Liquefied gases, refrigeration

Refrigeratiitg Machines, containing non-flammable, non-poisonous, liquefied gas Refrigerating Machines, containing 2857 21 organic, n.o.s. Self-Heating Liquid, inorganic, corrosive, n.o.s. ... 

For the above reasons, gas Is typically economic to develop only if it can be used locally, i.e. if a local demand exists. The exception to this is where a sufficient quantity of gas exists to provide the economy of scale to make transportation of gas or liquefied gas attractive. As a guide, approximately 10 Tcf of recoverable gas would be required to justify building a liquefied natural gas (LNG) plant. Globally there are few such plants, but an example would be the LNG plant in Malaysia which liquefies gas and transports it by refrigerated tanker to Japan. The investment capital required for an LNG plant Is very large typically in the order of 10 billion. 

The liquefied gas must be maintained at or below its boiling point. Refrigeration can be used, but the usual practice is to cool by evaporation. The quantity of liquid evaporated is minimized by insulation. The vapor may be vented to the atmosphere (wasteful), it may be compressed and reliquefied, or it may be used. 

Refrigeration Loss of containment of a liquefied gas under pressure and at atmospheric temperature causes immediate flashing of a large proportion of the gas. This is followed by slower evaporation of the residue. The hazard from a gas under pressure is normally much less in terms of the amount of material stored, but the physical energy released if a confined explosion occurs at high pressure is large. 

A liquefied gas or any mixture of liquefied gases, which is flammable in air and has a boiling point <0°C (measured at 1 bar absolute), when held under refrigeration or cooling at a pressure <1.4 bar absolute. 

Ammonia is shipped as a liquefied gas under its own vapour pressure of 114 psig (7.9 bar) at 21°C. Uses are to be found in refrigeration, fertilizer production, metal industries, the petroleum, chemical and rubber industries, domestic cleaning agents and water purification. Aqueous solutions of ammonia are common alkaline laboratory reagents ca 0.88 solution is the strongest available. Ammonia gas is expelled on warming. 

If the pressure on a liquefied gas is reduced, some of the liquid evaporates, and the rest gets colder. All refrigeration plants, domestic and... 

Recommendations for the design and construction of refrigerated liquefied gas storage tanks... 

Cryogenic Liquid A cryogenic liquid is a refrigerated liquefied gas having a boiling point colder than -130 °F at one atmosphere, absolute. A material that meets this definition is subject to the same requirements tor compressed gases widrout regard to whether it meets the standard definition of a compressed gas. 

Industrial analysis of hydrocarbon gases 25 years ago was limited almost to Orsat-type absorptions and combustion, resulting in crude approximations and inadequate qualitative information. The more precise method of Shepherd (56) was available but too tedious for frequent use. A great aid to the commercial development of hydrocarbon gas processes of separation and synthesis was the development and commercialization of high efficiency analytical gas distillation units by Podbielniak (50). In these the gaseous sample is liquefied by refrigeration, distilled through an efficient vertical packed column, the distillation fractions collected as gas and determined manometrically at constant volume. The operation was performed initially in manually operated units, more recently in substantially automatic assemblies. 

Usually, leaks of liquefied gases are much less serious if such gases are stored refrigerated at low temperatures and pressures than if they are stored at ambient temperatures under pressure. A leak of a volatile liquid held at atmospheric temperature and pressure results in only a relatively slow evaporation of the liquid. Escape of a refrigerated liquefied gas at atmospheric pressure gives some initial flashoff, and then it evaporates at a rate that is relatively slow but faster than the first case, depending on weather conditions. 

Refrigerated liquefied gas means a gas which when packaged is made partially liquid because of its low temperature ... 

Example a b c d e f g Cold or refrigerated solid Solid Warm hot liquid Cold liquid Liquid Hot liquid Hot or warm compressed gas or vapor over hot liquid Compressed liquefied gas MP > f < MP and f... 

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