Low-pressure DME synthesis with Cu-based hybrid catalysts using temperature-gradient reactor

Dimethyl ether (DME), the target product of this study, has many advantages as diesel fuel. The aim of this study is to develop a catalytic process in which 90% CO conversion to DME and CO₂ from syngas (3CO+3H₂→DME+CO₂) is attained at 1–3 MPa. In such a process, both recycling loop and compression of syngas can be omitted resulting in an economic process based on unused, dispersed and small-scale carbon resources. To overcome the equilibrium conversion limit we designed temperature-gradient reactor (TGR). In TGR, the temperature of the catalyst bed decreases along with the down flow of reaction gas. The performance of the catalyst in TGR was much higher than that in a conventional isothermal fixed bed reactor. For example, 90% CO conversion and high STY (1.1 kg MeOH eqiv./kg cat./h) was attained at the same time in TGR at 550–510 K, 3 MPa.