Testing of Large Format Lower Temperature SOFCs and Stacks with Hydrocarbon Fuels
In this work, results will be presented from single cell and short stack testing using reformate mixtures consisting of CH4, H2, CO, CO2, and steam. Tests utilized large format (approximately 10 cm by 10 cm) cells based on GDC electrolytes with an active area of ~80 cm2. Current-voltage characteristics and impedance spectroscopy data were collected at various currents using electronic load and potentiostat/FRA equipment. Additionally, gas compositions in the fuel exhaust stream were determined using gas chromatography.
Initial results at 650 °C showed a single cell power of ~53 W running on hydrogen and ~51 W running on 100% reformate slip (~21% CH4). Long term test results using a constant applied load of 18 A for a 2 cell short stack showed no evidence of coking even when run on 50% CH4/50% H2O for ~50 hours and 97% CH4/3% H2O for ~150 hours. Additional long term test results will be presented along with a study on degradation.