Method for liquefying a flow rich in hydrocarbons

Abstract

A process is described for liquefaction of a hydrocarbon-rich stream, especially a natural gas stream, at least indirect heat exchange taking place between the hydrocarbon-rich stream to be liquefied and the refrigerant mixture of at least one refrigerant mixture circuit, and the refrigerant mixture being separated after completed supercooling into a gaseous fraction and a liquid fraction and these fractions being recombined before and/or during the reheating of the refrigerant mixture. According to the invention, a gas fraction ( 9 ) that is identical or similar in composition is added at least from time to time to the gas fraction ( 4 ) that has been obtained in the separation (D). In doing so, the addition of the gas fraction ( 9 ) that is identical or similar in composition takes place when a minimum amount of the gas fraction ( 4 ) obtained in the separation (D) of the refrigerant mixture is not reached.

1 . Process for liquefaction of a hydrocarbon-rich stream, especially a natural gas stream, at least indirect heat exchange taking place between the hydrocarbon-rich stream to be liquefied and the refrigerant mixture of at least one refrigerant mixture circuit, and the refrigerant mixture being separated after completed supercooling into a gaseous fraction and a liquid fraction and these fractions being recombined before and/or during the reheating of the refrigerant mixture, characterized in that a gas fraction ( 9 ) that is identical or similar in composition is added at least from time to time to the gas fraction ( 4 ) that has been obtained in the separation (D).  
     
     
         2 . Process for liquefaction of a hydrocarbon-rich stream according to  claim 1 , wherein the addition of the gas fraction ( 9 ) that is identical or similar in composition takes place when a minimum amount of the gas fraction ( 4 ) obtained in the separation (D) of the refrigerant mixture is not reached.  
     
     
         3 . Process for liquefaction of a hydrocarbon-rich stream according to  claim 1 , wherein the gas fraction ( 9 ) that is identical or similar in composition is withdrawn at a point of the refrigerant mixture circuit that is suitable for this purpose and that has a refrigerant mixture that is separated into a gaseous fraction ( 4 ) and a liquid fraction ( 3 ).