High-voltage two-phase buffer tank device

Abstract

The present invention relates to a high-pressure two-phase buffer tank device (7) for distributing fuel gas from at least one liquefied gas source (2) to at least one gas consuming member (3). The device comprises a container (27) and a closing member (28). The container (27) comprises a structural wall that is insulated and airtight, and an inner layer (34) that has a lower specific heat capacity than the structural wall and is sealed to the liquefied gas.

Description

Technical Field

[0001] The present invention relates to the field of cryogenic engineering. Background Art

[0002] Cryogenic engineering provides solutions for marine transportation, railway transportation, road transportation, and stationary gas storage.

[0003] In the aviation field, high-octane gasoline engines have been used since the dawn of the industry. After 1945, with the development of jet engines and turbines, kerosene, which has a larger molecular weight, higher energy density, higher efficiency and lower flammability than gasoline, has come into use. These fuels are usually stored in tanks arranged in the main wings, at the junction between the fuselage and the main wings, or in the tail section.

[0004] Driven by the trend of reducing carbon dioxide emissions, engines with lower fuel consumption have been developed. However, as several technologies mature, particularly as exemplified by the tip speed of turbine blades, the effect of reducing carbon dioxide emissions is gradually diminishing. There is an increasing demand for the introduction of drastic changes.

[0005] Under such circumstances, the development of gas-fueled aircraft is progressing. Combustion of gases with short or no carbon chains together with oxygen as required produces little or no pollution. On the other hand, hydrogen (H2), oxygen (O2) or C1 or C2 gases are difficult to store and prone to leakage due to their small molecular size.

[0006] On the ground, storage of hydrogen, methane, ethane, ethylene, acetylene or oxygen is generally carried out by pressure vessels, which are too heavy, too bulky, and have excessively high potential pressure energy for installation on aircraft, or by welded and / or bonded cryogenic tanks. Cryogenic storage is limited to a limited period proportional to the storage volume.

[0007] Furthermore, gases stored in liquid form cannot be used directly in internal combustion engines, external combustion engines, or fuel cells. Final consumption requires gas within the temperature and pressure range specified by the manufacturer of the consuming device.

[0008] Cryogenic engineering and aeronautical engineering have vastly different requirements, making it difficult to reconcile the two.

[0009] In aircraft, it is necessary to adjust the gas for consumption while on board. WO2022263307 discloses a fuel circuit including a buffer tank and a plurality of compression modules supplying the buffer tank, each compression module comprising a fixed-volume element tank, a heating means for raising the temperature of the fuel in the element tank under isovolumetric conditions, an inlet valve connecting the element tank to the upstream part of the fuel circuit, an outlet valve connecting the element tank to the buffer tank, and a degassing valve connecting the element tank to the cryogenic tank via a return circuit through which the gas flow passes.

[0010] The present invention aims to improve this situation. [Overview of the project]

[0011] The present invention provides a high-pressure two-phase buffer tank device.

[0012] The present invention provides a high-pressure two-phase buffer tank device for distributing fuel gas from at least one liquefied gas source to at least one gas-consuming component. The device comprises a container and a closing member. The container comprises a structural wall that is insulated and airtight, and an inner layer having a lower specific heat capacity than the structural wall and sealed to the liquefied gas. The inner layer having a low specific heat capacity or low thermal inertia makes it possible to reduce gasification during the buffer tank filling process. The inner layer reduces heat conduction. After filling, the buffer tank is closed again. Subsequently, gasification is required so that the fuel gas can be supplied downstream. Gasification is undesirable during the short filling stage but desirable in subsequent stages. The gas can be used as fuel in an internal combustion engine or as fuel in a fuel cell. After gasification, the term "fuel gas" is used below.

[0013] In one embodiment, the structural wall comprises a structural and thermally insulating first layer made of a carbon fiber-based composite material, and at least one airtight second layer made of polymer. The inner layer has a specific heat capacity lower than that of the first layer and lower than that of the second layer. The first layer is high-strength and lightweight.

[0014] In one embodiment, the structural wall comprises a third layer having higher thermal insulation properties than the first and second layers. In this case, the inner layer has a lower specific heat capacity than the third layer. The second and third layers have good thermal insulation properties.

[0015] In one embodiment, the inner layer is made of a metallic material, particularly selected from aluminum, stainless steel, titanium, Inconel, and ferronickel with a nickel content of 30-40%, and has a thickness of 10-300 microns. The inner layer has a low heat capacity. Therefore, the inner layer supplies almost no energy to the liquefied gas during the filling process, when it is at a higher temperature than the liquefied gas.

[0016] In one embodiment, the inner layer is bonded to the structural wall. The inner layer may have a low thickness. The inner layer may have a thickness of 10 to 300 microns. The inner layer may be made of a lightweight and conductive material such as aluminum.

[0017] In one embodiment, the inner layer is not bound to the structural wall and is gas permeable. Alternatively, the inner layer is not bound to the structural wall and has at least one gap at the top. The inner layer is at least largely separated from the contents of the container and defines the surrounding chamber filled with fuel gas, and functions as temporary insulation for filling.

