(97b) Process Simulation and Comparative Analysis of a Novel 2-Reactor Chemical Looping System for Hydrogen Production Using Biogas

With increasing environmental concerns about greenhouse gas (GHG) emissions from conventional energy sources, there has been a significant shift toward clean combustion sources and carbon-neutral feedstocks. Hydrogen (H2) as a fuel eliminates carbon emissions during energy generation, making it an attractive energy source. Existing processes for producing H2 rely on non-renewable fossil fuels as feedstock. Biogas, derived from the decomposition of waste organic matter, is a renewable and carbon-neutral feedstock that can be utilized for fossil-free H2 generation. In this study, a novel 2-reactor chemical looping water-splitting process (CLWS-2R) is introduced, simulated, and analyzed for the production of H2 from biogas. Process simulations for the CLWS-2R system were conducted to achieve optimized process parameters under desired operating conditions. The evaluation parameters of this scheme were compared with three established processes for H2 production from biogas, including the 3-reactor chemical looping water-splitting (CLWS-3R), steam reforming (SR), and mixed reforming (MR) processes. The simulation results indicate that for a biogas feedstock composition of 25% CO2 by volume, the CLWS-2R system can achieve the highest cold gas efficiency (CGE: 75%) and the highest effective thermal efficiency (ETE: 71%). Sensitivity analysis on biogas composition shows that CLWS-2R achieves its highest ETE with a low CO2 content (25−30 vol%), which is almost equivalent to the ETE obtained using MR. For all biogas compositions with higher CO2 content, MR achieves the highest ETE.