Method and conveying device

Abstract

The invention relates to a method for conveying a cryogen (H2) from a storage container (2) to a load (3), having the following steps: a) introducing (S1) the cryogen (H2) from the storage container (2) into a conditioning container (8, 9, 10), b) bringing (S2) the cryogen (H2) received in the conditioning container (8, 9, 10) to its supercritical state, and c) discharging (S3) the cryogen (H2) from the conditioning container (8, 9, 10) to the load (3). The cryogen (H2) received in the conditioning container (8, 9, 10) is kept in the supercritical state during step c) in that a part of the cryogen (H2) is removed from the conditioning container (8, 9, 10), heated, and returned to the conditioning container (8, 9, 10) using a pressure build-up system (28, 29, 30), wherein the cryogen is received in a volume (31, 33) of the pressure build-up system (28, 29, 30) and is enclosed between valves (V5.1, V6.1; V5.1, V7.1) in the volume (31, 33), heat is supplied to the cryogen enclosed in the volume, and when a desired target pressure of the enclosed cryogen is reached, the cryogen is returned to the conditioning container (8, 9, 10).

Description

[0001] Description

[0002] Process and conveying device

[0003] The invention relates to a method and a conveying device for conveying a cryogen to a consumer, in particular for conveying hydrogen to a fuel cell.

[0004] From WO 2022 / 106053A1 a method is known comprising the following steps: introducing a cryogen from a storage container into a conditioning tank, bringing the cryogen contained in the conditioning tank into its supercritical state, and discharging the cryogen from the conditioning tank to the consumer, wherein during the discharging of the cryogen from the conditioning tank to the consumer the cryogen contained in the conditioning tank is kept in the supercritical state.

[0005] W02022 / 106053A1 forms the generic term of the independent patent claims.

[0006] The object of the present invention is to provide an improved method and an improved device for conveying a cryogen.

[0007] Accordingly, a method for conveying cryogen from a storage vessel to a consumer is proposed. The method comprises the following steps: a) introducing the cryogen from the storage vessel into a conditioning vessel, b) bringing the cryogen contained in the conditioning vessel into its supercritical state, and c) discharging the cryogen from the conditioning vessel to the consumer, wherein the cryogen contained in the conditioning vessel is maintained in the supercritical state during step c).According to the invention, during step c), the cryogen contained in the conditioning vessel is kept in the supercritical state by removing a portion of the cryogen from the conditioning vessel, heating it, and returning it to the conditioning vessel, wherein the cryogen is removed from the conditioning vessel with the aid of a pressure build-up system and returned to it, wherein the cryogen is received in a volume of the pressure build-up system and enclosed between valves in the volume, heat is supplied to the enclosed cryogen, and as soon as a desired target pressure of the enclosed cryogen is reached, the cryogen is returned to the conditioning vessel.

[0008] The volume can be formed by one or more lines, or by a container connected to the conditioning container via lines.

[0009] Because the cryogen stored in the conditioning vessel is kept in the supercritical state and thus no phase boundary exists, movement of the conditioning vessel, for example during rough seas, has no negative impact on the temperature distribution within the conditioning vessel. Furthermore, the storage vessel can be operated at the lowest possible pressure. This extends the cryogen's holding time. By removing a portion of the cryogen from the conditioning vessel, heating it, and then returning it to the conditioning vessel, the removed portion of the cryogen can be heated using an external heat source, for example in the form of an evaporator, in particular a water bath evaporator. A separate heating element for the conditioning vessel, such as an electric heating element, is no longer necessary. This simplifies the design and reduces costs.

[0010] The process is carried out using a conveying device for conveying the cryogen from the storage vessel to the consumer. The conditioning vessel is part of the conveying device. The conditioning vessel can also be referred to as a conditioning tank. To carry out the process, preferably several conditioning vessels are provided, which can be operated alternately or intermittently. For example, a first conditioning vessel, a second conditioning vessel, and a third conditioning vessel are provided. However, the number of conditioning vessels is arbitrary. At least one conditioning vessel is provided. Steps a), b), and c) are preferably carried out alternately between the conditioning vessels.This means, for example, that step a) is carried out simultaneously on or in a first conditioning container, step b) on or in a second conditioning container, and step c) is carried out on or in a third conditioning container. Steps a), b), and c) are carried out successively on or in each conditioning container.

[0011] Step b), or bringing the cryogen into its supercritical state, can also be referred to as conditioning or the conditioning process. Accordingly, "conditioning" or "conditioning" of the cryogen is understood here to mean bringing it into its supercritical state. This can be achieved by increasing the pressure in the respective conditioning vessel. The pressure increase can be caused, in particular, by introducing heat into the cryogen. The cryogen is constantly or always kept in the supercritical state during step c).

[0012] The cryogen is preferably hydrogen. The terms "cryogen" and "hydrogen 1can therefore be freely exchanged for one another in this case. In principle, however, the cryogen can also be any other cryogen. Examples of cryogenic fluids or liquids, or cryogens for short, include the aforementioned hydrogen, liquid helium, liquid nitrogen, or liquid oxygen. A "cryogen" is therefore understood to mean, in particular, a liquid. The cryogen can also be evaporated and thus converted into a gaseous phase. After evaporation, the cryogen is a gas or can be referred to as gaseous or evaporated cryogen. The gaseous phase can condense and thereby convert into a liquid phase of the cryogen. In particular, the conditioning vessel is filled with the liquid phase in step a).

[0013] In this context, "cryogen" can be understood to mean both the liquid phase and the gaseous phase of the cryogen. The supercritical state of the cryogen can also be subsumed under the term "cryogen." The liquid phase can, in particular, be evaporated and thus converted into the gaseous phase. Conversely, the gaseous phase can condense and thus be converted into the liquid phase. If both the gaseous and liquid phases exist simultaneously, a phase boundary exists between the liquid and the gaseous phases. The cryogen is thus in the two-phase region. In particular, the storage vessel is filled with both the liquid and the gaseous phases. This means that a phase boundary is provided within the storage vessel. At least after step a), a phase boundary can also be provided in the conditioning vessel.However, after step b), the cryogen in the conditioning vessel no longer exhibits a phase boundary. During step c), the cryogen in the conditioning vessel also exhibits no phase boundary.

[0014] The cryogen can be converted from the liquid phase to the gaseous phase, in particular through so-called phase transitions. In this case, this means, in particular, that the liquid phase can transition from liquid to gaseous into the gaseous phase through a phase transition. The liquid phase evaporates. Conversely, the gaseous phase can transition from gaseous to liquid into the liquid phase through a phase transition. The gaseous phase condenses. The cryogen thus has at least two states of matter, namely liquid and gaseous. However, the cryogen can also transition into a solid phase, for example, in the form of ice.

[0015] Since the storage container is preferably suitable for holding hydrogen, the storage container can also be referred to as a hydrogen storage container or a hydrogen storage tank. The consumer is preferably a fuel cell. A "fuel cell" in this case is understood to be a galvanic cell that converts the chemical reaction energy of a continuously supplied fuel, in this case hydrogen, and an oxidizing agent, in this case oxygen, into electrical energy. The cryogen is supplied to the consumer itself, particularly in gaseous form, at a defined supply pressure. This means that the cryogen is vaporized before or upstream of the consumer. For example, the cryogen is supplied to the consumer at a supply pressure of 6 bar and a temperature of 10 to 25 °C.

[0016] To introduce the cryogen from the storage vessel into the conditioning vessel, a withdrawal line is preferably provided between the storage vessel and the conditioning vessel. If multiple conditioning vessels are provided, further lines preferably branch off from the aforementioned withdrawal line, each of these lines leading to one of the conditioning vessels. The storage vessel is preferably arranged above the conditioning vessel with respect to a direction of gravity, so that the cryogen flows or is conveyed from the storage vessel into the conditioning vessel solely due to the hydrostatic pressure of the liquid phase.

[0017] After the cryogen is introduced from the storage vessel into the conditioning vessel, a valve provided between the storage vessel and the conditioning vessel is preferably closed. Furthermore, a valve provided between the conditioning vessel and the consumer is also closed. This means that the conditioning vessel is separated from the storage vessel and the consumer, forming a closed system. The cryogen contained in the conditioning vessel can then be conditioned during step b).

