| abstract |
A method of producing oxygen by using a three-stage pressure swing adsorption unit, where the method is used to separate nitrogen and oxygen from the feed air stream, the product can be oxygen or nitrogen, or both. The method uses three-stage pressure swing adsorption units that are connected in series. In the first stage, carbon dioxide, water and part of the nitrogen are removed and the nitrogen is concentrated. In the second stage, nitrogen is additionally separated from the incoming intermediate gas from the adsorption stage in the adsorption tower of the first stage, and oxygen is concentrated to the desired concentration. In the third stage, nitrogen and argon are further separated from the incoming oxygen-enriched gas mixture from the adsorption stage in the adsorption tower of the second stage, and the oxygen concentration is increased to 95% by volume or more. In the first stage, adsorption towers pass through the stages alternately in a cycle: adsorption (A), purge (P '), evacuation (VC), countercurrent equalizing gas pressure increase of the second stage (2ER), purge gas pressure increase (R'), final pressure increase (FR); in the second stage, the adsorption towers pass through the stages alternately in the cycle: adsorption (A), countercurrent equalizing pressure reduction (BD '), final pressure increase (FR); in the third stage, the adsorption towers pass through the stages alternately in a cycle: adsorption (A), purging the oxygen product (P '), reducing the pressure of the oxygen product (D), increasing the pressure of the purging gas (R'). |