How a PSA Nitrogen generator works

The Atlas Copco NGP+ nitrogen gas generator provides all the advantages of PSA technology in a compact, reliable and efficient plug-and-play solution

December 10, 2020

How a PSA Nitrogen generator works

Estimated reading time: 5 minutes

The air we breathe is about 78% nitrogen, but nitrogen at a higher level of purity has a wide variety of practical applications across many industries. Nitrogen is generated by separating nitrogen molecules from other molecules within a clean, dry compressed air stream, resulting in a purified supply of nitrogen.

For some applications, such as tire inflation and fire prevention, relatively low purity levels (between 90% and 97%) are required. Other applications, such as food/beverage processing and plastic molding, require higher levels of purity (from 97% to 99.999%).

Watch this video to learn more about Nitrogen

Pressure Swing Adsorption (PSA)

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.

PSA generating Nitrogen in-house

Companies that generate their own nitrogen in-house enhance production flexibility by ensuring they have the nitrogen they need, at the level of purity they need, when they need it.

Generate nitrogen in-house and there is no worry about running out because there is no third party supplier. This eliminates constant order processing, refills and delivery costs. It also frees up space otherwise needed to store nitrogen bottles (both full and empty).

Ask an air system professional about the best solution for generating nitrogen in-house.

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How a PSA Nitrogen generator works

The Atlas Copco NGP+ nitrogen gas generator provides all the advantages of PSA technology in a compact, reliable and efficient plug-and-play solution