Storage container and method

Abstract

A storage container (1) for storing a cryogen (H2), comprising an inner container (3) for receiving the cryogen (H2), and a withdrawal apparatus (16) for withdrawing a liquid phase (LH2) of the cryogen (H2) from the inner container (3), wherein the withdrawal apparatus (16) comprises a withdrawal line (17) which is fluidically connected to the inner container (3), an inner barrier (21) in which the withdrawal line (17) is at least partially accommodated, an outer barrier (30) in which the inner barrier (21) is at least partially accommodated, and a leakage detection device (28) which is configured to detect, on the basis of a pressure change within an inner volume (23) enclosed by the inner barrier (21) and / or on the basis of a pressure change within an outer volume (32) enclosed by the outer barrier (30), whether the withdrawal line (17), the inner barrier (21) and / or the outer barrier (30) has a leak. The inner volume (23) is filled with a detection gas (He), wherein the detection gas (He) has an overpressure relative to the outer volume (32).

Description

[0001] Description

[0002] Storage tanks and processes

[0003] The invention relates to a storage container for storing a cryogen and a method for detecting a leak in such a storage container.

[0004] According to internal company knowledge, storage tanks for liquid hydrogen have an inner tank in which the liquid hydrogen is held, and an outer tank in which the inner tank is arranged. A multi-layer thermal insulation element is arranged between the inner and outer tanks. To remove liquid hydrogen, a removal line opens out of the bottom of the inner tank for removing the liquid hydrogen from the inner tank. To remove gaseous hydrogen, a removal line opens out of the top of the inner tank for removing the gaseous hydrogen from the inner tank. The removal line runs through the outer tank. A valve, in particular a shut-off valve, is connected to the removal line.

[0005] The most critical point for leaks is the extraction line upstream of the valve. If a leak occurs in this area of ​​the extraction line, it can cause the entire storage vessel to empty. This can cause the hydrogen to come into contact with the thermal insulation element and damage it. The outer vessel cools down to such an extent that air components condense on it. These condensed air components drip into a drip tray located below the storage vessel and evaporate. This continues until all of the liquid hydrogen, which can have a mass of several tons, evaporates and is vented through the storage vessel's emergency relief valves. If the storage vessel has a foundation that cannot withstand cryogenic temperatures, it will be cooled well beyond its design temperature and destroyed.This is especially true when carbon steels, often used in shipbuilding, are used as foundation materials. This needs to be improved. DE 103 35245 A1 concerns a cryogenic tank system for a motor vehicle. The system has one or more test layers with test devices for monitoring the pressure within each test layer. This allows leaks or failure of the cryogenic tank system to be detected.

[0006] Against this background, it is an object of the present invention to provide an improved storage container.

[0007] Accordingly, a storage container for storing a cryogen is proposed.The storage container comprises an inner container for receiving the cryogen and a removal device for removing the cryogen from the inner container, wherein the removal device has: a removal line which is in fluid communication with the inner container, an inner barrier in which the removal line is at least partially received and which encloses an inner volume, an outer barrier in which the inner barrier is at least partially received and which encloses an outer volume, wherein the inner volume is filled with a detection gas, and wherein the detection gas has an overpressure compared to the outer volume, and a leakage detection device which is configured to detect, based on a pressure change within the inner volume and / or based on a pressure change within the outer volume, whether the removal line, the inner barrier and / or the outer barrier has a leak.

[0008] Because the sampling line is housed in the inner barrier, if the sampling line leaks, the cryogen flows into the inner barrier and is contained. This prevents the cryogen from penetrating the outer volume. Because the sampling device features a leak detection system, it is possible to detect early on whether the sampling line, the inner barrier, and / or the outer barrier are damaged.

[0009] The cryogen can be hydrogen. Therefore, the term "cryogen" can be exchanged for "hydrogen" and vice versa. However, the cryogen can also be helium or the like. The storage container can also be referred to as a hydrogen storage container. Preferably, the storage container contains a gas zone filled with a gaseous phase of the cryogen and a liquid zone filled with the liquid phase of the cryogen. A phase boundary is provided between the gas zone and the liquid zone. The gas zone is characterized in particular by the fact that it can accommodate the gaseous phase. The liquid zone is characterized in particular by the fact that it can accommodate the liquid phase. Accordingly, the liquid phase of the cryogen is located in the liquid zone within the storage container. Accordingly, the gaseous phase of the cryogen is located in the gas zone.The phase boundary separates the gaseous phase from the liquid phase. The gaseous phase is located above the liquid phase, viewed along the direction of gravity. The withdrawal device can be used to withdraw the liquid phase, the gaseous phase, or both phases from the storage vessel. The cryogen preferably has a pressure of 2 to 20 bara, particularly preferably 2 to 17 bara.

[0010] The liquid phase is preferably liquid hydrogen. Accordingly, the term "liquid phase" can be replaced with the term "liquid hydrogen" and vice versa. The gaseous phase is preferably gaseous hydrogen. Accordingly, the term "gaseous phase" can be replaced with the term "gaseous hydrogen" and vice versa.

[0011] The withdrawal device is preferably provided on the underside of the inner container, with the withdrawal line discharging from the liquid zone and / or gas zone. Alternatively, the withdrawal device can be provided on the top of the inner container, with the withdrawal line discharging from the gas zone. Due to its hydrostatic pressure, the liquid phase flows from the liquid zone into the withdrawal line. The term "fluidly connected" to the inner container is understood here to mean, in particular, that the liquid and / or gaseous phase can flow from the inner container, in particular from the liquid zone or the gas zone, into the withdrawal line.

