Abstract: A liquefied gas reliquefier reliquefies boil-off gas resulting from evaporation of liquefied gas in a liquefied-gas storage tank to prevent a rise in the internal pressure of the liquefied-gas storage tank. The liquefied gas reliquefier includes a cooling unit for liquefying a secondary refrigerant, a liquefied-secondary-refrigerant feeding unit for feeding the liquefied secondary refrigerant, and a heat exchange unit disposed in the secondary-refrigerant circulating channel to condense the BOG by heat exchange between the BOG and the liquefied secondary refrigerant. The heat exchange unit is disposed near the liquefied-gas storage tank. The cooling unit includes a plurality of pulse-tube refrigerators. The number of pulse-tube refrigerators in operation and/or the cooling capacities of the individual pulse-tube refrigerators are controlled based on a measurement result from at least one of a thermometer, a pressure gauge, and a pump discharge flow meter installed in the liquefied-gas storage tank.

Abstract: A liquefied gas reliquefier that can be configured compactly and that is easy to handle is provided. A liquefied gas reliquefier (1) reliquefies BOG resulting from evaporation of LNG in a cargo tank (3). The liquefied gas reliquefier (1) includes a refrigerator group (20) disposed in a secondary-refrigerant circulating channel (24) through which nitrogen, which has a lower condensation temperature than the BOG, circulates to liquefy the nitrogen; a feed pump (22) for feeding the liquid nitrogen cooled by the refrigerator group (20) through the secondary-refrigerant circulating channel (24); and a heat exchanger (12) disposed in the secondary-refrigerant circulating channel (24) to condense the BOG by heat exchange between the BOG and the liquid nitrogen fed by the feed pump (22). The heat exchanger (12) is disposed near the cargo tank (3).