MARCH 1998

PyrolysisNetwork.

SuubergDo cellulose pyrolysis kineticsdepend upon heating rate?on page 4

Di Blasi looks at Pyrolysis Modellingon page 16

RadleinConcluding part to Chemicals and Materials from Bio-oil on page 12

ISSUE 5

Comments and contributions are most welcome on any aspect of the contents.Please contact your country representative for further details or send material to Claire Humphreys.

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TheFuture.

With effect fromJanuary 1998,the EC SponsoredPyrolysis Networkamalgamated withthe new IEABioenergy PyrolysisActivity and is nowto be known as PyNe.

This Newsletter will be maintained as abiannual publicationand will report on awide range of topicaland news items. We are pleased towelcome Canada andthe USA and are sure that they willmake a valuablecontribution to the activities of the Network as well as learningabout the many European projects.

IEA Bioenergy+ =PyNe

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The Future

Conference & Meeting Reports

Do Cellulose Pyrolysis KineticsDepend Upon Heating Rate – Part 1

Compact Power

Catalytic Upgrading of Biomass – Derived Oils

University of Zaragoza

THERMIE

JOULE

INETI

Chemicals & Materials from Bio-oil – Part 2

Exchange Visits

Pyrolysis Modelling

Co-Combustion of Biomasson a Fluid Bed Pyrolysis Unit

Solar Energy & Biomass Pyrolysis

News from North America

Book Reviews

Diary of Events

PyNe Membership

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Co-ordinatorTony Bridgwater

AdministratorClaire Humphreys

Bio-Energy Research Group,Aston University, Birmingham B4 7ET

Tel +44 (0)121 359 3611Fax +44 (0)121 359 6814

email a.v.bridgwater@aston.ac.ukc.l.humphreys@aston.ac.uk

http://www.ceac.aston.ac.uk/PyNE/

Workshop– Residues for Energy ProductionThis Workshop took place in Coimbra, Portugal, from 24-26 November 1997with the aim of promoting a dialogue between industrial companies andresearch institutions for the energetic valorisation of biomass.This had the objective to not only to show the strategic vectors of energydiversification, but also to clearly identify business opportunities.

Conference & meeting reports.

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The programme was divided into four main areas:

1. Harvesting, processing and conditioningof forest residues

2. Energetic valorisation of forest residues

3. Energetic valorisation of other residues

4. Energy conversion technologies

The following oral presentationswere made and discussed withthe audience:

● Biomass flux analysis – CBE, Portugal

● Finnish technology for wood fuel andintegrated wood raw materialprocurement – VTT, Finland

● Present state and perspectives of theutilisation of forest and wood derivedindustries for heat and power productionin Spain – CIEMAT, Spain

● Systems for forest fuel handling inSweden – Forest Research Instituteof Sweden, Sweden

● Truck hauling in integrated harvestingsystems – Swedish University ofAgriculture Sciences, Sweden

● Fruit tree pruning machine as apotential producer of residueswith energy value and in controlof bushland – Evora University, Portugal

● Energy valorisation of biomassresidues in fluidised bedcombustion systems – INETI, Portugal

● Finnish technology for burningbiomass fuels – VTT, Finland

● Project implementation of athermoelectric power plant usingforest residues – EDP Group, Portugal

● Biomass: source of renewableenergy – Olsson, Portugal

● BMH Wood Technology – Oy, Finland

● Integrated waste management; wasteas a resource in the energy and materialsystems – NUTEK, Sweden

● Energy from waste in Austria:development, status and problems – University of Vienna, Austria

● Italian situation about Wastefor Energy – ITABIA, Italy

● Energy production from Lisbon municipalsolid waste – PROET, Portugal

● The Danish Waste for Energy Plansand the future focus on industrialwaste – DK Teknik, Denmark

● The future of biomass in Europe:how can we make joint progressand where are the barriers in thisnew bio-energy sector? – SUC, Denmark

It was very useful for Portugal, becauseit allowed industrial companies to obtainimportant and useful information fromPortuguese and abroad research institutesabout the possibilities of getting energyfrom biomass. This workshop also enabledthe establishment of important contactsand participants to share information.

Conference ProceedingsProceedings can be obtained from:CBE – Centro da Biomassa para a Energia(Biomass Centre for Energy),

Tel: +351 39 53 436

Fax: +351 39 52 452

Email: cbe@cbe.mailpac.pt

Compiled by Filomena Pinto, INETI, Portugal and Cordner Peacocke, Aston University, UK

The new Pyrolysis Network sponsored by the EC FAIR Programme and IEABioenergy had its inaugural meeting inSalzburg, Austria. In addition to welcomingthe new representatives from Canada and theUSA, the group also welcomed the newEC FAIR Scientific Officer – Ann Segerborg-Fick.

PyNe Kick-off Meeting,Salzburg, March 1998

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Third BiomassConference of the Americas, Montreal, Quebec, Canada,24-29 August 1997

3rd International ManagementConference – Waste to EnergyThe primary objectives of this conference, whichwas held in Copenhagen, Denmark, on the 4 & 5December 1997, were:

● Assessing the future of European thermal waste treatment in a global, environmental and socio-economic context

● Benefiting from an update on political choices and strategic business issues for the waste to energy markets

● Challenging management actions versus new regulations

● Exploring new technological improvements and scientific discoveries that might result in new opportunities for the growing waste to energy markets

● Optimising the efficiency of waste power plant and reducing costs.

Oral presentations were given under the following themes:

● The Regulatory Framework

● Incineration and the Public Opinion on theEnvironment Impact. What do practical cases fromday to day experiences teach us?

● Alternative Energy Production. Thermal Treatmentand Waste to Energy

● Economics and Management Strategies.

The conference included an exhibition ofproducts and services.

This was the third in a series of conferences,which alternates with the EU Energy fromBiomass Conference and is held everytwo years. The conference was attendedby over 500 people representing the wideand diverse interests in biomass utilisation.Pyrolysis was fairly well represented and 12 papers were presented for theproceedings with 3 posters for theinteractive cluster session.

Tours

During the course of the conference,there were three scheduled tours ofinterest to pyrolysis:

● Burlington Gasifier, Vermont

● Pyrovac Institute, Quebec

● Forintek Canada Corporation, Quebec

Vermont Gasifier Tour

The US DoE has funded a 7.5 t/h fluid bedgasifier, located at Burlington, Vermont. This twin fluid bed wood gasifier operatesin a similar mode to a high temperaturepyrolysis reactor and hence is of interestfor technical reasons. The char product isburned in a separate reactor and is usedto heat the sand which is returned to thepyrolysis reactor. The aim of the project isto operate a 15 MWe gas turbine on theproduct gas after cleaning. The facility wasstill in the construction phase in August,with planned start up in November 1997.

Pyrovac Institute Tour

The Pyrovac technology was featured in the3rd issue of the PyNE newsletter. The tour ofthe Pyrovac Institute included the 75 kg/hvacuum pyrolysis plant, which was operatingfor the visit, giving the tour delegates theopportunity to see the production of vacuumpyrolysis liquids. Professor Christian Royhosted an excellent and informative tourof their facilities.

Forintek Canada Corporation Tour

Forintek is a leading developer of woodand wood-related products, focusing onsawn limber and composite products.The Forintek offices are in close proximityto the Pyrovac institute and a useful insightinto the preparation of wood laminatesand composite materials was obtained.

Conference Proceedings

A two-volume set is available:Title: Making a business from biomass

in Energy, Environment,Chemicals, Fibres and Materials –3rd Biomass Conference ofthe Americas.

Editors: Overend, R.P. and Chornet, E.

Publisher: Elsevier Science Ltd.

Year: 1997

ISBN: 0080429963

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part 1Mass transfermay play a role in determiningcellulose pyrolysis kineticsBy Eric M. Suuberg, Brown University, USA

Do cellulose pyrolysis kinetics depend upon heating rate?

As worldwide interestin harnessing the energypotential of biomassfuels increases, so toodoes the interest inimproving ourunderstanding of thecomplicated processesinvolved in theirthermal conversion.Development ofadvanced processconcepts is greatlyaided by detailedquantitative modelswhich require such basicunderstanding. Thefocus in this article is

on the key processing step which is commonto all these conversion strategies – pyrolysis.

A Typical Path into the Morassof Cellulose Pyrolysis Kinetics

Upon initial examination of the literature inthe field, it appears as though there alreadyexists an almost overwhelming wealth ofdata; the need to add just a few moreexperimental results is not at all clear. There have been numerous studies of productcomposition, pyrolysis kinetics andmechanism and some studies combineseveral of these aspects. There do, however,tend to be many more of what may betermed “basic” studies on cellulose pyrolysisthan on whole biomass pyrolysis. This iseasily understood, in terms the difficulty ofextracting sound scientific understandingfrom chemically very complicated systems.

Several years ago, our laboratory wasengaged in a study of fire phenomenain bulk cellulosic solids, with a primaryfocus on the role of transport processes inshaping the slate of products from cellulosepyrolysis. A mathematical model of bulksample pyrolysis was developed, in whichheat transfer control was the central feature,since accompanying experiments clearlyindicated this character. The overall modelrequired a kinetic sub-model to describepyrolysis in some non-heat transfer control regimes. The selection of the appropriate kineticmodel was, however, difficult since differentpublished kinetic models offered widelydiffering predictions of the extent ofpyrolysis in the interior of the sample.This prompted us to more thoroughlyreview the literature and to conduct ourown kinetic experiments on the particularmaterial of interest in our study, WhatmanCF-11 cellulose powder (a 99% a-celluloseof very low ash content).

