Achieving Autothermal Operation in Internally Reformed Solid Oxide Fuel Cells:  Simulation Studies

An integrated (or indirect) internal reforming solid oxide fuel cell (IIR-SOFC), in which the reformer is in good thermal contact with the SOFC, is a desirable mode of operation and leads to increased overall efficiency. However, the mismatch in the rates of the two reactions can lead to undesirable local cooling (and hence unacceptable thermal stresses) at one point or another within the SOFC system. In this work, we use simulation studies to investigate ways to avoid this difficulty and to achieve stable autothermal operation. Methods that have been shown to be of potential use include the use of lower activity catalysts such as washcoats on the wall of the reformer; the use of diffusion barriers, which can provide a catalyst activity profile along the length of the reformer; and the coupling of partial oxidation along with the steam reforming of the methane used as raw fuel. Experimental studies have been carried out in parallel with the simulation studies to test the practicality of implementing these ideas.