[0018] In one embodiment, the inner layer is not bound to the structural wall and is airtight, forming a chamber that communicates with the outside together with the third layer, and this chamber is filled with insulating gas. The inner layer defines the surrounding chamber, which is filled with gas separated from the contents of the container, and functions as an insulating material.

[0019] In one embodiment, the inner layer has lower thermal insulation properties than each of the first and second layers, and, if necessary, lower thermal insulation properties than the third layer and lower heat capacity than the third layer. Desirable characteristics of the inner layer are low mass and low heat capacity.

[0020] In one embodiment, the layers of the structural wall are bonded to each other. The bonded layers of the wall provide high rigidity.

[0021] In one embodiment, the closing member comprises a plug and at least one passage for filling with liquefied gas and extracting fuel gas. Inspection of the device is facilitated.

[0022] In one embodiment, A gas distribution assembly between at least one liquefied gas source and at least one gas consumption member is, At the outlet of each liquefied gas source, there is at least one first valve that is controlled to be on or off, a cryogenic distributor connected to each of the first valves, to which liquid is supplied; a plurality of second valves connected in parallel to the cryogenic distributor and controlled to be on or off; a plurality of buffer tank devices to which liquid is supplied by each of the second valves and which supply gas; a third control valve provided at an outlet of each of the buffer tank devices for supplying gas; a regulator provided at an outlet of the third control valve; a manifold supplied by the regulator and configured to supply gas to the at least one gas consuming member comprising: Fuel gas distribution is provided from liquefied gas stored at low temperature and low pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Further features and advantages of the present invention will become apparent upon consideration of the following detailed description and the accompanying drawings, wherein: [Figure 1] FIG. 1 is a schematic perspective view of a distribution assembly according to an aspect of the present invention. [Figure 2] FIG. 2 is a schematic axial cross-sectional view of a distribution assembly according to an aspect of the present invention. [Figure 3] FIG. 3 is a diagram showing details of the above figure. [Figure 4] FIG. 4 is a diagram showing a modification of the above figure. [Figure 5] FIG. 5 is a schematic axial cross-sectional view of a device according to an aspect of the present invention. [Figure 6] FIG. 6 is a schematic axial cross-sectional view of a device according to an aspect of the present invention. [Figure 7] FIG. 7 is a schematic axial cross-sectional view of a device according to an aspect of the present invention in a cooling step. [Figure 8] FIG. 8 is a schematic axial cross-sectional view of a device according to an aspect of the present invention in a filling step. [Figure 9] FIG. 9 is a schematic axial cross-sectional view of a device according to an aspect of the present invention in a pressure increasing step. [Figure 10] This figure schematically shows an apparatus according to one aspect of the present invention in an axial cross-section during the extraction process. [Figure 11] This figure schematically shows an apparatus according to one aspect of the present invention in an axial cross-section during the atmospheric pressure return process. [Modes for carrying out the invention]

[0024] The attached drawings are not only used to supplement the present invention, but may also contribute to the definition of the present invention as needed.

[0025] The gas distribution assembly is designed to be fixed in place or vehicle-mounted, particularly for use in aircraft, i.e., airplanes, drones, helicopters, etc. The assembly is supplied with a liquid and a gas at a selected pressure. That is, the fuel or oxidizer is stored at cryogenic temperatures in a liquid state within a cryogenic tank. According to one embodiment, gaseous hydrogen at 0°C and 1 atmosphere has a density approximately 800 times lower and therefore a volume approximately 800 times larger than liquid hydrogen at -253°C. The cryogenic tank cannot withstand high pressure, especially pressures exceeding 10 bar.

[0026] The gases to be stored are selected from hydrogen, methane, ethane, ethylene, acetylene, and oxygen.

[0027] The applicant recognized the need to distribute gas from aviation cryogenic tanks, whether the aviation cryogenic tanks are integrated into the aircraft's structure, installed inside the aircraft, or mounted on the aircraft.

[0028] From another perspective, aircraft currently, under ETOPS certification, are subject to regulations regarding the maximum distance from an alternative airport, expressed as flight time. This distance depends on the type of aircraft.

[0029] To ensure a high level of safety and user awareness, the applicant recognized the need to be able to continue flight even if it becomes necessary to release the contents into the atmosphere due to damage to the cryogenic tank.

[0030] The applicant has found that the buffer tank must be insulated from the outside, have a very low specific heat capacity for the liquefied gas flowing in when the buffer tank is filled, be low in mass and compact, withstand temperatures from -253°C to +50°C, withstand temperature fluctuations, withstand mechanical stresses such as acceleration and vibration in particular, and withstand internal fuel gas pressures exceeding 500 bar or reaching 700 bar. The structure of the buffer tank requires a configuration with extremely high robustness.

[0031] The filling process is carried out using liquefied gas. The pressure in the buffer tank is lower than the pressure of the source supplying the liquefied gas, due to pumping or flow caused by the pressure difference. The buffer tank is located near room temperature, within a range of approximately ±10°C or ±20°C, with room temperature ranging from -56°C at altitude to +50°C under high-temperature conditions on the ground. However, the enthalpy of evaporation of the liquefied gas is low. When liquefied gas is introduced into a buffer tank with a temperature 50-300°C higher, gasification occurs very rapidly from the initial stage. The pressure in the buffer tank rises sharply. As a result, filling stops.

