PSA Nitrogen generation plant based on the PSA process consist of two absorbers filled with carbon molecular sieves, which has the property to absorb Oxygen from compressed air(CMS). Compressed and purified air is passed through the absorbers in this process. Mainly oxygen is absorbed on the carbon molecular sieves as it has preferential properties for adsorption of moisture first and nitrogen enriched gas is leaving the absorber. The oxygen concentration can be reduced to almost all required levels. During adsorption in one adsorbed, the second absorber is totally regenerated just by depressurization to ambient pressure. The oxygen enriched off gas is vented. After about one minute adsorption in one adsorbed, the process controller is switching over to the second absorber to produce nitrogen on a continuous basis.