Separation of Air Components by Countercurrent and Co-Current Gas Permeation
This Demonstration studies enriching the oxygen content of air with a single-stage membrane module. This problem was first treated in  and later in [2 and 3]. The binary mixture, (oxygen) and (nitrogen), has an ideal separation factor , the ratio of the permeabilities of the two species. The permeability of oxygen is ). The membrane is more permeable to oxygen and has a thickness . The stage cut, , is set by the user. The values of the pressures in the feed and permeate sides are chosen equal to cmHg and cmHg, respectively, which give a ratio of pressures, , equal to 10. The feed rate and composition are given by , , and . This Demonstration computes the reject and permeate compositions as well as the membrane area for the countercurrent and co-current flow cases. .
 W. P. Walawender and S. A. Stern, "Analysis of Membrane Separation Parameters. II. Counter-Current and Cocurrent Flow in a Single Permeation Stage," Separation Science and Technology, 7(5), 1972 pp. 553–584.
 C. J. Geankoplis, Transport Processes and Unit Operation, 3rd ed., Englewood Cliffs, NJ: Prentice–Hall, 1993.
 H. Binous, "Gas Permeation Computations with Mathematica," Chemical Engineering Education, 40(2), 2006 pp. 140–144.