Investigation of activity and selectivity of redox catalysts in oxidative coupling of methane in fluidized bed reactor

Abstract

In this study, oxidative coupling of methane on Redox catalysts in fluidized bed reactor was investigated. For this purpose, the catalyst Mn-Na₂WO₄/SiO₂ was selected as a Redox catalyst. In order to investigate this catalyst, transient state experiments were designed and performed. Then, the different reaction conditions on this catalyst in a fluidized bed reactor were investigated. In transient state experiments, methane feed without the presence of oxygen in the gas phase was sent incrementally on the catalyst and oxidative coupling of methane was examined. Reactor output was analyzed by two systems of GC and GC-MS. The effect of different operational temperatures on the amount of production of coupling products showed that the catalyst has Redox features. With increasing catalyst bed temperature, mobility of oxygen in network increases, which leads to an increase in production. Reoxidation of catalyst bed with oxygen and repeating the experiment and the results confirmed the property of redox catalyst. Then, transient state experiments at temperatures of 800 and 850 ^oC were repeated with the same conditions and the percentage of methane conversion, selectivity, and mole percent of components were investigated. It was observed that at first, methane conversion is high and then as the oxygen of the catalyst and the speed decrease, methane conversion decreases dramatically. According to the chart of mole composition, when the conversion rate is high, the main products of coupling reaction are C₂H₆, C₂H₄ is.

Keywords: Oxidative coupling of methane; fluidized bed reactor; redox catalyst; transient state