[0018] In thermodynamics, the critical point is a thermodynamic state of a substance, in this case cryogen, which is characterized by an equalization of the densities of the liquid phase and the gaseous phase. At the critical point, a phase boundary no longer exists. The differences between the two aforementioned states of matter cease to exist at the critical point. The cryogen is then in its supercritical state. At the critical point, the cryogen has a characteristic pressure, in particular a critical pressure, and a critical temperature. For example, hydrogen has a critical pressure of 12.3 bara and a critical temperature of -239.9 °C. This means in particular that in step b) the cryogen is preferably brought to an operating pressure that is higher than the critical pressure. For example, the operating pressure can be 14 bara.

[0019] The cryogen can be brought into the supercritical state, for example, by pressurizing it. For example, heat can be introduced into the conditioning vessel so that the pressure in the conditioning vessel increases. During step c), the cryogen is preferably kept in the supercritical state continuously, so that even when the cryogen is discharged from the conditioning vessel, the supercritical state is maintained while the consumer is supplied with the cryogen.

[0020] During step c), a portion of the cryogen contained in the conditioning vessel is removed from the conditioning vessel. This removed cryogen may be in the supercritical state. Heat is applied to the removed cryogen. This increases the pressure in the volume containing the removed portion of the cryogen. Once a desired target pressure of the removed cryogen is reached, it is returned to the conditioning vessel, allowing the cryogen contained in the conditioning vessel to be kept in the supercritical state throughout step c).

[0021] According to one embodiment, during step a), the cryogen flows from the storage vessel into the conditioning vessel only due to its hydrostatic pressure.

[0022] In this context, "hydrostatic pressure," "static pressure," "gravitational pressure," or "gravitational pressure" refers in particular to the pressure that develops within a static fluid, in this case the cryogen, due to the influence of gravity. The fact that the cryogen flows or is conveyed from the storage vessel into the conditioning vessel "only," "solely," or "merely" due to its hydrostatic pressure means, in particular, that the cryogen is conveyed from the storage vessel into the conditioning vessel without the supply of external energy, exclusively with the aid of hydrostatic pressure. The terms "only," "solely," "merely," or "exclusively" can therefore be interchanged at will. "Exclusively" means, in particular, that there is no other way of conveying the cryogen other than due to its hydrostatic pressure. "Flowing" can, in particular, be replaced by "being conveyed."This flow or conveyance of the cryogen from the storage vessel to the conditioning vessel solely due to its hydrostatic pressure can, as previously mentioned, be achieved, for example, by arranging the storage vessel, viewed along the direction of gravity, at least in part above or above the conditioning vessel. In particular, a point or region at which the cryogen is discharged from or removed from the storage vessel is arranged higher or above a point or region at which the cryogen is introduced into or supplied to the conditioning vessel. A pump for conveying the cryogen from the storage vessel into the conditioning vessel is thus unnecessary and can therefore be dispensed with. The method, in particular step a) of the method, is accordingly carried out "pumpless" or "pump-free."This means, in particular, that in step a), the cryogen is introduced or conveyed from the storage vessel into the conditioning vessel without a pump or pump-free. Step a) can therefore also be described as follows: introducing the cryogen from the storage vessel into the conditioning vessel without a pump. The same applies to step c). Accordingly, step c) can also be carried out without a pump or pump-free. Accordingly, step c) can also be described as follows: discharging the cryogen from the conditioning vessel to the consumer without a pump. Eliminating a pump or pumps leads to greater reliability of the process or conveying device, since moving parts can be dispensed with.

[0023] According to a further embodiment, during step b), the cryogen is brought into the supercritical state by venting a gaseous phase of the cryogen from another conditioning vessel into the storage vessel, wherein, during the venting of the gaseous phase, heat is transferred from the gaseous phase to the cryogen contained in the conditioning vessel. Alternatively or additionally, during step b), the cryogen contained in the conditioning vessel can be brought into the supercritical state by removing a portion of the cryogen from the conditioning vessel using the pressure build-up system, as in step c), heating it, and returning it to the conditioning vessel. Preferably, the heated cryogen is introduced into a liquid zone of the conditioning vessel.

[0024] The first-mentioned conditioning vessel can also be referred to as the first conditioning vessel. The second conditioning vessel can also be referred to as the second conditioning vessel. Furthermore, as previously mentioned, a third conditioning vessel can also be provided. "Blowing off" the gaseous phase of the cryogen is understood here to mean that the gaseous phase is passed from the respective conditioning vessel into the storage vessel. The gaseous phase can be introduced into a gas zone or a liquid zone of the storage vessel. The heat can be transferred from the gaseous phase to the cryogen contained in the respective conditioning vessel with the aid of a recuperator provided on the respective conditioning vessel.The gaseous phase is passed through this recuperator, which can be designed, for example, as a pipe coil, whereby the gaseous phase releases heat to the cryogen contained in the respective conditioning vessel. In the process, the gaseous phase cools and can partially condense. For example, the gaseous phase from the second conditioning vessel can be vented into the storage vessel. The gaseous phase from the second conditioning vessel releases heat to the cryogen contained in the first conditioning vessel in order to bring it into the supercritical state during step b). The reverse applies. With any number of conditioning vessels, this heat transfer can be carried out alternately.

[0025] According to a further embodiment, during the blow-off of the gaseous phase, the gaseous phase is expanded by means of a valve, in particular by means of a Joule-Thomson valve.

[0026] The valve is located downstream of the respective recuperator. During expansion, the gaseous phase can partially liquefy. The liquid phase is then fed into the storage vessel. By expanding the gaseous phase with the help of the valve, further heat can be extracted from the gaseous phase, which is then not introduced into the storage vessel. This further extends the cryogen's holding time.

[0027] According to a further embodiment, the conditioning container and the further conditioning container are operated intermittently.

[0028] In particular, the first conditioning vessel, the second conditioning vessel, and the third conditioning vessel are operated intermittently. If more than three conditioning vessels are provided, these are also operated intermittently. The intermittent operation of the conditioning vessels makes it possible to provide the consumer with a continuous volume flow of cryogen.

[0029] According to a further embodiment, during step c), heat is supplied to the cryogen enclosed in the volume between the valves by means of an external evaporator, in particular a water bath evaporator. The volume is preferably in heat-transfer communication with the external evaporator. Preferably, the at least one line is routed through the external evaporator, with a first valve arranged upstream of the evaporator and a second valve downstream of the evaporator. "External" in this case means, in particular, that the evaporator is not part of the conditioning vessel. In addition to supplying heat to the cryogen contained in the conditioning vessel, the evaporator can have other functions, such as heating the cryogen upstream of the consumer. The evaporator can thus be used multiple times. The evaporator is preferably filled with a heat transfer medium, in particular water.The heat transfer medium transfers heat to the portion of the cryogen that is removed from the conditioning vessel.

[0030] In the event that several conditioning containers are provided, a pressure build-up system is preferably assigned to each of the conditioning containers.

[0031] The pressure build-up system comprises at least one line and at least two valves. The line can exit directly from the conditioning tank or from a line leading from the conditioning tank to the consumer.

[0032] Preferably, the line passes through an external vaporizer. To return the heated cryogen to the conditioning vessel, the line reconnects to the conditioning vessel. The pressure buildup system may comprise a vessel connected to the conditioning vessel via lines. The vessel forms at least a portion of the volume in which the cryogen is enclosed for heating. The cryogen may be heated by means of a heating device in the vessel.

[0033] The pressure build-up system typically includes a pressure sensor. At least one line or container may be equipped with the pressure sensor.

[0034] As previously mentioned, the pressure build-up system has at least two valves. A first valve is arranged downstream of the conditioning tank, and a second valve is arranged downstream of the first valve, and thus upstream of the conditioning tank. The first valve can be a check valve, a non-return valve, or a switching valve. The second valve is preferably a switching valve. If the first valve is a switching valve, then a non-return valve is preferably additionally arranged upstream of the first valve. According to a further embodiment, the pressure build-up system is operated discontinuously. "Discontinuously" is understood here to mean, in particular, that the pressure build-up system is operated intermittently or in phases.

[0035] To operate the pressure build-up system, the first valve located downstream of the conditioning vessel can be opened first, while the second valve located downstream of the first valve is closed. The cryogen now flows into the volume of the pressure build-up system. The first valve can then be closed. The cryogen is now enclosed in the volume between the two valves. The pressure in the volume now rises because heat is added to the cryogen contained in the volume, preferably with the help of the external vaporizer. A possible desirable target pressure in the line is 14 bara to 20 bara. This means that the target pressure in the volume preferably corresponds at least to the operating pressure. The target pressure within the line can be sensed using the previously mentioned pressure sensors.Once the aforementioned target pressure in the volume is reached, both valves can be opened, and the heated cryogen flows from the volume back into the conditioning vessel. The check valve prevents backflow of the cryogen. Due to the high flow velocity of the cryogen through the upstream second valve and the lower density of the cryogen in the volume, cryogen flows from the conditioning vessel or from the line leading from the conditioning vessel to the consumer into the pressure build-up system volume via the check valve (if present) and the open downstream first valve. Once the pressure in the conditioning vessel and the pressure build-up volume have equalized, both valves can be closed again, and the aforementioned cycle can begin again. The pressure build-up system is thus operated intermittently.

