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.