CRYOGEN STORAGE SYSTEM

Description

Field of the invention

[0001] The present invention relates to a storage system for storing a cryogenic medium, in particular for storing hydrogen. The invention also relates to a device comprising such a storage system and a consumer for the medium contained in the storage container of the storage system. State of the art

[0002] It is known that cryogenic media, i.e., extremely cold and at least partially liquid media, such as hydrogen or helium, can be stored in a storage container to transport energy, for example, to power a vehicle, ship, aircraft, or rocket. The medium is usually present partly in liquid form in the storage container and partly in gaseous form.

[0003] In conventional cryogenic storage systems, various pipes are arranged to connect the internal tank and the external environment of the storage system. These pipes are required for various purposes, such as conveying cryogenic liquid medium from the internal tank to the heat exchanger or evaporator, and finally to a consumer. Sometimes such storage systems also have a pressurization system, which, depending on the type, can be an open or closed system. A pressurization system can compensate for the pressure drop that occurs during the gaseous or liquid withdrawal of, for example, hydrogen. This is usually achieved either by an internal tank heat exchanger (closed piping system) or by direct evaporation (open system).

[0004] In conventional cryogenic storage systems, there is a withdrawal line, which connects the interior of the tank to a consumer. A failure of a component in this withdrawal line typically results in a system failure (shutdown), as the supply of medium from the interior tank to the consumer is no longer possible.

[0005] From US 2007 193 275 A1, a motor unit, in particular for urban transport, is known, comprising an engine supplied with a compressed gas and having an expansion chamber provided with a piston arranged to cyclically perform a working stroke and an exhaust stroke during each double stroke; a liquefied gas tank connected to the engine;and means for gasifying the liquefied gas arranged between the liquefied gas tank and the engine to obtain compressed gas, the gasification means comprising a gasification chamber in communication with the liquefied gas tank and a liquid fuel tank connected to the gasification chamber, the gasification chamber being in fluid communication with both the liquid fuel tank for combustion of the liquid fuel with the oxygen of the liquefied gas and the expansion chamber so that a gas mixture comprising compressed liquefied gas and gaseous products of the combustion process is used to perform useful work.; Summary of the invention

[0006] It is an object of the invention to provide a storage system for storing a cryogenic medium and a device comprising such a storage system and a consumer for the medium accommodated in the storage container of the storage system, which is fault-tolerant, wherein in particular in the event of a failure of an individual component of a withdrawal line, there should be no total failure of the supply to a consumer from the storage system.

[0007] The object is achieved by a storage system for storing a cryogenic medium, in particular for storing hydrogen, according to claim 1.

[0008] The storage system comprises a storage tank for receiving the medium, wherein a first withdrawal line forms a fluid-conducting connection from the interior of the storage tank to a consumer connection for connecting a consumer, wherein at least one first controllable line shut-off valve and a first heat exchanger are arranged in the first withdrawal line, wherein a second withdrawal line different from the first withdrawal line forms a fluid-conducting connection from the interior of the storage tank to a consumer connection for connecting the same consumer, wherein at least one second controllable line shut-off valve and a further first heat exchanger are arranged in the second withdrawal line.

[0009] According to the invention, the first extraction line additionally has an internal tank heat exchanger downstream of the first heat exchanger, and the second extraction line additionally has another internal tank heat exchanger downstream of the other first heat exchanger. The internal tank heat exchanger in each extraction line serves to control or regulate the pressure inside the storage container using the heated extracted medium.

[0010] According to the invention, the withdrawal line of a storage system comprises a controllable line shut-off valve to control the withdrawal of the medium from the storage container into the withdrawal line and, downstream of this line shut-off valve, a first heat exchanger which serves to temper the withdrawn medium, in particular hydrogen, to the desired withdrawal conditions, in particular to heat it and possibly, if a liquid medium was withdrawn, also to evaporate it. According to the invention, such a withdrawal line is redundantly designed twice - or even more often - from the inner container to a consumer. Therefore, according to the invention, there is a first withdrawal line and a different second withdrawal line, wherein each of the withdrawal lines has similar components so that the withdrawal lines can perform the same function.In particular, both the first and the second extraction line have an associated line shut-off valve to control the inflow into the extraction line, as well as an associated heat exchanger to temper the medium to the desired extraction conditions.

[0011] In conventional cryogenic storage systems, the number and type of piping is kept to a minimum for thermodynamic reasons. In contrast, the invention uses a larger number of components.

