APPARATUS AND METHOD FOR REDUCING PRESSURE RISE OF LNG CARGO TANK OF LNG CARRIER WITH FUEL GAS PROPULSION MEANS

摘要

An apparatus for reducing pressure increase of an LNG cargo tank of an LNG carrier with a fuel gas propulsion unit is provided to reduce waste of boil-off gas by allowing increase of vapor pressure and LNG temperature inside the LNG cargo tank during LNG transportation. An apparatus for reducing pressure increase of an LNG cargo tank of an LNG carrier with a fuel gas propulsion unit comprises a boil-off gas divergence line and an LNG cargo tank(1). The boil-off gas divergence line for returning compressed boil-off gas to the LNG cargo tank is installed in a fuel supply line for compressing the boil-off gas of an upper portion of the LNG cargo tank and supplying the boil-off gas as the fuel gas propulsion unit. Some of the compressed boil-off gas is returned to the LNG cargo tank when fuel gas consumption amount of the fuel gas propulsion unit is little or nonexistent.