Safe operating conditions of low concentration coal mine gas fed SOFC with water effect: thermodynamic and kinetic modeling

Large amounts of low concentration-coal mine gas (LC-CMG) are directly emitted, causing severe greenhouse effect and energy waste. Solid oxide fuel cell (SOFC) has been proved to be the clean and efficient utilization method of LC-CMG, however the risks of coking, nickel oxidation and explosion greatly threat the operation of SOFC using LC-CMG. Thereby, a thermodynamic model and a two-dimensional kinetic multi-physics model were established to determine the suitable operating parameter range. Besides, the effects of parameter were studied with different water contents by the kinetic model. The results indicate that safe range of fuel components expand with increasing temperature and water contents. The suitable temperature, over-potential and CH 4 /O 2 ratio ranges with (0/3/10 %) H 2 O in fuel are respectively 730–800 °C, 0.2V, 1.3–2/1.5–2.4/1.7–4, which can greatly expand with the increase of water content. This work can guide the operation condition optimization to guarantee the safe and stable running of LC-CMG fed SOFC. • Risk estimation models of LC-CMG fed SOFC are built based on thermodynamic and kinetic theories. • Effects of operating parameters on coking, oxidation and H 2 production rates are analyzed. • Safe ranges of operation parameters with different water contents are distinguished.