Due to its inert nature, gaseous nitrogen can be used in various purging, blanketing, and flushing operations. Depending on the process involved, different grades of nitrogen purity are needed to fulfill unique manufacturing needs.

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This article discusses the categories of nitrogen gas for industrial use and their appropriateness for different manufacturing processes.

What Is Nitrogen Purity?

Nitrogen purity refers to the proportion of nitrogen gas present in a sample taken from its stream compared to impurities present. Nitrogen gas can be categorized as high purity or low purity depending on the ratio of pure gas to contaminants like oxygen, water vapor, carbon monoxide, and carbon dioxide.

This categorization based on nitrogen concentration plays a key role in determining the suitability of nitrogen for any industrial process.

High-Purity vs. Low-Purity Nitrogen

The purity of a sample of nitrogen gas is determined by the percentage/concentration of pure nitrogen in it. For gas to be classified as high purity, it must possess at least 99.998 percent nitrogen while lower purity nitrogen gas usually contains a higher proportion of impurities.

High-Purity Nitrogen Gas

Gaseous nitrogen with concentrations above 99.998% is considered a high-purity fraction. High nitrogen purity can be graded in different ways by different manufacturers; however, it is mostly considered to be a 'zero-grade' fraction. Zero-grade nitrogen purity is categorized as such because it contains less than 0.5 parts per million of hydrocarbon impurities.

Other key characteristics of high-purity nitrogen gas are:

• Oxygen concentration ' 0.5 parts per million
• Carbon monoxide/carbon dioxide no more than 1.0 parts per million
• Water not greater than 3 parts per million

Low-Purity Nitrogen Gas

Nitrogen gas ranging between 90 to just under 99.9% is considered to be low-purity. Common low-purity nitrogen gas brands include:

• Zero
• Pre-purified
• Oxygen-free
• Extra dry
• Industrial

How to Check the Purity of Nitrogen Gas

Nitrogen gas manufacturers name their products differently; there are no standardized naming conventions. As a result, a low-purity gas from one producer might be mistaken for a high-purity gas by another based on its name alone. The only definitive way to determine a gas rating is to check the manufacturer's guide on their unique gas concentrations.

Nitrogen Gas Purity Classification

Classifying pure nitrogen gas is done with the grading system using digits within each minimum purity rating. The first digit of each grade refers to the number of 'nines' present in it while the second digit represents the number following the last nine. For example, grade N3.0 is equal to 99.9% nitrogen purity and is a pure grade gas purity classification (no second digit attachment).

Pure grade nitrogen classifications include N2.0, N3.0, N4.0, N5.0, N6.0, and N7.0.

What Is Ultra High Purity (UHP) Nitrogen Gas?

Ultra-high nitrogen purity levels refer to a nitrogen gas concentration of 99.999% with negligible impurities. UHP nitrogen specifications are strict with variations rendering the classification invalid.

The oxygen content of UHP gas can be no greater than 2 parts per million by volume (ppmv), total hydrocarbons cannot exceed 0.5 parts per million by volume, and moisture no greater than 1 part per million by volume). UHP nitrogen gas is typically used in scientific applications.

What Is Oxygen-Free Nitrogen (OFN)?

Oxygen-free nitrogen is defined as gaseous nitrogen containing no more than 0.5 parts per million of oxygen. OFN gas is typically maintained at 99.998% nitrogen purity. This grade of nitrogen gas is useful in scientific research and calibration processes where oxygen impurities might alter outcomes or cause incorrect results.

Nitrogen Purity Grades by Industry

As mentioned above, the concentration of nitrogen required in different industrial processes varies greatly. The key consideration in choosing a grade of nitrogen is the effect of impurities on the selected application. Sensitivity to moisture, oxygen, and other contaminants are critical factors to consider

Pharmaceutical-Grade Nitrogen

Pharmaceutical manufacturing processes require high nitrogen purity levels to prevent contamination and alteration of their final products. Many drugs require high-grade nitrogen with a purity between 97-99.99%. This high to ultra-high purity nitrogen is used for nitrogen blanketing storage tanks, receptacles, and other equipment used in drug manufacturing.

