(a) the process employs an adsorption vessel having a feed port for introducing the feed gas and a product port for withdrawing product gas;

(b) located adjacent to feed port is a water removal zone containing a water selective adsorbent for adsorbing the water from the feed gas;

(c) located between the water removal zone and the product port is a CO₂ removal zone containing a CO₂ selective adsorbent for adsorbing the CO₂ from the feed gas;

(d) the process cycles between an adsorption sequence and a regeneration sequence;

(e) during the adsorption sequence:

(i) feed gas is passed through the vessel beginning at the feed port;

(ii) at least a portion of the water selective adsorbent becomes saturated with water;

(iii) at least a portion of the CO₂ selective adsorbent becomes saturated with CO₂; and

(iv) product gas is withdrawn from the product port;

(f) during the regeneration sequence:

(i) the vessel is depressurized to a lower pressure;

(ii) beginning at the product port, a heating regeneration gas is passed through the vessel that provides a quantity of regeneration heat to desorb substantially all of the CO₂ adsorbed during the adsorption sequence and a portion of the water adsorbed during the adsorption sequence; and

(iii) beginning at the product port, a cooling regeneration gas is passed through the vessel to desorb most or substantially all of the remaining water adsorbed during the adsorption sequence;

(iv) the vessel is pressurized with feed gas to prepare the vessel for its next adsorption sequence; and

(g) the water selective adsorbent contained in the water removal zone consists of ten equally thick layers, with layer 1 beginning at the end of the water removal zone adjacent to the feed gas port and proceeding sequentially to layer 10 at the end of the water removal zone which is adjacent the CO₂ removal zone;