Device and method for removing water and carbon dioxide from a gas mixture using pressure swing adsorption

A method for reducing the concentration of water and carbon dioxide in a gaseous stream using pressure swing adsorption, the method comprising:

• a) passing the gaseous stream through a first adsorbent column to produce a dry flow having reduced water and carbon dioxide content;
• b) dividing the dry flow into a product flow and a purge flow;
• c) increasing the volume and decreasing the pressure of the purge flow to produce an expanded purge flow;
• d) passing the expanded purge flow through a second adsorbent column to produce a moist exhaust flow having increased water and carbon dioxide content;
• and
• e) reversing the direction of flow through the first and second adsorbent columns;
• wherein each of the first and second adsorbent columns comprises a mixture of primary and secondary adsorbents, wherein the primary adsorbent adsorbs water and the secondary adsorbent adsorbs carbon dioxide, wherein the secondary adsorbent comprises a solid amine;
• wherein the mixture is packed in the columns in three layers:
• a top layer, a bottom layer, and a middle layer sandwiched between the top layer and bottom layer,
• wherein both the top layer and the bottom layer contain just primary adsorbent material, and wherein the middle layer contains a mixture of the primary and secondary adsorbent materials.