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High-purity nitrogen is also used in drug packaging to help retain freshness and keep active ingredients from deteriorating.

O&G-Grade Nitrogen

Gaseous nitrogen with purity levels ranging from 95-99% is useful in the oil and gas industry to reduce the risk of fires and explosions in associated processes. Chemical storage tank inerting and pipeline purging with gaseous nitrogen help minimize the risk of sudden combustion of their contents.

Pipeline maintenance services frequently use pressurized nitrogen for pipeline cleaning and pipeline decommissioning processes.

Food-Grade Nitrogen/Beverage Grade Nitrogen

Nitrogen is commonly used in different steps of food/beverage production, packaging, and storage.  Nitrogen in food packaging and processing is used to preserve the shelf life of processed food/drinks by eliminating food oxidants, preserving flavor, and preventing rancidity. Food-grade nitrogen gas requirements typically fall between 98-99.5% purity.

Industrial Nitrogen Grade Purity

Understanding the nitrogen grade requirements for each application is essential for selecting the appropriate nitrogen supply source and ensuring optimal performance and reliability. Some industrial applications and their nitrogen-grade requirements are outlined below.

• Electronic & Semiconductor Manufacturing Grade Nitrogen ' The typical nitrogen grade requirements in electronics and semiconductor production are usually at least 99.99-99.999%. Some processes, like parts cleaning and adhesive blanketing, utilize lower concentrations of nitrogen (95-99.5%).
• Plastics Manufacturing Grade Nitrogen ' Nitrogen grade requirements for plastics synthesis is 95-98% for injection molding processes, 99.5% for gas-assist injection molding, and 98-99.5% for blown film extrusion.
• Metalworking Grade Nitrogen ' Metalworking grade nitrogen varies widely from 95-99% for heat treatment to 99-99.999% for laser cutting processes.
• Power Generation Grade Nitrogen ' Power generation processes like gas seal purging, boiler layup, natural gas line purging, and demineralized water blanketing require nitrogen gas with purities between 95-99.6%.

NiGen's Onsite Nitrogen Generators Cover Most Applications

At NiGen, we specialize in supplying and maintaining efficient onsite nitrogen generators tailored to meet the diverse needs of various industrial manufacturing processes. With our extensive range of products and services, we ensure that all nitrogen requirements are fulfilled at every stage of your production cycle.

Contact us online today for a quote or to learn more about our services and nitrogen generators.

Nitrogen Generator Purity Levels By Industry

Nitrogen gas is one of the most commonly used industrial gases across various industry applications. Its inert properties make it virtually undetectable to the senses. That also means it can safely come into contact with virtually any product or surface and prevent contamination or combustion of flammable and explosive materials by eliminating reaction with oxygen in ambient air. Used for blanketing, flushing, and purging industrial equipment, nitrogen gas also retains the freshness of packaged food products and guarantees a much longer and more sustainable shelf life.

Different grades and purity levels of nitrogen gas are required to achieve these objectives. Onsite nitrogen generators ensure a consistent supply of nitrogen gas at just the right purity for the specific application. Onsite nitrogen generator purity levels must be maintained according to the specific requirements of the industrial application for which it's being used. Keep reading to learn about the different industrial applications nitrogen is used for and the purity levels each one requires.

What Is Nitrogen Gas Purity?

Nitrogen gas purity levels are determined by the percentage or concentration of pure nitrogen gas that's found in the nitrogen gas process stream. For nitrogen to be considered completely pure, it needs to have a concentration of 99.999%+. Its purity classification is determined by the ratio of pure nitrogen gas compared to the presence of potential contaminants that includes water vapour, oxygen, carbon dioxide, and argon. Each of these elements can lower the purity level of the nitrogen gas and may render it unsuitable for certain industrial applications.

How Does the Nitrogen Gas Purity Classification Process Work?

Nitrogen gas that's produced using onsite generators is immediately analyzed to determine the purity levels before it's allowed to enter the facility's pipe network. This process ensures that the nitrogen purity levels are sufficiently graded to perform the tasks or processes for which the gas is intended.

