System for supplying fuel to high-pressure natural gas injection engine having excess evaporation gas consumption means

Abstract

Provided is a fuel supply system for a high-pressure natural gas injection engine. The fuel supply system includes: a BOG compression unit configured to receive BOG, which is generated in a storage tank, from the storage tank and compress the received BOG to a pressure of 12 to 45 bara; a reliquefaction apparatus configured to receive and liquefy the BOG compressed by the BOG compression unit; a high-pressure pump configured to compress the BOG liquefied by the reliquefaction apparatus; a high-pressure gasifier configured to gasify the BOG compressed by the high-pressure pump and supply the gasified BOG to the high-pressure natural gas injection engine; and an excess BOG consumption unit configured to consume excess BOG corresponding to a difference between an amount of BOG generated in the storage tank and an amount of BOG required as fuel for the high-pressure natural gas injection engine.

What is claimed is: 
     
         1 . A fuel supply system for a high-pressure natural gas injection engine, comprising:
 a boil-off gas (BOG) compression unit configured to receive BOG, which is generated in a storage tank, from the storage tank and compress the received BOG to a pressure of 12 to 45 bara;   a reliquefaction apparatus configured to receive and liquefy the BOG compressed by the BOG compression unit;   a high-pressure pump configured to compress the BOG liquefied by the reliquefaction apparatus;   a high-pressure gasifier configured to gasify the BOG compressed by the high-pressure pump and supply the gasified BOG to the high-pressure natural gas injection engine; and   an excess BOG consumption unit configured to consume excess BOG corresponding to a difference between an amount of BOG generated in the storage tank and an amount of BOG required as fuel for the high-pressure natural gas injection engine.   
     
     
         2 . The fuel supply system according to  claim 1 , wherein the excess BOG consumption unit is a gas combustion unit configured to receive flash gas through a fuel gas supply line and consume the received flash gas as fuel. 
     
     
         3 . The fuel supply system according to  claim 1 , wherein the excess BOG consumption unit is a dual-fuel diesel engine configured to receive BOG through a branch line branching in the middle of the BOG compression unit and consume the received BOG as fuel. 
     
     
         4 . The fuel supply system according to  claim 1 , wherein the excess BOG consumption unit is a gas turbine configured to receive BOG through a branch line branching from a rear end of the BOG compression unit and consume the received BOG as fuel. 
     
     
         5 . The fuel supply system according to  claim 1 , further comprising:
 an LBOG return line configured to return the excess BOG to the storage tank; and   a gas-liquid LBOG separator installed at the LBOG return line and configured to separate BOG including flash gas into a liquid component and a gaseous component and return only the liquid component to the storage tank, the flash gas being generated in a decompression process when the excess BOG is returned to the storage tank.   
     
     
         6 . The fuel supply system according to  claim 5 , further comprising an LBOG expansion valve installed at the LBOG return line and configured to decompress the excess BOG. 
     
     
         7 . The fuel supply system according to  claim 6 , further comprising a valve installed at the fuel gas supply line and configured to decompress the gaseous component separated by the gas-liquid LBOG separator. 
     
     
         8 . The fuel supply system according to  claim 2 , further comprising a branch line branching from the fuel supply line supplying fuel to the high-pressure natural gas injection line, and connected to the fuel gas supply line supplying the fuel to the dual-fuel diesel engine, such that the fuel is additionally supplied to the gas combustion unit.