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US 6,499,312 B1Granted
Cryogenic rectification system for producing high purity nitrogen
AssigneePraxair Technology, Inc.
InventorsThomas John Bergman, Jr., Shanda Gardner Fry, Jeremy Michael Cabral
Life of this patent
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Abstract
A system for producing high and ultra high purity nitrogen comprising a first column for the production of nitrogen and a second column having a top condenser wherein boil off from the second column top condenser is turboexpanded to generate refrigeration for the system.
Claims10
A method for producing high purity nitrogen comprising:
- (A) cleaning feed air in a purification system, cooling cleaned feed air, passing cooled feed air into a first column having a top condenser, and producing by cryogenic rectification within the first column first high purity nitrogen fluid and first oxygen-enriched fluid;
- (B) passing first oxygen-enriched fluid into the first column top condenser, passing a portion of the first oxygen-enriched fluid from the first column top condenser into a second column having a top condenser, passing a portion of the first oxygen-enriched fluid from the first column top condenser to the second column top condenser, and producing by cryogenic rectification within the second column second high purity nitrogen fluid and second oxygen-enriched fluid;
- (C) warming second oxygen-enriched fluid to produce oxygen-enriched vapor, and turboexpanding the oxygen-enriched vapor to generate refrigeration;
- (D) employing refrigeration from the oxygen-enriched vapor to cool the feed air and using the oxygen-enriched vapor to clean the purification system;
- and
- (E) recovering a portion of the first high purity nitrogen fluid as product high purity nitrogen.
3 more elements
Apparatus for producing high purity nitrogen comprising:
- (A) a purification system, a main heat exchanger, a first column having a top condenser, and means for passing feed air to the purification system, from the purification system to the main heat exchanger and from the main heat exchanger to the first column;
- (B) a second column having a top condenser, means for passing fluid from the lower portion of the first column to the first column top condenser, means for passing fluid from the first column top condenser into the second column, and means for passing fluid from the first column top condenser to the second column top condenser;
- (C) means for passing fluid from the lower portion of the second column into the second column top condenser;
- (D) a turboexpander, means for passing fluid from the second column top condenser to the turboexpander, and means for passing fluid from the turboexpander to the main heat exchanger and from the main heat exchanger to the purification system;
- and
- (E) means for recovering high purity nitrogen from the upper portion of the first column.
3 more elements
Dependencies are inferred from the claim text.