Cryopumping-resistant LH2 storage vessel

Abstract

A method and apparatus for storing liquid gas, such as liquid hydrogen, is provided. The liquid gas container includes multiple insulation layers to enable the use of non-vacuum insulation while reducing cryopumping. The inner insulation layer is formed as a closed-cell structure with a material that is sufficiently thick so that the temperature of the outer surface of the inner insulation layer is higher than the boiling point of the gas within the outer insulation layer. The outer insulation layer may have an open-cell structure for the insulating material.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 63 / 522,651, filed June 22, 2023, which is incorporated herein by reference in its entirety.

[0002] Government Rights This invention was made with government support under Grant No. DE-EE0009387 awarded by the Department of Energy. The government has certain rights in this invention.

[0003] FIELD OF THE DISCLOSURE Embodiments of the present disclosure generally relate to cryogenic vessels for storing liquid hydrogen. [Background technology]

[0004] Hydrogen is an alternative energy source to traditional fossil fuels. For example, some modes of transportation, such as automobiles, are powered by hydrogen fuel cells. Hydrogen is also finding other industrial applications, such as the Haber-Bosch process for producing fertilizer. As demand for hydrogen increases, due in part to the development and consumer adoption of more efficient hydrogen-powered vehicles and machines, there is a need to store hydrogen in industrial quantities.

[0005] Hydrogen gas has a low density. To efficiently store industrial quantities of hydrogen gas, it is liquefied. However, liquefied hydrogen gas is very cold, which places stress on its container. For example, the boiling point of liquefied hydrogen gas at one atmosphere of pressure is approximately -253°C (20°K). Therefore, liquid hydrogen is typically stored at conditions close to ambient pressure and a temperature of approximately 20 Kelvin.

[0006] Liquid hydrogen storage requires insulation to reduce heat transfer between the liquid hydrogen and the external environment. Without insulation, the liquid hydrogen would rapidly change phase to gaseous hydrogen (commonly known as evaporation), and the outside of the storage container would be cold enough to liquefy or freeze most components of air, such as nitrogen and oxygen.

[0007] Liquid hydrogen is cold enough to condense and freeze atmospheric gases, such as nitrogen or oxygen gas, in its presence, on the walls of the vessel containing the liquid hydrogen. The condensation and freezing of the atmospheric gases transfers heat to the liquid hydrogen, causing it to evaporate. The evaporated hydrogen gas may have to be vented, resulting in losses. As a result, some liquid hydrogen containment vessels include vacuum insulation to avoid the heat load caused by the condensation or freezing of the atmospheric gases.

[0008] Conventional liquid hydrogen storage vessels consist of a double-walled steel vessel with vacuum insulation. The inner steel vessel wall, which stores the liquid hydrogen, is suspended from the outer steel vessel wall. Insulating material is placed between the two vessel walls under vacuum. In all insulating materials, the evacuation of air prevents convective heat transfer and also prevents heat transfer that would otherwise occur if gas in the insulated space liquefies against the cold inner vessel, thereby reducing the insulation's effectiveness.

[0009] The outer steel vessel wall of a liquid hydrogen storage vessel is limited in size due to the tendency of the steel wall to buckle due to the vacuum load of the vacuum insulation. Therefore, the outer vessel must be designed to withstand the pressure differential created by evacuating the insulated space, which could cause the outer vessel to buckle inward and collapse.

[0010] Vacuum-jacketed insulation is cost-effective for smaller storage vessels, but for very large storage vessels, designing the outer vessel for vacuum can be prohibitively expensive. Rocket fuel tanks are often insulated with a single layer of foam due to weight constraints, but they experience very high evaporation rates, very short storage times measured in hours, adsorption of water vapor and gases that can cause damage to the foam, and ice formation on the exterior surface. This behavior is unacceptable for multiple fill cycles or long-term storage.

[0011] Therefore, what is needed in the art is a cost-effective method for insulating large liquid hydrogen gas storage vessels. Summary of the Invention

[0012] FIELD OF THE DISCLOSURE The present disclosure relates generally to cryogenic vessels for storing liquid hydrogen.

[0013] In one embodiment, a liquid gas storage vessel is described. The liquid gas storage vessel includes an inner shell forming a cavity and an outer shell forming an insulating space between the inner shell and the outer shell. A first insulating layer is disposed around the inner shell within the insulating space. The first insulating layer is formed of a closed-cell insulating material. A second insulating layer is disposed within the insulating space between the first insulating layer and the outer shell.

[0014] In another embodiment, a liquid gas storage vessel is described. The liquid gas storage vessel includes an inner shell forming a cavity and an outer shell forming an insulating space between the inner shell and the outer shell. A first insulating layer is disposed within the insulating space and around the inner shell formed of a closed-cell insulating material. A second insulating layer is disposed within the insulating space between the first insulating layer and the outer shell. A membrane layer is disposed between the first insulating layer and the second insulating layer.