[0012] The inner barrier is preferably tubular. The inner barrier follows the course of the extraction line. The extraction line is enclosed or encapsulated by the inner barrier. However, this does not preclude the extraction line from protruding from the inner barrier. The outer barrier is preferably also tubular. The inner barrier runs through the outer barrier, with the extraction line running through the inner barrier. This results in a three-layer structure of the extraction device, with the three-layer structure comprising the extraction line, the inner barrier, and the outer barrier. The inner barrier is enclosed or encapsulated by the outer barrier, at least in sections. However, this does not preclude the inner barrier from protruding from the outer barrier.

[0013] The inner barrier encloses the inner volume. The outer barrier encloses the outer volume. The inner volume is arranged at least partially within the outer volume. The outer volume thus encloses the inner volume at least partially. The inner volume is preferably gas-filled. The inner volume can be filled with a detection gas, for example, in the form of helium. The outer barrier is preferably subjected to a vacuum.

[0014] Depending on whether the sampling line, the inner barrier, and / or the outer barrier is leaking, a pressure change occurs within the inner volume and / or within the outer volume. Depending on whether there is only a pressure change in the inner volume or also a pressure change in both the inner volume and the outer volume, the leak detection device can detect or record the exact location of the leak. Accordingly, "detecting" in this case is understood in particular to mean that the leak detection device can, for example, provide information based on the pressure change(s) as to whether the sampling line, the inner barrier, and / or the outer barrier is leaking.

[0015] A "pressure change" in this context can be understood as either an increase or a rise in pressure or a decrease or a drop in pressure in the inner volume and / or in the outer volume. A "leakage" in this context can be understood as an opening, crack, rupture, or the like in the sampling line, the inner barrier, and / or the outer barrier. For example, a leak in the inner barrier causes the inner volume to be brought into fluid communication with the outer volume.

[0016] According to one embodiment, the storage container comprises an outer container enclosing the inner container, wherein a gap is provided between the inner container and the outer container, wherein the gap is subjected to a vacuum, and wherein the outer volume is in fluid communication with the gap.

[0017] The inner container is thus arranged within the outer container. The outer container encapsulates the inner container. The gap and the outer volume form a common gas space, which is subjected to a vacuum. A "vacuum" in this case is defined in particular as a pressure of less than 300 mbar, preferably less than 10' 3 mbar, more preferably less than 10' 7 mbar. The storage tank is thus vacuum-insulated. The vacuum created in the gap and the outer volume serves as thermal insulation.

[0018] According to a further embodiment, the outer barrier is connected to the outer container in a gas-tight manner.

[0019] For example, the outer barrier can be firmly bonded to the outer container. In bonded connections, the connecting partners are held together by atomic or molecular forces. Bonded connections are non-detachable connections that can only be separated by destroying the connecting elements and / or the connecting partners. For example, the outer barrier is welded or soldered into the outer container. The outer barrier preferably does not contact the inner container. In particular, the outer barrier opens out of the gap provided between the inner and outer containers.

[0020] According to a further embodiment, the inner barrier is connected to the inner container in a gas-tight manner. For example, the inner barrier can be integrally connected to the inner container. The inner barrier can be welded or soldered into the inner container. The inner barrier is preferably passed through the outer container without contacting it.

[0021] According to a further embodiment, the leakage detection device comprises an inner pressure sensor for detecting a pressure change in the inner volume and an outer pressure sensor for detecting a pressure change in the outer volume.

[0022] The outer pressure sensor can be arranged on the outer barrier or on the outer container. Multiple outer pressure sensors can be provided. The inner pressure sensor is arranged, in particular, on the inner barrier. Multiple inner pressure sensors can be provided. The inner pressure sensor can be operatively connected to the inner volume by means of an inner pressure sensor line. The outer pressure sensor can be operatively connected to the outer volume by means of an outer pressure sensor line.

[0023] According to a further embodiment, the leak detection device has an internal overpressure protection device for protecting the inner barrier against overpressure and an external overpressure protection device for protecting the outer barrier against overpressure.

[0024] The overpressure protection devices can be designed as bursting discs, for example. The inner overpressure protection device is designed to open the inner volume to the environment of the storage container when a defined overpressure is reached. Accordingly, the outer overpressure protection device is suitable for opening the outer volume to the environment when a defined overpressure is reached. The overpressure protection devices can each have a sensor system that sends a sensor signal to an evaluation unit of the leak detection device when the inner overpressure protection device and / or the outer overpressure protection device is triggered. In other words, the evaluation unit can detect a triggering of the inner overpressure protection device and / or a triggering of the outer overpressure protection device.Triggering the overpressure protection devices can be used to detect or record leaks in the sampling line, the inner barrier and / or the outer barrier.

[0025] According to a further embodiment, the leakage detection device has an evaluation unit which is operatively connected to the inner pressure sensor and to the outer pressure sensor and which detects a leak in the extraction line when there is a pressure equalization between the extraction line and the inner volume and at the same time there is no pressure change in the outer volume, which detects a leak in the inner barrier when there is a pressure drop in the inner volume and at the same time there is a pressure increase in the outer volume and / or which detects a leak in the outer barrier when there is a pressure increase in the inner volume and at the same time there is a pressure increase in the outer volume.

