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Atlas Copco Nitrogen Generator
Nitrogen Nitrogen Generators

How does a Nitrogen Generator work? PSA vs. Membrane Separation


As the use of Nitrogen gas is becoming more and more standard in everyday applications, from food and beverage manufacturers, food packaging, laser cutting, wastewater treatment and more, we will take a more in-depth look at how a nitrogen generator works and the differences between PSA and membrane separation technology.

When paired with a compressed air system, a nitrogen generator produces on-site nitrogen providing opportunities for cost savings and energy efficiency for manufacturers who switch from a delivered nitrogen service. With the ongoing shortage of CO2 and a pressure to reduce our industries carbon footprint it makes sense that more companies would be looking into on-site nitrogen generation.

Most nitrogen generators rely on either pressure swing absorption (PSA) or membrane technology to achieve the nitrogen purity level.

Pressure Swing Absorption

Pressure Swing Absorption or PSA Generators use compressed air to create a continuous nitrogen stream. PSA technology incorporates carbon molecular sieves (CMS) that adsorb oxygen molecules from the compressed air. As the air flows over the CMS, oxygen and other particles are caught in the sieves, but the nitrogen is able to pass through into a tank. These types of generators typically feature two connected towers that work in tandem to produce an almost continuous flow of nitrogen gas.

PSA nitrogen generators can provide higher gas purities of up to 99.999% for flows up to 685cfm, making PSA the technology ideal for applications that demand the highest purity level.

Membrane Separators

Membrane Separators use porous polymer fibers of various diameters, lengths, efficiencies, and materials to separate the N2 molecules from the others. Gasses pass through the walls of the fibers. Some gasses pass through more easily than others, these gasses include Oxygen, CO2 and water vapor and exhausted to the atmosphere. Nitrogen passes through more slowly, producing a high purity nitrogen steam at the membrane outlet.

Membrane separators have no moving parts, relying solely on the pressure and flow rate of compressed air through the membrane. Because of this membrane generators can only reach purity levels between 95% and 99.5% and flows up to 311cfm.

In conclusion which generator you need, either PSA or membrane will depend on the purity level and flow your application needs. If your application requires the highest purity the PSA generation technology is optimal. If the acceptable oxygen content of your process is greater than 500ppm, a membrane may be the right choice for you.

Interested in learning more about on-site nitrogen generation and PSA and membrane technologies? Visit our site!

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