Argon enhancing method and device

Abstract

An air separation apparatus is provided, including an air separation unit including a low-pressure column, a mixing column, and a pure nitrogen column, wherein the low-pressure column has a first nominal diameter, the pure nitrogen column has a second nominal diameter which is smaller than the first nominal diameter, wherein the mixing column has an open cylindrical shape, with the inner diameter nominally greater than the second nominal diameter, with the pure nitrogen column located within the mixing column interior.

1 - 5 . (canceled) 
     
     
         6 . An air separation apparatus comprising:
 an air separation unit comprising a low-pressure column, a mixing column, and a pure nitrogen column,   wherein the low-pressure column has a first nominal diameter, the pure nitrogen column has a second nominal diameter, which is smaller than the first nominal diameter;   wherein the mixing column has an open cylindrical shape, with an interior having an inner diameter nominally greater than the second nominal diameter, with the pure nitrogen column located within the mixing column interior.   
     
     
         7 . The apparatus of  claim 6 , wherein the mixing column and the pure nitrogen column are in fluidic contact with a distil end of the low-pressure column. 
     
     
         8 . The apparatus of  claim 6 , wherein the mixing column is configured to:
 receive liquid oxygen reflux;   produce rich oxygen waste;   receive waste nitrogen from the low-pressure column; and   return rich liquid to the low-pressure column.   
     
     
         9 . The apparatus of  claim 6 , wherein the pure nitrogen column is configured to:
 receive sub-cooled liquid nitrogen reflux;   produce pure nitrogen;   receive waste nitrogen from the low-pressure column; and   return rich nitrogen liquid to the low-pressure column.   
     
     
         10 . A process for enhanced argon recovery having an air separation unit, the process comprising the steps of:
 providing an air separation unit comprising a low-pressure column, a mixing column, and a pure nitrogen column, wherein the low-pressure column has a first nominal diameter, the pure nitrogen column has a second nominal diameter which is smaller than the first nominal diameter,
 wherein the mixing column has an open cylindrical shape, with an interior having an inner diameter nominally greater than the second nominal diameter, with the pure nitrogen column located within the mixing column interior, 
 wherein the mixing column and the pure nitrogen column are in fluidic contact with a distil end of the low-pressure column; 
   sending a liquid oxygen reflux stream to the mixing column;   withdrawing a rich oxygen waste stream from the mixing column;   sending a first waste nitrogen stream from the low-pressure column to the mixing column;   sending a rich liquid stream from the mixing column to the low-pressure column;   sending a sub-cooled liquid nitrogen reflux stream to the pure nitrogen column;   withdrawing a pure nitrogen stream from the pure nitrogen column;   sending a second waste nitrogen stream from the low-pressure column to the pure nitrogen column;   sending a nitrogen rich liquid stream from the pure nitrogen column to the low-pressure column; and   introducing the rich oxygen waste stream and a third waste nitrogen stream from the low-pressure column to the argon column.