Special Aspects of DME Production from Synthesis Gas over Mixed Catalysts

Abstract

The process of the production of dimethyl ether (DME) from synthesis gas over a mixture of catalysts for methanol synthesis (25,10 wt.% ZnO; 64,68 wt.% СuO; 10,04 wt.% Al₂О₃) and for methanol dehydration (γ-Аl₂O₃) was studied at different modes of catalyst loading (one-, two-, three-bed). A common for all the modes regularity was established: The total conversion of CO decreases with temperature elevation, the conversion to methanol being decreased but to DME increased. The highest selectivities to DME and DME yields were observed in the case of the three-bed loading. The highest DME yields were obtained at 250–285 °C. It was shown that the use of a mechanical mixture of the catalyst for methanol synthesis and alumina allows effective production of DME from nitrogen-ballasted (20 vol.%) synthesis gas with a low ratio H₂/CO = 1, that is unfavorable for methanol synthesis, while DME yield per feed may reach ca. 10 wt.%.