Nitrogen Gas Purity Grades for Different Industry Uses
Like most processed materials, commercially available nitrogen is not 100% pure. It contains at least some trace amounts of other contaminants. This is the same as when other substances like petroleum products are purified. Small trace amounts remain after processing.
The higher the purity grade, the greater the cost. That’s why it is important to search for a nitrogen gas purity grade that matches your specific application.
Nitrogen is used in a broad range of different industries. As an inert gas, nitrogen gas uses range from food processing and medical testing to the purging of crude oil pipelines. Fortunately, nitrogen is both economical and practical. Often people expect using nitrogen to involve transporting compressed gas cylinders to the site.
In fact, purchasing NiGen’s onsite nitrogen generators to produce nitrogen onsite can make the use of nitrogen extremely convenient and cost-effective. Onsite nitrogen generation also eliminates the need to store portable tanks and schedule tank deliveries.
Nitrogen Purity Grades
Nitrogen can be produced at a variety of purity grades. The fewer contaminants within the nitrogen, the higher the purity level and the greater the cost to produce the nitrogen.
Different names are assigned to nitrogen grades depending on the industry and the nitrogen manufacturer. That is because there is no standardized naming requirement for nitrogen grades. Rather than relying on the name of the grade, it is important to check the nitrogen’s purity specifications.
High Purity Nitrogen Grades
Within the nitrogen industry, the term “high purity” is generally considered to be any nitrogen that is composed of more than 99.9% nitrogen. High purity nitrogen is often called by different grade names depending on the manufacturer.
For marketing reasons, companies often assign names like ultra-high purity or research grade to their high purity nitrogen.
Zero grade is another common term for nitrogen that contains less than 0.5 part per million of total hydrocarbons. High purity nitrogen usually contains no more than 0.5 parts per million of oxygen and one part per million of carbon dioxide and carbon monoxide. Water content is also limited to no more than three parts per million.
Low Purity Nitrogen Grades
Nitrogen that is between 90% and 99.9% pure is low purity, although the names given can be confusing. Low purity nitrogen might be labeled “High Purity” by a supplier, so it is still vital to check the specific levels of contaminants.
Depending on the application, it can be equally important to consider the percentage of specific contaminants like oxygen or moisture in addition to the overall purity level.
Nitrogen Gas Purity Grades by Application
The necessary level of purity and the amount and types of acceptable contaminants depends upon the industry and application. For example, when combustion is a concern, the oxygen levels can be of greatest importance. The moisture content of the nitrogen can become a significant issue when corrosion is a potential problem.
Industrial Grade Nitrogen Specification
Nitrogen is used in a wide range of industrial applications, but most of them require only low purity grade nitrogen. Industrial grade nitrogen generally needs to be within the 95-97% purity level, depending on the application.
The metals industry values nitrogen for a wide variety of purposes. For example, nitrogen is used to sparge molten metal during aluminum degassing and to prevent oxides during aluminum extrusion.
In aluminum degassing, the molten metal is sparged with nitrogen, pushing out hydrogen which can cause gaseous occlusions. Aluminum degassing requires purity of at least 97%.
In aluminum extrusion, the nitrogen with 99.5% or higher purity is appropriate. This prevents the formation of oxides on the metal.
The same purity level or lower is appropriate for nitrogen laser cutting where the nitrogen is used to limit oxidation and to remove dust. Contaminants in the air can cause the laser energy to be diffused, making nitrogen a better option when cleaner laser cuts are desired.
Oil and gas industries rely on the inert properties of nitrogen for safety reasons as the presence of oxygen can result in problems with flammable substances. A pipeline maintenance company, for example, can purchase NiGen’s portable nitrogen generators to test pipelines and other facilities. That could include using nitrogen to check for leaks after repairs, push smart pipeline pigs, or purge pipelines. Portal nitrogen generators can easily be moved to remote pipeline or storage facility locations so the nitrogen can be produced when and where it is needed.
Nitrogen can purge air from storage tanks and pipelines to eliminate flammable oxygen that can be a safety hazard. The low-moisture nitrogen then extends the lifetime of pipelines and containment vessels by eliminating the moisture that speeds the development of rust. Before being put into service, gas turbines can be sealed with a cushion of industrial grade nitrogen. The petroleum industry usually requires nitrogen purity in the 95%-99% range.
Other uses of industrial grade nitrogen include purging air from mines and other enclosed spaces to eliminate the oxygen and other flammable gases to reduce the risk of fires and explosions. If you only need nitrogen periodically, you can contact NiGen for industrial nitrogen generator rentals to meet your nitrogen needs at any time.
Food Grade Nitrogen Specification
Food grade nitrogen requires the 98%-99.5% purity level. Nitrogen is used in numerous ways by the food industry as a cryogenic agent. Purging air with nitrogen extends the life of packaged foods by reducing discoloration and spoilage while helping to preserve flavors. Nitrogen’s applications in the food industry include its use in bottling wines, packaging dry foods like coffee, and in producing shelf-stable foods.
To inhibit the growth of specific types of bacteria in food, the nitrogen can be mixed with small amounts of oxygen or carbon dioxide. Replacing the oxygen with nitrogen helps to protect oils in the food from becoming rancid so that it stays fresher longer. Nitrogen flushing food packaging eliminates air and the contaminants like bacteria the air might contain. Food grade nitrogen generally contains low levels of carbon monoxide and carbon dioxide and limited amounts of moisture.
Medical Grade Nitrogen Gas Specification
Medical grade nitrogen is typically 99% pure. Nitrogen is used in a gas form to fill medical instruments and displace air from medical vessels and equipment.
Liquid nitrogen is used to perform cryosurgery, which is a common way to remove skin lesions and certain types of cancers. Tissue samples, cells, and blood can also be preserved using liquid nitrogen. It quickly freezes without allowing oxidation. High purity nitrogen generators can produce the necessary nitrogen onsite so that it is readily available whenever needed in medical and laboratory facilities.
Pharmaceutical Grade Nitrogen Specification
The pharmaceutical industry utilizes high purity nitrogen in a range of applications. Nitrogen is used for packaging medicine in order to purge the oxygen and other contaminants that can cause medicines to degrade more rapidly. Nitrogen can purge air from equipment and receptacles to ensure contamination doesn’t interfere with testing results or compromise the quality of medicines during their production. Pharmaceutical grade nitrogen has a 97%-99.9995% purity level.