Kinetic study of oxidative coupling of methane over Mn and/or W promoted Na2SO4/SiO2 catalysts

A comprehensive kinetic model for oxidative coupling of methane (OCM) over Mn and/or W promoted Na2SO4/SiO2 catalysts was developed based on a micro-catalytic reactor data. The methane conversion and ethylene, ethane, carbon monoxide and carbon dioxide selectivities were obtained in a wide operating condition range of 750-825 °C, CH4/O2 = 2.5-10 and contact time = 267-472 kg·s·m−3. Reaction networks of six models with different rate equation types were compared together. The kinetic rate parameters of each reaction network were estimated using linear regression or genetic algorithm optimization method (GA). A reaction network suggested by Stansch et al. for OCM was found to be the best one and was further used in this work. The suggested model could predict the experimental results of OCM reaction within a deviation range of ±20%.