologies.

The biorefinery business model should be viable without operating cost policy-related considerations, which may change in the long-term. However, the mitigation of investment risk during the years of operation provides an important incentive for companies to embark on the biorefinery. Nevertheless, government policy should be consistent over the long term and should not change from government to government. The public image of the pulp and paper industry can improve thanks to government policy. Having a green image will be beneficial to the industry and may indeed assist with government funding.

IV

The biorefinery provides the potential for transforming the business model of a forestry company and increasing its market value.

This driver is related to long-term valuation of the company as this is related to strategic planning. If the biorefinery is implemented successfully, the stock market will recognize this valuation thus providing the forestry company a stronger competitive position over the long term.

This strategic driver is pertinent at the corporate level and is less likely to be a mill-level driver. Nevertheless, value creation is essential for the survival of a company. The sustainability of the production facilities should increase with biorefinery implementation. While improving operating margins, as well, biorefinery facilities should be environmentally benign and have a positive impact on the social fabric in the surrounding areas.

bers involved in biorefinery implementation at their company, a government scientist expert in the area, and a biorefinery design specialist.

During the pre-panel phase, the objective, the drivers and barriers, and the decision structure were defined, and the decision problem and weighting procedure introduced to the panel.

A short list of four drivers and four barriers (Tables 2 and 3) was presented to the panel; these had been established from a long list of criteria related to biorefinery implementation. The long list of criteria was the result of analyses by the NSERC Design Chair at École Polytechnique, based on our experience in biorefinery design. A short list of the most important four drivers and four barriers was identified in order that the MCDM process would be manageable without compromising the essential issues contained in the long list. For instance, the capital cost of implementing a biorefinery technology is a key issue for the forestry industry. This issue is not explicitly mentioned in one of the driver or barrier definitions, however it is implicit in several of the drivers and barriers (see Tables 2 and 3 under Elaboration).

The short list of barriers and drivers was then compared against similar selections made in the literature sources.

The first step of an MCDM panel phase involves the discus14

PULP & PAPER CANADA May/June 2010

sion of the drivers and barriers by the panel. This discussion is critical in order to raise the awareness of the decision maker(s) about the criteria complexity and implications, and as a consequence the panel is better equipped to address decision uncertainty by understanding the different panel member perspectives. Following the panel discussion, the Analytic Hierarchy Process or AHP was applied (Saaty, 1980). AHP is particularly useful when qualitative criteria are compared, which was the case for the drivers and barriers. AHP uses pair-wise comparisons to determine the importance of each driver and barrier. The pairwise comparisons are done using a number scheme from 1 to 9 and their reciprocals (Table 1), and the results are put in a pairwise comparison matrix for the calculation of the weights and to calculate the consistency ratio. When the consistency ratio is smaller than 0.1, the values of the resulting weights are considered trustworthy. Furthermore, the consensus among the panel members for each driver and barrier weight was determined and the results shown graphically by constructing boxplots of the weights of each individual panel member.

Using an MCDM method for evaluating the biorefinery drivers and barriers can guide decision makers in making a balanced decision based on multiple and distinct decision criteria. pulpandpapercanada.com

BIOREFINERY Results and Discussion

The definition and elaboration of the drivers and barriers and a summary of key points from the panel discussion is summarized in Tables 2 and 3. Initial discussion held with panel members indicated that all of these barriers and drivers were considered critical, and thus, the MCDM panel served to distinguish the relative importance of important factors.

A comparison of the short list of drivers and barriers was made with the results from a study on the identification of industry- and company-level factors that are most likely to influence the Finnish bioenergy sector (Pätäri, 2010), as well as a study on the viewpoints regarding where the pulp and paper industry is moving in the bioenergy arena (Patrick, 2010). The comparison of Pätäri’s results showed good agreement with the short list of drivers and barriers. However, Pätäri’s study focused on the Finnish bioenergy sector context and it was necessary to align the drivers and barriers with the North-American context. Patrick identified impediments for progress in biorefinery implementation, which were largely related to the forestry industry’s financial situation.

Drivers

Calculation of the driver weights revealed that the drivers directly related to the economic health of the company are the most important (Drivers I and IV, Figure 2). It was not surprising that the short-term economic Driver I was considered more important than the long-term economic Driver IV, which reflects that the panel members understood the importance of company

transformation over the long term due to implementation of the biorefinery, however that this was less important in decision making than short-term financial metrics. One interpretation of this result is that the industry panel members may require that high returns are needed for biorefinery projects. However, they may be less likely to implement fast payback return projects such as pellet mills in favour of viable strategies that are less profitable in the short term but would lead to added-value products that are more sustainable in the longer term.

Issues related to the procurement of raw materials (ability to pay for biomass feedstock and better guaranteed feedstock for traditional forestry products) were regarded as the next most important issue. Of particular importance to the panel members was the forest industry’s competitive advantage by having an infrastructure already in place for the supply of biomass. Interestingly, the policy-related driver was least important according to the panel members. Although policy drives markets, especially in the case of renewable biofuels, it was clear that the panel industry members preferred not to rely on government policy for the economic viability of their biorefinery strategy except for the shorter term where it was felt that capital cost assistance was essential to mitigate technology risk.

The consistency ratio of the pair-wise comparisons was below 0.10 and therefore the weighting results can be considered trustworthy overall. However, the consensus among the panel members for each of the driver weights varied. Larger boxes in Figures 2 and 3 indicate a lower consensus between the panel

Individual driver weights

0.7 Interquartile range Average of individual weights

0.6 0.5 0.4 0.3 0.2 0.1 0

Driver I

Driver II

Driver III

Driver IV

Figure 2: Average values and consensus among industry panel members for driver weights The average of the individual weights (indicated by the cross) are calculated using the panel members’ set of weights (which were calculated using each individual member’s pair-wise comparisons) Driver I : The biorefinery potentially offers an opportunity to overcome highly variable and insufficient margins, thus ensuring shortterm profitability currently associated with forestry products Driver II : Future access to raw materials at competitive prices for the core forestry business may be better secured through biorefinery implementation Driver III : There is an opportunity resulting from emerging government policy related to climate change, land use, taxation and other issues for financial support for biorefinery implementation Driver IV : The biorefinery provides the potential for transforming the business model of a forestry company and increasing its market value pulpandpapercanada.com

May/June 2010 PULP & PAPER CANADA

15

BIOREFINERY Table 3: Definition and elaboration of biorefinery barriers Barrier

Elaboration

Panel Discussion

I

Government policy that may affect biorefinery implementation strategies remains uncertain in North America.

Government policy related to the content of renewable fuels in gasoline has driven the development of 2nd generation ethanol production processes in North America. However, what about policy that may drive the implementation of processes that lead to added-value green products and the potential for an improved business model for forestry companies? This question is critical and still needs to be addressed by North-American governments at the federal, provincial and state levels.

The panel members felt no need to discuss this barrier after having discussed in-depth about Driver III (Table 2).

II

Early implementers may incur higher technology risk by implementing inefficient earlygeneration technologies and be unaware of emerging or not yet identified biorefinery technologies that may be more cost effective.

To our knowledge there still is no implementation of commercialscale 2nd generation biorefinery technologies at this time, even for the case of bio-ethanol (considered to be about 40 MMgal/ year at the present, and undoubtedly larger capacity in the future).

Scale-up and various other technology risks are significant until commercial scale technologies have been implemented, and even then subsequent generations of these processes will benefit from significant capital and operating cost efficiencies as they further mature and are optimized. As a separate issue, the continuous stream of announcements and press releases about new biorefinery technologies make companies wary that new more cost-effective technologies have yet to be identified which may render strategies established today to be ineffective.

The current forestry industry culture and a resistance to change are the real barriers. On the other hand, distinct to usual investment practice, certain companies consider it to be a competitive advantage for being on the cutting edge of biorefinery development. The choice of implementing an early-generation technology is closely linked with product selection. This creates opportunities, but may be risky because the appropriate business models have yet to be defined.

III

Identification of a quality (nonforestry sector) partner and collaborative structure (joint venture or otherwise) will be critical for success in most cases, and is difficult to establish at this early stage.

There are many appropriate biorefinery process/product strategies for every forestry company depending on such factors as their existing supply chain, product portfolio and geographical location.

However, it is likely the case that there is only a small number of quality partners for success in transforming the business model of forestry companies. How do forestry companies secure these partners? What kind of agreements can be put in place that are acceptable to the partners, and at the same time are flexible for changing technology and market conditions in the future?

Partnering is a critical biorefinery strategy needed for sharing technology, commercial and financial risk, especially in the case of non-commodity products.

Partnerships are a critical component of forestry companies’ biorefinery strategy. However it may be difficult for them to identify the right partner because partnerships are not part of their culture.

IV

The industry’s risk-averse culture and marginal financial performance favours short-term decision making, which may not result in an emphasis on the identification of a longer-term product/market biorefinery strategy.

Unlike the case of capital spending in relatively low-risk technology associated with the core forestry business areas, for successful investment in the biorefinery, a longer-term strategy is essential that will result in transformation of the business model in such a manner that risk is mitigated over the course of several years of implementation. Without this strategy in place, forestry companies will naturally embark on immediate payback projects which are at risk of being unsustainable over the long or even intermediate term.

The forest industry has historically not generated adequate returns from capital spending. As a result, the forestry industry mindset today requires that shortterm value is essential for capital spending. However, strategic long-term investments are likely needed for successful biorefinery strategies if the company vision is to transform. Furthermore, a product-centric development culture needs to be adopted in order to sustain value from implementing the biorefinery.

members. The boxes show the interquartile range which is the difference between the first and third quartiles of the individual panel member’s weights. There was a low consensus among the panellists for Drivers I and IV, the economics-related drivers.

In the case of Driver I there was a tendency to assign a higher weight, but two panel members assigned lower weights to this driver. In the case of Driver IV there is a tendency to assign a lower weight, but the same two panel members assigned a higher weight to this driver compared to the other panel members. Because the consistency of the panel members’ pair-wise comparisons is high, the differences in opinion concerning these two economic drivers are significant. Regardless, Drivers I and IV took up between 69% and 87% of the total weight based on the range of individual weighting results. Interestingly the consensus concerning the low weight for the policy-related driver (Driver III) was found to be high.

Barriers

Consistent with the drivers analysis, the forestry industry’s risk-averse investment culture was found to be the main barrier for implementation of the biorefinery (Figure 3). The barriers 16

PULP & PAPER CANADA May/June 2010

related to technology uncertainty and risk as well as securing “quality” biorefinery partnerships (Barriers II and III, respectively) had similar importance according to the panel members.

Lastly, the policy-related barrier (Barrier I) was judged the least important. Its weight is significantly higher however than the weight for the policy-related driver. Although the industry wants to minimize its reliance on government policy, these policies need to be clearly defined to assist the forest industry set a clear path forward for the biorefinery.

The consistency ratio of the average pair-wise comparisons for determining the barriers was higher than 0.10 and therefore the weighting results need to be considered with more caution than the case for the drivers. One reason for this may be that the barriers were found to be more difficult to interpret for each panel member individually. The consensus among the panel members for each barrier weight was similar (except for the policy-related barrier) and was generally higher than for the driver weights (i.e. the boxes in the barrier box plot were generally smaller) (Figure 3). However, Barriers I and III (policyrelated and partnership-related driver, respectively) each had one outlier, i.e. one panel member who weighed the barriers pulpandpapercanada.com

BIOREFINERY significantly differently than the other panel members.

Conclusions

A group of experts was asked to weigh a set of drivers and barriers related to the implementation of the forest biorefinery via an MCDM panel using the Analytic Hierarchy Process. The weighting results for the drivers showed a more profound difference of opinion between the panel members about the relative importance of the drivers most related to the short-term survival of the forestry industry versus the longer-term. However, the survival of the industry was still the biggest driver according to all panel members. The weighting results for the barriers should be considered with caution because of the low consistency of the pair-wise comparisons of the barriers. Nevertheless, the biggest barrier to biorefinery implementation was risk (technology, financial, market, policy) and the forestry industry’s risk-averse culture.

Acknowledgments

The authors would like to thank the panel members for their participation in this study. This work was supported by the Natural Sciences Engineering Research Council of Canada (NSERC) Environmental Design Engineering Chair at École Polytechnique in Montréal.

References

Axegård, P. (2005). The future pulp mill – A biorefinery.

In First International Biorefinery Workshop. 1st International Biorefinery Workshop, Washington DC Chambost, V., Eamer, B., and Stuart, P.R. (2007). Forest Biorefinery: Getting on with the job. Pulp and Paper Canada, 108(2), 19-22.

Pätäri, S. (2010). Industry- and company-level factors influencing the development of the forest energy business – insights from a Delphi Study. Technological Forecasting and Social Change, 77(1), 94–109.

Patrick, K. (2010). Survey finds optimism and skepticism about future of integrated biorefineries. Online: http://www. tappi.org/content/enewsletters/ahead/2010/issues/2010-01-20. html.

Saaty, T. L. (1980). The analytic hierarchy process. New York, NY, USA: McGraw-Hill.

Matty Janssen and Paul Stuart are affiliated with the NSERC Environmental Design Engineering Chair in Process Integration, Department of Chemical Engineering, École Polytechnique Montréal, Montréal.

PPC

Individual barrier weights

0.7 Interquartile range Extreme utlier Outlier Average of individual weights

0.6 0.5 0.4 0.3 0.2 0.1 0

Barrier I

Barrier II

Barrier III

Barrier IV

Figure 3: Average values and consensus among industry panel members for barrier weights The average of the individual weights (indicated by the cross) are calculated using the panel members’ set of weights (which were calculated using each individual member’s pair-wise comparisons) Barrier I : Government policy that may affect biorefinery implementation strategies remains uncertain in North America Barrier II : Early implementers may incur higher technology risk by implementing inefficient early-generation technologies and be unaware of emerging or not yet identified biorefinery technologies that may be more cost effective Barrier III : Identification of a quality partner (non-forestry) and collaborative structure (joint venture or otherwise) will be critical for success in most cases, and is difficult to establish at this early stage Barrier IV : The industry’s risk-averse culture and marginal financial performance favours short-term decision making, which may not result in an emphasis on the identification of a longer-term product/ market biorefinery strategy pulpandpapercanada.com

May/June 2010 PULP & PAPER CANADA

17

PAPTAC abstracts (Full peer-reviewed manuscripts available at www.paptac.ca)

Development of a FlowFollowing Sensor Package for Application in Chemical Pulp Digesters

By T.C.M. Graham, A.R. Mohammadi, N. Sadeghi, E. Albadvi, S. Mirabbasi, M. Chiao, J. Madden, and C.P.J. Bennington

Élaboration d’une méthode de débit continu pour application dans les lessiveurs de pâte chimique

Abstract: A prototype flow-following sensor platform has been developed for use in multi-phase chemical reactors targeted for operation inside a kraft pulp digester (pH~13, 175C and 2.0 MPa).

The device is assembled using high temperature microelectronic components and micro-electro-mechanical sensors (MEMS) to achieve a small size and an overall density similar to that of a wood chip. An IC-SmartChip, approximately the size of a typical wood chip, is under development. However, the device used to collect the data presented is a prototype SmartChip, approximately the size of a bar of soap. The SmartChip sensors include a resistance temperature device (RTD) and a precision clock, which allows calculation of a location specific H-factor for a cook. A static pressure sensor can also be included on the prototype, which will allow the vertical position of the SmartChip to be tracked, provided the SmartChip moves during the cook, such as in continuous operations. Multiple SmartChips deployed in a single cook can be used to measure the variability of the treatment achieved during the process. The sensors and electronics have been successfully tested up to 180C and 1.3 MPa for several hours in a 5L laboratory batch digester. The accuracy of SmartChip sensors whas shown to be better than +/-0.55C, +/-2 kPa and 2 minutes in 8 hours.

Paper presented at the 96th PAPTAC Annual Meeting 2010 in Montreal, Que., February 2-3, 2010.

Keywords: MULTIPHASE CHEMICAL REACTORS; PULP DIGESTERS; KRAFT PULP MANUFACTURE; WOOD CHIPS; MICRO-SENSORS; MEMS SENSORS, REMOTE MEASUREMENT; FLOW-FOLLOWING Full manuscript available at www.paptac.ca.

