Detailed kinetic modeling of H₂S formation during fuel-rich combustion of pulverized coal

Abstract

The paper presents a detailed kinetic study on H2S formation during fuel-rich combustion of pulverized coal via tube furnace experiment and kinetic analysis with Chemkin. A new detailed kinetic model involving 34 species and 115 reactions was developed, with emphasis on CS2 as a source for H2S. The novel model was validated using experimental data with respect to the concentration distributions of H2, CO, H2O, CO2, SO2, H2S, COS and CS2. Sensitivity analysis shows that H2S concentration was very sensitive to reactions (2) H2S + H = SH + H2, (89) SO2 + CO = SO + CO2, (104) COS + H2O = H2S + CO2, (62) HOSO (+M) = H + SO2 (+M), (103) CS2 + H2O = H2S + COS, etc. Also, SH, S, and SO were the key free radicals for H2S production. Rate of production analysis (ROP) were also performed, which indicate that SH was the most important precursor of H2S. Based on the detailed kinetic model and ROP analysis, the simplified reaction path of H2S formation was constructed. Finally, the new model was compared with the Leeds University sulfur chemistry model. The two models have the same key free radicals and four major elementary reactions. The main difference is that CS2 was a notable source for H2S in our model targeted for coal combustion, and should be given special attention.