Catalytic gasification of biomass to produce hydrogen rich gas

Abstract Catalytic biomass steam gasification runs were performed in a bench scale plant consisting essentially of a fluidised bed gasifier and a secondary catalytic fixed bed reactor. This secondary reactor employed alternatively two different steam reforming catalysts and calcined dolomite. The operating conditions in the gasifier (temperature, biomass/steam ratio and biomass feed rate) were kept constant for all the runs (770 °C, 1 and 764 kg of biomass per hour per m3 of bed, respectively). The influence of the operating conditions in the catalytic converter on the production of gases, especially H2, was investigated over the temperature range of 660–830 °C, for Gas Hourly Space Velocities (GHSV) in the range 9000–27,700 h−1. About 2 m3 of dry gas (at ambient conditions) per kg of daf biomass were obtained by utilising the fresh catalyst at the highest temperature level, with more than 60% by volume being hydrogen. The lowest tar residue was 0.45 g/kg of daf biomass, which increased slightly over the three hours gasification time. Substantial carbon deposition was observed, mainly on the catalyst layers contacting the inlet gas. On the basis of these results, a process configuration suitable for industrial applications is discussed.