[0015] In another embodiment, a liquid gas storage vessel is described. The liquid gas storage vessel includes an inner shell forming a cavity and an outer shell forming an insulating space between the inner shell and the outer shell. A first insulating layer is disposed within the insulating space and around the inner shell formed of a closed-cell insulating material. Gas is disposed within the insulating space between the first insulating layer and the outer shell.

[0016] So that the above features briefly summarized above can be understood in detail, a more particular description can be had by reference to exemplary embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings depict only typical exemplary embodiments and are not to be considered as limiting the scope thereof. [Brief explanation of the drawings]

[0017] [Figure 1]1 is a schematic cross-sectional side view of a liquid hydrogen storage vessel according to an embodiment described herein. [Figure 2] 1 is a schematic cross-sectional side view of a liquid hydrogen storage vessel according to an embodiment described herein. [Figure 3A] 2 is an enlarged view of a portion of a wall forming the liquid hydrogen storage vessel of FIG. 1 according to embodiments described herein. [Figure 3B] 3 is an enlarged view of a portion of a wall forming the liquid hydrogen storage vessel of FIG. 2 according to embodiments described herein. DETAILED DESCRIPTION OF THE INVENTION

[0018] For ease of understanding, where possible, like reference numerals have been used to indicate like elements common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

[0019] The present disclosure generally relates to cryogenic vessels for storing liquid hydrogen. More specifically, the present disclosure relates to cryogenic vessels having multiple insulation layers that reduce cryopumping and enable low-cost manufacturing and maintenance of large liquid hydrogen storage vessels. The cryogenic vessels include a first insulation layer comprising a closed-cell polymer foam that can condense and prevent runaway cryopumping due to reduced permeability. Additionally, the cryogenic vessels include a second insulation layer comprising perlite or glass microspheres that can reduce the flow permeability to less than 40 Darcy, thereby reducing runaway cryopumping due to reduced permeability. Advantageously, the cryogenic vessels of the present disclosure can provide improved storage capacity compared to conventional cryogenic vessels, with the cryogenic vessels providing a storage capacity of about 25 to about 60 years.

[0020] A storage vessel capable of insulating liquid hydrogen without a vacuum and without liquefying the gas against a cold surface would significantly reduce the cost of large-scale liquid hydrogen storage compared to conventional liquid hydrogen storage vessels. In the embodiments described herein, an inner shell contains the liquid hydrogen product. The space between the outer shell and the inner shell includes at least two layers of insulation. The insulation adjacent to the inner shell is known as the inner insulation layer. The insulation between the inner insulation layer and the outer shell is known as the outer insulation layer.

[0021] The outer insulating layer is filled with gas to maintain a pressure in the insulating space near atmospheric pressure outside the outer vessel so that external pressure on the outer vessel is substantially reduced. This reduces the cost of the outer vessel. If the inner vessel contracts due to the cold liquid hydrogen product or if gas condenses, additional gas is supplied to the outer insulating layer to prevent a drop in pressure. The contraction of the inner vessel may depend on the radius of the inner vessel multiplied by the temperature difference between ambient temperature and the inner vessel temperature. At least one embodiment utilizes a low thermal conductivity gas, such as nitrogen or argon, in the insulating space, e.g., the inner insulating layer and / or the outer insulating layer.

[0022] The thermal insulation layer structures described herein can be used in any application that stores or transports cryogenic liquids, such as pipes. For example, the thermal insulation layer structures described herein can store liquid helium or higher temperature liquids. While a spherical liquid gas storage vessel is shown, the thermal insulation layers, membranes, and shell structures described herein can also be used with cylindrical storage vessels or storage vessels of other shapes.

[0023] If the liquid hydrogen product must be stored at pressures significantly above ambient pressure, the simplest shape is a sphere, although non-spherical pressure vessel shapes (generally having rounded shapes) are also possible. If the liquid hydrogen product can be stored at or near ambient pressure vessels of other shapes, such as cylinders, they can be used. The insulating space can have a consistent thickness throughout to reduce interfacial temperature variations.

[0024] FIG. 1 shows a schematic cross-sectional side view of a liquid gas storage vessel 100. The liquid gas storage vessel 100 includes an inner shell 102 that defines a cavity 104. The cavity 104 is defined by an inner surface 122 of the inner shell 102. The cavity 104 is configured to hold liquid hydrogen or another liquid gas. The cavity 104 has a capacity of 3,000 m 3 Larger, e.g. 4,000m 3 Larger, e.g. 5,000m 3 Larger, e.g. 6,000m 3 Larger, e.g. 6,500m 3 Larger, e.g. 7,000m 3 Larger, e.g., about 10,000 m 3 Larger, e.g., about 50,000 m 3 Larger, e.g., about 75,000 m 3 Larger, e.g., about 100,000 m 3 Larger, e.g., about 150,000 m 3 Larger, e.g., about 200,000 m 3 In some embodiments, the volume is about 5,000 m 3 ~about 250,000m 3 , or more, e.g., about 100,000 m 3 ~About 200,000m 3 The inner shell 102 is formed of a cryogenic metal material, such as cryogenic steel or another cryogenic metal alloy, that is available at a temperature of about 20 Kelvin. The inner shell 102 may be substantially spherical. In some embodiments, the inner shell 102 may be cylindrical with hemispheres on either end, or may have a polygonal cross section with rounded corners. Without being bound by theory, rounded corners may reduce stress concentrations compared to sharp corners, and rounded corners may reduce stress cracking in the insulation.