Which Kinetic Constants Are “Correct”?

The review1 of global mass loss kineticswhich we presented in 1995 was immediatelysomewhat controversial when published. In it, we observed that the literature can beinterpreted to suggest that higher heatingrate data suggest lower apparent activationenergies, and lower heating rate data higherapparent activation energies for the mainmass-loss step of pyrolysis. A summary ofthe reported kinetics is shown as Figure 1.

Is the Discrepancy Due to HeatTransfer Limitations?

It appeared, on the basis of the experimentsthat we conducted ourselves, that thedifference in kinetics was actually moreattributable to the temperature at whichthe decomposition took place, more thanthe heating rate per se. It was also clearthat, as had been observed by many othersbefore us, the modelling of the mass lossprocess with a single-step reaction wasquite a crude approximation. For one thing, a clean determination of order was impossible.

0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.21000/T [K]

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Figure 1: A comparison of published data on mass loss rates

for cellulose pyrolysis. The solid line represents a mean from

many studies conducted at heating rates less than 10 K/min,

and the dashed line represents a mean from many studies at

heating rates above this value. The activation energies are

around 140 kJ/mol for the higher heating rate studies and

200 kJ/mol for the lower heating rate studies1.

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Figure 2: The enthalpy of pyrolysis of Whatman CF-11

cellulose, as a function of mass loss from the sample, and its

heating rate. The pyrolysis process is always initially

endothermic, and almost linear in mass loss. At high heating

rates, this character is maintained throughout the process.

At low heating rates, the well-known exothermic char forming

processes begin at some point to compete with the basic

endothermic nature of the process, and drive it back towards

thermoneutrality3. There is, however, no evidence of

thermodynamically different pathways being followed at high

and low heating rates, during the initial stages of pyrolysis.

This alone does not assure that a change of mechanism

does not occur, but there is also no other evidence

to suggest such a change in mechanism

with heating rate.

We were aware of the concerns that had beenexpressed for some time by Antal andcoworkers2 regarding the possibility of heattransfer limitations could cloud theinterpretation of kinetics. This seemedunlikely in our own work, in which athermocouple was placed into direct contactwith the samples. Our own heat transfercalculations appeared to rule out alimitation1. It is moreover difficult tojustify why, in the presence of heat transferlimitations, a relatively constant activationenergy of near 140 kJ/mol would emerge,and apply over a very wide range ofheating rates, up to 1000 K/s, as seemedto be implied in the literature. Normally,when heat transfer limitations cloud theinterpretation of data, it is difficult tofind a good constant value of activationenergy from the experiments in question.

Evidence in Favor ofTransport Limitations

The above review was followed by a secondarticle in which we outlined the results ofour examination of pyrolysis kinetics usingdifferential scanning calorimetry3. In thatwork, we could see no evidence of a majorshift in the thermal character of the pyrolysisprocess with heating rate. Some of theevidence is presented in Figure 2, showingthe thermal “trajectory” of pyrolysis as afunction of mass loss. It would be expectedthat a major shift in the process would beindicated by a change in thermal trajectory.Such changes are seen, but only indicatethe onset of the exothermic retrogradereactions, rather late during pyrolysis.The main tar-evolving part of the processis very similar, consistent with reportssuggesting that the tars of high and lowheating rate pyrolysis are not much different,

provided that they are quickly quenched. This evidence strongly suggested to us thatthe basic chemical pathway of pyrolysis didnot, in fact, change with heating rate, untilthe exothermic char-formation processesbegan to occur. This meant that there should be no shift in the activation energyof the processes controlling the main periodof mass loss, and yet, such a shift wasobserved. The inescapable conclusionwas that the shift in activation energy waslikely to indicate the onset of a transportlimitation. Thus we felt that we couldnot invoke heat transfer limitations forthe reasons cited above, and yet hadto invoke some transport limitations.The resolution of this apparent paradoxcame in a hypothesized role of masstransport limitations4. These will bediscussed in Part 2 of this presentation.

References1. Ivan Milosavljevic and Eric M. Suuberg, “Cellulose

Thermal Decomposition Kinetics: Global Mass LossKinetics”, Ind. Eng. Chem. Res., 1995, 34, 1081-1091.

2. Michael J. Antal, Jr., H. L. Friedman, and F. E. Rogers,“Kinetics of Cellulose Pyrolysis in Nitrogen and

Steam”, Combustion Science and Technology,1980, 21, 141-152.

3. Ivan Milosavljevic, Vahur Oja, and Eric M. Suuberg,“Thermal Effects in Cellulose Pyrolysis: Relationshipto Char Formation Processes”, Ind. Eng. Chem. Res.,

1996, 35, 653-662.4. Vahur Oja and Eric M. Suuberg, “Development

of a Nonisothermal Knudsen Effusion Method andApplication to PAH and Cellulose Tar Vapor Pressure

Measurement”, Analytical Chemistry, 1997,69, 4619-4626.

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Compact Power, a UK basedcompany, has developed a combinedpyrolysis and gasification processwhich provides a new and economicsolution for the disposal of waste.

Traditionally domestic and commercialwastes have been disposed of by buryingin landfill sites but this is becoming anexpensive, difficult and, in some instances,unacceptable practice. Incineration has beenanother option but there is a growing publicresistance to such plants due to their size,fears of pollution from their flue gasesand the impact they have on localneighbourhoods from lorry traffic, noiseand loss of visual amenity.

The Compact Power process offers modularplant capable of treating a wide variety ofwastes including municipal solid waste(MSW), clinical waste, animal and bio-masswastes, sewage sludge cake, industrial wastesand tyres. The plants are identified by thenumber of pyrolysis tubes employed rangingfrom an ‘MT2’ unit with two tubes capable oftreating 6,000 tpa of clinical waste to an‘MT8’ with eight tubes capable of treating30,000 tpa of MSW. Combinations of theseunits allow the plants to be sized to matchthe waste available with the advantage thatthey can be readily up-sized or down-sizedas disposal and recycling practices change.

The schematic of the process (Figure 1),shows the various stages of this thermo-chemical conversion technology. The wasteis introduced into the pyrolysis chamberthrough tubes which form the basic unitof the system. Using the Compact Powerprocess of compacted fuel ‘slugs’, it ispossible to operate the plant on acontinuous basis which makes it idealfor CHP and other applications where highgrade heat is required without interruption(such as district heating schemes).

The fuel material is pyrolysed at about700°C to produce hydrocarbon gases whichare taken directly into a thermal oxidationreactor operating at 1250°C. This preventsthe cooling of the gases and the opportunityfor noxious by-products to be formed.The carbon char in the solid residue is thengasified at 1000°C to produce a carbonmonoxide and hydrogen off-gas leavinga final ash which is inert and non-leachableand suitable for a number of applicationsincluding the production of ‘breeze’ building blocks.

The high temperature gases are oxidisedin the thermal reactor for at least twoseconds which at 1250°C is extreme enough to ensure that any pollutantgases and particulates are totally destroyed.The exhaust gases are ducted over thepyrolysis tubes to provide the energy tomake the process self-sustaining. From here, the gases are cooled by passing themthrough a steam boiler designed to reducethe temperature rapidly and thus preventthe reformation of any dioxins or furans.

The exhaust gases are subjected to afinal ‘polish’ by a dry remediation processbefore being exhausted through a lowheight chimney sized so as to ensure thatthe gaseous emission satisfy the highestenvironmental standards.

Modular design means that the capital costis low and the multiple tube design provideshigh availability with low operating andmaintenance costs. Compact Power estimatethat the plants will cost about 60% of state-of-the-art conventional incinerationplant of the same capacity.

Compact Power has successfully completedtrials on a 400 kg/hr full sized pilot plantand has now commenced work on thebuilding of a 6,000 tpa MSW and clinical‘Energy from Waste’ plant to be sited atAvonmouth, near Bristol, UK.

Compact PowerBy John Acton, Compact Power, UK

Figure 1: Compact Power – MSW Pyrolyser Plant

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Catalytic upgrading ofbiomass-derived oilsBy Narendra Bakhshi, Professor Emeritus, University of Saskatchewan, Canada

Experimental set up for catalytic conversion ofbiomass-derived oils

Experimental set up for Steamgasification of biomass chars

Further information onany of these projects can

be obtained from:

Narendra Bakhshi,Professor Emritus CCREL

Department ofChemical Engineering

University of Saskatchewan Saskatoon, SK S7N 5C9

CANADA

Tel: +1-306-966-4763Fax: +1-306-966-4777

There are nearly 20,000students in variousdisciplines at theUniversity, almost 2000of whom are graduatestudents. There are about1,100 faculty members.

The upgrading work is beingcarried out in the Catalysis and Chemical Reaction Engineering Laboratoryin the Department of Chemical Engineering.The major focus of the research in thelaboratory is in the following biomass-related areas. Projects 1 and 2 are fundedthrough Bioenergy Research & Development,Alternative Energy Division, CANMET, Ottawa.

