Air Separating Device by Means of Cryogenic Distillation

Abstract

The invention relates to an air separating device by means of cryogenic distillation for producing nitrogen, comprising an exchange line ( 3 ), a simple distillation column ( 7 ) containing plates and/or structured packings, a supply line for delivery of compressed purified air ( 1 ) to the exchange line, a supply line for delivery of the compressed purified and cooled air from the exchange line to the distillation column, a line for withdrawal of a liquid ( 11 ) enriched in oxygen from the distillation column for delivery to the exchange line, said exchange line having two sections, a rectifying section ( 3 B) and a heat exchange section ( 3 A), the rectifying section being connected to the column and the line for the enriched liquid and the heat exchange section is connected to the air supply line and the rectifying section.

1 - 9 . (canceled) 
     
     
         10 : An apparatus for separating air by cryogenic distillation for producing nitrogen comprising:
 a) an exchange line;   b) a simple distillation column containing plates and/or structured packings;   c) a line for sending compressed and purified air to the exchange line;   d) a line for sending compressed, purified and cooled air from the exchange line to the distillation column; and   e) a line for withdrawing an oxygen-enriched liquid from the column and for sending it to the exchange line,   
       wherein the exchange line comprises two sections, a deflegmation section and a heat exchange section; the deflegmation section is connected to the column and to the oxygen-enriched liquid line and the heat exchange section is connected to the air supply line and to the deflegmation section. 
     
     
         11 : The apparatus of  claim 10 , in which the exchange line is positioned above the distillation column. 
     
     
         12 : The apparatus of  claim 10 , in which the deflegmation section is fixed to the top of the column. 
     
     
         13 : The apparatus of  claim 10 , comprising means for injection feeding and/or for expanding air or vaporized enriched liquid. 
     
     
         14 : The apparatus of  claim 10 , in which the line for sending compressed, purified, and cooled air from the exchange line to the distillation column is connected to the cold end of the heat exchange section. 
     
     
         15 : The apparatus of  claim 10 , comprising means for redistributing the passages between the heat exchange section and the deflegmation section. 
     
     
         16 : The apparatus of  claim 10 , in which the exchange line is made from copper or aluminum and/or the distillation column is made from stainless steel. 
     
     
         17 : The apparatus of  claim 10 , in which the exchange line and the distillation column are made from aluminum. 
     
     
         18 : A method for separating air by cryogenic distillation for producing nitrogen in an apparatus comprising an exchange line and a simple distillation column containing plates and/or structured packings, in which compressed and purified air is sent to the exchange line, compressed, purified and cooled air is sent from the exchange line to the distillation column, a stream of oxygen-enriched liquid is withdrawn from the column and sent to the exchange line, wherein the exchange line comprises two sections, a deflegmation section and a heat exchange section; the deflegmation section is connected to the column and to the oxygen-enriched liquid line and the heat exchange section is connected to the air supply line and to the deflegmation section, and in that the oxygen-enriched liquid is vaporized completely in the heat exchange section to produce an oxygen-enriched gas.