FUEL GAS SUPPLY SYSTEM AND RELIQUEFIED METHOD FOR BOIL OFF GAS

摘要

PURPOSE: A fuel gas supply system and a BOG(boil off gas) re-liquefaction method thereof are provided to guarantee the effective re-liquefaction without a waste of energy because a part of high-pressure BOG is re-liquefied with recovered cold heat from low-pressure BOG. CONSTITUTION: A fuel gas supply system comprises a low-pressure BOG transfer line(11), a compressor(20), a fuel gas supply line(23), a high-pressure BOG transfer line(24), a cold energy recovery and heat exchanger unit(10). The low-pressure BOG transfer line transfers low-pressure BOG generated from a liquefaction plant. The compressor is installed in a lower part of the low-pressure BOG transfer line and compresses the low pressure BOG. The fuel gas supply line and the high pressure BOG transfer line are connected to one and the other side of the compressor each other. The cold energy recovery and heat exchanger unit is installed in the middle of the high-pressure BOG transfer line. The low-pressure BOG transfer line is connected to the cold energy recovery and heat exchanger unit, the low pressure BOG and the high pressure BOG are heat-exchanged.