Abstract: A method of expansive-cooling an amount of a natural gas during transfer from a first storage container to a second storage container is provided. In addition, a system including two storage containers connected by an expander for the expansion of natural gas during the transfer from the first storage container to the second storage container is provided.

Abstract: A system for dispensing cryogenic liquid to a use point includes a bulk tank containing a supply of cryogenic liquid and a pressure builder that is in communication with the tank via a pressure building valve. The pressure builder uses heat exchangers to vaporize a portion of the cryogenic liquid as needed to pressurize the bulk tank. The pressurized cryogenic liquid is dispensed through a dispensing line running from the bottom of the tank. A vent valve also vents vapor from the tank to control pressure. Operation of the vent and pressure building valves is automated by a controller that receives data from sensors. The controller determines the required saturation pressure for the tank and varies the tank pressure to match and provide a generally constant outlet pressure depending on conditions of the cryogenic liquid.

Abstract: The invention relates to a cooling apparatus, especially for cryogenically preserving biological samples, comprising a duct (5) for delivering a coolant (3) to a cooling chamber (1), a heater (6) that has an adjustable first heating performance (P2) for heating the coolant (3) delivered to the cooling chamber (1), a first temperature sensor (8-10) for measuring the temperature (T2-T4) in the cooling chamber (1), a second temperature sensor (7) for measuring the temperature (T1) of the coolant (3) delivered to the cooling chamber (1), and a regulator (11) for regulating the temperature. Said regulator (11) is embodied as a multiple regulator which detects several temperatures (T1-T4) as control variables and/or adjusts several heating performances (P1, P2) as manipulated variables. The invention further relates to a corresponding operating method.

Abstract: Methods and systems for regasifiing LNG are provided. A method for regasifying liquefied natural gas (LNG) includes providing heat to a LNG regasification process from a power plant. If the heat is not sufficient, additional heat can be provided to the LNG regasification process from a cooling tower operated in a warming tower configuration.

Abstract: The disclosure is directed to an energy recovery system for a mobile machine. The energy recovery system may include a tank configured to store a liquid fuel for combustion within an engine of the mobile machine, and a combustor selectively connectable to receive gaseous fuel formed in the tank. The energy recovery system may also include a recovery device operable to generate work using exhaust from the combustor.

Abstract: Described herein are systems and methods for cryogenic fluid delivery. The systems may include a pressure vessel containing a cryogenic fluid formed of liquid and vapor that is connected to a use device via a withdrawal line. The withdrawal line connects to the cryogenic fluid in the pressure vessel via two routes, a liquid tube and a vapor line. The vapor line may include a back-pressure regulator that opens the vapor line depending on pressure in the system. The withdrawal line may include a pressure relief valve that exerts pressure on the liquid tube. A bypass line may connect the withdrawal line to the liquid tube. The bypass line has a check valve that permits free flow of cryogen from the withdrawal line to the liquid tube via the bypass line while prohibiting cryogen flow from the pressure vessel through the bypass line. The methods employ the systems described herein.

Abstract: A handler includes a storage tank which stores liquid nitrogen, supply channels which supply refrigerant from the storage tank to inner passages of a first shuttle, a valve which opens and closes the supply channel, and a heat exchanger which has vaporization chambers with larger flow path cross-sectional areas than those of the supply channels to vaporize liquid nitrogen within the vaporization chambers. According to this structure, the respective vaporization chambers are filled with nitrogen gas produced by preceding vaporization. Thus, pressure fluctuations produced by successive vaporization of liquid nitrogen can be reduced. Moreover, nitrogen gas is supplied to the respective inner passages. Accordingly, excessive cooling for part housing pockets can be prevented.

Abstract: A method for maintaining a subcooled bottom state or the natural convection current of a liquefied natural gas in a storage vessel by the use of an external heat exchanger. The liquefied natural gas is removed from the storage vessel and cooled in the external heat exchanger by a cryogenic fluid such as liquid nitrogen. The cooled liquefied natural gas is reintroduced back into the storage vessel thereby maintaining a subcooled bottom layer or natural convection current in the storage vessel.

Abstract: Methods, apparatuses and systems are disclosed for supplying gas from a multi-container Bulk Specialty Gases Supply System wherein at least one process parameter is automatically monitored to prevent over-filling of at least a first and second container without operator intervention.