[0025] The outer shell 106 is formed around the inner shell 102. An insulating space 105 is formed between the inner shell 102 and the outer shell 106. The insulating space 105 includes at least two insulating layers, such as a first insulating layer 108 and a second insulating layer 110. The first insulating layer 108 is disposed around the inner shell 102 such that the first insulating layer 108 is wrapped around the inner shell 102 and covers the outer surface 120 of the inner shell 102. The first insulating layer 108 is attached to the outer surface 120 of the inner shell 102. The first insulating layer 108 is chemically bonded to the outer surface 120, which may include forming a bond using an epoxy bond and / or forming a bond via a reaction between the first insulating layer 108 and the outer surface 120. The first insulating layer 108 is a closed-cell insulating material. Closed-cell foams include polyethylene, polyurethane, polyisocyanurate, and polystyrene foam.

[0026] Closed-cell foams are formed by cells with thin polymer membranes arranged in a polyhedral shape, e.g., about 0.01 mm to about 1.0 mm, e.g., about 0.01 mm to about 0.5 mm, about 0.05 mm to about 0.1 mm, or about 0.07 mm to about 0.1 mm. The cells are filled with a gas, such as a blowing agent, which expands the cells in the foam. For example, the blowing agent can include an unsaturated organic compound such as a hydrofluoroolefin. At room temperature, atmospheric gases, such as nitrogen, can diffuse into the cells, where the blowing agent diffuses.

[0027] As the outer surface 120 of the inner shell cools, the gas in the cells of the first insulation layer 108 adjacent to the outer surface 120 also cools. The gas can liquefy and / or freeze. As the gas liquefies and / or freezes, the pressure in the cells decreases, creating a pressure differential across the cell walls of the closed-cell foam. The pressure differential can be between about 0.01 atm and about 1 atm, e.g., between about 0.01 atm and about 0.5 atm, between about 0.01 atm and about 0.1 atm, or between about 0.01 atm and about 0.05 atm. If the cell walls of the closed-cell foam are gas permeable, gas can diffuse from the surrounding higher-pressure cells into the lower-pressure cells and liquefy. This process can continue until the cells adjacent to the outer surface 120 are substantially filled with liquefied and / or frozen gas. If the outer surface 120 is warmed, such as during maintenance, the liquefied and / or frozen gas can vaporize and rupture the cells.

[0028] To prevent damage, the closed-cell foam can be cryogenically cooled, which can reduce and / or prevent gas diffusion into the cells of the closed-cell foam due to the reduced permeability of the closed-cell foam. Without being bound by theory, reducing the permeability of the closed-cell foam reduces the likelihood of the closed-cell foam bursting when heated. Furthermore, without being bound by theory, the first insulation layer 108 can reduce the complexity of thermal insulation damage when heating the inner shell 102.

[0029] The first insulating layer 108 is filled with a first gas, such as a blowing agent, nitrogen, or a nitrogen-containing gas mixture. For example, the first insulating layer 108 can be initially filled with a hydrofluoroolefin first gas, and after a period of time, such as seconds, minutes, hours, days, years, or decades, the first insulating layer 108 can be filled with a second nitrogen gas. In some examples, the first insulating layer 108 can be filled with air at a concentration similar to that found in ambient air. The first insulating layer 108 is used adjacent to the inner shell 102, and is thick enough to ensure that the temperature of the outer surface 128 of the first insulating layer 108 exceeds the condensation temperature of the gas in the second insulating layer 110, such as approximately 77 Kelvin (the point at which nitrogen boils or liquefies).

[0030] The closed-cell insulation material forming the first insulation layer 108 has a cell size (diameter) of about 1 μm to less than about 1 cm, such as 0.1 mm to about 1.0 mm. For example, the pore size of the closed-cell insulation material may be about 10 μm to about 100 μm. The first conductivity of the first insulation layer 108 is about 0.0001 W / (m·K) to about 0.050 W / (m·K), for example, about 0.010 W / (m·K) to about 0.040 W / (m·K), for example, about 0.010 W / (m·K) to about 0.030 W / (m·K), for example, about 0.015 W / (m·K) to about 0.030 W / (m·K), for example, about 0.020 W / (m·K) to about 0.030 W / (m·K).

