Direct production of dimethyl ether from synthesis gas utilizing bifunctional catalysts

Abstract

In this study, direct synthesis of dimethyl ether from synthesis gas was investigated. For this purpose, H-mordenite zeolite was modified by wet impregnation of aluminum oxide onto it. The prepared catalysts were characterized by AAS, XRD and NH3-TPD analyses. Results of catalytic tests indicated that H-mordenite modified with 8 wt% aluminum oxide was an appropriate catalyst for synthesis of dimethyl ether (DME) from methanol in which methanol conversion and DME selectivity were 99.8 and 96.8%, respectively, without a noticeable change in catalyst stability. A series of bifunctional catalysts, Cu–ZnO–ZrO2/Al-modified H-mordenite, were prepared by co-precipitating sedimentation method and characterized. Synthesis of DME via direct CO hydrogenation was then evaluated in a three-phase slurry reactor. Experimental results showed that Cu–ZnO–ZrO2/Al-modified H-mordenite was a suitable catalyst for the production of dimethyl ether from synthesis gas. Ultimately, the effects of operating conditions such as temperature, pressure and feed flow rate on the process performance of the determined optimum bifunctional catalyst have been reported.