Storage and transportation of hydrogen

Abstract

The invention relates to a method for transporting hydrogen in a material cycle, the method comprising the following steps: a) providing hydrogen at a first location; b) directly or indirectly reacting the hydrogen with a first boron compound to obtain borazane; c) transporting the borazane to a second location; d) releasing the hydrogen from the borazane to obtain a second boron compound; e) transporting the second boron compound, directly or after further conversion, to the first location.

Description

[0001] Hydrogen storage and transport

[0002] The present invention relates to a method for transporting and storing hydrogen, in particular to make hydrogen manageable for many applications and easily usable for users.

[0003] Hydrogen offers a number of advantages as an energy storage medium, in particular the fact that the only by-product produced during combustion is water.

[0004] The disadvantage is that in gaseous form, the energy per cubic meter is low, so the gas must either be compressed or liquefied. The energy density is approximately 1.4 kWh / m 3 at 700 bar and room temperature or 2.4 kWh / m 3 when liquefied at -253 °C.

[0005] Storage and transport are difficult in both compressed and liquefied forms because of the complex equipment required. In liquefied form, energy is required for cooling, and additional energy is needed during storage to maintain low temperatures.

[0006] It is also known to store hydrogen absorptively by incorporating it into solids, for example in zeolites, or to chemically convert it into other compounds, such as methanol, ammonia, etc. For storage and transport, absorptive storage would in principle be ideal, but the energy densities are particularly low.

[0007] When hydrogen production and consumption are closely spaced, transport in gaseous form at atmospheric pressure via pipeline is preferable. If this is not possible, or if hydrogen storage is required for an extended period, these options are not viable. Therefore, there is still a need for hydrogen transport or storage options that overcome at least some of the disadvantages of the current state of the art.

[0008] The object is achieved by a method for transporting hydrogen in a material cycle comprising the following steps: a) Providing hydrogen at a first location b) Reacting the hydrogen directly or indirectly with a first boron compound to obtain borazane c) Transporting the borazane to a second location d) Releasing the hydrogen from the borazane to obtain a second boron compound e) Transporting the second boron compound directly or after further conversion to the first location.

[0009] According to the invention, hydrogen is provided at a first location. This hydrogen can be produced in a variety of ways, for example, by electrolysis using electrical current. The electricity itself can be generated in any way, but is preferably 'green,' ie, generated, for example, by wind power or solar cells.

[0010] This hydrogen is then reacted with a boron compound at a first location to obtain borazane. Borazane (H3B-NH3) can be obtained in a variety of ways. Such syntheses are generally known to those skilled in the art. In a preferred embodiment, ammonia is first produced from the hydrogen:

[0011] Haber-Bosch process: N2+ 3 H2--> 2 NH3 Borazane can then be obtained, for example, by reaction with diborane (B2H6):

[0012] Borazane synthesis: 2 NH3 + B2H6 --> 2 H3B-NH3

[0013] Other routes for the synthesis of borazane are also possible.

[0014] The first location is preferably a place where renewable energy is readily available, for example from photovoltaics, wind, geothermal energy.

[0015] In a further step, the borazane is transported to a second location. Borazane can be in solid form, which can simplify handling during production, transport, and the final hydrogen release reaction. However, the borazane can also be in aqueous solution. Liquid transport, e.g., via pumps, is advantageous in transport and storage tanks, as well as in continuous and discontinuous reaction apparatus.

[0016] At the second location, hydrogen can then be released from the borazane, resulting in a boron compound as a byproduct. This can be reused for borazane production at the hydrogen production site, in the spirit of a circular economy.

[0017] This second location preferably has more difficult conditions regarding the availability of renewable energy.

[0018] One variant, for example, is the release of hydrogen by heating, whereby hexagonal (BN)x is formed from the borazane and hydrogen is released. In another embodiment, borazane is reacted by adding inorganic or organic acids, and boric acid or borate is formed in addition to hydrogen.

[0019] In a particularly preferred embodiment of the process, the distance between the first and second locations is such that transport of the hydrogen in gaseous form, for example, via a pipeline, is not possible. The distance can be, for example, 100 km or more or 500 km or more. For example, it would be conceivable to produce the hydrogen in sunny countries north or south of the Mediterranean, convert it into borazan, and then use it in northern Europe.

[0020] In some embodiments, it may be useful to store the borazan. Storage can take place at the site of production (the first site), at the site of consumption (the second site), or at a third site, for example, in a borazan storage facility.

[0021] In addition to the release of hydrogen through heating or acid, it can also be released through a catalyst, particularly a heterogeneous catalyst. A typical heterogeneous catalyst is a platinum-based catalyst.

[0022] In one embodiment of the invention, the first and second boron compounds are identical. In one embodiment, the first and second boron compounds are different. In both cases, the boron compound obtained after the release of hydrogen can be further converted before being transported to the first location.

[0023] An example would be the formation of hydrogen from borazane with acids, producing borate. Before transport, the borate could be converted into hexagonal boron nitride, for example, which is then transported back to the original site for further conversion into diborane.

[0024] In principle, transport is also possible in the form of borate.

[0025] In some embodiments of the invention, it is necessary to convert the resulting second boron compound back into the first boron compound.

[0026] A variant would be that the second boron compound obtained is boric acid, which is converted into hexagonal (BN)x with urea or ammonia under a nitrogen atmosphere and then converted back into borazane with AlCl3 / HCl.