[0031] A second insulating layer 110 is also disposed within the insulating space 105. The second insulating layer 110 is disposed between the first insulating layer 108 and the outer shell 106. The second insulating layer 110 is disposed inside the outer surface 128 of the first insulating layer 108 and the inner surface 124 of the outer shell 106. The cross section of the inner surface 124 of the outer shell 106 is substantially circular. The thermal conductivity of the second insulating layer 110 may be higher than that of the first insulating layer 108. The second insulating layer 110 may be a gas, foam, aerogel, expanded perlite, glass microspheres, or another insulator with low thermal conductivity. The glass microspheres may have a diameter of about 1 nm to about 100 μm, e.g., about 1 nm to about 10 μm, about 500 nm to about 10 μm, or about 500 nm to about 1 μm. The second insulating layer 110 may be a closed-cell foam.

[0032] In at least one embodiment, the second insulating layer 110 can include perlite having a flow permeability of about 40 Darcy to about 50 Darcy. In at least one embodiment, the second insulating layer 110 can include glass microspheres having a flow permeability of about 3 Darcy to about 10 Darcy. In at least one embodiment, the second insulating layer 110 can include a mixture of perlite and glass microspheres. The mixture can include about 1% to about 99% perlite by weight and about 1% to about 99% glass microspheres by weight. For example, the mixture can include about 60% to about 99% perlite by weight and about 1% to about 40% glass microspheres by weight. As a further example, the mixture can include about 80% to about 99% perlite by weight and about 1% to about 20% glass microspheres by weight. The mixture can include a flow permeability of about 6 Darcy to about 45 Darcy, e.g., about 6 Darcy to about 40 Darcy, about 6 Darcy to about 30 Darcy, about 6 Darcy to about 20 Darcy, or about 10 Darcy to about 20 Darcy. Without being bound by theory, a second insulating layer having a flow permeability of about 6 Darcy to about 40 Darcy can reduce runaway cryopumping, thereby increasing the efficiency of the temperature insulation of the second insulating layer 110.

[0033] The second insulation layer 110 is filled with a second gas, which may be a single gas or a combination of gases. The second gas may be greater than 50% nitrogen, greater than 50% argon, or greater than 50% nitrogen and argon, as measured by partial pressure. In some embodiments, the second gas combination may be greater than 60% nitrogen and argon, e.g., greater than 70%, e.g., greater than 80%, e.g., greater than 90% nitrogen and argon. The nitrogen and / or argon concentration in the first insulation layer 108 may be maintained by exposing the first insulation layer 108 to a nitrogen and / or argon gas source. In some examples, dry air may be utilized. Nitrogen and / or argon gas may be used in the second insulation layer 110 during formation of the second insulation layer 110 on the outer surface 128 of the first insulation layer 108.

[0034] The concentration of hydrogen or helium gas is reduced within the second insulating layer 110 due to the higher electrical conductivity of hydrogen and helium compared to nitrogen and argon.

[0035] The second conductivity of the second insulating layer 110 is approximately 0.010 W / (m·K) to 0.100 W / (m·K). The thermal conductivity of the first insulating layer 108 may be less than twice the thermal conductivity of the second insulating layer 110, for example, less than three times the thermal conductivity of the second insulating layer 110, for example, less than four times the thermal conductivity of the second insulating layer 110, for example, less than five times the thermal conductivity of the second insulating layer 110, for example, less than seven times the thermal conductivity of the second insulating layer 110, or for example, less than ten times the thermal conductivity of the second insulating layer 110.

[0036] At least two insulating layers are disposed between the inner shell 102 and the outer shell 106, for example, within the insulating space 105. The first insulating layer 108, which may be a closed-cell foam, can prevent runaway cryopumping. The second insulating layer 110 is also suitable for reducing manufacturing costs and reducing the gas supply required to maintain pressure within the outer insulating layer. The gas within the second insulating layer 110 is a gas or gas mixture with a relatively low conductivity that liquefies at approximately 20 K, the temperature of liquid hydrogen. The temperature of the outer edge of the first insulating layer is higher than the condensation temperature of the gas or gas mixture within the second insulating layer to prevent condensation and runaway cryopumping. The pressure is maintained substantially above a perfect vacuum, reducing the cost of the outer vessel. The pressure in the second insulating layer 110 is maintained at about 0.5 atmospheres to about 2 atmospheres, for example, about 0.5 atmospheres to about 1.5 atmospheres, for example, about 0.75 atmospheres to about 1.25 atmospheres, for example, about 0.8 atmospheres to about 1.2 atmospheres, for example, about 0.9 atmospheres to about 1.1 atmospheres, for example, about 0.95 atmospheres to about 1.05 atmospheres, for example, about 1 atmosphere. The pressure in the first insulating layer 108 may be about 1.0 atmosphere on the first surface, but drops to about 0.2 atmospheres or less, or about 0.1 atmospheres or less, near the inner tank 102.