[0032] The need arose for easier, more reproducible, and more reliable filling. For this purpose, buffer tank devices and gas distribution assemblies were designed.

[0033] In the embodiment shown in Figure 1, the gas distribution assembly 1 is supplied by a liquefied gas source 2 and supplies gas to one or more gas-consuming components 3. Here, two gas-consuming components 3 are shown, for example, two propulsion units, one power generator, or one air heater. A flow meter 22 is provided at the outlet of each liquefied gas source 2. The gas distribution assembly 1 can be mounted on an aircraft.

[0034] The liquefied gas source 2 in this case includes two cryogenic tanks arranged in parallel. Each cryogenic tank is provided with an outlet line 4. The terms upstream and downstream refer to the direction of fluid flow (i.e., liquid and subsequent gas) in normal operation.

[0035] Each cryogenic tank is insulated to contain liquefied gases, such as liquid hydrogen at -253°C. Each cryogenic tank can withstand a maximum operating pressure of approximately 6 to 10 bar.

[0036] The gas distribution assembly 1 includes a first valve 11 for each cryogenic tank. The first valve 11 is located on the outlet line 4. The first valve 11 is controlled in an open position and a closed position. The intermediate positions of the first valve 11 are dynamic; that is, the first valve 11 is operating as it passes through these intermediate positions. In other words, the first valve 11 is either on or off. The first valve 11 may be located immediately downstream of the flow meter 22. Optionally, the flow meter 22 may be located downstream of the first valve 11.

[0037] The first valve 11 is in communication with a low-temperature distributor 5. The low-temperature distributor 5 may have a common line 6 connected to the outlet of the first valve 11. This distributor is for low-temperature use in the sense that it handles liquefied gas.

[0038] The low-temperature distributor 5 has multiple outlets, in this case three. Each of these outlets is provided with a second valve 12. The second valve 12 is controlled in an open position and a closed position. The intermediate position of the second valve 12 is dynamic; that is, the second valve 12 is operating as it passes through these intermediate positions. In other words, the second valve 12 is either on or off. In this case, there are three second valves 12.

[0039] Unlike cryogenic valves used in space applications, which do not need to be closed again once used, the first valve 11 and the second valve 12 are reclosable, for example, solenoid valves.

[0040] A buffer tank device 7 is provided downstream of each second valve 12. In this embodiment, three buffer tank devices 7 are provided. Each buffer tank device 7 also functions as a gasifier. Isolation is not required. Each buffer tank device 7 receives liquid and supplies gas downstream. In each buffer tank device 7, a pressurization or gasification process takes place between filling and discharging. Each buffer tank device 7 can withstand a maximum operating pressure of approximately 300 to 1000 bar. Each buffer tank device 7 is designed to operate in a temperature range of -253°C to +60°C. The buffer tank device 7 is in a two-phase state during some operating stages and in a single-phase gas state during other operating stages. Each buffer tank device 7 may include an externally located heating element 8 in the configuration shown in Figure 1.

[0041] Downstream of each buffer tank device 7 is a third valve 13 for supplying gas, and further downstream of the third valve 13 is a regulator 9. The regulator 9 limits the pressure to supply gas at the consumption pressure set by the manufacturer of the gas consumption component 3. The regulator 9 operates when the pressure in the buffer tank device 7 is higher than the consumption pressure, and does not operate otherwise. The consumption pressure is lower than the maximum pressure of the buffer tank device 7. The consumption pressure is independent of the maximum pressure of the cryogenic tank. The third valve 13 is either on or off.

[0042] A fourth control valve 14 may be provided downstream of each regulator 9. The fourth valve 14 is either on or off.

[0043] The fourth valve 14 or, depending on the selected configuration, the regulator 9 is connected to the manifold 10. The manifold 10 may include lines connecting to the outlets of the fourth valve 14 or the regulator 9. The gas passes through the manifold 10. The manifold 10 is connected downstream to a supply line 23, which supplies gas to the gas consuming members 3. Generally, one supply line 23 is provided for each gas consuming member 3. Each supply line 23 may be provided with a controllable supply valve 24. The supply valve 24 has a variable flow rate.

[0044] The gas distribution assembly 1 may include at least one compressor 20 connected to the manifold 10. Generally, two compressors 20 are provided in parallel for redundancy. The compressors 20 are electric. The compressors 20 may be provided with a controllable upstream valve. The compressors 20 distribute gas to the manifold 10. In particular, when there is only one gas consuming member 3, the manifold 10 consists of lines.

[0045] Downstream of each buffer tank device 7, a fifth valve 15 is provided for supplying gas, and further downstream of the fifth valve 15, a second manifold is provided. The second manifold is connected to the compressor 20. The fifth valve 15 isolates the buffer tank device 7 from the compressor 20. The fifth valve 15 is controlled; it is either on or off.

