LIQUEFIED GAS TREATMENT SYSTEM
A liquefied gas treatment system according to an embodiment of the present invention includes a boil-off gas heat exchanger exchanging heat between boil-off gas, pressurized by a boil-off gas compressor and recovered along a boil-off gas supply line branching off upstream of a liquefied gas-consuming unit, and the boil-off gas supplied from a liquefied gas storage tank, wherein the boil-off gas heat exchanger cools the boil-off gas, recovered along the boil-off gas supply line, with the boil-off gas, supplied from the liquefied gas storage tank, or flash gas, supplied through a vapor recovery line.
1 . A liquefied gas treatment system, comprising:
a boil-off gas supply line connected from a liquefied gas storage tank to a liquefied gas-consuming unit;
a boil-off gas compressor provided on the boil-off gas supply line and pressurizing boil-off gas generated from the liquefied gas storage tank;
a boil-off gas heat exchanger provided upstream of the boil-off gas compressor on the boil-off gas supply line and exchanging heat between the boil-off gas, pressurized by the boil-off gas compressor and recovered along the boil-off gas supply line branching off upstream of the liquefied gas-consuming unit, and the boil-off gas supplied from the liquefied gas storage tank;
a boil-off gas decompressor provided downstream of the boil-off gas heat exchanger on the basis of a flow of the boil-off gas, recovered along the boil-off gas supply line, and decompressing the boil-off gas compressed by the boil-off gas compressor;
a vapor-liquid separator separating flash gas from the boil-off gas decompressed by the boil-off gas decompressor; and
a vapor recovery line connected from the vapor-liquid separator to the boil-off gas heat exchanger and supplying the flash gas to the boil-off gas heat exchanger,
wherein the boil-off gas heat exchanger cools the boil-off gas, recovered along the boil-off gas supply line, with the boil-off gas, supplied from the liquefied gas storage tank, or the flash gas, supplied through the vapor recovery line.
2 . The liquefied gas treatment system of claim 1 , wherein the boil-off gas, heat-exchanged by the boil-off gas heat exchanger, is supplied to the boil-off gas decompressor or the boil-off gas compressor.
3 . The liquefied gas treatment system of claim 1 , wherein the flash gas, heat-exchanged by the boil-off gas heat exchanger, is supplied to and combusted in a gas combustion unit combusting fuel.
4 . The liquefied gas treatment system of claim 1 , further comprising a mixer provided upstream of the boil-off gas heat exchanger on the boil-off gas supply line, mixing the boil-off gas, supplied from the liquefied gas storage tank, with the flash gas, recovered from the vapor-liquid separator, and supplying mixed gases to the boil-off gas heat exchanger,
wherein the flash gas, heat-exchanged by the boil-off gas heat exchanger, is supplied to the mixer.
5 . The liquefied gas treatment system of claim 1 , further comprising a liquid recovery line connected from the vapor-liquid separator to the liquefied gas storage tank and recovering the boil-off gas in liquid state, separated by the vapor-liquid separator, to the liquefied gas storage tank.
6 . The liquefied gas treatment system of claim 1 , wherein the boil-off gas decompressor is a Joule-Thomson valve.
7 . The liquefied gas treatment system of claim 1 , further comprising a flash gas bypass line branching off from the vapor recovery line and allowing at least part of the flash gas, exhausted from the vapor-liquid separator, to bypass the boil-off gas heat exchanger.