Pressure swing adsorption is a process used for a variety of industrial gas separations and purifications including air separation and hydrogen purification. Rapid pressure swing adsorption (rPSA) is an advancement of this 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. While the process at an industrial scale is well known, rPSA is a relatively new technology at a minuscule scale; much less is known about its operation. RPSA is operated at speeds 1-to-2 orders of magnitude faster than larger scale processes. Small adsorbent particles for mass transfer and high gas velocities to sustain large flowrates allow for high speed operation.
The main objective of this study was to compare rPSA cycle performance under different cyclic operations. Cycle types include vacuum swing adsorption (VSA), VPSA and PSA. Cycles operating with an equalization step are also compared to Skarstrom cycles. A commercial Li-X zeolite (~0.5 mm diameter) was used as the adsorbent in a 2-column air separation process. The system is capable of cycles under 3 seconds with an oxygen product purity of 96% (argon free air).