[0036] The pressure build-up system is preferably operated exclusively by opening and closing the valves.

[0037] Pumps or other moving components are not required. This increases the operational reliability of the pressure build-up system. The pressure build-up system preferably comprises only the aforementioned line, the valves, the check valve, and the pressure sensors.

[0038] According to a further embodiment, after step a), the conditioning container is separated from the storage container by means of a valve by closing the valve.

[0039] Additionally, the conditioning tank can be separated from the consumer by means of another valve. Furthermore, after step a), the second conditioning tank or the third conditioning tank can also be separated from the storage tank by means of such a valve. The same applies to the consumer. The valve is preferably a shut-off valve. The valve can be an on-off valve. This means that the valve can be placed in two states, namely an open state and a closed state. The aforementioned valve is provided in or on the extraction line provided between the storage tank and the conditioning tank, or in or on the line branching off from the extraction line, which leads to another conditioning tank. Preferably, the valve provided between the conditioning tank and the consumer is opened in step c). This valve is closed during step b).Likewise, such a valve can be assigned to the second conditioning vessel and the third conditioning vessel. The valve is located downstream of the respective conditioning vessel. During step c), the density of the cryogen preferably decreases. While the density decreases, the cryogen is continuously maintained in the supercritical state, and the consumer is supplied with the cryogen. The decrease in density results from the cryogen being removed from the respective conditioning vessel during step c).

[0040] According to a further embodiment, an operating pressure within the conditioning container is kept constant during step c).

[0041] "Constant" in this case can be understood as a deviation from the operating pressure of ±1 bara. Preferably, the operating pressure within the respective conditioning vessel is maintained at 14 bara. This keeps the operating pressure above the critical pressure. Step e) is preferably terminated after a predetermined temperature is reached. The predetermined temperature is, for example, -230°C. After the predetermined temperature is reached, preferably no further heat is introduced into the respective conditioning vessel.

[0042] According to a further embodiment, in step c), the heated cryogen is introduced into a lower or upper part of the conditioning vessel. Preferably, the heated cryogen is introduced into a lower part of the conditioning vessel in order to resolve any temperature stratification of the cryogen that may have occurred within the conditioning tank. It is also possible to simultaneously introduce the heated cryogen into both the lower and upper parts of the conditioning vessel. This requires an additional line leading from the first-mentioned, at least one line, or from the vessel.

[0043] According to a further embodiment, after step c), the conditioning container is depressurized until a supply pressure of the consumer is reached.

[0044] In particular, the conditioning tank is released into the consumer. The supply pressure is, for example, 6 bara. By releasing the conditioning tank into the consumer, the conditioning tank can be further emptied.

[0045] According to a further embodiment, the conditioning tank is released into the storage tank once the supply pressure is reached.

[0046] This means that as soon as the pressure in the conditioning vessel drops below the supply pressure, the cryogen is no longer fed to the consumer but to the storage vessel. The cryogen is in gaseous form. Heat is then extracted from the gaseous phase during feeding to the storage vessel in order to heat the cryogen in one of the other conditioning vessels. For this purpose, recuperators, as previously mentioned, are provided. During feeding to the storage vessel, the cryogen can be introduced into the storage vessel either from above, i.e., into the gas zone of the storage vessel, from the side, or from below, i.e., into the liquid zone of the storage vessel. In the latter case, at least partial condensation of the gaseous phase in the storage vessel is possible.

[0047] Furthermore, a conveying device for conveying a cryogen from a storage container to a consumer is proposed. The conveying device comprises a first conditioning container arranged between the storage container and the consumer, wherein the first conditioning container is configured to convert cryogen introduced from the storage container into the first conditioning container into its supercritical state, to maintain the cryogen in the first conditioning container in its supercritical state while the cryogen is being supplied to the consumer, and to supply the cryogen to the consumer.According to the invention, the first conditioning vessel comprises a pressure build-up system configured to maintain the cryogen contained in the first conditioning vessel in the supercritical state while the cryogen is being supplied to the consumer. The pressure build-up system removes a portion of the cryogen from the first conditioning vessel, heats it, and returns it to the first conditioning vessel. According to the invention, the pressure build-up system comprises a volume, a first valve, and a second valve, between which the cryogen can be enclosed in the volume. The pressure build-up system is further configured, according to the invention, to supply heat to the cryogen enclosed in the volume and, as soon as a desired target pressure is reached in the volume, to return the cryogen to the first conditioning vessel.The volume can be formed by one line, by several lines or by a container that is connected to the conditioning container via lines.

[0048] The aforementioned method is carried out in particular with the aid of the conveying device according to the invention. The conveying device can have any number of such conditioning containers. Each conditioning container can be assigned such a pressure build-up system. However, the conveying device preferably has at least two conditioning containers. However, the conveying device can also have three, four, five or more than five conditioning containers. The storage container can be part of the conveying device. This is not absolutely necessary, however. As previously mentioned, the conditioning containers are preferably operated intermittently. The conveying device is particularly designed to convey the cryogen, as previously mentioned, from the storage container to the consumer by switching the valves of the conveying device accordingly.

[0049] According to one embodiment, the pressure build-up system preferably comprises an external evaporator, in particular a water bath evaporator, with which heat can be supplied to the cryogen enclosed in the volume. Preferably, the at least one line of the pressure build-up system is passed through the evaporator. The evaporator preferably accommodates a heat transfer medium in order to transfer heat to the portion of the cryogen enclosed between the valves in the volume, which the pressure build-up system previously removed from the conditioning vessel. The heat transfer medium preferably flows around the volume or the at least one line and thus transfers heat to the cryogen contained in the volume. As previously mentioned, this increases the pressure within the volume. This pressurized cryogen can then be fed back into the conditioning vessel.

[0050] Preferably, the at least one line opens into a lower part of the conditioning vessel in order to break up any temperature stratification that may have occurred in the conditioning vessel by introducing the heated cryogen. Alternatively or additionally, the at least one line can open into an upper part of the conditioning vessel.

[0051] According to a further embodiment, the conveying device comprises a second conditioning vessel, a recuperator provided on the first conditioning vessel, by means of which recuperator heat can be transferred to the cryogen located in the first conditioning vessel, and a line which leads from the second conditioning vessel via the recuperator to the storage vessel, so that a gaseous phase can be blown off from the second conditioning vessel into the storage vessel, wherein heat from the gaseous phase can be transferred via the recuperator to the cryogen accommodated in the first conditioning vessel.

[0052] The embodiments and features described for the method apply accordingly to the proposed conveying device, and vice versa. "One" is not necessarily to be understood as limiting the number of elements to exactly one. Rather, multiple elements, such as two, three, or more, can also be provided. Any other counting term used here should also not be understood as implying a precise limitation to the exact number of elements. Rather, numerical deviations upwards and downwards are possible.

[0053] Further possible implementations of the method and / or the conveying device 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 method and / or the conveying device.

[0054] Further advantageous embodiments of the method and / or the conveying device are the subject of the dependent claims and the exemplary embodiments of the method and / or the conveying device described below. The method and / or the conveying device are explained in more detail below using preferred embodiments with reference to the accompanying figures.

[0055] Fig. 1 shows a schematic view of an embodiment of a conveying device for conveying hydrogen;

[0056] Fig. 2 shows a pressure-enthalpy diagram of hydrogen; and

[0057] Fig. 3 shows a schematic block diagram of an embodiment of a method for producing hydrogen.

[0058] In the figures, identical or functionally equivalent elements have been given the same reference numerals unless otherwise stated.

[0059] Fig. 1 shows a schematic view of an embodiment of a conveying device 1 for conveying hydrogen H2. With the help of the conveying device 1, the hydrogen H2 can be conveyed from a storage container 2 to a consumer 3. The storage container 2 is particularly suitable for holding liquid hydrogen LH2. The storage container 2 is constructed rotationally symmetrically to a symmetry or central axis 4. The storage container 2 is part of the conveying device 1. Alternatively, the storage container 2 can also not be part of the conveying device 1. The conveying device 1 is designed to continuously supply the consumer 3 with gaseous hydrogen GH2 at a supply pressure of approximately 6 bara and a supply temperature of 10 to 25 °C, regardless of the sea state or other movements of the storage container 2. The conveying device 1 can be referred to as a hydrogen conveying device.

