Proton transfer in SrCeO 3-based oxide with internal reformation under supply of CH 4 and H 2O

Abstract

Mass and charge transfer in a proton-conducting ceramic with internal reformation under the supply of CH 4 + H 2O was experimentally investigated for application to a fuel detritiation system of a fusion reactor. The oxide used in the present experiment was SrCe 0.95Yb 0.05O 3− a , and the electrodes were composed of Ni–SiO 2 paste and Ni wire mesh. The system was described by CH 4 + H 2O∣Ni∣SrCe 0.95Yb 0.05O 3− a ∣NiO∣O 2 + H 2O. Plots of the I– V (electric current density versus cell potential) characteristic curve were determined under the conditions of different H 2O/CH 4 concentration ratios and temperatures of 600–800 °C. It was found that the system could work well even without any external CH 4 reformer. Mass-transfer process in/on the porous Ni electrode and in the ceramic electrolyte was experimentally clarified. The distribution of carbon depositions in the porous electrode was also determined with EDX by scanning over entire surface in the scope of SEM. The ratio of CH 4 to H 2 direct decomposition to its steam-reforming reaction was found to be different from location to location in the porous Ni electrode.