[0046] The compressor 20 increases the pressure and supplies gas at the consumption pressure set by the manufacturer of the gas consumption component 3. The consumption pressure is lower than the maximum pressure in the buffer tank device 7. When the pressure in the buffer tank device 7 is lower than the consumption pressure, the compressor 20 enables the extraction of gas from the buffer tank device 7 and supplying it to the manifold 10 and the gas consumption component 3. More complete draining of the buffer tank device 7 makes it possible to extend the cruising range obtained by the gas contained in the buffer tank device 7 or to reduce the volume of the buffer tank device 7.

[0047] By completely draining the buffer tank device 7 and lowering the pressure inside the buffer tank device 7 to a value lower than the pressure in any of the cryogenic tanks, it becomes possible to transfer liquid from the cryogenic tanks to the buffer tank device 7 by pressure difference during refilling after draining. In other words, the liquid in the cryogenic tanks flows into the buffer tank device 7 until pressure equilibrium is reached. As a result, a cryogenic pump is not required, and weight and energy consumption are reduced.

[0048] The gas distribution assembly 1 provides combinations of individual states for each cryogenic tank, each buffer tank device 7, and each gas consuming member 3. Multiple gas consuming members 3 can operate simultaneously. In normal mode, one cryogenic tank is discharged, and the other cryogenic tanks are inoperable and therefore closed. However, a special mode may be provided in which multiple cryogenic tanks are discharged simultaneously, for example, to reduce the pressure in multiple cryogenic tanks. The buffer tank device 7 has a filling mode, a gasification mode, a gas storage mode, and a discharge mode.

[0049] When one of the cryogenic tanks is being discharged, the corresponding first valve 11 is open, and the other first valve 11 is closed. When gas is being supplied to one of the gas consumption members 3, the corresponding supply valve 24 is open.

[0050] When one of the buffer tank devices 7 is in filling mode, the second valve 12 connected to that buffer tank device 7 is open, and at least one first valve 11 is open. The other second valve 12 is closed, except when both buffer tank devices 7 are filling simultaneously. The third valve 13 connected to that buffer tank device 7 is closed. The fifth valve 15 connected to that buffer tank device 7 is closed.

[0051] When one of the buffer tank devices 7 is in gasification mode, the second valve 12, the third valve 13, and the fifth valve 15 connected to the buffer tank device 7 are closed. The gasification mode is short-lived, especially when the ambient temperature is high and / or when the buffer tank device 7 is heated.

[0052] When one of the buffer tank devices 7 is in discharge mode, the second valve 12 connected to that buffer tank device 7 is closed. In the first stage of discharge, the pressure inside the buffer tank device 7 is higher than the consumption pressure. The third valve 13 connected to that buffer tank device 7 is open, the corresponding fourth valve 14 is open, and the fifth valve 15 connected to that buffer tank device 7 is closed. The gas is depressurized in the regulator 9 and supplied to the manifold 10 at the consumption pressure. The gas is then consumed by the gas consumption member 3.

[0053] At a given point in time, of the three buffer tank devices 7, one is in filling mode, another is in storage mode after gasification mode, and the remaining one is in discharge mode. Because the duration of each mode differs, it is possible that two buffer tank devices 7 are simultaneously in filling mode while the remaining one is in discharge mode, or vice versa. It is also possible that two buffer tank devices 7 are in storage mode while the remaining one is in discharge mode, or vice versa.

[0054] In one embodiment, a flow meter 22 is provided at the outlet of each liquefied gas source 2. The flow meter 22 allows for the determination of the amount of liquid supplied to a specific buffer tank device 7 with sufficient accuracy.

[0055] In one embodiment, the gas distribution assembly 1 includes a control unit 25, which receives external commands from, for example, a gas consumption member 3 or a central control unit, and liquid flow rate data from a flow meter 22. The control unit 25 generates and transmits commands to the first valve 11, the second valve 12, the third valve 13, the fourth valve 14, the fifth valve 15, and the supply valve 24. These commands are either "open" or "closed". The control unit 25 manages combinations of the individual states.

[0056] Alternatively, the first valve 11 may be replaced by at least one multi-way valve having multiple inlets and one outlet. In this case, it is useful to provide a multi-way valve with a mixing position, particularly one with at least one position capable of simultaneously exhausting two or more liquefied gas sources 2, in order to reduce the pressure and prevent leakage into the atmosphere.

[0057] Alternatively, the second valve 12 may be replaced by at least one multi-way valve having one inlet and multiple outlets, i.e., one outlet for each buffer tank device 7. The multi-way valve constitutes a distributor.

[0058] Alternatively, regulator 9 may be replaced by a single regulator 9, and the third valve 13 may be connected to the single regulator 9. In this case, the third valve 13 may be replaced by at least one multiway valve having multiple inlets and one outlet and connected to the regulator. In this case, the fourth valve 14 may be replaced by a single fourth valve 14, and the fourth valve 14 may be uncontrolled.

[0059] Alternatively, the fifth valve 15 may be replaced by at least one multi-way valve. This multi-way valve has one inlet for each buffer tank device 7 and one outlet leading to a compressor 20 or a plurality of compressors 20. The multi-way valve constitutes the manifold 10.