[0026] The internal overpressure protection and / or the external overpressure protection can also be operatively connected to the evaluation unit. The evaluation unit can therefore also use the triggering of the overpressure protection to detect a leak. If there is a leak in the sampling line, the liquid and / or gaseous phase of the cryogen escapes from the sampling line and into the inner volume. This results in pressure equalization between the sampling line and the inner volume. The outer volume is not affected. Therefore, there is no pressure change in the outer volume. From these pressure conditions, it can be concluded that a leak can only exist in the sampling line. If there is a leak in the inner barrier, the detection gas flows from the inner volume into the outer volume subjected to vacuum.This means that there is a pressure drop in the inner volume and a simultaneous pressure increase in the outer volume because the vacuum in the outer volume collapses. Based on these pressure conditions, it can be concluded that the inner barrier is damaged. If there is a leak in the outer barrier, the vacuum in the outer volume collapses, resulting in a pressure increase in the outer volume. Due to the loss of vacuum in the outer volume, the thermal insulation effect of the vacuum is lost and heat is introduced into the inner barrier and thus into the inner volume, resulting in the previously mentioned pressure increase in the inner volume. From this, it can be concluded that only the outer barrier is damaged. Based on the pressure conditions, it is therefore possible to easily and reliably determine whether the sampling line, the inner barrier and / or the outer barrier is leaking.

[0027] According to the invention, the inner volume is filled with a detection gas, wherein the detection gas has an overpressure relative to the outer volume. During the withdrawal of cryogen via the withdrawal line, the detection gas preferably has an overpressure or differential pressure relative to the outer volume of 0.3 to 4 bara, particularly preferably 0.3 to 1 bara.

[0028] For example, the detection gas is helium. However, the detection gas can also be argon or another, preferably inert, gas that remains in the gaseous state during the withdrawal of cryogen via the withdrawal line, i.e., does not condense. The detection gas can also be a mixture of the aforementioned gases.

[0029] The detection gas is introduced into the inner volume at a temperature and pressure which ensure that when cryogen is withdrawn via the withdrawal line, the detection gas cools down and loses pressure, the detection gas maintains an overpressure or differential pressure compared to the outer volume, preferably corresponding to the pressure ranges mentioned above. At the same time, the detection gas in the inner volume should maintain a negative pressure or differential pressure compared to the cryogen in the withdrawal line. In other words, this means that the detection gas is introduced into the inner volume or is present in the inner volume at a pressure and temperature which ensure that when cryogen is withdrawn via the withdrawal line, the pressure of the detection gas is greater than the pressure prevailing in the outer volume. Preferably, the detection gas is introduced into the inner volume oris present in the inner volume at a pressure and temperature that ensure that when cryogen is withdrawn via the withdrawal line, the pressure of the detection gas is lower than the pressure of the cryogen in the withdrawal line. The pressure difference between the cryogen in the withdrawal line and the detection gas in the inner volume is preferably at least 0.3 bara, particularly preferably at least 1 bara. The pressure difference or overpressure between the detection gas in the inner volume and the pressure prevailing in the outer volume is preferably at least 0.3 bara, particularly preferably at least 1 bara.

[0030] According to a further embodiment, the extraction device has a valve box which encloses a receiving space in which a valve connected to the extraction line is accommodated.

[0031] The valve box can also be referred to as a valve box. The valve box is preferably vacuum-insulated. A variety of different valves can be arranged within the valve box.

[0032] According to a further embodiment, the outer barrier is connected gas-tight to the valve box, wherein the outer volume is fluidically separated from the receiving space.

[0033] For example, the outer barrier is integrally bonded to the valve box. The outer barrier can be welded or soldered to the valve box.

[0034] In particular, the outer barrier can be connected in a gas-tight manner to a wall of the valve box. This wall fluidically separates the outer volume from the receiving space.

[0035] According to a further embodiment, the inner barrier ends within the receiving space, wherein the inner volume is fluidically separated from the receiving space.

[0036] The inner barrier extends into the receiving chamber. However, the inner barrier is sealed gas-tight from the receiving chamber.

[0037] According to a further embodiment, the inner barrier encloses the valve in a gas-tight manner.

[0038] For this purpose, the inner barrier can have a receiving section for accommodating the valve. The valve can have an actuating element that extends gas-tight from the aforementioned receiving section of the inner barrier and from the valve box. The actuating element can be wave-shaped or rod-shaped. The actuating element can be driven by a drive element, for example, in the form of an electric motor.

[0039] According to a further embodiment, the inner container and / or the inner barrier are enclosed by a thermal insulation element.

[0040] The thermal insulation element is multi-layered. This means that the thermal insulation element comprises a multitude of layers or plies. The thermal insulation element can therefore also be referred to as a multi-layer thermal insulation element or a multi-layer insulation element. In particular, the thermal insulation element is a so-called multilayer insulation (MLI).

[0041] Furthermore, a method for detecting a leak in such a storage container for storing a cryogen is proposed. The storage container has an inner container for receiving the cryogen and a removal device for removing the cryogen from the inner container, wherein the removal device has a removal line that is in fluid communication with the inner container, an inner barrier in which the removal line is at least partially received and which encloses an inner volume, and an outer barrier in which the inner barrier is at least partially received and which encloses an outer volume. According to the invention, the inner volume is filled with a detection gas, wherein the detection gas has an overpressure compared to the outer volume.The method comprises the following steps: a) detecting a pressure change within the inner volume and / or a pressure change within the outer volume, and b) detecting, based on the respective pressure change, whether the sampling line, the inner barrier and / or the outer barrier has a leak.

[0042] The method is carried out, in particular, with the aid of the leak detection device described above. This method thus makes it possible to reliably detect or record whether the sampling line, the inner barrier, and / or the outer barrier is damaged or leaking.

