Oxidative coupling of methane to light olefins using waste eggshell as catalyst

Abstract Catalysts obtained from waste eggshell were prepared by simple thermal treatments using different calcination atmospheres and evaluated in the oxidative coupling of methane to obtain C2-C3 hydrocarbons (OCM process). It was found that the calcination atmospheres influence the specific surface area, the crystallinity, and the surface basicity of the obtained materials. All the samples led to the conversion of methane into light olefins which was favored by the increase in temperature. The best result was obtained at 800 °C for the sample calcined under air flow with a methane conversion of 30% and selectivities of ethylene and propylene of 53% and 3%, respectively. The lowest conversion and selectivity results were obtained for the sample calcined in static air. These results are ascribed to the higher amount and strength of basic sites for the sample calcined under air flow. All catalysts showed high stability at 800 °C during 5 h.