[0037] Optionally, an interleaved layer can be disposed between the first insulation layer 108 and the second insulation layer 110. The interleaved layer can include a composite, cement, metal, polymer, foam, or a combination thereof. The interleaved layer can include a thickness of about 0 mm to about 200 mm, e.g., about 10 mm to about 150 mm, about 50 mm to about 150 mm, or about 50 mm to about 100 mm. Without being bound by theory, the interleaved layer can stop crack formation and increase the strength of the first insulation layer 108 and / or the second insulation layer 110 by preventing crack propagation throughout the insulation space 105.

[0038] Optionally, the interleaved layer can include a foam layer. The foam layer can be disposed on and / or over the second insulation layer 110 to form a braid, e.g., a layer of collapsed foam cells. Without being bound by theory, the braid can reduce permeability due to increased foam density, thereby reducing cryogenic pumping and increasing cryogenic cooling capacity.

[0039] The conduit 112 extends into the cavity 104 and penetrates each of the inner shell 102, the first insulation layer 108, the second insulation layer 110, and the outer shell 106. The conduit 112 may be a pipe or tube that extends into the cavity 104 to fill or drain liquid hydrogen from the cavity 104. The conduit 112 is positioned so that an open end of the conduit 112 is within the cavity 104 and the other end of the conduit 112 is connected to a hydrogen source 114 outside the body of the liquid hydrogen storage container 100. The hydrogen source 114 may include a pump or condenser, as well as one or more feed lines to various other hydrogen sources 114. While only a single conduit is shown, it should be understood that more than one conduit may be included, such as a filling conduit, a withdrawal conduit, a conduit for venting boil-off gas, and optionally other conduits. In some examples, filling and evaporation may pass through conduits through the top, and withdrawal lines may pass through the top or bottom. Other configurations are possible.

[0040] The support skirt 118 is utilized to support the body of the liquid hydrogen storage vessel 100. The support skirt 118 may be a concrete skirt outside the exterior surface 126 of the outer shell 106, then transition to a metal skirt either just outside the exterior surface 126 or as the skirt passes the exterior surface 126 of the outer shell 106. The support skirt 118 may be a plurality of discontinuous columns outside the exterior surface 126 of the outer shell 106, such that the plurality of discontinuous columns provide support to the outer shell 106. The portion of the support skirt 118 that passes through the outer shell 106 and into the insulation space 105 may include a plurality of hanger rods, such that the support skirt 118 is discontinuous within the insulation space 105 such that the entire first insulation layer 108 and the entire second insulation layer 110 remain in fluid communication and the insulation space 105 is not divided into separate chambers by the support skirt 118.

[0041] 2 shows a schematic cross-sectional side view of another liquid hydrogen storage vessel 200. The liquid hydrogen vessel 200 includes an intermediate shell 210. The intermediate shell 210 may be an impermeable membrane, such as a metal or non-metal, depending on the embodiment and the type of insulation utilized for one or both of the first insulation layer 108 and the second insulation layer 110. In some examples, when an impermeable membrane is used as the intermediate shell, closed-cell foam and / or open-cell foam may be used as the first insulation layer 108.

[0042] The intermediate shell 210 is an impermeable membrane that prevents gas or liquid from passing through the intermediate shell 210, yet the intermediate shell 210 can still flex and bend to maintain contact with both the first insulation layer 108 and the second insulation layer 110. The intermediate shell 210 may be impermeable at temperatures between about 50 Kelvin and about 100 Kelvin, such as between about 60 Kelvin and about 90 Kelvin, such as between about 70 Kelvin and about 90 Kelvin, for example, between about 75 Kelvin and about 85 Kelvin. The intermediate shell 210 is at least partially impermeable because its permeability coefficient is sufficiently low to provide a predetermined level of impermeability for the use of the storage vessel. Without being bound by theory, the permeability coefficient may be low enough to prevent and / or reduce damage to the first insulation layer when the tank is warmed during maintenance and / or when not in cryogenic cooling operation.

[0043] In embodiments in which the intermediate shell 210 is an impermeable membrane, the membrane layer may be one or a combination of epoxy, polyethylene terephthalate (Mylar), aluminized polyethylene terephthalate, polypropylene, polyimide, polyetherimide, polyetheretherketone, or various metal foils. Other materials are contemplated but not explicitly listed herein. The membrane may have a resistance of 400 kg / mm ​​at a temperature of approximately 77 Kelvin. 2 exceeding, for example, 500 kg / mm 2 exceeding, for example, 600 kg / mm 2 exceeding, for example, 700 kg / mm 2The membrane can have an elastic modulus greater than 1 / 2 mm. The membrane can have a thickness of about 0.1 mm to about 10 mm, e.g., about 0.1 mm to about 8 mm, about 0.5 mm to about 5 mm, or about 1 mm to about 3 mm. Without being bound by theory, a membrane thickness of about 0.1 mm to about 10 mm can allow the membrane to flex while covering the first insulating layer 108, avoiding tears and / or cracks. The elastic modulus allows the membrane to flex along with the first insulating layer 108 and the second insulating layer 110 as the first insulating layer 108 and / or the inner shell 102 contract and expand during cooling and heating of the first insulating layer 108 and the inner shell 102. The membrane also helps seal the first insulating layer 108 from the second insulating layer 110. Therefore, if there are gaps or cracks in the first insulating layer 108, the presence of the membrane can reduce or eliminate the effects of cryopumping. The use of a flexible membrane intermediate shell 210 may further allow for additional materials, such as open-cell foam, to be utilized as part of the first insulation layer 108.