Abstract: A portable liquid oxygen (PLOX) unit and method of filling. The LOX unit includes a LOX container. An inlet line communicates LOX from a LOX supply to an the LOX container, and an outlet line communicates LOX from the LOX container ultimately for consumption by a user. A vent line communicate the interior of the LOX container to ambient atmosphere. A vent valve is coupled to the vent line to selectively communicate the LOX container to the ambient atmosphere. An auto shutoff assembly is associated with vent line to substantially block the vent line when the LOX in the LOX container reaches a predetermined level. A reset element associated with the auto shutoff assembly causes at least a portion of the auto shutoff assembly to unblock the vent line for subsequent filling.

Abstract: A device for supplying cold gases to an NMR installation or analytical apparatus equipped with a measuring probe, with cold gases ensuring the cooling of the sample contained in the probe, but also its lift and rotation, the device including an insulated tank containing liquid gas at boiling point and in which are arranged exchangers through which gas streams to be cooled pass, these exchangers being connected to transfer lines channeling the cooled gases to the probe. The device also includes at least one additional exchanger that ensures a pre-cooling of the gas stream before it is channeled to the corresponding exchanger, with the or each additional exchanger coming in the form of a double-flow exchanger that is supplied either by the gaseous vapor produced by the boiling of the liquid gas in the tank or by the cold gas that is evacuated or that escapes at the probe.

Abstract: A cryogen cylinder includes a tank having a side wall defining a chamber for containing a cryogenic substance in the tank; and a plate assembly mounted in the chamber, the plate assembly constructed and arranged to provide a passageway for vapor from the cryogenic substance to be introduced into the passageway.

Abstract: A heat exchanger includes a first housing disposed in a first atmosphere and having an upstream end, a downstream end and an internal space for a cryogenic substance; and a heat plate assembly mounted to the first housing and being exposed to the first atmosphere for providing heat transfer at an interface of the first atmosphere and the heat plate assembly.

Abstract: One embodiment of the present invention is a portable natural gas discharge system for discharging compressed natural gas into a receiving location. The system comprises a portable chassis for holding the natural gas discharge system and all subcomponents, an inlet port for receiving the natural gas at an inlet pressure higher than a pressure of the receiving location, an expansion valve for regulating pressure of the natural gas to a stable intermediate pressure, a heat exchanger for heating up the cooled natural gas stream as a result of cooling due to expansion, a regulator for regulating a flow of the heated natural gas stream through the heat exchanger and out of the portable natural gas discharge system, and a discharge port for discharging the heated natural gas stream into the receiving location.

Abstract: Hydrogen filling station, in particular, for refilling vehicle tanks with hydrogen gas, comprising a source reservoir designed to hold liquid hydrogen (LH2), a pipe for withdrawing liquid hydrogen from the source reservoir to at least one user station, an electric cryogenic pump arranged within the withdrawing pipe and an electric power supply connected to the cryogenic pump to supply the same with electricity, characterized in that the electric energy supply comprises at least one fuel cell.

Abstract: Disclosed is an apparatus for containing LNG. The apparatus includes an LNG tank containing liquid phase LNG and boil-off gas of LNG, and an circulating device. The circulating device includes an intake port and a discharge port. The circulating device further includes an flowing pathway from the intake port to the discharge port that does not include a forced LNG liquefying device. The intake port is located in an upper portion of the LNG tank, and the discharge port is located in a lower portion of the LNG tank substantially lower than the intake port. The circulating device is configured to suction, through the intake port, boil-off gas from the upper portion of the LNG tank and to discharge boil-off gas, through the discharge port, to the lower portion of the LNG tank.

Abstract: A boil-off gas (BOG) stream (15) from a liquefied hydrocarbon storage tank is split into a BOG heat exchanger feed stream (25) and a BOG bypass stream (35). The BOG heat exchanger feed stream (25) is heat exchanged in a BOG heat exchanger (40) against a process stream (135), thereby providing a warmed BOG stream (45) and a cooled process stream (195). The warmed BOG stream (45) is combined with the BOG bypass stream (35) to provide a temperature controlled BOG stream (55).

