Kinetics of the direct DME synthesis from CO 2 rich syngas under variation of the CZA-to-γ-Al 2 O 3 ratio of a mixed catalyst bed.

The one-step synthesis of dimethyl ether over mechanical mixtures of Cu/ZnO/Al 2 O 3 (CZA) and γ-Al 2 O 3 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 (CO 2 in CO x from 20 to 80%), temperature (503-533 K), space-time (240-400 kg cat s m gas -3 ), and the CZA-to-γ-Al 2 O 3 weight ratio (from 1 to 5). Factors favoring the DME production in the investigated range of conditions are an elevated temperature, a low CO 2 content in the feed, and a CZA-to-γ-Al 2 O 3 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-Al 2 O 3 system.