[0060] The storage vessel 2 can also be referred to as a storage tank. As previously mentioned, the storage vessel 2 is suitable for holding liquid hydrogen LH2 (boiling point 1 bara: 20.268 K = -252.882 °C). Therefore, the storage vessel 2 can also be referred to as a hydrogen storage vessel or a hydrogen storage tank. However, the storage vessel 2 can also be used for other cryogenic liquids. Examples of cryogenic fluids or liquids, or cryogens for short, in addition to the previously mentioned liquid hydrogen LH2, 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).

[0061] The storage container 2 comprises an inner container in which the hydrogen H2 is contained, and an outer container in which the inner container is arranged. The storage container 2 is thus double-walled. A gap is provided between the inner container and the outer container. A vacuum is applied to the gap. An insulating element or insulating element for thermal insulation of the inner container is arranged in the gap. The insulating element can be multi-layered. This means that the insulating element comprises a plurality of layers or plies. In particular, the insulating element is a so-called multilayer insulation (MLI).

[0062] Liquid hydrogen LH2 is contained in storage tank 2. As long as the hydrogen H2 is in the two-phase region, a gas zone 5 with gaseous hydrogen GH2 and a liquid zone 6 with liquid hydrogen LH2 can be provided in storage tank 2. Thus, after being filled into storage tank 2, the hydrogen H2 has two phases with different aggregate states, namely liquid and gaseous. This means that a phase boundary 7 exists in storage tank 2 between the liquid hydrogen LH2 and the gaseous hydrogen GH2.

[0063] Consumer 3 is preferably a fuel cell. A "fuel cell" is understood here to be a galvanic cell that converts the chemical reaction energy of a continuously supplied fuel, in this case hydrogen, and an oxidizing agent, in this case oxygen, into electrical energy.

[0064] The central axis 4 of the storage container 2 can be oriented perpendicular to a direction of gravity g. This means that the storage container 2 is positioned horizontally or horizontally. However, the storage container 2 can also be positioned vertically or vertically. In this case, the central axis 4 is oriented parallel to the direction of gravity g.

[0065] Particularly in maritime applications, movement of the liquid hydrogen LH2 stored in the storage tank 2 caused by sea waves must be expected. If the storage tank 2 is arranged horizontally, as shown in Fig. 1, the inertia of the liquid hydrogen LH2 and the curvature of the storage tank 2 caused by the horizontal installation promote extensive sloshing of the liquid hydrogen LH2 both on its cylindrical outer wall and at its ends.

[0066] This sloshing, also known as sloshing, leads to the cooling of the gaseous hydrogen GH2 above the liquid hydrogen LH2 and thus to an abrupt pressure drop in a gas cushion of gaseous hydrogen GH2 formed above the liquid hydrogen LH2. Depending on the current sea state, this can have adverse effects on the supply pressure available for the operating components of consumer 3, which can lead to unstable operation of consumer 3.

[0067] In order to provide the supply pressure for consumer 3, it is possible, according to internal experience, to use a liquid-cooled and liquid-bearing pump to pump the liquid hydrogen LH2. However, such a pump has moving parts. Furthermore, intermittent operation of the pump can lead to the formation of bubbles in the liquid hydrogen LH2 due to its heating. This can lead to a malfunction of the pump. Alternatively, the liquid hydrogen LH2 can be first evaporated and then brought to the required supply pressure using a compressor. However, this is energetically unfavorable.

[0068] Furthermore, the storage vessel 2 can also be operated directly at the supply pressure. In this case, an equilibrium is established in the storage vessel 2 between the liquid zone 6 and the gaseous zone 5 layered above it. However, due to the low surface tension of liquid hydrogen LH2, movement of the storage vessel 2 causes the liquid hydrogen LH2 and the gaseous hydrogen GH2 to mix with each other, causing the liquid hydrogen LH2 to cool the warmer gaseous hydrogen GH2. Maintaining the supply pressure is then not possible until equilibrium is again established between the temperature of the liquid hydrogen LH2 and the gaseous hydrogen GH2. This needs to be improved.

[0069] With the help of the conveying device 1, the aforementioned sloshing effects can be avoided or at least reduced. In addition to the storage container 2, the conveying device 1 comprises a first conditioning container 8, a second conditioning container 9, and a third conditioning container 10. The number of conditioning containers 8, 9, 10 is arbitrary. More than three or fewer than three conditioning containers 8, 9, 10 can be provided. However, it is assumed below that exactly three conditioning containers 8, 9, 10 are provided. Viewed along the direction of gravity g, the conditioning containers 8, 9, 10 are arranged below the storage container 2, so that the liquid hydrogen LH2 can flow from the storage container 2 into the conditioning containers 8, 9, 10 due to gravity. The conditioning containers 8, 9, 10 are operated intermittently or alternately, as will be explained below.

[0070] The conditioning tanks 8, 9, 10 are suitable for holding hydrogen H2.

[0071] The conditioning vessels 8, 9, 10 each comprise an inner vessel in which the hydrogen H2 is held, and an outer vessel in which the inner vessel is arranged. The conditioning vessels 8, 9, 10 are thus—like the storage vessel 2—double-walled. A gap is provided between the inner and outer vessels. A vacuum is applied to the gap. An insulating element or damping element is arranged in the gap to thermally insulate the inner vessel. The damping element can be multi-layered. This means that the damping element comprises a plurality of layers. In particular, the damping element is a so-called multilayer insulation (MLI).

[0072] A withdrawal line 11 leads from the storage tank 2 and to the consumer 3. A line 12 and a line 13 lead from the withdrawal line 11, both of which also lead to the consumer 3. A line 14 leads from line 12 and into the first conditioning tank 8. A line 15 leads from line 13 and into the second conditioning tank 9. A line 16 leads from the withdrawal line 11 and into the third conditioning tank 10.

[0073] A valve V1.1 is connected to line 12, located upstream of line 14. A valve V1.2 is connected to line 13, located upstream of line 15. A valve V1.3 is connected to the extraction line 11, located upstream of line 16. Valve V1.1 is assigned to the first conditioning tank 8. Valve V1.2 is assigned to the second conditioning tank 9. Valve V1.3 is assigned to the third conditioning tank.

[0074] 10. Downstream of line 14 branching off from line 12, a valve V4.1 is connected to line 12. Downstream of line 15 branching off from line 13, a valve V4.2 is connected to line 13. Downstream of line 16 branching off from extraction line 11, a valve V4.2 is connected to extraction line

[0075] 11 a valve V4.3 is switched.

[0076] The conveying device 1 further comprises an evaporator 17, in particular a water bath evaporator. The evaporator 17 is filled with a heat transfer medium H2O. The heat transfer medium H2O is water or a water-containing solution. However, the heat transfer medium H2O can also be any other heat transfer fluid. The heat transfer medium H2O can, for example, be a thermal oil or a molten salt. In particular, the heat transfer medium H2O is a liquid that does not undergo a phase change.

[0077] However, it is assumed below that the heat transfer medium H2O is water. Therefore, the heat transfer medium H2O is referred to below as water. The extraction line 11 and the lines 12, 13 are passed through the evaporator 17, in particular through the water H2O held in the evaporator 17, so that the extraction line 11 and the lines 12, 13 are flushed with water H2O. The consumer 3 is located downstream of the evaporator 17. An evaporator 18 is connected upstream of the consumer 3, with the aid of which the liquid hydrogen LH2 can be evaporated and supplied to the consumer 3 as gaseous hydrogen GH2. However, the evaporator 18 can be dispensed with if the liquid hydrogen LH2 can already be completely evaporated in the evaporator 17.

[0078] A line 19 leads out of the first conditioning tank 8. The line 19 is wound spirally around the inner tank of the third conditioning tank 10. This spiral geometry of the line 19 forms a third recuperator 20 provided on the third conditioning tank 10. The third recuperator 20 is thermally connected to the inner tank of the third conditioning tank 10. For example, a welded or soldered connection can be provided. The line 19 leads into the storage tank 2 above the phase boundary 7. A valve V3.1 is connected to the line 19. A line 21 branches off from the line 19 and leads into the storage tank 2 below the phase boundary 7. A valve V2.1 is connected to the line 21.