Abstract: A process and apparatus that includes a cryogenic source for providing a cryogenic fluid for vaporization, a cryogenic pump in fluid flow communication with the cryogenic source for increasing the pressure of the cryogenic fluid, an unfired vaporizer coolant circuit 110 in fluid flow communication with the cryogenic pump and adapted to accept the cryogenic fluid to form a heated stream, a direct-fired vaporizer downstream and in fluid flow communication with the unfired vaporizer coolant circuit 110 and adapted to accept the heated stream from the unfired vaporizer coolant circuit to form a superheated stream; and a diesel engine power unit 118 to provide power to the cryogenic pump, the unfired vaporizer coolant circuit 110, and the direct-fired vaporizer.

Abstract: A Rankine cycle system has a condenser, a refrigerant circulating pump connected to the condenser, a heat collecting device connected to the refrigerant circulating pump, and an expansion turbine connected to the heat collecting device and the condenser. The refrigerant circulating pump includes an expansion tank or pressure vessel, a refrigerant supply conduit connected to the lower part of the expansion tank and to the condenser, and a refrigerant discharge conduit connected to the upper part of the expansion tank. An open/close valve is installed in the refrigerant supply conduit. A pressure regulating valve installed in the refrigerant discharge pipe opens when a pressure reaches a specified value or higher. A temperature regulating device can heat the refrigerant in the expansion tank to produce a refrigerant vapor of saturated temperature or higher, which vapor can be introduced into the heat collecting device.

Abstract: A plant for regasification of LNG includes at least one pump boosting LNG pressure; an LNG/coolant heat exchanger producing NG from LNG being flowed from the boosting pumps; a closed coolant loop extending through the LNG/coolant heat exchanger and including at least one heat exchanger, a coolant from the respective heat exchanger being passed through the LNG heat exchanger as a gas and leaving in a condensed state as to produce NG by thermal exchange; and a heating medium being used within the respective heat exchanger as to provide coolant in a gaseous state. An NG/coolant heat exchanger is arranged in connection with the LNG/coolant heat exchanger and is connected to the closed coolant loop, whereby LNG is preheated within the LNG/coolant heat exchanger and NG is trim heated within the NG/coolant heat exchanger using liquid coolant from at least one heat exchanger.

Abstract: A superconducting magnet assembly and method of cooling a superconducting magnet assembly.

Abstract: A marine vessel, and a system and method of using the marine vessel, to facilitate the introduction of bulk liquid commodities, such as LNG, into the established and extensive worldwide intermodal transportation system, which is based on containerized shipments. The marine vessel is a specialized vessel, of either ship or barge form, that is capable of holding a large number of ISO-sized intermodal LNG tanks and is configured so as to have at one and the same time characteristics of both a tanker vessel (e.g., a gas carrier) and a container vessel.

Abstract: Provided is an apparatus for generating electricity required by an LNG carrier which stores LNG, which is obtained by liquefying natural gas to ultra low temperature in a gas field, in an LNG storage tank and carries the stored LNG. The apparatus includes: a reformer reforming boil-off gas occurring in the LNG storage tank and producing synthetic gas; and a fuel cell generating electricity through an electrochemical reaction of the synthetic gas produced by the reformer.

Abstract: A fluid control assembly is connected between a cold gas container intended to be operated at deep cryogenic temperatures (e.g., 4K) and a gas reservoir for controlling the flow of fluid between the container and the reservoir. The fluid control assembly may be a passive valve assembly or an electrically controlled valve assembly which controls fluid flow between the reservoir and the container as a function of temperature and/or pressure differentials. The fluid control assembly enables the container to be rapidly cooled by restricting the amount of fluid flow from the reservoir into the container when the container is subjected to thermal cycling within a limited temperature range (e.g., 4K to 11K). The fluid control assembly together with the gas reservoir and the container form a thermal damper which is suited for use in a cryocooling system for producing the cryogenic temperatures (e.g., 4K) to operate superconducting devices which may need to be thermally cycled to remove trapped flux.

Abstract: A cryogenic storage tank comprises a partition that divides a cryogen space into a main storage space and an auxiliary space. A valve disposed inside the cryogen space is associated with a first fluid passage through the partition. The valve comprises a valve member that is actuatable by fluid forces within the cryogen space. A second fluid passage through the partition comprises a restricted flow area that is dimensioned to have a cross-sectional flow area that is smaller than that of a fill conduit such that there is a detectable increase in back-pressure when the main storage space is filled with liquefied gas.