[0043] According to one embodiment, a leak in the extraction line is detected when there is a pressure equalization between the extraction line and the inner volume and at the same time there is no pressure change in the outer volume, wherein a leak in the inner barrier is detected when there is a pressure drop in the inner volume and at the same time there is a pressure increase in the outer volume, and / or wherein a leak in the outer barrier is detected when there is a pressure increase in the inner volume and at the same time there is a pressure increase in the outer volume.

[0044] As previously explained, with the help of the respective pressure conditions it is possible to detect or determine whether the sampling line, the inner barrier and / or the outer barrier has a leak.

[0045] The embodiments and features described for the proposed storage container apply accordingly to the proposed method and vice versa.

[0046] "One" in this case is not necessarily to be understood as limiting the number to exactly one element. Rather, multiple elements, such as two, three, or more, can also be considered. Any other counting term used here should also not be understood as requiring a precise limitation to the corresponding number of elements. Rather, numerical deviations upwards and downwards are possible.

[0047] Further possible implementations of the storage container and / or the method also include combinations of features or embodiments described above or below with respect to the exemplary embodiments that are not explicitly mentioned. In this case, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the storage container and / or the method.

[0048] Further advantageous embodiments of the storage container and / or the method are the subject of the dependent claims and the exemplary embodiments of the storage container and / or the method described below. The storage container and / or the method are explained in more detail below using preferred embodiments with reference to the accompanying figures. Fig. 1 shows a schematic sectional view of an embodiment of a storage container for storing a cryogen;

[0049] Fig. 2 shows a schematic sectional view of an embodiment of a removal device for the storage container; and

[0050] Fig. 3 shows a schematic block diagram of an embodiment of a method for detecting a leak in the storage container according to Fig. 1.

[0051] In the figures, identical or functionally equivalent elements have been given the same reference numerals unless otherwise stated.

[0052] Fig. 1 shows a schematic sectional view of an embodiment of a storage container 1 for storing a cryogen.

[0053] The storage vessel 1 can also be referred to as a storage tank. The storage vessel 1 is preferably suitable for holding hydrogen H2 (boiling point: 1 bara: 20.268 K = -252.882 °C) as a cryogen. Therefore, the storage vessel 1 can also be referred to as a hydrogen storage vessel or 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, in addition to the aforementioned hydrogen H2, are liquid helium He (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). The cryogen preferably has a pressure of 2 to 20 bara, particularly preferably 2 to 17 bara.

[0054] The storage container 1 can be a transport container. For example, liquid hydrogen LH2 can be transported using the storage container 1. The storage container 1 can be part of a vehicle, in particular a watercraft. In this case, the storage container 1 is suitable for mobile applications. However, the storage container 1 can also be used stationary, for example in building technology. The storage container 1 is constructed rotationally symmetrically to a symmetry or central axis 2. The central axis 2 is oriented perpendicular to a direction of gravity g. The storage container 1 comprises a first container or inner container 3, which is also constructed rotationally symmetrically to the central axis 2. The inner container 3 comprises a tubular or cylindrical base section 4, which is also constructed rotationally symmetrically to the central axis 2. The base section 4 can have a circular or approximately circular geometry in cross-section.

[0055] The base section 4 is closed at both ends by a lid section 5, 6. The lid sections 5, 6 are curved. A first lid section 5 and a second lid section 6 are curved in opposite directions, so that the lid sections 5, 6 are curved outward relative 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.

[0056] The cryogen, in this example liquid hydrogen LH2, is accommodated in the inner container 3. As long as the hydrogen H2 is in the two-phase region, a gas zone 7 with gaseous hydrogen GH2 and a liquid zone 8 with liquid hydrogen LH2 can be provided in the inner container 3. After being filled into the inner container 3, the hydrogen H2 therefore has two phases with different states of aggregation, namely liquid and gaseous. This means that in the inner container 3 there is a phase boundary 9 between the liquid hydrogen LH2 and the gaseous hydrogen GH2. The gaseous hydrogen GH2 can also be referred to as the gaseous phase. The liquid hydrogen LH2 can also be referred to as the liquid phase.

[0057] The inner container 3 is arranged entirely within a second container or outer container 10. The storage container 1 is thus double-walled. The outer container 10 is also constructed rotationally symmetrically to the central axis 2. The outer container 10, like the inner container 3, comprises a tubular or cylindrical base section 11, which is constructed rotationally symmetrically to the central axis 2. The base section 11 can have a circular or approximately circular geometry in cross-section. The base section 11 is closed at each end by a lid section 12, 13. In particular, a first lid section 12 and a second lid section 13 are provided. The lid sections 12, 13 are curved in opposite directions, so that the lid sections 12, 13 are curved outward relative to the base section 11. The outer container 10 is fluid-tight, in particular gas-tight. The outer container 10 is also made of stainless steel.

[0058] A gap 14 is provided between the inner container 3 and the outer container 10, completely enclosing or surrounding the inner container 3. The gap 14 is subjected to a vacuum. A "vacuum" in this case is understood to mean, in particular, a pressure of less than 300 mbar, preferably less than 10' 3 mbar, more preferably less than 10' 7 mbar. The storage container 1 is thus vacuum-insulated or vacuum-insulated. The fact that the gap 14 completely "encloses" or "envelops" the inner container 3 means, in this case, that the gap 14, on the one hand, completely surrounds the base section 4 and, on the other hand, is also provided between the two lid sections 5, 12 and between the two lid sections 6, 13. The outer container 10 delimits the storage container 1 from an environment 15 of the storage container 1.