[0079] A line 22 leads out of the second conditioning tank 9. The line 22 is wound spirally around the inner container of the first conditioning tank 8. This spiral geometry of the line 22 forms a first recuperator 23 provided on the first conditioning tank 8. The first recuperator 23 is connected to the inner container of the first conditioning tank 8 in a heat-conducting manner. A welded or soldered connection can be provided, for example. A valve V3.2 is connected to the line 22. The line 22 opens into the line 19 and thus into the gas zone 5 of the storage tank 2. A line 24 leads out of the line 22 and opens into the line 21 downstream of the valve V2.1. A valve V2.2 is connected to the line 24.

[0080] A line 25 leads out of the third conditioning tank 10. The line 25 is wound spirally around the inner container of the second conditioning tank 9. This spiral geometry of the line 25 forms a second recuperator 26 provided on the second conditioning tank 9. The second recuperator 26 is thermally connected to the inner container of the second conditioning tank 9. For example, a welded or soldered connection can be provided. The line 25 leads into the line 19 and thus into the gas zone 5 of the storage tank 2. A valve V3.3 is connected into the line 25. A line 27 leads out of the line 25 upstream of the valve V3.3. The line 27 leads into the line 21 downstream of the valve V2.1. A valve V2.3 is connected into the line 27.

[0081] Each conditioning tank 8, 9, 10 is assigned a pressure build-up system 28, 29, 30. The first conditioning tank 8 is assigned a first pressure build-up system 28, the second conditioning tank 9 is assigned a second pressure build-up system 29, and the third conditioning tank 10 is assigned a third pressure build-up system 30. The pressure build-up systems 28, 29, 30 are structurally identical. Therefore, only the first pressure build-up system 28 and the first conditioning tank 8 will be discussed below. Therefore, the pressure build-up systems 29, 30 are only indicated in a very abstract manner in Fig. 1. All the following statements regarding the first pressure build-up system 28 and the first conditioning tank 8 are correspondingly applicable to the pressure build-up systems 29, 30 and to the conditioning tanks 9, 10.

[0082] With the aid of the first pressure build-up system 28, heat Q can be introduced into the first conditioning vessel 8, in particular into the hydrogen H2 held in the first conditioning vessel 8, in order to achieve a pressure build-up within the first conditioning vessel 8.

[0083] The first pressure build-up system 28 has a line 31 that emerges from line 12 between line 14 and valve V4.1. Line 31 passes through the evaporator 17 and opens into an upper part 8.1 of the conditioning vessel 8, preferably at a topmost point (relative to the direction of gravity) in the first conditioning vessel 8. This means, in particular, that line 31 can open into a gas zone provided in the first conditioning vessel 8. Line 31 can emerge directly from the first conditioning vessel 8, from line 14, or downstream of line 14 from line 12.

[0084] Downstream of line 12 and upstream of evaporator 17, a non-return valve 32 is preferably connected to line 31. Downstream of the non-return valve 32, a valve V5.1 is connected to line 31. Valve V5.1 can be referred to as the first valve of the first pressure build-up system 28. Valve V5.1 is thus positioned between the optional non-return valve 32 and evaporator 17. Immediately upstream of first conditioning tank 8, a valve V6.1 is connected to line 31. Valve V6.1 can be referred to as the second valve of the first pressure build-up system 28. Upstream of valve V6.1, a line 33 issues from line 31. Line 33 also leads to first conditioning tank 8. Line 33 preferably issues into a lower part 8.1 of first conditioning tank 8.Viewed along the direction of gravity g, the line 33 according to the present exemplary embodiment opens below the line 31 into the first conditioning tank 8. This means, in particular, that the line 33 can open into a liquid zone provided in the first conditioning tank 8. A valve V7.1 is connected into the line 33. The valve V7.1 can be referred to as the third valve of the first pressure build-up system 28. Deviating from the illustrated embodiment, the line 31 can also open into the lower part 8a of the first conditioning tank, and the line 33, which branches off from the line 31, can open into the upper part 8b of the conditioning tank.

[0085] A pressure sensor 34 and a temperature sensor 35 are assigned to the first conditioning tank 8. With the help of the pressure sensor 34 and the temperature sensor 35, it is possible to detect a pressure and a temperature within the first conditioning tank 8. Furthermore, a further pressure sensor 36, which is attached to the line 31, is assigned to the first conditioning tank 8. The pressure sensors 34, 36 and the temperature sensor 35 can be part of the first pressure build-up system 28. At least the pressure sensor 36 is part of the first pressure build-up system 28. The pressure sensors 34, 36 can have any number of pressure sensors or pressure transducers that are attached in or on the first conditioning tank 8 and / or in or on the line 31. The temperature sensor 35 can have any number of temperature sensors or temperature transducers that are attached in and / or on the first conditioning tank 8.

[0086] The conditioning tanks 9, 10 are each also assigned a pressure sensor 34 and a temperature sensor 35, although these are not shown in Fig. 1. The storage tank 2 can also be assigned a pressure sensor 34 and a temperature sensor 35, although these are also not shown in Fig. 1. The conveying device 1 comprises a control and regulation unit 37, which is operatively connected to the pressure sensors 34, 36 and / or the temperature sensor 35. The operative connection can be wireless or wired. The control and regulation unit 37 can control the valves V1.1, V1.2, V1.3, V2.1, V2.2, V2.3, V4.1, V4.2, V4.3, V4.1, V5.1, V6.1, V7.1. In other words, the control unit 37 can selectively open or close the valves V1.1, V1.2, V1.3, V2.1, V2.2, V2.3, V4.1, V4.2, V4.3, V4.1, V5.1, V6.1, V7.1. This can be done based on sensor signals from the pressure sensors 34, 36 and / or the temperature sensors 35. The valves V1.1, V1.2, V1.3, V2.1, V2.2, V2.3, V4.1, V4.2, V4.3, V4.1, V5.1, V6.1, V7.1 are preferably switching valves. Valve V5.1 of the pressure build-up system 28 can also be a check valve or a non-return valve. The optional non-return valve 32 is preferably present if valve V5.1 is a switching valve.

[0087] Figure 2 shows a pressure-enthalpy diagram of hydrogen H2.

[0088] The functionality of the conveying device 1 is explained below using the pressure-enthalpy diagram shown in Fig. 2. A pressure-enthalpy diagram is a state diagram with the specific enthalpy h on the abscissa axis and the pressure p on the ordinate axis. Fig. 2 shows a log-pH diagram which scales the pressure p logarithmically. In Fig. 2, a denotes the two-phase region in which the gaseous hydrogen GH2 and the liquid hydrogen LH2 are present simultaneously. The pure gas phase of the hydrogen H2 is denoted by b. The supercritical region is denoted by c. The pure liquid phase of the hydrogen H2 is denoted by d. In Fig. 2, the two-phase line 38 with the critical point Pc is drawn. In thermodynamics, the critical point Pc is a thermodynamic state of a substance, in this case hydrogen H2, which is characterized by the equalization of the densities of the liquid phase and the gaseous phase.The differences between the two states of matter cease to exist at the critical point Pc. Hydrogen H2 is then in its supercritical state. At the critical point Pc, hydrogen H2 has a critical pressure pc of 12.3 bara and a critical temperature Tc of -239.9 °C.

[0089] Both gaseous hydrogen GH2 and liquid hydrogen LH2 are present in storage tank 2. The first conditioning tank 8 initially contains gaseous hydrogen GH2. The gaseous hydrogen GH2 is expanded into storage tank 2 via line 19. For this purpose, valve V3.1, which can be a Joule-Thomson valve, is opened. The gaseous hydrogen GH2 can be liquefied at valve V3.1. The gaseous hydrogen GH2 or liquid hydrogen LH2 is fed to gas zone 5 via line 19.

[0090] At least the valves V1.1, V2.1, V3.2, V3.3, and V4.1 are closed. When the first conditioning tank 8 is depressurized, heat Q from the gaseous hydrogen GH2 flowing through line 19 and the third recuperator 20 can be transferred to the third conditioning tank 10 with the aid of the third recuperator 20.

[0091] Alternatively, valve V3.1 can be closed and valve V2.1 open. In this case, the gaseous hydrogen GH2 is introduced into liquid zone 6 via lines 19, 21. In this case, valves V2.2, V2.3 are also closed. The liquid hydrogen LH2 in storage tank 2 then cools the supplied gaseous hydrogen GH2, causing it to at least partially condense.

