Linde Aktiengesellschaft

Linde Aktiengesellchaft

Gerhard Pompl

J&uuml;rgen Voit

Franz Habicht

A method to obtain a gaseous product by the low temperature fractionation of air includes supplying a first, purified and cooled stream of air to a high-pressure column. At least one liquid stream from the high-pressure column is passed into a low-pressure column. A product stream in the liquid state is drawn off from the low-pressure column and is brought to an elevated pressure. The product stream is then evaporated in an indirect heat exchange with a second purified stream of air. The second stream of air, which is condensed at least partly during the indirect heat exchange, is expanded at least partly in a work-producing manner. The second stream of air subsequently is passed into the low-pressure column. The pressure of the second stream of air at the outlet of the work-expansion is lower than the operating pressure in the sump of the high-pressure column. The work-expansion of the second stream of air is carried out in a single step.

Method and apparatus for obtaining a gaseous product by cryogenic air separation

The process and the apparatus are used to obtain argon using a three-column system for the fractionation of air, which has a high-pressure column ( ), a low-pressure column ( ) and a medium-pressure column ( ). A first charge air stream ( ) is introduced into the high-pressure column ( ), where it is separated into a first oxygen-enriched liquid and a first nitrogen top gas. A first oxygen-enriched fraction ( ) from the high-pressure column ( ) is introduced into the medium-pressure column ( ), where it is separated into a second oxygen-enriched liquid and a second nitrogen top gas. A second oxygen-enriched fraction ( ), from the high-pressure column and/or from the medium-pressure column ( ), is introduced into the low-pressure column ( ), where it is separated into a third oxygen-enriched liquid and a third nitrogen top gas. An argon-containing fraction ( ) from the low-pressure column ( ) is introduced into a crude argon column ( ), where it is separated into a crude argon top fraction and an oxygen-rich liquid. At least a part ( ) of the crude argon top fraction ( ) is passed into a crude argon condenser ( ), where it is at least partially condensed by indirect heat exchange with at least a part ( ) of the second oxygen-enriched liquid from the medium-pressure column ( ). Oxygen-enriched vapour ( ) which is formed in the process is returned to the medium-pressure column ( ). A fraction ( ) from the upper region of the crude argon column ( ) and/or a part of the crude argon top fraction downstream of the crude argon condenser is obtained as crude argon product.

Three-column system for the low-temperature fractionation of air

The process and the apparatus are used to obtain argon using a three-column system for the fractionation of air, which has a high-pressure column ( ), a low-pressure column ( ) and a medium-pressure column ( ). A first charge air stream ( ) is introduced into the high-pressure column ( ), where it is separated into a first oxygen-enriched liquid and a first nitrogen top gas. A first oxygen-enriched fraction ( ) from the high-pressure column ( ) is introduced into the medium-pressure column ( ), where it is separated into a second oxygen-enriched liquid and a second nitrogen top gas. A second oxygen-enriched fraction ( ), from the high-pressure column and/or from the medium-pressure column ( ) is introduced into the low-pressure column ( ), where it is separated into a third oxygen-enriched liquid and a third nitrogen top gas. An argon-containing fraction ( ) from the low-pressure column ( ) is introduced into a crude argon column ( ), where it is separated into a crude argon top fraction and an oxygen-rich liquid. At least a part ( ) of the crude argon top fraction ( ) is passed into a crude argon condenser ( ), where it is at least partially condensed by indirect heat exchange with at least a part ( ) of the second oxygen-enriched liquid from the medium-pressure column ( ). Oxygen-enriched vapor ( ) which is formed in the process is returned to the medium-pressure column ( ). A fraction ( ) from the upper region of the crude argon column ( ) and/or a part of the crude argon top fraction downstream of the crude argon condenser is obtained as crude argon product.

Obtaining argon using a three-column system for the fractionation of air and a crude argon column

The process and the apparatus are used for the low-temperature fractionation of air. Charge air ( ) which has been compressed and has undergone prior purification is introduced into a rectifier system for nitrogen/oxygen separation. This system comprises a pressure column ( ), a low-pressure column ( ) and a condenser/evaporator system ( ) for heating the low-pressure column ( ). The condenser/evaporator system has a first section ( ) which is designed as a falling-film evaporator. A first oxygen-rich liquid ( ) from the low-pressure column ( ) is introduced into the evaporation passages of the falling-film evaporator ( ), where it is partially evaporated. In the process, an oxygen-rich vapor ( ) and a second oxygen-rich liquid ( ) are formed. At least part of the oxygen-rich vapor ( ) is returned to the low-pressure column ( ). The condenser/evaporator system additionally has a second section ( ), which is designed at least in part as a forced circulation evaporator ( ). At least some of the second oxygen-rich liquid ( ) is passed, by means of a delivery device ( ), to the evaporation passages of the second section ( ) of the condenser/evaporator system.

Process and device for the low-temperature fractionation of air

The process and the apparatus serve for the low-temperature fractionation of air. Compressed and prepurified feed air ( ) is introduced into a rectification system for nitrogen-oxygen separation which has a pressure column ( ). At least a part of the compressed and prepurified feed air is fed ( ) to the pressure column ( ). An oxygen-enriched fraction ( ) is taken off from the pressure column ( ) and passed ( ) to a further working step ( ) within the rectification system. The oxygen-enriched fraction ( ) is taken off at least one theoretical or actual plate ( ) above the point at which the compressed and prepurified feed air ( ) is fed to the pressure column. From the bottom of the pressure column ( ) a purge fraction ( ) is removed in the. liquid state, fed in the liquid state to a purification stage ( ), in which N O is removed, and is taken off from the purification stage ( ) as purified purge fraction ( ).

Method and device for cryogenic air separation

Method and device for evaporating liquid oxygen

The process and the device are used for low-temperature separation of air. A first split stream of compressed and purified air is cooled, fed to a main rectifying system and separated there into liquid oxygen and gaseous nitrogen. A liquid product fraction (for example, oxygen and/or nitrogen) is vaporized in indirect heat exchange with a second split stream of compressed and purified air. The second split stream condenses during indirect heat exchange at least partially. At least a portion of the second split stream, downstream from indirect heat exchange with the liquid product fraction, is used as cooling medium for top cooling of a crude argon column downstream from the main rectifying system. The second split stream makes available all or essentially all the cold needed for liquefaction of crude argon. Preferably, at least a portion of the second split stream, vaporized in the indirect heat exchange in the top condenser of the crude argon column, is fed without further pressure increase to the main rectifying system.

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Beilngries, Germany

Gerhard Pompl