Method For Cooling A Cryogenic Exchange Line

Abstract

The invention relates to a method for the cryogenic separation, the cooling or the liquefaction of a fluid using an exchange line, that comprises extracting from said exchange line at least one dual phase fluid ( 11 ), separating said dual phase fluid into at least one vapour fraction ( 4 ) and one liquid fraction ( 5 ) in a phase separator ( 40 ), expanding at least one portion of the liquid fraction ( 5 ) using a first expansion means ( 60, 90 ), reinjecting, reheating and at least partially vaporising said expanded liquid fraction in the exchange line, the first expansion means being a valve, wherein during the cooling of said exchange line, at least a fraction of the fluid extracted from the exchange line ( 2, 4 or 5 ) and/or from the phase separator ( 40 ) is expanded in second expansion means ( 61, 71, 81, 91 ) parallel to the first expansion means ( 6 ), while during a normal operation, the second expansion means is essentially closed.

1 - 9 . (canceled) 
     
     
         10 : A process for the cryogenic separation, refrigeration or liquefaction of a fluid by means of a heat exchange line comprising:
 extracting at least one two-phase fluid from said heat exchange line;   separating said two-phase fluid into at least a vapor fraction and a liquid fraction in a phase separator;   expanding at least one portion of said liquid fraction by means of a first expansion means; and   re-injecting, warming and at least partially vaporizing said expanded liquid fraction in the heat exchange line,   
       wherein:
 said first expansion means is a valve; 
 as said heat exchange line is being cooled down, at least one fraction of the fluid extracted from the heat exchange line and/or from the phase separator is expanded in a second expansion means in parallel with the first expansion means; and 
 in normal operation, said second expansion means is essentially closed. 
 
     
     
         11 : The process of  claim 10 , wherein said second expansion means is a valve. 
     
     
         12 : The process as of  claim 10 , in which said first and said second expansion means are installed in parallel. 
     
     
         13 : The process of  claim 10 , in which vapor is sent from the phase separator into a third expansion means and, as said heat exchange line is being cooled down, at least one fraction of the vapor is expanded in a second expansion means in parallel with the third expansion means. 
     
     
         14 : The process of  claim 13 , wherein vapor coming from the third expansion means is sent into the liquid coming from the phase separator. 
     
     
         15 : The process of  claim 10 , wherein the HP of the second expansion means is equal to three times the HP of the first expansion means. 
     
     
         16 : The process of  claim 10 , wherein the HP of the second expansion means is equal to five times the HP of the first expansion means. 
     
     
         17 : The process of  claim 14 , in which the HP of the second expansion means is equal to three times the HP of the third expansion means. 
     
     
         18 : The process of  claim 14 , in which the HP of the second expansion means is equal to 5 times the HP of the third expansion means. 
     
     
         19 : The process of  claim 10 , in which, during the cooling-down, the second expansion means is controlled manually or the pressure of the feed gas is regulated. 
     
     
         20 : The process of  claim 10 , in which the cryogenic separation is a process selected from the group consisting of the separation of hydrocarbons, the production of hydrogen, the production of CO 2 , a process for eliminating nitrogen from a heavier fraction, a process for eliminating argon from a heavier fraction, and the liquefaction is a liquefaction of natural gas. 
     
     
         21 : The process of  claim 20 , wherein said hydrogen has a purity of 90 to 98%. 
     
     
         22 : The process of  claim 20 , wherein said CO 2  has a purity of greater than 95%. 
     
     
         23 : The process of  claim 22 , wherein said CO 2  has a purity of greater than 98%.