Abstract: A method for supplying a refined liquefied gas, in which prior to the supply of a liquefied gas stored in a container, the liquefied gas is refined by (1) determining the concentrations of impurities in the gas phase, then estimating the concentration of each impurity in the liquid phase from the ratio between the liquid-phase concentration and the gas-phase concentration of the impurity (gas-liquid equilibrium constant (Kn)), and assuming the amount of the gas to be discharged from the gas phase part within the refinement tank to refine the liquefied gas, (2) discharging the gas from the gas phase part to refine the liquefied gas constituting the liquid phase, (3) sampling the gas phase and ascertaining the quality of the refined liquefied gas, and (4) supplying the refined liquefied gas to a receiver from the refinement tank.

Abstract: LNG from a carrier is unloaded to an LNG storage tank in configurations and methods in which expansion of compressed and condensed boil-off vapors from the LNG storage tank provide refrigeration to subcool the LNG that is being unloaded. Most advantageously, such configuration and methods reduce the amount of boil-off vapors and eliminate the need for a vapor return line and associated compressor.

Abstract: A liquefied gas supply system and method can supply the liquefied gas in a plurality of liquefied gas containers uniformly to supply huge amount of gas constantly. A liquefied gas supply system comprises a plurality of liquefied gas containers 1, a detector 2 installed in each of the containers 1 to detect a volume of liquefied gas contained in each of the containers 1, a heating device 3 installed on each of the container 1 and a control device 7 to process information obtained by each of the detectors 2 and control each of the heating devices 3. The control device 7 controls each of the heating devices 3 based on a value obtained by overall processing of the information obtained by each of the detectors 2.

Abstract: A nuclear magnetic resonance (NMR) apparatus (10) comprises a superconducting main field magnet coil system (14) which generates a homogeneous magnetic field of at least 3T, and a gradient coil system (15) which generates a gradient strength of at least 10 mTm?1, with a slew rate of at least 100 Tm?1s?1, wherein the main field magnet coil system (14) is arranged in a cryostat (12) with liquid helium and a refrigerator (16) in the form of a pulse tube cooler or a Gifford-McMahon cooler, and wherein an evaporation line (17a, 27a, 37a) is provided for helium that might evaporate from the cryostat. In all states of operation of the NMR apparatus (10) without gradient switching, the refrigerator provides a cooling capacity which is at least 0.

Abstract: A gas-flow cryostat adapted for dynamic temperature regulation using a fluid level sensor; the cryostat further including one or more heaters coupled to various components of the cryostat. As fluid evaporates from a liquid coolant evaporation reservoir within the cryostat, the fluid level sensor and a feedback control unit are adapted to monitor and dynamically control the level of evaporating coolant by regulating the heaters. Accordingly, the cryostat is adapted to dynamically control temperature about a specimen region within the cryostat. The cryostat can be used in various applications, including analytical laboratory equipment for measuring various physical properties of samples. Temperature sensors are further incorporated for added control and optimization of the cryostat.

Abstract: The present invention relates to a gas supply device having a compact configuration that enables prevention of vaporized gas by requisite minimum heating means from being liquefied again and an installation area to be considerably reduced. The gas supply device is provided with: a tank configured to retain material liquid; and a mass flow controller that is connected to an inside of the tank through a first valve unit, and controls a flow rate of gas resulting from vaporizing the material liquid, in which inside an outer wall of the tank, an internal flow path is formed, and the internal flow path is provided with a generated gas lead-out line provided with: a first valve flow-in flow path connecting the inside of the tank and a first inlet port; and a first valve flow-out flow path connecting a first outlet port and an introduction port of the mass flow controller .

Abstract: A service station, in particular a hydrogen service station for filling a motor vehicle with a gaseous and/or a liquid medium, in particular with gaseous or liquid hydrogen, is disclosed. The station includes a) a reservoir for storing a liquid medium, b) a liquid medium dispensing unit which is supplied with the liquid medium from the reservoir, c) a compressor, an evaporator, a heating system, and an intermediate reservoir for intermediate storage of a compressed gaseous medium, d) a gaseous medium dispensing unit mounted downstream of the intermediate reservoir, e) a fuel cell which is supplied by the gaseous medium coming from the reservoir and/or the intermediate reservoir and supplies power to the compressor, and f) a control unit which is powered by the fuel cell and used for controlling the compressor, the gaseous medium dispensing unit and/or the liquid medium dispensing unit.