[0092] Subsequently, the first conditioning vessel 8 is filled with liquid hydrogen LH2 via the extraction line 11 and the line 12. For this purpose, at least the valves V1.2, V1.3, V2.1, V4.1, V5.1 are closed and the valve V1.1 is open. The valve V3.1 is also open for gas equalization. Since the storage vessel 2 is positioned above the first conditioning vessel 8 with respect to the direction of gravity g, the liquid hydrogen LH2 flows independently into the first conditioning vessel 8 due to the static pressure. For example, the liquid hydrogen LH2 in the storage vessel 2 or in the first conditioning vessel 8 at a point A has an initial pressure p1 of 1 bara, a temperature λ of -253 °C, and a density Q of 71 kg / m 3Point A is an intersection point of the two-phase line 38 with a 1-bar line 39. At point A, the same outlet pressure p1 prevails in the storage tank 2 and in the first conditioning tank 8.

[0093] The first conditioning vessel 8 is then isolated from the storage vessel 2 by closing valve V1.1. The valves V2.1, V3.1, V4.1, V5.1 are closed. With the help of the first recuperator 23, heat Q is introduced into the liquid hydrogen LH2 contained in the first conditioning vessel 8 in order to increase the pressure p in the first conditioning vessel 8. This is illustrated in Fig. 2 by a transition from point A to point B. At point B, the operating pressure p2 is 14 bara, the temperature T is -251 °C, and the density Q is 71 kg / m 3This means that the operating pressure p2 is higher than the critical pressure pc. The transition from point A to point B can be referred to as conditioning or the conditioning process.

[0094] The temperature T has risen by 2 °C during the transition from point A to point B. The hydrogen H2 in the first conditioning tank 8 is now in the supercritical state. Since no phase boundary 7 exists in the supercritical state of the hydrogen H2, movements of the first conditioning tank 8, for example during rough seas, have no undesirable effects. The hydrogen H2 in the supercritical state from the first conditioning tank 8 can now be fed to the consumer 3, with evaporation taking place upstream of the consumer 3 with the aid of the evaporator 17 and / or the evaporator 18.

[0095] In order to supply consumer 3 with hydrogen H2 from the first conditioning tank 8, valves V1.1, V2.1, V3.1 remain closed and valve V4.1 is opened. Valves V5.1, V6.1, V7.1 of the first pressure build-up system 28 are selectively opened or closed to achieve pressure control such that when the hydrogen H2 is withdrawn from the first conditioning tank 8, the operating pressure p2 can be kept constant, so that the hydrogen H2 remains in its supercritical state even when it is withdrawn from the first conditioning tank 8. This is shown in Fig. 2 by a transition from point B to point C. This previously explained pressure control with the aid of the first pressure build-up system 28 will be explained in more detail below.

[0096] From point B to point C, the operating pressure p2 is preferably maintained exclusively with the aid of the first pressure build-up system 28. For this purpose, the valve V5.1 is opened while the valves V6.1, V7.1 remain closed. Hydrogen H2 flows from the line 12 into the line 31. The valve V5.1 is then closed. The hydrogen H2 is now enclosed between the valves V5.1, V6.1, V7.1 in the line 31. The pressure in the line 31 rises because heat Q is added to the hydrogen H2 taken up in the line 31 with the aid of the evaporator 17. A possible desirable target pressure in the line 31 is 14 bara to 20 bara. This means that the target pressure in the line 31 corresponds at least to the operating pressure p2. The pressure within the line 31 can be sensed using the pressure sensor 36.

[0097] As soon as the aforementioned target pressure in line 31 is reached, valves V5.1, V6.1 are opened and the hydrogen H2 flows from line 31 into the first conditioning vessel 8. Alternatively, valve V6.1 can remain closed and valve V7.1 can be opened. The check valve 32 prevents a backflow of the hydrogen H2 from line 31 into line 12. Due to the high flow velocity of the hydrogen H2 through valve V6.1 and the lower density Q of the hydrogen H2 in line 31, hydrogen H2 flows from line 12 into line 31 via the optional check valve 32 and the open valve V5.1. As soon as the pressure in the first conditioning vessel 8 and in line 31 have equalized, valves V5.1, V6.1 are closed again and the aforementioned cycle begins again. The first pressure build-up system 28 is thus operated intermittently or discontinuously.

[0098] With the help of evaporator 17 and / or evaporator 18, the hydrogen H2 is evaporated and brought to a supply pressure p3 for consumer 3 of approximately 6 bara at a temperature T of 10 to 25 °C. Upstream of evaporator 18, heat Q is introduced into line 12 with the help of evaporator 17, so that the heat output of evaporator 18 is reduced and it can thus at least be made smaller. However, evaporator 18 can also be completely dispensed with.

[0099] The initial filling of the first conditioning tank 8 is solely a function of the temperature T. A fill level measurement is unnecessary. As previously mentioned, the hydrogen H2 is delivered to the consumer 3 by opening the valve V4.1. The pressure p in the first conditioning tank 8 is simultaneously maintained at a pressure p of 14 bara, in particular at the operating pressure p2, by further supplying heat Q, preferably with the aid of the first pressure build-up system 28 and optionally additionally with the aid of the first recuperator 23. The fill level of the first conditioning tank 8 is purely a function of the temperature T.

[0100] During the emptying and simultaneous heating of the first conditioning vessel 8, the density Q of the hydrogen H2 in the first conditioning vessel 8 decreases. The hydrogen H2 remains in the supercritical state. This is illustrated in Fig. 2 by the transition from point B to point C. At point C, the operating pressure p2 remains 14 bara, the temperature T is -230 °C, and the density Q is 9.8 kg / m 3 During the transition from point B to point C, valve V4.1 remains open. From point B to point C, the two-phase region a is not crossed.

[0101] The temperature T is chosen such that a significant drop in density Q occurs between points B and C. This allows for maximum utilization of the hydrogen H2. The temperature T reached at point C is a compromise between maximum utilization of the hydrogen H2 and heat input into the storage tank 2. When a certain temperature T is reached, the transfer of the hydrogen H2 to the consumer 3 is stopped. The temperature T is maintained, and a certain pressure drop is allowed to further empty the first conditioning tank 8.

[0102] Alternatively, the introduction of heat Q can be stopped in order to reduce the temperature T in the first conditioning vessel 8 by expanding the supercritical hydrogen H2. This allows for maximum utilization of the hydrogen H2. This is illustrated in Fig. 2 by a transition from point C to point D. At point D, the hydrogen H2 has a supply pressure p3 of 6 bara, a temperature α of -242 °C, and a density Q of 6.2 kg / m 3 At point D, valve V4.1 is closed, and the hydrogen H2 is released into storage tank 2, as explained above. A hydrogen H2 utilization rate of 92% can be achieved. The release occurs from point D to point A.

[0103] As previously mentioned, the conditioning vessels 8, 9, 10 are operated intermittently. While the hydrogen H2 is withdrawn from the first conditioning vessel 8 and supplied to the consumer 3, the second conditioning vessel 9 is conditioned, as previously explained with reference to the first conditioning vessel 8. The hydrogen H2 in the second conditioning vessel 9 is thus transported from point A to point B in order to reach the supercritical state. The valves V1.2, V2.2, V3.2, V4.2 are closed. At the same time, the third conditioning vessel 10 is filled with liquid hydrogen LH2 from the storage vessel 2, as previously explained with reference to the first conditioning vessel 8. For this purpose, the valves V1.3, V3.3 are open, whereas the valves V1.1, V1.2, V2.3, V3.1, V3.2, V4.3 are closed.

[0104] As soon as the first conditioning tank 8 is emptied and is at point D, the hydrogen H2 still in the first conditioning tank 8 is released into the storage tank 2 via line 19. Valves V1.1, V4.1, and V5.1 are closed for this purpose. One of valves V2.1 and V3.1 is open. The hydrogen H2 flows through the third recuperator 20 and releases heat Q to the hydrogen H2 located in the third conditioning tank 10. This means that the hydrogen H2 in the third conditioning tank 10 is conditioned from point A to point B with the help of the heat Q from the third recuperator 20.

[0105] Meanwhile, the second conditioning tank 9 supplies hydrogen H2 to the consumer 3, as previously explained with reference to the first conditioning tank 8. The valves V1.2, V2.2, V3.3 are closed. The valve V4.2 is open, and the second pressure build-up system 29 maintains the second conditioning tank 9 at the operating pressure p2, as previously explained with reference to the first conditioning tank 8 and the first pressure build-up system 28. While the first conditioning tank 8 is depressurized and the second conditioning tank 9 is emptied, the third conditioning tank 10 is conditioned. During this process, the valves V1.3, V2.3, V3.3, V4.3 are closed. With the help of the third recuperator 20, heat Q is introduced into the third conditioning tank 10 in order to achieve the operating pressure p2 therein.

