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Nitrogen generation is the process of producing nitrogen gas on-site from the surrounding air. In the context of compressed air systems, a nitrogen generator takes a clean, dry compressed air supply and separates the nitrogen from the oxygen and other gases, delivering high-purity nitrogen at the required pressure.
On-site generation replaces the traditional approach of purchasing nitrogen in cylinders or bulk liquid deliveries from a gas supplier. For businesses that use nitrogen regularly, generating it on-site can deliver significant cost savings and operational advantages.
High-Purity Nitrogen on Demand
Nitrogen generators can produce nitrogen gas at purity levels typically greater than 99.5%, and in many cases up to 99.999%. The purity level is adjustable to match the specific requirements of the application.
Having a continuous, on-demand supply of nitrogen eliminates the risk of running out at a critical moment. There are no cylinder deliveries to schedule, no rental charges, and no risk of supply chain disruptions affecting your production.
Cost Savings
Purchasing nitrogen from a gas supplier involves the cost of the gas itself, plus delivery charges, cylinder rental, and contract management. These costs accumulate significantly over time, particularly for businesses with high or continuous nitrogen demand.
On-site generation eliminates all of these recurring costs. After the initial investment in a nitrogen generator, the only ongoing cost is the electricity to run the compressed air system that feeds it. For many businesses, the payback period is under two years.
The savings are especially significant for sites that already have a compressed air system in place, as the generator simply connects to the existing air treatment infrastructure.
Improved Efficiency
Nitrogen is an inert gas, meaning it does not react with other substances. When used to purge or blanket compressed air systems and pipework, nitrogen helps to reduce moisture, prevent oxidation, and minimise contamination.
This can extend the life of downstream equipment, reduce the frequency of maintenance and repairs, and improve the overall reliability of the compressed air system.
Better Product Quality
In manufacturing processes where compressed air comes into direct or indirect contact with the product, the quality of the air matters. Nitrogen generation provides a consistent source of high-purity, contaminant-free gas that helps ensure the end product meets the required standards.
Industries that commonly use nitrogen generation include food and beverage (modified atmosphere packaging), pharmaceutical manufacturing, electronics assembly, laser cutting, and chemical processing.
Increased Safety
Nitrogen is non-flammable and non-explosive. Using nitrogen in place of compressed air in certain applications can significantly reduce the risk of fire or explosion, particularly in environments where flammable materials, solvents, or dust are present.
Nitrogen blanketing of storage tanks, for example, creates an inert atmosphere above the stored product, preventing the formation of explosive air/vapour mixtures. This is a well-established safety practice in chemical, pharmaceutical, and petrochemical industries.
How Nitrogen Generators Work
There are two main technologies used in on-site nitrogen generation.
Pressure Swing Adsorption (PSA)
PSA generators use twin towers filled with carbon molecular sieve (CMS) material. Compressed air is fed into one tower, where the CMS preferentially adsorbs oxygen, allowing nitrogen to pass through. When the first tower is saturated, the system switches to the second tower while the first regenerates. PSA generators are well suited to applications requiring high purity and continuous supply.
Membrane Separation
Membrane generators pass compressed air through bundles of hollow fibre membranes. The membranes allow oxygen and water vapour to permeate through the fibre walls, while nitrogen molecules continue through to the outlet. Membrane generators are compact, have no moving parts, and require very little maintenance. They are ideal for lower purity applications and smaller flow rates.
Getting Started with Nitrogen Generation
The feasibility of on-site nitrogen generation depends on your current nitrogen consumption, the purity required, the available compressed air capacity, and the quality of your existing compressed air supply.
Airmech has 45 years of experience in compressed air systems and can assess whether nitrogen generation is a practical and cost-effective solution for your site. Contact us to discuss your requirements and get a detailed cost comparison.