The oxidative coupling of methane (OCM) reaction system was investigated in a packed-bed membrane reactor (PBMR) numerically via a comprehensive computational fluid dynamics (CFD) study. In this context, the complete set of momentum, mass, and energy balances were solved through finite-volume method in cylindrical coordinate system. The fractional-step method was utilized to decouple the reaction source terms from the convection-diffusion terms. The general observed trends for variation of the components’ concentrations along the bed were successfully explained by analyzing the rate of reactions. In this study, the effect of membrane thermal conductivity, and oxygen permeation were also examined which can affect the OCM reactor and process performance significantly. Finally, the dynamics behavior of the system was studied and by following the reaction rates and the shift of reactions along the catalytic-bed and with time, the reaction mechanisms were discerned. The results of the performed CFD simulation can be used as a baseline for a possible optimization approach for OCM reactor performance improvement.

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The effect of operating conditions and feed characteristics on the performance of the oxidative coupling of methane (OCM) reactor was investigated numerically by analyzing the concentration of the reactants and products along the fluidized-bed reactor. Aimed at modeling such multiphase flow, a two-fluid model based on the kinetic theory of granular flow was applied. The impact of the kinetic model was conceptually investigated through investigation of the observed reaction pathways along the reactor under various feed dilutions. The overall predicted selectivity toward ethylene and ethane (C2-products) and methane conversion were in agreement with the experimental data. In detail, the results of simulations demonstrated that the fast acceleration of ethylene steam reforming at T > 800 °C results in C2 selectivity peaking around T = 800 °C. However, an increase in pressure from 1 bar to 3 bar slightly decreases the C2 selectivity. At identical space velocity, a decrease in CH4/O2 ratio improves the C2 yield.