[0012] Individual component failures therefore no longer lead to a total failure (shutdown) of the system, since the components and the connection to the consumer are not simply connected to the inner tank, but are designed redundantly.

[0013] For example, the first and second extraction lines can both be configured to extract gaseous medium from the storage container, or both can be configured to extract liquid medium from the storage container. For example, the first extraction line can also be configured to extract gaseous medium from the storage container, and the second extraction line can be configured to extract liquid medium from the storage container.

[0014] According to one embodiment, the consumer connection of the first extraction line and the consumer connection of the second extraction line are combined into a common connection. In an alternative embodiment, the two consumer connections are not combined into a common connection. The two consumer connections can thus form a common connection or two separate connections on the same consumer.

[0015] Preferably, the first extraction line additionally has a third controllable line shut-off valve directly upstream of the consumer connection, and the second extraction line additionally has a further third controllable line shut-off valve directly upstream of the consumer connection. The third controllable line shut-off valve can serve as a shut-off device upstream of the connected consumer.

[0016] Preferably, the first extraction line additionally has a second heat exchanger downstream of the inner tank heat exchanger, and the second extraction line additionally has a further second heat exchanger downstream of the further inner tank heat exchanger. The second heat exchangers ensure that the desired extraction conditions for the medium are maintained even after heat transfer through the inner tank heat exchanger of the respective extraction line.

[0017] Preferably, the first extraction line additionally has a partial flow control valve downstream of the first controllable line shut-off valve and upstream of the internal tank heat exchanger, and the second extraction line additionally has another partial flow control valve downstream of the second controllable line shut-off valve and upstream of the further internal tank heat exchanger. Via the partial flow control valves, only a portion of the extracted and heated medium can be optionally returned to the storage tank, to the respective internal tank heat exchanger.

[0018] In general, in a storage system according to the invention, all components of the first withdrawal line up to the consumer connection, such as pipes, heat exchangers and valves, can also be redundantly present in the second withdrawal line and arranged in the same order.

[0019] Preferably, the storage tank is double-walled, with an insulating vacuum space between the two walls of the storage tank. According to one embodiment, the first and second controllable line shut-off valves and / or the two first heat exchangers of the first and second extraction lines are arranged in the vacuum space, particularly preferably also the second heat exchangers of the first and second extraction lines.

[0020] According to another embodiment, the first and second controllable line shut-off valves and / or the first heat exchangers of the first and second extraction lines are arranged outside an outer container of the storage container, wherein at least parts of lines outside an outer container of the storage container are designed as vacuum-insulated lines.

[0021] The storage container can also comprise at least one secondary vacuum space or space with an inert gas atmosphere—in particular in addition to a vacuum space between the inner and outer walls of the container—wherein the first and second controllable line shut-off valves and / or the first heat exchangers of the first and second extraction lines—and preferably all components of the first and second extraction lines—are arranged in the secondary vacuum space or space with an inert gas atmosphere. Particularly preferably, the components for the first and second extraction lines are each arranged in a separate secondary vacuum region or space with an inert gas atmosphere, i.e., each assigned to the first and second extraction lines, respectively, so that each extraction line has its own secondary vacuum space or space with an inert gas atmosphere.

[0022] The object is also achieved by a device comprising a storage system, as described above, and a consumer for the medium held in the storage container, wherein the consumer connection of the first extraction line and the consumer connection of the second extraction line are connected to the consumer. The consumer connection of the first extraction line and the consumer connection of the second extraction line can be combined to form a common connection at the consumer or, instead, not be combined to form a common connection at the consumer, thus forming two separate connections at the consumer. Brief description of the drawings

[0023] The invention is described below by way of example with reference to the drawings. Fig. 1 is a schematic representation of a storage system according to the invention. Fig. 2 is a schematic representation of a storage system according to the invention in an alternative embodiment. Fig. 3 is a schematic representation of a storage system according to the invention in an alternative embodiment. Fig. 4 is a schematic representation of a storage system according to the invention in an alternative embodiment. Fig. 5 is a schematic representation of a storage system according to the invention in an alternative embodiment. Fig. 6 is a schematic representation of a storage system according to the invention in an alternative embodiment. Fig. 7 is a schematic representation of a storage system according to the invention in an alternative embodiment. Fig. 8 is a schematic representation of a storage system according to the invention in an alternative embodiment.Fig. 9 is a schematic representation of a storage system according to the invention in an alternative embodiment. Fig. 10 is a schematic representation of a storage system according to the invention in an alternative embodiment. Detailed description of the invention

[0024] In the Fig.1 a storage system according to the invention for storing a cryogenic medium, in particular for storing hydrogen, is shown.

