Separation process using pervaporation and dephlegmation

A process for treating a feed vapor comprising an organic compound and water, the process comprising:

• (a) providing a vapor separation membrane having a feed side and a permeate side;
• (b) passing the feed vapor across the feed side;
• (c) withdrawing a residue vapor stream from the feed side;
• (d) withdrawing a permeate vapor stream from the permeate side;
• (e) providing a dephlegmator having a coolant flow side and a gas stream flow side and adapted for partial condensation of a gas stream by providing countercurrent flow between the rising gas stream and a falling condensate stream;
• (f) passing at least a portion of the permeate vapor stream into the dephlegmator as a feed gas stream;
• (g) flowing a coolant across the coolant flow side in heat-exchanging relationship with the feed gas stream;
• (h) withdrawing a product vapor stream as an overhead stream from the dephlegmator;
• (i) withdrawing a product condensate stream as a bottom stream from the dephlegmator.

A fermentation process, comprising:

• (a) performing a fermentation step, comprising:
• (i) introducing a biomass into a fermentation reactor;
• (ii) fermenting the biomass, thereby forming a fermentation broth comprising the biomass and a fermentation product;
• (b) withdrawing a portion of the fermentation broth from the fermentation reactor;
• (c) performing a pervaporation separation step, comprising:
• (i) providing a membrane having a feed side and a permeate side;
• (ii) passing the portion of the fermentation broth as a feed solution across the feed side;
• (iii) withdrawing a residue solution stream from the feed side;
• (iv) withdrawing a permeate vapor stream from the permeate side;
• (d) providing a dephlegmator having a coolant flow side and a gas stream flow side and adapted for partial condensation of a gas stream by providing countercurrent flow between the rising gas stream and a falling condensate stream;
• (e) passing at least a portion of the permeate vapor stream into the dephlegmator as a feed gas stream;
• (f) flowing a coolant across the coolant flow side in heat-exchanging relationship with the feed gas stream;
• (g) withdrawing a product vapor stream as an overhead stream from the dephlegmator;
• (h) withdrawing a product condensate stream as a bottom stream from the dephlegmator.