[0106] As soon as the first conditioning vessel 8 is relieved of pressure again, it is refilled. Valves V1.1 and V3.1 are open for this purpose. Liquid hydrogen LH2 flows from the storage vessel 2 into the first conditioning vessel 8. When the first conditioning vessel 8 is filled, the same outlet pressure p1 prevails in the storage vessel 2 and the first conditioning vessel 8. Meanwhile, the second conditioning vessel 9 continues to supply the consumer 3 with hydrogen H2, with the second pressure build-up system 29 keeping the operating pressure p2 in the second conditioning vessel 9 constant. The third conditioning vessel 10 is filled and conditioned. The hydrogen H2 in the third conditioning vessel 10 is supercritical. Valves V1.3, V2.3, V3.3 and V4.3 are closed. The third conditioning vessel 10 is now ready to supply the consumer 3 with hydrogen H2 as soon as the second conditioning vessel 9 is emptied and reaches point D.

[0107] As previously explained, the conveying device 1 can have any number of conditioning tanks 8, 9, 10. The conditioning tanks 8, 9, 10 are then operated in such a way that hydrogen H2 for the consumer 3 can always be withdrawn from one of the conditioning tanks 8, 9, 10. A continuous supply to the consumer 3 is then possible.

[0108] The advantages of the conveying device 1 are summarized below. The hydrogen H2 in the storage vessel 2 can be kept at equilibrium, resulting in a long holding time for the hydrogen H2. It is sufficient to use conventional bulkheads or walls to prevent sloshing for mechanical reasons only. This allows the storage vessel 2 to be constructed more lightly. This results in a higher absorption capacity for the hydrogen H2. The storage vessel 2 can be operated in a suitable pressure range of 1 to 6 bara. The density Q of saturated liquid hydrogen LH2 is pressure-dependent. It is desirable to operate the storage vessel 2 at the lowest possible pressure p. For example, the density Q is 71 kg / m 3 at a pressure p of 1 bara, 60 kg / m 3 at a pressure p of 6 bara and 28 kg / m 3at a pressure p of 12 bara. With the exception of the valves V1.1, V1.2, V1.3, V2.1, V2.2, V2.3, V3.1, V3.2, V3.3, V4.1, V4.2, V4.3, V5.1, V6.1, V7.1, and the check valve 32, the conveying device 1 has no moving parts. The conveying device 1 is therefore very resistant to failure.

[0109] The hydrogen H2 in the conditioning vessels 8, 9, 10 can be kept in equilibrium. Walls or bulkheads to prevent sloshing are only required if the conditioning vessels 8, 9, 10 are operated at a pressure p of less than 0.8*pc, preferably less than 0.9*pc. The hydrogen H2 can be extracted from the conditioning vessels 8, 9, 10 as a single-phase medium, namely in the supercritical state. The conveying device 1 can also be used under harsh conditions, for example, in heavy seas, since no phase transition can occur between the gas phase and the liquid phase, which could lead to disrupted operation of the consumer 3.

[0110] Stable and trouble-free operation of consumer 3 is possible because the hydrogen H2 can be extracted from the conditioning tanks 8, 9, 10 as a single-phase medium. Level control of the conditioning tanks 8, 9, 10 is unnecessary because, for example, a stop temperature can be set at point C, at which the supply to consumer 3 is stopped. Because it is possible to introduce the gaseous hydrogen GH2 directly into the liquid hydrogen LH2 via line 21, equilibrium can be quickly achieved in the storage tank 2.

[0111] By extracting heat Q from the gaseous hydrogen GH2 with the aid of recuperators 20, 23, 26 and using it for conditioning, the heat Q input into storage tank 2 is reduced. The holding time of storage tank 2 is thereby increased. In recuperators 20, 23, 26, the gaseous hydrogen GH2 can at least partially condense. The gaseous hydrogen GH2 can be further cooled or condensed using valves V3.1, V3.2, and V3.3, which are preferably designed as Joule-Thomson valves.

[0112] This further reduces the input of heat Q into the storage tank 2.

[0113] Fig. 3 shows a schematic block diagram of an embodiment of a method for conveying hydrogen H2.

[0114] The process is carried out using the conveying device 1. Hydrogen H2 is conveyed from the storage tank 2 to the consumer 3. In step S1, the hydrogen H2 is introduced from the storage tank 2 into one of the conditioning tanks 8, 9, 10. This occurs purely by gravity due to the hydrostatic pressure of the liquid hydrogen LH2 in the storage tank 2.

[0115] In a step S2, the hydrogen H2 contained in the respective conditioning tank 8, 9, 10 is converted or brought into its supercritical state. This can be achieved by adding heat Q

[0116] In a step S3, the hydrogen H2 is discharged or conveyed from the respective conditioning vessel 8, 9, 10 to the consumer 3. The hydrogen H2 held in the respective conditioning vessel 8, 9, 10 is maintained in the supercritical state during step S3 by removing a portion of the hydrogen H2 held in the respective conditioning vessel 8, 9, 10 using a respective pressure build-up system 28, 29, 30, heating it, and then returning it to the corresponding conditioning vessel 8, 9, 10.

[0117] As previously mentioned, during step S1, the hydrogen H2 flows from the storage tank 2 into the respective conditioning tank 8, 9, 10 only due to its hydrostatic pressure, in particular the hydrostatic pressure of the liquid hydrogen LH2.

[0118] In step S2, the hydrogen H2 is brought into the supercritical state by blowing off the gaseous hydrogen GH2 from one of the conditioning vessels 8, 9, 10 into the storage vessel 2, wherein during the blowing off of the gaseous hydrogen GH2, heat Q is transferred from the gaseous hydrogen GH2 to the hydrogen H2 held in one of the other conditioning vessels 8, 9, 10. For this purpose, the conditioning vessels 8, 9, 10 have the recuperators 20, 23, 26. During the blowing off of the gaseous hydrogen GH2, this can be expanded using one of the valves V3.1, V3.2, V3.3. As previously mentioned, the conditioning vessels 8, 9, 10 are operated intermittently during the process.Alternatively or additionally, it is also possible to introduce the heat Q into the respective conditioning vessel 8, 9, 10 using the respective pressure build-up system 28, 29, 30 in order to convert the absorbed cryogen (H2) into its supercritical state in step S2. In this case, the heated cryogen is preferably introduced via line 33 into a liquid zone of the respective conditioning vessel 8, 9, 10, i.e., preferably into a lower part of the respective conditioning vessel 8, 9, 10.

[0119] The portion of hydrogen H2 that is withdrawn from the respective conditioning vessel 8, 9, 10 during step S3, heated, and returned is preferably supplied with heat Q using the external evaporator 17, particularly in the form of a water bath evaporator. "External" means that the evaporator 17 is not part of one of the conditioning vessels 8, 9, 10. The evaporator 17 can therefore have multiple functions. The evaporator 17 can be spatially separated from the conditioning vessels 8, 9, 10. Only the line 31 of the respective pressure buildup system 28, 29, 30 passes through the evaporator 17.

[0120] During step S3, the portion of hydrogen H2 that is withdrawn from the respective conditioning vessel 8, 9, 10, heated, and then returned to the respective conditioning vessel 8, 9, 10 is withdrawn and returned to the respective conditioning vessel 8, 9, 10 using the respective pressure buildup system 28, 29, 30. The pressure buildup systems 28, 29, 30 are operated discontinuously. The pressure buildup systems 28, 29, 30 are operated exclusively by opening and closing the valves V5.1, V6.1, V7.1.

[0121] After step S1, the respective conditioning vessel 8, 9, 10 is separated from the storage vessel 2 with the aid of the respective valve V1.1, V1.2, V1.3 by closing the corresponding valve V1.1, V1.2, V1.3. The valves V4.1, V4.2, V4.3 are also selectively closed in order to separate the corresponding conditioning vessel 8, 9, 10 from the consumer 3. During step S3, the operating pressure p2 within the conditioning vessel 8, 9, 10 from which the hydrogen H2 is taken and supplied to the consumer 3 is kept constant. After step S3, the corresponding conditioning vessel 8, 9, 10 is depressurized until the supply pressure p3 of the consumer 3 is reached. The corresponding conditioning vessel 8, 9, 10 is depressurized into the storage vessel 2 once the supply pressure p3 is reached.

