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US 5,666,824 AGranted
Cryogenic rectification system with staged feed air condensation
AssigneePraxair Technology, Inc.
InventorDante Patrick Bonaquist
Life of this patent
Estimating the term…
Abstract
A double column cryogenic rectification system for producing lower purity oxygen wherein a minor portion of the feed air is successively condensed in two vertically oriented stages within the lower pressure column before undergoing rectification.
Claims10
A method for producing lower purity oxygen by the cryogenic rectification of feed air in a double column having a higher pressure column and a lower pressure column comprising:
- (A) passing a first portion of the feed air into the higher pressure column and separating the first feed air portion within the higher pressure column by cryogenic rectification into oxygen-enriched and nitrogen-enriched fluids;
- (B) passing oxygen-enriched and nitrogen-enriched fluids from the higher pressure column into the lower pressure column;
- (C) partially condensing a second portion of the feed air by indirect heat exchange with fluid within the lower pressure column to produce a first liquid air portion and a first vapor air portion;
- (D) at least partially condensing the first vapor air portion by indirect heat exchange with fluid within the lower pressure column at a point above the point where step (C) is carried out to produce a second liquid air portion;
- (E) passing the first liquid air portion and the second liquid air portion into the lower pressure column each at a point above the point where step (C) is carried out with the second liquid air portion passed into the lower pressure column above where the first liquid air portion is passed into the lower pressure column;
- (F) separating the fluids passed into the lower pressure column by cryogenic rectification into nitrogen-rich fluid and oxygen-rich fluid;
- and
- (G) recovering oxygen-rich fluid as product lower purity oxygen.
5 more elements
Apparatus for producing lower purity oxygen comprising:
- (A) a double column having a first column and a second column;
- (B) means for passing a first portion of feed air into the first column;
- (C) means for passing fluid from the first column into the second column;
- (D) a first heat exchanger within the second column and means for passing a second portion of feed air into the first heat exchanger;
- (E) a second heat exchanger within the second column at a point above the first heat exchanger, and means for passing vapor from the first heat exchanger into the second heat exchanger;
- (F) means for passing liquid from the first heat exchanger and liquid from the second heat exchanger into the second column each at a point above the first heat exchanger with liquid from the second heat exchanger passed into the second column above where liquid from the first heat exchanger passed into the second column;
- and
- (G) means for recovering product lower purity oxygen from the second column.
5 more elements
A method for producing lower purity oxygen by the cryogenic rectification of feed air in a double column having a higher pressure column and a lower pressure column comprising:
- (A) passing a first portion of the feed air into the higher pressure column and separating the first feed air portion within the higher pressure column by cryogenic rectification into oxygen-enriched and nitrogen-enriched fluids;
- (B) passing oxygen-enriched and nitrogen-enriched fluids from the higher pressure column into the lower pressure column;
- (C) partially condensing a second portion of the feed air by indirect heat exchange with fluid within the lower pressure column to produce a first liquid air portion and a first vapor air portion;
- (D) at least partially condensing the first vapor air portion by indirect heat exchange with fluid within the lower pressure column at a point above the point where step (C) is carried out to produce a second liquid air portion;
- (E) passing the first liquid air portion and the second liquid air portion into the lower pressure column each at a point above the point where step (C) is carried out;
- (F) separating the fluids passed into the lower pressure column by cryogenic rectification into nitrogen-rich fluid and oxygen-rich fluid;
- (G) recovering oxygen-rich fluid as product lower purity oxygen;
- (H) partially condensing a third portion of the feed air by indirect heat exchange with fluid within the lower pressure column to produce a third liquid air portion and a further vapor air portion;
- (I) at least partially condensing the further vapor air portion by indirect heat exchange with fluid within the lower pressure column at a point above the point where step (H) is carried out to produce a further liquid air portion;
- and
- (J) passing the third liquid air portion and the fourth liquid air portion into the lower pressure column each at a point above the point where step (H) is carried out.
8 more elements
Apparatus for producing lower purity oxygen comprising:
- (A) a double column having a first column and a second column;
- (B) means for passing a first portion of feed air into the first column;
- (C) means for passing fluid from the first column into the second column;
- (D) a first heat exchanger within the second column and means for passing a second portion of feed air into the first heat exchanger;
- (E) a second heat exchanger within the second column at a point above the first heat exchanger, and means for passing vapor from the first heat exchanger into the second heat exchanger;
- (F) means for passing liquid from the first heat exchanger and liquid from the second heat exchanger into the second column each at a point above the first heat exchanger;
- (G) means for recovering product lower purity oxygen from the second column;
- and
- (H) a third heat exchanger within the second column, means for passing a third portion of feed air into the third heat exchanger, a fourth heat exchanger within the second column at a point above the third heat exchanger, means for passing vapor from the third heat exchanger into the fourth heat exchanger, and means for passing liquid from the third heat exchanger and from the fourth heat exchanger into the second column each at a point above the third heat exchanger.
6 more elements
Dependencies are inferred from the claim text.