Performance and Optimization of Solid Oxide Fuel Cell Using Low-Concentration Coal Mine Methane

CH₄ concentration of underground drainage coal mine methane is rather low, which is of the explosion risk and difficult to be used. Therefore, a safe and high-efficiency power generation method of low concentration coal mine methane (LC-CMM) was proposed based on the solid oxide fuel cell (SOFC). The deoxygenation and methane enrichment experiment based on the pressure swing adsorption (PSA) was conducted to eliminate the explosion risk of LC-CMM, the large-scale SOFC single cell experiment using the LC-CMM was carried out, and the multi-physics coupling model of SOFC was developed. The results show that the CH₄ concentration can be increased by 1.36 times, the deoxygenation ratio can reach 84.5% through the PSA experiment, and the produced gas can meet the requirement of safe and efficient power generation of SOFC. The power density of large-scale single cell using LC-CMM can reach 110.2 mW/cm², but the anodic carbon deposition occurs after the long-term discharging, thus causing the SOFC performance degradation. The results of numerical simulation show that the decrease of discharging voltage, the increase of volume ratio between O₂ and CH₄ of fuel and the decrease of fuel inlet rate can decrease the carbon deposition, but reducing the power generation performance of SOFC.