Partial Oxidation of Methane on a Nickel Catalyst: Kinetic Monte-Carlo Simulation Study

摘要

Kinetic Monte-Carlo simulation is applied to study the partial oxidation ofmethane over a nickel catalyst. Based on the Langmuir-Hinshelwood mechanism,the kinetic behavior of this reaction is analyzed and the results are comparedwith previous experiments. This system exhibits kinetic phase transitionsbetween reactive regions with sustained reaction and poisoned regions withoutreaction. The fractional coverages of the adsorbed species and the productionrates of H2, CO, H2O, and CO2 are evaluated at steady state as functions offeed concentration of the methane and oxygen, and reaction temperature. Theinfluence of lattice coordination number, diffusion, and impurities on thesurface is investigated. The simulation results are in good agreement with theexperimental studies where such results are available. It is observed that whenthe lattice coordination number is increased to eight, the width of thereactive region increases significantly. Moreover, the phase transition becomescontinuous. The diffusion of adsorbed O and H on the surface plays a measurablerole in the reaction, increasing the maximum production rates as the diffusionrate increases. In systems with impurities, the production rates are greatlyreduced and the phase transition is also changed from being abrupt tocontinuous.