Positive and negative catalytic effects of a nickel mesh catalyst for the partial oxidation of ethane

The catalytic reactions between O2 and hydrocarbons are an important class of reactions in energy and chemical industries. This study aims to investigate the complicated reactions involving reactive radicals on the catalyst surface and in the gas phase during the partial oxidation/combustion of light alkanes. In order to avoid intra-particle transport constraints associated with the traditional porous catalysts, a non-porous nickel mesh catalyst has been used in this study for the partial oxidation of ethane with O2 at 625 °C at atmospheric pressure. The catalytic effects of the nickel mesh strongly depended on the flow rate of gas reactants passing through the mesh. At a low gas flow rate, the nickel mesh catalyst showed negative effects for the oxidation of ethane. At a high gas flow rate, the same catalyst showed positive catalytic effects. Our results can be explained by considering the selective/preferential adsorption and desorption of different radicals onto and from the catalyst surface. It is believed that the desorption of some surface generated radicals (e.g. OH radicals) may be greatly affected by the thickness of the mass transfer gas film around the mesh wires, which in turn is affected by the gas flow rate passing through the mesh.