Study of the conditions of liquid-phase separation of the methanol-oil-water fraction in the column for main distillation of methanol

This report studied the conditions of liquid-phase separation of the methanol-oil-water (M.O.W.) fraction in a column for distillation of methanol. Results indicated that the ratio of isobutanol to propanol in crude methanol obtained 50 under atm pressure is approximately 40:60. The heterogeneity region of the system of key components of the m.o.w. fraction contracts to a quarter of its original width, with a methanol content below 2.5 mass % in the heterogeneous mixture. Considerable dilution would be needed to lower the methanol content in the M.O.W. fraction to this level; this would lead to extraction of propanol into the aqueous layer, its return into the column, and a consequent decrease of the isobutanol-propanol ratio. Therefore, installation of a separator in main distillation column operating with crude methanol obtained under 50-100 atm pressure is inadvisable even for production of distilled methanol containing ethanol as an impurity.