Kinetic study of decomposition of H2S and CH4 for H2 production using detailed mechanism

Abstract

Hydrogen energy has been the subject of increased interest for its high energy density and clean combustion characteristics. Hydrogen sulfide, or its mixture with methane, is considered to be hydrogen-rich fuel and H2 production can be expected from the thermal decomposition process. This paper presented a detailed kinetic mechanism for describing the chemical process during decomposition of H2S-CH4 mixture under dilution condition, with purpose of predicting the H2 production and conversion of H2S and CH4 accurately. Effects of temperature and initial H2S/CH4 ratio on H2 production were experimentally studied using tubular furnace reactor and kinetically analyzed by CHEMKIN software. Conversion rates of H2S and CH4 are promoted by increased temperature, leading to higher production of H2, CS2 but reduced S2 formation. Compared to H2S, CH4 maintains stable at temperature lower than 1000 °C. At temperature higher than 1050 °C, CH4 can react with H2S and S2 to form H2 and CS2 with observable rate. Adjusting the initial H2S-CH4 ratio to be 2 and possibly high temperature are positive factors for maximizing the H2 production efficiency from H2S-CH4 mixture.