Fractionation of air by adsorption

摘要

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. By operation in the described manner there are recovered for any desired use, nitrogen of high purity and an oxygen-enriched gas product.