4.3.6. Gasification for synfuelsA recent concept that has attracted much interest is thedecentralised production of bio-oil or bio-oil-char slurries fortransportation to a central process plant for gasification andsynthesis of hydrocarbon transport fuels, by for exampleFischer Tropsch synthesis, or alcohols. This is depicted abovein Fig. 10. Although there is a small energy penalty from thelower pyrolysis energy efficiency, transportation energy andadditional bio-oil gasification stage, this is more thancompensated by the economies of scale achievable ona commercial sized gasification and transport fuel synthesisplant [187].Although the concept of very large gasification plants of5 GW or more has been promoted [188] based on importationof biomass on a massive scale to an integrated plant, based forexample at Rotterdam, there are significant obstacles to beovercome. Decentralised fast pyrolysis plants of up to100,000 t/y or 12 t/h are currently feasible and close to beingcommercially realised. Bio-oil gasification in an entrainedflow oxygen blown pressurise gasifier is also feasible such asa Texaco or Shell system, with the added advantage thatfeeding a liquid at pressure is easier than solid biomass, offers
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