Energy efficient production of hydrogen and syngas from biomass: Development of low-temperature catalytic process for cellulose gasification

The Rh/CeO₂/M (M = SiO₂, Al₂O₃, and ZrO₂) type catalysts with various compositions have been prepared and investigated in the gasification of cellulose, a model compound of biomass, in a fluidized bed reactor at 500-700°C. The conventional nickel and dolomite catalysts have also been investigated. Among the catalysts, Rh/CeO₂/SiO₂ with 35% CeO₂ has been found to be the best catalyst with respect to the carbon conversion to gas and product distribution. The steam addition contributed to the complete conversion of cellulose to gas even at 600°C. Lower steam supply gave the syngas and higher steam supply gave the hydrogen as the major product. Hydrogen and syngas from cellulose or cellulosic biomass gasification are environmentally super clean gaseous fuels for power generation. Moreover, the syngas derived liquid fuels such as methanol, dimethyl ether, and synthetic diesels are also super clean transportation fuels. However, the use of cellulose or cellulosic biomass for energy source through the gasification is challenging because of the formation of tar and char during the gasification process. It is interesting that no tar or char was finally formed in the effluent gas at as low as 500-600°C using Rh/CeO₂/SiO₂(35) catalyst in this process.