Exploration of the possibilities for production of Fischer Tropsch liquids and power via biomass gasification

This paper reviews the technical feasibility and economics of biomass integrated gasification–Fischer Tropsch (BIG-FT) processes in general, identifies most promising system configurations and identifies key R&D issues essential for the commercialisation of BIG-FT technology. The FT synthesis produces hydrocarbons of different length from a gas mixture of H2 and CO. The large hydrocarbons can be hydrocracked to form mainly diesel of excellent quality. The fraction of short hydrocarbons is used in a combined cycle with the remainder of the syngas. Overall LHV energy efficiencies,1 calculated with the flowsheet modelling tool Aspenplus, are 33–40% for atmospheric gasification systems and 42–50% for pressurised gasification systems. Investment costs of such systems (367 MWth) are MUS$ 280–450,2 depending on the system configuration. In the short term, production costs of FT-liquids will be about US$ 16/GJ. In the longer term, with large-scale production, higher CO conversion and higher C5+ selectivity in the FT process, production costs of FT-liquids could drop to US$ 9/GJ. These perspectives for this route and use of biomass-derived FT-fuels in the transport sector are promising. Research and development should be aimed at the development of large-scale (pressurised) biomass gasification-based systems and special attention must be given to the gas cleaning section.