METHOD AND SYSTEM FOR THE MATERIAL UTILIZATION OF HYDROGEN

Abstract

A method for the use of hydrogen as a resource includes producing a mixture by a catalytic reaction in a reactor. The mixture includes hydrogen carrier medium to which hydrogen can be chemically bound by a catalytic hydrogenation reaction and from which hydrogen can be released again by a catalytic dehydrogenation reaction, and hydrogen that is dissolved, i.e. physically stored, therein, and hydrogenating the hydrogen carrier medium with the dissolved hydrogen in a hydrogenation unit.

Claims

1. A method for the use of hydrogen as a resource, the method comprising the steps of producing a mixture by means of a catalytic reaction in a reactor wherein the mixture comprises hydrogen carrier medium to which hydrogen can be chemically bound by a catalytic hydrogenation reaction and from which hydrogen can be released again by a catalytic dehydrogenation reaction, and additionally hydrogen that is dissolved, i.e. physically stored, in the hydrogen carrier medium, hydrogenation of the hydrogen carrier medium with the dissolved hydrogen in a hydrogenation unit.

2. The method according to claim 1, wherein in that the hydrogenation in the hydrogenation unit takes place by means of a hydrogenation catalyst.

3. The method according to claim 1, wherein the hydrogenation takes place in the hydrogenation unit before the mixture from the reactor is depressurized.

4. The method according to claim 1, wherein the mixture is produced by hydrogenating the hydrogen carrier medium in a primary hydrogenation reactor that is located upstream of the hydrogenation unit.

5. The method according to claim 4, wherein the hydrogenation takes place in the hydrogenation unit before the mixture from the reactor is cooled.

6. The method according to claim 1, wherein the mixture is produced by dehydrogenating the hydrogen carrier medium in a primary dehydrogenation reactor that is located upstream of the hydrogenation unit.

7. The method according to claim 5, further comprising alternating hydrogenation and dehydrogenation of the hydrogen carrier medium in a circulation process, wherein hydrogenation of the hydrogen carrier medium with the physically dissolved hydrogen takes place in the hydrogenation unit in each case between the hydrogenation in the primary hydrogenation reactor and the dehydrogenation in the primary dehydrogenation reactor.

8. A system for the use of hydrogen as a resource, the system comprising at least one reactor for producing a mixture by means of a catalytic reaction, wherein the mixture comprises hydrogen carrier medium to which hydrogen can be chemically bound by a catalytic hydrogenation reaction and from which hydrogen can be released again by a catalytic dehydrogenation reaction, and additionally hydrogen that is dissolved, i.e. physically stored, in the hydrogen carrier medium, a hydrogenation unit that is in fluid communication with the reactor for hydrogenating the hydrogen carrier medium with the dissolved hydrogen.

9. The system according to claim 8, wherein the hydrogenation unit is arranged downstream of the at least one reactor.

10. The system according to claim 8, wherein the hydrogenation unit is arranged in an integrated manner at least one of in the at least one reactor, in a storage container for the hydrogen carrier medium, in a tank container for the hydrogen carrier medium, in a tank vehicle for the hydrogen carrier medium and in an interface for providing hydrogen carrier medium.

11. The system according to claim 8, wherein the at least one reactor is a primary hydrogenation reactor for hydrogenating the hydrogen carrier medium.

12. The system according to claim 8, wherein the at least one reactor is a primary dehydrogenation reactor for dehydrogenating the hydrogen carrier medium.

13. The system according to claim 11, further comprising: a closed loop arrangement including at least one primary hydrogenation reactor and at least one primary dehydrogenation reactor.

14. The system according to claim 9, further comprising a pressure regulation unit for depressurizing the mixture from the reactor.

15. The system according to claim 9, further comprising a heat exchanger for cooling the mixture from the reactor.

16. The method according to claim 3, wherein the mixture from the reactor is depressurized in a pressure regulation unit.

17. The method according to claim 5, wherein the mixture from the reactor is cooled in a heat exchanger.

18. The method according to claim 7, wherein the circulation process is global.

19. The system according to claim 9, wherein the hydrogenation unit is connected to the at least one reactor by means of a fluid line.

20. The system according to claim 9, wherein the hydrogenation unit is directly connected to the at least one reactor by means of a fluid line.

21. The system according to claim 11, wherein hydrogenating the hydrogen carrier medium is performed with supplied hydrogen gas.

