High-rate electrochemical partial oxidation of methane in solid oxide fuel cells

This paper describes results on direct-methane solid oxide fuel cell (air, LSM-YSZYSZNi-YSZ, CH4) operation for combined electricity and syngas production. Thermodynamic equilibrium predictions showed that efficient methane conversion to syngas is expected for SOFC operating temperature >700 °C and O2−/CH4 ratios of ≈1. A simple thermal analysis was used to determine conditions where the cell produces enough heat to self-sustain its operating temperature; relatively low cell voltage and O2−/CH4 ratios > 1 were found to be useful. Fuel cells operated at T ≈ 750 °C, V ≈ 0.4 V, and O2−/CH4 ≈ 1.2 yielded electrical power output of ~0.7 W cm−2 and syngas production rates of ~20 sccm cm−2. Stable cell operation without coking for >300 h was achieved.