[0025] The storage system comprises a storage container 1 for holding the medium. The storage container 1 forms an inner container of a double-walled container, which additionally comprises an outer container 11. A vacuum is created between the outer container 11 and the inner container, i.e., storage container 1. Suspensions 13 are also arranged in sections between the outer container 11 and the inner container to position the two shells of the double-walled container relative to each other.

[0026] The cryogenic medium, in particular hydrogen, is located in the lower area of ​​the storage container 1, namely below the liquid surface shown as a wavy line in the figures as a liquid in the container, above the wavy liquid surface in a gaseous state.

[0027] A gas extraction line 2 is configured to extract the gaseous medium from the storage tank 1, so that the free end of the gas extraction line 2 terminates above the liquid surface, near the ceiling of the storage tank 1, in the storage tank 1. The first extraction line begins with the gas extraction line 2.

[0028] A liquid extraction line 5 is configured to extract the liquid medium from the storage tank 1, so that the free end of the liquid extraction line 5 terminates below the liquid surface, near the bottom of the storage tank 1, in the storage tank 1. The second extraction line begins with the liquid extraction line 5.

[0029] The terms "ceiling" and "floor" refer to the usual installation position of the storage container, for example in a moving, floating or flying transport device, whereby gravity acts towards the floor of the storage container during normal operation of the transport device.

[0030] A first controllable line shut-off valve 6 is arranged in the gas extraction line 2 and a second controllable line shut-off valve 7 is arranged in the liquid extraction line 5. Both line shut-off valves are located outside the storage tank 1. In the Fig. 1the line shut-off valves are also located outside the outer tank 11.

[0031] In the alternative version of the storage system, the Fig. 2 As shown, the two line shut-off valves 6, 7 are arranged within the outer container 11, i.e. between the inner container, storage container 1, and the outer container 11 of the double-walled storage container, namely in the vacuum space.

[0032] The line shut-off valves are controlled by a control device, which is also located in the vacuum chamber ( Fig.2 ) or outside the entire container ( Fig. 1 ) can be arranged. The flow can be controlled not only by the line shut-off valves but also by the flow can be reduced.

[0033] The storage tank 1 can also be refueled from a refueling device 14 via the gas extraction line 2 and / or the liquid extraction line 5, preferably also via the first line shut-off valve 6 and / or the second line shut-off valve 7.

[0034] The gas extraction line 2 and the liquid extraction line 5 also run after the two line shut-off valves 6, 7 as two separate lines, each with its own associated components, and therefore form two separate extraction lines.

[0035] The gas extraction line 2 and the liquid extraction line 5 are designed as separate extraction lines with the respective associated outside of the storage tank 1, for example between storage tank 1 and outer tank 11 of the double-walled storage tank ( Fig. 2 ), arranged, first heat exchanger 3 for heating the extracted medium.

[0036] Downstream of the first heat exchanger 3, an inner tank heat exchanger 4 is arranged within the storage tank 1 for heating the liquid medium in the storage tank 1. The heated medium drawn from the storage tank 1 flows through the inner tank heat exchanger 4. Due to the heating at the inner tank heat exchanger 4, the liquid medium in the storage tank 1 is partially heated and evaporated.

[0037] In the gas extraction line 2 and in the liquid extraction line 5 of the design according to Fig. 1 to Fig. 3 no controllable three-way valve, i.e. no partial flow valve 15 is arranged, so that the entire medium extracted through the gas extraction line 2 and / or through the liquid extraction line 5 and heated by the first heat exchanger 3 reaches the inner tank heat exchanger 4. In the embodiments according to Fig. 4 to Fig. 4a partial flow valve 15 is arranged in each extraction line, so that optionally only a part of the medium extracted through the gas extraction line 2 and / or through the liquid extraction line 5 and heated by the first heat exchanger 3 reaches the respective inner tank heat exchanger 4.

[0038] Downstream of the respective inner tank heat exchanger 4 and outside the storage tank 1, outside ( Fig. 1 ) or within ( Fig. 2 ) of the outer container 11 of the double-walled container, a second heat exchanger 8 for heating the medium is arranged in the first extraction line and in the second extraction line.

[0039] The medium flowing through the first and / or second extraction line is supplied downstream of the respective inner tank heat exchanger 4 to a same consumer via a respective consumer connection 10, in particular a fuel cell as the consumer. A third line shut-off valve 9 is arranged between the second heat exchanger 8 and the consumer 10 in each extraction line.

