APPARATUS AND METHOD FOR RELIQUEFYING BOIL-OFF GAS, AND LNG CARRIER WITH THE APPARATUS

摘要

A boil-off gas reliquefying device and a method, and an LNG(Liquefied Natural Gas) carrier equipped with the device are provided to cool down boil-off gas without increasing the entire load of the boil-off gas reliquefying device and load of a refrigeration system by lowering the temperature of high-temperature boil-off gas by using the low-temperature boil-off gas exhausted from an LNG storage tank. A boil-off gas reliquefying device is composed of a compression unit(30) installed in the middle of a boil-off gas exhaust line(L1) connected from an LNG storage tank(1) to a liquefying heat exchanger to compress the boil-off gas generated in the LNG storage tank and to send the compressed boil-off gas to the liquefying heat exchanger; a supercharger(132) mounted on the boil-off gas exhaust line formed between the LNG storage tank and the compression unit; a precooling heat exchanger(140) installed at the boil-off gas exhaust line formed between the compression unit and the supercharger; and a compressed boil-off gas return line(L4) connected from an output stage of the compression unit to the precooling heat exchanger to exchange heat between the boil-off gas compressed in the compression unit and the boil-off gas generated from the LNG storage tank.