[0059] A thermal insulation element or insulation element (not shown) is provided in the gap 14, completely enclosing or surrounding the inner container 3. This means that the thermal insulation element encloses both the base section 4 and the lid sections 5, 6 of the inner container 3. The thermal insulation element serves for thermal insulation. The thermal insulation element is multi-layered. This means that the thermal insulation element comprises a plurality of layers or plies. The thermal insulation element can therefore also be referred to as a multi-layer thermal insulation element or a multi-layer insulation element. In particular, the thermal insulation element is a so-called multilayer insulation (MLI).

[0060] Fig. 2 shows a schematic sectional view of an embodiment of a removal device 16 for the storage container 1.

[0061] The extraction device 16 has an extraction line 17, which in the present example opens out of the liquid zone 8 of the storage tank 1. Alternatively, the extraction line can also open out of the gas zone of the storage tank (not shown in the figures). Liquid hydrogen LH2 can be extracted from the storage tank 1 using the extraction line 17. The liquid hydrogen LH2 can then, for example, be vaporized and supplied as gaseous hydrogen GH2 to a consumer, for example in the form of a fuel cell. The extraction device 16 is attached to the underside of the storage tank 1.

[0062] The liquid hydrogen LH2 can flow into the extraction line 17 due to its hydrostatic pressure. The extraction line 17 runs through the inner container 3 and through the outer container 10. For example, the extraction line 17 can be welded or soldered into the inner container 3, in particular into the base section 4 of the inner container 3. The extraction line 17 passes through the gap 14. The extraction line 17 does not contact the outer container 10. As shown in Fig. 2, the extraction line 17 can be curved. However, the extraction line 17 can also be straight.

[0063] A valve 18 is connected to the extraction line 17. The valve 18 can be an on-off valve. This means that the valve 18 can be either fully open or closed. However, the valve 18 can also be designed to continuously adjust a volume flow of the liquid hydrogen LH2 flowing through the valve 18. A rod-shaped actuating element 19 is assigned to the valve 18 and is coupled to a valve body of the valve 18. For example, the valve 18 can be opened and closed with the aid of the actuating element 19, for example by rotating the valve body. The actuating element 19 can be actuated manually. Alternatively, a drive element 20, for example in the form of an electric motor, can be coupled to the actuating element 19 in order to actuate the valve 18.

[0064] The extraction line 17 is at least partially enclosed by a first or inner barrier 21. The inner barrier 21 is tubular and follows the course of the extraction line 17. The inner barrier 21 is connected in a gas-tight manner to the inner container 3, in particular to the base section 4 of the inner container 3.

[0065] For example, the inner barrier 21 can be welded or soldered to the base section 4. The inner barrier 21 extends through the gap 14 and through the outer container 10, in particular through the base section 11 of the outer container 10. The inner barrier 21 does not contact the outer container 10.

[0066] The inner barrier 21 has a receiving section 22 in which the valve 18 is received. The receiving section 22 can be cylindrical or box-shaped. The receiving section 22 encloses or encapsulates the valve 18 in a gas-tight manner. The actuating element 19 extends from the receiving section 22 in a gas-tight manner. For this purpose, a suitable seal can be provided between the actuating element 19 and the receiving section 22, which enables movement, in particular rotation, of the actuating element 19 relative to the receiving section 22. The extraction line 17 extends from the receiving section 22 in a gas-tight manner. For this purpose, the extraction line 17 can be welded or soldered into the receiving section 22, for example.

[0067] The inner barrier 21 encloses or encapsulates a fixed and closed first or inner volume 23, through which the withdrawal line 17 is led at least in section and in which the valve 18 is arranged. The inner volume 23 is filled with a detection gas He. The detection gas He in the present case is helium and is therefore also referred to below as helium. The helium He in the inner volume 23 has an overpressure compared to the outer volume 32, i.e. during the withdrawal of cryogen via the withdrawal line 17 or during withdrawal-free times. The inner volume 23 is filled with the helium He under controlled conditions, usually at a predetermined pressure and a predetermined temperature.The pressure of the helium He in the inner volume 23 is selected such that, when hydrogen LH2 is withdrawn via the withdrawal line 17, the helium He always maintains an overpressure relative to the outer volume 32, despite cooling and the associated pressure reduction. Preferably, when cryogen LH2 is withdrawn via the withdrawal line 17, the detection gas He in the inner volume 23 has an overpressure relative to the outer volume 32 of 0.3 to 4 bara, particularly preferably 0.3 to 1 bara. This can be achieved, for example, by introducing the helium He into the inner volume 23 at a temperature between 0 and 30°C and a pressure of 8 bara. Associated with the inner volume 23 is an internal pressure sensor or internal pressure transducer 24, with the aid of which the pressure of the helium He in the inner volume 23 can be detected. The inner pressure sensor 24 can be coupled to the inner barrier 21 via an inner pressure sensor line 25.The inner pressure sensor line 25 can be welded or soldered into the inner barrier 21.

[0068] The sampling device 16 is assigned an evaluation unit 26, which is operatively connected to the internal pressure sensor 24 via a data connection 27. The data connection 27 can be wired or wireless. The evaluation unit 26 can be a computer or comprise a computer. The evaluation unit 26 can, for example, have a screen with the aid of which the pressure of the helium He within the internal volume 23 can be displayed. The internal pressure sensor 24 and the evaluation unit 26 are part of a leak detection device 28 for determining, detecting, or recording a leak in the sampling device 16. The leak detection device 28 can also have the internal pressure sensor line 25 and the data connection 27. The leak detection device 28 can be part of the sampling device 16.

