Optimal startup operation of a pressure swing adsorption

Pressure swing adsorption (PSA) is a gas separation and purification technology for high purity and small throughput. There exists literature on simulation and optimization of PSA operation; however most of it is based on cyclic steady state (CSS) conditions. There is scant literature on simulations of startup operation. We present the problem formulations of optimal startup in PSA for separating H<inf>2</inf>-CO<inf>2</inf> in this work. Two formulations were considered for the startup, one with the consideration of only the CSS conditions in the objective function and the other one by considering both, the transient and CSS conditions in the objective function. The performance of both the operations was measured in terms of the number of cycles to attain the CSS (N<inf>css</inf>). The consideration of transient conditions demand optimizing the transient profile (until the CSS is achieved) of the manipulated variable, which requires large computational expense, however providing greater benefits in terms of reduced N<inf>css</inf>.