Nitrogen is widely used across industries for applications such as inerting, purging, and protecting products and processes from oxygen exposure. Depending on the application, businesses may need nitrogen at different levels of purity, flow, and pressure.

Nitrogen can be supplied in cylinders, bundles, or bulk systems, or produced directly at the facility using a nitrogen generator. On-site nitrogen generation allows facilities to produce nitrogen from compressed air and supply it directly to the point of use.

But what is a nitrogen generator, and how does it work? Let us break it down in this blog.

What Is a Nitrogen Generator?

A nitrogen generator is a device that separates nitrogen (N₂) from compressed air to produce nitrogen gas for industrial processes. It does not create nitrogen from scratch. Instead, it uses air as the feedstock and isolates nitrogen from other gases using technologies such as Pressure Swing Adsorption (PSA) or membrane separation.

An on-site nitrogen generator can therefore provide nitrogen at the point of use, reducing dependence on delivered cylinders, bundles, or bulk supplies.

The required nitrogen purity depends on the application. For example, some processes need nitrogen for inerting or tyre inflation, while others require high-purity nitrogen for laser cutting, food packaging, electronics, or pharmaceutical applications. A suitable nitrogen generation system must therefore be selected according to the required purity, flow, pressure, duty cycle, air quality, and operating conditions.

How Does a Nitrogen Generator Work?

Compressed air is treated, separated, and monitored before the nitrogen reaches the application.

1. Compressed Air Intake

A nitrogen generator uses compressed air as its feed gas. A compressor supplies air at the pressure required by the generator, after which the air enters the pretreatment and separation stages.

This is why the quality of the feed air matters. Depending on the compressor and generator design, the air may require particulate and coalescing filtration, oil removal, condensate separation, and drying before it enters the separation stage. This pretreatment helps protect the separation media and supports consistent nitrogen production.

2. Filtration and Drying

Before nitrogen is separated from the air, contaminants such as moisture, oil, water, and particles are removed through filtration and drying.

The separation stage can only perform as well as the air entering it. Poor air quality can affect the separation process and the quality of the nitrogen produced.

3. Separation Stage: PSA or Membrane

For many on-site nitrogen generators, the two main non-cryogenic separation methods are PSA and membrane separation.

• Pressure Swing Adsorption (PSA): In a PSA nitrogen generator, compressed air passes through a carbon molecular sieve (CMS), which preferentially adsorbs oxygen and other gases while allowing nitrogen to pass through as the product gas.
• Membrane separation: A membrane nitrogen generator uses selective permeation. Compressed air passes through hollow-fibre membranes, where oxygen, water vapour, and other faster-permeating components pass through the membrane more readily than nitrogen.

4. Purity Monitoring

The produced nitrogen is monitored to confirm that it meets the required specification. The nitrogen purity monitoring method may vary between systems. Some generators may use an oxygen analyser to measure residual oxygen in the nitrogen stream.

NITROGAS NG, for example, uses a zirconium oxide oxygen analyser to continuously measure residual oxygen content in the nitrogen stream.

5. Delivery of Nitrogen on Demand

Depending on the system design, a buffer vessel can store a supply of nitrogen and help manage short-term changes in demand, while the generator continues producing nitrogen to the required specification.

This creates a controlled on-site nitrogen gas generation process, with production matched to the facility's requirements.

Types of Nitrogen Generators

PSA Nitrogen Generators

A PSA nitrogen generator uses alternating adsorption and regeneration cycles to extract nitrogen from compressed air. In a typical two-bed system, one tower adsorbs oxygen under pressure while the other is depressurised and regenerated. The beds then alternate to maintain a continuous product supply. PSA technology is commonly selected when an application requires higher nitrogen purity, controlled flow or a more tightly specified product stream.

Membrane Nitrogen Generators

A membrane nitrogen generator enables nitrogen production through the membrane itself rather than by adsorption. The system passes compressed air through bundles of hollow polymer fibres. Oxygen, water vapour, and other faster-permeating components pass through the membrane more readily, while nitrogen remains in the product stream. These systems can offer a compact solution for applications that require continuous flow, moderate nitrogen purity, and simple operation.

Nitrogen Generator Applications

Nitrogen generators can be used across industries where nitrogen is required regularly and in a controlled supply. They can be a practical and cost-effective alternative to delivered nitrogen where the required gas can be produced on site and supplied directly to the process.

Common applications include:

Laser cutting

In some laser-cutting applications, nitrogen is used as an assist gas to reduce oxidation at the cut edge and support a cleaner finish.

Food packaging

Nitrogen is used in modified atmosphere packaging (MAP) and flushing applications to displace oxygen and help protect product quality.

Winemaking

Nitrogen can be used for blanketing and inerting to reduce oxygen exposure during production and storage.

Beverage production

Nitrogen can support tank blanketing, line purging, packaging and other applications where oxygen exposure needs to be controlled.

Chemical and pharmaceutical manufacturing.

Nitrogen is used for purging, blanketing, and maintaining controlled atmospheres around oxygen-sensitive materials and processes.

Metal fabrication

Nitrogen is used in selected cutting and heat-treatment processes where oxidation control and surface quality are important.

Other applications

Electronics manufacturing, automotive processes, and tyre inflation can also use nitrogen where controlled gas quality or reduced oxygen exposure is required.

Benefits of Using Onsite Nitrogen Generators

Why produce nitrogen on site? The answer depends on the facility, but several benefits are common.

• Safety: Onsite generation can reduce the need to handle and store high-pressure nitrogen cylinders or cryogenic tanks.
• Reliability: Nitrogen is produced at the facility, reducing dependence on delivery schedules and external suppliers.
• Cost savings: Generating nitrogen onsite can reduce costs associated with cylinder rental, gas delivery and handling. The actual savings depend on consumption and operating conditions.
• Flexible scalability: Modular nitrogen generation systems can provide a practical way to adapt capacity as demand changes.
• Sustainability: Reducing delivered-gas logistics can help reduce the transport-related environmental impact of nitrogen supply.

For facilities considering on-site nitrogen generation, choosing the right system starts with understanding the required purity, flow, pressure, demand profile and application.

Why NITROGAS NG?

Built around PSA technology, it provides an automatic, on-demand supply while PLC supervision monitors key parameters such as purity, pressure and flow. A zirconium oxide oxygen analyser continuously measures residual oxygen to monitor nitrogen purity.

Its compact, modular design can grow with the facility, while Industry 4.0 compatibility, proprietary software and complete installation support help keep day-to-day operation straightforward.

For facilities moving away from traditional nitrogen supply, this can also make a significant difference to the cost of keeping nitrogen available. NITROGAS NG can reduce total nitrogen costs by up to 90%, depending on the application and existing supply arrangement, while reducing reliance on cylinders, deliveries and external suppliers.