Patent ID: 8425734
Filing Date: 2013-04-23
Classification: B01D

Abstract:
1. A process for separating a feed mixture comprising (i) from about 1% to about 50% by weight of an organic substance whose normal boiling point is between 65° F. (18° C.) and the normal boiling point of water and that does not form a maximum boiling azeotrope with water, or whose normal boiling point is above the normal boiling point of water and that forms a minimum boiling azeotrope with water, (ii) dissolved solids, and (iii) water, said process comprising: (a) distilling said feed mixture in a single distillation column to separate said feed mixture into a first intermediate stream rich in said organic substance relative to said feed mixture and a second intermediate stream that is depleted of said organic substance and rich in said dissolved solids relative to said feed mixture, under conditions whereby said first intermediate stream contains from about 50% to about 99.5% by weight of said organic substance, but below the azeotropic concentration in case of azeotropic mixture; (b) passing at least a substantial fraction of said first intermediate stream through a first membrane that is selectively permeable to water and has a ratio of water permeation flux to flux of said organic substance of about 25 or greater, to separate said fraction of said first intermediate stream into (c) passing at least a substantial fraction of said second intermediate stream through a second membrane having a dissolved solids rejection coefficient for selected solids of from about 65% to about 99.99%, to separate said fraction into