The Efficiency of Softwood Kraft Pulps in Improving Paper Machine Runnability

By X. Hua, I. Pikulik, and N. Gurnagul

Effets des pâtes kraft de résineux sur l’amélioration de l’aptitude au passage sur machine

Abstract: A method for assessment of the reinforcing properties softwood kraft pulps used to improve fine paper machine runnability was developed. The assessment is based on wet-web tensile strength,

18

Pulp & Paper Canada May/June 2010

Precoat and Topcoat Effect on the Final Printability – Part 1: Using Mercury Intrusion to Analyse the Coating Structure

By D. Matte, A. Dimmick, P. Mangin, C. Daneault

Effet des couches de préparation et de finition sur l’imprimabilité finale – Partie 1 : Utilisation de la porosimétrie au mercure pour l’analyse de la structure du couchage

Abstact: Mercury intrusion testing is a well established tool, and has been used extensively within the industry to give a great deal of information to the papermaker about the paper and coating structure. The test has been invaluable in predicting or troubleshooting many areas such as blister resistance and printing issues. However, results can vary widely depending on the choice of materials (pigments or binder) used in different formulations. The main goal of this paper is to explain how to achieve a good analysis of mercury intrusion by good manipulations of the data for double coated paper.

It is important to define the point in the data collected where the pore diameter is representative of the area located around the low and high mercury pressure and thus eliminate the occlusion and/ or defects effects. An explanation of the way to identify the point of separation between the coating layers and the base paper and between the pre-coat and top coat together is also provided. The hexadecane method and the correction (performed with blank correction option) in the Autopore™ program from Micromeritics can be used to achieve these results. An example of the correction for mercury intrusion method used is also shown using data from a study done for a doctorate begin at University of Québec à Trois-Rivières.

Paper presented at the 95th PAPTAC Annual Meeting 2009 in Montreal, Que., February 3-4, 2009.

Keywords: MERCURY INTRUSION, WASHBURN EQUATION, HEXADECANE, PORE, PORE STRUCTURE, CONTACT ANGLE, SURFACE ENERGY, INTERFACIAL TENSION, BLANK CORRECTION, DOUBLE COATED PAPER, PRE-COATED PAPER, FREE SHEET Full manuscript available at www.paptac.ca. stretch, tensile energy absorption, and failure envelopes of handsheets, made from the softwood pulp alone and its blend with hardwood, combined with the evaluation of water removal characteristics of pulps. Considerable differences were found in the reinforcement potential of the three pulps. Conventional measurement of “pulp strength” or refining curve did not reveal its reinforcing properties.

Paper presented at the 95th PAPTAC Annual Meeting 2009 in Montreal, Que., February 3-4, 2009.

Keywords: FIBRE LENGTH, HARDWOOD, KRAFT PULP, PAPER MACHINES, EFFICIENCY, RUNNABILITY, PULP PROPERTIES, QUALITY, REFINING, ENERGY, REINFORCEMENT, SOFTWOOD, STRETCH, TENSILE STRENHGTH, RUPTURE WORK, WATER RETENTION, WATER REMOVAL, WET BREAKS, WET WEBS Full manuscript available at www.paptac.ca. pulpandpapercanada.com

BIOREFINERY

Simulation of a Kraft Pulp Mill for the Integration of Biorefinery Technologies and Energy Analysis

By E. Mateos-Espejel, M. Marinova, S. Schneider, J. Paris

Abstract: A methodology for the construction of computer simulations of chemical pulp mills suitable for conversion into integrated biorefineries has been proposed. A simulation of a dissolving pulp mill located in Eastern Canada has been developed using this methodology. The objective of the simulation is to supply data for energy and water studies and to analyze the implementation of biorefining technologies. The methodology covers all stages of the simulation development, from the data collection to the converged solution. The characteristics of the simulation are described as well as examples that illustrate its features.

T

he Canadian pulp and paper industry is going through a precarious period due to the appearance of new competitors from emerging countries, the reduction of the demand of paper-type commodity products, and the increase of energy prices. The conversion of existing chemical pulp mills into forest biorefineries could be part of the solution to improve the competitiveness of the industry. However, to increase the profitability of the pulp millbased biorefineries and reduce their dependency on fossil fuel, the water and steam consumption should be optimized.

The first step of any retrofit or energy study is the construction of a computer simulation that accurately represents the process configuration and the operating conditions of the mill.

Computer simulations are typically used as a source of data for troubleshooting problems, for the comparison to typical practices, and to validate possible improvement scenarios [1].

They should be constructed with a specific purpose and the appropriate level of detail [2,3].

For example, an online dynamic simulation developed for training process operators should consider more process parameters than if it is required for optimizing the equipment design [4,5].

A real process is never in a true and rigorous steady state; local adjustments of operating conditions, equipment turnover, feed rate variations, etc., cause constant fluctuations which affect steam and water consumption. Moreover, measured parameter values contain noises or errors (random or gross) caused by imperfections of sensors and recording equipment. The simulation of a real process should represent a long pulpandpapercanada.com

term average steady state.

A methodology for the construction of computer simulations of chemical pulp mills suitable for conversion into integrated biorefineries has been proposed and applied to develop a simulation of a dissolving pulp mill located in Eastern Canada. CADSIM Plus® (Aurel Systems Inc.) process simulation software for the pulp and paper industry has been used for this purpose.

E. MATEOS-ESPEJEL École Polytechnique de Montréal, Dept. of Chemical Engineering, Montreal

CONTEXT

The simulation, developed using the proposed methodology, is an important step in the definition and characterization of each industrial process. Consequently, it can be used for: • Energy systems analysis and pre-benchmarking of the process; • Systems interactions analysis and development of energy enhancement options; • Formulation of an implementation strategy; • Post-benchmarking and results evaluation.

A methodology that considers these energetic aspects has been developed at École Polytechnique [6]; it can be applied to pulp and paper processes, as well as to integrated biorefineries.

METHODOLOGY

The definition of the base-case process is a critical step, since the reliability of the analysis undertaken later and, ultimately the value of the results produced, depend largely of the level of confidence that can be attributed to the data gathered by simulation. The goal of this step is to construct a process simulation which is a reliable representation of a long term average steady state of the base-case process apprehended by data collected in the mill or estimated from other sources. It must be focused on its

M. MARINOVA École Polytechnique de Montréal, Dept. of Chemical Engineering, Montreal

S. SCHNEIDER École Polytechnique de Montréal, Dept. of Chemical Engineering, Montreal

J. PARIS École Polytechnique de Montréal, Dept. of Chemical Engineering, Montreal

May/June 2010 PULP & PAPER CANADA

19

T37

T38

BIOREFINERY intended utilization which is, for the case presented, the energy performance and the integration of biorefining technologies. In this case, steam and water systems must be modelled accurately and in detail. On the other hand, simplifications should be introduced whenever possible, to avoid unnecessary details that would burden the simulation development task, increase the risk of computational problems, and hinder its utilization. A seven step systematic procedure has been formulated and applied to the development of a base-case simulation.

1. Collection of primary mill data The reliability of the simulation depends on the information used for its development. Several sources must be consulted.

In order to represent the main process variations, it is suitable that the data collected cover a range of operating conditions (e.g. winter and summer). The objective is to have a sufficient amount of data to establish the configuration, and the energy, water and chemical balances of the complete process and its individual sections. The data collected consist of updated P&IDs (Process & Instrumentation Diagrams) and other existing flow sheets indicating process modifications, archived data, snapshots from the centralized control and data acquisition systems, laboratory records and, when available, results from previous audits or engineering studies.

2. Data pre-treatment The primary mill data are sorted by seasons, averaged, evaluated by simple statistical tests (such as standard deviation), outliers, transitional periods, and non-representative operating conditions are removed. These data are designated as treated mill data.

3. Construction of the simulation diagram This is done in a stepwise piecemeal fashion, systematically covering each mill process area one at a time, utilising P&IDs and other process diagrams.

The various types of paths such as pulp, water, steam and process liquors are traced first; this can be done by means of AutoCAD® (Autodesk) or similar software. The level of detail of the process sections might vary depending on 20

PULP & PAPER CANADA May/June 2010

the objective of the simulation. However, it should be taken into account that an extremely detailed diagram would require more iterations to converge and more data to support its development.

Simplifications can be introduced in the diagram but without modifying the whole or sectorial configurations of the process.

4. Supplying input parameter values to the simulation A large amount of parameter values must be supplied to the simulation software to perform all computations (primarily heat and mass balances) involved in the simulation model. Whenever possible, values of treated mill data should be used. In general, this source is very insufficient and additional input parameter values must be estimated by other means: prior experience, partial heat or mass balances, literature or, software default values when available. Some input parameter values must be adjusted to obtain computational convergence; this is done by trial-and-error and greatly facilitated if the simulation diagram is kept in the open loop mode, i.e by tearing open sensitive recirculation loops without exact matching of the open ends.

The process streams of pulp and paper processes contain several components; the choice of the components to be taken into account will depend on the objective of the simulation. Simulations that will be used for energy studies could include components such as fibres, water, and total dissolved solids [6]. Water closure or biorefinery studies require a more detailed set of components in order to monitor the distribution of elements, properties such as pH or COD, as well as wood components.

5. Assembling the simulation sections The simulations of the various sections are then connected and the internal and external recirculation loops are closed.

This procedure is done one step at a time, and in an orderly fashion verifying that computational convergence is maintained at each step. At this point a complete functional simulation of the base-case process has been generated; however, as sections were linked and loops closed, many parameter values have been modified to various degrees

to obtain computational convergence, i.e., to satisfy the systems of equations constituting the simulation model. In the last step of the procedure, a systematic, computerized adjustment can be performed to improve the concordance between simulation and actual process at steady state.

6. Creating and managing data files In the course of the development of the simulation various types of data are assembled, modified, and supplied to the software as input parameters.

Other data produced by the simulation (output parameters) will be used to compute derived parameters (efficiency rates, performance indicators…) and for analysis purposes. In subsequent steps of the methodology the process configuration and operating conditions will be changed. It is convenient to create an Excel® (Microsoft) worksheet to manage, organize and record modifications of those data. Two-way links are established from the Excel file to the simulation software (downstream links) and to other computational (MATLAB®, MathWorks) and treatment (Word®, Microsoft) software (upstream links).

7. Validation and final simulation parameters adjustment The results of the simulation are validated in two steps. First a direct comparison between original simulation values of selected key parameters will help detect gross errors at the data collection and pre-treatment stages or unaccounted streams in the simulation diagram. Those discrepancies can generally be corrected by consultation and verification with mill staff. A second step can be a systematic computerized adjustment of simulation parameters.

It consists primarily of a minimization of the weighted sum of squared differences between the treated mill data and the corresponding simulation values. A method called data reconciliation, which is well documented in the scientific literature [7,8], is often recommended to perform a global process adjustment.

However, it requires a large amount of excess data, the redundancy, to solve the complete set of modeling equations, an instance which is rarely encountered in actual problems where scarcity of data pulpandpapercanada.com

PEER REVIEWED (negative redundancy) is generally the case [9]. The results obtained from the simulation are reconciled, as all mass and energy balances are correct. Therefore, the verification with mill staff of the values of the simulation is generally sufficient to establish its reliability.

• Chromatographic and crystallization steps for the purification of xylose and xylitol, • A fermentation stage for the production of ethanol, • An anaerobic treatment to produce biogas.

CASE STUDY

Simulation development The simulation of an operating dissolving pulp mill with a production of 400 adt/d has been developed. The objective of the simulation is to supply data for the energy and water analysis of the process as well as to analyze the integration of hemicelullose biorefining technologies.

Since the simulation described here was developed on CADSIM Plus® some comments are linked to characteristics of the software and may not apply to other simulators. The design and data structure of CADSIM Plus® modules is inspired by equipment actually in use by pulp and paper mills, which facilitates the understanding and the use of the simulation by mill staff. This software has several advantages which are presented below.

Dissolving pulp production The conversion of a conventional chemical pulp mill, with kraft or sulphite pulping process, into a dissolving pulp mill is an opportunity to establish a hemicellulose-based biorefinery. Dissolving pulp is a low-yield chemical pulp with high cellulose content suitable for making rayon, cellulose acetate, and cellophane [10]. A simplified representation of a kraft process with a pre-hydrolysis stage is given in Fig. 1.

The hemicellulose is solubilized by exposing wood chips to hydrolysis prior to pulping. The produced pre-hydrolysate contains sugars such as monosaccharides (arabinose, xylose, mannose galactose, glucose) and oligosaccharides (galactoglucomannan, and glucuronoxylan), and other chemical compounds (acetic acid, furfural, phenolic compounds). The hydrolysate can be used as a feedstock for: • A further acid treatment to produce furfural,

nent concentrations of the major process streams were also obtained. The flow diagram developed contains the detailed information on production, distribution, utilization and post-utilization treatment of water and steam. Departments that directly affect steam and water consumption, such as pulping, bleaching, drying, black liquor concentration, and steam production, have been modeled in detail. Simplified models were used for the recaustification section and lime kiln which are not large consumers of steam.

Direct steam injections and mixing of streams at different temperature in tanks or process lines have been highlighted.

Components definition Some of the components involved in pulp and paper processes (i.e. electrolytes and fibres) can be difficult to simulate in software where strict thermodynamic models are used to compute the components’ properties and unit operations.

Such situations will require efforts to define the thermodynamic properties of the components and to adjust the existent unit operation modules to the pulp

Simulation diagram The P&IDs of the various process sections and the steam and water consumption for the winter and summer of 2009 were available. The compo-

Fig. 2. Process streams in a typical evaporation section.

BL= black liquor; P = pressure; DS= dissolved solids; T= temperature; m = mass flow

Fig. 1. Simplified schema of a dissolving pulp mill.

WL= while liquor; BL= black liquor; Conc. = concentration of BL; RB = recovery boilers; Recaust. = recaustification pulpandpapercanada.com

Fig. 3. Example of simulation assembling May/June 2010 PULP & PAPER CANADA

21

T39

T40

BIOREFINERY and paper process operations [11]. The utilization of CADSIM Plus® as a simulation software eliminates this inconvenience. In addition, process parameters, such as sulfidity, alkalinity, etc., can also be computed.

A detailed set of components has been specified in the simulation; they are: water, steam, wood constituents, inorganic compounds, and hemicellulose-derived sugars. The graphical methods, typically used [12-14] to analyze the water systems, consider only the presence of one contaminant. Therefore, the total dissolved solids (DS) have been defined to regroup all contaminants in the process streams. However, the detailed definition of contaminants can also be used to track the accumulation of unwanted materials (i.e. in the bleaching section).

Input parameters The input parameters in CADSIM Plus® can be supplied in different ways.

This feature can be used to the advantage of the user to validate some of the information obtained from the mill. The main examples are the water and steam flows. Figure 2 shows the example of the evaporators section, where two options are available: to fix the amount of steam required (data from the mill) by the evaporators, and compute the amount of dissolving solids at the output, or to fix the desired concentration of dissolved solids at the output, and compute the amount of steam required. The second option is recommended because of the validation and analysis features. The steam utilization in mills is well monitored because of its high cost [6], therefore it is an appropriate parameter for validation. On the other hand, the identification of gross differences between simulation and actual steam consumption can be indicative of poor insulation or equipment operation. Therefore, the appropriate way of supplying the data to the simulation should complement the data validation and process analysis. The same procedure can be applied to the water consumers.

It is also recommended to specify relationships between parameters, usage ratios, stream splits, percentages or controllers settings, so the simulation can be used to test modifications to the pulp 22

PULP & PAPER CANADA May/June 2010

production. This approach is very useful when new scenarios or configurations have to be introduced in the simulation.

Simulation assembling The simulation contains several global recirculation loops, such as water reutilization, white and green liquor reuse and condensate recovery, in addition to shorter internal loops in each section.

In the initial stage of the simulation all loops are torn open. Once all sections have converged individually the loops are closed one at a time starting from the inner loops (in each section) and finishing with the global recirculation loops. Figure 3 shows an example of this procedure. First, the inner recirculation between washers and screeners or between evaporation effects are established; then, the inter-connections between sections such as washers and bleaching or washers and evaporators; later, the recirculation loops between sections such as effluent reutilization such as between bleaching and washing; and finally the utilities reutilization streams such as condensates recovery.

The objective of this procedure is to create a set of initialization values required for an overall convergence which otherwise will be difficult to achieve. This procedure is fundamental in the case of kraft-based biorefineries, where several interconnections would exist between the current kraft process and the retrofitted biorefinery units.

Data validation The difference between the values computed by the simulation and the treated mill data for the steam production is 0.9%. All individual steam-using operations have differences below 10%. For the water consumption, the difference between the computed water intake and the mill value is 4%, which is lower than the typical values found in the literature [15].

Simulation characteristics The developed simulation contains 19 departments, 498 main direct and controlled settings, and 82 external recirculation loops. The simulation was run on a Intel® Pentium® Dual T400 2.16GHz processor and it required between 45 – 60 min of CPU time to reach the

steady state. A change in the production rate needs the same time to converge completely, but the time required for convergence following the modification in consistency, temperature or flow rate is inferior.

