The effect of number of pressure equalization steps on the performance of pressure swing adsorption process

• In this study, the different cycle sequences were designed and compared for one pressure swing adsorption (PSA) process.
• The effect of cycle schedule on the performance of a six-bed PSA process was considered.
• The effect of adsorption pressure, purge to feed (P/F) ratio, and feed velocity on product purity and recovery has been investigated.
• A target function has been developed for comparison of performance for the different cycles.

Cycle sequence has an important effect on the performance of pressure swing adsorption (PSA) processes. Pressure equalization steps influence significantly the purity and recovery of product, and therefore, may be properly designed to improve the performance of PSA processes. Open literature lacks of a systematic study on the effect of cycle sequence design on the performance of a specific PSA process as a controlling parameter. In this work, the results of recent studies on different cycle schedule design strategies have been used as a basis for comparing various cycle schedules (proposed by the authors of this work) on the performance of a six-bed PSA process for hydrogen purification. Three different cycle sequences have been designed, the pressure equalization and idle steps consisting the main controlling parameters. Simulation results showed that designs with more pressure equalization steps result in higher product recovery and those with less pressure equalization steps result in higher product purity. The proper performance of a PSA process is a tradeoff between product recovery and product purity. In this view, a target function has been developed that enables us to lump the latter performance parameters into one function for comparing the performance of the different cycles employed.