Containment systems for liquid hydrogen.

Abstract

The present invention relates to a containment system for storing liquid hydrogen (3), comprising one or more walls forming a containment space (2). At least one of the one or more walls comprises an inner barrier layer (11), an outer barrier layer (12) and one or more spacer elements (14) arranged between the inner barrier layer (11) and the outer barrier layer (12) to separate the first barrier layer (11) and the second barrier layer (12), thereby creating a space for a vacuum layer (13) between the inner barrier layer (11) and the outer barrier layer (12). The outer barrier layer (12) is made of cryogenic ice having a temperature below -150°C.

Description

[Technical field]

[0001] The present invention relates to a containment system for storing and / or transporting liquid hydrogen. Additionally, the present invention relates to a method for manufacturing such a containment system. The containment system may be used for the storage and / or transport of liquid hydrogen, including for onshore and offshore applications in the liquid hydrogen supply chain. [Background technology]

[0002] Hydrogen is an important industrial gas used in oil refining, the fertilizer industry and several other chemical processes. It is expected that hydrogen may also play an important role as an energy carrier, especially in the transportation sector. Hydrogen is further expected to serve as an energy storage medium by using it as an energy buffer to address intermittency issues that arise in the power grid as a result of using green electricity (e.g. electricity generated using wind or solar power).

[0003] Due to the volume gain, the gaseous hydrogen can be suitably liquefied and then stored for later use or distribution. Storage of liquid hydrogen can be done in a containment system. The containment system can be a land-based containment system or an offshore containment system. Distribution can be done by providing one or more containment systems on ships / tankers (for ocean transport) or trucks.

[0004] To liquefy hydrogen, it needs to be cooled to its boiling point, which for hydrogen at normal pressure is approximately minus 253°C. This relatively low temperature introduces specific requirements on the containment system in order to make it suitable for containing liquid hydrogen.

[0005] The materials used need to be strong enough at such cryogenic temperatures to hold liquid hydrogen. Preferably, the containment system will not leak liquid hydrogen. The containment system preferably has sufficient structural strength to provide safe and reliable storage of liquid hydrogen. When cooling the containment system (e.g., from ambient temperature) to cryogenic temperatures, thermal cracking due to material contraction should be avoided.

[0006] For efficient storage, the temperature of the liquid hydrogen stored in a cryogenic containment system is required to remain close to the temperature at which it was loaded. Heat ingress into the containment system results in boiling of the carried liquid hydrogen and the gaseous hydrogen produced (Boil Off Gas - BOG) will increase pressure within the containment system if not removed. Means for managing the BOG can include means for re-liquefying the BOG so that it can be re-inserted. However, re-liquefaction requires a significant amount of power and equipment.

[0007] It is therefore preferable to reduce heat ingress, and thereby reduce BOG, by providing a well-insulated containment system.

[0008] To improve insulation, the walls of the containment system can be made from several different layers to reduce heat intrusion.

[0009] No. 3,267,685 discloses a vessel for storing liquids at cryogenic temperatures, the vessel comprising a rigid outer shell, insulation lining the outer shell, a plurality of liquid impermeable membranes lining the insulation, and a freeze seal structure including a sealant material sealingly engaging portions of the membranes. The sealant material may be water. No mention is made of the storage of liquid hydrogen.

[0010] US 2017 / 0030520 A1 discloses a method of making a wall structure for a vessel containing a liquid (such as LNG), the method including injecting a composite fluid into a cavity of the wall structure and freezing the composite fluid in the cavity to form a composite layer in the wall structure. The composite fluid may include water. There is no mention of storage of liquid hydrogen, nor is there any mention of the vacuum enhancing properties of cryogenic ice.

[0011] Korean Patent No. 2010 0022201 discloses a thermal insulation structure for LNG carrying cargo.

[0012] US Pat. No. 3,136,135 discloses a tanker for transporting cryogenic liquid cargoes such as LNG, methane, ethane, ethylene and mixtures thereof.

[0013] WO 2019 / 122757 describes a tank for storing liquids, such as liquid hydrogen, in which hollow glass microspheres are used.

