Design and comparisons of three biomass based hydrogen generation systems with chemical looping process

•Three chemical looping systems are proposed for biomass based hydrogen generation.•The CO2 discharge is minimized with the utilization of both CLG and CLP technologies.•The cold gas efficiencies of Systems A, B and C are 72, 54 and 60%, respectively.•The values of Rhtb of Systems A, B and C are 0.73, 0.66, and 0.76 Nm3/kg.•The values of Rcs of Systems A, B and C are found to be 92, 95 and 96%.

The technology of hydrogen generation from biomass has attracted more and more attentions nowadays. In this work, three biomass-based chemical looping hydrogen generation systems, Systems A, B and C, are comprehensively studied. System A is mainly composed of biomass hydrogasification, methane reformation and the calcium-looping based CO2 absorption. System B is mainly composed of biomass steam gasification and Fe2O3/FeO-looping based hydrogen generation circulation. System C is mainly composed of biomass steam gasification and Fe3O4/FeO-looping based hydrogen generation circulation. The three systems are modeled and their characteristics are analyzed and compared thermodynamically. System A has the highest cold gas efficiency (CGE) which is 72%; System B has the lowest CGE of 54% but it can generate additional nitrogen as byproduct; System C has the highest hydrogen generation ratio and its CGE is moderate and is 60%. The carbon dioxide sequestration rates of the three systems are all above 90%.