22. The system according to claim 12, wherein dehydrogenating the hydrogen carrier medium is performed while releasing hydrogen gas.

23. The system according to claim 13, wherein one hydrogenation unit each is arranged along the flow direction of the mixture downstream of the at least one primary hydrogenation reactor and the at least one primary dehydrogenation reactor.

24. The system according to claim 13, wherein the at least one primary hydrogenation reactor with the downstream hydrogenation unit is arranged at a first location and the at least one primary dehydrogenation reactor with the downstream hydrogenation unit is arranged at a second location.

25. The system according to claim 24, wherein the first location and the second location are arranged at a distance from one another.

26. The system according to claim 24, wherein the first location and the second location are fluidically connected to one another.

27. The system according to claim 14, wherein the hydrogenation unit is arranged upstream of the pressure regulation unit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0071] FIG. 1 shows a schematic illustration of a system according to the invention for the use of hydrogen as a resource with a primary hydrogenation reactor,

[0072] FIG. 2 shows an illustration corresponding to FIG. 1 of a system according to a second embodiment example in which the hydrogenation unit is integrated in the primary hydrogenation reactor,

[0073] FIG. 3 shows an illustration corresponding to FIG. 1 of a system according to a third embodiment example having a primary dehydrogenation reactor,

[0074] FIG. 4 shows an illustration corresponding to FIG. 1 of a system according to a fourth embodiment example, in which various positions of the hydrogenation unit are shown,

[0075] FIG. 5 shows an illustration of a relative hydrogenation capacity related to hydrogen that is dissolved in the hydrogen carrier medium as a function of the relative amount of catalyst in the hydrogenation unit related to the amount of catalyst material in a primary hydrogenation reactor,

[0076] FIG. 6 shows an illustration of systems corresponding to FIG. 1 according to a fifth embodiment example in the form of a, in particular global, closed loop arrangement with a primary hydrogenation reactor, a primary dehydrogenation reactor and two hydrogenation units,

[0077] FIG. 7 shows a diagram to illustrate the dependence of a reactor pressure in a primary dehydrogenation reactor on time,

[0078] FIG. 8 shows a diagram to illustrate an equilibrium position between hydrogenation and dehydrogenation reaction as a function of a reactor pressure and a reactor temperature.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0079] A system marked as a whole with 1 in FIG. 1 comprises a reactor 2 which, according to the embodiment example shown, is designed as a primary hydrogenation reactor. A primary hydrogenation catalyst 3 is arranged in the primary hydrogenation reactor 2, which hydrogenation catalyst 3 serves to carry out a catalytic hydrogenation reaction. A hydrogen supply line 4 for supplying hydrogen gas H.sub.2 and a hydrogen carrier medium supply line 5 for supplying hydrogen carrier medium are connected to the primary hydrogenation reactor 2. The hydrogen carrier medium is in particular a liquid organic hydrogen carrier, which is in particular at least partially discharged (LOHC), which is at least partially charged with hydrogen gas in the primary hydrogenation reactor:

LOHC+H.sub.2.fwdarw.LOHC+

[0080] The at least partially charged hydrogen carrier medium (LOHC+) has a degree of hydrogenation of at least 50%, in particular at least 60%, in particular at least 70%, in particular at least 80%, in particular at least 90%, in particular at least 95%, in particular at least 97% and in particular at most 99%. A hydrogenation degree of 100% means that the hydrogen carrier medium is completely charged with hydrogen gas. This theoretically complete charging does not occur in reality. If the degree of hydrogenation is less than 100%, hydrogen charging of the hydrogen carrier medium is possible. A degree of hydrogenation of 0% means that the hydrogen carrier medium is completely discharged, i.e. in particular no hydrogen is chemically bound to the hydrogen carrier medium.

[0081] A hydrogenation unit 7 is connected to the primary hydrogenation reactor 2 via a fluid line 6.

[0082] The hydrogenation unit 7 is directly connected to the primary hydrogenation reactor 2 by means of the fluid line 6. The hydrogenation unit 7 is arranged downstream of the fluid line 6 of the primary hydrogenation reactor 2. The hydrogenation unit 7 is designed as a separate unit. The hydrogenation unit 7 is arranged outside the primary hydrogenation reactor 2. A hydrogenation catalyst 8 is arranged in the hydrogenation unit 7. In particular, the hydrogenation catalyst 8 is identical to the primary hydrogenation catalyst 3.