[0014] Other publications include GLASS BUBBLES INSULATION FOR LIQUID HYDROGEN STORAGE TANKS (2009) by J.P. Sass ea (https: / / www.techapps.com / hs-fs / hub / 165629 / file-18313642-pdf / documents / technical_paper_glass_bubbles_insulation_for_liquid_hydrogen_storage_tanks.pdf) and RESEARCH AND DEVELOPMENT HISTORY OF GLASS BUBBLES BULK-FILL THERMAL INSULATION SYSTEMS FOR LARGE-SCALE CRYOGENIC LIQUID HYDROGEN STORAGE by J. Fesmire, CryoTestLab, NASA / KSC. They mention the use of glass bubbles such as TANKS(09 / 2017)(https: / / ntrs.nasa.gov / cations / 20180006604).

[0015] China Patent No. 201120842 describes a liquid hydrogen fuel tank. The tank wall is formed by several layers, among which is a vacuum insulation layer.

[0016] Creating a vacuum layer comes with its own challenges. Creating a high level vacuum layer between layers of a containment system is a time consuming process. In the context of a large cryogenic containment system, it can take days to create a vacuum. One of the issues is outgassing of materials from layers facing the vacuum layer. This creates challenges in creating and maintaining a vacuum for insulation purposes, as even small amounts of gas in the vacuum layer will conduct heat.

[0017] It is therefore an object to provide an improved containment system for storing liquid hydrogen. Summary of the Invention

[0018] The present invention provides a containment system (1) for storing liquid hydrogen (3), comprising one or more walls forming a containment space (2) for holding the liquid hydrogen (3), the containment space (2) containing the liquid hydrogen (3), the containment system (1) comprising: At least one of the one or more walls comprises an inner barrier layer (11), an outer barrier layer (12), and one or more spacer elements (14) disposed between the inner barrier layer (11) and the outer barrier layer (12) to separate the inner barrier layer (11) and the outer barrier layer (12), thereby forming a space for a vacuum layer (13) between the inner barrier layer (11) and the outer barrier layer (12); The outer barrier layer (12) is made of cryogenic ice having a temperature below -150°C; The vacuum layer (13) has a pressure of less than 0.01 Pa.

[0019] In this regard, it is noted that the above mentioned prior art documents such as U.S. Pat. No. 3,267,685 do not mention the storage of liquid hydrogen and / or do not appreciate the vacuum enhancing properties of the cryogenic ice used in the outer barrier layer according to the present invention.

[0020] The advantage of using an outer barrier layer made of cryogenic ice (water frozen at temperatures below -150°C) overcomes the problem of outgassing, since the vapor pressure of ice at cryogenic temperatures is very low. This makes it easier to create and maintain low pressure in the vacuum layer. The loading and presence of liquid hydrogen further improves the vacuum. This allows for a very economical method of achieving and maintaining a reliable vacuum in a surprisingly simple manner.

[0021] The term vacuum layer is used to refer to a layer having a low pressure, i.e., a pressure well below the ambient pressure. The pressure in the vacuum layer (P vac ) is preferably less than 0.01 Pa (P vac <0.01 Pa), more preferably less than 0.001 Pa (P vac <0.001 Pa).

[0022] The term ice is used to refer to water (H2O) that has been frozen into a solid state. Ice may contain some impurities or air bubbles, but such impurities or air bubbles impair insulating properties and are preferably kept to a minimum.

[0023] If the containment system is filled with liquid hydrogen fluid, the temperature of the ice will be relatively low, and therefore the ice is sometimes referred to as cryogenic ice.

[0024] The inner and / or outer barrier layers are at least partially made of ice. The parts of the inner and outer barrier layers made of ice may be formed of other materials, for example for structural reasons (e.g. the tops of the inner and outer barrier layers) or for specific functional reasons (e.g. to form manholes, ventilation inlets / outlets, fluid inlets / outlets, etc.).

[0025] The inner and outer barrier layers, made at least in part of ice, have an outer surface that directly faces the vacuum layer and, optionally for the inner barrier layer, the containment space, the term directly facing being used to indicate that the ice is suitably exposed to the vacuum layer or the containment space.

