Liquefaction of gases
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Liquefaction of gases is physical conversion of a gas into a liquid state (condensation). The liquefaction of gases is a complicated process that uses various compressions and expansions to achieve high pressures and very low temperatures, using, for example, turboexpanders.
Uses
heat of vaporization is released, and evaporated in the evaporator, where the heat of vaporization is absorbed. Ammonia was the first such refrigerant, and is still in widespread use in industrial refrigeration, but it has largely been replaced by compounds derived from petroleum and halogens
in residential and commercial applications.
glycol and numerous other organic compounds as well as phosgene
gas.
Liquefaction of
superfluid (Nobel Prize 1978, Pyotr Kapitsa) and shows characteristic properties such as heat conduction through second sound, zero viscosity and the fountain effect
among others.
The liquefaction of air is used to obtain nitrogen, oxygen, and argon and other atmospheric noble gases by separating the air components by fractional distillation in a cryogenic air separation unit.
History
Liquid air
Linde's process
Air is liquefied by the
Linde process
, in which air is alternately compressed, cooled, and expanded, each expansion results in a considerable reduction in temperature. With the lower temperature the molecules move more slowly and occupy less space, so the air changes phase to become liquid.
Claude's process
Air can also be liquefied by
expansion turbine. The gas is not yet liquid, since that would destroy the turbine. [citation needed] Commercial air liquefication plants bypass this problem by expanding the air at supercritical pressures.[1] Final liquefaction takes place by isenthalpic expansion in a thermal expansion valve
.
See also
- Air Liquide
- Air Products & Chemicals
- Air separation
- The BOC Group
- Chemical engineer
- Compressibility factor
- Fischer–Tropsch process
- Gas separation
- Gas to liquids
- Hampson–Linde cycle
- Industrial gases
- The Linde Group
- Liquefaction
- Liquefaction point
- Louis Paul Cailletet
- Messer Group
- Praxair
- Siemens cycle
- Turboexpander
References
- ^ Greenwood, Harold Cecil (1919). Industrial Gases. D. Van Nostrand. p. 87.