[0069] The leak detection device 28 can have a temperature measuring function for measuring an external temperature of the extraction line 17. The temperature measuring function of the leak detection device 28 is explained below. The internal volume 23 is defined and unchangeable. Since the helium He was introduced into the internal volume 23 under controlled conditions, a specific pressure of the helium He in the internal volume 23 can be unequivocally assigned to a specific temperature of the helium He. If the temperature of the helium He in the internal volume 23 changes, for example, if the extraction line 17 heats up due to an interruption in the volume flow of liquid hydrogen LH2 flowing through the extraction line 17, the internal volume 23 itself cannot change, but the pressure of the helium He in the internal volume 23 changes. An isochoric change of state of the helium He occurs. "Isochoric" is a term in thermodynamics.It describes a change in the state of a substance, in this case helium (He), in which its volume, in this case the internal volume 23, remains constant. The following then applies:

[0070] Where p is the pressure and T is the temperature of the helium He within the inner volume 23. It follows that a relative change in pressure p corresponds to a relative change in temperature T: p2 _ T2 pl ~ TI

[0071] Here, p1 stands for the absolute pressure before heat is added, p2 for the absolute pressure after heat is added, T1 for a temperature before heat is added, and T2 for a temperature after heat is added. If the pressure p2 is measured using the internal pressure sensor 24, the temperature T2 can be determined, for example, using a suitable table. Such a table can be stored electronically in the evaluation unit 26 so that the evaluation unit can output the temperature T2. The temperature T2 of the helium He then corresponds to an external temperature of the extraction line 17. The temperature T2 of the extraction line 17 after it has been heated can thus be measured indirectly using the leakage detection device 28. The same applies to cooling of the extraction line 17. This eliminates the need to provide temperature sensors directly on the extraction line 17.

[0072] The inner barrier 21 or the inner volume 23 is assigned a first or internal overpressure protection device 29, for example in the form of a rupture disc, which is suitable for opening the inner volume 23 to the environment 15 when a defined overpressure is reached. The internal overpressure protection device 29 can be attached to the inner pressure sensor line 25. The internal overpressure protection device 29 can have a sensor system that sends a sensor signal to the evaluation unit 26 when the internal overpressure protection device 29 is triggered. In other words, the evaluation unit 26 can detect the triggering of the internal overpressure protection device 29 and, if necessary, emit an acoustic and / or optical signal.

[0073] Returning now to the extraction device 16, it has a second or outer barrier 30 which at least partially encapsulates or surrounds the inner barrier 21, wherein the inner barrier 21 at least partially encapsulates or surrounds the extraction line 17. The inner pressure sensor line 25 is passed through the outer barrier 30. For example, the inner pressure sensor line 25 can be welded or soldered into the outer barrier 30. The outer barrier 30 is tubular and follows a course of the extraction line 17. The outer barrier 30 is connected in a gas-tight manner to the outer container 10, in particular to the base section 11 of the outer container 10. For example, the outer barrier 30 can be welded or soldered into the base section 11. The outer barrier 30 does not contact the inner container 3.

[0074] The outer barrier 30 leads from the outer container 10 to a valve box 31. The valve box 31 can also be referred to as a valve box. The outer barrier 30 is connected to the valve box 31 in a gas-tight manner. For example, the outer barrier 30 can be welded or soldered to the valve box 31. The outer barrier 30 encloses a second or outer volume 32, which is subjected to a vacuum. The outer volume 32 is in fluid communication with the gap 14. In other words, the outer volume 32 and the gap 14 form a common gas space. The outer volume 32, like the gap 14, is subjected to a vacuum. As previously mentioned, a thermal insulation element 33, in particular in the form of an MLI, is accommodated in the gap 14. The thermal insulation element 33 can be wound onto the inner container 3. The thermal insulation element 33 can also fill the outer volume 32 at least in sections.In this case, the thermal insulation element 33 is wound onto the inner barrier 21.

[0075] The valve box 31 encloses a receiving space 34, within which the valve 18 and other valves (not shown) are arranged. The inner barrier 21 extends into the receiving space 34. The outer volume 32 is not in fluid communication with the receiving space 34. The actuating element 19 extends gas-tight from the valve box 31, so that the drive element 20 is arranged outside the valve box 31. The inner barrier 21 ends with the receiving section 22, in which the valve 18 is accommodated, in the receiving space 34. The extraction line 17 extends out of the valve box 31. The valve box 31 can be vacuum-insulated. An external pressure sensor or external pressure transducer 35 is assigned to the outer volume 32. The external pressure transducer 35 can be connected to the outer barrier 30 by means of an external pressure transducer line 36. The outer pressure transducer line 36 can be welded or soldered into the outer barrier 30.Since the outer volume 32 is fluidly connected to the gap 14, the outer pressure sensor 35 can also be positioned anywhere on the outer container 10. The outer pressure sensor 35 is operatively connected to the evaluation unit 26 via a data connection 37. The data connection 37 can be wired or wireless. The outer pressure sensor 35 is part of the leak detection device 28. The outer pressure sensor line 36 and the data connection 37 can also be part of the leak detection device 28.

[0076] The outer barrier 30 or the outer volume 32 is assigned a second or external overpressure protection device 38, for example in the form of a rupture disc, which is suitable for opening the outer volume 32 to the environment 15 when a defined overpressure is reached. The outer overpressure protection device 38 can be attached to the outer pressure sensor line 36. The outer overpressure protection device 38 can have a sensor system that sends a sensor signal to the evaluation unit 26 when the outer overpressure protection device 38 is triggered. In other words, the evaluation unit 26 can detect the triggering of the outer overpressure protection device 38 and, if necessary, emit an acoustic and / or optical signal.

