Influence of CaO–ZnO supplementation as a secondary catalytic bed on the oxidative coupling of methane

A reactor with dual catalyst beds was proposed for the direct improvement of methane productivity to C 2 hydrocarbons. In this bed configuration, methane was converted to ethane and ethylene over lithium supported magnesium oxide as a primary catalytic bed. The reaction tests were performed in the presence of CaO–ZnO catalysts as the secondary bed to convert the methane residue into ethane and ethylene. Both Li/MgO and CaO–ZnO catalysts were prepared by the wet impregnation method, tested in the dual fixed bed quartz reactor and characterized by BET, XRD, scanning electron microscopy and temperature programmed desorption of carbon dioxide. Catalytic activity tests were carried out at different temperatures ranging from 675 to 825 °C. The influence of CaO–ZnO supplementation as a secondary bed and its composition on total catalytic performance for oxidative coupling of methane was studied by changing Zn/Ca ratio. The effects of secondary bed dilution with quartz and mixed bed configuration on reaction productivity were also investigated. The experimental results showed that this supplementation could improve total yield toward C 2 production.