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.
Claims5
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 the 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a crude argon column connected to the lower pressure column to rectify an argon-oxygen containing vapor stream withdrawn from the lower pressure column to thereby, at least in part, produce a crude argon stream and an argon refining column to rectify the crude argon stream and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 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.
Dependencies are inferred from the claim text.