[0026] Ice has structural properties at cryogenic temperatures suitable for supporting liquid hydrogen with its low density. Cryogenic ice has a compressive strength of over 5 MPa and a tensile strength of over 1 MPa. Furthermore, the thermal conductivity of ice at cryogenic temperatures (3.4-5 W / mK) is suitable for effectively cooling the ice barrier before the vacuum space is cryogenically dried and the insulating filler (glass bubbles) is added.

[0027] The term "cryogenic" is used throughout this specification to refer to temperatures below -150°C, below -200°C, or even below -250°C.

[0028] Preferably, the outer barrier layer 12 is maintained at a temperature below −150° C. This has the advantage that the vacuum within the vacuum layer 13 is best maintained, thereby creating an effective level of insulation within the vacuum layer 13.

[0029] The containment space can have any suitable shape including cylindrical, with the cylinder axis being vertical or horizontal, spherical and cubic. Depending on the shape of the containment space, one or more walls of suitable shape may be provided. For example, in the case of a cubic shape, four side walls, a bottom wall and a top wall may be provided, while in the case of a spherical tank, only one spherical wall or two hemispherical walls placed on top of each other may be used.

[0030] The containment system may include one or more vent inlets / outlets (31) provided to prevent BOG buildup within the containment space and to allow steam or make-up gas to enter and exit the containment space during unloading and loading, respectively.

[0031] The containment system may comprise one or more fluid inlets / outlets (41), which may be combined or alternatively may be provided by separate fluid inlet(s) and fluid outlet(s).

[0032] The fluid inlet is connected or connectable to a liquid supply, such as a storage tank or a liquefaction train.

[0033] The fluid outlet is connected or connectable to a discharge pump preferably located outside the containment space, which is preferably an eductor system since such a system generates little or no undesirable high frequency vibrations in or near the tank piping structure.

[0034] The containment system may further comprise one or more vacuum outlets (51) forming a fluid connection between the space for the vacuum layer and the outside of the containment space, the vacuum outlets being connected or connectable to a vacuum pump (not shown) for pumping gas (air) from the vacuum space to create an initial vacuum and / or to further maintain the vacuum.

[0035] The term liquid hydrogen is used to refer to a liquid containing at least 95 mole percent hydrogen. In that context, the term cryogenic is used to refer to a temperature below −250° C. (e.g., −253° C.). Liquid hydrogen may be at or near ambient pressure.

[0036] According to one embodiment, a containment system for accommodating liquid hydrogen is provided, in which the inner barrier layer (11) is made of ice, preferably cryogenic ice having a temperature below -150°C.

[0037] The inner barrier layer faces the vacuum layer on one side and the containment space holding the liquid hydrogen on the other side. As mentioned before, the inner and outer barrier layers made of ice have a low temperature whose vapor pressure (suitable for vacuum insulating filler, e.g. glass bubbles) in use provides economical and energy efficient advantages over traditional / conventional vacuum containment systems / LIN jacketed containment systems for liquid hydrogen.

[0038] Better efficiency from this concept also results from avoiding the high costs of manufacturing by using hydrogen-friendly metal structures and manufacturing methods.

[0039] In addition to supporting economical vacuum maintenance, cryogenic ice forms an advantageous liquid barrier layer for liquid hydrogen, with added benefits regarding ease of vacuum layer formation and manufacture.

[0040] According to the present invention, the outer barrier layer (12) is made of cryogenic ice having a temperature below -150°C.

[0041] By making the outer barrier layer facing the vacuum cold enough to affect an ice vapor pressure of less than 1 Pa, the outgassing problem is greatly reduced, as the outer layer is cold enough to have a vapor pressure of less than 1 Pa.

[0042] According to one embodiment, a containment system is provided, in which both the inner barrier layer (11) and the outer barrier layer (12) are made from cryogenic ice having a temperature below -150°C.

[0043] By forming both inner and outer barrier layers of cryogenic ice, the vacuum layer is faced on both sides with layers of cryogenic ice, thereby significantly reducing outgassing problems and improving the reliability of vacuum containment.

