Internal Conversion in the Membrane-Supported SOFC

Abstract

Studies of the internal methane conversion process were carried out on an experimental short stack of two 100x100 mm electrolyte-supported SOFCs. A whole series of experiments were carried out on H2+CH4+H2O mixtures with different sets of conditions – an increase in the ratio and consumption of methane, and then a decrease in temperature. The results of experiments at an operating temperature of 850°C showed that the kinetics of internal conversion was largely underestimated. The assembly of two SOFCs converts methane up to concentrations not exceeding the calculated equilibrium ones, up to the maximum available flow rate on the equipment used – 187 ml/min – even without current passing. This fuel flow rate can provide a current of up to 53 A, while the rated operating current of these SOFCs is about 20 A, up to 30 A on methane-rich fuel. The current further stimulates the conversion by generating additional steam.