In this study, the condensation of methanol and water in unoccupied layers near the coolant tubes of the gas-cooled reactor in mega- methanol plants are investigated. In the Lurgi mega-methanol plants, named conventional configuration (CC), water-cooled reactors are in series with the gascooled reactor. These reactors are composed of only two sections, shell and tubes. In the novel configuration (NC), the gas-cooled reactor is modified and consists of three sections including shell, tubes, and mesh. A perforated plate, named mesh, is surrounding each tube by 5mm from the outer wall of the tube. In the aforementioned space, which has no catalyst, condensation occurs. The coolant temperature in the inlet of the tube of gas-cooled reactor in NC is 20 K smaller than that of CC. The temperature reduction leads to more gas condensation and as a result,the Methanol production of NC increases by 20% compared with CC. A one-dimensional modeling is applied to compare the performances of NC and CC. The results of CC are validated with industrial data.