SEPARATION OF HYDROGEN MIXTURES BY A 2-BED PRESSURE SWING ADSORPTION PROCESS USING ZEOLITE-5A

A study on a two-bed six-step pressure swing adsorption (PSA) process using zeolite 5A was performed experimentally and theoretically for bu lk separation of H-2/CO and H-2/CH4 systems (70/30 vol %) as major com ponents in coke oven gas. When the pressure is cycled between 1 and II atm at ambient temperatures, 70% H-2 in the feed could be concentrate d to 99.99% in the product with a recovery of 75.87% in the H-2/CO mix ture and 80.38% in the H-2/CH4 mixture. The effects of adsorption pres sure, P/F ratio, adsorption/purge step time, and pressure equalization step time were investigated experimentally. If the product end of an adsorption bed was not contaminated during the adsorption and depressu rizing pressure equalization steps, elongation of both the adsorption and purge steps gave good adsorbent productivity and recovery without any decrease in purity. Certain elongations of step time in the pressu re equalization step resulted in a better performance of a PSA process . When the H-2 mole fraction of effluent stream during the pressure eq ualization step was not high, the initial H-2 purity of the adsorption step was not good because of the contamination of the product end sec tion. These results were analyzed by a mathematical model incorporatin g heat and momentum balances.