An internal instrument known as an oxygen sensor or analyzer is utilized to determine the nitrogen purity levels and display the nitrogen purity number in real time to give an accurate reading. The oxygen sensor or gas analyzer presents a specific value that represents nitrogen purity as a percentage of nitrogen or parts per million of oxygen in the nitrogen gas stream.

Types of Nitrogen Purity Levels

Nitrogen purity ratings may vary according to each manufacturer's discretion. High purity nitrogen gas is usually classified as zero grade or N5.0. This means that the nitrogen contains an extremely low concentration of impurities such as water vapour, oxygen, argon, carbon dioxide or hydrocarbons.

There are different N ratings for different nitrogen purities. For example, a grade of N3.0 translates to a 99.9% purity rating. The first digit, which is the 3, indicates that there are three nines in the reading and the second digit, the 0, indicates that there are no other digits that follow the last 9.

Ultra-High Purity (UHP) Nitrogen Gas

Ultra-high purity (UHP) nitrogen gas has an extremely high concentration of 99.999% with only 10 ppm of oxygen present. The impurity levels are so minimal that they're completely negligible and have no bearing on the quality or efficacy of the nitrogen gas. Since UHP nitrogen gas has such a high concentration with an inconsequential quantity of impurities such as oxygen, water vapour/moisture, and hydrocarbons, it's most commonly reserved for scientific processes and applications.

Low Purity Nitrogen Gas

When nitrogen gas has a purity rating of 99.9% or lower, then it's typically considered to be low-purity or low-grade nitrogen. Purity grades and criteria typically vary by industry application, but low purity nitrogen can also be branded as industrial quality nitrogen.

Required Nitrogen Generator Purity Levels for Various Industries

Nitrogen purity level requirements vary from one industry application to another. Here are the general purity level requirements for some of the top industries in the world.

• Heat Treating Industry: For heat treating metals, typical nitrogen purity levels need to be between 99.9% and 99.999%
• Laser Cutting Industry: Laser cutting processes typical nitrogen purity requirements can range from as low as 97% to 99.995%+ depending on metals being cut.
• Food and Beverage Industry: Nitrogen is widely used for a variety of applications in the food and beverage industry from production and packaging to storage. Food-grade nitrogen gas usually requires a nitrogen purity of 99% to 99.9%. The use of nitrogen helps extend the shelf life of packaged foods, preserves flavour, and prevents spoilage.
• Pharmaceutical Industry: During the production and storage process, pharmaceutical or prescription drugs require a high medical-grade nitrogen concentration with a purity rating range of 97% to 99.999% to blanket storage tanks and other equipment used in the manufacturing, transportation, and storage process.
• Oil and Gas Industry. Nitrogen purity levels range between 95% and 99% to maintain or increase safety standards and prevent catastrophic events like explosions or fires during the processing of oil and gas. Nitrogen gas is used to purge pipelines and chemical storage tanks to minimize or eliminate the risk of spontaneous combustion in oil and gas rigs.
• Power Generation Industry. Processes such as natural gas line purging, gas seal purging, boiler layups, and demineralized water blanketing need a nitrogen gas purity level of 95% to 99.9%.
• Electronics manufacturing industry. Electronic and semiconductor manufacturing facilities require nitrogen purity levels ranging from 99.9% to 99.999%. Lower purity concentrations of 95% to 99.5% can be used for processes like cleaning and blanketing adhesives.

Advanced Gas Technologies PSA and Membrane Nitrogen Generators

Considering the ubiquity of nitrogen gas across various industrial sectors, it makes practical, environmental, and financial sense to install onsite nitrogen generators that are capable of providing a steady stream of nitrogen gas with varying purity levels for different applications. Advanced Gas Technologies provides state-of-the-art PSA and membrane nitrogen gas generators that feature adjustable nitrogen purity settings to suit your application requirements. Contact us today to learn more.

Contact us to discuss your requirements of Lab Nitrogen Generator​. Our experienced sales team can help you identify the options that best suit your needs.