The analyses of the start-up process of a planar, anode-supported solid oxide fuel cell using three different start-up procedures

Three start-up procedures for an anode-supported planar SOFC are proposed and investigated numerically in the present study. The first is to introduce the inlet fuel at the operation temperature after the heat-up process is completed. The second is to incorporate the anode-recycling mechanism into the start-up process. The third is to fix the difference between the inlet-fuel temperature and the cell minimum temperature. The numerical results obtained from the present study show that the effective maximum absolute temperature-gradient is exhibited in the early stage of the start-up process. For the present investigated SOFC configuration, the required start-up time for the case using methane is 3.2-fold longer than that using hydrogen. The effective maximum absolute temperature-gradient for the case using hydrogen is 2.2-fold larger than that utilizing methane. The endothermic internal reforming reaction of methane has a positive effect on the accommodation of the temperature uniformity during the start-up process. The anode-recycling mechanism significantly reduces the start-up time For the fixed-temperature-difference start-up procedure, a properly selected temperature difference may lead to a smaller effective maximum absolute temperature-gradient in the early stage and a shorter start-up time by accelerating the start-up pace in the later stage. (C) 2012 Elsevier B.V. All rights reserved.