Storage vessel

Abstract

The invention relates to a storage vessel (1A, 1B) for storing a cryogen (H2), comprising an inner vessel (3) for containing the cryogen (H2), and an outer vessel (10) in which the inner vessel (3) is accommodated, wherein a gap (17) is provided between the inner vessel (3) and the outer vessel (10), and wherein the outer vessel (10) is made at least partially from a plastic film (14).

Description

[0001] Description

[0002] Storage container

[0003] The invention relates to a storage container for storing a cryogen. US 2012 / 279971 A1 forms the preamble of claim 1.

[0004] The object of the present invention is to provide a storage container that is improved compared to the prior art.

[0005] Accordingly, a storage container for storing a cryogen is proposed. The storage container comprises an inner container for receiving the cryogen and an outer container in which the inner container is received, wherein a gap is arranged between the inner container and the outer container, and wherein the outer container is made at least partially of a plastic film. According to the invention, the storage container has flexible retaining straps by means of which the outer container is connected to the inner container.

[0006] The advantage of using flexible retaining straps is that the outer container is fixed in its position relative to the inner container without the outer container exerting any significant tensile forces on the inner container, or vice versa. Because the outer container is at least partially made of a plastic film, it is possible to manufacture the storage container particularly cost-effectively. Furthermore, weight can be saved during the manufacturing process.

[0007] The cryogen is preferably hydrogen. The terms "cryogen" and "hydrogen" 1Therefore, they can be freely interchanged. In principle, however, the cryogen can also be any cryogen other than hydrogen. Examples of cryogenic fluids or liquids, or simply cryogens, include liquid helium, liquid nitrogen, or liquid oxygen, in addition to the aforementioned hydrogen. In this context, "cryogen" can refer to both the liquid and gaseous phases of the cryogen. The inner container is preferably cylindrical. However, the inner container can also be spherical. For the following, it is assumed that the inner container is cylindrical. The inner container can be rotationally symmetrical about a symmetry or central axis of the storage container. For this purpose, the inner container can, for example, have a tubular or hollow cylindrical base section, which is closed at its ends by two outwardly curved lid sections.The lid sections of the inner container can each have the shape of a hemispherical shell, a dished end, or a basket-arch base. The inner container preferably provides a gas zone containing the gaseous phase of the cryogen and a liquid zone containing the liquid phase of the cryogen. A phase boundary is provided between the gaseous and liquid phases. In other words, the cryogen exists in a two-phase state within the inner container. Supercritical media are also conceivable. The inner container is preferably pressurized.

[0008] The outer container is also preferably cylindrical. Alternatively, the outer container can also be spherical. The outer container encloses or completely encapsulates the inner container. The outer container can also have a tubular or hollow cylindrical base section, which is closed at its ends by two outwardly curved lid sections. The gap between the inner and outer containers is arranged such that the inner and outer containers preferably do not touch or contact each other. The gap can be pressurized with a vacuum. The outer container is preferably not pressure-bearing. The storage container is double-walled.

[0009] The outer container can be made entirely of plastic film. Alternatively, it can be made only partially of plastic film. In the latter case, the outer container can, for example, also be partially made of a metallic material. Suitable plastics for the film include polyethylene (PE) and polypropylene (PP). Other plastics can also be used. The plastic film is preferably white on the side facing the environment of the storage container. This reduces heat transfer into the storage container. In particular, the plastic film has an inner surface facing the gap and an outer surface facing away from the gap and towards the environment. At least the outer surface is preferably white. The plastic film can also be entirely white.

[0010] In this context, "plastic film" refers to a thin sheet of plastic. The plastic film can have a thickness ranging from a few millimeters to several millimeters. It can be manufactured in continuous rolls and then cut into suitable pieces to assemble the outer container. These pieces can be welded or glued together. Alternatively, the plastic film can be manufactured as a tubular film, which is then cut to size to form the outer container. The plastic film can be flexibly deformable.