The converged simulation represents a steady state system. This evolution of the simulation of a parameter value change is governed by computing and iterative procedures; it does not represent the process dynamics such as start up or after production rate changes.

CONCLUSIONS

A methodology has been proposed to construct a computer simulation and its application has been illustrated in a dissolving pulp mill. The purpose of the simulation dictates how detailed it should be. However, it must remain as simple as possible. The level of detail directly impacts the amount of data to be gathered, thus affecting the number of iterations and simulation sequence required to converge. The specification of the input parameters to the simulation should aid the validation procedure and analysis of the process. The elements to be considered in the development of a dissolving pulp mill which will be converted into a biorefinery have been presented. In this case, a detailed description of the existing components in the process streams, of the utilities systems, and of the sections affecting the energy efficiency is required. Computer simulations are the foundation to further analysis and testing possible configurations changes. Therefore, the simulations should be systematically defined and characterized to represent the operation of the real process.

ACKNOWLEDGEMENTS

This work was supported by a grant from the R&D Cooperative Program of the National Science and Engineering Research Council of Canada. The industrial partners to this project and, more particularly, the mill which supplied the data, are gratefully acknowledged.

M. Marinova acknowledges the support from NSERC and FPInnovations – Paprican Division for her Industrial R&D Fellowship. This work has been a joint effort to which the following students have contributed: Safa Amara, pulpandpapercanada.com

PEER REVIEWED Adriana Cakembergh, Sebastian Schuster and Stefan Würgler.

LITERATURE

1. LUNDSTRÖM, A., VON SCHENCK, A., AND SAMUELSSON, A. Process Simulation - A Tool for Process Improvements. PulPaper 2007 Conference, Helsinki (2007).

2. SCHNEIDER, D.F., Build a Better Process Model, Chem. Eng. Prog. 94 (4): 75-79 (1998).

3. DAHLQUIST, E., ed. Use of Modeling and Simulation in Pulp and Paper Industry. COST office (2008).

4. BLANCO, A., DAHLQUIST, E., KAPPEN, J., MANNINEN, J., NEGRO, C., AND RITALA, R., Modelling and Simulation in Pulp and Paper Industry.

Current State and Future Perspectives. Cellul. Chem.

Technol. 40 (3-4): 249-258 (2006).

5. TURON, X., LABIDI, J., AND PARIS, J., Simulation and Optimization of a High Grade Coated Paper Mill, J. Cleaner Prod. 13 (15): 1471-1480 (2005).

6. MATEOS-ESPEJEL, E., SAVULESCU, L., AND PARIS, J., Base Case Process Development for Energy Efficiency Improvement, Application to a Kraft Pulping Mill: Part I Definition and Characterization, Chem. Eng. Res. Des. (submitted 2009).

7. JACOB, J. AND PARIS, J., Data Sampling and Reconciliation, Application to Pulp and Paper Mills. Part I:Methodology and Implementation, Appita J. 56 (1): 25-29 & 52 (2003).

8. BROWN, D., MARECHAL, F., HEYEN, G., AND PARIS, J., Data Reconciliation and Sampling Protocol Design, Case of a Paper Deinking Process, Paperi ja Puu.

86 (7): 565-570 (2004).

9. JACOB, J. AND PARIS, J., Data Sampling and Reconciliation, Application to Pulp and Paper Mills. Part II: Case Studies, Appita J. 56 (2): 116-121 (2003).

10. SIXTA, H., HARMS, H., DAPIA, S., PARAJO, J.C., PULS, J., SAAKE, B., FINK, H.-P., AND RÖDER, T., Evaluation of New Organosolv Dissolving Pulps. Part I: Preparation, Analytical Characterization and Viscose Processability, Cellulose. 11: 73-83 (2004).

11. ASSELMAN, T., Fermeture des Circuits D’eau dans les Usines Intégrées de Papier Journal: Problématique et Étude de Cas, École Polytechnique de Montréal, MSc Thesis p. 218 (1995).

12. DHOLE, V.R., Fluid Efficiency, U.P. 5824888.

Linnhoff March limited (1998).

13. WANG, Y.P. AND SMITH, R. Wastewater Minimization, Chem. Eng. Sci. 49 (7): 981-1006 (1994).

14. EL-HALWAGI, M.M., Pollution Prevention Through Process Integration Systematic Design Tools. 1st ed., San Diego, California: Academic Press (1997).

15. SAVULESCU, L.E. AND ALVA-ARGAEZ, A., Direct Heat Transfer Considerations for Improving Energy Efficiency in Pulp and Paper Kraft Mills, Energy.

33: 1562-1571 (2008).

Résumé :

Une méthodologie pour simuler des usines de mise en pâte chimique qui peuvent être converties en bioraffineries intégrées a été proposée. La simulation d’une usine produisant de la pâte dissoute, située dans l’est de Canada, a été développée en utilisant cette méthodologie.

L’objectif de la simulation est de fournir des données requises pour l’étude des systèmes d’eau et d’énergie ainsi que pour l’analyse de l’implantation des technologies de bioraffinage. Les caractéristiques de la simulation et des exemples illustrant son utilisation sont présentés.

Keywords: SIMULATION, BIOREFINERY, KRAFT PROCESS, ENERGY EFFICIENCY Reference: MATEOS-ESPEJEL, E., MARINOVA, M., SCHNEIDER, S., PARIS, J. Simulation

of a Kraft Pulp Mill for the Integration of Biorefinery Technologies and Energy Optimization. Pulp & Paper Canada 111(3): T37-T41 (May/June 2010). Paper presented at the PAPTAC Annnual Meeting in Montreal, Que., February 2-3, 2010. Not to be reproduced without permission of PAPTAC. Manuscript received December 1, 2009. Revised manuscript approved for publication by the Review Panel April 2, 2010.

letters editor TO THE

cindy@pulpandpapercanada.com pulpandpapercanada.com

May/June 2010 PULP & PAPER CANADA

23

T41

T42

ETHANOL

Critical Analysis of Emerging Forest Biorefinery (FBR) Technologies for Ethanol Production

By J. Cohen, M. Janssen, V. Chambost and P. Stuart Abstract: The emergence of biorefineries using second-generation lignocellulosic feedstocks may be promising for some forestry companies for the production of bioethanol, and numerous emerging technologies are being developed to achieve this. The choice of a suitable technology at the early design stage can be a challenging task due to scarce and uncertain information available from technology developers, and the particular context and risks associated with implementing the biorefinery. The objective of this paper is to define and weigh critical metrics for evaluating the potential of nearly-proven and emerging forest biorefinery technologies for bioethanol production. The key technology issues such as process efficiencies and costs, as well as process design-related information such as feedstock flexibility were considered. Not surprisingly the MultiCriteria Decision Making (MCDM) panel results showed that economic and process integration-related criteria were found to be the most important. When the weights were applied to 7 different technology platforms, it was found that both biochemical and thermochemical applications have unique competitive advantages for the short and long terms, however that thermochemical process routes were generally favored for ethanol production by the panelists.

M

ergers/acquisitions and cost reductions have helped the North American forestry industry for shortterm survival in recent years [1]. However, to improve financial return for the longer term, many forestry companies are considering transformation of their business models and revenue diversification through implementation of the biorefinery [2], which involves various risks that must be systematically identified and mitigated.

Biorefinery options can potentially expand the product portfolio of forestry companies by the production of biofuels such as bioethanol, addedvalue chemicals, or new bio-materials [3]. The interest in producing bioethanol from lignocellulosic feedstocks can be related to drivers such as energy security and biofuels legislation, as well as environmental concerns and the “food versus fuel” debate surrounding corn-based ethanol [4, 5].

However, identifying the best biorefinery strategy to produce bioethanol is not obvious given the various alternatives available in terms of lignocellulosic biomass feedstocks and process pathways [6, 7].

According to Badger [5], ethanol can be produced via two main pathways: (1) biochemical pathways using acid and/or enzymes for sugar hydrolysis and fermentation, and (2) thermochemical pathways using gasification to produce syngas followed by a catalytic or biochemical reaction to produce ethanol.

Implementing a biorefinery process and producing ethanol can be achieved via different strategies, for example financing stand-alone greenfield 24

PULP & PAPER CANADA May/June 2010

installations [8], or integrating biorefinery process technology in retrofit to existing pulp and paper mills. Several cost and other advantages are possible from the retrofit context using the existing assets of forestry companies, for example by improving the energy efficiency of the existing mill processes, reducing operating and capital costs of the biorefinery process through integrating with existing mill infrastructure, or by synergies in feedstock supply. In North America, technology providers are active in the rapidly growing biofuels market [9]. With intense research activities benefiting from a range of funding programs, several technologies have now reached the pilot scale [10] and more recently the demonstration scale (Fig. 1). These facilities are producing ethanol at a progressively increasing capacity [11] (Table I), which can be expected to grow dramatically in the coming years. There is significant competition to bring these developing technologies to the market at commercial scale. Being developed mainly by small and medium enterprises (SMEs), there is high uncertainty and scarcity of information related to the bioethanol processes making earlystage technology assessments difficult.

The techno-economic evaluation of ethanol production integrated into pulp and paper mills has been considered in several studies. Wooley et al. [12] completed a prefeasibility study on ethanol production. Van Heiningen [13] as well as Frederick et al. [14] carried out techno-economic analyses of biochemical processes for ethanol production combined with acetic acid production. Larson et al. [15] did a cost-based analysis of gasification technologies for the forest biorefinery.

J. COHEN NSERC Environmental Design Engineering Chair in Process Integration, Department of Chemical Engineering, École Polytechnique – Montréal, Montréal

M. JANSSEN NSERC Environmental Design Engineering Chair in Process Integration, Department of Chemical Engineering, École Polytechnique – Montréal, Montréal

V. CHAMBOST NSERC Environmental Design Engineering Chair in Process Integration, Department of Chemical Engineering, École Polytechnique – Montréal, Montréal

P. STUART NSERC Environmental Design Engineering Chair in Process Integration, Department of Chemical Engineering, École Polytechnique – Montréal, Montréal pulpandpapercanada.com

PEER REVIEWED Table I. Cellulosic ethanol facilities under development Company

Iogen Lignol POET Coskata Enerkem

Main Pathway

Status

Capacity Mgal/yr

Bio Thermo Thermo Thermo Thermo

Pilot Pilot Pilot Pilot Pilot-Demo

0.51 0.25 0.02 0.04 1.32

More recently HytĂśnen and Stuart [16] compared the technoeconomics of both thermochemical and biochemical alternatives for ethanol production integrated into a pulp and paper mill. Nevertheless, no technology screening strategies have been presented in the literature for evaluating the range of biorefinery opportunities prior to detailed engineering analyses.

Investing in the forest biorefinery necessarily implies a systematic analysis of risk by forestry companies [17]. Capital spending decision-making is typically profit-driven, however, the bioethanol evaluation is different due to such issues as intense environmental scrutiny and the emergence of new technologies [18]. Companies have the challenge of evaluating technologies carefully at the early design stage in order to identify those that are the most promising even though still under development, in order to improve the likelihood of (1) the economic viability of implemented projects, and (2) the long-term competitive position of the company in the market when producing biorefinery products.

To this end, evaluation criteria should be established to assess the potential technology alternatives, given the unique characteristics of the challenges associated with biorefinery implementation.

These evaluation criteria should be considered and assembled in a systematic methodology so that company decision-makers can clearly see and understand the basis for comparison.

Fig. 1. Development scale of lignocellulosic ethanol in North America

OBJECTIVES

The objectives of this paper were to carry out a critical analysis of available information in the literature concerning emerging technologies for ethanol production using a set of multi-disciplinary criteria, and to identify among these criteria which ones are the most significant for early-stage design screening, using the perspective of a forestry company.

Fig. 2. Methodology for determining criteria for early design stage biorefinery process screening

METHODOLOGY

A three-step methodology (see Fig. 2) was developed to identify and evaluate key criteria for the selection of a preferred ethanol production technology at the early design stage. The objective of the first step was to identify a preliminary list of key factors for evaluating potential technology pathways to produce ethanol.

In order to identify these preliminary key factors, a systematic technology evaluation was carried out using process design methodology for a hypothetical pulp and paper mill. Factors such as feedstock flexibility, process considerations, and economic variables were listed during the design (Fig. 3). Furthermore, links between these factors were identified. For instance, both feedstock flexibility and product portfolio have an impact on process efficiency, as well as safety and technological risk. Process efficiency also has a direct impact on operating costs. During the second step of this methodology, these preliminary key factors were applied to a group of selected technologies to gather information pulpandpapercanada.com

Fig. 3. Key factors for technology evaluation identified from biorefinery design activities May/June 2010  PULP & PAPER CANADA 

25

T43

T44

ETHANOL for further analysis. These key factors were then refined to establish a set of criteria.

Finally in the last step, all previous criteria were weighted through a Multi-Criteria Decision Making (MCDM) panel leading to the evaluation of technologies and their ranking.

Among the biochemical and thermochemical pathways to produce ethanol, potential technologies were selected according to three requirements that underlined both current and future technical and commercial developments: • Recent scientific publications, webbased information and/or press releases.

• Information on existing pilot plant facility in North America.

Seven biorefinery technologies were considered (Table II). Five of them employed biochemical pathways, and the other two were thermochemical pathways. The last activity of this first step was to select one of these technologies, to gather available information about it and to analyze this information’s reliability and

potential use for parameter evaluation. The result of this analysis was a preliminary list of key factors to consider for process technology evaluation, and a case study collecting the information for one specific technology.

The objective of the second step was to gather information for the remaining six technologies in order to define a list of multi-disciplinary criteria for evaluation.

A set of criteria for further analysis was defined based on the following assumptions: • At the early screening stage for biorefinery process technologies, insufficient information is found to assess safety risk properly.

• Only process steps involved in ethanol production were considered for technology evaluation, and by-products were only considered for economic analysis • Coupled criteria have to be evaluated jointly in order to provide consistency in evaluation.

A systematic approach was used to

Table II. Technologies for ethanol production considered in this study Generic Description of technology

Type Pre-treatment A B C D E F G

Bio Bio Bio Bio Bio Thermo Thermo

Acid Steam explosion Steam explosion Organosolv Hot Water Mechanical Mechanical

Hydrolysis or Thermal treatment

Fermentation or Synthesis

Dilute acid Concentrated acid Enzymatic Enzymatic SSF Dilute acid High-severity gasification Low-severity gasification

Standard Standard Standard Enzymatic SSF Standard Gas phase fermentation Catalytic conversion

Fig. 4. Approach employed for defining process evaluation criteria

26

PULP & PAPER CANADA May/June 2010

ensure a consistent definition of the criteria (see Fig. 4). An “ideal” definition of each criterion was made assuming that unlimited and correct data were available on each technology, and then a second “practical” definition was made based on scarcity and uncertainty of information. Based on literature information, the metrics were calculated and a level of confidence in its results was assessed. For example, profitability metrics were first oriented towards an Internal Rate of Return (IRR) calculation considering interest rates and fluctuations in market prices for bio-products.

Lack of information regarding industrial biorefinery implementations, uncertainty related to market prices and the use of detailed discounted cash flows at this early design stage led us to consider a broader metric based on a payback calculation, called here a standard Return On Investment. A common mathematical formula and calculation assumptions (e.g., fixed market prices, fixed bioethanol production volume, etc.) were used to define the metric and evaluate the profitability of all the technologies. Regarding this criterion, only publically available information were used leading to large uncertainties in results and a lower confidence.

Each technology was designed for the same scale of producing 20 million gallons of ethanol per year. This represents a large scale-up based on the most recent announcements for forest biorefinery projects in North America [19]. The result of this second step was a list of multi-

Fig. 5. Trade-off methodology and roll-out pulpandpapercanada.com

PEER REVIEWED disciplinary criteria that could be employed in the last step of the methodology for decision-making.

The objective of the third step was to carry out a MCDM panel in order to discuss and interpret all criteria and subsequently weight them [20]. The panel consisted of experts knowledgeable in different aspects of the forest biorefinery. The processes were reviewed in detail, and the methodology and criteria were discussed with the panel in order (1) to validate the criteria, (2) to reformulate their “practical” definition in some cases, and (3) to agree on the interpretation of the criteria with the goal of increased consensus among the panel members during the criteria evaluation. The weighting was actually done twice in order to revise and fine-tune criteria for a better analysis and consensus.

Then, criteria weights were determined using a “trade-off” method [21] (see Fig. 5). The main objective of this multi-criteria decision-making (MCDM) activity is to identify among a set of criteria which one is the most important criterion according to panel members, and then compare this most important criterion to all the other criteria in order to weigh them. Once the criteria weights had been established, technologies were evaluated [21]. The result of this last step was a scoring of the biorefinery technologies based on the preferences of the panelists.

