Study of the oxidative methane coupling over SrO-La2O3 catalyst: Experiment and kinetic modeling

Abstract

A 7-step kinetic model of oxidative coupling of methane (OCM) to C2+ hydrocarbons over the SrO-La2O3 catalyst was developed. The experiments were carried out in a fixed bed microcatalytic reactor within a temperature range of 650 to 850 °C. The overall reaction scheme with the minimal number of steps that well predicts experimental data was elucidated via the base of the proposed stoichiometric (molar) analysis of the products formed in the experiments. The reaction network contains three primary and four consecutive reactions, one of them being gas-phase. The rates of each heterogeneous reaction were described by a Langmuir-Hinshelwood type rate equation. Kinetic rate parameters were estimated by fitting to experimental data. The comparison showed that the developed kinetic model predicts experiments well, the average relative deviation between the experimental and simulated data was about 5% and the relative prediction error for all variables amounted to less than 10%. The developed kinetic model was verified by comparing the simulation results with the experimental data obtained over the SrO-La2O3 catalyst and compared with the widely known schemes of OCM reaction proposed by of other authors. A better agreement was observed between the experiments and our model prediction as compared with other models.