Discover

'Liquid nitrogen' (liquid density at the triple point is 0.807 g/mL) is the liquid produced industrially in large quantities by fractional distillation of liquid air and is often referred to by the abbreviation, 'LN₂'. It is pure nitrogen, in a liquid state.
Liquid nitrogen is a cryogenic fluid which is potentially capable of causing instant frostbite on contact with living tissue. When appropriately insulated from ambient heat, liquid nitrogen can be stored and transported without significant evaporative losses.

Contents

Applications

Safety

See also

References

Applications

Liquid nitrogen is a compact and readily transported source of nitrogen gas without pressurization. Apart from this, the main applications involve liquid nitrogen as a refrigerant.
Further, its ability to maintain temperatures far below the freezing point of water (it boils at 77 K, which equals −196 °C or −320 °F) makes it extremely useful in a wide range of applications as an open-cycle refrigerant, including:

★ the immersion freezing and transportation of food products

★ the cryopreservation of blood, reproductive cells (sperm and egg), and other biological samples and materials

★ the cryonic preservation of humans and pets in the hope of future reanimation.

★ in the study of cryogenics

★ for demonstrations in science education

★ as a coolant for highly sensitive sensors and low-noise amplifiers

★ in dermatology for removing unsightly or potentially malignant skin lesions such as warts and actinic keratosis

★ as a cooling supplement for overclocking a central processing unit, a graphics processing unit, or another type of computer hardware

★ as a cooling medium during machining of high strength materials.

★ as the working fluid in a binary engine

★ as a means of final disposition of the dead, known as promession.

★ as a method of freezing water pipes in order to work on them in situations where a tap is not available to block water flow to the work area.

Safety

Since the liquid to gas expansion ratio of this substance is 1:694,^[1] a tremendous amount of force can be generated when liquid nitrogen boils off for whatever reasons. In a well known accident in 2006 at Texas A&M University, the pressure-relief devices of a tank of liquid nitrogen were sealed with brass plugs. As a result, the tank failed catastrophically, and exploded. The force of the explosion was sufficient to propel the tank through the floor/ceiling immediately above it.^[2]

See also

★ Computer cooling

★ Liquid nitrogen economy

References

1. Information Specific to Liquid Nitrogen
2. Investigative Report on Chemistry 301A Cylinder Explosion Brent S. Mattox