Hydrogen-rich syngas production from oxy-steam biomass gasification in a fluidized bed reactor: influence of gasification conditions and bed materials

This study investigates hydrogen-rich syngas production from woody biomass via oxy-steam gasification in a 20 kW fluidized bed reactor. It finds the optimal conditions for gasification by varying the equivalence ratio and steam-to-biomass ratio from 0.19 to 0.38 and 0.5 to 1.3, respectively. Under identified optimal conditions (equivalence ratio of 0.19, steam-to-biomass ratio of 0.7, and temperature of 760 °C), the performance of olivine and silica sand beds was evaluated. The comparison focused primarily on hydrogen production. Additional indicators, including syngas yield, heating value, carbon conversion, gasification efficiency, and tar reduction, were assessed for overall process performance. Olivine bed surpassed sand at identical conditions, producing 38% more hydrogen. These are equivalent to 55 g H2/kgbiomass for olivine, with a lower heating value of 10.5 MJ/kg, compared to 40 g H2/kgbiomass for sand, with a lower heating value of 9.6 MJ/kg. In addition, olivine exhibited superior tar reduction efficiency (52%) compared to sand. Our findings provide useful information for optimal bed material selection to maximize hydrogen production in biomass oxy-steam gasification fluidized bed systems.