Air separation in a double rectification column
AssigneeThe BOC Group, Inc.
InventorPaul Higginbotham
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Abstract
Air is separated in a double rectification column comprising a higher pressure rectification column, a lower pressure rectification column and a condenser-reboiler placing the higher pressure rectification column in heat exchange relationship with the lower pressure rectification column. At least one stream of air is introduced into the double rectification column, a stream of pressurized liquid comprising oxygen and nitrogen is reduced in pressure by passage through a valve and is partially or totally vaporized in a vaporizer-condenser, a stream of resulting vapor from the partial or total vaporization is compressed in a compressor at cryogenic temperature and is introduced into the double rectification column, and an oxygen produce is withdrawn from the lower pressure rectification column through an outlet.
Claims16
A method of separating air in a double rectification column comprising a higher pressure rectification column, a lower pressure rectification column, and a condenser-reboiler placing the higher pressure rectification column in heat exchange relationship with the lower pressure rectification column, said method comprising:
- introducing at least one stream of air into the double rectification column;
- pressure reducing a liquid stream of pressurised liquid comprising oxygen and nitrogen;
- at least partially vaporizing said liquid stream;
- producing a vapor stream from the at least partial vaporization of the liquid stream;
- compressing said vapor stream at cryogenic temperature;
- indroducing said vapor stream after the compression thereof into the double rectification column;
- withdrawing an oxygen product from the lower pressure rectification column.
An apparatus for separating air, comprising:
- a double rectification column comprising a higher pressure rectification column, a lower pressure rectification column, and a condenser-reboiler placing the higher pressure rectification column in indirect heat exchange relationship with the lower pressure rectification column;
- at least one inlet to the double rectification column for at least one stream of air to be separated;
- a vaporiser-condenser having vaporising passages in communication via pressure reduction means with a source of pressurised liquid comprising oxygen and nitrogen to be partially or totally vaporised;
- a cryogenic compressor having a compressor inlet communicating with an outlet for vaporised pressured liquid from the vaporiser-condenser and a compressor outlet communicating with the double rectification column;
- and
- a product outlet for oxygen product from the lower pressure rectification column.
Dependencies are inferred from the claim text.