Aspen adsorption simulation for the effects of purge flow rate and vacuum pressure in vacuum pressure swing adsorption

Abstract

Vacuum pressure swing adsorption (VPSA) process has received great attention for gas separation because it is a clean process with relatively low energy consumption and produces no waste. In order to optimize the VPSA process, a number of experiments must be performed to obtain an optimal set of operating parameters. To reduce a number of experiments, process simulation has been widely used to study the effects of the operating parameters. In this study, a mathematical model was constructed, and the simulation was performed using Aspen Adsorption. The model was first validated for the separation of carbon dioxide (CO2) from gas mixtures using zeolite 13X and zeolite 5A as the adsorbent material. Then, the model was employed to study the effects of purge flow rates and levels of vacuum pressure on the efficiency of the adsorbent regeneration. For both zeolite 13X and 5A, the purge flow rate of 20 SLPM resulted in a greater desorption of CO2 than the purge flow rate of 10 SLPM and 5 SLPM. Similarly, the vacuum pressure of 5 kPa resulted in a greater desorption of CO2 than the vacuum pressure of 10 kPa and 50 kPa. The results also showed that the regeneration of zeolite 5A was more difficult than zeolite 13X, despite the fact that the CO2 adsorption capacity of zeolite 5A was lower than that of zeolite 13X.