Main Exchange Line And Cryogenic Distillation Air Separation Unit Incorporating Such An Exchange Line

Abstract

A unit for separating air using cryogenic distillation is provided.

1 - 15 . (canceled) 
   
   
       16 . An exchange line designed to be incorporated into an air separation unit, comprising:
 at least two exchange assemblies, consisting of a first and of a second assembly,   the assemblies being connected in parallel, each assembly comprising:
 at least two exchange bodies, connected in series with one another, 
 means for sending a first flow that is to be cooled to the first assembly, so that the first flow is cooled down in each exchange body of the first assembly, 
 means for sending a second flow that is to be cooled to the second assembly, so that the second flow is cooled down in each exchange body of the second assembly, 
 means for sending a first fluid that is to be heated to the first assembly, so that the first fluid is heated up in each exchange body of the first assembly, and 
 means for sending a second fluid that is to be heated to a second assembly, so that the second fluid is heated up in each exchange body of the second assembly, 
   wherein:
 there is no means that allows some of the first flow to cool down in the second assembly, 
 there is no means that allows some of the second flow to cool down in the first assembly, 
 there is no means that allows some of the first fluid to heat up in the second assembly, and 
 there is no means that allows some of the second fluid to heat up in the first assembly. 
   
   
   
       17 . The exchange line of  claim 16 , wherein each assembly comprises at least three exchange bodies. 
   
   
       18 . The exchange line of  claim 16 , further comprising means for separating a flow that is to be cooled downstream of the two assemblies to form the first and second flows so that the first and second flows that are to be cooled pass in series through each exchange body of their respective assembly. 
   
   
       19 . The exchange line of  claim 16 , comprising two exchange assemblies. 
   
   
       20 . The exchange line of  claim 16 , in which the bodies of one assembly are aligned in the direction of their length. 
   
   
       21 . The exchange line of  claim 16 , wherein the bodies of one assembly are arranged with their length parallel to that of the adjacent bodies. 
   
   
       22 . The exchange line of  claim 16 , wherein the bodies of one assembly are arranged with their length parallel to that of the adjacent bodies and in a staggered configuration. 
   
   
       23 . The exchange line of  claim 16 , wherein each exchange body is a stack of rectangular plates. 
   
   
       24 . The exchange line of  claim 23 , wherein the rectangular plates have rounded corners. 
   
   
       25 . The exchange line of  claim 16 , wherein each exchange body is a stack of irregular hexagonal plates, connecting elements being positioned on each side of each body to connect it to the adjacent body. 
   
   
       26 . The exchange line of  claim 16 , wherein at least one of the exchange bodies is a standardized exchanger. 
   
   
       27 . The exchange line of  claim 26 , wherein at least two of the exchange bodies are of the same model. 
   
   
       28 . An air separation unit comprising:
 a distillation column having a top-end condenser,   an exchange line as claimed in  claim 16 ,   means for sending compressed and purified air to each of the exchange assemblies,   means for withdrawing nitrogen gas from the column,   means for sending the nitrogen gas to a first exchange assembly,   means for sending the column bottom liquid to the condenser,   means for drawing vaporized liquid from the condenser, and   means for sending the vaporized liquid to the second assembly.   
   
   
       29 . The unit of  claim 28 , further comprising means for regulating the amount of air sent to the exchange assemblies. 
   
   
       30 . The unit of  claim 28 , in which at least two exchange bodies of one and the same assembly are placed one above the other, 
   
   
       31 . The unit of  claim 30 , wherein at least two exchange bodies of one and the same assembly are all one above the other. 
   
   
       32 . A method of cooling air in an exchange line, the exchange line comprising:
 at least two exchange assemblies, the assemblies being connected in parallel, each assembly comprising at least two exchange bodies, connected in series with one another,   means for sending a first flow of air that is to be cooled to the first assembly, so that the first flow is cooled down in each exchange body of the first assembly,   means for sending a second flow of air that is to be cooled to the second assembly, so that the second flow is cooled down in each exchange body of the second assembly,   means for sending a first fluid that is to be heated to a first of the exchange assemblies, so that the first fluid is heated up in each exchange body of the first assembly, and   means for sending a second fluid that is to be heated to a second of the exchange assemblies, so that the first fluid is heated up in each exchange body of the second assembly,   the method comprising:
 sending all of the first flow only to the first assembly, 
 sending all of the second flow only to the second assembly, 
 sending all of the first fluid only to the first assembly, and 
 sending all of the second fluid only to the second assembly. 
   
   
   
       33 . The method of  claim 32 , wherein the first and second flows enter their respective assemblies at different pressures and/or different temperatures. 
   
   
       34 . The method of  claim 32 , wherein the first and second flows are combined downstream of the first and second assemblies.