Temperature swing adsorption process for the separation of target species from a gas mixture

A temperature swing adsorption process for separating a target species from a feed gas mixture containing said target species, which process comprises:

• a) subjecting said feed gas mixture containing said target species to an adsorption step by introducing the feed gas mixture into the feed input end of an adsorbent bed that is comprised of an adsorbent material that is selective for adsorbing said target species, which adsorbent bed having a feed input end and a product output end, and which adsorbent bed is operated at a first pressure and at a first temperature wherein at least a portion of the said target species in the feed gas mixture is adsorbed by the adsorbent bed and wherein a gaseous product stream containing a lower mol % of said target species than said feed gas mixture exits the product output end of said adsorbent bed;
• b) stopping the introduction of said feed gas mixture to said adsorbent bed before breakthrough of said target species from the product output end of said adsorbent bed;
• c) reducing the pressure in said adsorption bed to a second pressure in a manner to induce a flow in the adsorption bed that is counter-current to the flow of the feed gas mixture in step a);
• d) externally heating said adsorbent bed to a second temperature higher than said first temperature while simultaneously passing a flow of purge gas, substantially free of target species, counter-current to the direction of the flow of the feed gas mixture in step a), thereby desorbing and recovering at least a portion of the desorbed target species and resulting in the product outlet end of said adsorbent bed being reduced in the amount of the target species;
• e) cooling at least a portion of said adsorbent bed to a third temperature which is lower than said second temperature used in step d);
• and
• f) increasing the pressure in said adsorbent bed to a third pressure.