An investigation of fuel composition and flow-rate effects in a H ₂S fuelled sofc: Experiments and thermodynamic analysis

Hydrogen sulphide (H ₂S)-fuelled solid oxide fuel cells (SOFCs) can potentially generate useful electrical energy while disposing of H ₂S, a toxic by-product of the fossil fuel industry, on site. Experimental results from H ₂S fuelled SOFCs exhibit characteristics, for example, an unusual dependence of cell performance on fuel composition and flow-rate, which are poorly explained in the literature. In this work we: (a) present results for experiments where the composition and flow-rates were varied for both the fuel and oxidant streams to analyse their effect on fuel cell performance, and (b) develop and use a thermodynamic analysis to help understand these experimental results. Through this work, we shed further light on two basic questions unanswered so far, (1) Why does the flow-rate of the fuel affect the open circuit potential of the fuel cell? (2) Which of the chemical species present in the fuel is oxidised on the anode? Our experiments and analysis suggest that H ₂S, and not H ₂ produced from H ₂S dissociation, is preferentially electro-oxidised on the anode in our experiments.