Disclosed is a re-liquefying device using a boil-off gas as a cooling fluid so as to re-liquefy the boil-off gas generated from a liquefied gas storage tank provided in a ship. A boil-off gas re-liquefying device for a ship comprises: a multi-stage compression unit for compressing boil-off gas generated from a liquefied gas storage tank; a heat exchanger in which the boil-off gas generated from the storage tank and the boil-off gas compressed exchange heat; a vaporizer for heat exchanging the boil-off gas cooled by the heat exchanger and a separate liquefied gas supplied to a fuel demand source of a ship, and thus cooling the boil-off gas; an intermediate cooler for cooling the boil-off gas that has been cooled by the heat exchanger; and an expansion means for branching a part of the boil-off gas, which is supplied to the intermediate cooler, and expanding the same.

Provided is a reliquefaction device with which a gas gasified from a liquid can be efficiently reliquefied. A plurality of flow passages include: a mixing flow passage which is connected to the downstream end section of one among a liquid flow passage and a gas flow passage and allows a fluid mixture to flow so that a reliquefaction promoting liquid flowing through the liquid flow passage and a reliquefaction target gas flowing through the gas flow passage are mixed and the reliquefaction of the reliquefaction target gas is promoted by direct heat exchange; and a gas cooling flow passage which allows a coolant to flow and cool the reliquefaction target gas by means of indirect heat exchange with the reliquefaction target gas through a separation wall, thereby suppressing the gasification of the reliquefaction promoting liquid when the reliquefaction target gas is mixed with the reliquefaction promoting liquid flowing through the liquid flow passage.

A new LNG vessel for carrying smaller shipments of LNG to locations that have limited access including rivers and shallow harbors with a low water depth, with a capability to handle boil-off gas, is described. The LNG vessel includes a bilobe or other C-type LNG storage tank, at least one LNG vaporizer, at least one water pump, and at least one LNG pump system on the main cargo platform. The LNG vessel further includes a system for re-condensing boil-off gas.

A device for processing boil-off gas in a liquefied gas regasification system includes a fuel compressor for compressing boil-off gas at a pressured required by a fuel consumer; a high-pressure compressor installed at the rear end of the fuel compressor in series with the fuel compressor so as to compress the low-pressure boil-off gas, which has been compressed by the fuel compressor, at a pressure required by a regasified gas consumer; a low-temperature heat exchanger for cooling the high-pressure boil-off gas compressed by the high-pressure compressor; a pressure-reducing device for reducing the pressure of the high-pressure boil-off gas, which has been cooled by the low-temperature heat exchanger, to the inner pressure of a liquefied gas storage tank for storing the liquefied gas; and a liquefied gas drum for separating flash gas generated by the pressure-reducing device in the pressure-reducing process.

A vessel includes a heat exchanger for heat-exchanging compressed boil-off gas (hereinafter, referred to as first fluid) by using, as a refrigerant, the boil-off gas discharged from a storage tank, to cool the same; a main compression part for compressing a part of the boil-off gas discharged from the storage tank; a rest compression part provided in parallel to the main compression part so as to compress the other part of the boil-off gas discharged from the storage tank; and a decompression device for expanding the first fluid having been cooled by exchanging heat with the boil-off gas, which is discharged from the storage tank, in the heat exchanger. The first fluid is a flow in which the boil-off gas compressed by the main compression part and the boil-off gas compressed by the rest compression part join; or the boil-off gas compressed by the main compression part.

A fuel system for a liquefied gas drive system. The fuel system has a liquefied gas tank and a cooling system for the vaporized content of liquefied gas, which comprises a liquid nitrogen tank, a nitrogen pump, a heat exchanger, and a nitrogen cooler, which are connected to each other in a pipework circuit. The heat exchanger is arranged in the interior of the liquefied gas tank. Also disclosed are a vehicle, a plant and a machine, in each case with a fuel system, and a method for cooling the vaporized content of liquefied gas of a liquefied gas drive system.

The device (100) for providing liquefied natural gas, referred to as LNG, comprises: an evaporation gas buffer tank (105) comprising an inlet (110) for evaporation gas suitable for receiving evaporation gas from a third-party device, a member (115) for transferring evaporation gas from the buffer tank to an LNG storage capacity (120), downstream from the transfer member (120), a compressor (140) for compressing the evaporation gas, an evaporation gas transfer pipe (125) for transferring evaporation gas from the transfer member to the storage capacity, the LNG storage capacity, an LNG transfer pipe (130) for transferring LNG from the storage capacity to a third-party device and a heat exchanger (135) for exchanging heat between evaporation gas passing through the evaporation gas transfer pipe and LNG passing through the LNG transfer pipe configured to liquefy or cool the evaporation gas.

A system is described wherein a cryogenic liquid transport fluid is used as in thermal communication with a volatile gas as a second cryogenic liquid. The volatile gas in the liquid state enables transport of additional volatile substances that cannot be transported in the liquid state employing only the cryogenic liquid. The thermal communication between cryogenic liquids is a thermal cascade.

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 fuel-filling system of an LPG vehicle is provided. LPG remaining in an LPG bombe is forcibly fed to a fuel injection pipe using a fuel pump and is used to pressurize new LPG, which is injected into the fuel injection pipe, toward the LPG bombe. Thus, the LPG bombe is refilled with new LPG despite warmer weather conditions.