Project 1: Characterization and Catalytic Conversion of Biomass-Derived Oils (BDO)

The focus of this work is on the physicaland chemical characterization of biomassderived oil as well as studies on theirstability. Also, various catalysts have beenused to study the upgrading characteristicsof biomass derived oils.

Catalytic upgrading of biomass-derived oilhas been receiving attention as an alternatesource of fuels. The major advantages arethat these fuels are CO2 neutral and containvery low fractions of bonded sulfur andnitrogen. Thus they contribute little tothe greenhouse gases or other regulatedair pollutants.

As the biomass derived oil contains a highoxygen content (around 45 wt %) and lowhydrogen to carbon ratio, it needs upgradingbefore it can be used as regular fuel. Currently, two methods have been used toupgrade these bio-oils. The first method is a typical hydrotreatment process using Co-Mo/A12O3 or Ni-Mo/A12O3 catalysts.

The process requires high pressure operationin the presence of hydrogen, also, coking ofthe catalyst is a major problem.

The second method uses essentially HZSM-5zeolite catalyst for upgrading purposes.The operation is at atmospheric pressureand hydrogen is not required. The productfrom the first process consists of aliphatichydrocarbons whereas the product fromthe second process consists mostly ofaromatic hydrocarbons.

Biomass derived oil upgrading has beencarried out over a variety of catalystsnamely, HZSM-5, HY, mordenite, molecularsieves (SAPOs), silica-alumina, andmixtures of HZSM-5 + silica-alumina.These studies have shown that in somecases, the product slate can be dramaticallyaltered by changing the characteristics(i.e., functionality) of the catalyst.For example, HZSM-5 gave the largesthydrocarbon fraction in the product (mostlyaromatics) amongst all the catalysts studied.

On the other hand, HY and mordenitecatalysts gave a high selectivity forkerosene range hydrocarbons. Products fromSAPOs and pillared clay catalysts consistedof a mixture of aliphatic and aromatichydrocarbons. On the other hand, with amixture of 20 wt % HZSM-5 and 80 wt %silica-alumina catalyst, the productcomposition dramatically changed toalmost all aliphatic hydrocarbons(essentially i-octane which has an octanenumber of 100).

Project 2: Steam Gasification of Biomass Chars

It has been found that chars formed duringthe catalytic upgrading of biomass derivedoils are highly reactive. When gasified withsteam, these chars seem to yield a highcalorific gas. Work is being carried out tostudy the steam gasification of a variety ofother chars as well, such as chars producedduring the pyrolysis of agricultural materials.

Project 3: Production of Fuels and Chemicals from Canola Oil

The thrust of this work is on the conversionof canola oil to a variety of fuels andchemicals, such as C2 – C4 olefins andhydrogen, using a variety of catalysts.

An in depth study on the catalytic upgrading of bio-oils is being carriedout at the University of Saskatchewan, Saskatoon, Canada.The University of Saskatchewan (UofS) was founded in 1907.

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The origins of University of Zaragoza can be traced back to 1474, whenPope Sixtus IV created a “General Study”.

In 1542 this became a university although it was not until 1583 that itactually began to function as such, due mainly to the encouragement andfinancial backing of Pedro Cerbuna, later to become Bishop of Tarazona.

Chemical and Environmental Engineering Department,

University of Zaragoza

The Department ofChemical& Environmental Engineering

By Jesus Arauzo, University of Zaragoza, Spain

Data logging unit

In its beginnings, the University of Zaragozaoffered studies in theology, canon andcivil law, medicine and philosophy. In 1849, theology and canon law wereeliminated, heralding a period of decadence.

Although new faculties and schools werecreated in the second half of the 19thcentury, it was not until the 1970s that

the University of Zaragoza really began togrow with the creation of new centres, the integration of others and its expansioninto the nearby towns of Huesca, Terueland La Almunia de Doña Godina.

Nowadays, the University of Zaragozais made up from 24 centres and thereare 50 departments.

The Chemical and Environmental Engineering Department provides a total of 23 subjects in 5 centres. The staff of the Department consists of 31 faculty teachers, 29 post-graduate and post-doctoral students and 5 laboratory and administrative assistants.

The main research lines that are being developed by the different groups in the Department are:

● Use of sepiolite-type materials as adsorbents of pollutants

● Ecotoxicity of industrial cattle farms

● Characterisation of water pollution in industrial effluents

● Investigation of side effects of the use of chlorinated products in water treatment

● Remediation of soils contaminated by volatile organic compounds

● Development of ceramic membranes by the sol-gel method

● Development of new types of reactors for selective oxidation of hydrocarbons

● Development of mixed oxides used as alternative catalysts in selective hydrogenation reactions

● Development of “in situ” redox fluidized-bed processes

● Study of complex deactivation phenomena and of new regeneration strategies for catalysts

● Safety and risk analysis

● Catalytic pyrolysis and gasification of ligno-cellulosic residues and black liquors

● Down-draft air gasification of wastes

● Use of sewage sludge

● Thermal decomposition of ligno-cellulosic materials and behaviour of materials exposed to fire

● Reduction of NOx emissions in combustion systems

Specifically, the biomass group is studying gasification in down-draft moving bed, reduction of emissions of NOx, combustion and pyrolysis.

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Recent publicationsFast Pyrolysis

Arauzo, J., Radlein, D., Piskorz, J., Scott,D.S., A new catalyst for the catalyticgasification of biomass, Energy & Fuels,8, 1192-1196, (1994)

Arauzo, J., Radlein, D., Piskorz, J., Scott,D.S., Catalytic Pyro-gasification of Biomass.Evaluation of Modified Nickel Catalyst, IECResearch, 36, 1, 67-75, (1997).

Slow Pyrolysis

Bilbao, R., Salvador, M.L., Garcia, P., Arauzo,J., Solid weight loss in the thermaldecomposition of cellulose and pine sawdust,Journal of Analytical and Applied Pyrolysis,24, 257-271, (1993).

Bilbao, R., Salvador, M.L., Arauzo, J.,Influence of the heating rate on thetemperature profiles and on the conversionrate of powdery cellulose and pine sawdust,Journal of Analytical and Applied Pyrolysis,40, 148-159, (1994).

R.Bilbao, J. Arauzo, M.L. Salvador., Kineticsand modelling of gas formation in thethermal decomposition of powdery celluloseand pine sawdust, Ind. Eng. Chem. Res.,34 (3), 786-793, (1995).

Facilities

Specific facilities on pyrolysis include afluidised bed reactor based on the WaterlooFast Pyrolysis Process with a feed rate of10 - 300 g/h; and thermo-gravimetric systemsand fixed bed reactors with capacities frommg up to 2kg.

Studies are being carried out on the thermal decomposition of the ligno-cellulosic components of cellulose, xylan,lignin; agricultural and forestry residues; black liquor, etc. These studies have been carried in:

Black liquor pyrolysis

● Thermo-gravimetric systems and fixed bed reactors. The most significant publications are in this area (see below)

● Fluidised bed reactors. The research work on this area began seven years ago with preliminary experiments and since 1991 has been related to fast catalytic pyrolysis.

Pyrolysis of Biomass

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THERMIE

The activities supported by THERMIE canhelp contribute to, in the immediate andshort term, important policy concerns suchas reduction of environmental hazards –especially CO2 emissions – and increasingthe competitiveness of important actorsin our economies such as Small andMedium-sized Enterprises (SMEs).In addition, technological input as partof a wider implementation of Europeanenergy policy is provided by the effectiveco-ordination between THERMIE and otherRTD programmes as well as EU energyprogrammes like SAVE (policy measuresin energy efficiency); ALTENER (policymeasures in renewables) and SYNERGY(policy measures towards non-EU countries).

The JOULE-THERMIE programme ran until 1997 and had a total budget of 1,030 MECUof which 566 MECU were allocated to theTHERMIE demonstration component of theprogramme for the support of projects andassociated measures. THERMIE focuses on the cost-effective, environmentally-friendly andtargeted demonstration technologies and the promotion of clean and efficient energy technologies.

These consist of Renewable EnergyTechnologies; Rational Use of Energy inIndustry, Buildings and Transport, and aclean and more efficient use of Solid Fuelsand Hydrocarbons. Essentially, THERMIEsupports actions which aim to prove boththe technological and economical viabilityand validity of energy technologies byhighlighting their benefits and by assuringa wider replication and market penetrationboth in EU and global markets.

THERMIE has participated in all the majortechnological breakthroughs in energyin the last decade.

In the sector Energy from Biomass andWaste, emphasis has been given in thefields of large-scale biomass gasificationand utilisation of biomass and wastes withfossil fuels. However, pending the approvalof the 5th Framework programme and theelaboration of its Work-Programme, it isenvisaged to open the future calls to thesubject of flash pyrolysis depending on theprogress achieved in this sector towardsindustrial applications.

JOULE is the R&D component of theNon-Nuclear Energy Programme withinthe Fourth Framework Programme for theEuropean Union RTD activities. It has atotal indicative budget of 450 MECU for theperiod 1994-1998. The bulk of the fundingis absorbed by research projects but thereis also the possibility of funding concertedactions (co-ordination of R&TD activities),and SME’s in particular are supportedby means of exploratory awards andco-operative R&TD projects.