[0044] The inner barrier layer may be at a temperature substantially equal to the temperature of the liquid hydrogen, and the outer barrier layer may be at a temperature higher than the temperature of the liquid hydrogen. The temperature of the inner barrier layer may be approximately -253°C, and the temperature of the outer barrier layer may be approximately -173°C. The outer barrier layer is preferably at a temperature low enough to minimize outgassing. Preferably, the temperature of the outer layer is higher than the condensation temperature of N2 and O2. Therefore, the outer barrier layer may be covered with one or more additional passive insulation layers to keep the outer barrier layer at a relatively low temperature.

[0045] According to one embodiment, a containment system is provided in which an outer barrier layer (12) is covered on the outside by one or more additional insulating layers.

[0046] Such an insulation layer keeps the outer barrier layer at a temperature well below ambient temperature, so that the operating costs for maintaining the outer cryogenic ice wall temperature are optimized. The outer barrier layer can be maintained at temperatures below -40°C, where the vapor pressure of frozen water is about 13 Pa and which is suitable for glass bubble vacuum insulation filling.

[0047] It may be sufficient to maintain the outer layer of ice at at least -40°C or below (depending on the boil-off required for the tank).

[0048] The additional insulating layer may be made from any suitable material, including expanded polystyrene or polyurethane foam (PUF).

[0049] According to one embodiment, a containment system is provided in which the vacuum layer (13) is at least partially filled with an insulating filler.

[0050] The insulating filler may be glass bubbles, perlite, multi-layer insulation (MLI), or any other suitable filler.

[0051] The use of glass bubbles further improves the insulation of the vacuum layer without breaking the vacuum.

[0052] According to one embodiment, a containment system (1) is provided, comprising heat exchange tubes (21) thermally connected to an inner barrier layer (11) and / or an outer barrier layer (12) made of ice.

[0053] The heat exchanger tubes may, for example, be embedded in the inner and / or outer barrier layers.

[0054] A heat exchanger tube can extend through the ice layer. A cooling fluid (refrigerant) can flow through the heat exchanger tube to provide a cooling load to the ice layer. The ice layer can be maintained at a storage temperature (T pres The storage temperature may be maintained at the ice layer's retention temperature (T hold ) higher. The heat exchanger tubes should also be ice-coated at T before filling the containment system to prevent thermal cracking. hold (or nearby) for cooling.

[0055] The heat exchanger tubes may be part of or connectable to a refrigeration cycle, as known to those skilled in the art, which includes a compressor, a condenser and an expander, with the heat exchanger tubes forming an evaporator.

[0056] According to one embodiment, a containment system (1) is provided, comprising reinforcement means (or reinforcements) embedded in or structurally connected to an inner barrier layer (11) and / or an outer barrier layer (12) made of ice.

[0057] The structural strength of these barrier layers is improved by having reinforcing means provided inside the ice layers. The reinforcing means may be formed by steel rods and / or heat exchanger tubes embedded in the inner and / or outer barrier layers. The structural rigidity may be improved by doped ICE. The ice may be doped with PTFE shavings / strands introduced during the construction phase of the inner and / or outer barrier layers.

[0058] According to one embodiment, there is provided a method of manufacturing a containment system according to the invention, the method comprising: a) providing a base floor element (102) having a plurality of spacer elements (14) protruding from a base layer at a protruding distance; b) forming a first portion of an outer barrier layer (12) on the base floor element (102) having a thickness less than the projection distance, the outer barrier layer having a first perimeter; c) forming a first portion of an inner barrier layer (11) supported by a plurality of spacer elements (14), the inner barrier layer having a second perimeter whereby, when viewed perpendicular to the plane of the base floor element, the second perimeter is entirely within the first perimeter; d) completing the inner barrier layer (11) by forming the remainder of the inner barrier layer in association with the first portion of the outer barrier layer (12) along the second outer periphery, the inner barrier layer (11) forming a containment space (2) for the liquid hydrogen (3); e) completing the outer barrier layer (12) by forming a remainder of the outer barrier layer in association with the first portion of the outer barrier layer along the first perimeter; f) filling the containment space (2) with liquid hydrogen (3), The outer barrier layer (12) is made of cryogenic ice having a temperature below -150°C.

