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US 5,402,647 AGranted
Cryogenic rectification system for producing elevated pressure nitrogen
AssigneePraxair Technology, Inc.
InventorsDante P. Bonaquist, Mark J. Roberts
Life of this patent
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Abstract
A cryogenic rectification system for producing large quantities of elevated pressure nitrogen employing an additional column operating at a pressure intermediate to that of higher and lower pressure columns, thereby optimizing nitrogen recovery by improving the flexibility of refrigeration production.
Claims17
A cryogenic rectification method for producing elevated pressure nitrogen gas comprising:
- (A) passing feed comprising nitrogen and oxygen into a first column operating at a high pressure, and separating the feed by cryogenic rectification within the first column into high pressure nitrogen vapor and first oxygen-enriched liquid;
- (B) passing first oxygen-enriched liquid into a second column operating at an intermediate pressure, and separating the first oxygen-enriched liquid by cryogenic rectification within the second column into nitrogen-enriched vapor and second oxygen-enriched liquid;
- (C) passing nitrogen-enriched vapor into the lower portion of a third column operating at a low pressure, and separating the nitrogen-enriched vapor by cryogenic rectification within the third column into nitrogen-containing fluid and oxygen-containing fluid;
- (D) recovering at least some of the high pressure nitrogen vapor as elevated pressure nitrogen gas product;
- and
- (E) passing the nitrogen-containing fluid and the oxygen-containing fluid into a top condenser, condensing the nitrogen-containing fluid by indirect heat exchange with the oxygen-containing fluid within the top condenser, and passing some of the resulting nitrogen-containing liquid into the third column.
3 more elements
A cryogenic rectification apparatus for producing elevated pressure nitrogen gas comprising:
- (A) a first column, and means for passing feed into the first column;
- (B) a second column, and means for passing liquid from the lower portion of the first column into the second column;
- (C) a third column, and means for passing vapor from the upper portion of the second column into the lower portion of the third column;
- (D) means for recovering elevated pressure nitrogen gas taken from the upper portion of the first column;
- and
- (E) a top condenser, means for passing fluid from the upper portion of the third column into the top condenser, means for passing fluid from the lower portion of the third column into the top condenser, and means for passing fluid from the top condenser into the third column.
3 more elements
Dependencies are inferred from the claim text.