[0027] H .

[0028] B(

[0029] + AICIJ / HCI hexag

[0030] Implementation using AICU / HCI

[0031] Diborane can then be the first and second boron compound. Alternatively, a reaction with hydrazine / ammonia can also occur: N2H4 / NH3 hex-BN -> H3B-NH3

[0032] In one embodiment, the synthesis is acidic / catalytic. B(OH)3 is reacted with sodium and HCl to form borazane:

[0033] B(OH)3+ NH3+4 Na + 4 HCl + H2-> H3B-NH3 + 3 H2O + 4 NaCl

[0034] In an alternative form, the conversion can also be carried out thermally:

[0035] 4 BNH + 5 CI2 + 5 NaOH + 15 H2-> 4 H3B-NH3 + 5 NaCl + 5 H2O + 5 HCl

[0036] In a preferred embodiment, the reaction is based on H2O2:

[0037] 4 BNH + 5 H2O2 + 15 H2-> 4 H3B-NH3 + 10 H2O

[0038] The reaction schemes are simplified.

[0039] When hydrogen is released, hydrogen-poor compounds based on BN are formed; these can be chemically reprocessed to produce borazane.

[0040] The special feature of the present invention is that it involves a material cycle in which the boron compound (for example as (BN)x) is transported back from the second to the first location to be converted back into borazane there. This fundamentally distinguishes the process from other chemical bonding processes, for example as methanol, which do not use a material cycle. One aspect of the invention is also the use of borazane as a storage form for hydrogen. Just as gas is prepared today in gas storage facilities, borazane can be used to store reserves of hydrogen that can be consumed when needed. It is therefore preferred that the storage period in this embodiment is at least 30 days or at least 60 days or even longer. This can also be useful when hydrogen is transported as NH3. The storage of large quantities of ammonia (e.g.A storage facility (e.g., in a current natural gas storage facility) would pose a significant safety risk due to the toxicity of ammonia. This would then potentially result in the formation of borazane and the release of hydrogen at the same location. Borazane is also a storage form of ammonia.

[0041] The advantages of borazane over ammonia, metal hydrides and hydrocarbons as a 'hydrogen storage' are in particular:

[0042] - Borazan is not toxic

[0043] - Borazan does not react with water under normal conditions to form explosive gases

[0044] - Borazan is solid and non-volatile

[0045] - Borazan releases hydrogen even at very moderate temperatures starting from about 50 °C

[0046] - Borazan can be easily recycled.

[0047] The invention is further illustrated by the following examples:

[0048] Example 1

[0049] Hydrogen is generated in a region with high solar irradiation in southern Spain using solar power and converted into ammonia with nitrogen. The ammonia is converted into borazan using BH3. The resulting powdered borazan is loaded onto a specially adapted ship and transported to Bremerhaven. There, the borazan is thermally "degassed" (i.e., hydrogen is released), and the released hydrogen is transported to consumers via pipelines.

[0050] The BNH produced as a by-product is transported by ship from Bremerhaven to southern Spain, where this substance is then converted back into borazane using green hydrazine (from ammonia and hydrogen peroxide, synthesized using the anthraquinone process).

[0051] Example 2

[0052] Hydrogen is generated in a region with high solar irradiation in southern Spain using solar power and converted into ammonia with nitrogen. The ammonia is converted into borazan using BH3. The resulting powdered borazan is loaded onto a specially adapted ship and transported to Bremerhaven. There, the borazan is stored underground in powder form or as an aqueous solution. Depending on the demand for hydrogen, the borazan is degassed to release hydrogen.

Claims

Patent claims 1. A method for transporting hydrogen in a material cycle comprising the following steps: a) Providing hydrogen at a first location b) Reacting the hydrogen directly or indirectly with a first boron compound to obtain borazane c) Transporting the borazane to a second location d) Releasing the hydrogen from the borazane to obtain a second boron compound e) Transporting the second boron compound directly or after further conversion to the first location.

2. The process according to claim 1, wherein the indirect reaction comprises converting the hydrogen to ammonia or an ammonium compound which reacts with a boron compound to form boarazane.

3. The method according to claim 1 or 2, wherein the method further comprises - Storing the borazan at the first, second and / or third location.

4. The method according to claim 3, wherein the storage is for at least 30 days.

5. Method according to one of the preceding claims, wherein the distance between the first and the second location is more than 100 km, preferably more than 500 km.

6. A process according to any one of the preceding claims, wherein the borazane is transported as a powder or in solution.

7. A method according to any one of the preceding claims, wherein the first boron compound and the second boron compound are identical.

8. Method according to one of the preceding claims, wherein the first and / or the second boron compound (BN) X is.

9. A method according to any one of the preceding claims, wherein the first and / or the second boron compound is BCh 3 ' includes.

10. Process according to one of the preceding claims, wherein the release in step d) occurs by heating, by acid or by a heterogeneous catalyst.

11. The process of claim 10, wherein the heterogeneous catalyst comprises platinum.

12. A process according to any one of the preceding claims, comprising converting the second boron compound into the first boron compound.

13. A process according to any one of the preceding claims, wherein the borazane is produced via hydrogen peroxide.

14. Use of borazane as a storage form of hydrogen or ammonia.

15. Use according to claim 14, wherein the storage period is at least 30 days.

16. Use according to claim 14 or 15, wherein the borazane is stored as a powder or in solution.

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