[0040] The design of the Fig. 2 differs from the Fig. 1 that control-relevant components of both withdrawal lines of the storage system, such as the first heat exchangers 3, the second heat exchangers 8, the first line shut-off valve 6 and the second line shut-off valve 8, are arranged inside the outer container 11, not outside the outer container 11 as in Fig. 1 , and are thus arranged in the space between the double-walled container, which forms a vacuum space.

[0041] Two separate areas of the vacuum chamber can be used exclusively for the heat exchangers 3, 8 of the first extraction line and for the heat exchangers 3, 8 of the second extraction line. This makes it easier to detect faults in one extraction line and to assign them to the relevant extraction line. The two areas of the vacuum chamber can be separated by the suspensions 13. However, the separation can also be achieved by at least one additional secondary vacuum chamber 12. All components of both extraction lines can also be installed in an additional secondary vacuum chamber 12 in order to avoid destroying the primary vacuum between the storage tank 1 and the outer tank 11 in the event of a fault, thus allowing the entire contents of the storage tank 1 to be emptied via the safety device ( Figs. 7 - 10). Instead of the secondary vacuum 12, an inert gas atmosphere (e.g. helium, nitrogen, argon) can also be created in the chamber 12.

[0042] In the execution of the Fig. 3 the lines running outside the storage tank between the components of the respective extraction line are designed as vacuum-insulated lines 16.

[0043] Thus, the cryogenic valves 6 and 7, as well as the heat exchangers 3 and 8, and the shut-off devices 9 can be positioned outside the tank system ( Fig. 1 ). For example, in cryogenic storage systems, where this cannot be easily realized technically due to the very low temperatures and associated ice formation or other safety-relevant conditions, these components can be stored within the vacuum range ( Fig.2) and only place the components outside that are necessary for the isolation. As an alternative, for example, to make better use of the installation space because no components need to be placed between the inner tank 1 and the outer tank 11, the cryogen-carrying lines and components can be connected using vacuum-insulated lines 16 to minimize or eliminate the occurrence of cryogenic temperatures or other safety-relevant problems ( Fig.3 ). At least three vacuum-insulated pipes should be used, preferably up to the first heat exchangers, to avoid ice formation or air liquefaction.

[0044] As already mentioned, the entire extraction flow can be directed through the inner tank heat exchanger 4 (see Fig. 1 , Fig. 2 and Fig. 3). However, this may be undesirable in some applications, which may require an additional component, namely a partial flow control valve 15. This serves, for example, to direct a percentage-controlled mass flow through the internal tank heat exchanger 4, whereby a controlled and thus stabilized operating range can be set (see Fig. 4 , Fig. 5 and Fig. 6 ).

[0045] In order to ensure that the medium can be extracted for mobile applications even in the event of individual faults, redundancy is introduced into the storage system according to the invention. However, duplication of the cryogenic valves, i.e. the first and second controllable line shut-off valves 6 and 7, is not necessary. This measure makes it possible to implement a system that can compensate for failures of individual components and therefore also prevent the loss of functionality of the storage system. There are two extraction lines that can differ in the type of extraction (gas, liquid). Due to the redundant design with two extraction lines that are not connected to one another, in the event of a failure or leak in one extraction line, the other can take over the full functionality of the other.Particularly in the aviation, shipping, and automotive sectors, such a scenario, in which a single failure or error leads to the shutdown of the entire refueling system, is undesirable. Another advantage is that, despite the redundant design, not significantly more components are required.

[0046] One withdrawal string can be designed and configured for the withdrawal of liquid cryogenic medium. The second string can provide the option for the withdrawal of gaseous medium. This allows the storage system to include the option to switch between withdrawal types, even with new piping, as may be desirable for improved tank system performance.

[0047] In order to detect the error in the event of a single fault and to enable the change of the sampling method, various methods for monitoring the system can be implemented: One method involves installing the components (all components required for the sampling, following the cryogenic valves) in an extended vacuum area (secondary vacuum) 12, for example at the front or along the tank axis ( Figs. 7 - 10 ). This allows leaks to be quickly identified from the outside, and a change in the extraction method can be implemented before the system fails. Another advantageous option is to set up a separate secondary vacuum area 12 for each of the first and second extraction lines. It should also be noted here that an inert gas atmosphere (e.g., helium, nitrogen, argon) can also be created in space 12 instead of the secondary vacuum.

[0048] For example, if this installation space cannot be used, in a second method, the sampling lines can be monitored by means of vacuum-insulated pipes 16 in order to detect any failures and leaks.