[0083] A discharge line 9 is connected to the hydrogenation unit 7 to discharge the at least partially charged hydrogen carrier medium (LOHC+). In particular, the charged hydrogen carrier medium can be stored in a storage container 15 that is provided for this purpose.

[0084] A condenser unit 24 is arranged along the fluid line 6 between the primary hydrogenation reactor 2 and the hydrogenation unit 7. The condenser unit 24 can also be omitted. The condenser unit 24 serves to condense, in particular, vapor-like LOHC components which have been transported from the primary hydrogenation reactor 2 with the released hydrogen gas via the fluid line into the condenser unit 24. The liquefied hydrogen carrier medium with the physically stored hydrogen gas is conveyed further from the condenser unit 24 into the hydrogenation unit 7.

[0085] A separation unit 25 is arranged along the discharge line 9 between the hydrogenation unit 7 and the storage container 15. The separation unit 25 can also be omitted. The separation unit 25 serves to separate residual hydrogen gas upstream of the storage container 15. This prevents or at least minimizes the risk of residual hydrogen gas entering the storage container 15.

[0086] In the following, a method for the use of hydrogen as a resource is explained in more detail. In the primary hydrogenation reactor, the supplied, at least partially discharged hydrogen carrier medium (LOHC) is charged with hydrogen gas (H.sub.2) by means of a catalytic hydrogenation reaction. The hydrogen is chemically bound to the hydrogen carrier medium. The result is a charged hydrogen carrier medium (LOHC+).

[0087] In the liquid charged hydrogen carrier medium (LOHC+), hydrogen gas (H.sub.2) is also physically stored, i.e. provided in a dissolved manner. The proportion of dissolved hydrogen gas in the charged hydrogen carrier medium (LOHC+) is about 0.05 wt. %. The mixture of the liquid charged hydrogen carrier medium (LOHC+) and the dissolved hydrogen gas is fed from the primary hydrogenation reactor 2 to the hydrogenation unit 7 via the fluid line 6. In the hydrogenation unit 7, the dissolved hydrogen is chemically bound to the charged hydrogen carrier medium (LOHC+) by means of a catalytic hydrogenation reaction. This additionally increases the degree of hydrogenation of the charged hydrogen carrier medium (LOHC+) in hydrogenation unit 7.

[0088] In the following, a second embodiment of the invention is described with reference to FIG. 2. Constructively identical parts are given the same reference signs as in the first embodiment example, the description of which is hereby referred to. Constructively different but functionally similar parts are given the same reference signs with a trailing letter a.

[0089] In the system 1a, the hydrogenation unit 7 is arranged in an integrated manner in the primary hydrogenation reactor 2a, in particular in a housing of the primary hydrogenation reactor 2a. A fluid line for connecting the primary hydrogenation reactor 2a with the hydrogenation unit 7 is dispensable.

[0090] In particular, the integrated hydrogenation unit 7 is formed exclusively by the hydrogenation catalyst 8 which is arranged in the primary hydrogenation reactor 2a. In particular, the integrated hydrogenation unit 7 does not have an independent housing. In particular, the hydrogenation catalyst 8 is completely covered by the hydrogen carrier medium. Contact of the hydrogenation catalyst 8 with the hydrogen gas phase is in particular excluded.

[0091] For example, the hydrogenation catalyst 8 is immobilized on an underside of the primary hydrogenation reactor 2a, i.e. in the sump of the primary hydrogenation reactor 2a. This means that in particular outgoing fluid lines are axially secured with a corresponding grid along the longitudinal axis of the container of the primary hydrogenation reactor 2a.

[0092] If the primary hydrogenation reactor 2a is designed as a trickle bed reactor, a lower part of the hydrogenation catalyst 8 can be flooded with hydrogen carrier medium in vertically arranged reaction tubes so that contact with the hydrogen gas phase is excluded.

[0093] It is advantageous if no contact between gaseous hydrogen and hydrogen carrier medium occurs downstream. This prevents hydrogen gas from physically dissolving again in the hydrogen carrier medium.

[0094] The method for the use of the hydrogen as a resource in the system 1a, in particular the post-hydrogenation of the hydrogen carrier medium LOHC+ with the dissolved hydrogen in the hydrogenation unit 7 corresponds to the method according to the first embodiment example, to which reference is hereby made.

