Stability of the Ni-base Anode for Hydrocarbon Fuels Containing Sulfur

摘要

Cell operation tests with hydrocarbon fuels reformed on the anode were carried out at 800 °C for a SOFC with scandia stabilized zirconia (ScSZ) electrolyte and nickel - ScSZ (Ni-ScSZ) cermet anode. Hydrocarbons of n-dodecane (paraffin type C_(12)H_(26), model fuel of kerosene) and desulfurlized (low sulfur content) kerosene were fed to the anode at S/C = 2. Continuous operation could not be achieved with the kerosene fuel and the anode completely detached from the electrolyte after the cell test. Nickel particles grew more than 3 micrometer in diameter after the kerosene test, whereas particle growth was about 1 micrometer after the n-dodecane test. The nickel sintering seems to be enhanced by remaining sulfur compounds and/or aromatic hydrocarbons in the kerosene. From thermodynamic consideration, formation of Ni-S eutectics was examined under the SOFC operation conditions.^