[0011] According to one embodiment, the gap is filled with a thermal insulation material.

[0012] The thermal insulation material prevents heat from the surroundings of the storage container from entering the inner container and thus the cryogen. The thermal insulation material can be blown into the gap during the manufacturing of the storage container, for example. The gap is preferably completely filled with the thermal insulation material so that it completely surrounds or encloses the inner container. The inner container is thus encapsulated by the thermal insulation material. The thermal insulation material is positioned between the inner container and the outer container.

[0013] According to another embodiment, the gap is subjected to a vacuum, so that the thermal insulation material supports the outer container against the inner container.

[0014] In particular, the thermal insulation material is also subjected to a vacuum, causing it to compact. This insulation material then serves to support the outer container against the inner container. By applying a vacuum to the gap and using the insulation material to support the outer container against the inner container, it is reliably prevented that a gap forms between the insulation material and the inner container or between the insulation material and the outer container. Applying the vacuum to the gap allows the plastic film to deform, conforming to the shape of the insulation material. In this context, a "vacuum" is defined as a pressure of less than 300 mbar, preferably less than 10⁻⁶ mbar. 3 mbar, preferably less than 10' 7 mbar, to understand. The storage container is therefore vacuum-insulated or vacuum-damped.

[0015] According to another embodiment, the thermal insulation material is introduced into the gap as loose fill.

[0016] For example, the thermal insulation material could be perlite. However, it could also be glass wool or rock wool. The thermal insulation material could include cellulose. It could be in flake form. As mentioned earlier, the thermal insulation material could, for example, be blown into the gap during the manufacturing of the storage tank. In particular, this type of thermal insulation is known as blown-in insulation.

[0017] According to another embodiment, the flexible retaining straps connecting the outer container to the inner container are made of a plastic film. For example, the retaining straps can be bonded to the inner container and / or the outer container. Any number of retaining straps can be positioned one above the other along the central axis. The retaining straps are preferably long enough that, when the gap is filled with thermal insulation material, they form folds or waves, preventing the outer container from exerting any tensile forces on the inner container and vice versa.

[0018] According to another embodiment, the flexible retaining straps are arranged evenly distributed around a central axis of the storage container.

[0019] In particular, the retaining straps run along a radial direction of the storage container. This radial direction is perpendicular to and oriented away from the central axis. The flexible retaining straps can thus radiate outwards from the inner container towards the outer container. As mentioned previously, any number of retaining straps can be positioned one above the other along the central axis. The retaining straps prevent the outer container from tilting relative to the inner container when the gap is filled with thermal insulation material. The outer container can be suspended from the inner container by means of the retaining straps. According to a further embodiment, the storage container has a support structure connected to the inner container for supporting the storage container on a foundation, wherein the support structure passes through the outer container and is vacuum-tightly connected to it.Preferably, the outer container has vacuum-tight feedthrough flanges through which the support structure is guided through the outer container.

[0020] According to a further embodiment, the storage container has a support structure connected to the inner container for supporting the storage container on a foundation, wherein the outer container has vacuum-tight feedthrough flanges through which the support structure is guided through the outer container.

[0021] The support structure can, for example, have several support legs. For instance, the support structure may have three or four support legs. The support structure can also be a base frame. Preferably, the base frame is cylindrical. In the case of cylindrical inner containers, the base frame preferably has the same diameter as the hollow cylindrical base section. The support structure is rigidly connected to the inner container, for example, by welding. However, the outer container can move relative to the support structure, which is ensured by the vacuum-tight feedthrough flanges. Each support leg, as mentioned above, can be assigned such a vacuum-tight feedthrough flange. The foundation can, for example, be the deck of a watercraft. If the storage container is used for an immobile application, the foundation can, for example, be a concrete slab.

[0022] According to another embodiment, the storage container has a valve attached to the outer container for filling, emptying, venting and / or de-aerating the gap.

