Nitrogen, considered the "fifth largest utility" in industrial production

Nitrogen, considered the "fifth largest utility" in industrial production, is as important as water, electricity, natural gas, and compressed air, and is widely used in various industrial scenarios. Currently, there are two main ways to obtain nitrogen: one is by relying on third-party suppliers (such as cylinder gas, liquid nitrogen, and on-site cryogenic air separation), and the other is on-site in-house nitrogen generation. With the increasing demands for cost reduction and efficiency in industry, on-site nitrogen generation has become the mainstream market trend. Atlas Copco, leveraging its expertise in gas equipment, can provide customized on-site nitrogen generation solutions based on a company's specific purity and flow rate requirements, helping companies control costs while maximizing nitrogen quality. This article will guide you through the development trends, core advantages, technical principles, and industry applications of on-site nitrogen generation, providing a reference for your nitrogen supply solution selection.

The traditional model of relying on third-party nitrogen suppliers (such as gas cylinder storage and liquid nitrogen storage tanks) has many pain points: logistics and transportation have a heavy environmental burden, employees need to spend time managing the supply chain, gas is easily wasted, there are safety risks, and the total long-term cost is high.

On-site nitrogen generation can perfectly solve these problems, and its core advantages can be summarized in 6 points:

1. Lower cost: The unit nitrogen production cost is only a fraction of that of third-party suppliers, resulting in significant long-term benefits;
2. Costs are controllable: there is no need to sign long-term and complex third-party supply contracts, and costs are stable and predictable;
3. Zero waste: Nitrogen production is directly proportional to usage, and there will be no idle or wasted gas.
4. Reduce management costs: Eliminate processes such as nitrogen transportation, order processing, and payment reconciliation, reducing the amount of management effort required;
5. Safer: No need to store large amounts of high-pressure gas cylinders or liquid nitrogen on-site, reducing safety hazards in the working environment;
6. Low environmental impact: Reduces carbon emissions during transportation and eliminates the need for resource-intensive storage containers.

For companies with a stable daily nitrogen demand, on-site nitrogen generation is undoubtedly a better choice, as it can improve operational efficiency from multiple dimensions such as supply chain, cost, and safety.

On-site nitrogen generation mainly relies on two core technologies: membrane separation technology and pressure swing adsorption (PSA) technology. The two have different principles and applicable scenarios, and can be flexibly selected according to the needs of enterprises.

The core component of membrane separation nitrogen generation is the "membrane module" (approximately 10 cm in diameter), which is filled with a large number of hollow polymer fibers. The nitrogen generation process can be summarized as "permeation separation."

• After dry and clean compressed air enters the membrane module, different components in the air will pass through the polymer fiber wall at different speeds due to differences in molecular properties (this process is called "osmosis").
• Water molecules (H₂O) permeate the fastest and are the first to pass through the fiber wall and be expelled; oxygen molecules (O₂) permeate the second fastest and are expelled later.
• Nitrogen (N₂) molecules have the slowest permeation rate and cannot pass through the fiber wall. They eventually remain inside the fiber and flow out from the other end of the membrane, becoming usable nitrogen gas.
• To prevent unpermeable gases from creating overpressure and clogging the fibers inside the membrane shell, the membrane shell is equipped with "permeation vents" to promptly discharge "waste gases" such as water and oxygen.

• The intake air must be clean and dry: If the compressed air contains liquid water or impurities, it will clog the diaphragm fibers and shorten its service life. Therefore, a water separator (such as a refrigerated dryer) needs to be installed upstream of the nitrogen generator. Some models already have built-in filters and dryers, so no additional installation is required.
• A small amount of water vapor is permissible: The membrane fibers can tolerate a certain amount of water vapor, so there is no need to over-treat the intake air humidity, but liquid water must be absolutely avoided from entering.

PSA nitrogen production is based on an "adsorption-regeneration" cycle. The core components are two pressure vessels (tower A and tower B) containing "carbon molecular sieves." Continuous nitrogen production is achieved by switching the operating states of the two towers.

• Adsorption stage: Dry and clean compressed air enters tower A, and the carbon molecular sieve will preferentially adsorb impurities such as oxygen (O₂), carbon dioxide (CO₂), and water vapor (oxygen molecules are smaller and can enter the molecular sieve pores, while nitrogen molecules are larger and cannot enter); the unadsorbed nitrogen is discharged from tower A and can be used or stored directly.
• Regeneration stage: When tower A is saturated with adsorption, the system switches to tower B (tower B enters the adsorption stage and continuously produces nitrogen); at the same time, a small amount of nitrogen discharged from tower A will flow back into tower A, reducing the pressure inside tower A. After the pressure drops, the carbon molecular sieve will release the previously adsorbed oxygen, which will be carried away by the reverse nitrogen and discharged.
• The two towers alternate between adsorption and regeneration to achieve continuous and stable nitrogen production for 24 hours. The Atlas Copco NGP+ series nitrogen generator uses PSA technology and is a "plug-and-play" device that is simple to operate and highly reliable.

• Intake air requires thorough treatment: Compressed air must undergo drying, oil removal, and dust removal—if it contains oil or moisture, it will contaminate the carbon molecular sieve, leading to a decrease in adsorption capacity. Therefore, a dryer, oil filter, and carbon filter must be installed between the compressor and the nitrogen generator.
• Add fault protection: It is recommended to install pressure, temperature and pressure dew point sensors in the nitrogen generator. If the intake air does not meet the requirements, an alarm can be set in time to avoid contaminating the PSA system.

Nitrogen gas, due to its inert (low reactivity) and colorless and odorless properties, is suitable for a variety of industrial needs. The following are its main application scenarios:

• Core function: To replace oxygen in the packaging, prevent food from oxidizing and spoiling, and maintain the taste and aroma of the product; at the same time, to extend the shelf life of packaged foods (such as potato chips, baked goods, and beverage bottling).

• Core function: In the process of drug production and packaging, dry nitrogen creates an "inert environment" to prevent oxygen from causing unnecessary chemical reactions in drugs and to ensure drug quality; at the same time, it helps pharmaceutical companies reduce gas procurement costs and meet industry compliance standards.

• Core function: Electronic components have extremely high requirements for the production environment. Nitrogen can be used in welding, assembly, storage and other processes: it prevents component oxidation during welding, creates a clean and controlled environment during assembly, avoids moisture damage during storage, and ultimately reduces the defect rate.

• Core function: In analytical techniques such as LC-MS (liquid chromatography-mass spectrometry), nitrogen is used to remove solvents from the sample to avoid solvent interference with measurement results; at the same time, it can form a neutral protective environment to ensure the accuracy of experimental data.

• Core function: Improve operational safety – Use nitrogen to purify compressor systems, pipelines, and reactors, and discharge flammable and explosive gases to prevent fires or explosions; it can also be used for defoaming in oil storage tanks and pressure control during oil and gas drilling.

• Core function: Nitrogen can reduce the oxygen concentration in the environment to below the "limited oxygen concentration (LOC)," preventing flammable substances from burning due to insufficient oxygen. It is one of the key technologies for industrial fire safety worldwide.

• Core functions: Covering industries such as automobile manufacturing, construction, metal processing, aerospace, battery production, and renewable energy, it is mainly used in scenarios such as anti-oxidation, pressure control, and environmental protection (such as inert protection during metal heat treatment and moisture protection during battery production).

If you need further information on on-site nitrogen generation solution selection (such as specific application scenarios for PSA and membrane separation technologies), or would like to obtain stomized nitrogen demand calculations, please leave a message in the comments section. You can also obtain more technical information through Atlas Copco's official channels.