Superstructure Model for the Simultaneous Design and Optimization of a Pressure Vacuum Swing Adsorption Process Cycle

The performance of any adsorptive separation process depends on two factors: the adsorbent media and the Pressure/Vacuum Swing Adsorption (PVSA) process cycle. The pool of adsorbents for any separation has grown exponentially over the past decade with the advent of metal–organic chemistry.[Colón, Y. J.; Snurr, R. Q. Chem. Soc. Rev. 2014, 43, 5735–5749]. There are potentially multiple PVSA process cycle pathways that can be chosen for the gas separation.[Sircar, S. Ind. Eng. Chem. Res. 2006, 45, 5435–5448]. To achieve the full potential of a given adsorbent, the operating conditions of the process cycle need to be optimized; this is computationally challenging. Traditionally, the performance of a small set of user-defined PVSA process cycles is chosen for optimization. In this work, we present a superstructure model to simultaneously design and optimize the PVSA process cycle. To highlight the potential of such an approach, we present different case studies related to separating CO₂ from a mixture of CO₂ and N₂ as it is a well-studied and currently relevant separation system. The superstructure model presented in the work covers over two dozen possible PVSA cycle configurations. The framework is also shown to be scalable for adsorbent evaluation by using novel optimization strategies to effectively search the large input search region.