[0077] The function of the extraction device 16 is explained below. The most critical area for leaks is the extraction line 17 upstream of the valve 18. If a leak occurs in this area on the extraction line 17, it can lead to the entire storage vessel 1 emptying. This can cause the liquid hydrogen LH2 to come into contact with the thermal insulation element 33 and damage it. The outer vessel 10 cools down to such an extent that air components condense on it. These condensed air components drip into a drip tray arranged below the storage vessel 1 and evaporate. This continues until all of the liquid hydrogen LH2, which can have a mass of several tons, evaporates and is vented via the emergency relief valves of the storage vessel 1. If the storage vessel 1 has a foundation that cannot withstand cryogenic temperatures, it will cool down well beyond its design temperature and be destroyed.This is true, for example, when carbon steels, often used in shipbuilding, are used as foundation materials. A leak in the outer barrier 30 leads to a loss of vacuum in the outer volume 32 and the gap 14, and consequently to the undesirable result discussed above.

[0078] With the aid of the extraction device 16, a vacuum loss in the event of a leak can now be detected or sensed, and the foundation can be protected from excessively low temperatures. For this purpose, the extraction device 16 comprises the two barriers 21, 30 and the leak detection device 28. Together with the extraction line 17, the two barriers 21, 30 result in a three-layer structure of the extraction device 16.

[0079] If the extraction line 17 breaks, the liquid hydrogen LH2 flows into the inner volume 23 and is collected there. The liquid hydrogen LH2 cannot reach the thermal insulation element 33 and the vacuum in the outer volume 32 and the gap 14 does not collapse. Temperature-related damage to the foundation is prevented. Pressure equalization occurs between the inner volume 23 and the extraction line 17. If the pressure of the helium He in the inner volume 23 and in the extraction line 17 equalizes, it can be deduced that a leak exists between the extraction line 17 and the inner volume 23. This pressure equalization is detected by the internal pressure sensor 24. The evaluation unit 26 can then output, for example, visually and / or acoustically, that a leak has occurred in the extraction line 17.

[0080] If a leak now occurs between the inner volume 23 and the outer volume 32, for example in the form of a crack in the inner barrier 21, the pressure of the helium He in the inner volume 23 decreases because the helium He flows from the inner volume 23 into the outer volume 32. This pressure drop is detected with the help of the inner pressure sensor 24. In addition, the pressure in the outer volume 32 will rise and may trigger the external overpressure protection device 38. From the fact that the pressure of the helium He in the inner volume 23 decreases and the pressure in the outer volume 32 increases and may trigger the external overpressure protection device 38, it can be concluded that there is a leak in the inner barrier 21. With the help of the evaluation unit 26, it can then be output, for example visually and / or acoustically, that a leak has occurred at the inner barrier 21.

[0081] If the outer barrier 30 develops a leak, the vacuum in the outer volume 32 will collapse, which can be detected using the external pressure sensor 35. Because the vacuum in the outer volume 32 is lost, the thermal insulation effect of the outer volume 32 can no longer be guaranteed. Heat introduced into the inner barrier 21 then ensures that the pressure of the helium He in the inner volume 23 immediately rises and, if necessary, the internal overpressure protection device 29 is triggered. From this, it can then be concluded that there is a leak in the outer barrier 30. Here, too, an optical and / or acoustic signal can then be output using the evaluation unit 26, for example.

[0082] Fig. 3 shows a schematic block diagram of an embodiment of a method for detecting a leak in the storage container 1.

[0083] In the method, in a step S1, a pressure change within the inner volume 23 enclosed by the inner barrier 21 and / or a pressure change within the outer volume 32 enclosed by the outer barrier 30 is detected. In a step S2, the respective pressure change is used to determine whether the extraction line 17, the inner barrier 21, and / or the outer barrier 30 is leaking.

[0084] In particular, a leak in the extraction line 17 is detected when there is pressure equalization between the extraction line 17 and the inner volume 23 and, at the same time, there is no pressure change in the outer volume 32. Furthermore, a leak in the inner barrier 21 is detected when there is a pressure drop in the inner volume 23 and, at the same time, a pressure increase in the outer volume 32. A leak in the outer barrier 30 is detected when there is a pressure increase in the inner volume 23 and, at the same time, a pressure increase in the outer volume 32.

[0085] Although the present invention has been described using exemplary embodiments, it can be modified in many ways.

