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US 12,742,591 B2Granted
Dual temperature liquid oxygen subcooling in an air separation unit
AssigneeL'Air Liquide, Societe Anonyme pour l'Etude et l'Exploitation des Procedes Georges Claude
InventorsMichael A. Turney, Alain Guillard
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Abstract
A method for production of at least two liquid oxygen product streams from an air separation unit, wherein, the oxygen streams are cooled by heat exchange from at least one gaseous stream comprising predominantly nitrogen from the distillation column, and wherein the product liquid oxygen streams are at different temperatures.
Claims20
A method for production of at least two liquid oxygen product streams from an air separation unit, the method comprising the steps of:
- providing the air separation unit comprised of a main heat exchange zone, a lower-pressure column, a higher-pressure column, an auxiliary heat exchange zone, and a second auxiliary heat exchange zone;
- cooling a compressed air stream in the main heat exchange zone to form a cooled air stream;
- introducing said cooled air stream into the higher-pressure column for rectification in the higher-pressure column;
- withdrawing an oxygen-rich liquid from a bottom section of the higher-pressure column, expanding the oxygen-rich liquid, and then introducing said oxygen-rich liquid into an intermediate section of the lower-pressure column for rectification in the lower-pressure column;
- withdrawing a nitrogen-rich liquid from an upper section of the higher-pressure column, expanding the nitrogen-rich liquid, and then introducing said nitrogen-rich liquid into an upper section of the lower-pressure column for rectification in the lower-pressure column;
- withdrawing a gaseous nitrogen stream from the upper section of the lower-pressure column and warming, sequentially, said gaseous nitrogen stream in the second auxiliary heat exchange zone and then the auxiliary heat exchange zone to form a first warmed nitrogen stream;
- warming the first warmed nitrogen stream in the main heat exchange zone;
- withdrawing a liquid oxygen stream from a bottom section of the lower-pressure column and cooling the liquid oxygen stream in the auxiliary heat exchange zone to form a cooled liquid oxygen stream;
- splitting the cooled liquid oxygen stream into a first oxygen product stream and a second oxygen product stream, wherein the second oxygen product stream is subcooled in the second auxiliary heat exchange zone;
- and
- collecting the first oxygen product stream and the second oxygen product stream, wherein the second oxygen product stream is at a lower temperature as compared to the first oxygen product stream.
8 more elements
An apparatus for production of at least two liquid oxygen product streams, the apparatus comprising:
- a main air compressor;
- a main heat exchange zone;
- a higher-pressure column and a lower-pressure column, wherein the higher-pressure column and the lower-pressure column are thermally linked via a common condenser/reboiler that is disposed in a lower section of the lower-pressure column;
- a first auxiliary heat exchange zone;
- a second auxiliary heat exchange zone;
- a liquid oxygen conduit in fluid communication with the lower section of the lower-pressure column and the first auxiliary heat exchange zone, wherein the first auxiliary heat exchange zone is configured to cool a liquid oxygen stream within the liquid oxygen conduit to a first subcooled temperature, thereby forming a cooled liquid oxygen stream,
- a first oxygen product conduit in fluid communication with the liquid oxygen conduit thereby forming a first oxygen product stream;
- and
- a second oxygen product conduit in fluid communication with the liquid oxygen conduit and the second auxiliary heat exchange zone, thereby forming a second oxygen product stream wherein the second auxiliary heat exchange zone is configured to cool the second oxygen product stream within the second oxygen product conduit to a second subcooled temperature, wherein the second subcooled temperature is lower than the first subcooled temperature.
6 more elements
Dependencies are inferred from the claim text.