Influence of Tandem Catalysis and Optimised Parameters on Syngas-Dimethyl Ether Co-fed Process for Ethanol Direct Synthesis in a Dual Bed Reactor

Abstract

Ethanol use mainly as an alternative green fuel has attracted global attention, hence need for the development of more improved synthesis pathways. In this work, we proposed an in situ direct ethanol synthesis pathway, where dimethyl ether (DME) was co-fed with syngas (CO + H2) over a combination of metal impregnated zeolite (Cu-MOR) and ternary oxide CuO/ZnO/Al2O3 (CZA) catalysts, disjointly packed in a dual bed reactor. The route first transformed DME into an intermediate ester (methyl acetate) by carbonylation reaction on the upper modified zeolite catalyst, followed by hydrogenation of the intermediate ester into ethanol on the lower CZA catalyst. Dimethyl ether conversion reached 75.72% with an ethanol selectivity of 48.05% under Cu loading amount of 13 wt% of zeolite support.