In many industries, a reliable supply of nitrogen gas is far more than a luxury, it’s essential.
It plays a key role in everything from keeping food fresh to preventing oxidation in metalwork.
Traditionally, having a steady supply has meant relying on shipping in high-pressure cylinders or bulk liquid tanks. But that route comes with its inevitable downsides – high logistical costs, supply chain delays, and unnecessary extra safety risks.
On-site nitrogen generation offers a smarter alternative.
Instead of relying on external suppliers, you can produce nitrogen where you need it. And to be clear, it’s not that a nitrogen generator creates nitrogen; it separates it from the atmosphere around us.
Compressed air is the starting point for all on-site nitrogen generation – and that’s why all nitrogen gas systems begin with clean, dry, compressed air.
It All Starts With Clean Air
First things first, your nitrogen generator is only as good as the air going into it.
A nitrogen generator is a sophisticated piece of equipment, but it’s just one downstream component of a much larger system.
There are a number of different types of air compressors, but whether you’re using a screw or piston compressor, the key is clean, dry air. Without it, your system won’t last long.
Why? Because the act of compression concentrates three contaminants present in ambient air that are destructive to any nitrogen generator:
- Water: Even small amounts of moisture can seriously affect the material inside PSA generators or clog up membrane systems.
- Oil: If you’re using a lubricated compressor, oil aerosols can permanently damage the nitrogen separation media.
- Particulates: Dirt, rust, or anything else floating around in the air can easily clog the microscopic passages within a generator and cause it to fail.
That’s why, if you want to properly protect your investment, a proper air treatment system is a must-have. This ensures the generator receives air that meets a specific purity standard, often defined by ISO 8573-1:2010 air quality classes.
To protect your equipment and keep everything running smoothly, you’ll need a setup that includes:
- An air receiver to cool the air and remove bulk moisture.
- High-efficiency compressed air filters catch oil and dust.
- An air dryer (refrigerated or desiccant) to strip out any remaining water vapour.
How a PSA Nitrogen Generator Works
For industries that need to go one step further and have access to high-purity nitrogen, Pressure Swing Adsorption (PSA) is the go-to technology.
The idea behind it is simple in its theory, but clever in its execution.
The technique physically separates nitrogen from oxygen and other gases using a material that holds one and releases the other, giving you a steady supply of clean nitrogen while releasing the unwanted gases.
The Principle: Carbon Molecular Sieve (CMS)
At the heart of a PSA nitrogen generator are two identical towers filled with Carbon Molecular Sieve (CMS).
This material has precisely engineered microscopic pores designed to capture or adsorb smaller oxygen molecules under pressure, while allowing the slightly larger nitrogen molecules to pass through. It’s all about size and selectivity.
The Two-Tower Process
To get an uninterrupted, steady flow of nitrogen, the two CMS towers work in a continuous cycle:
- Adsorption: Clean, dry compressed air flows into Tower A. The pressure increases, forcing oxygen into the CMS pores while a stream of high-purity nitrogen gas exits the tower for use or storage.
- Regeneration: Once the CMS in Tower A is nearly full, the system switches. Air is redirected to Tower B. The pressure in Tower A is then released or “swung” down to ambient levels – causing the CMS to release the trapped oxygen molecules, which are then released to the atmosphere.
- Repeat: While Tower A regenerates, Tower B takes over and goes into its adsorption phase and the cycle continues. This perfectly timed switching between the two towers allows for a constant, on-demand nitrogen supply.
Applications and Benefits of PSA Technology
- Purity range: PSA nitrogen generators can deliver gas with a purity level anywhere from 95% right up to 99.999%. This makes them a far more reliable choice for processes where consistency is non-negotiable, such as laser cutting, precision electronics soldering, or pharmaceutical manufacturing.
- Efficiency: When high purity is the goal, PSA technology stands out for its efficiency. It produces more nitrogen per unit of compressed air than many other systems when operating at the upper end of the purity scale.
- Financial case: While the initial investment in a PSA system can be higher, it typically offers the lowest cost per unit of gas over the long term for high-purity requirements. This efficiency and durability often translate into a faster return on investment.
How Membrane Nitrogen Generators Work
Membrane systems are mechanically simpler and extremely reliable, with almost no moving parts. They’re a solid choice when purity demands are lower, but a steady supply is still critical.
