BIOMASS BASED ENERGY INTERMEDIATES BOOSTINGBIOFUEL PRODUCTIONA EUROPEAN RESEARCH PROJECTON RENEWABLE ENERGIES

www.bioboost.eu

To increase the share of biomass for renewable energysupply in Europe conversion pathways which are lowcost and energy efficient, as well as flexible infeedstock are demanded. The BioBoost project aimsto make a substantial improvement towards increasingthe efficiency of the use of biomass and organicresidues in the future. The project focuses on de-central conversion of biomass to optimised, highenergy density carriers, which can be utilised eitherdirectly in small scale combined heat and power (CHP)plants or in large scale applications for the synthesisof transportation fuels and chemicals. Dry as well aswet residual biomass and organic waste are used asfeedstock for conversion. Due to their secondarynature, these feedstocks have the potential for highenvironmental sustainability, and in the case of straw,it may even strengthen food production thancompeting to it. However, perennial lignocellulosicenergy crops and forest residues are included as apossibility to compensate the seasonal occurrence offor example straw. In the BioBoost project, these typesof biomass are converted by means of fuel-flexiblethermo-chemical processes such as fast pyrolysis,catalytic pyrolysis and hydrothermal carbonisation(HTC) to produce stable, intermediate energy carriersin the form of bio-oil, bio-coal or bio-slurries(biosyncrude). For straw, as an example, the energydensity of the carrier can be increased by a factor of10 to 15, enabling economic long range transportationfrom several regionally distributed conversion plantsto few central large scale gasification plants for bio-fuel production.

ABSTRACTConverting residual biomass into high energy densityintermediate energy carriers for heat, electrical power,transportation fuels and chemicals production is theaim of the collaborative EU-project BioBoost (Biomassbased energy intermediates boosting biofuelproduction). Exemplary, BioBoost investigates threepromising conversion pathways for several residualbiomass feedstocks which are converted by fastpyrolysis, catalytic pyrolysis or hydrothermalcarbonisation to intermediate energy carriers forsubsequent use in different applications. A heuristictransportation model is being developed andintegrated into the environmental and economicassessment. The applicability of the different energycarriers is investigated in existing and upcomingapplications for heat and power production, syntheticfuels and chemicals production as well as bio-crudefor refineries. The project combines complementaryexpertise from 13 partners of six member countriesrepresenting research institutions, chemical industry,and energy suppliers. The collaborative BioBoostproject is coordinated by the Karlsruhe Institute ofTechnology (KIT) and is funded by the 7 Frameworkprogramme of the European Union under grantagreement 282873 (www.bioboost.eu).

BIOMASS BASED ENERGY INTERMEDIATES BOOSTINGBIOFUEL PRODUCTION

A EUROPEAN RESEARCHPROJECT ON RENEWABLEENERGIES

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A logistic model of the supply chain taking intoaccount de-central and central conversion scenarioswith different types of energy carriers is set up andvalidated allowing the determination of minimumcosts, the number and location of de-central andcentral conversion sites. A techno-economic andenvironmental assessment of the value chainssupports the optimisation of processes and productsand allows for comparison of the processes underconsideration and to other conversion routes. Theapplication of energy carriers is investigated withpartners from industry for heat and power production,synthetic fuels & chemicals, and as bio-crude forrefineries. Coordinated by the Karlsruhe Instituteof Technology (KIT) 13 partners from industry,universities and research institutions take part in thecollaborative project, contributing the main objectives:

• To develop supply concepts of residual biomass forde-central conversion plants

• Convert biomass to intermediate energy carriers

• Improve the economic performance of the energycarrier by investigating methods for the recovery ofhigh value chemicals and nutrients from pyrolysiscondensates and HTC process water

• Optimised biomass and energy carrier logistics

• Clarify and test the technical and economic utilisationpaths of energy carrier

• Investigate the techno-economic feasibility andenvironmental sustainability of bio-energy carrierpathways.