[0122] Deviating from the embodiments illustrated in Figures 1 to 3 and described above, the pressure build-up systems 28, 29, 30 can also each comprise a container connected via lines to the respective conditioning container 8, 9, and 10. The container provides the volume in which the cryogen removed from the respective conditioning container 8, 9, and 10 in step S3 is heated by means of a heater, for example, an electric heating element. The container with the heater can therefore represent an alternative to the external evaporator 17 illustrated in Fig. 1, through which the line 31 is routed.

[0123] Although the present invention has been described using exemplary embodiments, it can be modified in many ways.

[0124] Reference symbols used

[0125] 1 conveyor device

[0126] 2 storage tanks

[0127] 3 consumers

[0128] 4 Central axis

[0129] 5 Gas zone

[0130] 6 Liquid zone

[0131] 7 Phase boundary

[0132] 8 conditioning tanks

[0133] 8a lower part of the conditioning tank

[0134] 8b upper part of the conditioning tank

[0135] 9 conditioning tanks

[0136] 10 conditioning tanks

[0137] 11 Withdrawal line

[0138] 12 Line

[0139] 13 Management

[0140] 14 Line

[0141] 15 Line

[0142] 16 Line

[0143] 17 evaporators

[0144] 18 evaporators

[0145] 19 Management

[0146] 20 Recuperator

[0147] 21 Line

[0148] 22 Line

[0149] 23 Recuperator

[0150] 24 line

[0151] 25 Line

[0152] 26 Recuperator

[0153] 27 Line

[0154] 28 Pressure build-up system

[0155] 29 Pressure build-up system

[0156] 30 Pressure build-up system

[0157] 31 Line 32 Check valve

[0158] 33 Line

[0159] 34 Pressure sensors

[0160] 35 Temperature sensors

[0161] 36 Pressure sensors

[0162] 37 Control and regulation unit

[0163] 38 Two-phase line

[0164] 39 1-bar line a two-phase region

[0165] A point b gas phase

[0166] B Point c supercritical area

[0167] C Point d Liquid phase

[0168] D Point g Direction of gravity

[0169] GH2 gaseous hydrogen / gaseous phase h enthalpy

[0170] H2 Hydrogen / Cryogen

[0171] H2O water / heat transfer medium

[0172] LH2 liquid hydrogen / liquid phase p pressure pc critical pressure

[0173] Pc critical point p1 outlet pressure p2 operating pressure p3 supply pressure

[0174] Q Heat

[0175] 51 steps

[0176] 52 steps

[0177] 53 steps

[0178] V1.1 Valve

[0179] V1.2 Valve V1.3 Valve

[0180] V2.1 valve

[0181] V2.2 valve

[0182] V2.3 Valve V3.1 Valve

[0183] V3.2 valve

[0184] V3.3 Valve

[0185] V4.1 Valve

[0186] V4.2 Valve V4.3 Valve

[0187] V5.1 Valve

[0188] V6.1 valve

[0189] V7.1 Valve

Claims

Patent claims 1 . Method for conveying a cryogen (H2) from a storage container (2) to a consumer (3), comprising the following steps: a) introducing (S1) the cryogen (H2) from the storage container (2) into a conditioning container (8, 9, 10), b) bringing (S2) the cryogen (H2) received in the conditioning container (8, 9, 10) into its supercritical state, and c) discharging (S3) the cryogen (H2) from the conditioning container (8, 9, 10) to the consumer (3), wherein the cryogen (H2) received in the conditioning container (8, 9, 10) is kept in the supercritical state during step c), characterized in that during step c) the cryogen (H2) received in the conditioning container (8, 9, 10) is kept in the supercritical state by supplying the conditioning container (8, 9, 10) a portion of the cryogen (H2) is removed, heated and returned to the conditioning vessel (8, 9, 10), wherein the conditioning vessel (8, 9,10) the cryogen (H2) is removed and reinserted with the aid of a pressure build-up system (28, 29, 30), wherein the cryogen is received in a volume (31, 33) of the pressure build-up system (28, 29, 30) and enclosed in the volume between valves (V5.1, V6.1; V5.1, V7.1), heat is supplied to the enclosed cryogen, and as soon as a desired target pressure of the enclosed cryogen is reached, the cryogen is returned to the conditioning vessel (8, 9, 10).

2. The method according to claim 1, wherein during step b) the cryogen (H2) is brought into the supercritical state by blowing off a gaseous phase (GH2) of the cryogen (H2) from a further conditioning vessel (8, 9, 10) into the storage vessel (2), wherein during the blowing off of the gaseous phase (GH2) heat (Q) is transferred from the gaseous phase (GH2) to the cryogen (H2) received in the conditioning vessel (8, 9, 10).

3. The method according to claim 2, wherein during the blowing off of the gaseous phase (GH2) the gaseous phase (GH2) is expanded by means of a valve (V3.1, V3.2, V3.3), in particular by means of a Joule-Thomson valve.

4. The method according to any one of claims 1-3, wherein in step c) heat (Q) is supplied to the enclosed cryogen by means of an external evaporator (17), in particular a water bath evaporator (17).

5. Method according to one of claims 1 - 4, wherein the pressure build-up system (28, 29, 30) is operated discontinuously.

6. Method according to one of claims 1 - 5, wherein the pressure build-up system (28, 29, 30) is operated exclusively by opening and closing the valves (V5.1; V6.1, V7.1).

7. The method according to any one of claims 1-6, wherein in step c) the heated cryogen is introduced into a lower and / or an upper part (8.1) of the conditioning container (8, 9, 10).

8. The method according to any one of claims 1-7, wherein during step b) the cryogen (H2) held in the conditioning vessel (8, 9, 10) is brought into the supercritical state by removing a portion of the cryogen (H2) from the conditioning vessel (8, 9, 10) as in step e) with the aid of the pressure build-up system (28, 29, 30), heating it, and feeding it back into the conditioning vessel (8, 9, 10).

9. The method according to claim 8, wherein the heated cryogen is introduced into a liquid zone of the conditioning vessel (8, 9, 10).

10. Conveying device (1) for conveying a cryogen (H2) from a storage container (2) to a consumer (3), with a first conditioning container (8) arranged between the storage container (2) and the consumer (3), wherein the first conditioning container (8) is designed to convert cryogen (H2) introduced from the storage container (2) into the conditioning container (8) into to put it into a supercritical state, to keep the cryogen in the conditioning vessel (8, 9, 10) in its supercritical state while supplying the cryogen (H2) to the consumer (3), and to supply the cryogen to the consumer (3), characterized in that the first conditioning vessel (8) has a pressure build-up system (28) which is designed to keep the cryogen (H2) held in the first conditioning vessel (8) in the supercritical state while supplying the cryogen (H2) to the consumer (3) in that the pressure build-up system (28, 29, 30) removes a portion of the cryogen (H2) from the first conditioning vessel (8, 9, 10), heats it up and supplies it back to the first conditioning vessel (8, 9, 10), the pressure build-up system (28) has a volume (31, 33), a first valve (V5.1) and a second valve (V6.1 ; V7.1), between which the cryogen can be enclosed in the volume (31, 33), and the pressure build-up system (28) is designed to supply heat (Q) to the cryogen enclosed in the volume (31, 33) and, as soon as a desired target pressure in the volume (31, 33) is reached, to supply the cryogen back to the first conditioning container (8).

11. Conveying device according to claim 10, wherein the volume is formed by a line (31; 31, 33), by several lines (31, 33), or by a container which is connected to the first conditioning container (8) via lines.

12. Conveying device according to claim 10 or 11, wherein the pressure build-up system (28) has an external evaporator (17), in particular a water bath evaporator, with which the heat (Q) can be supplied to the cryogen enclosed in the volume (31, 33).

13. Conveying device according to claim 12, wherein the line (31) or lines is or are passed through the evaporator (17).

14. Conveying device according to one of claims 11 - 13, wherein the line (31, 33) or the lines (31, 33) open into a lower part (8.1) and / or into an upper part (8.1) of the first conditioning container (8).

15. Conveying device according to one of claims 10 - 14, comprising a second conditioning container (9), a recuperator (32) provided on the first conditioning container (8), by means of which recuperator heat can be transferred to the cryogen in the first conditioning container (9), a line (19, 22) which leads from the second conditioning container (8) via the recuperator (32) to the storage container (2) so that a gaseous phase (GH2) can be blown off from the second conditioning container (9) into the storage container (2), wherein heat (Q) from the gaseous phase (GH2) can be transferred via the recuperator (32) to the cryogen (H2) held in the first conditioning container (8).

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