Permeation of pure carbon dioxide and methane and binary mixtures through cellulose acetate membranes

Abstract

Abstract Steady‐state permeation rates for pure CO 2 and CH 4 and their binary mixtures through homogeneous dense cellulose triacetate membranes have been measured at three temperatures between 20 and 40°C and pressures up to 2.8 MPa. The pressure dependence of the mean permeability coefficient for CO 2 can be described by the total immobilization model in conjunction with a modified free‐volume model. No appreciable pressure dependence of the permeability coefficient for CH 4 is observed, while the permeability coefficients for CH 4 in binary mixture of CO 2 and CH 4 depend on applied gas pressure. The pressure dependences of the mean permeability coefficients for the components in the binary mixture are discussed in terms of the above mobility model. Membrane plasticization induced by CO 2 affects permeation by both gases.