Effect of adsorption and desorption pressure on the velocity and cycling performance of rapid pressure swing adsorption

Rapid(vacuum) pressure swing adsorption(RPSA or RVPSA) is featured by short cycle time and quick pressure change,which may lead to great variations of flow and mass and heat transfer in the adsorber. The effects of adsorption and desorption pressure on the velocity and cycling performance in an oxygen-production RPSA bed were investigated in this paper. The results show that during the feed pressurization(PR) step in the RPSA process,the up-flow velocity is far larger than the limit value,and slightly larger than it for the rapid vacuum pressure swing adsorption(RVPSA) process. During the blow-down step in both RPSA and RVPSA,the down-flow velocity is greater than the limit value. In comparison to RPSA,RVPSA exhibits a similar gas temperature change around 10℃ but a larger gas temperature gradient. The bed size factor can be effectively reduced with increased oxygen recovery by increasing the adsorption pressure for RPSA,while by lowering the desorption pressure for RVPSA.