(397d) Effect of an Equalization Step on the Minimum Bed Size Factor of a Rapid Pressure Swing Adsorption Process

Rapid pressure swing adsorption (RPSA) is an advancement of PSA technology for the purpose of process size reduction. This is advantageous for small scale processes such as portable oxygen concentrators where the main objective is a lightweight device. The productivity of RPSA processes is typically represented by the bed size factor (BSF), which is inversely related to productivity. Significant BSF reduction is possible with small diameter particles and fast cycling. However, at some point, it is thought that there is a limit to the possible BSF reduction. It is still relatively unknown what causes a minimum BSF and if it the same for all types of cycles.

The main objective of this study was to determine what effect operating with a pressure equalization step has on the minimum BSF. An equalization step is often employed to reduce the power requirement of a RPSA process. The process in this study used a commercial LiLSX zeolite (~0.5 mm in diameter) to compare results of traditional 4-step feed pressurization cycles with cycles operating with a product end pressure equalization step. The results from the 4-step cycles demonstrate a definite minimum in BSF at a cycle time ~ 4 seconds for a product oxygen purity ~ 96% (argon free air feed). However, the equalization step cycles were able to go to even lower cycle times without a measurable minimum BSF. Possible reasons for why this is occurring will be discussed.