PROCESS AND APPARATUS FOR CYCLE TYPE PRESSURE SWING ADSORPTION FOR RECOVERING OXYGEN

摘要

PROBLEM TO BE SOLVED: To provide a process and an apparatus for pressure swing adsorption for recovering high purity oxygen from a feed gas containing oxygen, nitrogen and argon. SOLUTION: The process includes stages that (a) the feed gas is passed into a 1st adsorption zone containing an adsorbent selective for the adsorption of nitrogen over that for oxygen and argon and a nitrogen-depleted intermediate gas is withdrawn, (b) the intermediate gas passed into a 2nd adsorption zone containing an adsorbent which is selective for the adsorption of nitrogen over that of argon and selective the adsorption of argon over that of oxygen, (c) an oxygen-enriched product gas is withdrawn from the 2nd adsorption zone, and (d) the feeding of the feed gas is terminated and an oxygen-enriched depressurization gas is withdrawn from the 2nd adsorption zone in the same flow direction as that of (c). The breakthrough of nitrogen can occur from the 1st adsorption zone, and after that nitrogen can be adsorbed in the 2nd adsorption zone.