[0023] The valve allows the gap to be filled with thermal insulation material, for example. Conversely, the thermal insulation material can also be removed from the gap via the valve. Furthermore, the valve can be used to apply a vacuum to the gap or to vent the gap to break the vacuum. According to another embodiment, the outer container has a base section made of a metallic material and a plastic film connected to this base section. In other words, the metallic base section forms a first, lower outer container section, to which an upper, second outer container section made of the plastic film is attached.

[0024] In the case of a cylindrical outer container, the metallic bottom section preferably extends to the hollow cylindrical base section. This means that the metallic bottom section preferably replaces one of the previously mentioned lid sections made of plastic film, in this case, the lower lid section. The bottom section is preferably convex and can have the shape of a hemispherical shell, a dished end, or a basket-arch bottom.

[0025] In the case of a spherical outer container, the bottom section preferably forms a hemispherical shell, i.e., the bottom section forms an opening angle of 180°.

[0026] Alternatively, bottom sections are also conceivable that are spherical segment shells smaller than hemispherical shells. The opening angle of the spherical segment shell is preferably 60° to 180°, particularly preferably 110° to 130°. The opening angle is measured as the smaller of two angles between two lines that lie in a common plane with the center of the spherical segment shell, each passing through the center of the spherical segment shell and being tangent to the spherical segment shell.

[0027] In the embodiment described above, the outer container is therefore not made entirely of the plastic film, but only partially. The aforementioned support structure passes through the bottom section. The bottom section preferably has an interface circumferential around the central axis, at which the plastic film is connected to the bottom section.

[0028] For example, the plastic film may be glued to the floor section. The plastic film may also be vulcanized to the floor section.

[0029] According to another embodiment, the inner container is spherical or cylindrical. If the inner container is spherical, the outer container is also preferably spherical. If the inner container is cylindrical, the outer container is also preferably cylindrical.

[0030] The term "one" here should not necessarily be understood as restricting the count to exactly one element. Rather, it can also refer to multiple elements, such as two, three, or more. Similarly, every other counter used here should not be interpreted as requiring a precise restriction to exactly the corresponding number of elements. Rather, numerical deviations, both higher and lower, are possible.

[0031] Other possible implementations of the storage container also include combinations of features or embodiments described previously or subsequently with regard to the exemplary embodiments, even if not explicitly mentioned. In such cases, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the storage container.

[0032] Further advantageous embodiments of the storage container are the subject of the dependent claims and the exemplary embodiments of the storage container described below. The storage container is further explained below with reference to preferred embodiments and the accompanying figures.

[0033] Fig. 1 shows a schematic sectional view of an embodiment of a storage container;

[0034] Fig. 2 shows the detail view II according to Fig. 1; and

[0035] Fig. 3 shows a schematic sectional view of another embodiment of a storage container.

[0036] In the figures, identical or functionally equivalent elements have been designated with the same reference numerals unless otherwise indicated. Fig. 1 shows a schematic sectional view of an embodiment of a storage container 1A. Fig. 2 shows the detailed view II according to Fig. 1. Reference is made hereafter to Figs. 1 and 2 simultaneously.

[0037] Storage container 1A can also be referred to as a storage tank. Storage container 1A is preferably suited for storing hydrogen (H₂) (boiling point 1 bara: 2.68 K = -252.882 °C). Therefore, storage container 1A can also be referred to as a hydrogen storage container or hydrogen storage tank. However, storage container 1A can also be used for other cryogenic liquids. Examples of cryogenic fluids or liquids, or simply cryogens, include, in addition to the aforementioned hydrogen (H₂), liquid helium (He) (boiling point 2 bara: 4.222 K = -268.928 °C), liquid nitrogen (N₂) (boiling point 1 bara: 77.35 K = -195.80 °C), or liquid oxygen (O₂) (boiling point 1 bara: 9.18 K = -182.97 °C). In the following, it is assumed that hydrogen (H₂) is used as the cryogen. Accordingly, the terms "hydrogen" and "cryogen" can be freely interchanged in the present case.