RESULTS AND DISCUSSION

Eight criteria were identified for the analysis of the bioethanol process technologies, whose definitions are summarized in Table

III. Two of the criteria were related to profitability of the technology, and another two to product considerations. One criterion was directly related to environmental issues while other criteria were related to the evaluation of the technology itself and its potential integration in a pulp and paper mill.

After significant analysis and discussion, good consensus was obtained concerning the criteria definitions through important suggestions from the panel. For example: • The feedstock flexibility criterion first considered feedstock families (e.g., wood, agricultural residuals, MSW, etc.) equally, without differentiating between biochemical and thermochemical applications. This was changed in order to consider location availability, volume and quality related to the process being considered.

• The criterion regarding new products was changed from “product centric” in order to specifically identify new products to “platform centric” in order to identify the potential for making new products from either syngas/sugars/lignin platforms.

MCDM PANEL RESULTS

Several conclusions were drawn from the MCDM results, which have been summarized in Fig. 6.

• According to the panel members, the adjusted ROI based on a “principles of operation” analysis of each technology was the most important criterion. This analysis involved validating in more detail ROI information released by technology providers. It underlined the challenge

Fig. 6. Weighting results from MCDM panel pulpandpapercanada.com

related to calculating an ROI for different technologies in order to compare them on a similar basis.

• The energy metric and especially the integration potential with the retrofit mill being considered was also found to be important. This underlined the need to create a value from energy management during biorefinery process implementation, which at the same time will reduce operating costs of the core pulp and paper products.

• Feedstocks account for a significant part of manufacturing costs, especially in the case of commodity biorefinery chemicals such as ethanol. The flexibility of a technology for processing different feedstocks was thus expected (before the panel) to be important. However, this was not reflected by the weight attributed to this criterion by the panelists.

• Compared to other criteria, it was found that the environmental criterion had the lowest level of consensus among panel members, perhaps underlining the need to define clearly the importance of this ­criterion as a “show-stopper” for biorefinery technology selection.

These criteria and their interpretation were developed for (a) the context of commodity fuel-grade bioethanol production, and (b) the context of the hypothetical mill. It is important to note that the results would be different for the case of evaluating a different biorefinery option such as the production of an added-value chemical. Selecting other panel members would also have led to different results, depending on the expertise and opinion of

Fig. 7. Ethanol-producing technology rankings May/June 2010 PULP & PAPER CANADA

27

T45

T46

ETHANOL

Table III.: Criteria definitions employed for technology evaluation Criteria

“Ideal definition”

“Practical definition” used for evaluation

Panel elaboration on interpretation

Metric

Return On Investment

Evaluate the profitability in the short term considering global revenues from products with fluctuation in market prices, investment/ operating costs and depreciation

Estimate of the profitability based on overall revenues, published operating/capital costs

- Higher technology risk would demand a higher ROI from the perspective of investors - Be cautious with providers cost projections

ROI: %

Adjusted ROI

Evaluate the profitability with global revenues from all products considering fluctuation in market prices, adjusted investment/operating costs based on efficiency improvements and depreciation

Estimate the profitability by correcting published capital and operating costs based on the identification of potential efficiency improvements

- Criterion is an “equalizer” to adjust levels of optimism in the technology supplier outlook - Reflect the improvement in capital/operating cost moving forward to future implementations

ROI: %

Feedstock flexibility

Identify among all feedstocks listed and related to biorefinery technologies which ones have been successfully processed by the technology

Number of feedstock categories that have been tested and could successfully be processed by the technology

- Importance of having multiple feedstocks to significantly reduce feedstock costs, especially for commodity biorefinery strategies such as ethanol

Feedstock flexibility score

Technology risk

Evaluate the maturity by completing an analysis of principles of operation (POO) for each process unit, and identify bottleneck units where improvements are needed to improve overall maturity and lower significant risk

Evaluation of the development scale or “maturity” of the technology, established by analyzing each one of its unit operation

- This maturity evaluation is rapidly changing with time as technologies progress really fast - Consider the metric as a distance to full scale measurement for biorefinery technologies

Maturity score

Energy and integration

Calculate the global energy efficiency of the technology and quantify its impact on the existing energy profile of the P&P process to evaluate the new common energy profile

Evaluation of the net energy requirement compared to the corn route, and the potential for energy integration into a pulp and paper mill

- Real opportunity for P&P companies to use their lowgrade energy in another way and implement a biorefinery technology - Advantage compared to a Greenfield process.

Energy and integration score

Products and revenue diver- Evaluate the potential of the sification product family for entering the bioproducts market by considering for each product inside the family all potential substitution/ replacement applications with corresponding market demand and prices

Evaluation of process revenues compared to the corn route and analysis of the degree of diversification of revenue streams and market volatility

- Money from new products relatively to money from conventional P&P products is essential.

- Reduced number of products is needed at first to capture the market understanding

Products score

Potential for additional products

Identify interesting derivatives to reach in the green products market for various applications (substitution vs. replacement), types of products (specialty vs. commodity) and evaluate the potential to add them to the product family

Evaluation of the potential of each technology to produce other added-value organic derivatives for the green products market

- 100 % ethanol might not always be a relevant strategy especially in the long term - Use technology versatility for product development represents a good biorefinery strategy.

Market potential score

Potential environment impact

Make a complete “cradle to grave” LCA analysis related to each FBR technology to evaluate their global environmental impact

Qualitative analysis of the impacts on the environment using LCA-oriented categories

- No company would embark on a biorefinery project that is environmentally worse than standards - GHG emissions/land use are critical to consider

Impact score

28

PULP & PAPER CANADA May/June 2010

pulpandpapercanada.com

PEER REVIEWED panel members. The panelists were chosen because of their knowledge in the biorefinery and P&P sector, ensuring the understanding of the main stakes to consider.

The degree of understanding of key issues improved significantly between panel members during the panel execution, and with this, the final panel results showed a high level of consensus between panel members, and consistency within the results of individual panel members for the different criteria. Even though the results would be different for different scenarios, companies can effectively use the MCDM approach for biorefinery decision-making under high uncertainty and different process information.

RANKING BIOREFINERY TECHNOLOGIES

The decision weights and the criteria metric values for each technology were used to rank the biorefinery process technologies (Fig. 7). The criteria with the greatest weights (i.e. techno-economic criteria and energy-related criteria) are logically the biggest contributors to the overall score, however to a greater or lesser extent, both highly weighted and lower weighted criteria were responsible for contributing to differences between technology scores. For example, feedstock flexibility and potential for new products had a significant impact despite their lower weights since these criteria have a high variation in flexibility and product potential among the technologies.

It was found that scarce information about GHG emissions and difficulty to analyze the impacts from land use by different process technologies resulted in significant uncertainty and this was reflected by a low contribution to the final score. It is expected that their importance will be clearer at a more detailed design stage, where the specific situation of the project will be taken into account.

The selected biochemical technologies had overall scores (weights x calculated values for each technology option in the design context) between 0.45 and nearly 0.8. Technology E, representing the Value Prior to Pulping (VPP) technology, showed the best economic results, but must be taken with caution as they are results of a simulation study interpreting smaller scale test results. This technology thus had the lowest development scale and the lowest score when not considering pulpandpapercanada.com

the economics. The next most promising biochemical technology is the Organosolv technology (Technology D) having relatively good economics, a good potential energy integration profile, and interesting results for both revenue diversification and product development. Biochemical technologies have good potential in both the short term, with energy integration and diversified revenues, and in the long term, with the potential for new value-added products other than ethanol based on their sugar platform.

For the high-severity gasification process (Technology F) the most important process step is the gas phase fermentation and it was considered that any gasification process would suffice, whereas for the lowseverity gasification process (Technology G) the gasification technology is the main process step and it was considered that any Fischer-Tropsch technology could be used to manufacture products. These two technologies were given the highest overall score even if each has different strengths.

Technology G has strong economics and a high potential for energy integration.

Technology F could focus on new product development with the gas phase fermentation and has a good potential for reducing operating/capital costs using new separation/purification tools. Thermochemical technologies show interesting economic attractiveness and maturity in the short term for ethanol production, while also having strengths due to their feedstock flexibility.

When compared to each other, biochemical and thermochemical technologies show specific advantages concerning ethanol production. Besides a good potential to be economically successful, higher feedstock flexibility combined with more advanced technology development is advantageous for thermochemical technologies. On the other hand, biochemical technologies show good potential for energy integration and a significantly higher potential for the production of value-added chemicals over the next few years.

CONCLUSIONS

Given the dynamic and rapidly evolving bioethanol sector, selecting a technology strategy is a non-trivial decision for a forestry company. Process technologies should be screened out before the early stage design analysis is undertaken,

by using a systematic methodology that includes the use of multiple evaluation criteria based on widely-available information in order to provide efficient decision support. A set of evaluation criteria and assessment methodology has been presented in this paper. The defined criteria identified address strategic considerations related to the forest biorefinery implementation at the early stage of selecting technologies.

Not surprisingly, the weighting results based on the preferences of the MCDM panelists show that techno-economic criteria are the most important for decisionmaking. These results may have been different if done with another panel or by a forestry company having different strategic priorities for implementing the biorefinery.

Thermochemical processes show good economic attractiveness and feedstock flexibility relative to biochemical processes, and were considered to be at a more advanced technology development stage.

On the other hand, biochemical technologies may be of interest for energy integration, and the future development of other value-added products.

This survey of emerging biorefinery technologies to produce ethanol is a case study which can serve as the base of a methodological “tool” for screening biorefinery technologies. Initial criteria weights would be set by a company according to the described analysis. New options or emerging biorefinery technologies can then be addressed quickly and compared to the ones already analyzed in order to identify its advantages compared to other technologies, which can help forestry companies to make more effective decisions at the early stage of design, as well as to address new technologies that will inevitably be proposed and developed in the coming years.

ACKNOWLEDGMENTS

We would like to thank our panel members for their valuable time and frank opinions. This work was supported by the Natural Sciences Engineering Research Council of Canada (NSERC) Environmental Design Engineering Chair at École Polytechnique in Montréal.

LITERATURE

1. WISING, U., STUART, P. Identifying the Canadian Forest Biorefinery, Pulp and Paper Canada, 107(6): 25-30, 2006.

2. CHAMBOST, V. MCNUTT, J., STUART, P. R. Guided Tour: Implementing the Forest Biorefinery (FBR)

May/June 2010 PULP & PAPER CANADA

29

T47

T48

ETHANOL at Existing Pulp and Paper Mills, Pulp and Paper Canada, 109 (7-8): 19-27, 2008.

3. AMIDON, T. E., WOOD, C. D., SHUPE, A. M., WANG, Y., GRAVES M., LIU S. Biorefinery: Conversion of Woody Biomass to Chemicals, Energy and Materials, Journal of Biobased Materials and Bioenergy, 2 (2):100-120, 2008.

4. LORENTZEN, A. Ethanol Makers Join Food Vs. Fuel Debate, The Washington Post, 2007. [Online]. Available: http://www.washingtonpost.com/wpdyn/content/ article/2007/08/02/AR2007080200249.html.

5. BADGER, P. C. Ethanol From Cellulose: A General Review, Trends in New Crops and New Uses, ASHS press, Alexandria, 2002.

6. CHAMBOST, V., EAMER, B., STUART, P. Forest Biorefinery: Getting On With the Job, Pulp and Paper Canada, 108(2): 19-20, 22, 2007.

7. JANSSEN, M., CHAMBOST, V. STUART, P. R. Successful Partnerships for the Forest Biorefinery, Industrial Biotechnology, 4(4): 352-362, 2008.

8. American Forest and Paper Association, Agenda 2020 Technology Alliance: The Role of Rural America in Enhancing National Energy Security, Technical Report, 2007.

9. www.biofuelsdigest.com, 50 Hottest Companies in Bioenergy 2009-2010, Technical Report, 2009. [On line].

Available: November 2009.

10. THORP, B. A. Comparison of Five Cellulosic Biofuel Pathways, TAPPI Bioenergy Technologies Quarterly, vol.

First Quarter 2010, pp. 23-30, 2010.

11. JOHNSTON, B., JOHNSTON, T., SCOTTKERR, C., REED, J. The Future is Bright, Pulp & Paper International, October 2009, 2009.

12. Wooley, R., Ruth, M., Sheehan, J., Ibsen, K. Lignocellulosic Biomass to Ethanol Process Design and Economics Utilizing Co-Current Dilute Acid Prehydrolysis and Enzymatic Hydrolysis Current and Futuristic Scenarios, Biotechnology Center for Fuels and Chemicals, Technical Report, 1999.

13. VAN HEININGEN, A. Converting a Kraft Pulp Mill Into an Integrated Forest Biorefinery, Pulp and Paper Canada, 107(6): 38-43, 2006.

14. FREDERICK, W. J., JR., LIEN, S. J., COURCHENE, C. E., DEMARTINI, N. A., RAGAUSKAS, A. J., LISA, K. Production of Ethanol from Carbohydrates from Loblolly Pine: A technical and Economic Assessment, Bioresource Technology, 99: 5051-5057, 2008.

Events

Zellcheming Annual General Meeting & Expo June 29-July 01, 2010 Wiesbaden, Germany zellcheming@zellcheming.de, www.zellcheming.com

15. LARSON, E. D., CONSONNI, S., KATOFSKY, R. E., LISA, K., FREDERICK, W. J. A Cost-Benefit Assessment of Gasification-Based Biorefining in the Kraft Pulp and Paper Industry, Princeton University, Technical Report, 2006.

16. HYTÖNEN E., STUART, P. R. Integrated Bioethanol Production Into an Integrated Kraft Pulp and Paper Mill: Techno-economic Assesment, Pulp and Paper Canada, 110(5): 25-32, 2009.

17. STUART, P. R. The Forest Biorefinery: Survival Strategy for Canada’s Pulp and Paper Sector?, Pulp and Paper Canada, 107(6): 13-16, 2006.

18. HOFFMANN, V. H., HUNGERBUHLER, K., MCRAE, G. J. Multiobjective Screening and Evalua-

tion of Chemical Process Technologies, Industrial and Engineering Chemistry Research, 40(21): 4513-4524, 2001.

19. “Verenium optimizing Jennings Demo Plant, Plans 2011 Production Date for Higlands Commercial BIorefinery,” TAPPI Bioenergy Technologies Quarterly, Second Quarter 2009, pp. 3-5, 2009.

20. ANANDA, J., HERATH, G. A Critical Review of Multi-criteria Decision Making Methods with Special Reference to Forest Management and Planning, Ecological Economics – Elsevier, 2009.

21. SEPPÄLÄ, J. Life Cycle Impact Assesment Based On Decision Analysis, Helsinki University of Technology, Helsinki, 2003.

Résumé:

Le développement du concept de bioraffinage forestier utilisant des matières premières lignocellulosique pour la production d’éthanol de seconde génération semble prometteur, en particulier pour les compagnies forestières. Ainsi, de nombreuses technologies émergent actuellement dans ce secteur. Le choix d’une de ces technologies de bioraffinage, à une étape préliminaire de conception, peut s‘avérer difficile du fait de l‘inexactitude et du manque d’informations données par ces fournisseurs de technologies sans oublier d’autres facteurs propres à l’implantation industrielle du bioraffinage forestier. L’objectif de cet article est de définir et de pondérer différents critères spécifiques pour l’évaluation du potentiel des technologies de bioraffinage en cours de développement pour la production de bioéthanol. Différents facteurs technologiques furent considérés, notamment reliés aux rendements et à la rentabilité. D’autres critères comme la flexibilité d’utilisation de diverses sources de matières premières, plus orientés sur la conception de procédé furent également utilisés. Comme attendu, les résultats de notre panel d’AMCD (Analyse Multicritères Décisionnelle) montrent une prépondérance des critères économiques ainsi que ceux reliés à l’intégration technologique dans un contexte industriel déjà existant.Appliqués aux sept procédés de bioraffinage forestier sélectionnés pour l’étude, ces critères montrent que les technologies biochimiques et thermochimiques possèdent leurs propres avantages compétitifs aussi bien à court que long terme. Cependant, les voies thermochimiques ont globalement montré de meilleurs résultats pour la production de bioéthanol.

Keywords: PROCESS DESIGN, PRODUCT DESIGN, FOREST BIOREFINERY, LIGNOCELLULOSIC ETHANOL, MULTI-CRITERIA DECISION-MAKING (MCDM)

Reference: COHEN, J., JANSSEN, M., CHAMBOST, V., STUART, P. Critical Analysis of

Emerging Forest Biorefinery (FBR) Technologies for Ethanol Production, Pulp & Paper Canada, 111(3): T42-T48, May/June 2010. Paper presented at the PAPTAC Annnual Meeting in Montreal, Que., February 2-3, 2010. Not to be reproduced without permission of PAPTAC. Manuscript received and approved for publication by the Review Panel on April 22, 2010.

