STORAGE VESSEL AND CRYOGEN SUPPLY SYSTEM

Abstract

A storage vessel for storing a cryogen, having an inner vessel for receiving the cryogen, an outer vessel which surrounds the inner vessel, and a heating device, which is at least partially arranged within the inner vessel, for introducing heat into the cryogen, wherein the heating device has a heating element for generating the heat and an outer casing which fluid-tightly surrounds an interior space of the heating device, wherein the heating element is accommodated within the interior space, and wherein the heating element has a heating wire which is embedded in a metal oxide which is encapsulated by a casing accommodated within the interior space.

Claims

1. A storage vessel for storing a cryogen, having an inner vessel for receiving the cryogen, an outer vessel which surrounds the inner vessel, and a heating device, which is at least partially arranged within the inner vessel, for introducing heat into the cryogen, wherein the heating device has a heating element for generating the heat and an outer casing which fluid-tightly surrounds an interior space of the heating device, wherein the heating element is accommodated within the interior space, and wherein the heating element has a heating wire which is embedded in a metal oxide which is encapsulated by a casing accommodated within the interior space.

2. The storage vessel according to claim 1, wherein the interior space is filled with a heat-conducting medium.

3. The storage vessel according to claim 1, wherein the heating device is guided from a surroundings of the storage vessel through the outer vessel and the inner vessel into a liquid zone surrounded by the inner vessel.

4. The storage vessel according to claim 3, wherein the outer casing is guided through the outer vessel and the inner vessel and wherein the outer casing is connected to the outer vessel and the inner vessel in a material bond and/or form fit.

5. The storage vessel according to claim 3, wherein the outer casing has an end portion which projects into the surroundings and is closed fluid-tightly by means of a removable closure element, and wherein connecting lines of the heating element are led through the closure element.

6. The storage vessel according to claim 3, wherein the outer casing has a connection projecting into the surroundings and is in fluidic communication with the interior space, and wherein the connection is sealed fluid-tightly.

7. The storage vessel according to claim 1, wherein a heat transfer layer is provided on the outer casing and is attached to the outside of the outer casing.

8. The storage vessel according to claim 1, wherein the heating device has a support element which carries the heating element.

9. The storage vessel according to claim 8, wherein the support element has an outer side with a groove running helically around the support element, in which the heating element is accommodated at least in portions.

10. The storage vessel according to claim 8, wherein a gap is provided between the support element and the outer casing and runs circumferentially around the support element.

11. The storage vessel according to claim 8, wherein the support element is tubular and has a cylindrical inner sides.

12. The storage vessel according to claim 8, wherein the heating device has at least one temperature sensor which is arranged within the support element.

13. The storage vessel according to claim 12, wherein the heating device has a fastening element arranged within the support element for fastening the temperature sensor to the support element, and wherein the temperature sensor is inserted into the fastening element.

14. The storage vessel according to claim 13, wherein the fastening element is fluid-permeable.

15. A cryogen supply system for supplying a consumer with a cryogen, with at least one storage vessel according to claim 1.

Description

[0053] Further advantageous embodiments and aspects of the storage vessel and/or the cryogen supply system are the subject of the dependent claims and of the embodiments of the storage vessel and/or the cryogen supply system described below. The storage vessel and/or the cryogen supply system are explained below in more detail with reference to the accompanying figures based on preferred embodiments.

[0054] FIG. 1 shows a schematic sectional view of an embodiment of a storage vessel;

[0055] FIG. 2 shows the detailed view II according to FIG. 1; and

[0056] FIG. 3 shows a schematic sectional view according to the section line Ill-Ill in FIG. 2.

[0057] In the figures, the same or functionally equivalent elements have been provided with the same reference signs unless otherwise indicated.

[0058] FIG. 1 shows a schematic sectional view of an embodiment of a storage vessel 1. FIG. 2 shows the detailed view II according to FIG. 1. FIG. 3 shows a schematic sectional view according to the section line Ill-Ill in FIG. 2. In the following, reference is made simultaneously to FIGS. 1 through 3.

[0059] The storage vessel 1 can also be referred to as a storage tank. The storage vessel 1 is suitable for accommodating liquid hydrogen H2 (boiling point 1 bara: 20.268 K=252.882 C.). The storage vessel 1 can therefore also be referred to as a hydrogen storage vessel or as a hydrogen storage tank. However, the storage vessel 1 can also be used for other cryogenic liquids. Examples of cryogenic fluids or liquids, or cryogens for short, are liquid helium He in addition to the aforementioned liquid hydrogen H2 (boiling point 1 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: 90.18 K=182.97 C.).

