Reactivation system for water-carbon dioxide adsorbers

A cyclic process for the separation of water and carbon dioxide contaminants from a feed gas stream by adsorption on a molecular sieve adsorbent to produce a purified gas stream and subsequent regeneration of the adsorbent which comprises:

• (a) passing the feed gas stream at a pressure of from about 90 to 3000 psig and a temperature of from about 40.degree. F. to 130.degree. F. through first and second molecular sieve adsorbent zones, wherein substantially all of the water is adsorbed in the first adsorbent zone and the carbon dioxide is adsorbed in the second adsorbent zone;
• (b) discontinuing the flow of the feed gas stream to the first and second adsorbent zones;
• (c) depressurizing the adsorbent zones through the inlet to a regeneration pressure of between about 14.7 and 100 psig;
• (d) regenerating the first adsorbent zone by introducing heated regeneration gas at a temperature between about 450.degree. F. and 700.degree. F. intermediate the first and second adsorbent zones, and passing the heated regeneration gas through the first adsorbent zone in a direction countercurrent to the flow of the feed gas stream;
• and
• (e) cooling the first adsorbent zone and requenching and cooling the second adsorbent zone by passing cool regeneration gas at a temperature between about 40.degree. F. and 130.degree. F. sequentially through the first and second adsorbent zones in a direction cocurrent to the flow of the feed gas stream.