Numerical Simulation of Solid Oxide Fuel Cell Tail Gas Catalytic Combustion Based on Three-Way Catalyst

As a clean and efficient advanced power generation equipment, the solid oxide fuel cell (SOFC) has the structural advantages of separation of air and fuel gas, which makes it easy to enrich the CO2 in the tail gas of the fuel side. In order to improve the CO2 concentration in SOFC anode tail gas, a steady-state multi-physical coupled model was established for the commercial three-way catalysts, considering the mass transfer, heat transfer, and chemical reaction processes in the catalytic combustion of SOFC anode tail gas. Based on this model, the catalytic combustion characteristics of SOFC anode tail gas were simulated. The effects of different inlet temperature, reaction space velocities and catalyst sizes on combustion temperature, wall temperature, H2 conversion, CO conversion and outlet CO2 concentration were studied, and the change trend of each parameter was obtained. Based on the existing experiments, the outlet CO2 volume fraction could be increased from 94.72% to 95.33% by optimizing the space velocity, and the outlet CO2 concentration could be increased from 94.72% to 95.64% by optimizing the catalyst size. By analyzing the variation characteristics of outlet CO2 concentration under different working conditions in the catalytic combustion of tail gas, the guidance for the commercial three-way catalyst to be used in the catalytic conversion of anode tail gas and CO2 enrichment in the tail gas of SOFC system was provided.