Catalytic Internal Reforming, Electrochemical Performance and Thermal Effect of Large-Scale SOFC Single Cell Using Oxygen-Bearing Low-Concentration Coal Mine Methane

Abstract

Coal mine methane is one kind of clean fuel with the global resource quantity of 260×1012 m3, however more than 230×108 m3 low concentration coal mine methane (LC-CMM) is directly emitted to the atmosphere annually in China, causing the severe energy loss and global warming effect. We proposed to utilize the LC-CMM through SOFC for realizing the efficient and clean conversion of LC-CMM. In this paper, the catalytic internal reforming efficiency, electrochemical performance and thermal effect of the large-scale 10cm × 10cm single cell were investigated using the oxygen-bearing LC-CMM as fuel. The results show that the peak power density and open circuit voltage can respectively reach 1.13 V and 100 mW cm-2 using the simulated LC-CMM (12.2 % CH4-4% O2) under 780 oC. Importantly, the stable discharging for nearly 400h using the oxygen-bearing LC-CMM were also be achived based on the large-scale single cell. The CH4 conversion and CO selectivity can also respectively reach 68.5% and 97.9%. The anodic temperature distribution of the large-scale single cell were tested, which implied that the exothermic oxidation reaction happen in the inlet side of anode, causing the higher tempeature of the area. However, the largest temperature gap in the whole large anode is smaller than 5oC, which cannot lead to the thermal distress. Therefore, above experimental results demonstrated the feasibility of efficient oxygen-bearing LC-CMM utilization through SOFC, which might create the opportunity to greatly improve the utilization ratio of LC-CMM and prevent the fuel waste and greenhouse effect by LC-CMM direct emission.