Thermal conversion efficiency of producing hydrogen enriched synthesis gas from steam biomass gasification

The purpose of this work was to investigate the production of hydrogen enriched syngas through cellulosic biomass gasification. Of particular interest was the thermodynamic conversion of energy to hydrogen. To determine this, a custom 100 kWthermal uidized bed steam gasification system was constructed. An experimental study was performed to determine the effects of the major gasification parameters on the thermal conversion efficiency. The maximum conversion of biomass heating potential to syngas heat content (m × heating value) was 68% which occurred at low steam to biomass ratios by weight (<1). The maximum conversion of energy to hydrogen heat content was 29%, which occurred at a relatively high steam to biomass ratio ( >3). It is suggested that catalytic shift reformers be utilized to convert methane and carbon monoxide into hydrogen. Further analysis revealed that to produce syngas with high hydrogen concentration, inert- uidized gasification was the most efficient method tested in this study. While uidized bed gasification with CaO was found to be less efficient than inert-bed gasification, it does not require catalytic shift reactors to upgrade the hydrogen concentration. The research presented in this dissertation provides new information on gasifier operating conditions that can serve as a crucial tool to aid in the design of a working gasification plant whose goal is to produce hydrogen.