The enhancement of hydrogen recovery in PSA unit of domestic petrochemical plant

Abstract

In this work a mathematical model is employed to simulate the industrial layered PSA unit of domestic petrochemical plant which operates for purification of hydrogen. The outlet stream of this plant has about 99.99% purity in hydrogen and the hydrogen recovery is about 75%. A good agreement was observed between the simulation results and the plant data. Moreover, in this study, the effect of cycle time and feed flow rate on hydrogen recovery and product purity is investigated and an optimal value is estimated for cycle time and feed flow rate. The optimal sub cycle time causes to reduce the pollution load of the sorbents. Reduction of pollution load of adsorbents increases the absorber life time and consequently, decreases operating cost of PSA unit of domestic petrochemical plant that allocates for purge of adsorbents. The results show that by applying the optimal cycle time and optimal feed flow rate as the operating conditions, hydrogen recovery of the PSA unit increases from 75% to 80% and 77.5% respectively, and hydrogen purity of the product stream slightly reduces. This phenomenon increases purified hydrogen that is fed to hydrogenation unit.