Air separation unit

Abstract

An air separation unit may include: a main heat exchanger 1 , a first rectification column 2 , a nitrogen condenser 3 , a second rectification column 4 , a third rectification column 5 , a crude argon condenser 6 , a high-purity oxygen rectification column 8 , and a high-purity oxygen reboiler 9 . The air separation unit uses a portion of the feed air that has passed through the main heat exchanger 1 as a heat source in the high-purity oxygen reboiler 9.

1 . An air separation unit comprising:
 a main heat exchanger configured to subject feed air to heat exchange;   a first rectification column to which feed air that has passed through the main heat exchanger is introduced, said first rectification column comprising a first bottom portion in which an oxygen-rich liquid is stored, a first rectification portion for rectifying the feed air, and a first column top portion which is disposed at an upper portion of the first rectification portion and stores a first vaporized gas;   a nitrogen condenser, which is disposed above the first column top portion, configured to condense the first vaporized gas in the first column top portion;   a second rectification column comprising a second rectification portion and a second column top portion from which low-pressure nitrogen gas is drawn;   a third rectification column for rectifying argon, said third rectification column comprising a third bottom portion to which is introduced a crude argon feed gas drawn from an intermediate portion of the second rectification portion of the second rectification column, a third rectification portion for rectifying the crude argon feed gas, and a third column top portion in which argon is stored;   a crude argon condenser, which is disposed above the third column top portion, configured to condense the argon in the third column top portion;   a high-purity oxygen rectification column for rectifying high-purity oxygen, said high-purity oxygen rectification column comprising an oxygen column bottom portion having a high-purity oxygen reboiler disposed in a lower region thereof, an upper portion of an oxygen rectification portion to which is introduced an oxygen-rich liquid drawn from an intermediate portion of the third rectification portion of the third rectification column, and an oxygen column top portion from which an oxygen vaporized gas is drawn to be returned to the intermediate portion of the third rectification portion of the third rectification column; and   a feed air introduction line configured to cause the feed air to pass through the main heat exchanger, and introduce the feed air into the first bottom portion of the first rectification column or into a lower region of the first rectification portion, wherein   a portion of the feed air is used as a heat source in the high-purity oxygen reboiler.   
     
     
         2 . The air separation unit according to  claim 1 , further comprising an upper rectification portion disposed above the crude argon condenser, wherein a portion of an oxygen-rich liquid introduced from the first bottom portion of the first rectification column is introduced into an upper portion of the upper rectification portion and oxygen in the oxygen-rich liquid is rectified. 
     
     
         3 . The air separation unit according to  claim 1 , further comprising a first heat source introduction line which branches from the feed air introduction line, is used for a heat source in the high-purity oxygen reboiler, and leads into a rectification portion of the second rectification column, wherein the feed air which is used as a heat source in the high-purity oxygen reboiler is introduced into an intermediate portion of the second rectification portion of the second rectification column. 
     
     
         4 . The air separation unit according to  claim 2 , further comprising a second heat source introduction line which branches from the feed air introduction line, is used for a heat source in the high-purity oxygen reboiler, and leads into an upper region of the upper rectification portion, wherein the feed air which is used as a heat source in the high-purity oxygen reboiler is introduced into the upper rectification portion. 
     
     
         5 . A method for producing argon and ultra-high-purity oxygen, the method comprising the steps of:
 providing the air separation unit of  claim 1 ; and   using a portion of the feed air, which has passed through the main heat exchanger, as a heat source in the high-purity oxygen reboiler.