Modeling Permeation of CO₂/CH₄, CO₂/N₂, and N₂/CH₄ Mixtures Across\nSAPO-34 Membrane with the Maxwell−Stefan Equations

Abstract

The objective of this paper is test the capability of the Maxwell−Stefan (M−S) diffusion formulation to\npredict binary mixture permeation fluxes across a SAPO-34 membrane using only data on pure-component\nadsorption isotherms and diffusivities. Experiments were carried out for permeation of CO₂/CH₄, CO₂/N₂,\nand N₂/CH₄ mixtures across a SAPO-34 membrane with upstream pressures ranging to 7.2 MPa, ensuring\nthat high occupancies within the zeolite layer are reached. Good agreement between the M−S mixture model\nand experiments are obtained provided the binary exchange coefficients Đ₁₂ in the M−S equations are assumed\nto have high enough values to ensure that intercage hops of the species occur independently of one other.