Progress in Paper Physics Seminar June 7-10, 2010 Montreal, Que. Norayr Gurnagul, 514-630-4101, ex 2241, Norayr.gurnagul@fpinnovations.ca, www.paprican.ca

PacWest Conference June 9-12, 2010 Kamloops, B.C. Mary Barnes, barnesmm@shaw.ca; www.pacwestcon.net

China Paper Shanghai Sept. 15-17, 2010 Shanghai, China www.chinapaperexpo.com

Control Systems 2010 Sept. 15-17, 2010 Stockholm, Sweden SPCI & Innventia, www.controlsystems2010.com

Send events info and news announcements to media@pulpandpapercanada.com 30

PULP & PAPER CANADA May/June 2010

pulpandpapercanada.com

BIOREFINERY

Analysis of a Biorefinery Integration in a Bisulfite Pulp Process

By Z. Périn-Levasseur, F. Maréchal, and J. Paris Abstract: Process integration techniques have been applied to study a bisulfite mill which produces pulp and three additional by-products: bioethanol, lignosulfonate and yeast. Particular attention was devoted to the integration of the chemical recycling loops which have a significant impact on the process energy balances and therefore influence the choice of biorefinery integration strategies. This analysis illustrates the trade-off between conversion of materials and of energy and shows the importance of considering simultaneously the heat recovery through heat exchangers and the combined heat and power production.

E

nergy cost is a significant factor in the overall economics of a pulp and paper (P&P) process. Increasing energy prices and restrictive environmental regulations have motivated the P&P industry to seek energy cost reductions by improving the energy efficiency of its operations. Another concern of the P&P industry is the competition for the resources utilization: wood can be used as an energy resource or to produce bio-materials as well as the raw material to produce P&P. The retrofit implementation of biorefining technologies in kraft P&P mills can be a promising solution to revitalize the industry by producing biofuels and value-added bio-materials while maintaining its core production of pulp and paper [2].

There are different pathways to produce biomaterials from lignocellulosic feedstocks (LCF).

Lignin can be extracted from the residual black liquor and burned to produce heat, cleaned to be sold directly, or even be gasified to produce gas and electricity. Bioethanol, furfural, xylitol, and other chemical intermediates can be produced from the hemicellulose extraction.

Residual biomass can be gasified to produce syngas that could be transformed to produce chemicals and green diesel. Producing bio-materials implies energy consumption and production of waste heat. The energy management cannot be dissociated from the biorefinery integration in a P&P mill: both energy and mass integration must be considered. The aim of this work is to present a study that couples an energy efficiency analysis methodology to a biorefinery integration.

We propose to demonstrate the application of process integration techniques to study the tradeoff between conversion of lignocellulosic materials into bio-materials and energy. pulpandpapercanada.com

METHODOLOGY

Reducing energy consumption in the P&P industry can lead to considerable cost savings. The three main points to consider when implementing an energy efficiency program in a mill are the reduction of the energy requirement, the energy recovery, and the efficient integration of the energy conversion system.

This analysis leads to the definition of an energy efficiency road map with the evaluation of the energy savings and the related investment costs. Due to the high level of integration of a P&P process, no single method can cover the spectrum of tasks to be accomplished; a spectrum of computer-aided process engineering tools must be used. Mill-wide process simulation combined with the application of process integration tools, such as pinch analysis, is the key for reaching the energy savings target. A comprehensive computeraided methodology to analyze the integration of utility systems and energy conversion technologies has been developed. Its goal is the identification of energy savings options by means of process integration and thermo-economic optimization techniques.

It has been applied to a calcium bisulfite pulp mill which produces cellulose as a main product.

This cellulose is used for pulp making, as chemical intermediate and as plastic moulding. The mill functions also as a biorefinery unit which manufactures yeast, ethanol, and lignosulfonates, as well as fuel for the main mill boiler. Figure 1 illustrates the treatment of the waste liquor from the pulping process.

Waste liquor can be either evaporated and burned in a recovery boiler to produce steam, sold as lignosulfonates, fermented and distilled to produce ethanol, or fermented, evaporated and steril-

Z. PÉRIN-LEVASSEUR Natural Resources Canada, CanmetENERGY, Varennes, Que., formerly Ecole Polytechnique Fédérale de Lausanne, Laboratoire d’Energétique Industrielle, Switzerland

F. MARÉCHAL Ecole Polytechnique Fédérale de Lausanne, Laboratoire d’Energétique Industrielle, Switzerland

J. PARIS Ecole Polytechnique de Montréal, Department of Chemical Engineering, Canada

May/June 2010 PULP & PAPER CANADA

31

T49

T50

BIOREFINERY Table I. Actual production and maximum production capacity of the waste liquor usage per ton of cellulose produced (tcp) Usage

Production (t/tcp)

Max capacity (t/tcp)

0.959 0.738 0.0738 0.0464

1.014 0.937 0.103 0.0546

Burned Lignosulfonates Ethanol Yeast

Fig. 1. Simplified process diagram.

ized to produce yeast. Both energy and mass integration must be considered. For example, when lignosulfonates are produced, less sulfur is recycled with the waste liquor and additional sulfur must be purchased. This has an effect on the cost of the products but also on the energy efficiency.

Table I shows the distribution of the waste liquor burned in the recovery boiler and used to produce the by-products and the maximum production capacity of each unit. To determine a tradeoff between conversion of material and minimization of energy consumption, five scenarios have been developed.

• The nominal scenario (1) or the reference case.

• The integrated scenario (2) or the reference case after heat recovery and combined heat and power energy integration.

• The net profit maximization scenario (3) gives the optimal use of the waste liquor from an energy point of view to maximize the net profit.

• The ethanol scenario evaluates the energy recovery and the efficient integration of the energy conversion system with maximum production capacity (4a) and without (4b) ethanol production.

• The maximum waste liquor combustion scenario (5) is defined by the maximum waste liquor burning rate achievable in the recovery boiler. The scenario that would completely eliminate the recovery boiler (no waste liquor burned) is discarded since the actual installations cannot support the treatment of the liquor supplement that may result.

A systematic definition of the process heat transfer requirement defined as hot and cold streams in the process has been developed in order to compute the minimum energy requirement for all scenarios. For the steam consumption sections, the process requirements have been defined by means of the multiple representations concept [1]: the energy requirement defined by the heat-temperature profiles of each process unit is systematically analyzed at three levels: the thermodynamic requirement or the heat transfer required by the process unit, the technological requirement or the way they are satisfied by the technology that implements the operation and finally the utility requirement or the way they consume the distributed energy. Defining a given process unit requirement from the different temperature-enthalpy profiles helps to identify possible energy savings with different levels of process modifications. The analysis is completed by identifying the energy that could be recovered from waste streams and by heat exchanged between mill sections.

The scenarios were evaluated using all representations. The utility representation [U] with limited modifications of the process units and the thermodynamic representation [R] including a detailed analysis of the possible heat exchanges are presented.

32

PULP & PAPER CANADA May/June 2010

Table II. By-products repartition per ton of cellulose produced (t/tcp) Sc.

1* 2 3 4a 4b 5 *Identifcation

Burned (t/tcp)

Ligsulf. (t/tcp)

0.959 0.959 0.641 0.641 0.753 1.107 code is also used

0.937 0.937 1.011 1.011 1.011 0.551 for Table III and

Ethanol (t/tcp)

Yeast (t/tcp)

0.0738 0.0738 0.1033 0.1033 0 0.1033 Fig. 2.

0.0464 0.0464 0.0547 0.0547 0.0547 0.0547

Mass integration models

Using flowsheeting models, the heat requirements in the different by-product lines were computed as a function of the by-product flowrates. Table II shows the by-product distribution for the five scenarios.

This was done by taking into account the maximum production capacity of each by-product, as defined in Table I. The following mass balance constraints were introduced to model the flow distribution of the total waste liquor available ( m˙ wlt ) to be burned in the recovery boiler (m˙ b ), transformed in lignosulfonates ( m˙ l ), ethanol ( m˙ e ) or yeast ( m˙ y ). A second equation gives the amount of sulfur required by the process to produce the cooking acid (m˙ rp ) as a function of the sulfur recovered from burning the waste liquor (m˙ sb ) and of the sulfur entering the sulfur boiler (m˙ seb ).

The biorefinery mass balances are added as linear constraints in the process integration model that is solved by MILP [1]. m˙ b + m˙ l + m˙ e + m˙ y = m˙ wlt

(1)

m˙ sb + m˙ seb = m˙ rp

(2)

In order to compare and evaluate the relevance of the proposed scenarios, the operating cost was computed by equation 3, as a function of the mass flowrate (m˙ ), electricity power (Ė) and cost (C) of imported steam (s), purchased fuel (f ) and electricity (e) for an operating time (time) of 8000 h/y from which the revenue from selling the by-products is deducted.

Cop = m˙ s Cs + m˙ f Cf + ĖCe) * time

(3)

RESULTS

Three performance indicators were evaluated: • Energy is the savings percentage achievable on the energy bill in comparison to the reference case.

• By-product is the profit percentage realized if all bio-materials are sold at the market price in comparison to the reference case.

• Net profit is the difference between the energy and by-product pulpandpapercanada.com

PEER REVIEWED Table II. By-products repartition per ton of cellulose produced (t/tcp) Sc.

Burned (t/tcp)

1* 2 3 4a 4b 5 *Identification

Ligsulf. (t/tcp)

0.959 0.937 0.959 0.937 0.641 1.011 0.641 1.011 0.753 1.011 1.107 0.551 code is also used for Table III and

Table III: Energy, by-products and net profit difference in comparison to the reference case (1)

Ethanol (t/tcp)

Yeast (t/tcp)

0.0738 0.0738 0.1033 0.1033 0 0.1033 Fig. 2.

0.0464 0.0464 0.0547 0.0547 0.0547 0.0547

percentages.

Energy, by-products and net profit percentages have been evaluated and compared to the reference case (1) for all scenarios (2,3,4a,4b,5) in both energy requirement representations ([R],[U]) (Table III). For example, the integrated scenario in thermodynamic representation (2[R]) shows an energy savings of 52% on the energy bill in comparison to the reference case.

The net profit percentage is illustrated in Fig. 2.

There is a clear biorefinery integration strategy emerging from the results: the mill should push the ethanol production to its maximum. The ideal scenario (3) and the maximum ethanol production scenario (4a) show the best net profit (67% for [U] representation, i.e limited modifications of the process units)).

The scenario without ethanol production (4b) is less advantageous (30% for [U] representation) but still better than the reference case or the integrated scenario (2) (17% for [U] representation). Finally, burning the maximum waste liquor that the recovery boiler can support (5) is not a judicious strategy, since it gives the lowest net profit percentage of all the scenarios (2% for [U] representation).

The analysis of the minimum energy requirement of the process computed for the different requirement representations ([R], [U]) provides other interesting results. Using heat cascade MILP models, the energy savings through heat recovery within and between sections have been quantified in terms of fuel consumption and optimal combined heat and power production.

The energy saving and net profit percentages are always higher in the [R] representation than the [U] representation for all the scenarios. It should be noted that switching from utility to thermodynamic representation requires equipment modifications and investment. Therefore a systematic analysis of the required modifications has been done to identify the configuration that would have the higher impact on the energy requirement.

CONCLUSIONS

The goal of this work was to couple conversion of bio-materials and energy efficiency analysis. An analysis of the energy/biorefining products trade-off has been done. The implementation of biorefinery has been discussed in terms of system and energy impacts. Trends for biorefinery strategies in the P&P industry are introduced: • Increased heat recovery potential leads to higher energy savings.

• The cost of energy penalty is compensated by the increase income from selling a value-added bio-product, in this case ethanol.

• Burning additional liquor reduces bio-products production and therefore net profit despite the reduction of the energy bill.

• In the present market conditions, burning waste liquor is less pulpandpapercanada.com

Sc. 1 2[R] 2[U] 3[R] 3[U] 4a[R] 4a[U] 4b[R] 4b[U] 5[R] 5[U] *Effect: +++

Energy (%)

By-products (%)

Net profit (%)

reference reference reference 52 +++* 0 29 ++ 31 ++ 0 17 + 39 ++ 37 ++ 80 +++ 17 + 37 ++ 67 +++ 39 ++ 37 ++ 80 +++ 17 + 37 ++ 67 +++ 48 +++ 10 + 42 ++ 26 + 10 + 30 ++ 54 +++ –11 – 13 + 35 ++ –11 – 2 very high, ++ high, + moderate, – negative

Fig. 2. Net profit difference for each scenario in comparison to the reference case (1).

attractive than producing bio-products.

This study emphasizes that the efficient energy conversion is crucial for the biorefinery implementation in a chemical pulp mill.

ACKNOWLEDGMENTS

This work was made possible by a grant from the Swiss Federal Office of Energy (SFOE) which is gratefully acknowledged.

LITERATURE

[1] D. BROWN, F. MARECHAL, and J. PARIS. A Dual Representation for Targeting Process Retrofit, Application to a Pulp and Paper Process. Applied Thermal Engineering, 25(7 SPEC. ISS.):1067-1082, 2005.

[2] A. VAN HEININGEN. Converting a Kraft Pulp Mill into an Integrated Forest Biorefinery. Pulp and Paper Canada 107(6):38-43, 2006.

Résumé :

Un outil d’intégration de procédés a été appliqué pour étudier une usine produisant de la pâte au bisulfite de calcium et trois produits additionnels : du bioéthanol, des lignosulfonates et des levures. Une attention particulière a été consacrée à l’intégration des boucles de recirculation des produits chimiques qui ont un impact significatif sur les bilans d’énergie et qui influencent le choix des stratégies d’intégration du bioraffinage dans une usine de pâte et papier.

Cette étude illustre le compromis qui peut exister entre la conversion des matériaux et de l’énergie et montre l’importance de considérer simultanément la récupération de chaleur à travers des échangeurs de chaleur et la production combinée.

Keywords: ENERGY INTEGRATION, BIOREFINERY, PULP AND PAPER, ENERGY EFFICIENCY, ENERGY SAVINGS

Reference: PERIN-LEVASSEUR, Z., MARECHAL, F., PARIS, J.

Analysis of a Biorefinery Integration in a Bisulfite Pulp Process. Pulp & Paper Canada 111 (3): T49-T51 (May/June 2010). Paper presented at the 2009 PAPTAC Annual Meeting in Montreal, QC, Canada, February 3-4, 2009.

Not to be reproduced without permission of PAPTAC. Manuscript received October 08, 2028. Revised manuscript approved for publication by the Review Panel March 29, 2010.

May/June 2010 PULP & PAPER CANADA

33

T51

T52

ENERGY EFFICIENCY

Energy Implications of Water Reduction Strategies in Kraft Process.

Part I: Methodology

By E. Mateos-Espejel, M. Marinova, S. Bararpour and J. Paris Abstract: A new systematic methodology has been developed to study interactions between water and energy in the kraft pulping process and has been applied to an operating mill. The methodology which can be used to find appropriate strategies for water consumption reduction and which also considers their impacts on the thermal energy efficiency of the process is described in Part I of this paper. A case study was subsequently performed and the results are presented in Part II.

T

he pulp and paper industry is among the largest consumers of energy and water. Rising energy costs and more stringent environmental regulations have led the industry to refocus its efforts towards identifying ways to improve energy and water conservation. Energy and water aspects are usually analyzed independently but in reality they are strongly interconnected. In a typical kraft process, the larger the amount of water consumed and effluent produced, the larger the energy required for heating, cooling and pumping, therefore it is important to consider energy and water interactions.

Most of the studies on the energy efficiency of the kraft process are based on Pinch Analysis®.

Energy savings strategies which deal with heating and cooling requirements, power generation, depressurization and fuel utilization are proposed [1, 2]. On the other hand, for reducing the water consumption, research efforts have focused on the development of process design methodologies.

They cover a variety of techniques, ranging from graphical-based approaches such as the sourcesink method [3, 4], to mathematical optimization-based approaches [5, 6]. Attempts to study the possible synergistic effects between energy and water have been reported. Schaareman et al.

[7] applied thermal Pinch Analysis® and Water Pinch® in sequence, without analyzing the thermal effects of the water reduction projects. Savulescu et al. [8] suggested a combined water and energy analysis for application in water networks, based on a set of two-dimensional diagrams. Lafourcade et al. [9] proposed a methodology where the closure strategies are figured out from thermal Pinch Analysis®.

