Patent ID: 7276163

Claim:
A crossflow membrane device for receiving a feedstock and for separating the feedstock into permeate and retentate, comprising: a) a membrane element that receives the feedstock at a feed end face, and separates the feedstock into permeate and retentate, the membrane element comprising: i) a membrane support containing at least one monolith of porous material defining a plurality of passageways with passageway wall surfaces, the passageways extending longitudinally from the feed end face of the monolith to a retentate end face of the monolith; ii) a permselective membrane coating applied to the passageway wall surfaces of at least the channels through which the feedstock flows; and iii) at least one permeate conduit formed within the monolith, the conduit containing a plurality of longitudinal permeate chambers extending substantially the entire length of the monolith, transected proximate the feed end face by at least one permeate channel and proximate the retentate end face by at least one other permeate channel; b) a housing assembly that contains the membrane element, the assembly comprising: i) a housing that contains the element and is spaced from the element to define an annular space between the element and the housing; ii) a feedstock inlet port in communication with the feed end face of the monolith, and a retentate outlet port in communication with the retentate end face of the monolith; iii) a permeate circulation inlet port in fluid communication with the permeate channel or channels through the annular space proximate the feed end face, to allow for the introduction of circulated permeate into the permeate chambers and flow of substantially all of the circulated permeate along the length of the permeate chambers; iv) a permeate outlet port in fluid communication with the permeate channel or channels through the annular space proximate the retentate end face, to allow for the withdrawal of the permeate from the permeate chambers; v) a means of separating the permeate flow from the feed and retentate flows; and vi) where at least one of the permeate channels communicates with the annular space between the membrane device and the housing, in which the annular space is filled with a flow resistance material to reduce permeate flow through the annular space from the feed end of the device to the retentate end of the device.