[0060] The storage vessel 1 is suitable for use in or on a vehicle (not shown). The vehicle can be, for example, a maritime vessel, in particular a ship. The vehicle can be referred to as a maritime vehicle. In particular, the vehicle can be a maritime passenger ferry. Alternatively, the vehicle can also be a land vehicle. However, it is assumed below that the vehicle is a vessel.

[0061] The vehicle can have a consumer 2, in particular a fuel cell. In the present case, a fuel cell is understood to mean a galvanic cell that converts into electrical energy the chemical reaction energy of a continuously supplied fuel, in the present case hydrogen, and of an oxidant, in the present case oxygen. By means of the electrical energy obtained, an electric motor (not shown) can be powered, for example, which in turn drives a ship's propeller for propelling the vehicle. The storage vessel 1 is provided to supply the consumer 2 with hydrogen H2.

[0062] The storage vessel 1 can be part of a cryogen supply system 3 which is suitable for providing the consumer 2, which in the present case is preferably a fuel cell, with gaseous hydrogen H2 at a defined supply pressure and a defined supply temperature. For example, the hydrogen H2 is supplied to the consumer 2 in gaseous form at a supply pressure of, for example, 1 to 2.5 bara and a temperature of, for example, 0 to +70 C., in particular from +10 to +25 C. However, the supply pressure can also be up to 6 bara. The cryogen supply system 3 can be described as a hydrogen supply system. In addition to the storage vessel 1, the cryogen supply system 3 can comprise a vaporizer (not shown) which is suitable for vaporizing the liquid hydrogen H2 and supplying it to the consumer 2.

[0063] The storage vessel 1 is rotationally symmetrical with respect to a center axis or axis of symmetry 4. The axis of symmetry 4 can be oriented perpendicular to a direction of gravity g. This means that the storage vessel 1 is in a lying or horizontal position. Alternatively, the axis of symmetry 4 can be oriented parallel to the direction of gravity g. That is, the storage vessel 1 can also be positioned upright or vertically.

[0064] A coordinate system with a first spatial direction, length direction or x-direction x, a second spatial direction, height direction or y-direction y and a third spatial direction, depth direction or z-direction z is assigned to the storage vessel 1. The directions x, y, z are oriented perpendicularly to one another. The axis of symmetry 4 is placed parallel to the x-direction x. The storage vessel 1 is assigned a longitudinal direction L which can coincide with the x-direction x.

[0065] The storage vessel 1 comprises an outer vessel 5 which is rotationally symmetrical with respect to the axis of symmetry and an inner vessel 6 which is rotationally symmetrical with respect to the axis of symmetry 4. The inner vessel 6 is arranged completely inside the outer vessel 5. A vacuum space 7 is provided between the outer vessel 5 and the inner vessel 6, which is gap-shaped at least in portions. In the vacuum space 7, a negative pressure prevails compared to the surroundings 8 of the storage vessel 1. The surroundings 8 can also be referred to as the atmosphere. This means that the terms surroundings and atmosphere can be used interchangeably. An insulating element can be provided in the vacuum space 7, which at least partially or completely fills the vacuum space 7. The insulating element can have a multilayer insulation layer (MLI) or be designed as such. The outer vessel 5 and/or the inner vessel 6 can for example be made of stainless steel.

[0066] The outer vessel 5 comprises a tubular or cylindrical base section 9 which can have a rotationally symmetrical design in relation to the axis of symmetry 4. The base section 9 is closed at both end faces with the aid of a first cover section 10 and a second cover section 11. In cross section, the base section 9 can have a circular or approximately circular geometry. The cover sections 10, 11 are domed. The cover sections 10, 11 are domed in opposite directions so that the first cover section 10 and the second cover section 11 are domed outward in relation to the base section 9. The outer vessel 5 is fluid-tight, in particular gas-tight. The longitudinal direction L is oriented from the first cover section 10 towards the second cover section 11.

[0067] The inner vessel 6, like the outer vessel 5, comprises a tubular or cylindrical base section 12 which is rotationally symmetrical in relation to the axis of symmetry 4. The base section 12 is closed on both sides by a first cover section 13 and a second cover section 14. In cross section, the base section 12 can have a circular or approximately circular geometry. The cover sections 13, 14 are domed. In particular, the first cover section 13 and the second cover section 14 are domed in opposite directions so that the first cover section 13 and the second cover section 14 are domed outwards with respect to the base section 12. The outer vessel 6 is fluid-tight, in particular gas-tight. The outer vessel 5 and/or the inner vessel 6 can have a blow-off valve (not shown). The longitudinal direction L is oriented from the first cover section 13 towards the second cover section 14.