JOULE is divided into five areas, one ofwhich is dedicated to Renewable EnergySources (RES). Biomass and waste, withparticular emphasis on thermochemicalconversion of solid biomass, is part of thisarea. In the successive calls for proposalsthe initial work programme is supplementedto take into account recent developments,ensure continuity with ongoing projectsand focus on the strategic targets.

The presence of industrial partners inthe consortia has increased throughout theframework programme to reach approximately45% in the last call for proposals. Gasification projects have been until now by far the more numerous but the number ofprojects focusing on combustion has increased considerably.

Another six pyrolysis projects will hopefullybe added to the four ongoing projects, thusreaching a total budget in the order of 15MECU in the present Framework Programme.R&D on flash pyrolysis technologies foroptimised bio-oil production and userepresent the bulk of the supported work butnovel concepts (aqueous pyrolysis) are alsopromoted. Much emphasis is put on thedemonstration of utilisation of the oil inboilers and engines by reliable long testingand this is also reflected in the workprogrammes of the projects.

Much progress has been achieved but in viewof the general orientation of the 5thframework programme towards integratedenergy systems, the extent of future supportwould have to be carefully examined in thelight of concrete results and marketconditions allowing an introduction ofpyrolytic oils and by-products to the fuelmarkets in the short to medium term.

JOULE involvement in pyrolysis has beenactive and extensive throughout the lastdecade and has embraced practically allaspects of pyrolytic oil production,optimisation and use; and has included alltechnologies and important European playersin the field, be they universities, researchcentres or equipment manufacturers. Non-European participation in JOULE projects has become more important in the pyrolysissector. JOULE has been present since thebeginning in the construction of all the wellknown European pilot scale facilities and stillremains one of the main supporters of theiroperation and development.

The objectives of THERMIE in demonstrating commercial-scale energytechnology projects and promoting and disseminating information throughassociated measures, still remain as relevant today as they were when theEnergy Demonstration Programmes of DG XVII started in the early 1970s.

JOULEBy Michail Pappadoyannakis, EC, Brussels, Belgium

By Kyriakos Maniatis, EC, Brussels, Belgium

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Some members of the Pyrolysis team

By Filomena Pinto, INETI, Portugal

Nowadays, INETI is a corporate entityendowed with academic, administrativeand financial autonomy. It belongs to theMinistry of Economy and is integrated inthe National Technological System as aTechnological Partner for Industry. INETI iscurrently responsible for a number of R&TDprojects, which include contracts withcompanies, the EU and the Portuguese State.

INETI´s present objective is to contribute,mostly in a multi-disciplinary way, to themodernisation of Portuguese industry so thatindustry can undertake new initiatives andadopt new technologies most suited to itsneeds. INETI also offers direct technologicalsupport and services to companies in areassuch as industrial development contracts,information systems development, PEDIP IIprogramme management, quality, design.

INETI´s scientific and technological activitiesare integrated in coherent programmes andprojects. The priority areas are integratedinto five institutes and three centres:

INETI – national institute of engineering and industrial technology

The Department of Combustion and End-Use Technologies belongs to ITE – Institute of Energy Technology and has developed activities related to:

● Fuel characterisation

● Combustion

● Gasification

● Liquefaction

● Pyrolysis

● Fluidised bed technology

● Emissions control

● Use of alternative fuels and wastes

for energy production

Pyrolysis ActivitiesCurrent funding support for the use of biomass for energy is presently givenmostly to projects utilising direct combustion in systems that produce bothheat and power. Therefore, there are currently only small laboratory scalefacilities for the study of pyrolysis of biomass and other wastes. All thepyrolysis work in Portugal is currently done at INETI – DTC and the followingsubjects have been studied:

INETI is a public institution devoted to Research, Development and Demonstration (R, D&D) as well as providingtechnical, technological and laboratory assistance to industry. INETI was created in 1977 under the name ofLNETI – National Laboratory of Engineering and Industrial Technology, to integrate several governmentalinstitutions devoted to research and technical services to industry.

Equipment for the study of plastic waste Pyrolysis

● biomass flash-pyrolysis

● plastic wastes pyrolysis

● co-pyrolysis of plastic wastes

and biomass

The main aims of the work done so farhave been optimisation of the overallprocess by studying the effect of severalexperimental conditions and catalysts onreactions products, analysis and fullcharacterisation of products obtained,

and review of new pyrolysis technologiesto report them to national authoritiesand industry.

Future aims include a betterunderstanding of the processmechanism and reaction kinetics andthe construction of pilot-scale units thatwould allow a better understanding ofthe process which would subsequentlyhelp scale-up to industrial plant.

DTC – Department of Combustion and End-Use Technologies

● IBQTA-Institute of Biotechnology,Fine Chemistry and Food Technology

● IMP-Institute of Materials and Production Technologies

● ITA-Institute of Environmental Technology

● ITE-Institute of Energy Technology

● ITI-Institute of Information Technology

● CITI-Centre for Technical Informationfor Industry

● CEGTI-Centre for Technology and Innovation Management

● CEGEF-Centre for Training Management and Engineering

part 2

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Utilization of whole bio-oil

Chemicals and Materialsfrom Bio-oilBy Desmond Radlein, Resource Transforms International Ltd., Canada

The alternative approach to the isolation of individual compounds consists of exploitation of the chemicalcharacter of bio-oil to find applications for the whole oil or fractions thereof. Pyrolysis liquids contain highconcentrations of carbonyl, carboxyl, and phenolic functional groups (see figure 1) which suggests variousapplications as a reactive feedstock. This concept is illustrated by the following examples.

Fertilizers and Soil Conditioners

Feedstock Carbonyl Carbonyl Hydroxyl Phenolic Methoxyl

Maple 2.1 5.7 0.92 2.8 2.1Wheat Straw 1.4 5.3 1.40 3.0 1.1Poplar-Aspen 2.1 6.2 0.77 2.8 1.6

Peat Moss 1.2 3.0 1.30 1.8 0.7

Moles Functional Groups/kg Organic Liquid

Figure 1.

Reaction of the bio-oil with ammonia,urea and other amino compounds producesstable amides, imines and Mannich reactionproducts, etc., which are non-toxic to plantsand therefore can function as slow releaseorganic fertilizers. (Patents pending).

Typical nitrogen controlled release fertilizersvary in price from US$250/ton for sulfurcoated urea to $1250/ton for polymercoated fertilizers so a product such as this islikely to be far more valuable than simplefuel applications.

There are also additional benefits. Thecracked (pyrolytic) lignin and its reactionproducts with amino compoundsare not only good sources of humicmaterial for soil conditioning but alsoexcellent chelants or complexing agents formicronutrient trace metals like Mo, Fe, B, Zn,Mn and Cu. Functional groups also exist forbinding other nutrients like Ca, K, and P.

Besides functioning as simple organic soilconditioners, the merits of humic substancesfor control of soil acidity, ameliorationof the effects of excess Al and Fe,increasing availability of phosphate,and as crop stimulants, among otherbenefits, is well documented.

Within the context of current concernswith the reduction of greenhouse gasesthis technology may be thought of as amethod for storing carbon in the soilthereby mitigating the effects of CO2

emissions and providing a basis forsustainable agriculture and silviculture.At the same time the binding of nitrogensolves problems of nitrate and ammoniumpollution of lakes and rivers and representsa potential solution to the broader problemof the disposal of manures.

Part 1 of this feature in PyNE newsletter 4 described the opportunities forindividual chemicals. This second and concluding part focuses onthe wholeoil.

Desmond Radlein at the PyNE group meeting, May 1997

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Acetalization and Esterification

Bio-OilEthanol

ReactiveExtractionColumn

FractionationColumn

Fuel Additives(Octane Enhancers)

Flavour Chemicals

Boiler Fuels, etc.

Diesel Fuels

MolecularSieveColumn

Acetalization and Esterification of Bio OilFor fuel applications these conversions:

● reduce acidity

● increase heating value by up to 30%

● decrease the flash point

● reduce aging rate

● decrease viscosity (when excessalcohol is retained in the product).

Since the reaction products have increasedhydrophobicity and volatility there is alarge increase in the distillable fractionas well. Hence other useful products maybe more readily recovered by conventionalfractionation methods, (Figure 2). Such additional applications include:

● flavour chemicals

● octane enhancers

● solvents, resins, varnishes

● conversion to ethers

BioLime™

A final example of this approach is theproduction of BioLime™ being developed byDynamotive Corp. of Vancouver, B.C., as anagent for control of SOx and NOx emissionsin coal combustors, [8]. Whole bio-oil isreacted with lime to generate various organo-calcium salts. Compared to lime,this enables very high utilization rates ofcalcium for SOx capture. Furthermore someof the various classes of organic compoundsare effective catalysts for the destructionof nitrogen oxides. The calcium capacitycan be further enhanced by pre-oxidationof the bio-oil.

Conclusions

Figure 3 summarizes the concept of a bio-refinery based on bio-oil presented here.Efforts to proceed with the commercializationof these technologies is on-going.

We believe that these efforts will bear fruitin the near future. The authors welcomepartners and collaborators in this endeavour.

References

McAllister, R., PyNE Newsletter,

Issue 3, March, 1997.

