Experimental Studies on the Influence of H_2S on Solid Oxide Fuel Cell Performance at 800℃

摘要

Short-term tests showing the influence sulfur has on solid oxide fuel cell (SOFC) performance have been performed. The experiments were performed using two single-cell SOFC setups operated at 800℃. In setup I, sulfur (H_2S) was mixed into the fuel gas in concentrations ranging from 20 to 100 ppm. It was found that the performance decreased with increasing sulfur concentration up to 80 ppm. The performance loss at 80 and 100 ppm sulfur was equal. At a current density of 200 mA cm~(-2), the operating voltage was reduced from 0.810 V at 0 ppm H_2S to 0.790 V at 100 ppm H_2S, corresponding to an increase in the area-specific cell resistivity (ASR) of 0.10 Ω cm~2. In setup Ⅱ, sulfur levels of 80, 120, and 240 ppm were introduced. In all these three cases the ASR increased by around 0.13 Ω cm~2. Removing the sulfur impurity when the 240 ppm H_2S exposure test was finished the cell performance fully recovered, indicating no irreversible changes in the cell structure.