A kinetic model for the oxidative coupling of methane over Na2WO4/Mn/SiO2

Abstract

A kinetic model of the oxidative coupling of methane was developed by considering ethane, ethylene, carbon monoxide, and carbon dioxide production in such a way that the reactor was designed for the reactions to take place in the catalyst-loading region as much as possible. The effectiveness of the reactor specification was validated by low conversion of methane in the blank test. A mechanism for catalytic reactions on the surface of Na2WO4/Mn/SiO2 gel and gas-phase radical reactions was suggested based on a literature survey. Reaction rates were developed by applying rapid equilibrium for adsorption and the quasi steady state approximation to the intermediate on the catalytic surface. Kinetic parameters were estimated by fitting experimental data with temperature, space velocity, and CH4/O-2 ratio varied in full factorial manner. The validity of the model was corroborated by comparing its simulated results with experimental data. The effectiveness of the estimated parameters was discussed with respect to reported values. The effects of operating conditions were assessed using the developed model. (C) 2012 Elsevier B.V. All rights reserved.