Effect of CO_2 content in the feed on coke formation in the direct synthesis of DME over a CuO-ZnO-ZrO_2/SAPO-18 catalyst

摘要

The increasing need for clean fuel alternatives has aroused the interest of dimethyl ether (DME) in the recent years. Besides its well known properties as green coolant and propellant, DME can replace methanol as raw material for the production of high added value products (C1 chemistry, olefins), can be used as hydrogen source or as an alternative to automotive diesel or domestic LPG. In addition, due to the advantages over the synthesis of methanol, DME synthesis process is considered to be a key route for the large-scale CO_2 valorization. In this regard, a great effort of the recent researches is focused on tailoring the bifunctional catalysts used in this process, composed of a metallic function (for methanol synthesis) and an acid function (for methanol dehydration to DME). On the one hand, by adding new promoters for stabilizing the active Cu sites, and on the other hand, studying more hydrothermally stable acid functions. Among the catalysts studied in the literature, CuO-ZnO metallic functions with ZrO_2 as promoter are outstanding for CO_2 hydrogenation [1].