BOIL-OFF GAS TREATMENT APPARATUS FOR ELECTRIC-PROPELLED LNG CARRIER HAVING RE-LIQUEFACTION FUNCTION AND METHOD THEREOF

摘要

The present invention relates to a boil-off gas treatment apparatus for an electric-propelled LNG carrier having a re-liquefaction function and a method thereof comprising: a boil-off gas cooler (10) which receives natural boil-off gas (N-BOG) produced in an LNG cargo tank and cools the gas through heat exchange with a coolant, a gas compressor (20) which receives the cooled N-BOG from the boil-off gas cooler (10) and compresses the gas to a pressure suitable for use in a DFDE (Duel Fuel Diesel Electric) propelled engine (3), an engine feed gas cooler (30) which cools the N-BOG, whose temperature has risen passing through the gas compressor (20), to a temperature suitable for use in the DFDE propelled engine (3) and supplies the cooled gas to the DFDE propelled engine (3), and a re-liquefaction heat exchanger (50) which receives the extra N-BOG unused in the DFDE propelled engine (3) from the downstream of the engine feed gas cooler (30) and supplies the gas to the LNG cargo tank after cooling and re-liquefying through heat exchange with a coolant. The present invention re-liquefies the extra gas unused for propulsion as well as using the natural boil-off gas produced in the LNG cargo tank as a drive source for propelling a vessel, thereby minimizing the waste of N-BOG.