PSA technology works on the concept of adsorption to produce a continuous stream of nitrogen gas from compressed air. Nitrogen generator consists of 2 adsorption towers filled with adsorbent material called Carbon Molecular Sieve (CMS). The PSA process cycle consists of two key mechanisms: “Adsorption (Pressurisation) ” and “Desorption (Depressurisation)”.
The pretreated compressed air (CDA) enters the bottom of the on-line tower and follows up through the CMS. Oxygen and other trace gasses are preferentially adsorbed by the CMS, allowing nitrogen to pass through. While one of the tower is in the adsorption phase the other tower is regenerated by de-pressurizing which means the sieve releases the adsorbed gases to the atmosphere and the cycle is then repeated.
Carbon molecular sieve differs from ordinary activated carbons in that it has a much narrower range of pore openings. This allows small molecules such as oxygen to penetrate the pores and be separated from nitrogen molecules which are too large to enter the CMS. The larger molecules of nitrogen by-pass the CMS and emerge as the product gas.