A BOG RE-LIQUEFACTION SYSTEM AND METHOD FOR LNG CARRIER

摘要

A system for BOG(Boil Off Gas) re-liquefaction of an LNG(Liquefied Natural Gas) carrier is provided to reduce the system as a whole by sequentially passing BOG through heat exchangers and self-heat exchangers in a plurality of general refrigeration cycles for BOG re-liquefaction, and to greatly reduce power consumption and increase efficiency of the whole system by using general refrigeration cycles using a relatively small amount of refrigerant, and a method for BOG re-liquefaction of the LNG carrier using the system is provided. A system for BOG(Boil Off Gas) re-liquefaction of an LNG(Liquefied Natural Gas) carrier comprises: a BOG compressor(10) compressing BOG generated when LNG stored in a storage tank is vaporized by heat penetrated into the storage tank from the outside; a distributor(20) for supplying a portion of the compressed BOG to a DF(Dual Fuel) engine and supplying the residual compressed BOG to a re-liquefaction unit; refrigeration cycles(40,60,70) for cooling the BOG supplied to the re-liquefaction unit; and an expansion valve(90) for subjecting the cooled BOG to adiabatic expansion to change the phase of the BOG from gas to liquid.