Figure 2: Acetalisation and esterification of bio-oil

Pyrolyzer

CharConverter

Hydrolysis &Fermentation

Reaction

Reaction

Reaction

Seperation

Seperation

CatalyticCracking

Fuel Gas

Bio Oil

Anhydrosugars

NH3

Lime

Alcohol

Water

Steam/CO2

ActivatedCarbon

Ash

WoodAgriMSWSewage Sludge

Biomass BioWastes

Ethanol

Humates/OrganicNitrogen SlowRelease Fertilizers(N, Ca, Zn Fe....)

NoxoleneTM

(NOx Reduction)

BioLimeTM

NOx/SO Reduction

Fuel Enhancers,Flavour Chemicals

ChemicalFlavour

Adhesives

Diesel/Boiler Fuel,Speciality Chemicals

Synthesis Gas,Hydrogen

The reactivity of carbonyl and carboxyl groups can also be exploited by reaction with alcohols to generate acetals,ketals and esters (Patents pending). The alcohol undergoes esterification and trans-esterification with carboxylatefunctionalities and (hemi) acetalization with carbonyls. Being renewable, ethanol is the alcohol of choice.

Figure 3: Concept of a bio-refinery for chemicals and fuels by fast pyrolysis of biomass

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CNRS NancyBy Olivier Boutin, CNRS Nancy, France

Olivier Boutin is from the Laboratoire des Sciences du Genie Chimique (LSGC-CNRS-ENSIC) in Nancy, France, working under the direction of Dr Jacques Lédé. The aim of the visit was to perform the chemical analysis of a number of samples from products obtained from the thermaldecomposition of cellulose and lignin exposed to a concentrated radiation.

Figure 1 shows the equation representingthis reaction where the -OH group arereplaced by -Osi(CH3) in order to yieldmore volatile compounds.

Several tests were made to determinethe right silylating reagent and the bestconditions. The procedure followed foreach sample of pyrolysis product wasas follows:

● extract the products from the purecellulose with water

● eliminate any trace of water

● add silylating reagent and solvent

● wait enough time for the completesylilation reaction

● carry out the first analysis in a simple GC

● carry out the complete analysisin a GC-MS

The 5kWth image furnace at Nancy givesa very concentrated heat flux, higher than106 W m-2, under very clean conditions(See page 18). These are very favourableconditions for flash pyrolysis. Samples ofpure cellulose (Whatman CC31 microgranular)and pure lignin (Organicell from Dr Meierat IWC) are placed at the small (about 1cmdiameter) focus of the furnace and thenundergo rapid thermal decomposition.Several experiments have been made andthe corresponding products obtained afterquenching were taken to Hamburg in orderto determine their chemical composition.

The analysis confirmed that the celluloseused for the experiments in Nancy waspure and did not contain any trace ofhemicellulose or lignin, as also measuredby complete acid hydrolysis followed bysugar analysis with liquid chromatography. The analysis of the initial thermaldegradation products of fast pyrolysis wereanalysed by gas chromatography coupledto a mass spectrometer (GC-MS analysis).However, some of the products were foundto be too polar and did not vaporise inthe injector of the GC. Therefore, a specialsilylation method was applied to form thetrimethylsilylethers.

The following twoexchange visits took

place at the Institute ofWood Chemistry (IWC)

n Hamburg, Germany nder the supervision

f Dr Dietrich Meier.The IWC has become the

most popular place foryoung researchers who

are sponsored by thePyNe Network to visit

because of their xpertise in analysis

and characterisationand the variety of

equipment available.

Figure 1.

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15

Figure 2 shows a typical chromatogram. It shows that relatively few peaks wereobtained. In particular, two main peakswere very interesting: the peak at17.36 min was from levoglucosan and thepeak at 43.88 min was from cellobiose.

The corresponding mass spectra aregiven in Figure 3.

The particular value of the visit was tolearn about chemical analysis, especiallyon sylilated products analysed in a GC-MS. It was also interesting to develop andtest a method for the analysis of theNancy products.

VTT energy

At VTT the study is focused on physicalupgrading of pyrolysis liquids. Catalytictreatment of pyrolysis vapours has beenstudied since 1996 by using a micro-scalemodified Pyroprobe catalytic system.The study will be continued with thislarger (150g/h pyrolyser) equipment.

During the visit four experiments werecarried out, two without the catalyticreactor and two with it.

The value of the visit was to see the detailsin preparing and conducting the run and theproduct recovery system. After the visit,some small modifications were made inVTT’s equipment. The first experimental runwith birch powder was successful. The trialsand the installation of the catalytic reactorat VTT will be carried out during the summer 1997.

By Johanna Levander – VTT Energy, Finland

Johanna Levander of the Technical Research Centre of Finland (VTT)visited the Institute of Wood Chemistry (IWC) in Hamburg, Germany inJanuary 1997. VTT has a small fluid bed pyrolyser for catalytic upgradingof pyrolysis vapours similar to that of IWC, and the objective of the visitwas to improve familiarity with the equipment. Dr Dietrich Meier at IWChas a long experience in catalytic upgrading of various feedstocks andPeter Wulzinger, who has been operating the pyrolyser and coupledcatalytic reactor, was available to help with the operation.

Figure 3: Just levoglucosan the other compound is not yet verified

Figure 2: Typical chromatogram obtained in gas chromatography

16

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90

80

70

60

50

40

30

20

10

0450 600 750 900 1050 1200

Tr [K]

Yie

ld,

% b

y w

eig

ht

of

cellu

lose

TAR

GAS

CHAR

Figure 1: Final tar, gas and char yields as functions of

Tr for two particle half-thicknesses (values x 100 [m]

reported in figure) as simulated for Trea = Tr.

Experimental data by Scott et al. (1988) (empty symbols)

and by Shafizadeh et al. (1979) (filled symbols) are included

for comparison purposes ( gas, tar, char).

References

1. Di Blasi, Multi-phase moisture transfer in the

high-temperature drying of wood particles, Chemical

Engineering Science, in press, 1997.

2. Di Blasi, Heat, momentum and mass transfer through a

shrinking biomass particle exposed to thermal radiation,

Chemical Engineering Science, 51: 1121-1132, 1996.

3. Di Blasi, Kinetic and heat transfer control in the slow

and flash pyrolysis of solids, Ind. Eng. Chem.

Res., 35:37-47, 1996.

4. Di Blasi, Heat transfer mechanisms and multi-step

kinetics in the ablative pyrolysis of cellulose, Chemical

Engineering Science, 51: 2211-2220, 1996.

5. Lanzetta, C. Di Blasi and F. Buonanno, An experimental

investigation of heat transfer limitations in the

flash pyrolysis of cellulose, Ind. Eng. Chem.

Res., 36:542-552, 1997.

By Colomba Di Blasi, University of Napoli “Federico II”, Italy

Pyrolysis modellingThe development of mathematical modelsfor biomass pyrolysis is an important partof the research activity on thermochemicalconversion of solid fuels currently underwayat the Department of Chemical Engineeringof the University of Napoli “Federico II”.

The main purposes of the modellingactivity are:

1) to identify system characteristics usefulto experiment programming,

2) to analyse the effects of processparameters in order to provide useful datafor the design and optimisation of chemicalreactors and other process equipment.

Detailed mathematical models have beendeveloped for the dynamics of single-particledrying [1] and pyrolysis taking place throughindirect external heating (convection andradiation) [2, 3] and direct external heating(hot-plate contact) [4]. Transport models forflash pyrolysis units (fluidised-bed andablative reactors) are under development.Also, laboratory scale experiments arecarried out to get “input data” for processsimulation, such as the kinetic constants forflash pyrolysis [5] and process variablemeasurements such as conversion time,temperature dynamics, product yields, gasand liquid composition, for model validation.

The mathematical description of particledrying includes the phenomena of watervapour convection and diffusion andcapillary water convection in the pores ofthe particle, and bound water diffusion inthe solid wood. Momentum transfer for theliquid and the gas phase, is describedaccording to the multiphase Darcy law.

Local thermodynamic equilibrium is assumed,with a sorption isotherm that couples themoisture contents in the solid and the gasphase. Predictions which exhibit goodquantitative agreement with experimental data, have been used to determine theconditions for fast and slow drying and the controlling mechanisms.

In the pyrolysis models, primary andsecondary chemical kinetics are describedby means of lumped-parameter mechanisms,where the products are grouped into char,gas and tar. For the case of indirect heating,the transport model describes the mainphysical processes occurring across theporous particle, that is:

● property (porosity, permeability,thermal conductivity, thermal capacity,mass diffusivity) variation with the conversion level

● accumulation of volatile speciesmass and enthalpy within the pores

● heat transfer by convection,conduction and radiation

● convective and diffusive transport of volatile species

● gas pressure and velocity variations

● particle shrink age and/or swelling

Furthermore, a two-dimensional unsteadyversion of the model equations has allowedthe role played by medium anisotropy on thepyrolysis characteristics to be investigated.

Extensive numerical simulations of theproblem of a biomass particle have beenused to analyse time and space evolution ofthe main variables and product distributionas the heating conditions and the particleproperties are varied.

For the case of hot plate contact, a cylindrical particle pressed against a hot,spinning disk has been modelled. For mainlines, all the physical processes listed abovehave been taken into consideration with thefurther description of the formation of amolten phase and the subsequentvaporisation process.

Simulations have confirmed some importantexperimental findings.

