Aspen Adsorption simulation breakthrough curve to determine adsorption time in CH4/N2 adsorption separation by activated carbon

Background: Pressure swing adsorption (PSA) is a crucial technology for CH4/N2 gas separation. While Aspen Adsorption numerical simulation offers an efficient approach to studying this process, precise guidelines for parameter setting are lacking. This study aims to address this gap using activated carbon as an adsorbent. Methods: Aspen Adsorption simulations were used to develop breakthrough curves and virtual tower models for CH4/N2 separation. The study analyzed the impact of adsorption time on product purity and recovery. Additionally, concentration curves were examined to determine their influence on adsorption time setting. Significant Findings: The optimal adsorption time for CH4/N2 adsorption on activated carbon was determined to be 850 s, which corresponds to the initial change in slope of the concentration curve. At this point, the system achieves optimal performance, with a CH4 purity of 82.3 % and a recovery rate of 95.4 %. Furthermore, near the initial slope change (850 s), the concentration curve stabilizes, and the bed utilization rate reaches a higher level. To prevent output gas contamination, the step conversion process should be initiated before the breakthrough point (1450 s). This study provides valuable guidelines for optimizing pressure swing adsorption operations in CH4/N2 separation using activated carbon.