A ship comprises: a tank; a multistage compressor for compressing a boil-off gas discharged from a storage tank and comprising a plurality of compression cylinders; a first heat exchanger for heat exchanging a fluid, which has been compressed by the multistage compressor, with the boil-off gas discharged from the storage tank and thus cooling the same; a first decompressing device for expanding a flow (flow a1) partially branched from the flow (flow a) that has been cooled by the first heat exchanger; a third heat exchanger for heat exchanging, by flow a1 which has been expanded by the first decompressing device as a refrigerant, the remaining flow (flow a2) of flow a after excluding flow a1 that has been branched and thus cooling the same; and a second decompressing device for expanding flow a2 which has been cooled by the third heat exchanger.

A ship comprises: a liquefied gas storage tank; a multi-stage compressor for compressing a boil-off gas discharged from a storage tank and comprising a plurality of compression cylinders; a second heat exchanger for heat exchanging a fluid, which has been compressed by the multi-stage compressor, and thus cooling same; a first decompressing device for expanding a flow (flow a1) partially branched from the flow (flow a) that has been cooled by the second heat exchanger; a third heat exchanger for heat exchanging, by flow a1 which has been expanded by the first decompressing device as a refrigerant, the remaining flow (flow a2) of flow a after excluding flow a1 that has been branched and thus cooling same; and a second decompressing device for expanding flow a2 which has been cooled by the third heat exchanger.

A vapor pressure regulation system includes a vessel including a vessel wall that defines an enclosure, and a temperature adjustment mechanism coupled to the vessel. A heat transfer between the temperature adjustment mechanism and the vessel is adjusted based on at least a vapor pressure within the vessel to facilitate regulating the vapor pressure within the vessel.

Disclosed herein are a system and method which can control the generation rate of boil-off gas from liquefied hydrogen and can maintain the liquefied hydrogen storage tank at a low pressure. The method for controlling boil-off gas from liquefied hydrogen according to the present invention includes: at least two storage tanks storing liquefied hydrogen and each operated in a high-temperature mode or in a low-temperature mode, wherein the low-temperature mode includes: maintaining at least a portion of liquefied hydrogen stored in the storage tank at a first temperature being a densification temperature, and the high-temperature mode includes: maintaining at least a portion of liquefied hydrogen stored in the storage tank at a second temperature being a temperature exceeding a triple point of liquefied hydrogen through recovery of cold heat from liquefied hydrogen stored in the storage tank.

Disclosed is a method of discharging lubricant oil from a BOG reliquefaction system configured to reliquefy BOG by compressing the BOG by a compressor, cooling the compressed BOG through heat exchange with non-compressed BOG by a heat exchanger, and reducing a pressure of fluid cooled through heat exchange by a pressure reducer. In the lubricant oil discharge method, the compressor comprises at least one oil-lubrication type cylinder and it is determined that it is time to discharge condensed or solidified lubricant oil, if at least one of preset conditions is satisfied.

A power-saving type liquefied-gas-fuel ship includes: a liquefied gas storage tank storing liquefied gas; an engine using the liquefied gas stored in the liquefied gas storage tank or boil-off gas generated by spontaneous vaporization of the liquefied gas as fuel; a fuel feeder supplying the liquefied gas as fuel for the engine; a compressor compressing the boil-off gas to a pressure required for the engine; a heat exchanger cooling the remaining boil-off gas not supplied to the engine among the boil-off gas compressed by the compressor; a refrigerant circulation line in which the refrigerant supplied to the heat exchanger circulates; a refrigerant compressor compressing the refrigerant discharged from the heat exchanger after heat exchange in the heat exchanger; and a cold heat recovery device recovering cold heat of the liquefied gas supplied as fuel for the engine to cool the refrigerant compressed by the refrigerant compressor.

A system and a method with boil-off management for liquefied fuel storage are provided. The system includes a cryotank for storing a liquefied fuel, a pump for providing and compressing a first stream of the liquefied fuel, a heat exchanger for provide cooling duty to the first stream of the liquefied fuel, and an expansion valve for expanding the first stream of the liquefied fuel after the heat exchanger into a multiphase stream comprising a liquid phase and a gas phase. The multiphase stream has a temperature lower than an initial temperature of the first stream from the cryotank. The system further comprises a liquid-vapor splitter for separating the liquid phase and gas phase in the multiphase stream. The liquid phase is returned into the cryotank.

A vessel includes an engine; a first self-heat exchanger for heat-exchanging boil-off gas discharged from a storage tank; a multi-stage compressor for compressing, in multi-stages, the boil-off gas, which has passed through the first self-heat exchanger after being discharged from the storage tank; a first decompressor for expanding a portion of the boil-off gas, which has passed through the first self-heat exchanger after being compressed by the multi-stage compressor; a second decompressor for expanding the other portion of the boil-off gas, which has passed through the first self-heat exchanger after being compressed by the multi-stage compressor; and a second self-heat exchanger for heat-exchanging and cooling the portion of the boil-off gas, which has been compressed by the multi-stage compressor, by using, as a refrigerant, a fluid which has been expanded by the first decompressor.

A method for managing boil-off from an LNG tank located on board of an aircraft. The method, including removing the boil-off from the aircraft and disposing of the removed boil-off from the aircraft and an equipment assembly for use with an aircraft having an on-board LNG tank with a vent system having an outlet coupling, including a removal system configured to remove boil-off from the aircraft and a disposal system configured to dispose of the boil-off.

A vessel comprising an engine comprises: a first self-heat exchanger for heat-exchanging boil-off gas discharged from a storage tank; a multi-stage compressor for compressing, in multi-stages, the boil-off gas, which has passed through the first self-heat exchanger after being discharged from the storage tank; a second self-heat exchanger for precooling the boil-off gas compressed by the multi-stage compressor; a first decompressor for expanding a portion of a fluid which has been cooled by the second self-heat exchanger and the first self-heat exchanger; and a second decompressor for expanding the other portion of the fluid which has been cooled by the second self-heat exchanger and the first self-heat exchanger.