Role of different pressure equalization strategies on cycle performance of dual-reflux pressure swing adsorption for biogas upgradation

Abstract. Cycle sequence plays a crucial role in determining the performance of dual-reflux pressure swing adsorption (DR-PSA) process. Pressure equalization (PE) is one of the cycle modifications that is often implemented in DR-PSA, which can influence the performance of the process. In this study, numerical simulations of a 2-bed DR-PSA, with different PE strategies, were conducted in Aspen Adsorption in order to elucidate the role played by the PE step on the cycle performance. The process was designed for biogas upgradation from a binary gas mixture of a 45 mol% CO2 + 55 mol% CH4, with silica gel as solid adsorbent. The introduction of the PE step into the cycle sequence enhances the cycle performance in terms of product purity, recovery, and cycle work. The extent to which the cycle performance improves depends on the PE strategies being implemented.