Pressure swing adsorption process

In a pressure swing adsorption process for the selective adsorption of at least one gaseous component from a feed gas mixture comprising conducting the mixture in cyclic alternation through at least three adsorbers, each of said at least three adsorbers passing through a switching cycle in staggered fashion with respect to one another, said switching cycle including (a) an adsorption phase wherein said feed gas mixture is introduced at an elevated inlet pressure into an adsorber, said at least one gaseous component is adsorbed, and unadsorbed product gas is withdrawn from the adsorber;

• (b) a cocurrent expansion phase, after termination of said adsorption phase, during which the adsorber is regenerated by being depressurized to form an expansion gas which is passed on at least in part to other adsorbers for partial repressurization thereof;
• and (c) a pressurization phase during which the adsorber is subsequently repressurized to said inlet pressure, the improvement comprising each of said adsorbers being divided into a first adsorber section and a second adsorber section, said first and second adsorber sections being connected in series, and during said adsorption phase said feed gas mixture being respectively conducted through said first and second adsorber sections, said adsorber sections being isolated from each other after said cocurrent expansion phase and said first adsorber section being subjected to further depressurization while said second adsorber section is maintained at a higher pressure.