CATALYTIC GASIFICATION OF BIOMASS TO PRODUCE HYDROGEN-RICH GAS

Catalytic biomass steam gasification runs were performed in a bench sc ale plant consisting essentially of a fluidised bed gasifier and a sec ondary catalytic fixed bed reactor. This secondary reactor employed al ternatively two different steam reforming catalysts and calcined dolom ite. The operating conditions in the gasifier (temperature, biomass/st eam ratio and biomass feed rate) were kept constant for all the runs ( 770 degrees C, 1 and 764 kg of biomass per hour per m(3) of bed, respe ctively). The influence of the operating conditions in the catalytic c onverter on the production of gases, especially H-2, was investigated over the temperature range of 660-830 degrees C, for Gas Hourly Space Velocities (GHSV) in the range 9000-27,700 h(-1). About 2 m(3) of dry gas (at ambient conditions) per kg of daf biomass were obtained by uti lising the fresh catalyst at the highest temperature level, with more than 60% by volume being hydrogen. The lowest tar residue was 0.45 g/k g of daf biomass, which increased slightly over the three hours gasifi cation time. Substantial carbon deposition was observed, mainly on the catalyst layers contacting the inlet gas. On the basis of these resul ts, a process configuration suitable for industrial applications is di scussed. (C) 1998 International Association for Hydrogen Energy.