Novel internally staged permeator designs using a hollow fiber fabric

Five novel internally staged permeator (ISP) designs for membrane-based gas separations are described. Two permeate streams, a low-pressure and an int ermediate-pressure permeate, and a high-pressure retenate stream are produc ed in an ISP. Three of the new designs utilize a woven fabric or alternatin g sheets of fibers to enable contacting patterns that are not possible with previous designs. All designs are compared for the production of an enrich ed oxygen permeate from air. Design and operational parameters were selecte d to maximize the recovery of the enriched oxygen product. Of the new desig ns,the best performer is the co-cross design. The best overall performer is the co-counter design. The co-cross design is able to recover 33% of the f eed as a 42% oxygen permeate while the co-counter design is able to recover 35% of the feed in contrast to the 12% recovery provided by a single count ercurrent stage. However, this increase in recovery comes at the expense of a significant increase in required membrane area: the co-cross design requ ires 20x more area than the countercurrent stage while the co-counter desig n requires 23x more area. All ISP designs are capable of producing higher p ermeate purities than achievable in a single countercurrent stage. The co-c ounter design can recover 12% of the feed as a 52% oxygen permeate while a single countercurrent stage is limited to purities less than 45%.