(615d) Applicability of an Equilibrium Theory Model of a PSA Process Involving Equalization Steps

Pressure equalization between beds (bed-to-bed or BB) and also between beds mediating tanks (bed-to-tank-to-bed or BTB) in pressure swing adsorption (PSA) processes are critical steps for achieving higher enrichment of heavier gas in the heavy product and higher recovery of light gas in the light product. However, only minimal attention has been given to the utilization of an empty tank in the pressure equalization step. This empty tank does not contain any adsorbent and is simply used as a medium for internal gas storage. This kind of equalization step is referred to as a BTB equalization step. Equalization tanks can be useful to decrease the number of the beds and to decrease the number of idle steps in PSA cycle schedules.

A recently developed binary, linear isotherm, isothermal equilibrium theory model of equalization steps has been evaluated against numerical simulations of a mass transfer limited separation process separating CO₂ and N₂ on 13X. In this presentation the ability of the equilibrium theory model to predict the performance of the PSA process and the final pressures of the equalization steps, whether BB or BTB equalizations under isothermal and adiabatic conditions are presented, evaluated and discussed.