The Technology of Pressure Swing Adsorption (PSA)
This is one of technology used to separate Nitrogen from the air. The principle of PSA technology is O2, CO2 and CO molecules are smaller than Nitrogen molecule. Under a certain pressure when air passes through a tank filled with carbon molecular sieve (CMS), the O2, CO2 and CO molecules will be trapped and adsorbed by the CMS. The O2, CO2 and CO molecules diffuse into the pore structure of CMS, and the bigger Nitrogen molecules are allowed to pass through the tank. Hence, the purified Nitrogen is produced.
About CMS (Carbon Molecular Sieve)
Carbon molecular sieve is the most important part of N2 generator, it separates N2 and O2 to obtain high purified N2.
The advantages of PSA are High Nitrogen Purity up to 99.9995% and low operating costs.
The Membrane Technology
The membrane system is based on the principle of differential velocity with which various gas mixture components permeate membrane substance. The driving force in the gas separation process is the difference in partial pressures on different membrane sides.
Air separation using Membrane technology occurs when compressed air is forced into a cylindrical cartridge functioning as a spool with specifically reeled polymer fibres.
These hollow fibres selectively permeate oxygen, water vapour, and other impurities out of its sidewalls, allowing Nitrogen to flow through its centre and emerge as purified Nitrogen.
The advantage of Membrane Technology is cost benefits in terms of scalability and maintenance cost, the disadvantages are limited capacity and relatively low purity (95%).