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The Idea

One solution is to co-combust straw withcoal in existing boilers by using a fluid bedpyrolysis unit to first convert the biomassinto a gas. Traditionally, co-combustion ofstraw and coal is a task for daring utilities

with expendableboilers as the alkali(potassium andsodium) andchlorine content inthe straw acceleratecorrosion. But bypre-treating thestraw in a fluid bedpyrolysis unit, mostof the potassium,sodium, andchlorine can be keptout of the volatilephase and retainedin the char.

Such a pyrolysisunit has been underdevelopment since

1994 by dk-TEKNIK Energy and Environmentand the Department of Energy Engineering(DEE) at the Technical University of Denmarkand is shown in Figure 1. DEE is leadingthe field in two-stage gasification anddk-TEKNIK is an independent consultancyparticipating in several R&D projects onbiomass utilisation.

Operation

The straw is pyrolysed in the fluid bedpyrolysis reactor and the char is separatedfrom the gases in a cyclone. By keeping thepyrolysis temperature below a certain level,the bulk of the sodium, potassium andchlorine in the input straw remains inthe char. The gas, with only limitedamounts of these harmful components,is partly used for fluidisation of thepyrolyser by recirculation with a blowerand partly sent to a conventional powerplant boiler.

The majority of the energy originally inthe straw is transferred to this gas whilethe char retains most of the alkali metalsalong with other residues. These residuescan be utilised as the biomass ash is notcontaminated with fossil fuel ash.

Use a lot of biomass to produce electricity – and do it fast! This was essentially the message from the Danish authorities when, in 1993, they directed the utilities toincrease the use of straw and wood by 1.4 million tonnes per year by 2000. But how can this be accomplishedin such a short period of time?

Co-combustionofbiomassbasedon afluid bed Pyrolysis Unit

Figure 2: Results from straw experiment

The bench scale fluid bed pyrolysis unit with part of theinstrumentation, ready for experiments

By Søren Houmøller, dk-TEKNIK Energy and Environment, Denmark

Results

Experiments with a bench-scale reactor haveshown that the energy content of the gasincreases with increasing temperature, so tosupply as much energy as possible to theboiler, the pyrolysis temperature should beas high as possible. To retain the alkali andchlorine in the char, however, the pyrolysistemperature needs to be low.

Below 500ºC about 45 per cent of energyin the straw is contained in the char fractionalong with all of the potassium and sodiumand about 80 per cent of the chlorine. At550ºC the sodium, potassium and chlorinelevels start to decrease and continue toreduce as the pyrolysis temperatureincreases. The results are shown in Figure 2.The fluid bed experiments generally show alower retention of harmful components andless energy than batch testing in an oven.

These results show that straw can beconverted into a usable gas as expectedand that the unit can help the utilitiesto solve their problems with electricityproduction from straw.

Fossil residue

Fo

ssil

fuel

ed p

ow

er p

lan

t b

oile

r

Pyr

oly

zer

Gas

Biofuel residue

Biofuel

120%

100%

80%

60%

40%

20%

0%

% o

f in

fed

in s

traw

ret

aine

d in

cha

r

400 450 500 550 600 650 700 750

Temperature in ºC

Potassium retained in char

Sodium retained in char

Chlorine retained in charEnergy retained in char

Mass fraction of char (%) of infeed fuel

Figure 1.

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Solar energy and biomass pyrolysisBy Jacques Lédé, CNRS-ENSIC, France

Solar energy is responsible forthe formation of biomass by theprocess of photosynthesis. Solarenergy can also be used with twodifferent objectives: as a heatsource in thermochemicalconversion processes of biomassand/or for studying its fastelementary reactions of thermaldecomposition. As the maximumavailable heat flux delivered bythe sun on the earth’s surfacedoes not exceed 1000 W/m2,it is necessary to concentratethe solar radiation.

Available concentrating technologies

There are three main systems used forsolar concentration:

1. Parabolic troughs

The reflective surface of a parabolic troughconcentrates sunlight onto a receiver tubelocated along the trough’s focal line. However concentration ratios of only a few tens are reached and temperaturesare not high enough to perform pyrolysis.

2. Power towers

Several hundreds of mirrors (heliostats)track the sun and reflect the solar energyonto a receiver mounted at the top of acentral tower. Such big plants are currentlyunder development in several countries,where powers of several MW are obtained. These plants are usually designed for theconversion of solar energy to electricity. It is anticipated that they could be alsoconsidered in the future for high temperaturechemistry. These power towers usually achieveconcentration ratios of 300 to 1500 and canoperate at temperatures up to about 1500°C.

3. Dish concentrators, solar furnaces

The solar parallel radiation is concentratedinside a receiver located at the focal zone ofa parabolic mirror. Powers as high as 1 MWcan be reached as well as concentrationratios of several thousands and temperaturesabove 3000°C. The heat flux densities in thefocal zone can reach 107W/m2.

Biomass solar thermalconversion processes

The high heat fluxes and temperaturesthat can be achieved after sunlightconcentration can be favourably used forthe gasification and/or pyrolysis of biomass.The concentrated radiation can be absorbedeither directly by the biomass particlesthat react in conditions of high purity, orthrough a wall (or inert or catalyst particles)indirectly heating the biomass. There areseveral main advantages of such cleanprocesses. Solar energy provides thenecessary heat of the reaction (sensible heatand enthalpy of the endothermic steps) withseveral advantages: economy of external fuel;transformation of the whole biomass intovaluable compounds; products less dilutedwith N2, and CO2; no pollution from bycombustion gases. The energy recovered inthe products is the sum of the energy storedduring photosynthesis and under the formof enthalpy of reaction. The products areliberated into a cool environment with the possibility of thermal quenching.

Several countries have reported laboratoryscale experiments and pilot scale projectsin the field of solar gasification and pyrolysissuch as France, USA, Israel, Germany andSwitzerland. In addition, these activitiesbring the opportunity to design new typesof reactors with optimal combination of solarenergy absorption efficiency with biomassfeeding and conversion and developmentnew quenching devices.

There are potential markets in thesouthern zones of Europe mainly aroundthe Mediterranean, but also in othercountries such as Brazil, India and Australia. Solar biomass conversion can be particularlyattractive in very sunny areas where largequantities of agricultural wastes are producedfor example from greenhouses.

Nancy’s SKW image furnace

Flash pyrolysis of small samples of biomass at th focus

of a solar simulator (LSGC-CNRS, Nancy-France).

The reaction occurs inside a receiver located at the first

focus of an elliptical mirror (right part of the photo)

reflecting the light delivered by a high power Xenon lamp

associated to another elliptical mirror (on the left side

of the set up, not seen on the photo).

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Concentrated radiation for studyingthe fundamental aspect of biomass pyrolysis

The heat flux densities that can be obtainedinside a concentrated radiation zone canbe easily modified by changing the level ofconcentration and/or the level of occultationof the incident radiation. So, it is possibleto control and also to measure the availableheat flux densities inside relatively largedomains. If samples of biomass are put atthe focus of a concentrator, it is hence easyto precisely know in which conditions thepyrolysis occurs.

The heat fluxes densities that can beachieved in these conditions can be similarto those existing in ablative pyrolysis.However the mass transfer efficienciesare quite different. The comparison of theexperimental results obtained in bothcases, and the use of a mathematical model,provide valuable information on the kineticsof some of the competitive and consecutiveprimary reactions occurring during biomassthermal decomposition.

Such work is being carried out in the CNRSLaboratoire des Sciences du Génie Chimiqueof Nancy (France) in the framework of anAGRICE (ADEME) contract. At the presenttime, small scale experiments are beingperformed in a solar simulator (imagefurnace) operating with a high power xenonlamp associated with two elliptical mirrorsas shown in the photographs opposite. The achievable heat flux densities can behigher than 5*106 W/m2 inside a circle ofapproximately 0.5 cm2. The work is made incollaboration with the CNRS-IMP Laboratoryof Odeillo (France) where experiments areplanned in a 2.5 kW solar furnace.

Conclusion

These unusual aspects of biomass pyrolysisopen new and fascinating fields of researchand applications. They also give theopportunity for fruitful collaborationbetween two different scientific communitiesinvolved in the fields of “Solar Chemistry”(this is the subject of the Task II of the IEASolarPACES programme) and of biomassthermochemical conversion.

Odeillo’s 1MW solar furnace

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By Stefan Czernik, NREL, USA

Biomass pyrolysis activities at NREL in 1997/1998

The NREL activities related to biomass pyrolysis are supportedby three Department of Energy programs; Biomass Power,Industrial Technologies, and Hydrogen.

Figure 3: Tubular fixed bed reactor

Figure 1: The Thermochemical Process Development Unit

The facilities used to carry out the projectshave been previously described (No. 3 issue of the PyNE newsletter).

The Biomass Power Program sponsorsresearch on development of integratedbiomass gasification/fuel cell system (IGFC). The Thermochemical Process DevelopmentUnit (modified vortex ablative pyrolysisreactor system – see Figure 1, is operatedin pyrolysis/gasification mode to generategas suitable (after conditioning) for usein a molten carbonate fuel cell. The vortexreactor operating conditions are similar tothose used for the oil generation; biomassfeed rate is 15-20 kg/h, reactor wall ismaintained at the temperature of 650°C.