[0068] The liquid hydrogen H2 is accommodated in the inner vessel 6. The inner vessel 6 surrounds an interior space 15 in which the liquid hydrogen H2 is stored. As long as the hydrogen H2 is in the two-phase region, a gas zone 16 having vaporized hydrogen H2 and a liquid zone 17 having liquid hydrogen H2 can be provided in the inner vessel 6 or the interior space 15. After being filled into the inner vessel 6 or the interior space 15, the hydrogen H2 therefore has two phases having different aggregate states, namely liquid and gaseous. That is to say, in the inner vessel 6 or the interior space 15, there is a phase boundary 18 between the liquid hydrogen H2 and the gaseous hydrogen H2. The gas zone 16 and the liquid zone 17 together fill the interior space 15. The interior space 15 can be referred to as the vessel interior space.

[0069] The storage vessel 1 comprises a heating device 19. The heating device 19 is shown in sections in FIGS. 2 and 3. The heating device 19 is designed to introduce heat Q into the liquid hydrogen H2. The heating device 19 is operated electrically. Therefore, the heating device 19 can also be referred to as an electric heating device or as a heater, in particular as an electric heater. The heating device 19 projects through the first cover sections 10, 13 from the surroundings 8 into the inner vessel 6, in particular into the liquid zone 17. The part of the heating device 19 projecting into the inner vessel 6 or into the interior space 15 is preferably flushed by the liquid hydrogen H2 of the liquid zone 17.

[0070] The heating device 19 is rotationally symmetrical with respect to a center axis or axis of symmetry 20. The axis of symmetry 20 can be oriented parallel to the axis of symmetry 4. The axis of symmetry 20 is placed below the axis of symmetry 4 with respect to the y-direction y or the direction of gravity g. The heating device 19 is also assigned a radial direction R. The radial direction R is oriented to be perpendicular to the axis of symmetry 20 and away therefrom.

[0071] The heating device 19 comprises a fluid-tight outer casing 21. The outer casing 21 is tubular and can therefore also be referred to as an outer tube. The outer casing 21 is preferably made of a metal material, preferably of stainless steel. The outer casing 21 is preferably made of a material that conducts heat well. The outer casing 21 is guided through the first two cover sections 10, 13 into the liquid zone 17. This means that the outer casing 21 extends partially into the surroundings 8 and partially into the inner vessel 6, in particular into the liquid zone 17. The outer casing 21 can be soldered or welded into the first cover sections 10, 13. The outer casing 21 can also be made of a copper alloy, an aluminum alloy, glass, glass ceramic or ceramic.

[0072] The outer casing 21 is rotationally symmetrical in relation to axis of symmetry 20. The outer casing 21 can be circular in cross section. Alternatively, the outer casing 21 can also be slightly oval or elliptical in cross section. Viewed in a circumferential direction U, the outer casing 21 runs completely around the axis of symmetry 20. The outer casing 21 is therefore circumferentially closed. The circumferential direction U is oriented around the axis of symmetry 20 and along the outer casing 21. The outer casing 21 surrounds an interior space 22. The interior space 22 can be referred to as the interior space of the outer casing 21 or as the interior space of the heating device 19. The interior space 22 can also be referred to as the heating interior space. The interior space 22 is filled with a heat-conducting medium. The heat-conducting medium is preferably a gas, in particular helium He. The outer casing 21 is fluid-tight.

[0073] The outer casing 21 comprises a tubular base section 23 which is rotationally symmetrical with respect to the axis of symmetry 20. In addition to the base section 23, the outer casing 21 comprises a first end section 24 which projects into the surroundings 8 and is closed fluid-tight with the aid of a plate-shaped closure element 25. A second end section 26 is provided facing away from the first end section 24 and is lid-shaped and closes the base section 23 fluid-tightly at the front. The second end section 26 is placed within the liquid zone 17.

[0074] At least one heat transfer plate 27 can be provided on the outer casing 21, in particular on the base section 23, which extends in the radial direction R away from the base section 23. The heat transfer plate 27 serves to enlarge the surface so that the transfer of heat Q from the heating device 19 to the hydrogen H2 is improved. The heat transfer plate 27 is fin-shaped and can therefore also be referred to as a heat transfer fin. A plurality of heat transfer plates 27 can be provided.

