Abstract: Hydrogen-containing gas mixtures are subjected to selective adsorption in a pressure swing cyclic system to remove carbon dioxide and/or hydrocarbon gases, obtaining high recovery of hydrogen at high purity. The system can also be employed for separation of methane from admixture with CO.sub.2.

Abstract: A method for removing low concentrations of oxidizable organic contaminants from an oxygen containing inert gas comprises: (1) adsorbing the contaminants on a sorptive media which contains an oxidation catalyst in a reaction zone; (2) interrupting the flow of the gas through said sorptive media; (3) thermally desorbing the adsorbed contaminants; (4) oxidizing the desorbed contaminants to innocuous reaction products; and (5) venting and purging the reaction products from the reaction zone.

Abstract: Ambient air, during an on-stream period, is passed serially through a pretreatment adsorbent bed removing moisture and carbon dioxide therefrom and the thus dried and purified air then passed through a main adsorbent bed selective for retention of nitrogen, the oxygen-rich effluent being collected in an expandable receiving vessel. Nitrogen of high purity, is desorbed by suction from the main bed in a direction chamber to that of the initial air charge and passes from the main bed into and through the pretreatment bed to a collection vessel. Preceding the vacuum desorption step both the pretreatment bed and the main bed are rinsed with the high purity nitrogen product gas from a previous stage in the operation. Following evacuation the beds are repressured with a portion of the oxygen-rich gas drawn from the expandable receiving vessel. At least two parallel trains of adsorbent beds are employed in alternating timed sequence for continuity of operation.

Abstract: Ambient air, during an on-stream period, is passed through a first adsorbent bed removing moisture and carbon dioxide and then through a second bed of adsorbent selective for retention of nitrogen, the oxygen-rich effluent being collected in an expandable receiver. Desorption of both beds is effected by reducing the pressure at the inlet end of the first bed causing desorbed nitrogen from the second bed to pass through the first bed, desorbing moisture and CO.sub.2 therefrom. Further removal of moisture and CO.sub.2 from the first bed is then effected by lowering the pressure of that bed further, while the second bed is restored to its on-stream pressure by admission of enriched oxygen thereto from the expandable receiver.