However, steam is used as a carrier gasand pyrolysis vapors are thermally crackedin the secondary reactor at 800-850°C.Conversion of biomass to gas is of theorder of 80%. The gas composition isvery similar to that generated in Battelledual fluidised bed system. This summer a molten carbonate fuel cell

will be coupled to the PDU to determineits operability using gas generated frombiomass thermo-processing. Though currentlydedicated to generate gas, the PDU can beany time used to produce bio-oils just bybypassing the vapor cracker.

The Office of Industrial Technologiessupports the NREL work on producingchemicals for brightness stabilization ofpaper. The focus of this project is theisolation of specific pyrolysis oil fractionthat effectively slows down yellowingof paper prepared from bleachedthermo-mechanical pulp. NREL is developingthe product in collaboration with MineralTechnologies, Inc. A four-inch diameterfluidised bed reactor is used to generatebio-oils for this study and is shownin Figure 2.

Figure 2: Four-inch diameter fluidised bed reactor

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R&D news from canada

Bio-Oil Utilisation Gas Turbines

The Hydrogen Program sponsors NRELBiomass to Hydrogen project. The studiedapproach to generate hydrogen from biomassproposes combined two-stage processing;fast pyrolysis to produce bio-oil and catalyticsteam reforming of the bio-oil to hydrogenand carbon dioxide. The efforts havebeen focused on the second stage, steamreforming bio-oil and its fractions.The research performed using a tubularfixed-bed reactor system proved technicalfeasibility of the concept as shown inFigure 3. Future experiments will bemostly carried out using a two-inch diameterfluidized bed reactor with a commercialnickel-based catalyst shown in Figure 4.

In addition to the DOE sponsored researchNREL also carries out three biomass pyrolysisprojects funded by private companies.

By Ed Hogan, Natural Resources Canada, Canada

Figure 4: Two-inch diameter fluidised bed reactor

Orenda is finalising a project thatdemonstrated the “Proof of Principle” of theconcept of utilising biomass pyrolysis oil ina gas turbine. Orenda was able to achievestable operation of their GT2500 2.5 MWeengine using 100% bio-oil over itsoperational entire range. The turbine hasbeen operated using various ratios ofbio-oil and diesel with a total of 13,000litres of bio-oil combusted.

Orenda is preparing to start a follow-oncommercialisation programme whichwill examine:

● upgrading fuel quality by post productionprocessing; redesign of sections of the GT2500 to deal with the viscosity,ash, acidity and particulate contentof the bio-oil

● performance and emission tests overlonger term engine operation withupgraded hot section components(up to 150 hours)

● development of specifications for theengine, auxiliary, and fuel handling systems for commercial application.

The successful completion of thiscommercialisation phase will allow Orendato provide warranties for the use of theturbine with biomass pyrolysis oils.

Microemulsions

The CANMET Energy Technology Centrehas developed a pyrolysis liquid in dieseloil micro-emulsion fuel. Tests to dateindicate that stable emulsions of bio-oilin diesel ranging from 5% - 40% can beproduced. Bio-oil produced from hardwood,softwood and agricultural feedstocks havebeen successfully processed and variousqualities of diesel fuel can be used.The next phase of the work will examineadditional bio-oil feedstocks, furtheroptimise the process and examine fuelquality and combustion characteristicsof the various emulsion mixtures.

Biodegradability

In other recently completed work, RTI Ltd.has performed preliminary studies on thebiodegradability of bio-oil using respirometrymethods. It was determined that bio-oilis highly degradable, much more thanhydrocarbon fuels. This was especiallytrue if the bio-oil is brought to a neutralpH. These results are important assurancesconcerning the safety of pyrolysis oils incommercial applications. A final reportoutlining the test procedures and resultsis available from RTI Ltd.

22

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Book reviewsBiomass gastification & pyrolysis state of the artand future prospects

Edited by M. Kaltschmitt and A.V.Bridgwater 1997, 550 pp, ECU 150CPL Scientific Limited, 43 Kingfisher Court, Newbury,Berkshire RG14 5SJ, U.K ISBN: 1 872691 714

Gasification and Pyrolysis are very promisingoptions for further use of biomass in Europeespecially for electricity production. Bothtechnologies have made significant progressover the last three years and althoughneither is truly economic in the absence offiscal incentives, the scientific and technicalknowledge base has grown considerably andis thereby aiding the improvement of the technology and reducing costs.

This book includes all the papers offeredat the final meeting of the EC sponsoredGasification Network which was combinedwith a meeting of the Pyrolysis Network -PyNE. This conference was held in Stuttgartfrom 9-11 April 1997.

Several overviews are included in whichthe status and prospects of biomass forenergy, the development of gasificationand pyrolysis, the characteristics of biomassand of its conversion products are discussed.Two sections follow dedicated to thepresentations of gasification and pyrolysis.Conclusions and recommendations completethe work.

In the gasification section, research andapplications in fixed bed and in fluidized bedreactors are reported. Experiences withdemonstration plants are also explained.A large part of the proceedings is dedicatedto gas cleaning; tar removal andenvironmental aspects of gasification.

The pyrolysis section contains a state ofthe art review of pyrolysis processes andincludes some experiences on pilot anddemonstration plants. Subsequently severalpapers are dedicated to the upgradingand characterisation of the bio-oils.The bio-oil as source of chemicals and theutilization as fuel for engines or boilersare also embraced. A description of PyNE,the pyrolysis network for Europe, endsthe section.

Biomass Gasification & Pyrolysis containsmore than 50 papers and represents avery useful update for everyone to knowabout the latest developments and successesin both areas.

Making a business frombiomass in energy, environment,chemicals, fibres and materials

Edited by R.P. Overend and E. Chornet 1998 New York, 2 Vol. US $ 400Elsevier Science Inc., 660 White Plains Road, Tarrytown,New York 10591-5153, U.S.A.ISBN: 0080429963

The work, published in two volumes, reportsthe proceedings of the 3rd BiomassConference of the Americas, Montréal,Québec, Canada, 24-29 August 1997.

The papers reflect the theme that a novelbiomass industry is progressively emerging,with diversified technologies andapplications, complementing and expandingupon traditional biomass sectors.

Technology transfer, scale-up demonstrations,commercial applications and new businessdevelopment ventures are presented indepth. Emphasis is placed on how to makea profitable business from biomass within a vision on sustainability, flexible chemicalprocessing and energy efficiency.

The proceedings comprise the followingkey areas:

● Resource Base – cost effectivedevelopment and expansion ofbiomass production.

● Environmental Impact and Sustainability– issues surrounding increased biomassproduction and usage.

● Heat and Power – conversion of biomassto bioenergy in order to produce heatand power and combined heat andpower (CHP).

● Pyrolysis and Bio-oils – an emergingarea at the intersection of energyand chemicals.

● Chemicals and Materials – productdevelopment based upon the conversionof biomass to chemicals and materials.

● Biofuels - major technological advancesin this area.

● Anaerobic digestion – complementaryviewpoints, scientific and commercialapplications.

● Systems Integration – biomass-drivenindustries as unique opportunities forfuture generations.

● Economics and Business – case studiesof specific biomass projects.

This publication is an invaluablereference tool for those engaged inresearch and the commercial applicationsof the above emerging biomass andbioenergy technologies.

Physical characterisation of biomass-based pyrolysis liquids

Anja Oasmaa, Ero Leppamaki, Paivi Koponen, Johanna Levander, Eija Tapola 1997, 76 pp.VTT Technical Research Centreof Finland, Vuorimiehentie 5, P.O. Box 2000, FIN-02044 VTT FinlandISBN: 951-38-5051

Biomass pyrolysis liquids differ a great dealfrom petroleum-based fuels in both physicalproperties and chemical composition.Pyrolysis liquids contain more water andusually more solids, are acidic, have a lowheating value and are unstable when heated,especially in air. Due to these differences thestandard fuel oil methods developed formineral oils may not be suitable as such forpyrolysis liquids.

The book reports a study performed by VTT,focuses on testing and modifying thestandard fuel oil analyses routinely used.

The book is divided in two parts. In thefirst one the main characteristics of bio-oilsand the problems linked with theirdeterminations are discussed. The secondpart consists of 13 appendices in whichsome analytical methods and results arebriefly described.

This book represents a useful referencepoint for researches engaged in the studyof the biomass pyrolysis process and in thedevelopment of bio-oils applications.