[0038] The storage container 1A can be a transport container. For example, liquid hydrogen (LH2) can be transported using the storage container 1A. The storage container 1A can be part of a vehicle, particularly a watercraft. In this case, the storage container 1A is suitable for mobile applications. However, the storage container 1A can also be used in stationary applications, such as in building technology.

[0039] The storage container 1A is rotationally symmetrical about a symmetry or central axis 2. The central axis 2 is oriented parallel to a gravitational direction g. This means, in particular, that the storage container 1A is positioned upright. However, the storage container 1A can also be arranged horizontally. In this case, the central axis 2 is oriented perpendicular to the gravitational direction g. The storage container 1A also has a radial direction R. The radial direction R is oriented perpendicular to the central axis 2 and points away from it.

[0040] The storage container 1A comprises an inner container 3, which is also rotationally symmetrical about the central axis 2. The inner container 3 comprises a tubular or cylindrical base section 4, which is also rotationally symmetrical about the central axis 2. The base section 4 can have a circular or nearly circular cross-section. The base section 4 is connected at both ends by means of a cover section 5, 6. The cover sections 5, 6 are convex. A first cover section 5 and a second cover section 6 are convex in opposite directions, so that the cover sections 5, 6 are convex outwards with respect to the base section 4. The inner container 3 is fluid-tight, in particular gas-tight. The inner container 3 is made of stainless steel. Alternatively, the inner container 3 can also be spherical.

[0041] The inner container 3 holds liquid hydrogen LH2. As long as the hydrogen H2 is in the two-phase region, the inner container 3 can contain a gas zone 7 with gaseous hydrogen GH2 and a liquid zone 8 with liquid hydrogen LH2. Therefore, after being filled into the inner container 3, the hydrogen H2 can exist in two phases with different states of matter, namely liquid and gaseous. This means that there is a phase boundary 9 in the inner container 3 between the liquid hydrogen LH2 and the gaseous hydrogen GH2.

[0042] The gaseous hydrogen GH2 can also be referred to as the gaseous phase. Accordingly, the terms "gaseous hydrogen" and "gaseous phase" can be used interchangeably. The liquid hydrogen LH2 can also be referred to as the "liquid phase." Accordingly, the terms "liquid hydrogen" and "liquid phase" can be used interchangeably.

[0043] The inner container 3 is completely enclosed within an outer container 10. The storage container 1A is therefore double-walled. The inner container 3 is completely enclosed or encapsulated by the outer container 10. The outer container 10 is also rotationally symmetrical about the central axis 2. Like the inner container 3, the outer container 10 comprises a tubular or cylindrical base section 11, which is also rotationally symmetrical about the central axis 2. The base section 11 can have a circular or nearly circular cross-section.

[0044] The base section 11 is closed at each end by a cover section 12, 13. In particular, a first cover section 12 and a second cover section 13 are provided. The cover sections 12, 13 are convex in opposite directions, so that the cover sections 12, 13 are convex outwards with respect to the base section 11. The outer container 10 is fluid-tight, in particular gas-tight.

[0045] As shown in Fig. 2, the outer container 10, unlike the inner container 3, is not made of a metallic material but of a plastic material. In particular, the outer container 10 is made of a plastic film 14. Suitable plastics include, for example, polyethylene (PE) or the like. Facing the environment 15 of the storage container 1A, the plastic film 14 used for the outer container 10 preferably has an outer surface 16 that is colored white. Alternatively, the plastic film 14 can also be colored white throughout. A gap 17 is arranged between the inner container 3 and the outer container 10. The plastic film 14 has an inner surface 18 facing the gap 17 and thus away from the outer surface 16.