[0049] The components for the secondary system must therefore be designed differently or installed for a worst-case scenario for each withdrawal line. If necessary, this also means that the storage system can have two pressure build-up systems installed, as each withdrawal line should have the ability to regulate the tank pressure independently, as this component could also fail. List of reference symbols

[0050] 1Storage tank 2Gas extraction line 3First heat exchanger 4First inner tank heat exchanger 5Liquid extraction line 6First controllable line shut-off valve 7Second controllable line shut-off valve 8Second heat exchanger 9Third controllable line shut-off valve 10Consumer connection 11Outer tank 12Secondary vacuum chamber / inert gas atmosphere chamber 13Suspension 14Fueling device 15Partial flow control valve 16Vacuum-insulated line

Claims

1. Storage system for storing a cryogenic medium, in particular for storing hydrogen, comprising a storage container (1) for receiving the medium, wherein a first removal line forms a fluid-conducting connection from the interior of the storage container (1) to a consumer connection (10), for connecting a consumer, wherein at least a first controllable line shut-off valve (6) and a first heat exchanger (3) are arranged in the first removal line, wherein a second removal line which is different from the first removal line forms a fluid-conducting connection from the interior of the storage container (1) to a consumer connection (10) for connecting the same consumer, wherein at least a second controllable line shut-off valve (7) and a further first heat exchanger (3) are arranged in the second removal line characterized in that the first removal line additionally has an internal tank heat exchanger (4) downstream of the first heat exchanger (3) and the second removal line additionally has a further internal tank heat exchanger (4) downstream of the further first heat exchanger (3).

2. Storage system according to Claim 1, characterized in that the consumer connection (10) of the first removal line and the consumer connection (10) of the second removal line are combined together to form a common connection or are not combined together to form a common connection.

3. Storage system according to one of the aforementioned claims, characterized in that the first removal line additionally has a third controllable line shut-off valve (9) directly upstream of the consumer connection (10), and the second removal line additionally has a further third controllable line shut-off valve (9) directly upstream of the consumer connection (10).

4. Storage system according to one of the aforementioned claims , characterized in that the first removal line additionally has a second heat exchanger (8) downstream of the internal tank heat exchanger (4) and the second removal line additionally has a further second heat exchanger (8) downstream of the further internal tank heat exchanger (4).

5. Storage system according to one of the aforementioned claims , characterized in that the first removal line additionally has a flow control valve (15) downstream of the first controllable line shut-off valve (6) and upstream of the internal tank heat exchanger (4), and the second removal line additionally has a further flow control valve (15) downstream of the second controllable line shut-off valve (7) and upstream of the further internal tank heat exchanger (4).

6. Storage system according to one of the aforementioned claims, characterized in that all of the components of the first removal line as far as the consumer connection (10), such as lines, heat exchangers and valves, are also present as redundant components in the second removal line and are arranged in the same sequence.

7. Storage system according to one of the aforementioned claims, characterized in that the storage container (1) is configured to be double-walled with an insulating vacuum space between the two walls of the storage container (1), wherein the first and the second controllable line shut-off valve (6, 7) and / or the first heat exchangers (3) of the first and second removal line, preferably also the second heat exchangers (8) of the first and second removal line, are arranged in the vacuum space.

8. Storage system according to one of the aforementioned claims, characterized in that the storage container (1) is configured to be double-walled with an insulating vacuum space between the two walls of the storage container (1), wherein the first and the second controllable line shut-off valve (6, 7) and / or the first heat exchangers (3) of the first and second removal line are arranged outside an external container (11) of the storage container (1), wherein at least parts of the lines are configured outside the external container (11) of the storage container (1) as vacuum-insulated lines (16).

9. Storage system according to one of the aforementioned claims, characterized in that the storage container (1) comprises at least one secondary vacuum space or space with an inert gas atmosphere (12), wherein the first and second controllable line shut-off valve (6, 7) and / or the first heat exchangers (3) of the first and second removal line are arranged in the secondary vacuum space or space with an inert gas atmosphere (12), wherein preferably the components for the first and second removal line are arranged in each case in a separate secondary vacuum region or space with an inert gas atmosphere (12) of the first or second removal line.

10. Device comprising a storage system according to one of the aforementioned claims, and a consumer for the medium received in the storage container, characterized in that the consumer connection (10) of the first removal line and the consumer connection (10) of the second removal line are connected to the consumer, wherein the consumer connection (10) of the first removal line and the consumer connection (10) of the second removal line are combined together to form a common connection to the consumer, or are not combined together to form a common connection to the consumer.