[0095] In the following, a third embodiment example of the invention is described with reference to FIG. 3. Constructively identical parts are given the same reference signs as in the first two embodiment examples, the description of which is hereby referred to. Constructively different but functionally similar parts are given the same reference signs with a trailing letter b.

[0096] In the system 1b, the reactor is designed as a primary dehydrogenation reactor 10. The hydrogen carrier medium line 5 for supplying at least partially charged hydrogen carrier medium LOHC+ is connected to the primary dehydrogenation reactor 10. A dehydrogenation catalyst 11 is arranged in the primary dehydrogenation reactor 10 for carrying out the catalytic dehydrogenation reaction. The dehydrogenation catalyst 11 has a catalyst material which comprises in particular platinum, palladium, nickel, rhodium and/or ruthenium. The catalyst material is in particular arranged on a catalyst carrier and in particular attached thereto. The catalyst carrier is in particular aluminum oxide, silicon oxide, silicon carbide and/or activated carbon.

[0097] The hydrogen gas H.sub.2 that is released from the charged hydrogen carrier medium LOHC+ as a result of the catalytic dehydrogenation reaction can be discharged from the primary dehydrogenation reactor 10 via a hydrogen discharge line 12. Alternatively, the released hydrogen gas H.sub.2 can be discharged together with the discharged hydrogen carrier medium LOHC from the primary dehydrogenation reactor 10 via the hydrogen discharge line 12, wherein the initially vaporous hydrogen carrier medium LOHC can be fed to the hydrogenation unit 7 after condensation via a connection line not shown in FIG. 3.

[0098] It is also possible to discharge the discharged hydrogen carrier medium LOHC together with the released hydrogen gas H.sub.2 from the primary dehydrogenation reactor 10 via the fluid line 6. The discharged hydrogen carrier medium LOHC is present in particular in vapor form and can be cooled and/or separated together with the released hydrogen gas H.sub.2 in the condenser unit 24, which forms a cooling/separation unit, in particular by condensation of the LOHC vapor.

[0099] The hydrogenation unit 7 is connected to the primary dehydrogenation reactor 10 via the fluid line 6, in particular directly. It is also possible to arrange further components along the fluid line 6 between the primary dehydrogenation reactor 10 and the hydrogenation unit 7, such as condensation stages and/or recuperation stages. In this case, the primary dehydrogenation reactor 10 is indirectly connected to the hydrogenation unit 7.

[0100] In the primary dehydrogenation reactor 10, the at least partially charged hydrogen carrier medium LOHC+ is dehydrogenated by a catalytic dehydrogenation reaction:

LOHC+.fwdarw.LOHC+H.sub.2

[0101] The released hydrogen gas H.sub.2 is discharged from the primary dehydrogenation reactor 10 via the hydrogen discharge line 12. The at least partially discharged hydrogen carrier medium (LOHC), which is present at least partially in vapor form as a result of the dehydrogenation reaction, is fed to the hydrogenation unit 7 together with the dissolved hydrogen gas via the fluid line 6. In the hydrogenation unit 7, the at least partially dehydrogenated hydrogen carrier medium (LOHC) is charged in a catalytic hydrogenation reaction by chemically binding the dissolved hydrogen to the hydrogen carrier medium. In the hydrogenation unit 7, cooling and a resulting condensation of the vaporous LOHC can take place. Additionally or alternatively, this cooling and condensation can also take place in the condenser unit 24 that is located upstream of the dehydrogenation unit 7.

[0102] Alternatively, it is possible that the hydrogenation unit 7 is arranged in an integrated manner in the primary dehydrogenation reactor 10, as illustrated by the primary hydrogenation reactor in the second embodiment example.

[0103] According to the embodiment example shown, a further hydrogenation unit 7 is arranged, in particular in an integrated manner, in the storage container 15 for the at least partially discharged hydrogen carrier medium (LOHC). Analogous to the integrated hydrogenation unit according to the second embodiment example, the integrated hydrogenation unit 7 is formed exclusively by the hydrogenation catalyst 8, which is arranged in particular in a bottom region of the storage container 15.

[0104] By means of the integrated hydrogenation unit 7, hydrogen that is outgassing and/or has already outgassed from the at least partially discharged hydrogen carrier medium (LOHC) and/or hydrogen that is still physically dissolved under ambient conditions can be chemically bound to the hydrogen carrier LOHC.

