Monte Carlo simulation is applied to study the partial oxidation of methane over a nickel catalyst. Base on the Langmuir-Hinshelwood mechanism, the kinetic behavior of this reaction is analyzed and the results are compared with previous experiments. This reaction exhibits irreversible phase transitions from reactive regions with sustained reaction to poisoned regions without reaction. The fractional coverage of the adsorbed species and the production rate of H2, CO, H2O, and CO2 are evaluated at steady state as functions of feed concentration of the methane and oxygen, and reaction temperature. The simulation results are in good agreement with experimental observations. The effect of diffusion of adsorbed species and inactive impurities on the surface is also studied. It is observed that the diffusion of adsorbed species slightly changes the reactive range of the feed concentration and temperature, increasing the reactive range as diffusion rate increases. Only the diffusion of adsorbed H and O on the surface is important; the diffusion of the other species plays little role in the reaction. With the increase in impurities on the surface, the reaction rate decreases and the reaction ceases at a certain point. Moreover, the discontinuous first-order phase transition converts into a continuous second-order phase transition due to impurities.

Partial oxidation of methane on a nickel catalyst: Monte Carlo simulation study

251st National Meeting (2016)

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