Effect of adsorbent heterogeneity on performance of a PSA process for bulk gas separation: a parametric simulation

The effect of adsorbent heterogeneity on the performance of an adiabatic pressure swing adsorption (PSA) process for separation of bulk C2H4 from an inert gas (helium) using the BPL carbon as the adsorbent was numerically estimated employing a detailed mathematical model for the process. The heterogeneous Toth model was used to describe the equilibrium adsorption isotherms for C2H4 and a linear driving force model was used to describe the adsorbate mass transfer rate in the simulation. The variations in the isosteric heat of adsorption of C2H4 with adsorbate loading was included in the simulation. The study indicates that adsorbent heterogeneity negatively affects the key process performance variables by increasing the bed size factor and reducing the helium recovery. Actual performance data for a PSA process using a bench or pilot scale unit is required to reliably estimate the complexity introduced by adsorbent heterogeneity.