RU2154785C1 - Cryogenic system for liquefaction of air - Google Patents

Abstract

FIELD: cryogenic systems. SUBSTANCE: air is compressed in compressor and after cleaning it from admixtures air is cooled in counter-current heat exchanger and is expanded in throttle valve. Liquid air thus obtained is drained into reservoir. Non-condensed air is discharged to counter-current heat exchanger through gaseous air line via intake device; then air is discharged to expansion reservoir through throttle valve and condenser of Stirling refrigerating machine through throttle valve. Liquefied air is drained to Dewar flask and is fed to reservoir by means of high- pressure pump through check valve. EFFECT: enhanced efficiency; increase of liquefaction coefficient to 100%. 2 cl, 1 dwg

Description

 The invention relates to the field of cryogenic air liquefaction techniques and cryogenic refrigeration machines operating on the reverse Stirling cycle.

 Known technical solutions for the gasification of liquefied gases before distributing them to consumers using high pressure pumps (Questions of deep cooling. / Sat articles edited by prof. MPMalkov /. Ed .: "Foreign Literature", M., 1961 , p. 287-288).

 A device of the Dewar vessel for liquid nitrogen with vacuum-powder insulation is known (Sokolov E.Ya., Brodyansky V.M. Energy fundamentals of heat transformation and cooling processes: Textbook for universities. - 2nd ed., - M.: Energoizdat 1981, p. 202).

It is known that in the range of cryogenic temperatures (60–160 K), the reverse Stirling cycle is the most highly efficient cycle. The efficiency of cryogenic Stirling machines is almost 2 times higher compared to other plants used for gas liquefaction (IP Usyukin Installations, machines and apparatuses of cryogenic technology. M.: Light and food industry, 1982, pp. 185-186.)
A device of the gas refrigerating machine "Philips", operating on the reverse Stirling cycle, designed to liquefy the air (Questions of deep cooling. / Collection of articles edited by prof. MPMalkov. / Publishing house: "Foreign literature", M ., 1961, p. 35).

 However, the currently existing cryogenic Stirling machines have low productivity.

 A device with a high performance Hampson cycle fluidizer is known that includes an air supply line, a compressor, a cleaner, a counter-flow heat exchanger, a throttle valve, a container with liquid air, a non-condensed air supply line connecting the container with liquid air, and a compressor. (RB Scott. The technique of low temperatures. Translation under the editorship of prof. MP Malkov, M .: Publishing House of Foreign Literature, 1962, p. 19). However, the Hampson cycle has a low efficiency and liquefaction coefficient, as a result of which only part of the air compressed by the compressor liquefies, and the remaining part of the gaseous air is again supplied to the compressor, which also reduces the efficiency of the installation as a whole.

 The technical result that can be obtained by carrying out the invention is to increase the efficiency of the liquefaction system and increase the liquefaction coefficient to 100%.

 To achieve this technical result, the cryogenic system for liquefying air according to the Kirillov cycle, which includes an air supply line, a compressor, a purifier, a counterflow heat exchanger, a throttle valve, a tank with liquid air, is equipped with a closed air condensation circuit including a cryogenic Stirling machine with a working fluid helium , a line of gaseous air with a suction device in the gas-containing part of the tank with liquid air, a throttle valve, an expansion tank and a line of liquefied air with Dewar house, a high pressure pump and a check valve connecting the vessel with liquid air cryogenic Stirling machine, with the gaseous air line passes through a counterflow heat exchanger, as in the system may include several parallel cryogenic Stirling machines.

 The introduction into the composition of the cryogenic system for air liquefaction according to the Cyril cycle of a closed air condensation circuit, a cryogenic Stirling machine with a working fluid - helium, a line of gaseous and liquefied air connecting the liquid air tank with a cryogenic Stirling machine, allows to obtain a new property, which consists in the possibility of re-fluidizing the remaining parts of gaseous air after its expansion in the throttle valve and increasing the overall efficiency of the system due to the use of a highly efficient cryogenic Stirling machine with edvaritelnym throttling gaseous air before it.

 The drawing shows a cryogenic system for liquefying air according to the Kirillov cycle.

 Kirillov’s liquefaction cycle includes the following processes: air compression in a compressor, air purification, pre-cooling in a counterflow heat exchanger, throttle expansion followed by condensation of a part of the air (Joule-Thomson effect), throttling of the remaining part of gaseous air, liquefaction in the condenser of a cryogenic machine Stirling and supplying liquid air to a container for liquid air.

 The cryogenic system for air liquefaction in the Kirillov cycle includes an air supply line 1, a compressor 2, an air purifier 3, a counterflow heat exchanger 4, a throttle valve 5, a container with liquid air 6, a closed air condensation circuit, consisting of a cryogenic Stirling machine 7 with a condenser (not shown), the gaseous air line 8 with the intake device 9 in the gas-containing part of the tank 6, a throttle valve 10, an expansion tank 11 and a liquefied air line 12 with a dewar vessel 13, a high pressure pump 14 and a sample tnym valve 15.

 The cryogenic system for liquefying air according to the Kirillov cycle works as follows.

 Air through the supply line 1 enters the compressor 2, where it is compressed to high pressure and enters the purifier 3 for cleaning impurities. Then it is pre-cooled in the counterflow heat exchanger 4 due to heat exchange with cold air and, passing through the throttle valve 5, partially condenses. The liquid air is discharged into the tank 6. The remaining part of the non-condensed cold air through the gaseous air line 8 through the intake device 9 first enters the counterflow heat exchanger 4, where it cools the primary air, and then into the throttle valve 10, passing through which to the expansion tank 11, is cooled and enters the capacitor (not shown) of the cryogenic Stirling machine 7, where it is condensed. The transition of gaseous air into the liquid phase in the condenser of the refrigeration machine 7 creates the necessary pressure difference in line 8. Then the liquefied air through line 12 is discharged into the Dewar vessel 13 and through the check valve 15 is supplied to the container 6 in the form of a liquid.

Claims (2)

 1. Cryogenic system for liquefying air, which includes an air supply line, a compressor, a purifier, a counterflow heat exchanger, a throttle valve, a container with liquid air, characterized in that it is equipped with a closed air condensation circuit, including a cryogenic Stirling machine with a working fluid helium, a line gaseous air with a suction device in the gas-containing part of the tank with liquid air, a throttle valve, an expansion tank, and a liquefied air line with a dewar vessel, a high pressure pump and a twin valve connecting the container with liquid air to the cryogenic Stirling machine, while the line of gaseous air passes through a counterflow heat exchanger.  2. The cryogenic system for liquefying air according to claim 1, characterized in that the system includes several cryogenic Stirling machines in parallel.