May. 30, 2025
Liquid nitrogen generators help filter the air in the atmosphere — roughly 21% oxygen and 78% nitrogen — using either Membrane or Pressure Swing Adsorption technologies.
Then it transforms the gas into liquid by compressing and cooling nitrogen gas below its evaporation point of about − 196 °C [− 320 °F].
In this article, we explain why, at Rutherford & Titan, we only carry liquid nitrogen generators with Pressure Swing Adsorption (PSA).
Pressure Swing Adsorption (PSA) Generators use compressed air to create a continuous nitrogen stream.
These generators have two towers filled with Carbon Molecular Sieves (CMS) that are moved by compressed air pumped into the bottom of the active tower.
Then the air passes through the CMS, which adsorbs trace gases, like oxygen, so that the nitrogen can continue moving through the tower. The active tower then vents all accumulated trace gases.
PSA Nitrogen Generators are more effective and are preferred for use when there is a purity requirement of at least 99.5%, resulting in an O2 of 0.5% or less.
Membrane nitrogen generators move compressed dry air through hollow membrane fibers to separate the nitrogen from the other gases.
Oxygen and water vapor are released into the atmosphere, while the nitrogen is redirected to a distribution system for application or storage.
Different membranes can help generate a varying range of nitrogen purity, from less than 90% to 99.9%.
While it is possible to have a high degree of nitrogen purity with these generators, it is typically used when the purity requirement is less than 99.5% with an oxygen level of 0.5% or greater.
At Rutherford & Titan, we favor PSA generators because they guarantee smoother operations and better purity than their counterpart.
The production of liquid nitrogen using a membrane generator can easily be affected by several variables, including flow rate, membrane quantity, membrane size, and pressure.
In other terms, membranes are tubes that can be obstructed by particles and require extremely clean and dry air supply when compared to CBS.
Last, Carbon Molecular Sieves —used in PSA generator — is more effective at removing trace gases because it has narrower pores than the membranes.
With the numerous advantages of producing nitrogen gas on-site, many industrial users are opting for nitrogen gas generators instead of relying on cylinders delivered by vendors.
Nitrogen generators guarantee a consistent supply of high-purity gas as needed, offering safer operation and greater cost-effectiveness due to their utilization of air as the raw material. But how do nitrogen generators work? Let’s dive in.
A nitrogen generator is a device that produces nitrogen gas on-site by separating it from the surrounding air. It ensures a continuous supply of high-purity nitrogen, eliminating the need for traditional cylinder delivery systems.
The vast majority of on-site nitrogen generation systems utilized in industries fall into two broad categories:
Let’s take a look at how they work:
The working principle of a PSA nitrogen generator is that under high pressures, nitrogen gas exhibits a strong affinity for adsorbent media such as Zeolite or Granular activated carbon (GAC). Moreover, various gases can be absorbed from a mixture at different rates, depending on the amount of pressure applied. When the pressure is lowered, the gas is desorbed.
A typical PSA generator set-up comprises two towers – one for absorption and the other for regeneration. Air coming from a compressor enters the absorption tower and contacts the adsorbent which inhibits the nitrogen gas and allows oxygen, carbon dioxide, water molecules, and impurities to pass through. To recover the absorbed N2, we simply reduce the pressure. At any given time, while the adsorption tower is separating the gas, the other is in regeneration mode.
PSA type nitrogen generators are used extensively in food and beverage packaging, electronics manufacturing, chemical industries, medical facilities, wastewater treatment plants and more to separate high-purity nitrogen gas from a compressed air stream.
Nitrogen purity using the PSA technique can be up to 99.999%, depending on the efficiency of the adsorbent and reliability of the overall system.
Nitrogen membrane technology is another efficient alternative to PSA nitrogen systems. It utilizes a high-selectivity membrane for nitrogen gas separation. The material is a semi-permeable layer made of thousands of flexible, cylindrical filaments with pore sizes ranging from 0.03 to 10 microns.
To separate nitrogen gas, dry, compressed air is applied over the material which is housed in a cylindrical vessel (it is essential to use dehumidified air to prevent clogging of the membrane fibers). The membrane allows N2 to pass through but inhibits oxygen, water vapor, inert gases, and air-borne impurities. The selectivity of the membranes is highly dependent on pore size. Membrane type nitrogen generators can generate nitrogen gas with purities up to 99.95% per volume.
Rich offers on-site nitrogen generators suitable for reliable operation in most industrial settings.
Pressure swing absorption and membrane nitrogen generators are reliable systems capable of producing high-purity (up to 99% per volume) nitrogen gas. The main difference is in the mode of operation (PSA systems utilize adsorbents while membrane systems utilize hollow fiber membranes). Industrial users can choose from these two options based on cost considerations, quality, and efficiency.
Rich offers both skid-mounted membrane nitrogen and PSA generation systems for industry. For short-term use, consider one of our nitrogen generator rentals.
Below are some benefits of using PSA and membrane nitrogen generators.
Generating nitrogen on-site saves industrial users from operational downtime because of nitrogen gas needs. Downtime due to logistics issues with trucking compressed nitrogen gas cylinders from vendor locations incurs huge time and financial losses for industrial users every year. In contrast, having an on-demand nitrogen generation system in place ensures that you have a 24-hour supply of high-purity gas for your processes.
Generating nitrogen on-site proves more cost-effective than purchasing it from vendors, primarily due to savings on transportation and storage costs. This cost advantage is particularly pronounced for membrane nitrogen generators compared to PSA systems. Transporting nitrogen gas between locations necessitates the involvement of internal logistics teams or external trucking companies, which charge for freight services.
Additionally, industrial operators may need to allocate space for storage facilities on-site, subjecting their businesses to compliance with storage standards for compressed cylinders. There’s also a risk of product loss during transit, especially if temperatures fluctuate. Rich offers high-purity on-site nitrogen generators for rent at competitive rates within the industry.
On-site nitrogen gas generation systems offer enhanced safety compared to nitrogen gas from cylinders. Leaks from damaged cylinders can release toxic levels of nitrogen, especially in confined spaces. Utilizing PSA or membrane filtration systems reduces the need for cylinder storage, minimizing associated risks.
Rich’s high-purity on-site nitrogen generators provide a reliable and cost-effective solution, ensuring uninterrupted operations and enhanced safety. Contact us today to learn more about how our nitrogen generation systems can benefit your business.
Since , Rich has been at the forefront of cutting-edge design and manufacture of on-site nitrogen generation systems. In addition to permanent sales, we offer industrial air equipment rentals to a variety of industries. Additionally, we provide field and pipeline maintenance services for industrial and O&G users.
