Bulk separation of multicomponent gas mixtures by pressure swing adsorption: Pore/surface diffusion and equilibrium models

A theoretical and experimental study is performed for the bulk separation of a ternary mixture by pressure swing adsorption. Three concentrated products can be obtained by cycling the pressure in the adsorber. Three models are formulated for the cyclic process: equilibrium, Knudsen diffusion, and Knudsen plus surface diffusion. The latter model provides the best results when compared with the experimental data, due to the important contribution of surface flux to the total flux in the sorbent pores.