Patent ID: 7785471
Filing Date: 2010-08-31
Classification: B01D,C07C,C10G

Abstract:
1. A process for separating aromatics from a hydrocarbon feedstream containing aromatics and non-aromatics comprising: a) contacting one side of a membrane assembly with a hydrocarbon steam, wherein the membrane assembly is comprised at least two polymeric membrane elements and at least two polymer films, wherein a retentate stream and a permeate stream are extracted from the membrane assembly, and wherein at least one polymeric membrane element is comprised of a dianhydride, a diamine, a cross-linking agent and a difunctional dihydroxy polymer selected from: b) extracting a permeate stream from the opposite side of the membrane assembly, wherein the weighted average of the carbon weights of the aromatics in the permeate stream is at least one carbon weight higher than the weighted average of the carbon weights of the aromatics in the feedstream, wherein the membrane assembly is composed of a top layer of polymer film, a bottom layer of polymer film, and from 2 to 6 polymeric membrane elements disposed therebetween, and wherein each polymeric membrane element is comprised of a middle layer of a porous polytetrafluoroethylene film having a pore size from about 0.1 to about 0.3 microns surrounded on to and bottom with cast polymer layers comprised of the reaction product of the dianhydride, diamine, cross-linking agent, and difunctional dihydroxy polymer.