Accordingly, the main research areas are structured inwork packages as depicted in Fig. 1:

• Identification of residual biomass potential in EU-28and development of supply concepts of for de-centralconversion plants (WP1)

• Conversion of biomass to intermediate energy carriersby thermo-chemical processes (WP2)

• Improvement of the economic performance of theenergy carrier by investigating the recovery of highvalue chemicals and nutrients from conversionprocesses (WP3)

• Development of a simulation model optimisingbiomass and energy carrier logistics (WP4)

• Clarification and testing the technical and economicutilisation paths of energy carrier (WP5)

• Investigation of the techno-economic feasibility andenvironmental sustainability of the selected bioenergycarrier pathways (WP6)

Fig. 1: BioBoost project structure and

scientific/technical work packages

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FEEDSTOCK POTENTIAL AND SUPPLY COSTSThe conversion technologies fast pyrolysis, catalyticpyrolysis and hydrothermal carbonisation studied inthe BioBoost project make us of a broad feedstockspectrum of lignocellulosic materials from dry to wet.Suitable biogenic resources occur in various residueand waste streams from agriculture, forestry, landcultivation and management, food processing andsettlement. Consequently, in BioBoost the feedstockpotential of agricultural residues, organic wastes andforestry residues in EU-27 + Switzerland has beenraised considering the following types of biomass:

• Agricultural (straw, orchard’s pruning, hay) andanimal residues (manure),

• Forestry residues,

• Natural conservation matter (urban maintenance ofgreen areas, hay and shrubs),

• Roadside vegetation,

• Urban and industrial waste (biodegradable municipalwaste, selected waste from the food and woodindustry).

The estimates were conducted at IUNG for geocodestandard NUTS-3 areas. In BioBoost, such acomprehensive EU wide review has been carried outin such spatial scale for the first time. The regionalNUTS-3 level provides the typical scale for thedevelopment of distributed energy scenarios. Themain pre-condition for the potential modelling ofthese regions was to use only waste and residuesbiomass, which do not compete with food productionand to respect the principles of sustainable productionand environmental protection. The modelled results ofthe biomass potential have been illustrated by mapsof theoretical and technical potentials in the NUTS-3regions (see Fig. 2). Additionally, normalised potentialswere developed for visualisation of the biomassdensity and spatial variability in larger regions. On thisbasis the amount of biomass and its spatial densityand energy content is raised. The largest potential ofbiomass is provided by straw with a share of 37%related to mass and of 48% regarding the energycontent. The second largest potential can begenerated from forestry residues (29%, both in termsof mass share and energy content). Another promisingresource is biodegradable municipal waste (17% of thebiomass and 12% of the energy content). Other types

Fig. 2: Total technical biomass potential (left) and total density of biomass (right) in EU-27 and Switzerland

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of biomass do not have much significance in theEuropean energy sector. In certain areas, individualtypes of biomass may play a regional role. All data onbiomass potential will be made available via aGeographic Information System (GIS Server) and areincluded in the logistic optimisation model, which alsowill become available as a internet tool.

For the techno-economic assessment, biomass supplycosts are mandatory. In BioBoost reference has beenmade to published information by SYNCOM. As canbe expected, results of biomass provision costsconsiderations are, that use of waste is more economicthan use of residues, that dry feedstocks is moreexpensive than wet ones (on an energy basis), andthat ash-rich feedstocks are more economic than low-ash types of biomass, if appropriate technology isavailable for their treatment.

Straw collection was assessed as difference to leavingit on the field in terms of fertilizer withdrawal andreplacement costs, baling and bale chasing technologyas well as implications of field size, straw amount andlabour costs. Applying the most efficient technologyfor the supply of several ten- to hundred-thousandtonnes to de-centralised conversion plants leads tostraw costs free field side stack between €31 and €39per tonne. This is in contrast to average prices between€20 and €180 per tonne recorded in 2011. The harvestof forestry residues like thinning wood, slash andstumps was oriented at the example of the countrieslike Sweden and Finland, more advanced andexperienced in that area. This information has beencomplemented by information on the forestry in theother European countries and wood chip prices freeforest road. Prices raised are between about €25/odt(oven dry tonne) for low quality residues and €80 to€100 for high quality wood chips.

To make residues available in an economic way also,the harvesting and collection system has to beimproved. A versatile system of a forestry mulchercoupled to a round baler is suggested e.g. in case of

landscape maintenance, clearing of road side green orpower line tracks, and pruning residues. The roughcut, round-baled biomass air-dries in road side stacksand the respective chips cost between €66 and€81/odt, depending on the terrain biomass densityand forwarding distance. Organic wastes frommunicipalities or food processing have a waste yardgate fee of €-60 to €-20 per tonne (€-200/odt at 70%moisture) to cover the costs for composting,depending on the system and purity of the waste;Incineration is typically more expensive. Waste woodhas gate fees typically between €-60 per tonne ofcontaminated or treated wood up to €15 per tonne ofuntreated wood, this is dependent on the region andthe season however. Europe has regions, where themanure from livestock rearing exceeds the amountswhich may be land-spread. In these surplus regionsbetween €5 and €25 per tonne are paid for themanure removal, either to processing plants or toareas of low cattle density.

