PSA Nitrogen generators:
Pressure swing adsorption.
In the PSA process, compressed air first passes through a combination of filters to remove entrained oil and water. The purified air is then directed to one of two adsorption vessels that are packed with carbon molecular sieves (CMS). The remaining impurities, such as carbon dioxide and residual moisture, are adsorbed by the CMS at the entrance of the adsorbent bed. At high pressure, the CMS selectively adsorbs oxygen, allowing nitrogen to pass through at the desired purity level. While one vessel is producing nitrogen, the second vessel is depressurized to remove the adsorbed oxygen, which is then vented to the atmosphere. The automatic cycling of adsorption and desorption between the two beds enables the continuous production of nitrogen.
A large range of flow and purity combinations can be met by adjusting the size of the air compressor and adsorption vessels containing the CMS. PSAs can economically produce nitrogen gas at flowrates from less than 5,000 scfh to greater than 60,000 scfh, and at purities ranging from 95% to 99.9995%.