[0105] Investigations by the applicant have shown that the pressure in the primary dehydrogenation reactor 10 decreases continuously at a constant temperature at the dehydrogenation catalyst having approximately room temperature, i.e. in a temperature range of approximately 20 C. to 25 C. The pressure decrease occurs in particular over a period of several hours, in particular over several days. In particular, this time interval is at least 20 hours, in particular at least 24 hours, in particular at least 48 hours and in particular at least 60 hours. The pressure decrease leads in particular to the fact that, starting from an overpressure of at least 0.5 barg, the pressure in the reactor decreases until a negative pressure arises amounting to at least 0.2 barg, in particular at least 0.3 barg and in particular 0.4 barg. The dependence of the reactor pressure p.sub.R on the time t is shown schematically in FIG. 7.

[0106] The condenser unit 24 is particularly advantageous in the embodiment example according to FIG. 3. Due to the lower pressure level of the dehydrogenation reaction and due to the reduced partial pressure of the LOHC due to the high hydrogen content, the formation of LOHC vapor is favored. By means of the condenser unit 24, the hydrogen and LOHC vapor can be reliably and efficiently separated from each other.

[0107] In the following, a fourth embodiment example of the invention is described with reference to FIG. 4. Constructively identical parts are given the same reference signs as in the previous embodiment examples, the description of which is hereby referred to. Constructively different but functionally similar parts are given the same reference signs with a trailing letter c.

[0108] The basic structure of the system 1c corresponds to that of the system 1 according to the first embodiment example. In addition, a pressure regulation unit 13 and a heat exchanger 14 are arranged downstream of the hydrogenation unit 7 along the discharge line 9 upstream of the storage container 15 in the system 1c.

[0109] For reasons of illustration, it is not indicated separately in each case in FIG. 4 along the fluid line 6 and along the discharge line 9 that at least partially charged hydrogen carrier medium LOHC+ and physically dissolved hydrogen H.sub.2 are conveyed there. Nevertheless, this is the case, in particular when the hydrogen carrier medium LOHC+ and hydrogen gas have passed one of the hydrogenation units 7, 7, 7, 7 and/or 7, the proportion of physically dissolved hydrogen gas is reduced. The charging of the hydrogen carrier medium LOHC+ is increased.

[0110] By means of the pressure regulation unit 13, the pressure of the mixture is relieved from at least 15 barg, in particular at least 25 barg, in particular at least 30 barg, in particular at Least 40 barg and in particular at least 50 barg to at most 2.0 barg, in particular at most 1.5 barg, in particular at most 1.0 barg and in particular at most 0.5 barg.

[0111] In the heat exchanger 14 that is arranged downstream, the mixture is cooled from a temperature range between 100 C. and 300 C., in particular from 150 C. to 250 C. and in particular from at least 200 C., in particular at least 210 C., in particular at least 220 C., in particular at least 240 C. and in particular at least 260 C. to at most 80 C., in particular at most 70 C., in particular at most 60 C., in particular at most 50 C. and in particular at most 40 C. and then stocked in the storage container 15 for stocking and/or transport.

[0112] In FIG. 4, various positions are shown in dashed lines at which hydrogenation units 7, 7, 7, 7, 7 can be arranged in the system 1c. At each of the positions shown, a hydrogenation unit 7, 7, 7, 7, 7 may be arranged in addition to or as an alternative to the hydrogenation unit 7 shown in system 1c. This means in particular that the hydrogenation unit 7 shown in solid lines in FIG. 4, which is arranged along the fluid line 6 between the primary hydrogenation reactor 2 and the pressure regulation unit 13, can also be omitted.

[0113] It is essential that the respective design of the hydrogenation units 7, 7, 7, 7, 7 is essentially identical and in particular only their position in the system 1c varies. However, it is also conceivable that at least one or more of the hydrogenation units are designed differently, in particular contain different amounts of hydrogenation catalysts and/or different types of hydrogenation catalysts. Accordingly, the reaction conditions, in particular the reaction pressure and/or the reaction temperature for the hydrogenation units can also be different in each case, in particular depending on the position in the system 1c. The positions for the hydrogenation units are explained below.

[0114] The hydrogenation unit 7 is arranged along the fluid flow between the pressure regulation unit 13 and the heat exchanger 14. The arrangement of the hydrogenation unit 7 enables a comparatively efficient hydrogen yield, although the hydrogen yield is reduced compared to the arrangement of the hydrogenation unit 7 upstream of the pressure regulation unit 13.

