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US 2012/0125045 A1Published application
Air separation method and apparatus
AssigneePraxair Technology, Inc.
InventorHenry Edward Howard
Life of this patent
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Abstract
A method and apparatus for separating air in which an argon refining column of a distillation column system is reboiled with a liquid air stream. The argon refining column further refines crude argon produced by a crude argon column connected to a lower pressure column of the distillation column system. At least one intermediate reflux stream is formed, at least indirectly, from at least part of the liquid air stream, and is introduced into the lower pressure column at a level thereof above where a crude liquid oxygen column bottoms of a higher pressure column of such system is further refined to increase a liquid to vapor ratio below said level and therefore, argon recovery from the argon refining column.
Claims14
A method of separating air comprising:
- compressing and purifying the air such that a first compressed air stream and a second compressed air stream are produced, the second compressed air stream having a higher pressure than the first compressed air stream;
- cooling at least part of the first compressed air stream and condensing the second compressed air stream through indirect heat exchange with return streams produced by a distillation column system to form a liquid air stream;
- producing a refrigerant stream and imparting refrigeration with the use of the refrigeration stream into the distillation column system;
- introducing the at least part of the first compressed air stream into higher pressure column of a distillation column system, the distillation column system also having a lower pressure column operatively associated with the higher pressure column in a heat transfer relationship, a crude argon column connected to the lower pressure column to rectify an argon-oxygen containing vapor stream withdrawn from the lower pressure column to thereby, at least in part, produce a crude argon stream and an argon refining column to rectify the crude argon stream and thereby form an argon product stream from an argon-rich liquid column bottoms produced in the argon refining column;
- reboiling the argon refining column with the at least a portion of liquid air stream, thereby subcooling the liquid air stream;
- and
- introducing at least one intermediate reflux stream, formed directly or indirectly from at least part of the liquid air stream after having been subcooled, into the lower pressure column at a level thereof above where all or any part of a crude liquid oxygen stream composed of a crude liquid oxygen column bottoms of the higher pressure column is introduced for further refinement.
4 more elements
An apparatus for separating air comprising:
- a main air compressor for compressing the air;
- a purification system connected to the main air compressor for purifying the air and thereby producing a compressed and purified air stream;
- a booster compressor in flow communication with the purification unit such that a first compressed air stream is produced from at least part of the compressed and purified air stream and a second compressed air stream is produced by compressing another part of the compressed and purified air stream in the booster compressor to a higher pressure than the first compressed air stream;
- a main heat exchanger configured to cool at least part of the first compressed air stream and to condense the second compressed air stream and form a liquid air stream through indirect heat exchange with return streams produced by a distillation column system;
- means for imparting refrigeration into the distillation column system;
- the distillation column system having a higher pressure column in flow communication with the main heat exchanger so as to receive the at least part of the first compressed air stream, a lower pressure column operatively associated with the higher pressure column in a heat transfer relationship, a crude argon column connected to the lower pressure column to rectify an argon-oxygen containing vapor stream withdrawn from the lower pressure column and thereby, at least in part, produce a crude argon stream and an argon refining column to rectify the crude argon stream and thereby forming an argon product stream from an argon-rich liquid column bottoms produced in the argon refining column;
- the argon refining column having a bottom reboiler in flow communication with the main heat exchanger to receive the liquid air stream, thereby subcooling the liquid air stream and reboiling the argon refining column;
- and
- means for forming at least one intermediate reflux stream, directly or indirectly, from at least part from the liquid air stream after having been subcooled;
- and
- the intermediate reflux forming means connected to the lower pressure column at a level thereof above where all or any part of a crude liquid oxygen stream composed of a crude liquid oxygen column bottoms of the higher pressure column is introduced for further refinement.
8 more elements
Dependencies are inferred from the claim text.