[0060] The buffer tank device 7 is shown in more detail in Figures 2 to 11.

[0061] The buffer tank device 7 is two-phase in that it is designed to contain a substantially liquid content at low temperatures and a gaseous content under high pressure. The substantially liquid content consists of 80-90% liquid and a gaseous headspace. The gaseous content can reach high pressures of several hundred bar. The buffer tank device 7 can be mounted on an aircraft, for example, internally mounted in the fuselage or in the wings if the wings are thick enough, or externally mounted under the wings.

[0062] In the embodiments shown in Figures 2 and 3, the buffer tank device 7 comprises a container 27 and a closing member 28. The container 27 is rigid. The container 27 is heat insulating. The container 27 is airtight. The container 27 can withstand low temperatures inside the container 27. The container 27 can withstand rapid temperature changes. In the illustrated embodiments, the container 27 has a multilayer structure.

[0063] The container 27 is provided with an opening 29. The closing member 28 is positioned inside the opening 29, ensuring that the contents are retained while enabling the contents to be filled into and discharged into the downstream member.

[0064] The container 27 comprises a wall and an inner layer 34. The wall is structural, has thermal insulation properties, and is airtight. The wall comprises a first layer 31, a second layer 32, and a third layer 33, extending from the outside to the inside (see Figure 3). Alternatively, the wall comprises a first layer 31 and a second layer 32, extending from the outside to the inside (see Figure 4).

[0065] The first layer 31 is structural in that it provides the container 27 with shape, rigidity, and external mechanical connection to the container support. The first layer 31 may have thermal insulation properties. The inner layer 34 has a specific heat capacity lower than that of the third layer 33. The first layer 31, the second layer 32, and the third layer 33 form an integrated structure with mechanical, thermal, and sealing functions. The inner layer 34 is located inside.

[0066] The container 27 has a rotationally symmetric shape and comprises a cylindrical central portion, a hemispherical arc-shaped bottom portion, and a hemispherical arc-shaped top portion. The top portion is covered by a neck 30 that defines a bore. The neck 30 may have a thickness greater than the thickness of the central portion and the bottom portion in order to absorb the mechanical force transmitted from the closing member 28. The neck 30 is formed by at least a first layer 31, optionally a second layer 32, and optionally a third layer 33.

[0067] The first layer 31 is made of a composite material. The first layer 31 includes, for example, carbon or aramid fibers and a matrix. The first layer 31 can withstand low temperatures and rapid temperature changes. The first layer 31 has a first thickness. The first thickness is set according to the volume and shape of the container, as well as the external and internal pressures. The first layer 31 is continuous except for the opening 29. In this case, the first layer 31 extends over the entire height of the container 27.

[0068] The second layer 32 is airtight. The second layer 32 provides sealing of the container 27, especially against small molecules such as hydrogen. The sealing of the second layer 32 is 10 for helium. -10 Pa·m 3 It is less than / s. The second layer 32 has a second thickness. The second thickness is less than the first thickness. The second layer 32 is made of polymer. The second thickness can be 0.1 to 10 mm. The first layer 31 and the second layer 32 are preferably bonded to each other. The second layer 32 is continuous except for the opening 29. In this case, the second layer 32 extends over the entire height of the container 27 except for the neck 30.

[0069] The third layer 33 has higher thermal insulation properties than the first and second layers. The third layer 33 provides thermal insulation to the container 27. The third layer 33 has a thermal insulation rating of 100 mW·m -1 ·K -1 It has a thermal conductivity of less than 1. The third layer 33 may be made of a polymer, for example, fiber-reinforced PU foam. Alternatively, the third layer 33 may be made of mineral wool. The third layer 33 has a third thickness. The third thickness is greater than the first thickness. The third thickness can be 1 to 100 mm. The second layer 32 and the third layer 33 are preferably bonded to each other. The third layer 33 is continuous except for the opening 29. In this case, the third layer 33 extends over the entire height of the container 27 except for the neck 30.

[0070] The inner layer 34 has a lower specific heat capacity than each of the first, second, and third layers. The inner layer 34 is sealed against liquefied gas. Airtightness is not required. The inner layer 34 reduces gas generation during filling. The inner layer 34 has lower thermal insulation than each of the first, second, and third layers.

[0071] The inner layer 34 is made of a metal, such as aluminum or an aluminum alloy. More generally, the inner layer 34 is a metal. The metal of the inner layer 34 can be selected from aluminum, stainless steel, titanium, Inconel, and ferronickel. In the case of ferronickel, the Ni content is 30-40%. Therefore, a material with low specific heat capacity, resistance to low temperatures, and low surface density is used for the intended application.

[0072] The inner layer 34 has a fourth thickness. This fourth thickness is smaller than the first, second, and third thicknesses. The fourth thickness can be 10 to 300 microns.

[0073] In the embodiment shown in Figure 3, the inner layer 34 is adhered to the wall. The inner layer 34 is formed on the third layer 33, for example, over its entire inner surface. In this case, the inner layer 34 may have a low thickness, particularly 10 to 300 microns.

