Atmospheric Gases :: Nitrogen

Nitrogen, or N₂, is a diatomic gas which comprises 78 percent of the earth's atmosphere. In addition to air, nitrogen is found in the protein matter of all life forms, in some natural gas-hydrocarbon deposits, and in many organic and inorganic compounds.

Colorless, odorless, tasteless, and nontoxic, nitrogen exists as a non-flammable gas at atmospheric temperatures and pressures. A specific gravity of .9669 makes nitrogen slightly lighter than air. When cooled to its boiling point of -320°F, nitrogen becomes a colorless liquid which can, in turn, be compressed into a colorless, crystalline solid. It is only slightly soluble in water and most other liquids, and is a poor conductor of heat and electricity.

Most uses of gaseous nitrogen depend on its inert characteristics. At high temperatures and pressures, however, it will combine with some reactive metals (such as lithium and magnesium) to form nitrides, as well as with some gaseous elements such as hydrogen and oxygen.
 

• Chemical Processing to inert vessels and oxygen-sensitive chemicals, creating an oxygen-deficient environment that reduces safety hazards; to propel liquids through pipelines; and to manufacture ammonia.
   
• Food to extend shelf-life in packaged foods by preventing spoilage from oxidation, mold growth, moisture migration and insect infestation; to rapidly freeze; and to refrigerate perishables during transport.
   
• Petroleum Recovery and Refining to improve recovery and maintain pressure in oil and gas reservoirs; to blanket storage tanks and product loading/unloading; to purge pipelines; and to strip volatile organic compounds (VOCs) from waste streams or to cool vent streams. Controlling VOC emissions helps refiners comply with U.S. Clean Air Act requirements.
    
• Metal Production and Fabrication to protect metals such as steel, copper and aluminum during annealing, carburizing and sintering operations in high temperature furnaces; to cool extrusion dies; and to shrink fit metal parts; utilized as a purge gas with stainless steel tube welding. Also used to support plasma cutting.
   
• Electronics to prevent oxidation in the manufacture of semiconductors and printed circuits; and to enhance solvent recovery systems by eliminating the use of chlorofluorocarbons for cleanup.
   
• Glass Manufacturing to cool furnace electrodes and prevent oxidation during manufacturing; and to lower air temperatures for optimum cooling rates.
   
• Research and Health Services to freeze and preserve blood, tissue, semen and other biological specimens; to freeze and destroy diseased tissue in cryosurgery and dermatology; and to pre-cool or insulate Magnetic Resonance Imaging (MRI), conserving the more costly helium.
   
• Construction to suppress the pour temperature of concrete mixtures, inhibiting the formation of cracks; and to stabilize the ground as in the restoration of the Leaning Tower of Pisa.
   
• Recycling.  Nitrogen's low boiling point and non-toxic properties make it an economical choice for recycling tires through cryopulverization. In this process, liquid nitrogen serves as a freezing agent and embrittles shredded tire scrap so that it can be easily ground into crumb rubber. The resulting product finds use in roofing materials, sealants, oil well linings, recreational surfaces and asphalt paving.
  
  A similar process is used to grind and sort polyvinyl chloride from post-consumer scrap in mixed waste loads, as well as to grind and process dried fruits, delicate herbs and spices.

• Bulk liquid delivery in tank trucks
• Bulk gas delivery in high pressure tube trailer trucks
• Portable Liquid Cylinders
• Portable insulated containers called dewars
• High pressure cylinders