[0115] The hydrogenation unit 7 is arranged downstream of the heat exchanger 14, in particular between the heat exchanger 14 and the storage container 15. The arrangement of the hydrogenation unit 7 downstream of the heat exchanger 14 prevents outgassing of dissolved hydrogen. This makes it possible to protect measuring instruments that are arranged downstream of the hydrogenation unit 7 from gas bubble formation. Hydrogen gas bubbles that have been released before contacting the hydrogenation catalyst can be dissolved again in the hydrogen carrier medium due to the reduction of the hydrogen gas concentration in the liquid phase of the hydrogen carrier medium by the post-hydrogenation and are thus available for post-hydrogenation.

[0116] A return line 16 branches off from the fluid line 6 and is led back into the primary hydrogenation reactor 2. The hydrogenation unit 7 is arranged along the return line 16 and a pump 17 is arranged downstream thereof in order to return hydrogen carrier medium to the primary hydrogenation reactor 2. The arrangement of the hydrogenation unit 7 along the return line 16 also makes it possible to reduce the formation of gas bubbles and thus protect the pump 17.

[0117] Particularly advantageous in the system 1c is the hydrogenation unit 7 that is arranged upstream of the pressure regulation unit 13. The reaction conditions, in particular pressure and temperature, are particularly advantageous for the desired post-hydrogenation. The post-hydrogenation can be carried out particularly efficiently.

[0118] Calculation results of the applicant are shown in FIG. 5. The diagram shows the functional dependence of the relative hydrogenation capacity as a function of a relative catalyst quantity and as a function of the alternative position of the hydrogenation unit 7, 7, 7. The relative hydrogenation capacity describes the consumption of hydrogen in the hydrogenation unit 7 in relation to the proportion of dissolved hydrogen in the hydrogen carrier medium. A relative hydrogenation capacity of 1.0 exists when the dissolved hydrogen is completely hydrogenated in the hydrogenation unit 7, i.e. is completely chemically bound to the hydrogen carrier medium. The amount of hydrogenation catalyst 8 in hydrogenation unit 7 is given by m.sub.8. The amount of primary hydrogenation catalyst 3 in primary hydrogenation reactor 2 is given by m.sub.3.

[0119] As in the previous embodiment example, the hydrogenation unit 7 is arranged in an integrated manner in the storage container 15. The hydrogenation unit 7 serves to chemically bind outgassing, already outgassed and/or residual physically dissolved hydrogen to the hydrogen carrier medium LOHC+.

[0120] FIG. 5 shows that a high relative hydrogenation capacity and, in particular, a comparatively low use of the hydrogenation catalyst 8 in the primary hydrogenation reactor 2 is possible if the hydrogenation unit 7 is arranged upstream of the pressure regulation unit 13.

[0121] If the hydrogenation unit 7 is arranged downstream of the pressure regulation unit 13, complete hydrogenation is still possible with a relative catalyst quantity of less than 10%.

[0122] As explained above, the arrangement of the hydrogenation unit 7 downstream of the heat exchanger 14 is less relevant with regard to the relative hydrogenation capacity. Even with larger quantities of hydrogenation catalyst 8, only relatively low hydrogenation capacities are possible.

[0123] However, the arrangement of the hydrogenation unit 7 enables an additional safeguard with respect to the logistics and/or transport of the hydrogen carrier medium, since smaller and in particular smallest quantities of hydrogen gas can still be post-hydrogenated. The risk of hydrogen gas outgassing in an uncontrolled and unintended manner is thus additionally reduced.

[0124] A fifth embodiment example of the invention is described below with reference to FIG. 6. Constructively identical parts are given the same reference signs as in the previous embodiment examples. Constructively different but functionally similar parts are given the same reference signs with a trailing letter d.

[0125] For ease of presentation, FIG. 6 does not separately indicate along the fluid lines 6 and/or the discharge lines 9 that physically dissolved hydrogen gas is conveyed together with the hydrogen carrier medium LOHC+, LOHC. Nevertheless, this hydrogen gas is present in physically dissolved form in the hydrogen carrier medium LOHC+, LOHC.