[0074] In the embodiment shown in Figure 4, the inner layer 34 is not bound to the wall (it can move freely). The inner layer 34 may be permeable to fuel gas. The inner layer 34 may be impermeable to liquids, especially liquefied gases. In this case, the second layer 32 and the inner layer 34 can form a chamber 35. The chamber 35 may have a variable volume. In this case, the inner layer 34 may have a thickness of 0.01 to 1 mm.

[0075] Alternatively, referring to Figure 6, the inner layer 34 may have at least one gap 36 at its top. This gap 36 allows gas to pass between the inner layer 34 and the wall, i.e., into the chamber 35. The gap 36 may be positioned high enough so that it lies within the gas phase headspace at the end of filling and after filling. The gas phase headspace is the portion of the container filled with gas above the liquid phase. The gas phase headspace is minimal at the end of filling and after filling.

[0076] In one embodiment, the container 27 includes an intermediate layer between the third layer 33 and the inner layer 34. This intermediate layer forms an additional insulating material. The intermediate layer comprises a porous material capable of absorbing or adsorbing fuel gas.

[0077] The container 27 is equipped with an insert 37. The insert 37 is sealed. The insert 37 is pressure resistant. The insert 37 is capable of transmitting axial force to the container 27 during high-pressure stages.

[0078] The insert 37 has a generally annular shape. The insert 37 may be made of metal. The insert 37 comprises a lower part 38 that widens downwards and a cylindrical upper part 39. The lower part 38 contacts the inner surface of the top of the container 27. The upper part 39 contacts the bore of the neck 30. The height of the insert 37 is greater than the height of the neck 30 and less than the combined height of the neck 30 and the top of the container 27. The insert 37 is positioned by shape fitting. The insert 37 can be fixed to the neck 30 and the top of the container 27 by adhesive. The insert 37 consists of a single piece. The insert 37 has a gap in the center, which forms an opening 29.

[0079] The opening 29 is axial. The opening 29 has a ribbed or helical peripheral surface. Here, the groove or helix is ​​chevron-shaped in the axial cross-section and is intended to lengthen the heat conduction path. The opening 29 may be covered with a coating of a material different from the material of the insert 37.

[0080] The closing member 28 is sealed. The closing member 28 is pressure resistant. The closing member 28 is removable. The closing member 28 comprises a body that forms a plug. The body comprises a lower part 40 that is housed within the opening 29 and an upper part 41 that protrudes from the opening 29. The upper part 41 contacts the upper surface of the neck 30.

[0081] The closing member 28 is equipped with a filling line 42, which extends through the main body between the outside and inside of the container 27.

[0082] The closing member 28 is equipped with an outlet line 43, which extends through the main body between the outside and inside of the container 27. The outlet line 43 can function as a vent. The outlet line 43 is provided for acquiring gas and supplying it downstream. Within the main body, the outlet line 43 and the filling line 42 are parallel to each other and spaced apart from each other.

[0083] In the embodiment shown in Figure 2, the closing member 28 includes at least one additional passage. An internal heating member 44 is provided within this additional passage. Here, the heating member 44 passes through two additional passages. The heating member 44 is used to accelerate gasification after filling and when the second valve 12 and the third valve 13 are closed, or when at least the second valve 12 is closed. The heating member 44 extends into the upper region of the container, for example, the top of the container and optionally the cylindrical center. The heating member 44 may be provided above the maximum level of liquefied gas. The heating member 44 extends into the gas phase headspace.

[0084] The heating element 44 may be electrically operated, in which case one additional passage is sufficient.

[0085] The heating element 44 may be in a heat exchange relationship with the heat transfer fluid flowing through the piping. The piping in this case is helical in shape. The heating element 44 may comprise a coil of 2 to 5 turns. The heat transfer fluid may be a gas, fuel, or combustion fluid. Two additional passages are provided for the inlet of the high-temperature heat transfer fluid and the outlet of the cooled heat transfer fluid. Alternatively, the inlet and outlet may share one additional passage.

[0086] In the embodiment shown in Figure 1, the heating element 8 is located outside the container 27. In the embodiments shown in Figures 5 and 6, the heating element is either absent or located outside (not shown).

[0087] In the embodiment shown in Figure 5, the aforementioned inner layer 34 is replaced by an outer layer 45. The outer layer 45 forms an insulating jacket surrounding the first layer 31. The outer layer 45 surrounds the upper part 41 of the main body of the closing member 28. The outer layer 45 may be made of a foamed material, for example, EPS. The outer layer 45 may consist of at least two removable parts.

[0088] In the embodiment shown in Figure 6, the inner layer 34 is unbound to the third layer 33 and is airtight. The inner layer 34, together with the wall, forms a chamber 35 that communicates with the outside. This communication with the outside is used for filling and refilling the chamber 35. The chamber 35 is filled with an insulating gas, such as Ar. After filling, the chamber 35 is sealed. Therefore, heating of the liquefied gas during container filling is extremely small. The outer layer 45 improves the heat insulation. The outer layer 45 forms an insulating jacket surrounding the first layer 31. The outer layer 45 surrounds the upper part 41 of the main body of the closing member 28.

