ABSTRACT
Pervaporation is a membrane separation process for miscible liquids, such as alcohol and water. Unlike other membrane separation processes, a phase change from liquid to vapour occurs during permeation. As a consequence the energy consumption in pervaporation is higher than that of other membrane processes due to the need to supply the heat of vaporisation of the permeate. In recent years work at the BP Research Centre, Sunbury, has resulted in the development of a new generation of high performance polymeric pervaporation membranes that combine an exceptionally strong selectivity for water with a high permeate flux. The membranes have been developed primarily for the dehydration of alcohols; their high selectivity ensures that the permeate has a low solvent content while their high flux allows a substantial separation from a compact plant. Use of these membranes in applications currently being targeted by Kalsep, a BP Ventures Company, can result in energy savings of approximately 50% over distillation.