THERMO-CHEMICAL BIOMASS CONVERSIONThermochemical processes make use of temperatureto decompose organic matter into gaseous, liquid orsolid products. These can be utilised as intermediateenergy carriers for heat, electrical power or fuelsproduction. Thermochemical processes allow for abroad range of feedstocks, making them fuel flexibleand scalable for high conversion capacities. Fortransportation, liquid and solid energy carriers of highenergy density are favourable. Consequently, for theBioBoost value chains complementary thermo-chemical processes have been selected in regard to feedstock type and energy carrier application. From fast pyrolysis, catalytic pyrolysis andhydrothermal carbonisation solid and liquid fuels areobtained, which can be used in different applications.In BioBoost exemplary conversion pathways havebeen agreed making us of different types offeedstocks, producing diverse energy carriers suitablefor different applications (Table 1). In all processes, thefeedstocks selected were converted in pilot plants of

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representative size under optimum conditions. For theproducts obtained in the conversion experimentsconducted, mass yield, energy content and fuelproperties have been determined along with storageand transportation properties including safetyaspects and transportation risks. The energy carrierspecifications relevant for combustion and gasificationwere identified by the industrial partner ENBW.

FAST PYROLYSISThe objective of the tasks on fast pyrolysis was tooptimise the technical setup and operating conditionsof the conversion facilities for pyrolysis of dryfeedstocks towards an energy carrier suitable forgasification and subsequent synthesis to transportationfuels. Besides this reference pathway, the goal was todevelop a flexible pyrolysis process that can providedifferent energy carriers for energetic use helping tointroduce the technology to the market. For thatpurpose separate combustion tests for char and bio-oil are conducted at University of Stuttgart. At KIT, testfacilities for the fast pyrolysis of biogenic residues existon lab-, bench- and pilot-scale. Both the bench-scale(10 kg/h biomass feed) and the pilot scale unit (500kg/h biomass feed) make use of a twin screw mixerreactor (Fig. 3).

Pyrolysis experiments have been conducted with threetypes of biomass, wheat straw, miscanthus and scrapwood. The results from the mass, carbon and energybalances have been set up for all cases. The yield of

slurries (bio-oil plus char) is practically the same forall three biomasses. From 1 kg of a completely driedbiomass, between 0.75 to 0.8 kg of slurry can bederived. However, the chemical properties varystrongly, especially in terms of solid and therewith ashcontent. From wheat straw, having an average ashcontent of ca. 10 wt.%, the slurry with the highest charand ash content (27 wt.% and 11 wt.%) is obtained. Thisslurry contains about 18 wt.% of water and has a higherheating value above 16 MJ/kg. Scrap wood yields theslurry with the highest heating value (above 20 MJ/kg)due to low ash and water contents. For moistfeedstock, the water contents of slurries increases,whereas its solid content and heating value decreases.Thus, the heating values range between 18 MJ/kg and14 MJ/kg, water contents of 25-31 wt.% and solidcontents of 15-25 wt.%.

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Table 1: Conversion pathways addressed in BioBoost

Process Feedstock Energy carrier Application

Fast pyrolysis Straw, miscanthus, scrap wood

Char, bio-oil, pump- andflowable slurry of both bio-oil and char

Separate combustion ofbio-oil and char andgasification (slurry)

Catalytic pyrolysis Beech wood, miscanthus, straw

Low oxygen contentcatalytic bio-oil

Refinery feed to producetransportation fuels

Hydrothermalcarbonisation

Organic municipal waste,spent brewery grain Bio-coal Heat and power

production

Fig. 3 : Reactor of the fast pyrolysis pilot plant at KIT

CATALYTIC PYROLYSISAs the second conversion technology, the catalyticpyrolysis was optimised by CERTH towards theproduction of catalytic bio-oil that has a maximumproduct yield related to the biomass feed capacitywith a minimum oxygen content. This bioenergy carriercan be used for the production of transportation fuelsin an existing refinery infrastructure. The optimisationwork performed in this work aims at optimisedcatalytic materials, suitable feedstock types andprocess operating conditions. GRACE companyperformed the catalyst synthesis and catalyst scale upwhile at CPERI the catalyst pre-screening and theprocess optimisation studies on pilot scale werecarried out. Fifteen new catalytic materials weresynthesised by GRACE and tested at CERTH on benchscale catalytic pyrolysis tests. From this pre-screeningstudy the three best catalysts were selected andscaled up at GRACE in sufficient amounts for pilotscale testing. The new catalysts and five commerciallyavailable catalysts were tested in a pilot plant (Fig. 4)after a steam deactivation procedure. It was concluded