Membrane nitrogen generators are ideal for businesses generating their own nitrogen gas on-site with lower purity requirements.
The Principle: Selective Permeation
A membrane generator uses a module containing thousands of tiny, semi-permeable hollow polymer fibres. The wall of each fibre is engineered to allow different gases to pass through, or permeate, at different rates.
The Separation Process
The compressed air, as it flows down the centre of the fibres, is “fast” as the oxygen and water vapour permeate the fibre walls quickly and are vented to safety.
“Slow” nitrogen molecules do not permeate the fibres and so are trapped inside. The gas at the outlet is progressively enriched with nitrogen as the oxygen is removed and the water is vented off.
The process is self-limiting, and the final purity is governed by the flow rate of the compressed air through the fibres. A slower flow rate means the oxygen has more time to permeate, and therefore the outlet nitrogen will be of higher purity but of less volume.
This trade-off between flow and purity is the classic characteristic of membrane technology.
Applications and Benefits of Membrane Technology
- Purity and Use Case: With Purity levels generally limited to a maximum of approximately 99.5% a high purity requirement for specific manufacturing processes is unlikely to be met, and more specialist or costly options will be considered. Perfect purity for mobile systems, offshore rigs, fire prevention, tyre inflation and food processing, etc.
- Simplicity: The absence of moving parts results in ultra-high reliability and very low maintenance.
- Financial Case: A relatively low capital outlay for an attractive, low risk, lower capital investment with huge savings compared to bottled gas in applications where high purity is not an issue
PSA vs. Membrane: Which Technology is Right for You?
The choice between a PSA and a membrane nitrogen generator depends entirely on your specific requirements for purity, flow, and operational cost.
| Feature | Pressure Swing Adsorption (PSA) | Membrane Separation |
| Working Principle | Kinetic adsorption onto Carbon Molecular Sieve (CMS) | Selective permeation through hollow polymer fibres |
| Purity Range | High: 95% to 99.999% | Low to Medium: 95% to 99.5% |
| Energy Efficiency | More efficient for purities above 98% | More economical for purities below 98% |
| Maintenance | Low; requires periodic service of switching valves | Very low; primarily annual filter changes |
| System Footprint | Larger due to twin towers and buffer tank | Compact and lightweight |
| Ideal Applications | Laser Cutting, Electronics, Pharmaceuticals, Metal Heat Treating | Food Packaging, Tyre Inflation, Fire Prevention, Oil & Gas |
Improving Workplace Safety with On-Site Generation
One of the most compelling benefits of on-site nitrogen generation is the profound improvement in workplace safety.
On-site systems produce gas as needed at controlled, lower pressures.
This effectively eliminates the risks associated with traditional supply methods, such as:
- Manual handling injuries from moving heavy, high-pressure cylinders.
- The risk of a damaged cylinder valve causing a catastrophic failure.
- The danger of severe cryogenic burns from handling liquid nitrogen (-196°C).
- Asphyxiation risks from leaks in confined spaces.
Installation & Maintenance: What to Expect
Every on-site nitrogen system is customised to your facility layout, air supply, and usage profile. A typical installation includes:
- Integration with your existing air compressor and compressed air filters
- Compact generator setup for a PSA or membrane system
- Piping to point-of-use with minimal disruption
To maintain long-term performance, we offer preventive maintenance plans including filter replacements, system testing, and support from our Atlas Copco-trained engineers.
With optional SMARTLINK monitoring, you’ll always know how your nitrogen system is performing.
Your Partner for Nitrogen Independence in the UK
Making the switch to on-site generation requires more than just equipment; it demands expert system design, installation, and support.
As a Premier Distributor for Atlas Copco nitrogen generators, J Ll Leach provides complete, turnkey solutions tailored to your operational demands.
Our customers receive comprehensive support from compressed air audits, nitrogen system design, turnkey installation, and preventive maintenance.
Our engineering know-how, developed since 1936 with depots in Stoke-on-Trent, Birmingham and Shrewsbury, will help you ensure your system is as reliable as possible with the lowest cost of ownership.
When you understand how the technology works and have an expert you can rely on to design the entire system from the air compressor through to the point of use, your facility can enjoy supply chain independence and massive operational savings.
Speak to a J Ll Leach specialist today for a no-obligation consultation.
We’ll calculate your potential cost savings, recommend the right system, and handle everything from design to installation.