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.
Liquefaction processes are used for scientific, industrial and commercial purposes. Many gases can be put into a liquid state at normal atmospheric pressure by simple cooling; a few, such as carbon dioxide, require pressurization as well. Liquefaction is used for analyzing the fundamental properties of gas molecules (intermolecular forces), or for the storage of gases, for example: LPG, and in refrigeration and air conditioning. There the gas is liquefied in the condenser, where the 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Ammonia was the first such refrigerant, and is still in widespread use in industrial refrigeration, but it has largely been replaced by compounds derived from petroleum and halogens in residential and commercial applications.
Liquid oxygen is provided to hospitals for conversion to gas for patients with breathing problems, and liquid nitrogen is used in the medical field for cryosurgery, by inseminators to freeze semen, and by field and lab scientists to preserve samples. Liquefied chlorine is transported for eventual solution in water, after which it is used for water purification, sanitation of industrial waste, sewage and swimming pools, bleaching of pulp and textiles and manufacture of carbon tetrachloride, glycol and numerous other organic compounds as well as phosgene gas.
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 processedit
Air can also be liquefied by Claude's process in which the gas is allowed to expand isentropically twice in two chambers. While expanding, the gas has to do work as it is led through an 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.
^Greenwood, Harold Cecil (1919). Industrial Gases. D. Van Nostrand. p. 87.
External linksedit
Liquefaction of Gases
History of Liquefying Hydrogen - NASA
April 27, 2024
liquefaction, gases, this, article, includes, list, references, related, reading, external, links, sources, remain, unclear, because, lacks, inline, citations, please, help, improve, this, article, introducing, more, precise, citations, april, 2013, learn, whe. This article includes a list of references related reading or external links but its sources remain unclear because it lacks inline citations Please help improve this article by introducing more precise citations April 2013 Learn how and when to remove this template message 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 Liquid nitrogen Contents 1 Uses 2 History 3 Liquid air 3 1 Linde s process 3 2 Claude s process 4 See also 5 References 6 External linksUses editLiquefaction processes are used for scientific industrial and commercial purposes Many gases can be put into a liquid state at normal atmospheric pressure by simple cooling a few such as carbon dioxide require pressurization as well Liquefaction is used for analyzing the fundamental properties of gas molecules intermolecular forces or for the storage of gases for example LPG and in refrigeration and air conditioning There the gas is liquefied in the condenser where the 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 Liquid oxygen is provided to hospitals for conversion to gas for patients with breathing problems and liquid nitrogen is used in the medical field for cryosurgery by inseminators to freeze semen and by field and lab scientists to preserve samples Liquefied chlorine is transported for eventual solution in water after which it is used for water purification sanitation of industrial waste sewage and swimming pools bleaching of pulp and textiles and manufacture of carbon tetrachloride glycol and numerous other organic compounds as well as phosgene gas Liquefaction of helium 4He with the precooled Hampson Linde cycle led to a Nobel Prize for Heike Kamerlingh Onnes in 1913 At ambient pressure the boiling point of liquefied helium is 4 22 K 268 93 C Below 2 17 K liquid 4He becomes a 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 editFurther information Timeline of low temperature technologyLiquid air editMain article Liquid air Linde s process edit 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 edit Air can also be liquefied by Claude s process in which the gas is allowed to expand isentropically twice in two chambers While expanding the gas has to do work as it is led through an 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 editAir Liquide Air Products amp 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 TurboexpanderReferences edit Greenwood Harold Cecil 1919 Industrial Gases D Van Nostrand p 87 External links editLiquefaction of Gases History of Liquefying Hydrogen NASA Retrieved from https en wikipedia org w index php title Liquefaction of gases amp oldid 1215986095, wikipedia, wiki, book, books, library,