The purpose of this work was to develop a methodology which considers the energy implications of water reduction strategies in the energy 34

PULP & PAPER CANADA May/June 2010

efficiency of a kraft mill, taking into account their mutual constraints. This methodology uses process integration tools such as the water-thermal composites curves [10], the water sources and sinks curves [3] and the thermal Pinch Analysis®.

The methodology consists of the following steps: Step 1. Analysis of the current water utilization in the process.

Step 2. Benchmarking water consumption to evaluate the opportunities for water savings.

Step 3. Thermal analysis of the network is carried out, followed by the identification of water restrictions to be considered when proposing water reduction strategies. A computer simulation of the strategies is done in order to realize the operating condition changes in the complete process.

Step 4. The energy implications of water closure on the internal heat recovery are measured.

Step 5. Trade-off analysis.

E. MATEOS-ESPEJEL Department of Chemical Engineering, École Polytechnique, Montréal, Canada

M. MARINOVA Department of Chemical Engineering, École Polytechnique, Montréal, Canada

Methodology

Step 1: Global water network of reference mill The data used in this study were taken from a computer simulation of the studied mill (kraft pulp mill located in Eastern Canada), developed in CADSIM® Plus (Aurel Systems Inc.). The mill has an average daily production of 700 adt/d of high grade bleachable pulp and consumes 83 m3 of fresh water per adt of pulp. About 75% of the feed water is screened and chemically treated for utilization in operations where it is in direct contact with the pulp, such as washing, bleaching, chemicals preparation, pulp machine, or for steam production; this water is called treated water. The remaining 25% is only screened and it is used for indirect cooling, steam scrubbing and house keeping: it is called screened water. The treated and screened water consumptions in the reference mill and the effluents produced are presented in Table I.

S. BARARPOUR Department of Chemical Engineering, École Polytechnique, Montréal, Canada

J. PARIS Department of Chemical Engineering, École Polytechnique, Montréal, Canada pulpandpapercanada.com

PEER REVIEWED Table II. Water consumption and effluent production by department Department

Water used (m3/adt) (Effluent m3/adt)

Treated water Pulp prep. and washing Bleaching Drying Boilers and evaporators Re-caustification Vacuum pumps Chemical preparation Others Screened water Bleaching Re-caustification Chemical preparation Others Total

8.15 24.49 8.93 4.75 2.01 2.37 5.30 4.59

0.67 27.51 5.20 12.79 0.01 2.37 2.72 4.59

0.79 4.55 3.80 13.06 82.80

0.79 4.55 3.80 13.06 78.06

Step 2: Benchmarking: Evaluation of water reduction potential The purpose of this step is to analyze and compare the water utilization in the studied mill for estimating the potential for water reduction. Three reference mills were selected: a state-of-the-art mill, a best-practice mill and an average mill in the 1990s [11, 12]. It can be observed on Fig. 1 that there is potential for water reduction in the case study: 10% of the current water consumption could be saved with respect to the ’90s average mill, 50% with respect to the ’90s best-practice mill and even 80% if compared to the state-of-the-art mill.

As already mentioned, the screened water utilization is mainly for non-process uses, whereas the production and utilization of treated water, as well as the resulting effluents, are associated with the energy needs of the process. For this reason the study on water reduction possibilities has been performed for the treated water only. In the thermal analysis, the energy used for water heating and the usage of water as cooling medium are considered.

Step 3: Water analysis Water network The treated water is used at three temperature levels (Fig. 2): ambient (4°C), warm (44°C), and hot (58 to 71°C). The warm water is generated in the condensers of the black liquor concentration unit. In principle, the mill should only use hot water, but as it does not have the capacity to produce all the hot water needed, warm water is used in some departments. To produce hot water, the temperature of the warm water is increased in three steps, first to 53°C by means of internal heat recovery, then to 62°C using direct steam injection in the hot water tank and, finally, 71°C is reached by indirect heat exchange with steam. Hot water at 58°C is also produced by indirect heat exchange with the evaporators’ condensate.

Water-thermal composites curves In order to identify appropriate strategies for improving water utilization and energy efficiency, it is important to define the quantity of water required for cooling and other process uses [10].

In the actual process, there is no treated or screened water used with the only purpose of cooling; however, the effluents have to pulpandpapercanada.com

Fig. 1. Benchmark comparison: water utilization and effluent production for different mills.

be cooled down to the temperature required in the effluent treatment system (33°C). The effluents produced in bleaching, pulp machine and evaporators departments have an average temperature of approximately 70°C. Their temperature is reduced either by direct mixing with cold effluents from various unit operations where water at ambient temperature is used and by contact to the atmosphere in the clarifiers and the aeration basins.

The water-thermal composite curves are constructed for this purpose. They consist of three curves, a hot composite curve and two cold composites, the process water and the total water. The hot composite curve represents the effluents to be cooled and the steam used to increase the treated water temperature (including the de-aerator); the process water composite curve corresponds to the water that needs to be heated and used directly in the process; and the total water composite curve comprises all the treated and screened water used in the process. The three curves for the mill are presented in Fig. 3.

The difference between the total water and process water composite curves is the water (treated and screened) used at ambient temperature. Therefore, it can be observed in Fig. 3 that all the screened water and part of the treated water at ambient temperature are subsequently used to cool down the effluents; this accounts for half of the cooling requirement. This means that if the water consumption at ambient temperature is reduced, the temperature required in the effluent treatment system may not be reached. It can also be seen that most of the water is used for process purposes rather than for cooling, therefore, the strategies will be directed at reducing warm and hot water which will also affect the steam consumption.

Water source and sinks curves The sources and sinks composite curves are used to maximize the water reutilization within a process. In this study they are constructed to identify strategies for reduction of the treated water consumption.

A basic step is the representation in the purity vs. mass flow rate diagram of the aggregate of all possible mass transfers between water streams. It consists of two composite curves, one for the streams which can be used as water sources (streams that can be re-used) and one for the streams which can be used as water sinks (the water needed by the process). The purity of May/June 2010 PULP & PAPER CANADA

35

T53

T54

ENERGY EFFICIENCY

Fig. 3. Water-thermal composite curves.

Fig. 2. Treated water network of the process.

Fig. 5. Thermal composite curves.

Fig. 4. Water composite curves.

the demands is based on the maximum level of contamination allowable by the process operations to perform correctly their function. In this case, the concentration of dissolved solids (DS) which contain all the contaminants found in process streams was considered as a single contaminant and it was used as indicator to select the appropriate water closure strategies. The maximum level of contamination acceptable for the demand streams was taken from a computer simulation of the current process operation of the reference mill.

The sources and sinks composite curves constructed on Fig. 4 show that the minimum water consumption is 1000 m3/h while the minimum effluent production is 875 m3/h. As a result of this analysis, four options have been identified: • Reuse of condensates from the evaporators in the re-caustification, washing and pre-washing operations.

• Reuse of the whitewater from the pulp machine in the bleaching department.

• Increased reutilization of filtrate from bleaching.

36

PULP & PAPER CANADA May/June 2010

• Reuse of up to 64% of vacuum pumps sealing water which can be done without affecting the performance of the equipment due to an increase in temperature.

These options have been simulated in CADSIM® Plus to determine the energy impacts of their implementation on the process (increase of the effluents temperature, average temperature of the process, and modification of energy demands).

Step 4: Energy implications The energy implications of water reduction strategies are evaluated applying thermal Pinch Analysis® to the complete process.

This approach is applied to maximize internal heat recovery within a process and to minimize the need for hot and cold energy supplied by utilities. Its principles and application have been described in the literature [13]. The cornerstone of Pinch Analysis® is the display in a temperature vs. enthalpy diagram of all possible heat transfers within the process. It consists of the hot and cold composite curves which respectively represent the heat availability and demand in the process and define the minimum energy requirement (MER) and the pinch point. For the current process (before strategies implementation), the thermal composite curves are shown in Figure 5. The minimum heating requirepulpandpapercanada.com

PEER REVIEWED ment (MHR) is 101 MW, the minimum cooling requirement (MCR) is 15 MW and the pinch point is located at 71°C for a ΔTmin of 10°C, typical for this kind of processes [14].

The water reduction strategies may modify the shape of the composite curves, the minimum energy requirements and the pinch point location, thus affecting the process internal heat recovery. The implementation of such strategies produces a four way gain by the simultaneous reduction of cold and hot demands of water consumption and effluent production. The effect on the minimum energy requirement depends on each specific case.

It should not be assumed, however that an increase in MER always creates a corresponding increase in the total process energy demand because of other factors; such a case can be seen in Part II. Furthermore, the pinch point could be modified as the low temperature energy available in the process is reduced. If this is the case, there would be an indirect consequence which may or may not justify the installation of energy upgrading units, like heat pumps that upgrade low temperature energy from below to above the pinch point [15].

Step 5: Trade-off analysis It is important to stress that the temperature of the source streams must be higher than or equal to that of the water currently used. If not, the direct savings may still occur, but the heating demand in other parts of the process may be increased.

For this reason it is important to analyze all impacts of the strategies by computer simulation.

The effects of the implementation of water closure must be quantified and compared with other alternatives in order to evaluate their technical and economic advantages. Such a comparison can be done by analyzing other energy efficiency measures in the process, such as internal heat recovery or integration of energy con-

pulpandpapercanada.com

version or upgrading units. Operability and control aspects could be a technical factor for project selection. Pay-back times could be used as indicators of economic viability assessment.

CONCLUSIONS

A methodology that considers the water and energy constraints when developing water closure scenarios has been proposed and illustrated for a kraft pulping process.

The methodology identifies the tasks that the water performs, process or cooling, as well as strategies for water reduction. By considering the energy in the analysis, it is possible to identify the impact of the strategies, not only on direct energy savings, but also on other potential measures that could be affected by the water reutilization.

An analysis of the results obtained by the proposed methodology is done in the second part of the study.

ACKNOWLEDGEMENTS

This work was supported by a grant from the R&D Cooperative program of the National Science and Engineering Research Council of Canada. The industrial partners to this project and most specially the mill which supplied the data are gratefully thanked. E. Mateos-Espejel receives financial support from the Mexican Council of Science and Technology as a PhD candidate. Thanks are also given to Dr. L. Savulescu (NRCan; CTECVarennes) for her guidance in the water-

energy analysis.

LITERATURE

1. Sarimveis, H.K., Angelou, A.S., Retsina, T.R., Rutherford, S.R., Bafas, G.V., Optimal energy management in pulp and paper mills, Energ. Convers. Manage.

44(10):1707-1718 (2003).

2. Brown, D., Marechal, F., Paris, J., A dual representation for targeting process retrofit, application to a pulp and paper process, Appl. Therm. Eng. 25(7):1067-1082 (2005).

3. Dhole, V.R., Fluid efficiency, U.S. Patent 5,824,888 (1998).

4. Wang, Y.P., Smith, R., Wastewater minimisation, Chem. Eng. Sci. 49(7):981-1006 (1994).

5. Shafiei, S., Domenech, S., Koteles, R., Paris, J., System closure in pulp and paper mills: Network analysis by genetic algorithm, J. Clean. Prod. 12(2):131-135 (2004).

6. Jacob, J., Kaipe, H., Couderc, F., Paris, J., Water network analysis in pulp and paper processes by pinch and linear programming techniques, Chem. Eng. Commun.

189(4):184-206 (2002).

7. Schaareman, M., Verstraeten, E., Blaak, R., Hooimeijer, A., Chester, I., Energy and water pinch study at the Parenco paper mill, Paper Technol. 41(1):47-52 (2000).

8. Savulescu, L., Kim, J.-K., Smith, R., Studies on simultaneous energy and water minimisation - Part II: Systems with maximum re-use of water, Chem. Eng. Sci. 60 (12):3291-3308 (2005).

9. Lafourcade, S., Fairbank, M., Stuart, P., Roadmap to minimum energy and water use for integrated newsprint mills, in Reprints 92nd Annual Meet. of PAPTAC, Book A. Montreal, QC 63 -69 (2006).

10. Alva-Argaez, A., Savulescu, L., Poulin, B., A process integration-based decision support system for the identification of water and energy efficiency improvements in the pulp and paper industry, in Reprints 93rd Annual Meet. of PAPTAC, Book C. Montreal, QC 23 -26 (2007).

11. Turner, P., Water use reduction in the pulp and paper industry, Ed. PAPTAC. Vancouver, BC (1994).

12. Gullichsen, J., Fogelholm, C.-J., Papermaking Science and Technology, Book 6. Published by the Finnish Paper Eng. Assoc. and TAPPI (1999).

13. Linnhoff, B., Townsend, D.W., Boland, D., HEWITT, G.F., Thomas, B.E.A., Guy,A.R., Marsland, R.H., A user guide on process integration for the efficient use of energy, 2nd Ed. IChemE. Rugby, UK (1994).

14. Linnhoff, B., Pinch Analysis - a state-of-the-art overview, Chem. Eng. Res. Des. 71 (A5):503-522 (1993).

15. Bakhtiari, B., Mateos, E., Legros, R., Paris, J., Integration of an absorption heat pump in the kraft pulping process: Feasibility study, in Reprints 93rd Annual Meet. of PAPTAC, Book A. Montreal, QC 235-239 (2007).

Résumé : Une nouvelle méthodologie systématique a été développée pour étudier les interac-

tions entre l’eau et l’énergie dans le procédé kraft et elle a été appliquée à une usine en opération.

La méthodologie qui peut être utilisée pour identifier des stratégies appropriées afin de réduire la consommation de l’eau et qui considère aussi leurs impacts sur l’efficacité thermique du procédé est décrite dans la partie I de ce travail. Une étude de cas a été développée et les résultats sont présentés dans la partie II.

Keywords: KRAFT PROCESS, ENERGY EFFICIENCY, WATER SYSTEM CLOSURE, PINCH ANALYSIS, WATER-ENERGY

Reference: MATEOS-ESPEJEL, E., MARINOVA, M., BARARPOUR, S., PARIS, J. Energy

Implications of Water Reduction Strategies in Kraft Process. Part I: Methodology, Pulp & Paper Canada 111(3):T52-T55 (May/June 2010). Paper presented at the 94th Annual Meeting in Montreal, February 5-7, 2008. Not to be reproduced without permission of PAPTAC. Manuscript received December 17, 2007. Revised manuscript approved for publication by the Review Panel March 29, 2010.

May/June 2010 PULP & PAPER CANADA

37

T55

T56

ENERGY EFFICIENCY

Energy Implications of Water Reduction Strategies in Kraft Process.

Part II: Results

By E. Mateos-Espejel, M. Marinova, S. Bararpour and J. Paris Abstract: A new systematic methodology has been developed to study interactions between water and energy in the kraft pulping process and has been applied to an operating mill. The methodology, which can be used to find appropriate strategies for water consumption reduction and which also considers their impacts on the thermal energy efficiency of the process, has been described in Part I of this paper. A case study was subsequently performed and the results are presented in Part II. Four strategies that simultaneously reduce water, steam and cooling requirements are analyzed. Potential savings are significant.

A

ttempts to reduce the water consumption in the kraft process have been made but without analyzing the global process energy implications of water closure. These strategies have been primarily based on increased reutilization of bleaching filtrate, of whitewater, of condensates from the evaporators and, on the introduction of additional oxygen washing stages [1-3]. The implementation of those water savings measures may have serious effects on the thermal balance of the mill. For example, the steam consumption may be reduced, the cooling demand may be increased and, the effluent temperature may rise. The scope of studies that are usually performed may vary from only water reduction [4] to process integration where energy effects are considered. In a two step procedure Towers [5] first applied Pinch Analysis® to identify opportunities for better energy efficiency, and proposed complementary measures to reduce the water used for cooling by increasing the heat transfer area in the condensers and adding a cooling tower in the water network. Savulescu et al. [3] used Pinch Analysis® combined with water and energy analysis in the water network to improve the energy efficiency. The default (defect???) of those approaches is that they do not consider water as a heat source, and this important element of the thermal problem is often ignored.

The results obtained using the methodology explained in Part I of this work are presented below. The proposed strategies for water savings are analyzed and their energy implications are examined in order to determine the impacts on the global heating and cooling demands, on the minimum energy requirements and, on the pinch point position. The data used in this study were taken from a computer simulation of the studied mill (kraft pulp mill located in Eastern Canada), 38

PULP & PAPER CANADA May/June 2010

developed in CADSIM® Plus (Aurel Systems Inc.).

E. MATEOS-ESPEJEL Department of Chemical Engineering, École Polytechnique, Montréal, Canada

Methodology overview

The methodology presented in Part I consists of 5 steps: Step 1. Analysis of the current water utilization in the process.

