Biomass direct chemical looping process: Process simulation

Biomass is a clean and renewable energy source. The efficiency for biomass conversion using conventional fuel conversion techniques, however, is constrained by the relatively low energy density and high moisture content of biomass. This study presents the biomass direct chemical looping (BDCL) process, an alternative process, which has the potential to thermochemically convert biomass to hydrogen and/or electricity with high efficiency. Process simulation and analysis are conducted to illustrate the individual reactor performance and the overall mass and energy management scheme of the BDCL process. A multistage model is developed based on ASPEN Plus (R) to account for the performance of the moving bed reactors considering the reaction equilibriums. The optimum operating conditions for the reactors are also determined. Process simulation utilizing ASPEN Plus (R) is then performed based on the reactor performance data obtained from the multistage model. The simulation results indicate that the BDCL process is significantly more efficient than conventional biomass conversion processes. Moreover, concentrated CO2, produced from the BDCL process is readily sequesterable, making the process carbon negative. Several BDCL configurations are investigated for process optimization purposes. The fates of contaminants are also examined. (C) 2010 Elsevier Ltd. All rights reserved.