Thermal modelling of ethanol-fuelled Solid Oxide Fuel Cells

Abstract

A 2D thermal model is developed to investigate an ethanol-fuelled Solid Oxide Fuel Cells (E-SOFC) with a Ni-ZrO2/CeO2 functional layer for internal reforming of ethanol. The catalytic kinetics of the functional layer used in this model is validated in terms of ethanol conversion and product selectivity in the experimental data of a fixed-bed testing reactor. The simulated E-SOFC demonstrates a typical performance of 4385.6 A m−2 at 0.6 V, corresponding to a power density of 2631.4 W m−2, with a high conversion ratio of ethanol (0.903) at 700 °C. Parametric studies of voltage, water to ethanol ratio and inlet fuel gas temperature are conducted and comprehensively analysed, concluding that the positive effects of lowering the voltage and increasing the inlet temperature on the ethanol conversion. We find that adding the reforming layer is a facile and effective way to replace the conventional H2 by abundant-in-nature ethanol for SOFC from the numerical analysis. Attention is also drawn to the carbon deposition risk by thermodynamic analysis of the gas composition, suggesting to keep the water to ethanol ratio higher than 3. The as-developed model can serve as an effective tool for the optimization of the operating conditions and geometry design to avoid carbon deposition and improve the performance of ethanol-fuelled Solid Oxide Fuel Cells.