that the best BioBoost catalyst performs better thanthe state of the art commercial catalyst producingabout 1-2 wt.% more oil at the same oxygen yield. Thisresult was fully validated using the other biomassfeedstocks, too. It was concluded that this catalyst isan optimum catalyst for this process. Regarding thefeedstock, the woody biomass turned out to be thebest followed by the energy crop (miscanthus) and theagricultural residue (wheat straw). Regarding processoptimisation the catalyst to biomass ratio (C/B) playsa significant role since with excess catalyst the energycarrier is decomposed and the yield is decreasingagain. The pilot plant has been operated satisfactorywith C/B ratios in the range of 12-20. It was alsoproved that the catalyst deactivation plays animportant role on the catalyst performance. Bothhydrothermal deactivation and ash metal poisoninghave a strong detrimental effect on catalyst stabilityand performance. Sufficient amounts of catalytic bio-oil were produced from the various catalysts andfeedstocks and were fully characterised using routineand advanced characterisation methods like 2DGC-TOFMS. Larger quantities of this carrier were handedover to NESTE company for further downstreamupgrading processes.

HYDROTHERMAL CARBONISATION First, screening experiments on hydrothermalcarbonisation (HTC) with batch micro-autoclaves havebeen performed at KIT to find optimum conversionconditions. Important findings are that the nature ofthe feedstock as well as pre-heating has an importantimpact on the reaction. This and other observationslead to the development of a kinetic model. This modelis able to describe the reaction kinetics of differentbiomass feedstocks. The screening of biomassconversion and the kinetic model lead optimisedoperation of the HTC process at AVA-CO2´s testfacilities (Fig. 5). Here, experiments with breweryspent grains and organic municipal waste in a bench-scale (K3) and industry size (HTC0) reactor wereperformed. Surprisingly, the heating values achievedin these experiments were higher than that in themicro-autoclaves. Therefore, a new laboratory plantwas constructed at KIT; first results show goodaccordance with the results of AVA-CO2. Scale-uptests of AVA-CO2 basically proved the validity of KIT’s

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Fig. 4: Pilot plant for catalytic pyrolysis at CERTH

kinetic model. Regarding the whole process chain frombiomass to end product, there are many parametersand factors which are have to be optimised:

• Nature of biomass, in particular municipal waste:using it untreated would save expensive, additionalcleaning steps, but leads to low heating values andcauses technical problems (blockage of valves,piping etc.); even chopping improves only technicalhandling but not the energetic result.

• Mixing low energetic biomasses, e.g. brewery spentgrains with a low dry matter content with wastestraw (even in mixed forms like in horse dung) offer alarge potential for optimisation of biomass use casesand optimised energetic content of the bio-coal.

• A huge potential for optimisation is on thedownstream side of the HTC process, i.e. separationand drying of the coal and the handling of theprocess water (including recycling).

EXTRACTION OF VALUABLE BY-PRODUCTSIn BioBoost, there is a strong focus on the economicsof the processes. To improve the economics of theoverall value chains the extraction of chemical by-products from the pyrolysis products and the HTCprocess were investigated by DSM in co-operation withother BioBoost partners. For the isolation of mixturesof phenol derivatives (so-called phenolics) CERTH

developed several different extraction schemesdepending on the source of starting material KIT fastpyrolysis oil or CERTH catalytic pyrolysis oils. Whenstarting with fast pyrolysis bio-oil an extraction withan organic solvent yields a final fraction consisting of14.6 wt.% phenolics with 80 % extraction efficiency.The enrichment achieved is satisfying, especiallyconsidering the low concentrations of phenolics in thebio-oil used as feed. Catalytic pyrolysis bio-oil has afar higher concentration of phenolic compounds andmulti-stage processes is developed for their efficientextraction. Experiments at CHIMAR showed that phenolicfractions from pyrolysis oil could be successfully usedin the synthesis of phenol-formaldehyde resins suitablefor the production of plywood panels.

For the isolation of furfurals (HMF, hydroxy -methylfurfural, one of the most important chemicalplatform molecules from biomass) from the aqueousstream of the HTC process two methods wereinvestigated. A first approach is the solvent extractionfor which different solvents were screened on theirpartition coefficients, mutual solubility in the aqueousphase and the physical phase separation properties.Chloroform showed promising extraction propertiesand was successfully tested on a 8-stage mixer settlerbattery. Also, the adsorption of HMF to activatedcharcoal and the following desorption was tested.When optimised towards the production of bio-coal,the amount of furfural in the HTC process water isinsufficiently low for extraction. It was found out, thatfurfurals are the chemical precursors of the bio-coaland therefore are only present in low concentrations,when bio-coal is the target product.

