Towards feasible temperature management and thermo-mechanical stability of carbon-assisted solid oxide electrolysis cell

Abstract

Carbon assisted solid oxide electrolysis cell (CA-SOEC) owns advantages of fast electrolysis rate, low operating cost and product flexibility. But the endothermic carbon gasification reaction leads to a steep temperature gradient in the anode, thus causing extra thermo-mechanical stress and inhibits long-term operation. Herein, we propose a new CA-SOEC using metal foam in the anode chamber and develop 2D numerical models to evaluate the fluid-dynamic/thermal/chemical/electrochemical/mechanical characteristics of the new cell. It is found that the use of metal foam can significantly enhance the heat transfer process and achieve an even temperature distribution in the CA-SOEC, where the peak temperature difference can be decreased from 57.0 to 21.5 K. As a result, the maximum thermo-mechanical stress is decreased by 69.9 % with the adoption of metal foam. Through further analyses of inlet gas flow rate, inlet gas temperature and the distance between anode chamber and electrode, we find that a small distance and a large flow rate are beneficial for optimizing the temperature distribution. The results of the study provide useful information for the structure optimization of solid oxide cells using carbon fuels.