Contents:

1. Introduction

2. Production and Homogeneityof Pyrolysis Liquids

3. Sampling

4. Water, Ash and Elemental

5. Fuel-oil Properties

6. Acidity and Material corrosion

7. Miscibility

8. Lubricity

9. Stability

10. Recommendations

11. References

12. Appendices 1-13

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International Workshop CUBASOLAR ’98Science Development and Solidarity

Venue: Habana, CubaDate: 13-17 April 1998Contact: SOCIE, Calle Luz No. 375,

e/ Picota y Compostcla, Havana Vieja C Havana, Cuba

Tel: +537 612846Fax: +537 331732 and 332699

Energetic and Material Utilisationof Renewable Resources

Venue: GermanyDate: 20-22 April 1998Contact: DGMK, Frau Christa Jenke,

P.B. 60 05 49, D-22205, Hamburg

MAVA ’98International Business Convention onThermal Treatment and Energy Recoveryfrom Waste and Biomass

Venue: SwitzerlandDate: 4-5 May 1998Contact: Hubert Klun or Christophe

Estermann, Case Postalel 293, CH-1000 Lausanne 22, Switzerland

Tel: +41 24 426 11 11Fax: +41 24 426 77 77E-mail: mava@fastnet.ch

Pyrolysis ’9814th International Symposium onAnalytical and Applied Pyrolysis

Venue: Munich, GermanyDate: 18-20 May 1998Contact: c/o Ulla Schrodel, GSF -

Forschungszentrum, Congress Service, Postfach 11 29, D-85758 Neuherberg, Germany

Tel: +49 89 3187 3030/2669Fax: +49 89 3187 3362

AGROENVIRON ’98 - Towards 21st CenturyInternational Symposium

Venue: PakistanDate: 25-30 May 1998Contact: Faculty of Agricultural Engineering

& Technology, University of Agriculture, Faisalabad, Pakistan

Tel: +92 41 3028189 Ext 434Fax: +92 41 647846/30769

Biomass for Energy and Industry10th European Conference andTechnology Exhibition

Venue: Congress Centre Wurzburg, GermanyDate: 8-11 June 1998Contact: WIP, Sylvensteinstrasse 2,

D-81369 Munchen, GermanyTel: +49 89 720 1232Fax: +49 89 720 1291Website: http://www.wip.tnet.de

The 9th Global WarmingInternational Conference

Venue: Hong KongDate: 8-11 June 1998Contact: GW9 Conference Secretariat,

PO Box 5275, Woodridge, IL 60517, USA.

Tel: +1 630 910 1551Fax: +1 630 910 1561

2nd Asia Pacific Conference onSustainable Energy and Energyand Environmental Technology

Venue: ANA Hotel, Gold Coast, Australia Date: 14-17 June 1998Contact: APCSEET ’98 SecretariatTel: +61 7336 90477Fax: +61 7336 91512Email: apc@cheque.uq.edu.au

Power Production from Biomass III

Venue: Hanasaari Cultural Centre, FinlandDate: 14-15 September 1998Contact: Mrs Maija Korhonen, VTT Energy,

Seminar Power Production from Biomass III, PO Box 1601, FIN-02044 VTT, Espoo, Finland

Fax: +358 9 460 493Email: Maija.Korhonen@vtt.fi

World Renewable Energy Congress

Venue: Florence, ItalyDate: 20-25 September 1998Contact: Professor A A M Sayigh,

World Renewable Energy Network, 147 Hilmanton, Lower Earley, Reading, RG6 4HN, UK

Tel: +44 (0) 118 961 1364Fax: +44 (0) 118 961 1365

Gasification - The Gateway toa Cleaner Future

Venue: Dresden Hilton, Dresden, GermanyDate: 23-24 September 1998Contact: Tracy Lepkowska, (Gasif 3),

IChemE Conference Department, 165-189 Railway Terrace, Rugby, Warwickshire, CV21 3HQ, UK.

Tel: +44 (0)1788 578214Fax: +44 (0)1788 577182Email: tlepkowska@icheme.org.uk

8th Biennial Conference

Venue: Madison, WisconsinDate: 4-8 October 1998Contact: Fred Kuzel or Naureen Rana,

Great Lakes Regional BiomassEnergy Program, 35 East Wacker Drive, Suite 1850, Chicago, IL 60601, USA

Tel: +1 312 407 0177Fax: +1 312 407 0038Email: fkuzel@cglg.org OR

nrana@cglg.orgWebsite: http://www.cglg.org/bioenergy98

Materials and Energy from Refuse

Venue: Oostende, BelgiumDate: 12-14 October 1998Contact: Ms Rita Peys, c/o Technologisch

Instituut vzw, Desguinlei 214,B-2018 Antwerpen, Belgium.

Tel: +32 3 216 09 96Fax: +32 3 216 06 89Email: mer@ti.kviv.beWebsite: http://www.kviv.be/ti/mer.htm

2nd International ConferenceLCA in Agriculture, Agro-Industry and Forestry

Venue: Brussels, BelgiumDate: 3-4 December 1998Contact: Mrs Mieke Engelen, Product

and Process Assessment, VITO, Boeretang 200, B-2400 Mol, Belgium.

Tel: +32 14 33 58 53Fax: +32 14 32 11 85Email: engelenm@vito.be

SUSTAIN ’99The World Sustainable Energy Trade Fair

Venue: Amsterdam RAI, The NetherlandsDate: 25-27 May 1999Tel: +44 181 289 8989Fax: +44 181 289 8484Website: http://www.emml.com

Diary of Events

Co-ordinator

Tony BridgwaterAston UniversityBirminghamB4 7ETUNITED KINGDOMTel: +44 121 359 3611Fax: +44 121 359 6814/4094Email: a.v.bridgwater@aston.ac.uk

Austria

Maximilian LauerInstitute for Energy ResearchJoanneum ResearchElisabethstrasse 11A-8010 GrazAUSTRIATel: +43 316 876 332Fax: +43 316 876 320Email: max.lauer@joanneum.ac.at

Belgium

Rosanna MaggiUniversité Catholique de LouvainUnite de Catalyse et Chimie des MatériauxDivisésPlace Croix du Sud 2/17Louvain-la-Neuve 1348BELGIUMTel: +32 10 473 652Fax: +32 10 473 649Email: maggi@cata.ucl.ac.be

Canada

Jan PiskorzRTI - Resource Transforms International Ltd110 Baffin Place, Unit 5WaterlooOntarioN2V 1Z7CANADATel: +1 519 884 4910Fax: +1 519 884 7681Email: jpiskorz@rtiltd.com

Denmark

Karsten PedersenDanish Technological Institute Technology ParkAarhus C, DK-8000DENMARKTel: +45 89 43 8617Fax: +45 89 43 8673Email: karsten.pedersen@dti.dk

Finland

Anja OasmaaVTT EnergyFuel Processing LaboratoryPO Box 1601EspooFIN-02044 VTTFINLANDTel: +358 9 456 5517Fax: +358 9 460 493Email: Anja.Oasmaa@vtt.fi

France

Philippe GirardCirad Forêt Maison de la Technologie73 rue J.F. BretonBP5035Montpellier Cedex 34032FRANCETel: +33 467 61 44 90Fax: +33 467 61 65 15Email: girard.p@cirad.fr

Germany

Dietrich MeierBFH-Institute for Wood ChemistryLeuschnerstrasse 91D-21031 HamburgGERMANYTel: +49 40 739 62 517Fax: +49 40 739 62 296/480Email: dmeier@aixh0501.holz.uni-hamburg.de

Greece

Yannis BoukisC.R.E.S. – Biomass Department19th km Athinon Marathona AvePikermi – AttikisGR - 190 09GREECETel: +30 1 60 39 900Fax: +30 1 60 39 904/905Email: ibookis@cresdb.cress.ariadne-t.gr

Ireland

Pearse BuckleyUniversity of DublinDept of Civil, Structural & EnvironmentalEngineeringMuseum Building, Trinity CollegeDublin 2IRELANDTel: +353 1 608 2343Fax: +353 1 677 3072Email: pbuckley@tcd.ie

Italy

Leonetto ContiUniversity of SassariDipartimento di ChimicaVia Vienna 2Sassari I–07100ITALYTel: +39 79 229533Fax: +39 79 229559/212069Email: conti@ssmain.uniss.it

Netherlands

Wolter PrinsTwente University of Technology BTGChemical Engineering LaboratoryPO Box 2177500 AE EnschedeNETHERLANDSTel: +31 53 489 2891Fax: +31 53 489 4774Email: w.prins@ct.utwente.nl

Norway

Morten GronliSINTEF EnergyDepartment of Thermal Energy and Hydropower7034 TrondheimNORWAYTel: +47 73 59 37 25Fax: +47 73 59 37 25Email: Morten.Gronli@energy.sintef.no

Portugal

Filomena PintoINETI-ITE-DTCAzinhaga dos LameiroEstrada do Paço do Lumiar1699 Lisboa CodexPORTUGALTel: +351 1 716 52 99Fax: +351 1 716 46 35Email: Filomena.Pinto@ite.ineti.pt

Spain

Jesus ArauzoUniversidad de ZaragozaChemical and Environmental EngineeringDepartmentMaria de Luna 3Zaragoza 50015SPAINTel: +34 97 676 1878/60Fax: +34 97 676 1861Email: qtarauzo@posta.unizar.es

Sweden

Erik RensfeltTPS Termiska Processer ABStudsvikS-611 82 NykopingSWEDENTel: +46 155 221385Fax: +46 155 263052Email: erik.rensfelt@tps.se

USA

Stefan CzernikNREL1617 Cole BoulevardGoldenColorado80401-3393USATel: +1 303 275 3821Fax: +1 303 275 3896Email: czerniks@tcplink.nrel.gov

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The PyNe newsletter is published by the Bio-Energy Research Group, Aston University, UK and is sponsored by the FAIRProgramme of the European Commission DGXII and IEA Bioenergy.

For further details or offers to contribute, please contact Claire Humphreys (see inside front cover for details).Any opinions published are those of the contributors and do not reflect any policies of the EC or any other organisation. EoE W

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