[0126] The system 1d has a primary hydrogenation reactor 2 with a downstream, first hydrogenation unit 7. The system 1d corresponds essentially to the first embodiment example according to FIG. 1, wherein a first interface 18 is arranged at the end of the discharge line 9, which interface 18 serves to provide charged, post-hydrogenated hydrogen carrier medium LOHC+. The first interface 18 serves for dispensing LOHC+ from the first location 19. The first interface 18 can also serve for, in particular temporary, storage of the LOHC+. According to the embodiment example shown, the first interface 18 has an integrated hydrogenation unit 7.

[0127] A second interface 20 is arranged at the beginning of the hydrogen carrier medium supply line 5.

[0128] Via the second interface 20, at least partially discharged hydrogen carrier medium LOHC can be supplied at the first location 19 to the system 1d and, in particular, fed into the primary hydrogenation reactor 2 for hydrogenation. The second interface 20 can serve for at least temporary storage of the at least partially discharged hydrogen carrier medium LOHC. According to the embodiment example shown, an integrated hydrogenation unit 7 is arranged in the second interface 20.

[0129] The system 1d is arranged at a first location 19. The first location 19 is located in particular where there is an energy surplus and in particular where hydrogen gas is to be added to hydrogen carrier medium.

[0130] Furthermore, a second system 1d is arranged, which has a primary dehydrogenation reactor 10 and a downstream, second hydrogenation unit 7. The second hydrogenation unit 7 corresponds essentially to the second hydrogenation unit 7 according to FIG. 4 and is arranged in particular downstream of a heat exchanger not shown in FIG. 6. The second system according to 1d corresponds essentially to the system 1b according to the third embodiment example. The second system 1d is arranged at a second location 21. The second location 21 is arranged remotely from the first location 19. A spatial distance between the locations 19, 21 can be in particular several 100 meters, in particular several kilometers and in particular more than 100 or more than 1,000 kilometers. The second location 21 is arranged in particular where there is a demand for energy. For this purpose, hydrogen gas 2 can be released from the charged hydrogen carrier medium LOHC+ in the primary dehydrogenation reactor 10 and made available via the hydrogen discharge line 12.

[0131] The system 1d has a first interface 18 for providing discharged, post-hydrogenated hydrogen carrier medium LOHC for delivery from the second location 21. Furthermore, the second system 1d comprises a second interface 20, via which at least partially charged hydrogen carrier medium LOHC+, in particular from the first location 19, can be supplied to the second system 1d and fed to the primary dehydrogenation reactor 10 via the hydrogen carrier medium supply line 5. The first interface 18 and the second interface 20 at the second location 21 are substantially identical in design with respect to the first interface 18 and the second interface 20 at the first location 19. In particular, one hydrogenation unit 7 each is arranged in an integrated manner in the first interface 18 and in the second interface 20.

[0132] It is particularly advantageous that the systems 1d and 1d are designed in a global closed loop arrangement and are connected to each other accordingly. In particular, the first interface 18 of the first system 1d is fluidically connected to the second interface 20 of the second system 1d.

[0133] The fluidic connection is symbolized in FIG. 6 by a dashed arrow 22. A fluidic connection 22 is, for example, a pipeline network which can be regional, supraregional, national and/or international. However, a fluidic connection 22 is also formed by transport vehicles such as tank trucks 23, trains and/or ships.

[0134] Accordingly, the first interface 18 of the second system 1d is fluidically connected to the second interface 20 of the first system 1d.

[0135] In particular, due to the closed loop arrangement of the systems 1d, 1d, the efficiency of the hydrogen yield is improved, in particular increased.

[0136] In the following, the influence of reaction pressure and reaction temperature on the chemical equilibrium between hydrogenation reaction and dehydrogenation reaction is explained with reference to FIG. 8. FIG. 8 shows a degree of hydrogenation h of 20%, which exemplarily corresponds to the degree of hydrogenation after dehydrogenation in a primary dehydrogenation reactor. The degree of hydrogenation after dehydrogenation can also be greater or less than 20%. The graphs shown in FIG. 8 correspond to different reaction pressures of 1 bar, 2 bar, 3 bar and 5 bar. The chart shows that, depending on the reaction pressure, temperatures between approximately 280 C. to 310 C. must be undershot for the equilibrium to be above the reduced degree of hydrogenation of 20% of the dehydrogenated hydrogen carrier medium, thereby enabling post-hydrogenation. In particular, it is shown that the higher the reaction pressure, the higher the maximum temperature to be undercut, i.e. approximately 310 C. at 5 bar, approximately 290 C. at 3 bar, approximately 285 C. at 2 bar and approximately 280 C. at 1 bar.