[0044] Optionally, a sealant is also disposed around any openings in the intermediate shell 210 so that there is no fluid communication between the first insulation layer 108 and the second insulation layer 110, even if something, such as the support skirt 118, passes through the intermediate shell 210. The sealant can include an epoxy resin, such as LOCTITE® Stycast 2850. The sealant can include a diphenol resin, such as epichlorohydrin-4,4'-isopropylidene. The sealant must be able to provide a seal at temperatures below 100 Kelvin.

[0045] Optionally, the collar can be welded to the skirt, piping, and / or support that penetrates the first insulation layer. The collar can include a film chemically bonded to an outer surface of the collar and to the first insulation layer. Without being bound by theory, welding a collar with a film to the skirt, piping, and / or support that penetrates the first insulation layer can increase the cryogenic cooling capacity of the cryocontainer.

[0046] The intermediate shell 210, also referred to as an interlayer, is disposed between the first insulation layer 108 and the second insulation layer 110. In such an example, the intermediate shell 210 may be metal, polymer, or a combination thereof.

[0047] The intermediate shell 210 may be formed of a material that is not self-supporting or is otherwise flexible. The first insulation layer 108 may be self-supporting if the intermediate shell 210 is an impermeable membrane. In such an example, the first insulation layer 108 has sufficient structural rigidity to support the pressure exerted by the gas in the second insulation layer 110. Spray-on foam and aerogel blankets are examples of self-supporting materials that may be used for the first insulation layer 108. The insulating material of the first insulation layer 108 may include a compressive strength of about 14 psi to about 100 psi, e.g., about 14 psi to about 90 psi, about 20 psi to about 80 psi, or about 30 psi to about 70 psi, and may support loads that penetrate the impermeable membrane from both the pressure differential and any forces exerted by the granular material used to insulate the second insulation layer 110.

[0048] The liquid hydrogen storage vessel 200 can include one or more gas inputs and one or more pumps or compressors in fluid communication with the first insulating layer 108. In some examples, the one or more gas inputs and one or more pumps are part of or function as a pressure regulator. The one or more pumps or compressors fluidly coupled to the first insulating layer 108 help maintain a predetermined pressure within the first insulating layer 108. The liquefaction or freezing of gas within the first insulating layer 108 creates a vacuum (e.g., a pressure below atmospheric pressure) whose absolute value may vary from cell to cell or which may exist in a nonlinear gradient from one surface to the opposite surface. During operation, the pressure within the cells of the foam of the first insulating layer can reach a predetermined level of vacuum (e.g., subatmospheric pressure), providing beneficial thermal conductivity within the cells.

[0049] A second gas source 208 is in fluid communication with the second insulation layer 110 via a conduit 204. The second gas source 208 may be similar to the first gas source 206 in that it may include a connection to one or more pumps, compressors, or one or more other fluid delivery systems. The conduit 204 is in fluid communication with the second insulation layer 110 but not with the first insulation layer 108. When a first gas source is used, the first insulation layer 108 and the second insulation layer 110 receive different gases from different gas sources 206, 208.

[0050] Figure 3A shows an enlarged view of a portion of a wall forming the liquid hydrogen storage vessel 100 of Figure 1. Over the portion of the liquid hydrogen storage vessel 100 is a graph 300 showing a schematic diagram of the temperature of the liquid hydrogen storage vessel 100 at various points within the body of the liquid hydrogen storage vessel 100. The graph 300 includes a vertical axis 302 that indicates temperature (T) and a horizontal axis 304 that indicates position within the liquid hydrogen storage vessel 100 relative to the center of the cavity 104.

[0051] The cavity 104 is maintained at a first temperature T1. The first temperature T1 is below the boiling point of the gas within the cavity 104. Therefore, the first temperature T1 is below about 20.3689 Kelvin while storing liquid hydrogen. The temperature is increased to a second temperature T2 within the inner shell 102. The second temperature T2 may be fairly similar to the first temperature T1, such as between about 20 Kelvin and about 25 Kelvin, or between about 20 Kelvin and about 22 Kelvin. In some examples, the difference between the first temperature T1 and the second temperature T2 is less than 2 Kelvin, such as less than 1 Kelvin, or less than 0.5 Kelvin. The second temperature T2 may be directly related to the first thickness L1 of the inner shell 102. The first thickness L1 is about 10 mm to about 100 mm, for example, about 10 mm to about 75 mm, for example, about 10 mm to about 50 mm, for example, about 15 mm to about 45 mm, for example, about 20 mm to about 45 mm, for example, about 20 mm to about 30 mm.

