Purification of gases using solid adsorbents

A method for the removal from a feed gas stream of at least two contaminating gas components comprising carrying out repeated cycles of operation which comprise:

• feeding the feed gas stream in a feed direction at a first pressure and at a first temperature in contact with a solid adsorbent capable of adsorbing a first of said contaminating gas components more strongly and a second of said contaminating gas components less strongly so that said first contaminating gas component is adsorbed in an upstream portion of said adsorbent and said second contaminating gas component is adsorbed principally in a more downstream portion of said adsorbent,
• halting the feeding of said feed gas stream,
• depressurising the gas in contact with the adsorbent to a second, lower pressure, feeding a regenerating gas at said second pressure and at a second temperature higher than said first temperature in a direction counter-current to said feed direction in contact with said adsorbent to produce a heat pulse travelling in said counter-current direction to desorb said less strongly adsorbed second contaminating gas component from the downstream (with respect to the feed direction) portion of the adsorbent by TSA whilst at the same time desorbing the more strongly adsorbed first contaminating gas component from the upstream (with respect to the feed direction) portion of the adsorbent by PSA,
• ceasing regenerating gas before the heat pulse travels as far as the upstream portion of the adsorbent in which is adsorbed the first contaminating gas component,
• and repressurising said adsorbent.