[0059] This method provides an advantageous method of manufacturing a containment system because it uses a containment system made of a base floor element having a plurality of spacer elements, where the bottom of the outer barrier layer can be formed over the base floor element leaving the spacer elements extending over the bottom of the outer barrier layer, allowing the bottom of the inner barrier layer to be formed over the spacer elements.

[0060] The base floor element may be formed from any suitable material, such as concrete.

[0061] The base floor element may have a substantially upwardly facing wall element to allow easy formation of the bottom of the outer barrier layer.

[0062] Formation of the bottom portion of the inner barrier layer can be accomplished in different ways, such as using a temporary framework to allow for formation and placement of the bottom portion of the inner barrier layer.

[0063] The inner barrier layer may be made of ice and the outer barrier layer may be made of cryogenic ice, or both the inner and outer barrier layers may be made of cryogenic ice.

[0064] According to one embodiment, forming those parts of the inner and outer barrier layers made of ice. manufacturing a plurality of ice units (111); applying localized heating to predetermined surface areas of an ice unit (111) that is to be connected to another ice unit (111), thereby melting an outer layer of those predetermined surface areas; positioning interconnected ice units relative to one another and freezing the molten top layers of the surface areas together, thereby forming inner and outer barrier layers of ice.

[0065] Localized heating may be applied by using microwave or other handheld hot wire elements, a technique also called fusion by coagulation. [Brief description of the drawings]

[0066] [Figure 1] 1 illustrates a schematic side view of a storage system according to one embodiment. [Diagram 2] 13A and 13B show schematic side views of a storage system according to a further embodiment; [Figure 3a] 1 shows a schematic representation of a base element. [Figure 3b] 1A-1C are schematic cross-sectional side views of a partially formed containment system; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0067] 1 shows diagrammatically a containment system 1 for holding liquid hydrogen 3, such as liquid natural hydrogen, in a containment space 2. The containment system 1 comprises an inner barrier layer 11 and an outer layer 12. The inner layer 11 is the layer that is in direct contact with the liquid hydrogen 3, if present. The inner layer 11 is inside the outer layer 12.

[0068] Spacer elements 14 are provided to separate the inner barrier layer 11 from the outer barrier layer 12. According to an alternative embodiment described below with reference to Figures 3a and 3b, the spacer elements may alternatively protrude through the outer barrier layer 12 to support the inner barrier layer 11.

[0069] Between the inner barrier layer 11 and the outer barrier layer 12, a space is formed forming a vacuum layer 13. One or both of the inner barrier layer 11 and the outer barrier layer 12 may be formed from ice. The outer barrier layer is made of cryogenic ice.

[0070] The containment system 1 may include one or more additional insulation layers to further insulate the containment space 2. The containment system 1 may include one or more additional support layers to further strengthen the containment system 1. These additional insulation and support layers are not shown.

[0071] The vacuum layer 13 may be filled with a heat insulating filler, which is also not shown in FIG.

[0072] 2 shows an alternative embodiment in which the heat exchanger tubes 21 are embedded in the inner barrier layer 11 and the outer barrier layer 12. In this embodiment, the inner barrier layer 11 and the outer barrier layer 12 are preferably made of cryogenic ice. The heat exchanger tubes are connected to a cooling cycle (not shown) such that the heat exchanger tubes 21 can provide a cooling load to the inner barrier layer 11 and the outer barrier layer 12.

[0073] FIG. 2 further shows the ventilation inlet / outlet 31, fluid inlet / outlet, and vacuum outlet 51.

[0074] According to a further embodiment, the containment system comprises reinforcing means for adding structural stability to the inner barrier layer 11 and / or the outer barrier layer 12. The reinforcing means may for example be in the form of an independent structure made of steel, covered with ice. The reinforcing means may for example be formed by a skeleton on the inside of the inner barrier layer 11 and / or the outer barrier layer 12. The reinforcing means may also be partially provided on the outside of the inner barrier layer 11 and / or the outer barrier layer 12, but preferably not in contact with the containment space and the space for the vacuum layer 13.

