Controlling reformation rate for a more uniform temperature distribution in an internal methane steam reforming solid oxide fuel cell

Abstract

Internal methane reformation capability makes the SOFC technology favorable for integration with the existing infrastructure. Methane steam reformation (MSR) reaction happening at the entrance of the fuel channel is endothermic while exothermic fuel cell reactions dominate the remaining of the cell. Consequently cold spots occur near the inlet while hot spots occur farther down the electrode resulting in steep temperature gradients. To alleviate this problem, it is suggested that MSR reaction can be slowed down to extend methane conversion to a broader fuel cell region. Rejecting the heat released during the fuel cell reaction with MSR, temperature gradients can be flattened for a more uniform distribution. In this study a three dimensional computational fluid dynamics model is developed to investigate the potentials of controlling the MSR rate for improved thermal characteristics of an SOFC. Modification of the catalytic activity by changing anode material and microstructure is considered as the means of controlling reaction rate. Also the effect of fuel stoichiometry and interconnect material on the thermal gradients are analyzed. It is suggested that the anode material can be engineered to have a more balanced temperature distribution and relaxed thermal stresses during methane fueled SOFC operation.