Step 2. Benchmarking the water consumption to evaluate the opportunities for water savings.

Step 3. Thermal analysis and identification of restrictions to be considered in the water reduction strategies. These strategies are also computer simulated to identify the impact on the operating conditions of the complete process.

Step 4. Analysis of the energy implications of water closure on the internal heat recovery.

Step 5. Trade-off analysis.

In Part I it has been shown, by means of a benchmarking assessment, that there is a potential to reduce the water consumption in the studied mill. Most of the treated water is used for process purposes rather than for cooling, which has a direct effect on the thermal energy balance of the process. Therefore, it has been decided to focus the study on the reduction of treated water. Sources and sinks composite curves have been constructed in order to identify opportunities for water reutilization. The concentration of the dissolved solids in the water (DS) has been considered as a process demand constraint to be satisfied by water sources.

According to the curves obtained the minimum filtered water consumption is 1000 m3/h and, the minimum effluent production is of 875 m3/h. The following strategies for water reduction have been identified: • Reuse of condensates from the evaporators; • Reuse of whitewater from the pulp machine; • Increased reutilization of bleaching filtrate;

M. MARINOVA Department of Chemical Engineering, École Polytechnique, Montréal, Canada

S. BARARPOUR Department of Chemical Engineering, École Polytechnique, Montréal, Canada

J. PARIS Department of Chemical Engineering, École Polytechnique, Montréal, Canada pulpandpapercanada.com

PEER REVIEWED • Reuse of vacuum pumps sealing water.

The water streams considered for reuse are currently sewered.

The next section presents the description of the proposed strategies for their advantageous utilization.

Strategies for water closure

Reuse of condensates from the evaporators This first strategy deals with the reutilization of the condensate from the evaporators in the re-caustification unit, washing unit and pre-washing step of the bleaching (Fig. 1). These condensates have a zero level of DS but to avoid odour problems the methanol concentration must also be considered as a constraint for reuse. In the current process configuration, the various condensates are mixed. In order to implement the identified strategy they must be segregated in 2 types [6]. The condensates produced in the 2nd to 6th effect of the evaporator trains and the stripped condensate have a low concentration of methanol, therefore, they can be reused in washing-type operations. The condensate produced in the 7th effect has a high concentration of methanol, consequently it is acceptable for reuse in the re-caustification loop but not in washing operations. This strategy saves 350 m3/h (15% of the total) of water and thermal energy savings are also expected.

As the condensate temperature is higher than the temperature of the hot and warm water, the injection of steam in the mixer following the pre-washer could be reduced. Similarly, the temperature increase of the washing filtrate, which is partly reused in the digester, could decrease the digester steam consumption.

Reuse of whitewater Whitewater reutilization in the last stage of the bleaching section is a common practice, but for some washing sequences it can also be done in the other stages [1]. The strategy proposed here (Fig. 2) is to reuse whitewater in the washer of the second bleaching stage, saving 110 m3/h (5% of the total). The reduction of hot water consumption is directly proportional to the low pressure steam utilization, as steam is used to attain the hot water temperature (71°C).

Reuse of bleaching filtrate The studied mill has already accomplished a certain level of closure in the bleaching plant. However, its effluent production of 32 m3/adt is above the Canadian median (28.4 m3/adt) [1], which leaves room for improvement. For example, part of the filtrate from stage 5 is actually reused in stage 3. The new strategy (Fig. 3) considers the further increase the reutilization by 15 m3/h (1% of the total). It would be necessary to relax the mill constraints to enhance even more its reutilization. This would decrease the minimum water consumption and effluent production. However, it would be essential to consider the technical problems which may arise.

Vacuum pumps sealing water In the current process configuration the water from the vacuum pump sealing is used to cool mixed effluents from the process. As a result of the implementation of the strategies previously proposed in this section, the quantity of effluent will be substantially reduced, therefore it will be possible to decrease the consumption of the vacuum pump sealing water. The temperature of the water, pulpandpapercanada.com

Fig. 1. Strategy for reutilization of evaporators condensates.

Fig. 2. Strategy for whitewater reutilization.

Fig. 3. Strategy for bleaching filtrate reutilization.

which must not be above 40°C, is the constraint for the implementation of this strategy. Houle et al. [7] have shown that it is

Fig. 4. Strategy for vacuum pump sealing water reutilization.

May/June 2010 PULP & PAPER CANADA

39

T57

T58

ENERGY EFFICIENCY which must not be above 40°C, is the constraint for the implementaion of this strategy. Houle et al. [7] have shown that it is possible to reuse up to 64 % of the sealing water effluent, without affecting the performance of the equipment. Therefore, 70 m3/h (3% of the total) of water is saved.

Energy implications

The water savings strategies have been introduced in the computer simulation of the studied mill. Their implementation involves modifications in the treated water network of the process which can be noted by comparison of Fig. 5a (which is identical to Fig. 2 of Part I) and Fig. 5b.

The use of make up water in the warm water tank and of LP steam in the hot water tank is no longer needed because of the condensate reuse. The fresh water preheated and used in the prewashing is now replaced by a direct utilization of condensate from the evaporators. The strategies for water reuse also reduce the quantity of warm water required for pulp bleaching and eliminate the warm water use in the re-caustification loop.

As was expected, the implementation of the strategies also impacts the energy requirement of the process. The steam consumption is reduced in the bleaching plant, in the digester, in the de-aerator and in the hot water production. Therefore, less steam needs to be produced and this represents a reduction of 14 MW of the total heat consumption of the mill. The water-thermal composite curves [8] show the reduction of the steam used for water heating and for de-aeration (Fig. 6). The cooling demand is also reduced by 13.1 MW, despite an increase of temperature of the bleaching effluents (+8°C).

The implementation of the water closure strategies has an effect on the thermal composite curves, as can be seen in Fig. 7.

The minimum heating requirement is decreased by 1.1 MW and the minimum cooling requirement is increased by 6.9 MW. The reason for those effects is that in the current configuration all the cooling water used in the condensers of the evaporator trains is reused in the process. This is no longer the case after the implementation of these strategies.

The reduction of the process heating demand results from the elimination of the pinch rules violations. These violations are due to the use of steam below the pinch point for the hot water production, in the pre-washer steam mixer, and in the de-aerator.

After the implementation of the water reduction strategies the pinch point is lowered from 71 to 57 °C because the energy content of the effluents at a low temperature below the pinch point is significantly reduced.

Consequently, if the implementation of energy upgrading or conversion devices (heat pumps, trigeneration units) is envisaged, their installation may be affected, as the temperature of the energy available will be reduced.

After the implementation of the proposed strategies less energy will be utilized in the process. However, other options for improved energy efficiency may not be feasible anymore, therefore, a trade-off analysis is needed in order to evaluate all the thermal effects of the water closure.

Trade-off analysis

A global water-energy scenario which includes all the strategies identified is compared with the results of an optimized heat 40

PULP & PAPER CANADA May/June 2010

Fig. 5a. Treated water network before implementation of water saving strategies.

Fig. 5b. Treated water network after implementation of water saving strategies.

exchanger network (HEN) designed to improve the internal heat recovery within the process [9]. The HX-NET software was used to develop the HEN. The two possibilities have been developed independently and economically assessed using the simple pay back time (PBT) and the following prices: • Steam produced with bunker oil: 25 $/t; • Fresh water: 0.065$/m3; • Effluent treatment: 0.1$/m3.

The water-energy scenario saves water and reduces the efflupulpandpapercanada.com

PEER REVIEWED ent production. As a result the low temperature energy available in the process effluents could be reused. The HEN scenario saves more energy as it enhances the internal heat recovery within the process. The disadvantage of both scenarios is mainly linked to the process modifications to be introduced. On the other hand, water system closure is not compatible with those options in the HEN design that are associated with the hot water production.

The economic analysis shows that both scenarios are feasible, although the water-energy scenario has a lower investment and payback time; the HEN scenario is more interesting in a longterm perspective.

It is evident that both scenarios are compatible, once their interactions have been elucidated. It would be possible to implement them at the same time, but further studies are needed to define the best possible design of water and energy systems in the mill.

Fig. 6. Effect of the water strategies in water-thermal composite curves.

CONCLUSIONS

Four strategies for water reutilization in a kraft pulp mill have been identified and their energy implications have been studied.

The proposed strategies save 540 m3/h (24% of the total) of water, 14 MW of steam, and 13.1 MW of cooling demand. Their energy implications go beyond effluent temperature increase and energy savings, affecting the complete thermal balance of the process, the MER and the pinch point temperature. The water closure strategies must be the core of any process energy optimization project in order to evaluate all the aspects that could be affected and, must be considered in decisions for the implementation in a mill of an optimal energy efficiency strategy.

ACKNOWLEDGEMENTS

This work was supported by a grant from the R&D Cooperative program of the National Science and Engineering Research Council of Canada. The industrial partners to this project and most specially the mill which supplied the data are gratefully thanked. E. Mateos-Espejel receives financial support from the Mexican Council of Science and Technology as a PhD candidate.

Thanks are also given to Dr. L. Savulescu (NRCan-CTECVarennes) for her guidance in the water-energy analysis.

LITERATURE

1. Towers, M., Turner, P.A., Survey of bleach plant washing practices in Canadian mills, Pulp & Paper Canada 99(7):44-49 (1998).

2. Syberg, O., Swaney, J., Vice, K., Russell, W., Water reduction strategies for existing bleach plants, Pulp & Paper Canada 99(7):80-83 (1998).

3. Savulescu, L., Poulin, B., Hammache, A., Bedard, S., Gennaoui, S., Water and energy savings at a kraft paperboard mill using process integration, Pulp and Paper Canada 106(9): 29-31 (2005).

4. Syberg, O., Barynin, J., Impact of water reduction on kraft mill heat balance, in Proceed.

TAPPI Int. Eng. Conf., Part 3. Miami, FL. TAPPI Press, Norcross, GA. (1998).

5. Towers, M., Energy reduction at a kraft mill: Examining the effects of process integration, benchmarking, and water reduction, in Proceed. TAPPI Fall Tech. Conf. Atlanta, GA. TAPPI Press, Norcross, GA. (2004).

6. Gullichsen, J., Fogelholm, C.-J., Papermaking Science and Technology, Book 6. Published by the Finnish Paper Eng. Assoc. and TAPPI (1999).

7. Houle, J.F., Brousseau, Y., Dorica, J., Paris, J., Reduction of fresh water consumption for process and non-process uses in an integrated newsprint mill, in Proceed. of the 84th Annual Meeting of the Technical Section of CPPA, Part A. Montreal, QC (1998).

8. Alva-Argaez, A., Savulescu, L., Poulin, B., A process integration-based decision support system for the identification of water and energy efficiency improvements in the pulp and paper industry, in Reprints 93rd Annual Meet. of PAPTAC, Book C. Montreal, QC (2007).

9. Lutz, E., Identification and analysis of energy saving projects in a Kraft mill, in Reprints 94rd Annual Meet. of PAPTAC, Book C. Montreal, QC (2008).

pulpandpapercanada.com

Fig. 7. Energy implications in the composite curves of the complete process.

Table I. Summary of cost analysis for water-energy and HEN scenarios Scenario

Water-energy HEN

Heating saved (MW)

Cooling saved (MW)

Invest.

(M$)

PBT (a)

14 30

13.1 23

0.2 4

0.1 0.4

Résumé : Une nouvelle méthodologie systématique a été dévelop-

pée pour étudier les interactions entre l’eau et l’énergie dans le procédé kraft et elle a été appliquée à une usine en opération. La méthodologie qui peut être utilisée pour identifier des stratégies appropriées afin de réduire la consommation de l’eau et qui considère aussi leurs impacts sur l’efficacité thermique du procédé est décrite dans la partie I de ce travail. Une étude de cas a été développée et les résultats sont présentés dans la partie II. Quatre stratégies qui réduisent simultanément la consommation d’eau et de vapeur, ainsi que les besoins de refroidissement sont analysées. Le potentiel des économies est significatif.

Keywords: KRAFT PROCESS, ENERGY EFFICIENCY, WATER SYSTEM CLOSURE, PINCH ANALYSIS, WATER-ENERGY Reference: MATEOS-ESPEJEL, E., MARINOVA, M., BARARPOUR,

S., PARIS, J. Energy Implications of Water Reduction Strategies in Kraft Process. Part II: Results, Pulp & Paper Canada 111(3): T56-T59 (May/June 2010). Paper presented at the 94th Annual Meeting in Montreal, February 5-7, 2008. Not to be reproduced without permission of PAPTAC. Manuscript received December 17, 2007. Revised manuscript approved for publication by the Review Panel March 29, 2010.

May/June 2010 PULP & PAPER CANADA

41

T59

INDUSTRY NEWS CORRECTION

News, from page 7

GREEN TRANSFORMATION FUND PROJECTS

KAMLOOPS, B.C. — Domtar Corp. will proceed with two projects to improve energy conservation, increase renewable power generation and reduce particulate emissions at its Kamloops, B.C., pulp mill. The capital investment of $57.6 million will be entirely funded by credits received from the Government of Canada’s Pulp and Paper Green Transformation Program.

“The funding for these projects, together with support from BC Hydro’s Integrated Power Offer for industrial customers, was instrumental for Domtar in moving forward with these important improvements,” said Eric Ashby, general manager of the Domtar Kamloops mill.

The first phase of work related to these projects is expected to begin in late May 2010, during the mill’s annual maintenance shutdown. The air emissions improvement plan proposes two mill-level stacks for wood-burning power boilers.

Domtar was allocated credits totaling $143 million dollars under the Pulp and Paper Green Transformation Program. It owns and operates four pulp and paper mills in Canada, all eligible for this program.

PORT MELLON, B.C. — The Howe Sound Pulp and Paper mill in Port Mellon, B.C., will receive funding under the Pulp and Paper Green Transformation Program (PPGTP) for its evaporator capacity increase project. This project will allow the mill to improve its environmental performance by increasing its energy efficiency and production of renewable energy. The mill plans to invest in a series of upgrades to its evaporator to redirect more steam for the production of electricity and to realize overall efficiencies in the equipment’s operation. By augmenting its renewable energy production, the mill is reducing its reliance on natural gas, which will lead to a reduction in greenhouse gas emissions. The upgrades are also expected to produce an excess of 8,200 megawatt-hours of electrical power — enough energy to power 800 homes a year — which the mill plans to sell to BC Hydro.

“The future of Howe Sound, and the Canadian pulp and paper industry, is closely tied to improved energy efficiency and increased renewable energy production,” said Mac Palmiere, president and CEO of Howe Sound Pulp and Paper.

“The Pulp and Paper Green Transformation Program provides us with a golden opportunity to make investments that will help improve our performance in both of these key areas.”

Thurso, from page 8 plant at the facility to produce green electricity positioned the company to benefit from these grants.

The mill won’t be making an immediate switch from NBHK production to dissolving pulp, however. Thurso will continue to churn out kraft pulp for another full year before producing its new product line starting in June 2011.

Once the transition is over, the mill will produce 200,000 tonnes of air-dried product annually. The company plans to capitalize on bolstered demand for NBHK first. Wasilenkoff expects the restructuring to be a smooth process, however, as it requires very little in the way of retrofitting. Much of the equip42

PULP & PAPER CANADA May/June 2010

ment currently in the mill will be suitable for the production of dissolving pulp as it shares much in common with the process of manufacturing NBHK. With a secure and reasonably priced fibre source (the company has a 50% Crown allocation), a ready-made labour force, and strong market fundamentals, Fortress appears poised for success. Coupled with Chad Wasilenkoff’s unstoppable “can-do” attitude, Canada’s pulp and paper sector may have a new market leader, and mentor, for the future. PPC * After price adjustments, Wasilenkoff notes, the final price paid for the Thurso facility may be in the order of $900,000.

In the March/April 2010 issue, it was incorrectly reported that an air emissions improvement project at Domtar’s Kamloops mill would include “haystacks”. In fact, the air emissions improvement plan proposes milllevel stacks for wood-burning power boilers. The high-stack will remain in use and most of the fine particulate will continue to be directed to the high stack.

NS Power and NewPage seek approval for biomass cogen project

Nova Scotia Power and NewPage Port Hawkesbury are once again seeking approval from the provincial utility regulator for a proposed biomass cogeneration facility. The power company recently announced an agreement with NewPage Port Hawkesbury Corp. to develop a new 60 MW biomass co-generation facility.

The development entails an investment of $200 million from Nova Scotia Power, which includes $93 million in construction costs for new facilities, $80 million to purchase assets from NewPage, and other related costs. NewPage will be responsible for the construction and operation of the co-generation facility and be completely responsible for fuel supply.

