How to check nitrogen purity for optimal performance
Nitrogen gas plays a vital role across industries, from food preservation to precision manufacturing. However, different applications require different purity levels — and exceeding those needs can lead to unnecessary costs.
This guide aims to support businesses in finding the right balance between purity levels and operational efficiency.
Industries such as food packaging, laser cutting, and electronics manufacturing rely on nitrogen for daily operations. But not all nitrogen is created equal. Knowing how to check nitrogen purity helps businesses comply with industry standards, optimize quality, and avoid excessive costs.
Ensuring the right nitrogen quality — including purity and absence of contaminants — safeguards performance, safety, and product integrity. Here we explain how to check nitrogen purity, what standards apply, and how on-site generation ensures consistent, cost-effective results.
What does nitrogen purity mean and why does it matter?
Purity refers specifically to the concentration of nitrogen in the gas, meaning how much of the gas is composed of nitrogen versus other elements or compounds. For example, 99.999% nitrogen purity means only 0.001% of other gases are present. The cost of nitrogen generation increases with higher purity requirements. Higher purities require more compressed air, more energy, and often a bigger compressor and gas generator. Higher purity comes at a price.
Getting nitrogen purity right allows for a smaller compressor and generator with lower investment, maintenance, and energy costs. Good news: This is true for the majority of gas applications, and most companies can save a lot of money on gas generation. The freedom to control purity and costs contrasts with purchased gas, which has a fixed purity due to its production process.
High purity vs. cost
While N2 5.0 (99.999% purity nitrogen) can be necessary for labs or medical use, but not every operation requires that level. Choosing the right purity — and avoiding over-specification — saves significant costs in energy and system complexity. Some industries can optimize costs by using lower purity levels. The cost difference between 95% and 99.999% nitrogen can be substantial, primarily due to the energy required for additional purification.
The Atlas Copco Nitrogen Purifier through Hydrogen (Deoxo System) introduces a new, more cost-efficient way to produce very high-purity nitrogen: two-stage generation. Working in tandem with a nitrogen generator, the NPH boosts low-purity nitrogen to 99.999% and higher while reducing feed air consumption by 40%.
What does nitrogen quality mean and why does it matter?
Quality is a broader term that includes not just purity but also the presence of contaminants like moisture, oil, and particulates. A nitrogen supply with high purity could still have quality issues if it contains unwanted contaminants. These impurities are removed using best in class filters and dryers from Atlas Copco. Ensuring both high purity and good quality gas is essential for industries that rely on nitrogen for sensitive applications.
Different industries require different nitrogen purity levels
Choosing the correct purity level is essential, as higher purity levels demand more energy and filtration, increasing costs unnecessarily when ultra-high purity nitrogen isn't required.
Purity level
|
Applications
|
Purpose
|
99.5%
|
Food and beverage packaging
|
Prevents oxidation and extends shelf life.
|
99.99%
|
Laser cutting and metal processing
|
Ensures precision cutting with minimal oxidation.
|
99.999%
|
Electronics and pharmaceuticals
|
Protects sensitive components from contamination.
|
Note: For pharmaceutical and medical uses, Nitrogen NF must meet strict U.S. Pharmacopeia (USP) or European Pharmacopoeia standards for both purity and handling.
The term "Nitrogen NF" (N2 NF) refers to nitrogen that meets the National Formulary standard, commonly used in medical and pharmaceutical settings where ultra high purity is essential.
How to check nitrogen purity
Ensuring high nitrogen purity requires regular monitoring with specialized tools. In a nitrogen generator, the most common method is using oxygen sensors to measure residual oxygen content.
Rather than directly measuring nitrogen content, the generator uses sensors to detect the small amount of oxygen that remains after the gas separation process. The lower the oxygen content, the purer the nitrogen. Integrating oxygen sensors into your system helps maintain consistent nitrogen quality.
Factors affecting purity
- Operating pressure: The pressure at which the nitrogen generator operates can influence the purity of the nitrogen produced. Higher pressures can improve the separation efficiency of nitrogen from other gases.
- Temperature: The temperature of the feed air and the operating environment can impact the performance of the nitrogen separation process. Proper temperature control is essential to maintain desired purity levels.
- Flow rate: The flow rate of the feed air through the nitrogen generator affects the separation process. Adjusting the flow rate can help achieve and maintain the required nitrogen purity.
- Feed air quality: The quality of the compressed air used in the nitrogen generator is crucial. Contaminants such as water vapor, oil, and particulates must be removed before the air enters the separation process to ensure high purity nitrogen.
- Membrane module configuration: The arrangement and number of membrane modules can affect the purity in membrane-based nitrogen generators. Proper configuration and maintenance of these modules are necessary for optimal performance.
- Adsorbent material: In pressure swing adsorption (PSA) systems, the type and condition of the adsorbent material (e.g., carbon molecular sieve) play a significant role in determining the purity of the nitrogen produced.
- Valve positions and function: Proper positioning and functioning of valves within the nitrogen generator system are essential to control the flow and pressure, thereby affecting the purity.
- Ambient conditions: External factors such as ambient temperature and humidity can influence the nitrogen generation process and its purity.
- Maintenance and calibration: Regular maintenance and calibration of the nitrogen generator and its components are necessary to ensure consistent purity levels.
How on-site nitrogen generation ensures cost-effective purity
Traditional bulk nitrogen supply involves storage, transportation, and vendor dependency, which can increase costs and introduce purity inconsistencies. On-site nitrogen generation offers more control and consistency.
Key technologies:
PSA generators:
Provide adjustable settings, including n2 5.0 for ultra high purity
Membrane generators:
Ideal for lower-purity needs (up to 99.5%), with lower energy consumption
Benefits:
Eliminate supplier inconsistencies
Maintain consistent N2 purity for your specific process
Reduce operational costs by generating only what you need
Avoid delays or supply chain issues
Monitoring nitrogen purity and matching it to your application can prevent waste and ensure compliance with industry standards such as Nitrogen NF. Choosing the right testing methods and understanding cost trade-offs is key. For many businesses, on-site nitrogen generation is the smartest way to maintain reliable, cost-effective purity — without compromising performance.
Looking to optimize your nitrogen purity and reduce costs? Discuss options with our experts today.
Related topics