[0086] Reference symbols used

[0087] 1 storage tank

[0088] 2 central axis

[0089] 3 inner containers

[0090] 4 Basic section

[0091] 5 Lid section

[0092] 6 Lid section

[0093] 7 Gas Zone

[0094] 8 Liquid zone

[0095] 9 Phase boundary

[0096] 10 outer containers

[0097] 11 Base section

[0098] 12 Lid section

[0099] 13 Lid section

[0100] 14 gap

[0101] 15 Surroundings

[0102] 16 Removal device

[0103] 17 Withdrawal line

[0104] 18 Valve

[0105] 19 Actuating element

[0106] 20 drive element

[0107] 21 Barrier

[0108] 22 Recording section

[0109] 23 volumes

[0110] 24 pressure sensors

[0111] 25 Pressure sensor line

[0112] 26 Evaluation unit

[0113] 27 Data connection

[0114] 28 Leakage detection device

[0115] 29 Overpressure protection

[0116] 30 Barrier

[0117] 31 Valve box

[0118] 32 volumes

[0119] 33 Thermal insulation element 34 Accommodating space

[0120] 35 pressure sensors

[0121] 36 Pressure sensor line

[0122] 37 Data connection 38 Overpressure protection g Gravity direction

[0123] GH2 gaseous phase / gaseous hydrogen

[0124] H2 Cryogen / Hydrogen He Detection gas / Helium

[0125] LH2 liquid phase / liquid hydrogen

[0126] 51 steps

[0127] 52 steps

Claims

Patent claims 1. A storage container (1) for storing a cryogen (H2), comprising an inner container (3) for receiving the cryogen (H2), and a removal device (16) for removing the cryogen (H2) from the inner container (3), wherein the removal device (16) comprises: a removal line (17) which is in fluid communication with the inner container (3), an inner barrier (21) in which the removal line (17) is accommodated at least in sections and which encloses an inner volume (23), wherein the inner volume (23) is filled with a detection gas (He), an outer barrier (30) in which the inner barrier (21) is accommodated at least in sections and which encloses an outer volume (32), wherein the detection gas (He) in the inner volume (23) has an overpressure compared to the outer volume (32), and a leak detection device (28) which is configured toto detect, based on a pressure change within the inner volume (23) and / or based on a pressure change within the outer volume (32), whether the extraction line (17), the inner barrier (21) and / or the outer barrier (30) has a leak.

2. Storage container according to claim 1, wherein the storage container (1) has an outer container (10) which encloses the inner container (3), wherein a gap (14) is provided between the inner container (3) and the outer container (10), wherein the gap (14) is subjected to a vacuum, and wherein the outer volume (32) is in fluid communication with the gap (14).

3. Storage container according to claim 2, wherein the outer barrier (30) is connected to the outer container (10) in a gas-tight manner.

4. Storage container according to one of claims 1 - 3, wherein the inner barrier (21) is connected to the inner container (3) in a gas-tight manner.

5. Storage container according to one of claims 1 - 4, wherein the leak detection device (28) has an internal pressure sensor (24) for detecting a pressure change in the internal volume (23) and an external pressure sensor (35) for detecting a pressure change in the external volume (32).

6. Storage container according to claim 5, wherein the leak detection device (28) has an internal overpressure protection device (29) for protecting the inner barrier (21) against overpressure and an external overpressure protection device (38) for protecting the outer barrier (30) against overpressure.

7. Storage container according to claim 5 or 6, wherein the leakage detection device (28) has an evaluation unit (26) operatively connected to the inner pressure sensor (24) and to the outer pressure sensor (35), which detects a leak in the extraction line (17) when there is a pressure equalization between the extraction line (17) and the inner volume (23) and at the same time there is no pressure change in the outer volume (32), which detects a leak in the inner barrier (21) when there is a pressure drop in the inner volume (23) and at the same time there is a pressure increase in the outer volume (32), and / or which detects a leak in the outer barrier (30) when there is a pressure increase in the inner volume (23) and at the same time there is a pressure increase in the outer volume (32).

8. Storage container according to one of claims 1 - 7, wherein the detection gas (He) in the inner volume (23) has an overpressure of 0.3 to 4 bara, in particular of 0.3 to 1 bara, compared to the pressure prevailing in the outer volume (32).

9. Storage container according to one of claims 1 - 8, wherein the removal device (16) has a valve box (31) which encloses a receiving space (34) within which a valve (18) connected into the removal line (17) is accommodated.

10. Storage container according to claim 9, wherein the outer barrier (30) is connected gas-tight to the valve box (31), and wherein the outer volume (32) is fluidically separated from the receiving space (34).

11. Storage container according to claim 9 or 10, wherein the inner barrier (21) ends within the receiving space (34), and wherein the inner volume (23) is fluidically separated from the receiving space (34).

12. Storage container according to one of claims 9 - 11, wherein the inner barrier (21) encloses the valve (18) in a gas-tight manner.

13. Storage container according to one of claims 1 - 12, wherein the inner container (3) and / or the inner barrier (21) are enclosed by a thermal insulation element (33).

14. A method for detecting a leak in a storage container (1) for storing a cryogen (H2), wherein the storage container (1) has an inner container (3) for receiving the cryogen (H2), and a removal device (16) for removing a liquid phase (LH2) of the cryogen (H2) from the inner container (3), wherein the removal device (16) has a removal line (17) which is in fluid communication with the inner container (3), an inner barrier (21) in which the removal line (17) is at least partially received and which encloses an inner volume (23), wherein the inner volume (23) is filled with a detection gas (He), and an outer barrier (30) in which the inner barrier (21) is at least partially received and which encloses an outer volume (32), wherein the detection gas (He) has an overpressure compared to the outer volume (32). has, has,with the following steps: a) detecting (S1) a pressure change within the inner volume (23) and / or a pressure change within the outer volume (32), and b) detecting (S2) on the basis of the respective pressure change whether the extraction line (17), the inner barrier (21) and / or the outer barrier (30) has a leak.

15. The method according to claim 14, wherein a leak in the extraction line (17) is detected when there is a pressure equalization between the extraction line (17) and the inner volume (23) and at the same time there is no pressure change in the outer volume (32), wherein a leak in the inner barrier (21) is detected when there is a pressure drop in the inner volume (23) and at the same time there is a pressure increase in the outer volume (32), and / or wherein a leak in the outer barrier (30) is detected when there is a pressure increase in the inner volume (23) and at the same time there is a pressure increase in the outer volume (32).

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