12 February, 2020
One technology for generating nitrogen is Pressure Swing Adsorption (PSA). Adsorption is the process in which atoms, ions or molecules from a substance (compressed air in this case) adhere to a surface of an adsorbent. A PSA nitrogen generator isolates nitrogen, and the other gases in the compressed air stream (oxygen, CO2 and water vapor) are adsorbed, leaving behind essentially pure nitrogen.
PSA nitrogen generator technology is a simple, reliable and cost-effective approach to nitrogen generation that enables continuous, high-capacity nitrogen flow at the desired level of purity. PSA traps oxygen from the compressed air stream when molecules bind themselves to a carbon molecular sieve. This happens in two separate pressure vessels (tower A and tower B), each filled with a carbon molecular sieve, that switch between a separation process and a regeneration process.
Clean and dry compressed air enters tower A. Since oxygen molecules are smaller than nitrogen molecules, they pass through the pores of the sieve. Nitrogen molecules cannot fit through the pores, so they bypass the sieve resulting in nitrogen of desired purity. This phase is called the adsorption or separation phase. Most of the nitrogen produced in tower A exits the system, ready for direct use or storage.
Next, a small portion of the generated nitrogen is flowed into tower B in the opposite direction. This flow pushes out the oxygen that was captured in the previous adsorption phase of tower B. By releasing the pressure in tower B, the carbon molecular sieves lose their ability to hold the oxygen molecules, which detach from the sieves and get carried away by the small nitrogen flow coming from tower A. This ‘cleaning’ process makes room for new oxygen molecules to attach to the sieves in a next adsorption phase.
The two tower PSA system switches between separation and regeneration to provide continuous nitrogen production at a desired purity level. The Atlas Copco NGP+ nitrogen gas generator provides all the advantages of PSA technology in a compact, reliable and efficient plug-and-play solution.
Ask an air system professional about the best solution for generating nitrogen in-house.