[0052] The temperature is increased from the second temperature T2 to a third temperature T3 through the first insulating layer 108. The third temperature T3 is higher than the condensation point of the gas in the second insulating layer 110, for example, higher than the condensation point of nitrogen or argon. The third temperature T3 can be less than about 10 degrees, for example, less than about 5 degrees, above the condensation point of the gas in the second insulating layer 110. When the gas in the second insulating layer 110 is nitrogen, the third temperature T3 is greater than 77 Kelvin, for example, between about 78 Kelvin and about 80 Kelvin, for example, between about 78 Kelvin and about 90 Kelvin, for example, between about 78 Kelvin and about 100 Kelvin. In another example, the third temperature T3 can be between 150 Kelvin and 170 Kelvin to further reduce the possibility of condensation. In yet another example, the third temperature T3 can be ambient temperature.

[0053] To reach temperatures above 77 Kelvin, the first insulation layer 108 has a thickness L2 of about 0.1 meters to about 5 meters, e.g., about 0.55 meters to about 4 meters, e.g., about 1 meter to about 4 meters, e.g., about 1.1 meters to about 3.5 meters, e.g., about 2 meters to about 3 meters. The total thickness of both insulation layers 108, 110 combined is in the range of about 0.2 meters to about 5 meters, e.g., 1 meter to about 3 meters, resulting in easier and cheaper construction, transportation, and maintenance. The relative thicknesses of the insulation layers 108, 110 are selected to achieve a predetermined temperature T3, while the total thickness (and conductivity) of the first insulation layer 108 and the second insulation layer 110 are selected to provide a predetermined amount of leakage / boil-off rate (or lack thereof).

[0054] As the second insulation layer 110 extends from the outer surface 128 of the first insulation layer 108 to the inner surface 124 of the outer shell 106, the temperature increases until it reaches a fourth temperature T4. The fourth temperature is between the third temperature T3 and the ambient temperature T6 surrounding the outer surface 126 of the outer shell 106. Thus, the fourth temperature T4 may be between about 80 Kelvin and about 320 Kelvin, e.g., between about 100 Kelvin and about 315 Kelvin, e.g., between about 200 Kelvin and about 310 Kelvin, e.g., between about 250 Kelvin and about 310 Kelvin, e.g., between about 273 Kelvin and about 310 Kelvin. In one example, the fourth temperature T4 is within about 2 to 5 Kelvin of the ambient temperature T6. The second insulation layer has a third thickness L3. The third thickness L3 is as described above.

[0055] As the outer shell 106 extends from the inner surface 124 to the outer surface 126, the temperature within the outer shell 106 increases from a fourth temperature T4 to a fifth temperature T5. The fifth temperature T5 is close to the ambient temperature T6 of the environment surrounding the outer shell 106, such as between about 250 Kelvin and about 315 Kelvin, between about 265 Kelvin and about 310 Kelvin, or between about 273 Kelvin and about 305 Kelvin. The thickness of the outer shell 106 is a fourth thickness L4. The fourth thickness L4 is less than the first thickness L1 of the inner shell 102 because the inner shell 102 has a pressurized cavity 104 formed by the inner surface 122. The outer shell 106 provides overall support and protection for the insulation layers 108, 110. However, in some situations where additional protection of the insulation and / or contents is desired, it is contemplated that the thickness L4 may be greater. The fourth thickness L4 is about 10 mm to about 100 mm, for example, about 10 mm to about 50 mm, for example, about 10 mm to about 30 mm, for example, about 14 mm to about 25 mm, for example, about 15 mm to about 20 mm.

[0056] 3B shows an enlarged view of a portion of the wall forming the liquid hydrogen storage vessel 200 of FIG. 2. Over the portion of the liquid hydrogen storage vessel 200 is a graph 350 showing a schematic representation of the temperature of the liquid hydrogen storage vessel 200 at various points within the body of the liquid hydrogen storage vessel 200. Graph 350 is similar to graph 300 of FIG. 3A, but further includes a portion corresponding to the temperature gradient within the intermediate shell 210. The temperature within the intermediate shell 210 ranges from a third temperature T3 to a seventh temperature T7. The seventh temperature may be substantially the same as the third temperature T3, or may be slightly greater than the third temperature T3, for example, between about 0 Kelvin and about 3 Kelvin greater than the third temperature T3.

[0057] The intermediate shell 210 has a fifth thickness L5 of about 10 mm to about 100 mm, for example, about 10 mm to about 75 mm, for example, about 10 mm to about 50 mm, for example, about 15 mm to about 45 mm, for example, about 20 mm to about 45 mm, for example, about 20 mm to about 30 mm. The fifth thickness L5 is between the first thickness L1 and the fourth thickness L4. However, other thicknesses and / or relative thicknesses are contemplated.