LOGISTICSWithin the BioBoost project optimisation oftransportation and handling of biomass feedstock andof bioenergy intermediates carriers are key issues aspart of the assessment of the whole bioenergy valuechains. The primary focus of the project is onconversion technologies for decentralised conversionof biomass to bioenergy intermediates andsubsequent energy production on a trans-regional,EU-wide level. Transport of biomass over longdistances is relatively expensive; therefore, de-centralconversion plants should be located in regions withlarge feedstock potentials. In BioBoost the viability of

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Fig. 5: Pilot plant for hydrothermal carbonisation at AVA-CO2

decentralised conversion of biomass to intermediatesenergy carriers using optimised transport logisticsfor feedstock and intermediates is investigated onthe basis of regional biomass potentials, data ontransportation modes and costs as well as on data onthe conversion technologies applied. The holisticlogistics model developed by FHOOE simulates andoptimises biomass and energy carrier transportationregarding costs and CO2 emissions as well as suitableidentifies optimal locations for decentralised andcentral plants (Figure 6). Uneconomical transportatione.g. of highly water containing types of biomassresidues featuring low energy contents favour adecentralised supply network which have short pre-haulage distances. The model is used to calculateresulting total costs for given scenarios which describelocations and capacities of de-central conversionplants, as well as the amounts of acquired feedstockand transportation targets.

ASSESSMENTThe assessment methodology and the referencepathways were defined in order to assess the techno-economic, environmental and social aspects ofpre-defined bio-energy carrier reference pathwaysagreed among the BioBoost partners (Fig. 7). Basedon this methodology, a data questionnaire wasdeveloped and completed by all data providers. A firstassessment was completed by TNO for the referencepathways and the results were validated incollaboration partners. Also, it includes the definitionof key performance indicators based on internationaland European frameworks, the data inventory,benchmarks and assessment procedures. Based onthese resources and the data provided by theconsortium partners on logistics, feedstock properties,and conversion technologies, TNO executes theassessment study. The backbone for the BioBoostassessment methodology is the GBEP framework. TheGlobal Bioenergy Partnership (GBEP) developed a setof indicators for policymakers and stakeholders toguide the development of the bioenergy sector and tomeet international goals on sustainable development.These sustainability indicators are science-based andrefer to environmental, social, and economic aspects.They were based on earlier roadmaps on biofuels bythe International Energy Agency (IEA). Practically, thethemes from GBEP were used to identify and evaluatethe Key Performance Indicators (KPI) which are usedto express BioBoost’s assessment results.

Author:Nicolaus Dahmen, BioBoost co-ordinator

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Fig. 6: Concept of the logistics model

Fig. 7: Reference pathways considered in the assessment studies

Wheatstraw Syngas

Beechwood Gasolinediesel

Municipalwaste

Heat andElectricity

Local

plant

Bio-syncrudeCentral

plant

Local

plant

Pyrolysis oilCentral

Local

plant

Bio-coalCentral

Fast Pyrolysis

Catalytic Pyrolysis

Hydrothermal carbonisation

Gasi�cation

plant

Re�nery

plant

Combined Heat & Power

www.bioboost.eu

PROJECT PROFILE Project Acronym: BioBoost (Biomass based energy intermediates Boosting biofuel production) a European collaborative FP7 project funded under contract 282873.Call theme: ENERGY.2011.3.7-1: Development of new or improved sustainable bio-energy carriers.Start: January 2012, duration: 42 months.Budget: €7.3M, funding: €5.1M.Website: www.bioboost.euPartners: 13 Partners from 6 member countries representing chemical industries, energy suppliers, and research companies and institutions:

• Karlsruhe Institute of Technology (KIT) (coordinator), Germany• Center for Research and Technology Hellas (CERTH), Greece• AVA-CO2-Forschung GmbH, Germany• CHIMAR Hellas AE, Greece• ENBW Energie Baden-Württemberg AG, Germany• Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek (TNO); Netherlands• GRACE GmbH & Co. KG, Germany• Instytut Uprawy Nawozenia I Gleboznawstwa, Panstwowy Instytut Badawczy (IUNG), Poland• FHOÖ Forschungs & Entwicklungs GmbH, Austria• Neste Oil Corporation, Finland• SYNCOM Forschungs- und Entwicklungsberatung GmbH, Germany• DSM Chemical Technology R&D BV, Netherlands• University of Stuttgart, Germany