Partial oxidation ofmethane to synthesis gas over Rh/a-Ah03 at high temperatures

The partial oxidation of methane to synthesis gas has been studied in a continuous flow reactor using a Rhla-Ah03 catalyst under conditions as close as possible to those industrially relevant: pressures up to 800 kPa and temperatures higher than 1274 Kin order to avoid the formation of carbon and to obtain high equilibrium selectivities to CO and H2. Intrinsic kinetic data were obtained when the feed was diluted with helium. Gas-phase reactions were found to occur at 500 kPa when the feed was not diluted. A reaction network has been derived from experimental results in which oxygenconversions range from 0 to 1. CO2,yilt; and H20 are the primary products. C2H. is formed by oxidative dehydrogenation ofYH6. CO and H2 are formed by reforming ofCH. by C02 and H20; an additional direct route to CO and H2 at low oxygen conversions cannot be excluded. The catalyst appears to be present in two states, the transition being at an oxygen conversion of0.4 under the conditions used. The support probably enhances oxidation reactions by reverse spillover of oxygen or hydroxyl species onto rhodium. The support as such behaves similarly to the catalyst at low oxygenconversions, but shows no reforming activity