PSA (pressure swing adsorption) is an alternative technology for air separation, able to produce a continuous stream of nitrogen by means of air filtration. High quality compressed air passing  through carbon molecular sieves, placed inside two vessels, separates thanks to carbon porosity. Oxygen is adsorpted into molecular hollow, while nitrogen passes through and is collected as product of the process. Alternative cycles of adsorption and regeneration of carbons give continuity to production. Air pressure and timing of cycle’s control leads up with to requested purity.