[0046] Returning to Fig. 1, a valve 19 is attached to the top of the outer container 10 in the orientation shown in Fig. 1. The gap 17 between the inner container 3 and the outer container 10 can be vented and aerated, for example, by means of the valve 19. The gap 17 is designed such that the inner container 3 and the outer container 10 do not contact each other.

[0047] The gap 17 is completely filled with a thermal insulation material 20. The thermal insulation material 20 is introduced into the gap 17, for example, through the valve 19 as bulk material, to completely fill the gap 17 with the thermal insulation material 20. After the gap 17 is filled with the thermal insulation material 20, a vacuum is applied to the gap 17. This can be done using the valve 19. A "vacuum" in this context refers in particular to a pressure of less than 300 mbar, preferably less than 10⁻⁶ mbar. 3 mbar, preferably less than 10' 7mbar, to understand. When a vacuum is applied to the gap 17, the thermal insulation material 20 supports the outer container 10 against the inner container 3.

[0048] The outer container 10 is connected to the inner container 3 by means of a plurality of flexibly deformable retaining straps 21, of which only one is provided with a reference numeral in Fig. 1. The retaining straps 21 are preferably also made of a plastic film. The retaining straps 21 can, for example, be bonded to the inner container 3. The retaining straps 21 can also be bonded to the outer container 10. The retaining straps 21 make it possible to attach the outer container 10 to the inner container 3 without the outer container 10 exerting any relevant tensile forces on the inner container and vice versa. In addition, the retaining straps 21 prevent the outer container 10 from tilting relative to the inner container 3 when the gap 17 is filled with the thermal insulation material 20.

[0049] The retaining straps 21 extend along the radial direction R from the inner container 3 towards the outer container 10. The retaining straps 21 can be arranged evenly distributed around the central axis 2. Any number of retaining straps 21 can be provided along the central axis 2. The retaining straps 21 can connect the base sections 4, 11 as well as the cover sections 5, 12 and the cover sections 6, 13 to each other. The retaining straps 21 are preferably loose, so that the retaining straps 21 may exhibit folds or waves when the gap 17 is filled.

[0050] Storage tank 1A can be placed on foundation 22. The foundation

[0051] 22 could, for example, be the deck of a watercraft. If the storage tank 1A is used for a stationary application, the foundation 22 could also be, for example, a concrete slab. To support the storage tank 1A against the foundation 22, the storage tank 1A has a support structure.

[0052] 23, with the help of which the storage tank 1A is supported on the foundation 22.

[0053] The support structure 23 has several, for example three, support legs 24, 25, which are firmly connected to the inner container 3, in particular to the second lid section 6 of the inner container 3. For example, the support legs 24, 25 can be welded to the second lid section 6. The support structure 23, in particular the support legs 24, 25, extend through the outer container 10. For this purpose, the outer container 10 has vacuum-tight feedthrough flanges 26, 27. Each support leg 24, 25 is associated with such a feedthrough flange 26, 27.

[0054] Fig. 3 shows a schematic sectional view of another embodiment of a storage container 1 B. The storage container 1B according to Fig. 3 differs from the storage container 1A according to Figs. 1 and 2 only in that the storage container 1B has an outer container 10 made of a plastic film 14 as mentioned above, which has only a cylindrical base section 11 and a first lid section 12 closing the end face of the base section 11.

[0055] The outer container 10 does not have a second, lower lid section 13 made of plastic film 14 as mentioned previously. Instead, the outer container 10 comprises a bottom section 28 made of a metallic material, such as a stainless steel alloy. In other words, the bottom section 28 forms a first, lower outer container section 28, to which an upper, second outer container section is attached in the form of the base section 11 and the lid section 12, which are made of plastic film. In the cylindrical outer container 10 shown in Fig. 3, the bottom section 28 preferably extends to the hollow cylindrical base section 11. The bottom section 28 is convex. Unlike the hemispherical shell shown in Fig. 3, the bottom section can have the shape of a dished end or basket-arch end.