[0058] The embodiments described herein enable better and more reliable systems for insulating liquid gas storage vessels, such as liquid hydrogen storage vessels. The embodiments described herein are more economical and easier to manufacture. The disclosed embodiments reduce cryopumping within the first insulating layer 108 by using closed-cell or aerogel, which reduces gas diffusion through the first insulating layer 108. The second insulating layer 110 can be more insulating than the first insulating layer 108 by using a mixture of glass microspheres and perlite, thereby improving thermal insulation performance compared to conventional insulating devices.

[0059] Some embodiments, which can be combined with other embodiments, utilize an additional intermediate or middle shell 210 (e.g., a membrane) between the first insulating layer 108 and the second insulating layer 110. The middle shell 210 may be an impermeable membrane that can flex to accommodate changes in the dimensions of the first insulating layer 108 or metal / metal alloy shell. The impermeable membrane can further reduce the possibility of cryopumping.

[0060] While the forgoing is directed to embodiments of the present disclosure, other and further embodiments of the present disclosure may be devised without departing from the basic scope thereof, which scope is determined by the following claims.

Claims

1. A liquid gas storage vessel, an inner shell forming a cavity; an outer shell forming a thermal insulation space between the inner shell and the outer shell; a first insulation layer disposed within the insulation space and around the inner shell, the first insulation layer being formed from a closed-cell insulation material; and a second insulating layer disposed within the insulating space between the first insulating layer and the outer shell; A liquid gas storage vessel comprising:

2. The liquid gas storage vessel of claim 1 , wherein the inner shell comprises a cryogenic metal.

3. The cavity is about 3,000 m ３ 3. The liquid gas storage vessel of claim 2, comprising a volume greater than

4. 10. The liquid gas storage vessel of claim 1, wherein the closed-cell insulation material comprises a first gas, the first gas comprising greater than 50% nitrogen.

5. 10. The liquid gas storage vessel of claim 1, wherein the second insulating layer comprises a second gas, the second gas comprising greater than 50% argon.

6. 10. The liquid gas storage vessel of claim 1, wherein the closed-cell insulating material comprises closed-cell foam.

7. The liquid gas storage vessel of claim 6 , wherein the second insulating layer comprises a bulk fill material.

8. 8. The liquid gas storage vessel of claim 7, wherein the bulk fill material comprises one or more of perlite, glass microspheres, or silica aerogel, or a mixture thereof.

9. 9. The liquid gas storage vessel of claim 8, wherein the second insulating layer comprises a mixture of perlite and glass microspheres.

10. 10. The liquid gas storage vessel of claim 9, wherein the mixture comprises about 60% to about 99% by weight perlite and about 1% to about 40% by weight glass microspheres.

11. A liquid gas storage vessel, an inner shell forming a cavity; an outer shell forming a thermal insulation space between the inner shell and the outer shell; a first insulation layer disposed within the insulation space and around the inner shell, the first insulation layer being formed from a closed-cell insulation material; a second insulating layer disposed within the insulating space between the first insulating layer and the outer shell; a membrane layer disposed between the first and second thermal insulation layers; A liquid gas storage vessel comprising:

12. 12. The liquid gas storage vessel of claim 11, wherein the membrane layer comprises one or more of aluminized mylar, mylar, polyurea, epoxy, water glass, or xerogel.

13. 12. The liquid gas storage vessel of claim 11, wherein the closed-cell insulating material comprises closed-cell foam.

14. 12. The liquid gas storage vessel of claim 11, wherein the second insulating layer comprises a bulk fill material comprising one or more of perlite, glass microspheres, or silica aerogel, or a mixture thereof.

15. 15. The liquid gas storage vessel of claim 14, wherein the second insulating layer comprises a mixture of perlite and glass microspheres, the mixture comprising from about 60% to about 99% by weight perlite and from about 1% to about 40% by weight glass microspheres.

16. 12. The liquid gas storage vessel of claim 11, wherein the first insulating layer has a thickness of about 0.1 meters to about 1.0 meters.

17. 12. The liquid gas storage vessel of claim 11, further comprising one or more gas inputs and one or more pumps or compressors in fluid communication with the second insulation layer.

18. A liquid gas storage vessel, an inner shell forming a cavity; an outer shell forming a thermal insulation space between the inner shell and the outer shell; a first insulation layer disposed within the insulation space and around the inner shell, the first insulation layer being formed from a closed-cell insulation material; and a gas disposed in the insulation space between the first insulation layer and the outer shell; A liquid gas storage vessel comprising:

19. 20. The liquid gas storage vessel of claim 18, wherein the gas comprises more than 50% argon.

20. 20. The liquid gas storage vessel of claim 18, wherein the gas comprises more than 50% nitrogen.

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