Improvement in pressure swing in adsorption process for gas separation

Claim 1

A process for selectively separating a desired gas component from a gas mixture of two or more gas com­ponents, which comprises the steps of: (1) introducing the gas mixture under pressure into a cylinder having therein an adsorption column of an adsorbent which selectively adsorbs thereon at least one gas component other than the desired gas component from an inlet of the cylinder, to allow the adsorbent near the inlet to selectively adsorb the gas component other than the desired gas component and to form a zone of adsorbed gas in the column; (2) keeping the introduction of the gas mixture into the cylinder under such condition that the gas mix­ture flows through the column to move the front of the adsorbed gas zone forwards; (3) collecting the desired gas component having passed through the column from an outlet of the cylinder; (4) terminating the introduction of the gas mixture into the cylinder; (5) terminating the collection of the desired gas component; (6) discharging a portion of the pressurized gas mixture remaining in the cylinder; and (7) returning a portion of the collected gas compo­nent back into the cylinder at an intermittently varying rate to flow through the column in the direction opposite to the direction of the movement of the gas mixture in the step (2), to desorb the gas component having been adsorbed on the absorbent of the adsorption column and purge away the desorbed gas component from the cylinder.