[0056] A support structure 23, as previously mentioned, passes through the bottom section 28 by means of feedthrough flanges 26, 27. Alternatively, the support structure 23 can also be rigidly connected to the bottom section 28. The base section 11 of the outer container 10 is connected to the bottom section 28 at an interface 29 that extends around the central axis 2. The interface 29 can, for example, be an adhesive bond or the like.

[0057] Although the present invention has been described using exemplary embodiments, it can be modified in many ways. Reference symbols used

[0058] 1A storage container

[0059] 1 B Storage container

[0060] 2 Central axis

[0061] 3 inner containers

[0062] 4 Basic section

[0063] 5 Cover section

[0064] 6 Cover section

[0065] 7 Gas Zone

[0066] 8 Liquid zone

[0067] 9 Phase boundary

[0068] 10 external containers

[0069] 11 Basic section

[0070] 12 Cover section

[0071] 13 Cover section

[0072] 14 plastic film

[0073] 15 surroundings

[0074] 16 outdoor area

[0075] 17 gaps

[0076] 18 interior surface

[0077] 19 valve

[0078] 20 Thermal insulation material

[0079] 21 Retaining strap

[0080] 22 Foundation

[0081] 23 Support structure

[0082] 24 Support leg

[0083] 25 Support leg

[0084] 26 Feedthrough flange

[0085] 27 Feedthrough flange

[0086] 28 floor section

[0087] 29 Interface g Gravity direction

[0088] GH2 gaseous hydrogen / gaseous phase LH2 liquid hydrogen / liquid phase

[0089] R Radial direction

Claims

Patent claims 1. Storage container (1A, 1B) for storing a cryogen (H2), comprising an inner container (3) for receiving the cryogen (H2), and an outer container (10) in which the inner container (3) is received, wherein a gap (17) is arranged between the inner container (3) and the outer container (10), and wherein the outer container (10) is made at least partially of a plastic film (14), characterized in that the storage container (1A, 1B) has flexible retaining straps (21) by means of which the outer container (10) is connected to the inner container (3).

2. Storage container according to claim 1, wherein the gap (17) is filled with a thermal insulation material (20).

3. Storage container according to claim 2, wherein the gap (17) is subjected to a vacuum, so that the thermal insulation material (20) supports the outer container (10) against the inner container (3).

4. Storage container according to claim 2 or 3, wherein the thermal insulation material (20) is introduced into the gap (17) as bulk material.

5. Storage container according to one of claims 1 - 4, wherein the flexible retaining straps (21) are made of a plastic film.

6. Storage container according to one of claims 1 - 5, wherein the flexible retaining straps (21) are arranged evenly distributed around a central axis (2) of the storage container (1A, 1B).

7. Storage container according to one of claims 1 - 6, comprising a support structure (23) connected to the inner container (3) for supporting the storage container (1A, 1B) on a foundation (22), wherein the support structure (23) is passed through the outer container (10) and is vacuum-tight connected to the outer container (10).

8. Storage container according to one of claims 1 - 7, wherein the outer container (10) has vacuum-tight feedthrough flanges (26, 27) through which the support structure (23) is guided through the outer container (10).

9. Storage container according to one of claims 1 - 8, comprising a valve (19) attached to the outer container (10) for filling, emptying, venting and / or de-aerating the gap (17).

10. Storage container according to one of claims 1 - 9, wherein the inner container (3) is spherical or cylindrical.

11. Storage container according to one of claims 1 - 10, wherein the inner container (3) has a hollow cylindrical base section (11) and two outwardly curved lid sections, each in the form of a dished bottom or a basket-arch bottom.

12. Storage container according to one of claims 1 - 11, wherein the outer container (10) has a bottom section (28) made of a metallic material and the plastic film (14) which is connected to the bottom section (28).

13. Storage container according to claim 12, wherein the bottom section (28) has the shape of a dished end, a basket-arch bottom or a hemispherical shell.

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