Effect of sulfur on the cell performance in a molten carbonate fuel cell

This study evaluated the performance characteristics of a molten carbonate fuel cell (MCFC) under sulfur poisoning condition. A 100 cm ² bench-scale MCFC was used for the performance test. The performance of the cell at the normal operation condition was measured at 620 °C under atmospheric pressure. To evaluate the sulfur poisoning effect, 50 ppm H ₂ S/Balanced N ₂ gas mixture at a flow rate of 30 ml/min was injected into the anode. The cell performance was analyzed via steady-state polarization (SSP) and inert gas step addition (ISA) methods. The overpotential of the cell was observed to have been changed by the injection of H ₂ S gas, and an overpotential increase of ca. 40% was recorded after about 100 hours from the point of addition of the H ₂ S gas. A voltage reduction rate of −2.62×10 ⁻⁴ mV/s was recorded at a current density of 150mA/cm ² after about 240 hours. The steady-state polarization characteristics of the cell showed that the sulfur poisoning was relatively slow. In addition, the effect of H ₂ S gas on the cell performance was quantitatively measured by the ISA method.