The future for biofuels BioenNW, Brussels, 24 September 2015 Tony Bridgwater Bioenergy Research Group European Bioenergy Research Institute Aston University, Birmingham B4 7ET, UK

Thermal conversion for hydrocarbons Primary conversion Fast pyrolysis to bio-oil Gasification to syngas Hydrothermal processing to bio-crude Secondary conversion Fermentation of syngas to ethanol Synthesis of alcohols (MeOH, EtOH etc) from syngas Catalytic cracking bio-oil for deoxygenation Hydrodeoxygenation bio-oil or HTU product Synthesis of hydrocarbons e.g. Fischer Tropsch et al. Tertiary conversion Alcohol dehydration and oligomerisation Refining Refining to specified fuel standards

Routes to biofuels Gasification routes Pyrolysis routes HTP routes Biomass Fast pyrolysis Hydro- thermal processing Bio-oil Gasification Zeolite cracking Syngas Ferment Synthesise Hydro- treating Hydro- treating -OH dehydration Refining Hydrocarbons

Fast pyrolysis Fast pyrolysis requires: High heating rates: Small particle sizes needed Dry biomass: <10wt.% water: Carefully controlled temperature: ~500C Rapid and effective char removal: Char is catalytic Short hot vapour residence time: to avoid product loss reduces liquid yield Atmospheric pressure to minimise char formation The liquid product bio-oil is obtained in yields of up to 75wt.% on dry feed. It has high oxygen, around 25wt.% water and is not miscible with hydrocarbons. Charcoal is consumed in the process..

Decentralised fast pyrolysis Bulk density Biomass density can be as low as 100 kg/m3 Bio-oil density is 1200 kg/m3 Bio-oil liquid storage, handling and transport Tanks and pumps are used No windblown refuse, vermin, or mechanical handling Provides optimum use of loading weight restrictions Central processor e.g. for biofuel 5

Hydrothermal processing Otherwise known as liquefaction, biomass is heated under pressure in a liquid environment at moderate temperatures up to 350C The technology was demonstrated at Albany, Oregon around 1980 with wood in a 1 tph plant. The liquid phase was either water or recycled product oil. Shell subsequently developed their own process - HTU Others have also investigated the technology. The product has much lower oxygen than fast pyrolysis (~15% vs 40%), has high viscosity, and phase separates from the aqueous phase. It is particularly suitable for wet feedstocks.

Bio-oil for biofuels Indirect production Direct production Gasification of bio-oil followed by hydrocarbon or alcohol synthesis. There are many technical and economic advantages of gasification of liquid bio-oil rather than solid biomass; but higher costs for bio-oil Direct production Via catalytic upgrading of liquid or vapour Catalyst can be added to biomass; incorporated into the fluid bed material; use of a close coupled reactor; use of a remote reactor Ex-situ or secondary reaction offers independent control over process conditions; Direct feeding bio-oil into a suitable refinery operation 7

Bio-oil and HTP oil upgrading Zeolite cracking rejects oxygen as CO2 Vapour processing in a close coupled process No hydrogen requirement, no pressure Extensive coking requires burn-off as in FCC Hydro-deoxygenation rejects oxygen as H2O Liquid processing with hydrogen and high pressure Extent of deoxygenation depends on severity of upgrading conditions – pressure, temperature, catalyst and residence time Complex from hydrogen recycling and multiple steps Completion of partial upgrading in conventional refineries is an attractive opportunity for access to economy of scale and expertise.

Gasification methods Gasification is the conversion of organic material into a mixture of CO, H2, CO2, CH4 and impurities of which tar is critical. Type Gas HV % Comments Oxidative Air Oxygen ~5 MJ/Nm3 ~12 MJ/Nm3 Hi Mod Simple but N2 precludes biofuels High cost and high energy use Indirect ~17 MJ/Nm3 Lo More complex. Gas needs compression for biofuels Pressure Air ~10 MJ/Nm3 Higher cost, but higher efficiency O2 for biofuels 9

System requirements - large scale Minimum FT size considered to be viable is 25000 bb/day = 1 mt/y product requiring 5 mt/y biomass Mini-systems under development e.g. Velocys Entrained flow gasifier requires small feed size or liquids. Pretreatment is necessary Grinding biomass has high economic and energy cost Torrefaction gives a brittle feed = higher costs Fast pyrolysis gives a liquid = higher preparation costs Pressure = higher cost; but higher efficiency; Oxygen for nitrogen free gas = high cost + high energy Indirect gasifiers give nitrogen free gas but are not large scale and cannot be pressurised Large scale gives higher efficiency 10

Criteria for evaluation The key criteria for technology and process evaluation are: Development costs including demonstration Biomass availability, cost, logistics, characteristics Product selection Scale of operation Process route complexity and maturity Efficiency of process of biomass to biofuels Capital cost Biofuel production cost Integration into established infrastructure Scaleability Technology risks and uncertainties Current status

BTL energy self sufficiency Energy conversion Mass conversion Self sufficient in heat and power. This costs about 4% in mass yield and 10% in energy yield Process

Capital cost

Capital costs Capital cost, million € 2008 Pyrolysis + large FT Small gasification + small FT Biomass input million dry t/y Capital cost, million € 2008 Large gasification + FT Small FT unproven Small pyrolysis & large FT proven Large gasification unproven

Costs of bio-hydrocarbons Yield, wt% €/t product HHV, GJ/t €/GJ product €/toe Wood feed (daf) 100 67 20 3 145 Pyrolysis oil output 70 147 19 8 331 Diesel (EXCL H2) & 23 592 44 13 578 Diesel (INCL H2 from biomass) & 880 860 Gasoline & 22 453 10 443 FT diesel # 1060 42 25 1030 MTG gasoline # 26 1320 43 31 Crude oil at $100/bbl - 560 15 & Basis: 1000 t/d daf wood feed at 67 €/dry t, 2006 # Basis: 1 mt/y product derived by gasification (DENA report ) 2006

Unit processes and scale Max size TRL Risks Primary conversion Fast pyrolysis to bio-oil 125 t/d 7 Scale up Gasification to syngas 50 t/d Size; gas cleaning Hydrothermal 25 t/d 3 Pressure, Feeding Secondary conversion Fermentation of syngas 1000 t/d Contamination Cat cracking bio-oil 50 kg/d 5 Unproven HDO bio-oil and HTU oil 2 Hydrogen; Unproven Alcohol synthesis 1000 t/d 8 Minimal Hydrocarbon synthesis 200 kbbl/d 9 Tertiary conversion Alcohol dehydration kg/d Refining Refining to standards 100kbbl/d

Conclusions Fast pyrolysis provides a liquid as an energy carrier Gasification has many variants but oxygen and pressure needed for biofuels. Gas clean up is critical. HTU has been demonstrated a long time ago. Increased interest for wet feedstocks. Liquid has higher HV than bio- oil but lower yield. Less developed, more costly. Hydrocarbons via ethanol dehydration offers potentially high yields and a “controlled” product. Process optimisation is essential with integration into established infrastructure Downscaling potential for dispersed biomass but capex increases No current “best” method but criteria are well understood 17

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