How Do Nitrogen Generators Work? – Membrane and PSA
Given the numerous advantages of generating nitrogen gas on-site, many industrial users are turning to nitrogen gas generators over the conventional use of cylinders delivered by vendors.
Nitrogen generators ensure a constant supply of high-purity gas on-demand, are safer to operate, and more cost-effective as the raw material it utilizes is air.
If you’re curious about how these machines work, then this article is for you!
What Is a Nitrogen Generator?
A nitrogen generator is a stationary or mobile piece of machinery used to separate nitrogen gas from atmospheric air. 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:
PSA Nitrogen Generator Working Principle
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 utilized 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.
Membrane Nitrogen Generator Working Principle
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.
NiGen offers on-site nitrogen generators suitable for reliable operation in most industrial settings.
Nitrogen Generators – PSA vs. Membrane
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 HFMs). Industrial users can choose from these two options based on cost considerations, quality, and efficiency.
3 Top Benefits of On-Site Nitrogen Generators
Below are some benefits of using PSA and Membrane nitrogen generators.
1. Time Savings
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.
2. Cost Savings
Generating nitrogen on-site is more cost-effective than purchasing the gas from vendors due to savings on the cost of transportation and storage. This is especially true for membrane nitrogen generators (as opposed to PSA systems). Transporting nitrogen gas between locations will require the services of an internal logistics team or trucking companies that charge a fair price for freight.
Industrial operators may also need to provide storage facilities within the site to house the containers. This may also subject your business to storage standards around compressed cylinders. Further, product loss during transit is possible, especially if temperatures fluctuate. NiGen provides high-purity on-site nitrogen generators on a rental basis at some of the best rates in the industry.
3. Safety and Reliability
On-site nitrogen gas generation systems can be safer than nitrogen gas from cylinders. Nitrogen gas leaks from damaged cylinders can be toxic to humans in large, concentrated quantities, particularly when it is present in confined spaces. Using a PSA or membrane filtration system reduces the need for the storage of such containers and can help reduce the associated risks.
Trust NiGen for All Your Industrial Nitrogen Generation Needs
Since 1999, NiGen 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.
To learn more about our services, contact our team online today!