Process for separating liquid mixtures

摘要

The invention is directed to a process for separating liquid mixtures and an apparatus for separating liquid mixtures by pervaporation. The process of the invention comprises:
- passing a stream of the liquid mixture over a permeable non-porous selective membrane, said membrane being selective for at least one of said first and second compounds, whereby at least part of the stream passes through said membrane leaving the other side of said membrane as a vapor, with the remainder forming a retentate stream, and
- condensing said vapor on a condenser surface having a lower temperature than the vaporizing stream to give a distillate stream, said condenser surface forming a non-permeable heat conducting separation wall between said distillate stream and a cooling stream which cooling stream is
a) said feed stream or
b) said retentate stream,
so that heat can be transferred between the vapor and the cooling stream, wherein the distance between said membrane and said condenser surface is smaller than 10 mm, and
wherein the vapor pressure of said distillate stream is lower than the vapor pressure of the compounds in the vaporizing stream for which the permeable non-porous selective membrane is selective, resulting in sufficient driving force for the separation to occur.