This Demonstration studies enriching the oxygen content of air with a single-stage membrane module. This problem was first treated in [1] 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.
.