CATALYTIC COMBUSTION OF METHANE

Palladium-based catalysts have been found to be the most efficient catalysts for the catalytic oxidation of methane to carbon dioxide and water. The catalytic oxidation is dependent on factors such as the oxygen:methane feed ratio, the loading of precious metal on the support, the nature of the support, the particle size of the precious metal and the extent and nature of catalyst pretreatment. The reaction rate is found to be dependent on methane concentration, generally to the first order or less. The dependence of rate on oxygen pressure is found to depend on the operating conditions. Because of overheating as a result of high conversions of methane, chemical kinetics are often affected by mass and heat transfer. Deactivation of the catalyst can involve sintering or poisoning. The thermal stability of the catalyst is strongly dependent on the support and the extent of overheating induced by oxidation of methane. Sulphur oxides deactivate most noble metal catalysts with the exception of platinum.