[0089] Figures 7 to 11 show the steps for implementing the buffer tank device 7. The buffer tank device 7 is in operation, and the closing member 28 is firmly fixed to the container 27. Starting from an empty tank at ambient temperature, i.e., approximately -56°C to +50°C, the first step, which is a cooling step, is performed. The first step is performed by introducing liquefied gas into the container 27 and degassing it. The liquefied gas may be the same as that used in subsequent steps, or it may be a neutral gas, such as nitrogen. The filling line 42 supplies the liquefied gas while the outlet line 43 is open. The discharge of the liquefied gas causes extremely rapid evaporation and cooling of the inside of the container, starting from the inner layer 34 and then to the third layer 33. The duration of the first step is as short as possible. The present invention makes it possible to shorten the duration of the first step. The pressure at the end of the first step is equal to the ambient pressure, for example, the pressure around an aircraft.

[0090] When the inside of container 27 reaches a selected temperature, a second step begins, which is a filling process with liquefied gas, a precursor of the fuel gas. Filling is carried out by a filling line 42. The extraction line 43 is opened and then closed during the second step, or closed from the start of the second step. A few percent of the volume of container 27 is left as gas phase headspace. The filling line 42 is closed at the end of the second step. The duration of the second step is as short as possible. The short duration of the second step is not as critical as that of the first step. The present invention makes it possible to shorten the duration of the second step. The pressure increases during the second step. The pressure at the end of the second step is less than or equal to the pressure in the cryogenic tank supplying the liquefied gas. The pressure at the end of the second step is 6-10 bar. The use of a cryogenic pump is avoided.

[0091] Once container 27 is filled with the desired amount of liquefied gas, a third step, the pressurization step, is initiated. Pressurization can be assisted by a heating element 44. The heating element 44 is operated for a sufficient amount of time to allow the pressure inside container 27 to reach the minimum pressure required to supply fuel gas downstream. The heating element 44 is inactive during the other steps. During the third step, the take-out line 43 and the filling line 42 are closed. The duration of the third step is as short as possible to bring the buffer tank into operation for fuel gas supply. The short duration of the third step is not as critical as that of the first step. The pressure at the end of the third step is higher than the pressure in the cryogenic container supplying the liquefied gas. The pressure at the end of the third step is 100-700 bar. Pressurization occurs simultaneously with the temperature rise.

[0092] The filling line 42 is closed. Once the pressure increase is achieved, the fourth step, which is the extraction step, is started. The extraction line 43 is opened. The duration of the fourth step is variable according to the downstream fuel gas demand. The pressure at the end of the fourth step depends on whether or not a compressor 20 is present downstream of the buffer tank device 7. If a compressor 20 is provided (see Figure 1), the pressure at the end of the fourth step depends on the characteristics of the compressor 20 and may be lower than the ambient pressure. If a compressor 20 is not present, the pressure at the end of the fourth step depends on the characteristics of the gas consuming component 3. The pressure at the end of the fourth step may be between 1 and 50 bar.

[0093] Once the pressure increase is achieved, the fourth step, which is the extraction step, begins. The extraction line 43 is opened. The filling line 42 is closed. The duration of the fourth step is variable according to the downstream fuel gas demand. The temperature rises gradually according to the extraction flow rate. When the extraction flow rate is high, the temperature rise is slow. When the extraction flow rate is low, the temperature rise is fast. The pressure at the end of the fourth step depends on whether or not a compressor 20 is present downstream of the buffer tank device 7. If a compressor 20 is provided (see Figure 1), the pressure at the end of the fourth step depends on the characteristics of the compressor and may be lower than the ambient pressure.

[0094] If a compressor is not present, the pressure at the end of the fourth step depends on the characteristics of the gas consumption component 3. The pressure at the end of the fourth step can be between 1 and 50 bar. The pressure at the end of the fourth step reaches a level at which the extraction of fuel gas stops.

[0095] Once the pressure at the end of the fourth step is reached, the fifth step, which returns to atmospheric pressure, is initiated. The fifth step is optional. If the pressure at the end of the fourth step is higher than the ambient pressure, degassing is performed by the open outlet line 43. The filling line 42 is closed. The duration of the fifth step is short. The temperature inside the container 27 decreases. The pressure at the end of the fifth step is equal to the ambient pressure, for example, 1013 hPa at ground level or 265 hPa at an altitude of 10000 m. The fifth step is provided if a compressor is not present, or if the compressor 20 does not provide a sufficient flow rate or efficiency to supply the required fuel gas flow rate toward the end of the fourth step.

[0096] After step 5, if container 27 is sufficiently cold, the process proceeds directly to step 2; otherwise, it proceeds to step 1.

[0097] In one embodiment, a high-pressure two-phase aircraft buffer tank device 7 is mounted on an aircraft to distribute fuel gas from at least one liquefied gas source 2 to at least one gas consuming member 3 of the aircraft. The buffer tank device 7 comprises a container 27 and a closing member 28. The container 27 comprises a collection of structural, heat-insulating, and airtight layers, and an inner layer that seals against the liquefied gas and has a specific heat capacity lower than each layer of the collection of layers. The inner layer may be thermally conductive.

