Abstract: In a BOG treatment system, boil-off gas (BOG) discharged from a storage tank is compressed, most of the BOG is used as the fuel of vessel engines, and a remaining part of the BOG is liquefied by cold energy of BOG newly discharged from the storage tank and is returned to the storage tank, thereby efficiently utilizing the BOG. The BOG treatment system for a vessel includes a compressor compressing the BOG discharged from the storage tank; a medium pressure gas engine receiving at least a part of the BOG compressed by the compressor, as fuel; a heat exchanger exchanging heat between the remaining part of the BOG, which is not supplied to the medium pressure gas engine as fuel, and the BOG, which is discharged from the storage tank and is not compressed; and an expander decompressing the remaining part of the BOG cooled by the heat exchanger.

Abstract: A system for supplying fuel to an engine of a ship. The system includes a high pressure pump pressurizing a liquefied natural gas (LNG) and supplying the pressurized LNG to the engine, a hydraulic motor driving the high pressure pump and a chamber carrying the high pressure pump and the hydraulic motor. The chamber is substantially free of electric sparks.

Abstract: Disclosed herein are an apparatus and a method for supplying a fuel to an engine of a ship. The apparatus for supplying a fuel to an engine of a ship includes: a high pressure pump pressurizing a liquefied natural gas (LNG) and supplying the pressurized LNG to the engine; a hydraulic motor driving the high pressure pump; and a lubricating pump supplying lubricating oil to the high pressure pump.

Abstract: Disclosed herein is a boil-off gas treatment system. The boil-off gas treatment system includes a compressor compressing boil-off gas generated in an LNG storage tank of a ship or a floating structure, a heat exchanger cooling the compressed boil-off gas through heat exchange with boil-off gas to be supplied to the compressor, an expansion unit performing adiabatic expansion of the boil-off gas cooled by the heat exchanger, a gas-liquid separator performing gas/liquid separation of the boil-off gas subjected to adiabatic expansion by the expansion unit and supplying liquefied natural gas to the LNG storage tank, and a bypass line through which the boil-off gas subjected to adiabatic expansion is supplied from a downstream side of the expansion unit to a downstream side of the gas-liquid separator.

Abstract: A pump for supplying a cryogenic liquid coolant in accordance with the present invention includes: a housing having an inlet port for introducing a cryogenic liquid coolant, an outlet port for discharging the cryogenic liquid coolant introduced through the inlet port, and a chamber for connecting the inlet port and the outlet port; an impeller rotatably retained in the housing for introducing the cryogenic liquid coolant through the inlet port and discharging the same through the outlet port; and a vapor exhausting part provided in the housing for exhausting vapor generated from the cryogenic liquid coolant.

Abstract: In a BOG treatment system, boil-off gas (BOG) discharged from a storage tank is compressed, most of the BOG is used as the fuel of vessel engines, and a remaining part of the BOG is liquefied by cold energy of BOG newly discharged from the storage tank and is returned to the storage tank, thereby efficiently utilizing the BOG. The BOG treatment system for a vessel includes a compressor compressing the BOG discharged from the storage tank; a medium pressure gas engine receiving at least a part of the BOG compressed by the compressor, as fuel; a heat exchanger exchanging heat between the remaining part of the BOG, which is not supplied to the medium pressure gas engine as fuel, and the BOG, which is discharged from the storage tank and is not compressed; and an expander decompressing the remaining part of the BOG cooled by the heat exchanger.

Abstract: Provided is a method for operating a fuel supply system for a marine structure. The fuel supply system includes a BOG compression unit configured to receive and compress BOG generated in a storage tank, a reliquefaction apparatus configured to receive and liquefy the BOG compressed by the BOG compression unit, a high-pressure pump configured to compress the liquefied BOG generated by the reliquefaction apparatus, and a high-pressure gasifier configured to gasify the liquefied BOG compressed by the high-pressure pump. The fuel supply system includes a recondenser installed at an upstream side of the high-pressure pump, and the recondenser recondenses a portion or all of the generated BOG by using liquefied gas supplied from the storage tank. During a ballast voyage process, all of the BOG is supplied to and recondensed by the recondenser, and an operation of the reliquefaction apparatus is interrupted.

Abstract: A system for supplying fuel to an engine of a ship. The system includes a high pressure pump pressurizing a liquefied natural gas (LNG) and supplying the pressurized LNG to the engine, a hydraulic motor driving the high pressure pump and a chamber carrying the high pressure pump and the hydraulic motor. The chamber is substantially free of electric sparks.

