Production Of High-Pressure Gaseous Nitrogen

Abstract

An improved process for producing elevated pressure nitrogen including providing an air separation unit with at least two columns. The process includes extracting a first nitrogen stream from the MP column, warming a first portion of the first nitrogen stream in a heat exchanger, thereby producing a product nitrogen stream, and warming a second portion of the nitrogen stream in the heat exchanger, thereby producing warm nitrogen stream. Expanding the warm nitrogen stream in an expander, thereby producing a quantity of work, and a low pressure nitrogen stream and introducing the low pressure nitrogen stream into the LP column. Extracting a second nitrogen stream from the LP column, cooling the second nitrogen stream in condenser, thereby producing a liquid nitrogen stream. Introducing a first portion of the liquid nitrogen stream into the LP column, increasing the pressure of a second portion of the liquid nitrogen stream, thereby producing a pressurized liquid nitrogen stream, and introducing a first portion of the pressurized liquid nitrogen stream into the MP column, and export a second portion of the pressurized liquid nitrogen stream as product.

1 . An improved process for producing elevated pressure nitrogen, comprising;
 providing an air separation unit with at least two columns, an LP column and an MP column,   extracting a first nitrogen stream from said MP column,   warming a first nitrogen portion of said first nitrogen stream in a heat exchanger, thereby producing a product nitrogen stream, and warming a second nitrogen portion of said nitrogen stream in said heat exchanger, thereby producing warm nitrogen stream,   expanding said warm nitrogen stream in an expander, thereby producing a quantity of work, and a low pressure nitrogen stream, and introducing said low pressure nitrogen stream into said LP column,   extracting a second nitrogen stream from said LP column,   cooling said second nitrogen stream in condenser, thereby producing a liquid nitrogen stream,   introducing a first liquid nitrogen portion of said liquid nitrogen stream into said LP column,   increasing the pressure of a second liquid nitrogen portion of said liquid nitrogen stream, thereby producing a pressurized liquid nitrogen stream, and   introducing a first pressurized nitrogen portion of said pressurized liquid nitrogen stream into said MP column, and export a second pressurized nitrogen portion of said pressurized liquid nitrogen stream as product.   
     
     
         2 . The process of  claim 1 , wherein a third nitrogen portion of said first nitrogen stream is introduced into an LP column vaporizer. 
     
     
         3 . The process of  claim 1 , wherein said product nitrogen stream is further compressed in a product compressor, thereby producing a pressurized product nitrogen stream. 
     
     
         4 . The process of  claim 1 , further comprising:
 removing a rich liquid stream from said MP column,   removing a cooling stream from said nitrogen condenser,   indirectly exchanging heat between said rich liquid stream and said cooling stream, thereby producing a subcooled rich liquid stream which is then introduced into said LP column.