Modeling permeation of CO2/CH4, CO2/N2, and N2/CH4 mixtures across SAPO-34 membrane with the maxwell-stefan equations

The objective of this paper is test the capability of the Maxwell-Stefan (M-S) diffusion formulation to predict binary mixture permeation fluxes across a SAPO-34 membrane using only data on pure-component adsorption isotherms and diffusivities. Experiments were carried out for permeation of CO2/CH4, CO2/N-2, and N-2/CH4 mixtures across a SAPO-34 membrane with upstream pressures ranging to 7.2 MPa, ensuring that high occupancies within the zeolite layer are reached. Good agreement between the M-S mixture model and experiments are obtained provided the binary exchange coefficients D-12 in the M-S equations are assumed to have high enough values to ensure that intercage hops of the species occur independently of one other.