The project remains subject to regulatory approval from the Nova Scotia Utility and Review Board and is targeting an in-service date of late 2012.

The two partners have previously tried for Utility and Review Board approval for this power deal, but the board said last summer it lacked authority to approve such an electricity purchase plan in advance.

NewPage and Nova Scotia Power have stated that only “stem wood” will be used in the project’s biomass energy generation. Tree stumps, tops and branches will not be removed from the forest floor as they are necessary in restoring nutrients in the soil. The NewPage Port Hawkesbury mill, located in Point Tupper, Richmond County, has the capacity to produce 190,000 tonnes of newsprint and 360,000 tonnes of supercalendered paper.

The company’s Woodlands Unit currently manages approximately 600,000 hectares of Crown land and an additional 20,020 hectares of company-owned land. pulpandpapercanada.com

00604_281008

Inspiring great effects.

Every time.

In Eka you’ll find a global partner with expertise close to your operations. In the form of Dan Pernsteiner in North America and Martin Chen in China, for example.

Intimately acquainted with papermaking, Dan and Martin spend most of their time working with mill operators. Both of them admit to the rush when solutions exceed expectations (including their own) – and that’s why they’re dedicated to Compozil.

As Dan says, Compozil is a blend of experience, know-how and business sense. (His High-Speed Video Audit can show all the details, if you like.)

Proof can be found at Gold East, where Martin has worked closely with the mill on the application of Compozil Fx. Today, Gold East’s huge, advanced machines are running even faster and even better.

Put simply, Compozil is how we make papermaking everywhere smoother.

Inspiring paper all over the world is our inspiration. Meet us at eka.com.

Eka Chemicals AB, SE-445 80 Bohus, Sweden. Tel: +46 31 58 70 00 Eka Chemicals Inc. Marietta, Georgia, USA. Tel: +1 800 241 3900 Eka Chemicals (Thailand) Ltd. Bangkok, Thailand. Tel: +66 2 712 72 93 www.eka.com

TECHNOLOGY NEWS

Datalogger Tailored to Forest Operations Forestry managers in every region share a common need: to obtain accurate information on machine productivity so they can improve the economics of their operations. In response to this need, FPInnovations has developed a secondgeneration datalogger, the MultiDAT. This electronic device can be installed on any machine or vehicle involved in off-road operations.

MultiDAT can record machine functions, movement, location, and even operator comments.

When linked with up to four sensors, provided by the user, the MultiDAT can record the operation of the related functions. This permits analysis of the duration of a function’s activation, the number of activations, and measurement of a frequency at specific intervals (e.g., monitoring a speed sensor).

MultiDAT comes equipped with an adjustable internal motion sensor that detects movement of the machine, but not vibrations of the motor. In many cases, you

can quickly determine the true operating time for a machine without requiring any additional sensors.

Users can add a GPS option to collect positional data and determine the areas harvested or treated. Geofencing capabilities are also available. The data can be exported for analysis using ArcView or compatible software.

The operator can enter codes on the MultiDAT keypad that describe the work in progress, the reason for machine downtime, and the current machine operator. You can customize the codes for your operation and determine the hours the operator worked, the type of work done by the machine, and the reasons for any work stoppages.

Even the report format is configurable.

Using the MultiDAT software, select which information to compile and how to compile it (e.g., daily, weekly, by operator, etc.) using your personal computer.

FPInnovations, 514-694-4631, ext. 314, www.fpinnovations.ca

Metso’s High Speed All-in-One Tissue Sensor Goes Non-Nuclear After extensive field testing in tissue mills, Metso is now delivering a new all-inone sensor which measures tissue fibre weight and moisture simultaneously in the PaperIQ Select quality control system. The new sensor, called IQFiber, measures fibre weight and moisture on the same spot of paper using a multi-channel infrared detector. The need for a traditional basis weight sensor with a nuclear source has been eliminated. Therefore, the time and costs involved in nuclear safety training, nuclear licenses and specialized service and safety requirements have been eliminated.

IQFiber is installed in numerous tissue mills using virgin pulp or 100% recycled furnish. Users of the IQFiber sensor report lower maintenance and cleaning requirements, leading to increased productivity. Also, with more precise control over dry fibre weight, tissue makers have been able to reduce target sheet weight at the same quality, thereby saving valuable fibre furnish.

The speed of response and signal to noise ratio of the IQFiber measurement are significantly better than traditional nuclear sensors, making it most appropriate for the detection of transient or cyclical variations

and allowing more precise control.

This high speed measurement analysis adds a significant troubleshooting capability to the system, making it possible to perform detailed online variability studies and to make process improvements.

Metso, 514-335-5426 www.metso.com

Andritz Helps SCA Convert to Renewable Fuels International Technology Group Andritz has been awarded two orders by SCA of Sweden. The first is to supply a new lime kiln with fuel handling and white liquor filtration equipment to SCA’s Östrand pulp mill. The delivery is part of SCA’s BioLoop project, in which the mill will change its systems from oil to renewable fuels in order to enhance the general environmental friendliness of the mill.

The new lime kiln will be fueled by wood dust, which will also lead to lower chemical and maintenance costs for the mill. The scope of supply also includes wood dust burners for the existing

44

PULP & PAPER CANADA May/June 2010

power boiler. The white liquor filter is scheduled to be started up in spring 2011, and the lime kiln in autumn 2011.

For the SCA Packaging pulp mill in Obbola, Andritz Pulp & Paper will supply green liquor and dregs handling equipment, including a LimeGreen™ filter, a LimeFree™ centrifuge, and a lime mud filtration system. This delivery includes process electrification and instrumentation, as well as modification of the existing control system for the new process equipment. Start-up is scheduled for spring 2011.

Andritz 514-631-7700, www.andritz.com pulpandpapercanada.com

TECHNOLOGY NEWS

Professional Connections Equipment

VINCENT CORP. SCREW PRESS Clarifier Sludge Knots & Shives Screen Rejects Stock Thickening Recycle Rejects Black Liquor

FREE ON-SITE DEMOS www.vincentcorp.com (813) 248-2650 Fax: (813) 247-7557

Careers PulP & PaPer Jobs Freeman Staffing, Inc. specializes in the placement of engineers (all disciplines), production type supervisors, managers, mill and/or plant managers and corporate executives in the pulp & paper industry, North America-wide. For specific current job searches call us or contact our web site. All resumes are treated with complete confidentiality.

Freeman Staffing, Inc.

(800) 221-9629 or FAX (360) 653-8271 email: markp@freemanstaffing.com

web site: www.freemanstaffing.com

Consultants

• • • • • • • • • • • • • • • • • • • • • • • • • • • • • •

• • • • • • • • • • • • • • • • • • • • • • • • • • • • • •

BOILERS SELL • RENT • LEASE

24 / 7 EMERGENCY SERVICE

IMMEDIATE DELIVERY

CALL: 800-704-2002 10HP TO 250,000#/hr

250,000#/hr Nebraska 750 psig 750OTTF 150,000#/hr Nebraska 1025 psig 900OTTF 150,000#/hr Nebraska 750 psig 750OTTF 150,000#/hr Nebraska 350 psig 115,000#/hr Nebraska 350 psig 80,000#/hr Nebraska 750 psig 80,000#/hr Erie City 2000 psig 800OTTF 75,000#/hr Nebraska 350 psig 70,000#/hr Nebraska 750 psig 750OTTF 60,000#/hr Nebraska 350 psig 40,000#/hr Nebraska 350 psig 20,000#/hr Erie City 200 psig 10-1000HP Firetube 15-600 psig ALL PRESSURE AND TEMPERATURE COMBINATIONS SUPERHEATED AND SATURATED

RENTAL FLEET OF MOBILE TRAILER-MOUNTED BOILERS 75,000#/hr.

75,000#/hr.

60,000#/hr.

50,000#/hr.

40,000#/hr.

30,000#/hr.

75-300HP

Nebraska Optimus Nebraska Nebraska Nebraska Nebraska Firetube

350 psig 750 psig 350 psig 500 psig 350 psig 350 psig 15-600 psig

750°TTF

ALL BOILERS ARE COMBINATION GAS/OIL

ENGINEERING • START-UP FULL LINE OF BOILER AUXILIARY SUPPORT EQUIPMENT. Electric Generators: 50KW-30,000KW

WEB SITE: www.wabashpower.com 847-541-5600 • FAX: 847-541-1279 E-mail: info@wabashpower.com

wabash

POWER EQUIPMENT CO.

444 Carpenter Avenue, Wheeling, IL 60090

Consultants Engineering services for the pulp and paper industry

Morbark Adds Compact Whole Tree Chipper to Line-up

Aimed at the in-woods chipping market, the Morbark 25/36 Whole Tree Chipper is an ideal unit for those processing moderate volumes. Equipped with a 25” x 22” infeed opening and horsepower options ranging from 325 – 400 HP, this chipper is compact but is still highly efficient and productive.

The Morbark 25/36 uses the proven design and technologies of its big brothers, the Morbark 30/36 and 40/36 models, but with a more compact profile.

“Providing chips to the biomass and fuel markets is gaining popularity every day,” states Patrick Andres, sales manager for the Western United States. “The 25/36 will allow operators to enter the biomass fuel market with a smaller capital investment.”

Standard equipment on the Morbark 25/36 Whole Tree Chipper includes the Morbark Integrated Control System, a diagnostic system that monitors hydraulic pressures, temperatures, clutch systems and engine efficiency while automatically adjusting to maximize performance.

Morbark Inc., 989-866-2381, www.morbark.com pulpandpapercanada.com

Telephone 416. 391. 2322 E-mail mail@dickeng.com Web site www.dickeng.com

Global Know-how and Local Service for the Forest Industry Pöyry (Montreal) Inc. Montreal, QC 514 341 3221

Pöyry Forest Industry Consulting Inc. Tarrytown, NY Montreal, QC 914 332 4000 514 845 8715

Pöyry (Vancouver) Inc. Vancouver, BC 604 689 0344

Pöyry (Appleton) LLC Appleton, WI 920 954 2000

Engineering balanced sustainability for a complex world. www.poyry.ca

May/June 2010 PULP & PAPER CANADA

45

TECHNOLOGY NEWS

Abrasion-resistant Pipe Exhibits Dual Personality When abrasive material is transported through piping, either as pumped slurry or via pneumatic conveyance, the effect on the inner surface is devastating. The abrasive material quickly erodes the pipe from the inside out.

For industries that regularly transport abrasive material, such as mining, power generation, pulp and paper, food, wastewater, cement, and steel industries, mild steel piping systems are simply not tough enough to stand up to the beating for more than a couple of years.

One type of pipe delivers abrasion resistance without brittleness: an induction hardened pipe with an abrasion resistant inner surface that tapers to a strong, yet ductile outer surface.

The induction-hardened Ultra 600 pipe from Ultra Tech has an inner surface of 600 BHN, and tapers to a 250 BHN outer surface that is ductile enough to accommodate normal handling during shipment, installation and maintenance.

Because the outer surface behaves like mild steel, the product can be cut and welded with proper procedure in the field, configured into a variety of fittings, and can accept the standard end options of flanges, weld rings and couplings.

Ultra Tech Pipe, 800-626-8243, www.ultratechpipe.com

Hose Pump Reduces Maintenance When Pumping Abrasive Paper Coatings Watson-Marlow’s durable Bredel SPX hose pumps reduce maintenance downtime and increase profitable production when pumping abrasive paper coatings. Using no valves, seals or rotors in the product stream, the SPX can run dry and withstand pressures to 232 psi. Advanced hose technology enables repeatable continuous 1% metering accuracy of hard-to-handle viscous, corrosive, or particle-laden fluids at flows up to 400 gpm.

The Bredel SPX hose pump allows for uninterrupted paper production by eliminating the need for seals or valves that can clog, leak or corrode to create unwanted maintenance costs and production downtime. With the SPX design, pumped material only comes into contact with the hose, leading to longer pump life. Additionally, hose replacement is quick and easy due to a self-loading design.

Unlike other pump types, the SPX pump life is unaffected by the highly abrasive nature of lime slurries, corrosive fluids and other viscous materials. The combination of these features makes the SPX an enduring solution for challenging pulp and paper applications such as coatings, green liquor and black liquor soap, alum, latex, glue, acids and alkalis, polymer, ink, kaolin, lime slurry, and titanium dioxide Watson-Marlow, 800-282-8823, www.watson-marlow.com

West Fraser Timber Selects Carbonetworks to Provide Integrated Carbon and Energy Performance Management Solution After a comprehensive evaluation, West Fraser Timber Co. Ltd. has selected Carbonetworks™, to help it manage and reduce its carbon footprint. Carbonetworks is a provider of performance management software for energy, greenhouse gas (GHG), and sustainability solutions.

West Fraser’s Canadian facilities have already reduced emissions by more than 28% since 2000, clearly demonstrating their commitment to environmental stewardship.

To date, West Fraser has used manual processes and spreadsheets to manage energy data, GHG emissions and compliance reporting. In order to mitigate risk, time, and cost, West Fraser was looking for a technology solution to help automate these processes. The Carbonetworks solution enables West Fraser to efficiently manage and reduce its energy usage and carbon footprint, transforming energy, GHG, and sustainability initiatives into measurable business results.

“West Fraser manages energy and carbon as a business, which is in alignment with the Carbonetworks philosophy. Carbonetworks

46

PULP & PAPER CANADA May/June 2010

stood out from competitors on multiple levels, including the capability to set and monitor reduction goals, model project paybacks and track energy/GHG reduction initiatives across multiple facilities from one central vantage point,” said Veikko Paivinen, financial manager, energy and carbon.

“We are thrilled to partner with an industry leader such as West Fraser,” said Michael Meehan, CEO and president of Carbonetworks. “West Fraser has adopted the full cycle of carbon and energy management from basic inventory measurements to compliance reporting to carbon trading – all in the context of financial returns and business value – which will be made more scalable and predictable with the help of Carbonetworks technology.”

West Fraser is an integrated wood products company producing lumber, wood chips, LVL, MDF, plywood, pulp and newsprint. The company has operations in western Canada and the southern United States.

Carbonetworks, 250-298-4200, www.carbonetworks.com pulpandpapercanada.com

www.paptac.ca Call for papers

ANNUAL MEETING 2011

The Association’s 97th Annual Meeting will be held in Montreal early February 2011 and is the flagship event for the Canadian pulp and paper industry. Paper submissions are requested in the areas of bleaching, papermaking, pulping, process control, research, engineering, environment, recycling, energy cost savings, business, and other emerging industry topics.

At the time of submission, authors are requested to designate the category under which they would want their paper to be evaluated. If more than one category is designated, the submission will go to the first program committee that accepts it. Submissions are welcome in English and French.

The deadline for abstract submissions is September 10, 2010.

For further information, please contact Greg Hay at ghay@paptac.ca or 514.392.6964.

INTERNATIONAL MECHANICAL PULPING CONFERENCE 2011

Call for papers

The next edition of the IMPC will be hosted in China in June 2011, and is co‐sponsored by PAPTAC, TAPPI (USA), SPCI (Sweden), and PI (Finland).

Papers are sought on all aspects of mechanical pulping – energy use, pulp brightening, fibre characteristics, pulp quality and paper properties, and will take place in one of the most active areas in this field.

Those wishing to present a paper or poster, should submit their abstract to Greg Hay at ghay@paptac.ca by September 17, 2010.

Information on registration fees, registration procedures, hotels, program, social functions and other conference related logistics will be forthcoming shortly. Visit www.paptac.ca periodically for updates.

Contact: C Lato (clato@paptac.ca / 514.392.6969) or G Hay (ghay@paptac.ca / 514.392.6964)

THEORY & PRACTICE OF PAPERMAKING TRAINING WEBINARS

TPPM

Mill equipment and processes have evolved to become faster, more efficient, and more consistent.

Do not rely on outdated manuals as the primary means to transfer knowledge. Plan to register for the upcoming series of Papermaking webinars aimed at new or inexperienced workers in this sector, or those wishing for a refresher, on the overview of the paper machine and its operations at both the wet and dry ends and an understanding of the fundamental principles.

Call Carmie Lato at 514.392.6969 or email clato@paptac.ca for complete details.

Virgin fiber. Reclaimed fiber. Moral fiber.

It’s how the best paper is made. With strength of character and firmness of purpose. For 60 years, Buckman has provided just that to the paper industry. We’ve grown into a global success by aligning our business model with our customers’ specific needs. With Buckman, you get continuity, commitment, and innovation. You get professionals who see your success as a measure of their own.

Find out how we can help your mill save time, energy, and money.

Visit buckman.com or call 877-BUCKMAN.

©2009 Buckman Laboratories International, Inc.