Separation of methanol-tetrahydrofuran mixtures by heteroazeotropic distillation and pervaporation

The experimental investigation of the separation of tetrahydrofuran-methanol by heteroazeotropic-batch-distillation and methanol-hexane by pervaporation is presented. In particular for this last task, four different specialty commercial membranes were tested (varying feed concentration and temperature). The “pore filling” PolyAn membranes show methanol permeance values higher than 5100 GPU (Typ M2VR ); separation factor of 19; and a selectivity of about 119 (Typ M1VR ). From the results, a coupling phenomenon was observed. An assessment of the temperature effect in the pervaporation process corroborates the hypothesis of the presence of a coupling phenomenon. Finally, a discussion is made on two industrial scale units for the separation of the same mixture: a system of a distillation column integrated with a decanter and stand-alone pervaporation unit. The energetic comparison shows that when using pervaporation a large reduction of the energetic consumption compared to a conventional distillation system (up to 29%) can be obtained.