Energy saving strategies for plate reactors in mega methanol plants: a CFD study

Abstract One of the disadvantages of methanol synthesis water-cooled quasi-isothermal reactors is the high energy consumption to produce saturated steam. This study proposes two novel configurations for plate exchanger methanol synthesis reactors with axial-radial flow to minimize energy consumption and maximize methanol production. These configurations are compared via three-dimensional computational fluid dynamics. There are two sets of plates in the plate reactors to cool the gas in the reactor’s shell, which are named inner and outer plates. In novel configuration 1 (NC1), the outer plates are omitted, the first radial part has been considered an adiabatic bed, and the second quasi-isothermal. In novel configuration 2 (NC2), the fresh feed stream has been passed through outer plates for preheating rather than using saturated steam. The benefit of these configurations are reduction of water consumption by 50 % and also energy saving for steam generation. Moreover, methanol production is raised by 3 % in NC1 rather than in conventional configuration. Also, preheating of inlet feed in NC2 leads to an increase of 2 % in methanol. The superior configuration is NC2, although, in NC1, methanol production is higher; also, some hot spot points would have emerged in the middle of the reactor.