Abstract: Disclosed herein are an apparatus and a method for supplying a fuel to an engine of a ship. The apparatus for supplying a fuel to an engine of a ship includes: a high pressure pump pressurizing a liquefied natural gas (LNG) and supplying the pressurized LNG to the engine; a hydraulic motor driving the high pressure pump; and a lubricating pump supplying lubricating oil to the high pressure pump.

Abstract: A superconducting rotating machine having a cooler for a rotator is provided. The superconducting rotating machine includes a rotator wound with a superconducting coil, a stator enclosing the rotator and separated therefrom by a predetermined gap, the cooler having a cold head directly attached to the rotator and at least one compressor connected with the cold head, and a flexible coupling disposed between the cold head and the compressor and enabling a cryogenic refrigerant to flow therein. The cold head is directly connected to the rotator, and the cold head and the compressor are driven using the flexible coupling, so that it is possible to prevent vibration of the compressor and enhance cooling efficiency by thermally separating the cryogenic cold head from the compressor.

Abstract: The rotary type ultralow temperature refrigerant supply apparatus includes a refrigerant introduction pipe coupled to the super conductive rotor for supplying a liquid-phase ultralow temperature refrigerant cooled by the refrigeration system to the evaporator, a refrigerant withdrawal pipe disposed spaced apart from the refrigerant introduction pipe for withdrawing a gas-phase ultralow temperature refrigerant obtained through the evaporation of the liquid-phase refrigerant by the evaporator and guiding the withdrawn gas-phase ultralow temperature refrigerant to the refrigeration system, and a vacuum housing fixedly disposed outside the refrigerant introduction pipe and the refrigerant withdrawal pipe, the vacuum housing having a vacuum heat insulation space defined inside.

Abstract: Provided is a method for operating a fuel supply system for a marine structure. The fuel supply system includes a BOG compression unit configured to receive and compress BOG generated in a storage tank, a reliquefaction apparatus configured to receive and liquefy the BOG compressed by the BOG compression unit, a high-pressure pump configured to compress the liquefied BOG generated by the reliquefaction apparatus, and a high-pressure gasifier configured to gasify the liquefied BOG compressed by the high-pressure pump. The fuel supply system includes a recondenser installed at an upstream side of the high-pressure pump, and the recondenser recondenses a portion or all of the generated BOG by using liquefied gas supplied from the storage tank. During a ballast voyage process, all of the BOG is supplied to and recondensed by the recondenser, and an operation of the reliquefaction apparatus is interrupted.

Abstract: Provided is a fuel supply system for a marine structure using a high-pressure natural gas injection engine. The fuel supply system includes: a boil-off gas (BOG) compression unit configured to receive and compress BOG generated in a storage tank storing a liquefied gas; a reliquefaction apparatus configured to receive and liquefy the BOG compressed by the BOG compression unit; a buffer tank configured to receive the liquefied BOG from the reliquefaction apparatus and separate the reliquefied BOG into a gaseous component and a liquid component; a high-pressure pump configured to receive the liquid component from the buffer tank and compress the liquid component; and a high-pressure gasifier configured to gasify the liquid component compressed by the high-pressure pump and supply the gasified liquid component to the high-pressure natural gas injection engine.

Abstract: Provided is a nonflammable mixed refrigerant for use in a reliquefaction apparatus of a fuel supply system that compresses BOG generated in an LNG storage tank to a medium pressure, reliquefies the compressed BOG, compresses the reliquefied BOG to a high pressure, gasifies the compressed requefied BOG, and supplies the gasified BOG to a high-pressure natural gas injection engine. A nonflammable mixed refrigerant for use in a fuel supply system for a high-pressure natural gas injection engine is provided. The nonflammable mixed refrigerant cools the BOG by heat exchange with the BOG in the reliquefaction apparatus. The nonflammable mixed refrigerant comprises a mixture of nonflammable refrigerants with different boiling points, and the boiling point of each of the nonflammable refrigerant ranges between a room temperature and a liquefaction temperature of natural gas.

Abstract: Provided is a fuel supply system for a marine structure. The fuel supply system includes a BOG compression unit configured to receive and compress BOG generated in a storage tank, a reliquefaction apparatus configured to receive and liquefy the BOG compressed by the BOG compression unit, a high-pressure pump configured to compress the liquefied BOG generated by the reliquefaction apparatus, and a high-pressure gasifier configured to gasify the liquefied BOG compressed by the high-pressure pump. The fuel supply system includes a recondenser installed at an upstream side of the high-pressure pump and configured to recondense a portion or all of the generated BOG by using liquefied gas received from the storage tank. The BOG compression unit compresses BOG to a pressure of about 12 to 45 bara such that the BOG is liquefied under the compression pressure of the BOG compression unit.

