Back to results
US 6,546,748 B1Granted
Cryogenic rectification system for producing ultra high purity clean dry air
AssigneePraxair Technology, Inc.
InventorsRichard Martin Kelly, Thomas John Bergman, Jr.
Life of this patent
Estimating the term…
Abstract
A cryogenic rectification system wherein feed air is provided into the lower portion of a cryogenic rectification column, and liquid having a defined oxygen concentration is withdrawn from a defined intermediate level of the column above the feed air introduction level, vaporized and optionally diluted with nitrogen for recovery as ultra high purity clean dry air.
Claims10
A method for producing ultra high purity clean dry air comprising:
- (A) passing feed air at a feed air level into a cryogenic rectification column and producing by cryogenic rectification within the column a nitrogen-rich fluid and an oxygen-enriched fluid;
- (B) withdrawing nitrogen-rich fluid from the upper portion of the column, and withdrawing oxygen-enriched fluid from the lower portion of the column;
- (C) withdrawing liquid having an oxygen concentration within the range of from 10 to 50 mole percent from the column at a withdrawal level which is within the range of from 1 to 25 equilibrium stages above the feed air level;
- and
- (D) vaporizing the withdrawn liquid and recovering the resulting vapor as ultra high purity clean dry air.
2 more elements
Apparatus for producing ultra high purity clean dry air comprising:
- (A) a heat exchanger, a cryogenic rectification column, and means for passing feed air into the cryogenic rectification column at a feed air level;
- (B) means for withdrawing fluid from the upper portion of the cryogenic rectification column, and means for withdrawing fluid from the lower portion of the cryogenic rectification column;
- (C) means for passing liquid withdrawn from the cryogenic rectification column at a level within the range of from 1 to 25 equilibrium stages above the feed air level to the heat exchanger;
- and
- (D) means for recovering ultra high purity clean dry air from the heat exchanger.
2 more elements
Dependencies are inferred from the claim text.