ANALYSIS OF MEMBRANE SEPARATION PARAMETERS

This study is concerned with the separation of gas mixtures by selective permeation through nonporous polymeric membranes, a technique that has made considerable progress in recent years. First, several theoretical methods for calculating the separation achievable in a single permeation stage are reviewed and their advantages and limitations are discussed. The methods under consideration assume two idealized flow regimes inside the stage, which are characterized by (a) perfect mixing on both sides of the membrane and (b) cross-flow with no mixing on either side of the membrane. Computer programs for the numerical evaluation of these methods are presented. Second, the effects of several important process variables on the single-stage separation and membrane area requirements are outlined in a parametric study, with special reference to the separation of oxygen from air. The variables include (a) the ratio of pressures on the two sides of the membrane, (b) the pressure level at constant pressure ratio, (c) the fraction of feed permeated (the stage “cut”), and (d) the ideal separation factor. The practical implications of the results are also discussed. © 1969, Taylor & Francis Group, LLC. All rights reserved.