Abstract: A process and system for removing contaminants from air comprises flowing a compressed air stream comprising water and carbon dioxide to a first adsorbent zone for contacting with a first adsorbent effective in the adsorption of water by flowing the air in a direction within the first adsorbent zone parallel with the axis of the first adsorbent zone to form a dry gas; flowing the dry gas from the first vessel to a second adsorbent zone comprising a second adsorbent disposed in a radial arrangement about the same axis to remove carbon dioxide. Regeneration of the adsorbent beds may be carried out independently.