Catalytic ignition of methane/oxygen mixtures over platinum surfaces: comparison of detailed simulations and experiments

The surface ignition of methane/oxygen/nitrogen mixtures over a platinum foil is modeled at atmospheric pressure with a revised detailed surface kinetics mechanism including 20 surface reactions and seven surface species, detailed gas-phase kinetics and simplified multicomponent transport. Simulation results are compared to experimental data from the literature and very good agreement is found. Sensitivity analysis shows that the dissociative adsorption of molecular oxygen and the decomposition of methane are the most important steps in affecting the catalyst ignition. Comparison with experiments and sensitivity analysis indicate that methane adsorption is activated, and contrary to previous suggestions, partial equilibrium in adsorption/desorption steps breaks down. In addition, prior to ignition the adsorption of reactants is competitive and combustion products are favored as compared to syngas. Finally, results are compared to hydrogen/air mixtures. (C) 1997 Elsevier Science B.V.