What is the working principle of PSA Nitrogen Generator?

PSA nitrogen generator selectively adsorbs oxygen in the air under variable pressure conditions through specific adsorbents (such as carbon molecular sieves), thereby separating nitrogen and oxygen. Under high pressure conditions, oxygen is adsorbed by the adsorbent, while nitrogen flows out through the adsorbent bed to obtain high-purity nitrogen.
1. Detailed steps:
Adsorption stage: When compressed air enters the PSA nitrogen generator, it is pre-treated to remove impurities such as moisture and oil, and then enters the adsorption tower. In the adsorption tower, the carbon molecular sieve selectively adsorbs oxygen and a small amount of other gases (such as carbon dioxide, water vapor, etc.), while nitrogen flows out through the bed to become product nitrogen.
Equal pressure drop stage: When the adsorbent is close to saturation, the system begins to enter the equal pressure drop stage. In this stage, by adjusting the valve, the pressure between two or more adsorption towers is gradually balanced to prepare for the subsequent regeneration stage.
Regeneration stage: In the regeneration stage, the oxygen and other gases adsorbed on the carbon molecular sieve are desorbed by reducing the pressure in the adsorption tower (usually reducing it to below atmospheric pressure). This process can be carried out by reverse flushing, evacuation, etc. to ensure that the adsorbent is fully regenerated and its adsorption capacity is restored.
Pressurization stage: After the regeneration stage, the system enters the pressure boosting stage. In this stage, the bed pressure is restored to the initial pressure of the adsorption stage by filling the adsorption tower with compressed air to prepare for the next adsorption process.