[0075] 3a shows diagrammatically a base element 100 comprising a base floor element 102 having a number of spacer elements 14 protruding therefrom. The base element 100 further comprises an upstanding wall element 101 along the periphery of the base floor element 102 which defines the periphery of the outer barrier layer 12.

[0076] 3b shows diagrammatically a cross-sectional side view of the partially formed containment system. The bottom of the outer barrier layer 12 is formed on a base floor element 102 and the upstanding walls of the outer barrier layer 12 are formed against wall elements 101.

[0077] The bottom of the inner barrier layer 11 is formed and supported by spacer elements 14 .

[0078] In the embodiment shown in Figures 3A and 3B, both the inner barrier layer 11 and the outer barrier layer 12 are formed from cryogenic ice, however, as mentioned above, it will be appreciated that only one of the inner barrier layer 11 or the outer barrier layer 12 may be formed from (cryogenic) ice.

Claims

1. A containment system (1) for storing liquid hydrogen (3), said containment system (1) comprising one or more walls forming a containment space (2) for holding said liquid hydrogen (3), said containment space (2) containing said liquid hydrogen (3); At least one of the one or more walls comprises an inner barrier layer (11), an outer barrier layer (12), and one or more spacer elements (14) arranged between the inner barrier layer (11) and the outer barrier layer (12) to separate the inner barrier layer (11) and the outer barrier layer (12), thereby forming a space for a vacuum layer (13) between the inner barrier layer (11) and the outer barrier layer (12); the outer barrier layer (12) is made of cryogenic ice having a temperature below -150°C; The containment system (1), wherein the vacuum layer (13) has a pressure of less than 0.01 Pa.

2. The containment system (1) according to claim 1, wherein the inner barrier layer (11) is made of ice, preferably cryogenic ice having a temperature below -150°C.

3. 3. The containment system (1) according to claim 1 or 2, wherein the outer barrier layer (12) is covered on the outside by one or more additional insulating layers.

4. 3. The containment system (1) according to claim 1 or 2, wherein the vacuum layer (13) is at least partially filled with an insulating filler material.

5. 3. The containment system (1) according to claim 1 or 2, wherein the containment system (1) comprises heat exchange tubes (21) embedded in the inner barrier layer (11) and / or the outer barrier layer (12).

6. 3. The containment system (1) according to claim 1 or 2, wherein the containment system (1) comprises reinforcement means embedded in or structurally connected to the inner barrier layer (11) and / or the outer barrier layer (12).

7. 3. A method of manufacturing a containment system according to claim 1 or 2, said method comprising: a) providing a base floor element (102) having a plurality of spacer elements (14) protruding from said base layer at a protruding distance; b) forming a first portion of the outer barrier layer (12) on the base floor element (102) having a thickness less than the protrusion distance, the outer barrier layer having a first perimeter; c) forming a first portion of the inner barrier layer (11) supported by the plurality of spacer elements (14), the inner barrier layer having a second perimeter whereby, when viewed perpendicular to the plane of the base floor element, the second perimeter is entirely within the first perimeter; d) completing the inner barrier layer (11) by forming the remainder of the inner barrier layer in association with the first portion of the outer barrier layer (12) along the second periphery, the inner barrier layer (11) forming a containment space (2) for liquid hydrogen (3); e) completing the outer barrier layer (12) by forming a remainder of the outer barrier layer in association with the first portion of the outer barrier layer along the first periphery; f) filling said containment space (2) with liquid hydrogen (3), The outer barrier layer (12) is made of cryogenic ice having a temperature below -150°C. Law.

8. forming the ice portions of the inner and outer barrier layers; - Producing a plurality of ice units (111); applying localized heat to predetermined surface areas of the ice unit (111) that are connected to another ice unit (111), thereby melting said top layer of those surface areas; 8. The method of claim 7, wherein the method is carried out by positioning interconnected ice units relative to each other and allowing the melted top layers of the surface areas to freeze together, thereby forming the inner and outer barrier layers of ice.

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