年間 8 号発行
ISSN 印刷: 2150-3621
ISSN オンライン: 2150-363X
Indexed in
CH4, H2S, AND SO2 OXIDATION ON Pt CATALYSTS
要約
The kinetic parameters of the lean oxidation of CH4, H2S, and SO2 on a Pt foil and on Pt/Al2O3 and Pt/CeO2/Al2O3 catalysts were derived in a stagnation point flow reactor under atmospheric pressure and at temperatures up to 900 °C. Kinetic mechanisms were devised using a novel methodology. Doping the N2-diluted CH4-air reactant flow with H2S and SO2 concentrations had a significant promotional effect on the methane combustion rate for all Pt catalysts tested. At the temperatures tested, alumina and alumina-ceria supports oxidized only H2S to SO2, showing no net conversion of CH4 to CO2 or of SO2 to SO3. In contrast, Pt foil and the supported Pt were good catalysts of CH4, H2S, and SO2 oxidation. A temperature window of conversion of SO2 to SO3 on the Pt/Al2O3 catalyst was observed. This window could be used in SOx removal techniques of combustion exhausts. One-step and two-step chemical reaction mechanisms were devised for the CH4 and SO2 oxidations, respectively. The conversion of H2S and its selectivity to SO2 and SO3 on the Pt-alumina catalysts were accurately reproduced using a three-step mechanism.