[0098] Thanks to the high-pressure two-phase buffer tank system, the inner layer with low specific heat capacity reduces vaporization of liquefied gas and thus pressure rise during filling. Losses are reduced. Filling time is shortened. The probability of incomplete filling is reduced. The ratio of active use time, i.e., the ratio of the fourth process period to the buffer tank cycle period, is improved.

Claims

1. A high-pressure two-phase buffer tank device (7) for distributing fuel gas from at least one liquefied gas source (2) to at least one gas consuming member (3), The above high-pressure two-phase buffer tank device comprises a container (27) and a closing member (28), The above container (27) is A structural wall that is both insulated and airtight, An inner layer (34) that has a lower specific heat capacity than the above-mentioned structural wall and is sealed against liquefied gas and Equipped with, The above structural wall is, A structural and thermally insulating first layer (31) made of a carbon fiber-based composite material, It has airtightness and comprises at least one second layer (32) made of polymer and Equipped with, The inner layer (34) has a specific heat capacity that is lower than that of the first layer (31) and lower than that of the second layer (32). Each layer of the above structural wall is bonded to one another. A high-pressure two-phase buffer tank device characterized by the following features.

2. In the high-voltage two-phase buffer tank device (7) according to claim 1, The above structural wall further comprises a third layer (33) which has higher thermal insulation properties than the first layer (31) and the second layer (32). In this case, the inner layer (34) has a lower specific heat capacity than the third layer (33). A high-pressure two-phase buffer tank device characterized by the following features.

3. In the high-pressure two-phase buffer tank device (7) according to claim 1 or 2, The inner layer (34) is made of a metallic material, and is particularly selected from aluminum, stainless steel, titanium, Inconel, and ferronickel having a nickel content of 30-40%, and has a thickness of 10-300 microns. A high-pressure two-phase buffer tank device characterized by the following features.

4. In the high-pressure two-phase buffer tank device (7) according to any one of claims 1 to 3, The above inner layer (34) is bonded to the above structural wall. A high-pressure two-phase buffer tank device characterized by the following features.

5. In the high-pressure two-phase buffer tank device (7) according to any one of claims 1 to 4, The above inner layer (34) is not bound to the above structural wall. A high-pressure two-phase buffer tank device characterized by the following features.

6. In the high-pressure two-phase buffer tank device (7) according to claim 5, The inner layer (34) described above is gas permeable while being sealed against liquefied gas. A high-pressure two-phase buffer tank device characterized by the following features.

7. In the high-pressure two-phase buffer tank device (7) according to claim 5 or 6, The above inner layer (34) has at least one gap (36) at the top, The gap (36) is positioned high enough to be located within the gas phase headspace at the end of filling and after filling, allowing gas to pass between the inner layer (34) and the structural wall. A high-pressure two-phase buffer tank device characterized by the following features.

8. In the high-pressure two-phase buffer tank device (7) according to any one of claims 1 to 4, The above structural wall further comprises a third layer (33) which has higher thermal insulation properties than the first layer (31) and the second layer (32). The inner layer (34) is not bound to the structural wall and is airtight, and together with the third layer (33) forms a chamber (35) that communicates with the outside. The above chamber (35) is filled with adiabatic gas. A high-pressure two-phase buffer tank device characterized by the following features.

9. In the high-pressure two-phase buffer tank device (7) according to any one of claims 1 to 8, The inner layer (34) has lower thermal insulation properties than the first layer (31) and the second layer (32). A high-pressure two-phase buffer tank device characterized by the following features.

10. In the high-pressure two-phase buffer tank device (7) according to any one of claims 1 to 9, The above structural wall further comprises a third layer (33) which has higher thermal insulation properties than the first layer (31) and the second layer (32). The inner layer (34) has lower thermal insulation properties and a lower specific heat capacity than the third layer (33). A high-pressure two-phase buffer tank device characterized by the following features.

11. In the high-pressure two-phase buffer tank device (7) according to any one of claims 1 to 10, The closing member (28) comprises a plug and at least one passage for filling with liquefied gas and extracting fuel gas. A high-pressure two-phase buffer tank device characterized by the following features.

12. A gas distribution assembly (1) between at least one liquefied gas source (2) and at least one gas consuming member (3), At the outlet of each liquefied gas source (2), there is at least one first valve (11) which is controlled to be on or off, A low-temperature distributor (5) is connected to each of the first valves (11) and supplied with liquid, Multiple second valves (12) that are controlled by being switched on or off are connected in parallel to the above-mentioned low-temperature distributor (5), A plurality of high-pressure two-phase buffer tank devices (7) according to any one of claims 1 to 11, wherein each of the second valves (12) is supplied with liquid and gas, A third control valve (13) for supplying gas is provided at each outlet of the above-mentioned high-pressure two-phase buffer tank device (7), A regulator (9) is provided at the outlet of the third control valve (13) described above, The manifold (10) is supplied by the regulator (9) and supplies gas to the at least one gas consuming member (3) and Equipped with A gas distribution assembly characterized by the following features.

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