Abstract: Provided is a fuel supply system for a high-pressure natural gas injection engine. The fuel supply system includes: a BOG compression unit configured to receive BOG, which is generated in a storage tank, from the storage tank and compress the received BOG to a pressure of 12 to 45 bara; a reliquefaction apparatus configured to receive and liquefy the BOG compressed by the BOG compression unit; a high-pressure pump configured to compress the BOG liquefied by the reliquefaction apparatus; a high-pressure gasifier configured to gasify the BOG compressed by the high-pressure pump and supply the gasified BOG to the high-pressure natural gas injection engine; and an excess BOG consumption unit configured to consume excess BOG corresponding to a difference between an amount of BOG generated in the storage tank and an amount of BOG required as fuel for the high-pressure natural gas injection engine.

Abstract: Provided is a fuel supply method for a marine structure using a high-pressure natural gas injection engine. BOG stored in a stored in the storage tank is compressed to a pressure of 12 to 45 bara (absolute pressure) and then reliquefied. A reliquefaction apparatus includes a cold box configured to exchange heat between a refrigerant and the BOG, a compression unit configured to compress the refrigerant heated by the cold box, an expansion unit configured to expand the compressed refrigerant to drop the temperature thereof, and a plurality of gas-liquid refrigerant separators configured to separate the refrigerant into a gaseous refrigerant and a liquid refrigerant. A gaseous refrigerant and a liquid refrigerant separated by the gas-liquid refrigerant separator disposed at an upstream side are again mixed and supplied to the gas-liquid refrigerant separator disposed at the most downstream among the plurality of gas-liquid refrigerant separators.

Abstract: A method for producing pressurized liquefied natural gas and a production system therefor are provided. The method for producing pressurized liquefied natural gas includes: performing a dehydration process to remove water from natural gas supplied from a natural gas field, without a process of removing acid gas from the natural gas; and performing a liquefaction process to produce pressurized liquefied natural gas by liquefying the natural gas, which has undergone the dehydration process, at a pressure of 13 to 25 bar and a temperature of ?120 to ?95° C., without a process of fractionating natural gas liquid (NGL). Accordingly, it is possible to reduce plant construction costs and maintenance expenses and reduce LNG production costs. In addition, it is possible to guarantee high economic profit and reduce payback period in small and medium-sized gas fields, from which economic feasibility could not be ensured by the use of a conventional method.

Abstract: Disclosed is a cooling fluid path structure for a superconducting rotating machine, which includes: a fixed inlet fluid path fixed together with the fluid supply means; a rotating inlet fluid path adjacently connected to an outlet of the fixed inlet fluid path, which is for transferring the cooling fluid transferred from the fixed inlet fluid path to a cooling fluid path inlet provided in the rotor while rotating together with the rotor; a rotating outlet fluid path rotating together with the rotor, to which the cooling fluid discharged from a cooling fluid path outlet of the rotor is transferred; and a fixed outlet fluid path adjacently connected to the rotating outlet fluid path, which is for transferring the cooling fluid transferred from the rotating outlet fluid path to the fluid supply means while being fixed together with the fluid supply means, wherein the rotating outlet fluid path and the fixed outlet fluid path are disposed in such a manner that they surround outside of the rotating inlet fluid pat

Abstract: Disclosed is a cooling fluid path structure for a superconducting rotating machine, which includes: a fixed inlet fluid path fixed together with the fluid supply means; a rotating inlet fluid path adjacently connected to an outlet of the fixed inlet fluid path, which is for transferring the cooling fluid transferred from the fixed inlet fluid path to a cooling fluid path inlet provided in the rotor while rotating together with the rotor; a rotating outlet fluid path rotating together with the rotor, to which the cooling fluid discharged from a cooling fluid path outlet of the rotor is transferred; and a fixed outlet fluid path adjacently connected to the rotating outlet fluid path, which is for transferring the cooling fluid transferred from the rotating outlet fluid path to the fluid supply means while being fixed together with the fluid supply means, wherein the rotating outlet fluid path and the fixed outlet fluid path are disposed in such a manner that they surround outside of the rotating inlet fluid pat