Kinetics of the direct DME synthesis from CO2 rich syngas under variation of the CZA-to-γ-Al2O3 ratio of a mixed catalyst bed

The one-step synthesis of dimethyl ether over mechanical mixtures of Cu/ZnO/Al2O3 (CZA) and γ-Al2O3 was studied in a wide range of process conditions. Experiments were performed at an industrially relevant pressure of 50 bar varying the carbon oxide ratio in the feed (CO2 in COx from 20 to 80%), temperature (503–533 K), space-time (240–400 kgcat s mgas−3), and the CZA-to-γ-Al2O3 weight ratio (from 1 to 5). Factors favoring the DME production in the investigated range of conditions are an elevated temperature, a low CO2 content in the feed, and a CZA-to-γ-Al2O3 weight ratio of 2. A lumped kinetic model was parameterized to fit the experimental data, resulting in one of the predictive models with the broadest range of validity in the open literature for the CZA/γ-Al2O3 system.