For decades, industrial businesses had to use bottled nitrogen that was supplied by gas companies to power specific applications. Fortunately, this way of doing business is becoming a thing of the past. No longer do businesses have to deal with increasing prices and long contracts. Onsite nitrogen generation is a practical and cost-effective solution for companies in numerous industries, including food, beverage, pharmaceutical, chemical, automobile, aerospace, metal fabrication, electronics, ceramics, glass, and many others.
With nitrogen generators, companies can generate the gas onsite without needing third-party suppliers. That means more production flexibility and no time-consuming ordering or delivery costs. Here’s what you need to know about nitrogen generation technology.
What Is a Nitrogen Generator?
Nitrogen generators don’t actually create the gas. Rather, they are pieces of machinery designed to separate nitrogen that is already present in the air from other molecules. Air composition is 78% nitrogen and 21% oxygen (with small amounts of carbon dioxide, water, and argon). Nitrogen generators provide a constant supply of high-purity nitrogen on demand, are safer than using bottled nitrogen, and are more economical because air is the raw material they use.
How Do Nitrogen Generators Work?
To put it simply, nitrogen generators work by separating nitrogen molecules from oxygen molecules in compressed air, providing a purified nitrogen supply. There are different types of nitrogen generation technologies designed to meet varying purity requirements. For example, if nitrogen is needed for inflating tires or to prevent or suppress a fire, a lower purity level (90%-99%) is sufficient, while higher purities (99.999% or higher) are required for plastic molding or in the food industry.
What Are the Types of Nitrogen Generators?
Most onsite nitrogen generators fall into one of two categories, membrane or pressure swing adsorption (PSA) generators.
Membrane Nitrogen Generators
This type of nitrogen generator pushes compressed air through semipermeable membranes made of bundles of hollow polymer fibers to separate them into component gasses. The hollow fibers are very small, with tiny pores across the surface. Compressed air is introduced into the fibers, and as it contacts the membrane, the oxygen, water, and trace gases pass through the pores and are discharged. Because the nitrogen molecules are larger than oxygen molecules, they do not pass through the membrane. Instead, the nitrogen is contained within the membrane and directed through the outlet port.
Membrane technology is efficient and straightforward. Generators using this type of process are often all-in-one units that are very low maintenance with zero operational costs. They are ideal for applications where the necessary flow of nitrogen is relatively low and required purity levels are under 99%. Typically, nitrogen generators with membrane technology cost less than high-flow, high-purity technologies like pressure swing adsorption.
Pressure Swing Adsorption Nitrogen Generators
PSA nitrogen generators use pressure swing adsorption technology to produce a continuous flow of nitrogen gas from compressed air. This type of generator consists of two towers, or vessels, that are filled with carbon molecular sieve (CMS), which absorb oxygen and other trace molecules during the process. In PSA generators, compressed air is introduced to the bottom of the online vessel and goes up through the CMS. Oxygen is absorbed while nitrogen molecules are allowed to pass through. After a specific, preset amount of time, the online vessel switches to regenerative mode, which vents contaminants from the CMS. Carbon molecular sieve is different than regular activated carbons in that it has a smaller range of pore openings, allowing small molecules (like oxygen) to pass through the openings and become separated from nitrogen molecules which are too big to enter the CMS. The larger molecules of nitrogen bypass the CMS and emerge as the product gas.
PSA nitrogen generators provide users with a higher level of purity, making them ideal for industries that require consistently higher performance levels. They can produce up to 99.999% pure nitrogen gas on a consistent basis, as they are designed to operate at the same flow rates over the course of their operational lifespans. This type of nitrogen generator has a mass flow controller and built-in oxygen analyzer to ensure output purity. They are reliable and are constructed to last for decades.
Final Thoughts about Nitrogen Generation Systems
Whether your industry requires nitrogen gas of very high purity, like that generated from a PSA generator, or it is an industry with lower purity requirements, there is an ideal onsite option that will meet your needs.
At ESA, we are dedicated to providing customers with the tools and technologies they need to operate efficiently and effectively, including nitrogen generation systems. If you would like more information about nitrogen generators, how they work, and which type is right for your business, we can help. Contact one of ESA’s experienced professionals with your questions.
