Lng production system equipped with recondenser

Abstract

An LNG production system including a boil off gas recondenser that can recondense boil off gas without using a BOG compressor and without depending on an LNG liquefaction process is provided.

1 - 12 . (canceled) 
     
     
         13 . An LNG production system, comprising:
 a liquefier that cools and liquefies natural gas by indirect heat exchange with a refrigerant that is fed from a first refrigerator;   an LNG tank that stores liquid natural gas liquefied in the liquefier;   a transfer line for transferring the liquid natural gas from the LNG tank to an LNG carrier;   a recondenser that recondenses boil off gas that is generated by the liquid natural gas, the recondensing performed by indirect heat exchange with the refrigerant fed from a second refrigerator; and   a return line that feeds the recondensed boil off gas to the LNG tank from the recondenser.   
     
     
         14 . The LNG production system of  claim 13 , wherein the first refrigerator and the second refrigerator are the same. 
     
     
         15 . The LNG production system of  claim 13 , wherein the first refrigerator and the second refrigerator are different. 
     
     
         16 . The LNG production system of  claim 13 , wherein the recondenser switches to perform, alternately, a first recondensation in a recondenser that recondenses boil off gas that is generated by the liquid natural gas, the recondensing performed by indirect heat exchange with the refrigerant fed from a second refrigerator, and a second recondensation wherein the boil off gas is recondensed by indirect heat exchange with the refrigerant from the second refrigerator and refrigerant from a refrigerant buffer, thereby processing more boil off gas than the boil off gas at a time of the first recondensation processing. 
     
     
         17 . The LNG production system of  claim 13 , wherein the recondenser is designed to recondense the boil off gas by a refrigerant under a pressure lower than an operating pressure of the LNG tank. 
     
     
         18 . The LNG production system of  claim 13 , wherein the recondenser is internally provided with a heat exchanger in which the refrigerant is introduced, and the boil off gas is introduced into the heat exchanger, and is cooled by the refrigerant. 
     
     
         19 . The LNG production system of  claim 18 , wherein an external capacity of the heat exchanger is smaller than an internal space capacity of the recondenser, and the heat exchanger is disposed in the internal space of the recondenser. 
     
     
         20 . A recondenser within an LNG production system that liquefies natural gas to produce liquid natural gas, and recondenses boil off gas in an LNG tank in which the liquid natural gas that is liquefied is stored, by a refrigerant, the condenser comprising:
 a return line that directly feeds liquid natural gas that is recondensed to the LNG tank.   
     
     
         21 . The recondenser of  claim 20 , wherein the recondenser is designed to recondense the boil off gas by a refrigerant under a pressure lower than an operating pressure of the LNG tank. 
     
     
         22 . The recondenser of  claim 20 , wherein the recondenser is internally provided with a heat exchanger in which the refrigerant is introduced, and the boil off gas is introduced into the heat exchanger, and is cooled by the refrigerant. 
     
     
         23 . The recondenser of  claim 22 , wherein an external capacity of the heat exchanger is smaller than an internal space capacity of the recondenser, and the heat exchanger is disposed in the internal space of the recondenser.