Influence of Experimental Conditions on Reliability of Carbon Tolerance Studies on Ni/YSZ SOFC Anodes Operated with Methane

摘要

The effect of experimental parameters on carbon accumulation in the Ni/YSZ anode of SOFC operated at 1,073 K with CH_4, has been described in this paper. Experimental parameters including sealing of the cell to the cell holder, operating current, surface coverage by current collector paste on the surface of the anode, and the configuration of the current collector were evaluated in terms of carbon accumulation at the Ni/YSZ anode. The carbon accumulation was quantified using temperature-programmed oxidation and cells were examined using scanning electron microscopy. The results suggested that variations in any of these experimental parameters could significantly increase or decrease the amount of carbon accumulation on Ni/YSZ anodes, and hence, the reliability of the carbon tolerance studies. In particular, the higher the air leakage rate, the less carbon that accumulated on equivalent anodes. The extent of surface coverage by current collector paste and the configuration of current collector also impacted the amount of carbon accumulation. Less carbon accumulated directly below and near the areas of current collector paste than on the anode areas directly exposed to CH_4 and far from the current collector paste. Additionally, variations in the fuel humidity and current levels also significantly influenced the carbon accumulation.