[0075] Outside the outer vessel 5, the outer casing 21 has a connection 28 which can be closed fluid-tightly. With the help of the connection 28, for example, the interior space 22 can be filled with helium He. Furthermore, the connection 28 can also be used to monitor the heating device 19. For example, a pressure drop or pressure increase in the interior space 22 can be detected via the connection 28. The connection 28 is placed outside the storage vessel 1 in the surroundings 8.

[0076] In addition to the outer casing 21, the heating device 19 has a tubular support element 29 which carries a wire-shaped heating element 30. The support element 29 can also be called a support tube. The support element 29 is rotationally symmetrical in relation to axis of symmetry 20. The support element 29 is made of a material that conducts heat well. For example, the support element 29 is made of a metal material, in particular a copper alloy or an aluminum alloy. However, the support element 29 can also be made of glass, a glass ceramic or a ceramic.

[0077] The support element 29 can be an integral component, in particular a materially integral component. Integral or one-piece means that the support element 29 is a single component which is not composed of a plurality of subassemblies or components. In the present case, materially integral means in particular that the support element 29 is made entirely of the same material. Alternatively, the support element 29 can also be multi-part or multi-piece. In this case, the support element 29 is constructed from a plurality of subassemblies or components.

[0078] The support element 29 extends in the longitudinal direction L into the inner vessel 6. The support element 29 is preferably arranged completely within the outer vessel 5. Viewed in the circumferential direction U, the entire circumference of the support element 29 is closed. The support element 29 is accommodated in the outer casing 21. This means in particular that the support element 29 is placed in the interior space 22. Preferably, the support element 29 is placed centrally with respect to the axis of symmetry 20 so that in the circumferential direction U a gap 31 filled with helium He is provided which extends completely around the support element 29. The gap 31 can have a gap width of 0.5 to 1 millimeters. The gap width is selected to be as small as possible and as large as necessary to allow the support element 29 with the heating element 30 to be inserted into the outer casing 21. The gap 31 is part of the interior space 22. The gap 31 is optional. Alternatively, the support element 29 can rest on the inside of the outer casing 21. The heat transfer can thereby be improved.

[0079] A cylindrical outer side 32 of the support element 29 faces the outer casing 21. The gap 31 is provided between the outer side 32 and the outer casing 21. On the outer side 32, a groove 33 is provided which runs in the circumferential direction U in a helical or spiral manner around the support element 29 and accommodates the heating element 30. The heating element 30 is preferably a heating wire which is wound onto the support element 29. In the event that the support element 29 is made of an electrically conductive material, the heating element 30 can have an electrical insulation which electrically insulates the heating element 30 from the support element 29. For example, the above-mentioned heating wire can be embedded in magnesium oxide powder which is encapsulated by a non-current-conducting metallic casing, for example a stainless steel casing. In this case, the term heating element can therefore be understood to mean a metallic-mineral-insulated heating wire. The groove 33 is optional. The heating element 30 can also be wound onto the support element 29 without the groove 33.

[0080] A cylindrical inner side 34 of the support element 29 faces away from the outer side 32. The inner side 34 runs in the circumferential direction U around the axis of symmetry 20. The inner side 34 can be realized by a hole led through the center of the support element 29. The heating element 30 has electrical connection lines 35, 36 which are led through the closure element 25 to an open-loop and closed-loop control device 37. The open-loop and closed-loop control device 37 can supply current to the heating element 30 and therefore control an amount of heat Q introduced into the hydrogen H2. The open-loop and closed-loop control device 37 can be part of the storage vessel 1 and/or the cryogen supply system 3.

[0081] The heating device 19 has at least one temperature sensor 38 which is coupled to the open-loop and closed-loop control device 37 by means of a sensor line 39. The temperature of the heating device 19 can be detected with the aid of the temperature sensor 38. The temperature sensor 38 can be part of a control circuit comprising the heating element 30, the open-loop and closed-loop control device 37 and the temperature sensor 38. The temperature sensor 38 comprises a fastening tab 40. As an alternative to the fastening tab 40, it is also possible to provide other fastening types, for example clamping, screwing, soldering or plugging.

[0082] The temperature sensor 38 is held or fastened with the aid of a fastening element 41. The fastening element 41 is made of a material with good heat conduction, for example a copper alloy or an aluminum alloy. The fastening element 41 is tubular. The fastening element 41 is arranged within the support element 29. For example, the fastening element 41 is pressed into the support element 29. The fastening element 41 can be an integral component, in particular a materially integral component. Alternatively, the fastening element 41 can also be multi-part or multi-piece.