Abstract: A method and apparatus for the controlled storage of liquefied gases such as liquefied natural gas in an enclosed insulated container, in which part of the liquid is withdrawn and fed to an external refrigeration unit for subcooling and the subcooled liquid is reintroduced into the container via one or more valve-controlled headers under the control of a control system operated in response to pressure and temperature signals from within the container, wherein the level of subcooling is matched to the heat inleak into the container and most or all of the subcooled liquid is reintroduced directly into the stored liquid so as to maintain stable conditions in the stored liquid and to minimise evaporation thereof.

Abstract: A freezer that uses liquid cryogen as a refrigerant includes an inner vessel defining a storage chamber and an outer jacket generally surrounding the inner vessel so that an insulation space is defined there between. A heat exchanger is positioned in a top portion of the storage chamber and has an inlet in communication with a supply of the liquid cryogen refrigerant so that the liquid cryogen refrigerant selectively flows through the heat exchanger to cool the storage chamber while being vaporized. A purge line is in communication with the outlet of the heat exchanger and includes a purge outlet positioned over the exterior of the heat exchanger. A purge valve is positioned within the purge line so that the vaporized liquid cryogen from the heat exchanger is selectively directed to the exterior of the heat exchanger to reduce ice formation on the heat exchanger.

Abstract: The method of vaporizing LNG consists in using previously dehumidified ambient air as a direct heat exchange fluid in a first air heat exchanger (5) for heating said LNG to a certain temperature. The dehumidification of the ambient air consists in reducing the temperature of the air in a second air heat exchanger (4) by direct heat exchange with said LNG previously heated in said first heat exchanger (5) at least to said certain temperature, said certain temperature lying approximately in the range ?10° C. to ?25° C.

Abstract: A portable fluid delivering system is provided. The system comprises a container, a heat source, a flow rate regulating device and a delivery tube. The container has a containing space for a fluid to be delivered, in a liquid state at room temperature. The heat source provides an elevated vapor pressure in the containing space over the fluid to be delivered, whereby the fluid to be delivered is driven at a desirable rate along the delivery tube.

Abstract: A LNG storage and regasification plant includes a reliquefaction unit in which boil-off vapors from the storage tanks are re liquefied and recycled back to the LNG storage tanks for tank pressure and Wobbe index control. Preferably, LNG cold is used for reliquefaction and operational flexibility is achieved by feeding a portion of the pressurized boil-off gas to a fuel gas header and/or to be recondensed by the sendout LNG.

Abstract: A quench line and exit plenum configuration for a mobile MRI system housed in a transportable trailer includes an exit plenum with deflector plates that direct the quench flow of cold gases upward and away from surrounding objects. In addition, the plenum also includes dual vents to facilitate optimum gas flow and water drainage. The deflector plates are configured to utilize the Venturi effect to create an auxiliary flow of the ambient air to help deflect the flow of cold gases away from nearby pedestrians, when the magnet is quenching, and to enable service personnel to fill the magnet safely while in the vicinity of the exit plenum.

Abstract: A pre-assembled, pre-tested quench path outlet assembly for providing a cryogen egress path from a cryogen vessel. A quench valve (26) is mounted within a flange (28). A cryogen egress tube (32) is sealed in leak-tight manner to the flange, to define a cryogen egress path (40) extending through the cryogen egress tube, the flange and the quench valve. The cryogen egress path is closed by a burst disc (34). In use, the pre-assembled, pre-tested quench path outlet assembly is mounted onto the cryogen vessel such that thermal stratification of gas within the cryogen vessel under normal conditions causes a lower end of the cryogen egress tube to be at a temperature below the freezing points of common air components.

Abstract: The present invention describes methods and systems of oxygen transfill that includes the step of delivering a quantity of liquid oxygen to an evaporation chamber in a liquid oxygen evaporation device. Next, at least a portion of the liquid oxygen in the evaporation chamber is evaporated and a quantity of gaseous oxygen is maintained at a predetermined pressure level in the evaporation chamber. The method includes filling a portable compressed oxygen device with at least a portion of the gaseous oxygen.