[0083] The fastening element 41 is rotationally symmetrical in relation to axis of symmetry 20. The fastening element 41 comprises a cylindrical outer side 42 which rests against the inner side 34 of the support element 29. The fastening element 41 further comprises a cylindrical inner side 43, which is realized, for example, by a hole provided centrally in the fastening element 41. The helium He can therefore flow through the fastening element 41.

[0084] For each temperature sensor 38, the fastening element 41 has a receiving hole 44 into which the respective temperature sensor 38 is inserted. The receiving hole 44 is provided in the front side of the fastening element 41 and extends along the longitudinal direction L or along the x-direction x into the fastening element 41. The receiving hole 44 runs parallel to the axis of symmetry 20. The receiving hole 44 can be a blind hole. Viewed along the radial direction R, the receiving hole 44 lies directly below the outer side 42.

[0085] A heat transfer layer 45 is provided on the outer casing 21 and is attached to the outside of the outer casing 21. The heat transfer layer 45 can be made of copper. Aluminum alloys are also possible as suitable materials for the heat transfer layer 45. The heat transfer layer 45 can be a copper sheet or a copper plate. For example, the heat transfer layer 45 is wound onto the outer casing 21. The heat transfer layer 45 can be materially bonded to the outer casing 21. For example, the heat transfer layer 45 is soldered onto the outer casing 21.

[0086] The heat transfer layer 45 can also only be wound onto the outer casing 21 and not materially bonded thereto, wherein two end sections 46, 47 of the heat transfer layer 45 are clamped or screwed together in order to connect the heat transfer layer 45 to the outer casing 21. A first end section 46 and a second end section 47 abut one another and are connected to one another. The heat transfer layer 45 ensures uniform heat transfer. The previously mentioned heat transfer plate 27 can be molded onto the heat transfer layer 45. In this case, the heat transfer plate 27 is formed by means of the two interconnected end sections 46, 47 of the heat transfer layer 45.

[0087] However, the heat transfer plate 27 can also be a separate component which is connected to the outer casing 21 or the heat transfer layer 45. A plurality of such heat transfer plates 27 can be provided on the outer casing 21 or on the heat transfer layer 45. The heat transfer plate 27 can be materially bonded to the outer casing 21 or the heat transfer layer 45. For example, the heat transfer plate 27 is soldered or welded to the outer casing 21 or the heat transfer layer 45.

[0088] The heat transfer plate 27 ensures that when the liquid level of the hydrogen H2 in the storage vessel 1 is low, at least the heat transfer plate 27 protrudes into the liquid zone 17 of the hydrogen H2, and heat Q can therefore be transferred to the hydrogen H2. Preferably, at least one heat transfer plate 27 is attached between the outer casing 21 and the inner vessel 6. Any number of heat transfer plates 27 can be provided. The heat transfer plate 27 is preferably made of a metal material with good heat conduction, such as a copper alloy or an aluminum alloy.

[0089] Although the present invention has been described with reference to exemplary embodiments, it can be modified in many ways within the scope of the claims.

REFERENCE SIGNS USED

[0090] 1 Storage vessel [0091] 2 Consumer [0092] 3 Cryogen supply system [0093] 4 Axis of symmetry [0094] 5 Outer vessel [0095] 6 Inner vessel [0096] 7 Vacuum space [0097] 8 Surroundings [0098] 9 Base section [0099] 10 Cover section [0100] 11 Cover section [0101] 12 Base section [0102] 13 Cover section [0103] 14 Cover section [0104] 15 Interior space [0105] 16 Gas zone [0106] 17 Liquid zone [0107] 18 Phase boundary [0108] 19 Heating device [0109] 20 Axis of symmetry [0110] 21 Outer casing [0111] 22 Interior space [0112] 23 Base section [0113] 24 End section [0114] 25 Closure element [0115] 26 End section [0116] 27 Heat transfer plate [0117] 28 Connection [0118] 29 Support element [0119] 30 Heating element [0120] 31 Gap [0121] 32 Outer side [0122] 33 Groove [0123] 34 Inner side [0124] 35 Connecting line [0125] 36 Connecting line [0126] 37 Open-loop and closed-loop control device [0127] 38 Temperature sensor [0128] 39 Sensor line [0129] 40 Fastening tab [0130] 41 Fastening element [0131] 42 Outer side [0132] 43 Inner side [0133] 44 Receiving hole [0134] 45 Heat transfer layer [0135] 46 End section [0136] 47 End section [0137] g Direction of gravity [0138] He Helium/medium [0139] H2 Hydrogen/cryogen [0140] L Longitudinal direction [0141] Q Heat [0142] R Radial direction [0143] U Circumferential direction [0144] x x direction [0145] y y direction [0146] z z direction