Abstract: An operating method is provided for a cryo-compressed tank for supplying cryogenic hydrogen to a consumer of a motor vehicle under supercritical pressure at 13 bar or more. In order to compensate for pressure loss resulting from hydrogen removal, the removed hydrogen that has been heated in a heat exchanger is conveyed to a heat exchanger, provided in the cryo-compressed tank, by way of a tank pressure regulating valve and a branch line, which branches off of a supply line leading to the consumer. After flowing through the heat exchanger, it is introduced into the supply line downstream of the branching off of the branch line. Over a period of time that significantly exceeds the cycle times of a conventional frequency valve, either the removed amount of hydrogen is guided without limitation into the heat exchanger, provided in the cryo-compressed tank, the tank pressure regulating valve being completely open, or no return of the heated hydrogen into the heat exchanger occurs at all.

Abstract: An apparatus for storing gases such as hydrogen gas at cryogenic temperatures. The hydrogen gas is stored in a storage vessel at cryogenic temperatures and those cryogenic temperatures are sustained by a heat exchanger apparatus which provides nearly uniform distribution of a volatile liquid throughout the hydrogen gas being stored.

Abstract: A self-contained unit which is automated for safety and efficiency recovers emissions present as a result of loading volatile organic compositions at marine or land based vessels or terminals. The unit is enclosed for protection of its components from wind, weather and the saltwater marine environment, while including venting for protection against possible vapor build-up. The unit also includes required support services and materials, and also includes structure for protection against transfer of explosion back into the cargo vessel or terminal.

Abstract: A liquid hydrogen storage tank is provided with a boil-off release pressure above the critical pressure. The super critical pressure hydrogen storage tank has less hydrogen losses than a conventional tank even when used in vehicular applications and can be operated so as to provide zero hydrogen loss with reduced mandatory driving distances.

Abstract: An improved method and apparatus for rapidly cooling prepared food uses a novel combination of cold fluid recirculation and vibration to rapidly cool prepared food in a manner that is cost-effective and easy to practice. One embodiment of an improved rapid food chiller includes a tank for holding ice water or another cooling fluid, baskets for holding standard restaurant pans containing prepared food, a pump for circulating the cooling fluid around the outside of the restaurant pans, and a vibrator for vibrating the cooling fluid and the prepared food.

Abstract: In an apparatus and method for transporting cryogenically cooled goods or equipment, a cryostat containing the cryogenically cooled goods or equipment and partially filled with liquid cryogen is provided with a cryogenic refrigerator for active cooling; and auxiliary equipment sufficient to maintain the cryogenic refrigerator in operation, are all mounted on a transportable carrier such that the transportable carrier may be transported with the cryogenic refrigerator in operation without connection of any of the cryostat, refrigerator and auxiliary equipment to any supplies located off of the transportable carrier.

Abstract: A system for delivering vapor phase fluid at an elevated pressure from a transport vessel containing liquefied or two-phase fluid is provided. The system includes: (a) a transport vessel positioned in a substantially horizontal position; (b) one or more energy delivery devices disposed on the lower portion of the transport vessel wherein the energy delivery devices include a heating means and a thermally conductive non-adhesive layer disposed therebetween to the gaps and provide substantially uniform energy to the transport vessel.

Abstract: The invention relates to a re-configured valve design to accommodate a high volume of product in the delivery system and the dispensation of product upon the application of a predetermined vacuum condition on the downstream side of the valve.

Abstract: Disclosed is an apparatus for containing LNG. The apparatus includes an LNG tank containing liquid phase LNG and boil-off gas of LNG, and an circulating device. The circulating device includes an intake port and a discharge port. The circulating device further includes an flowing pathway from the intake port to the discharge port that does not include a forced LNG liquefying device. The intake port is located in an upper portion of the LNG tank, and the discharge port is located in a lower portion of the LNG tank substantially lower than the intake port. The circulating device is configured to suction, through the intake port, boil-off gas from the upper portion of the LNG tank and to discharge boil-off gas, through the discharge port, to the lower portion of the LNG tank.

Abstract: A fuel gas supply system of a vessel, such as an LNG carrier, is provided for supplying fuel gas to a high-pressure gas injection engine of an LNG carrier, wherein LNG is extracted from an LNG storage tank of the LNG carrier, compressed at a high pressure, gasified, and then supplied to the high-pressure gas injection engine. In one embodiment, the system includes a boil-off gas reliquefaction apparatus for reliquefying boil-off gas generated in the LNG tank.