LIQUID HYDROGEN STORAGE

Abstract

A liquid hydrogen store including a cryostatic container for holding the liquid hydrogen, a discharge line for discharge of gaseous hydrogen, a boil-off management system, a boil-off valve in the discharge line for selective opening and closing of a fluidic connection of the discharge line to the boil-off management system, a heat transport line, and one or more thermal contact members to establish thermal contact of the heat transport line with the boil-off management system.

Claims

1. A liquid hydrogen store, comprising: a cryostatic container for holding the liquid hydrogen; a discharge line for discharge of gaseous hydrogen; a boil-off management system that includes a mixing chamber for mixing the gaseous hydrogen with ambient air, a catalytic converter arranged downstream of the mixing chamber for catalytic conversion of the gaseous hydrogen with the ambient air, and an exhaust line arranged downstream of the catalytic converter for discharge of a gas stream to the ambient environment; a boil-off valve in the discharge line for selective opening and closing of a fluidic connection of the discharge line to the boil-off management system; a heat transport line; and one or more thermal contact members to establish thermal contact of the heat transport line with the catalytic converter, and/or an enclosure of the catalytic converter, and/or the exhaust line, the mixing chamber, and/or the discharge line, and/or the boil-off valve.

2. The liquid hydrogen store of claim 1, wherein the heat transport line is formed by a solid-body heat bridge.

3. The liquid hydrogen store of claim 2, wherein the heat transport line is formed by a heat pipe through which a working medium flows.

4. The liquid hydrogen store of claim 1, wherein: the liquid hydrogen store comprises a cover, and the discharge line comprises an internal section which extends within the cover and an external section which extends outside the cover, the one or more thermal contact members establish in thermal contact of the heat transport line with the internal section and the external section.

5. The liquid hydrogen store of claim 4, further comprising fittings at the discharge line which are covered by the cover.

6. The liquid hydrogen store of claim 4, wherein the one or more thermal contact members at the external section is configured for a greater transfer of heat than the one or more thermal contact members at the mixing chamber.

7. The liquid hydrogen store of claim 4, wherein the one or more thermal contact members at the external section of the discharge line is configured for a greater transfer of heat than the one or more thermal contact members at the internal section of the discharge line.

8. The liquid hydrogen store of claim 1, wherein the ambient air is fed into the mixing chamber via the Venturi principle.

9. The liquid hydrogen store of claim 1, further comprising an air feed line to facilitate a flow of the ambient air to the mixing chamber via the Venturi principle.

10. The liquid hydrogen store of claim 9, wherein the one or more thermal contact members are configured to establish thermal contact of the heat transport line with the air feed line.

11. A liquid hydrogen store, comprising: a cryostatic container for holding the liquid hydrogen; a discharge line for discharge of gaseous hydrogen; a boil-off management system that includes a mixing chamber for mixing the gaseous hydrogen with ambient air, a catalytic converter arranged downstream of the mixing chamber for catalytic conversion of the gaseous hydrogen with the ambient air, and an exhaust line arranged downstream of the catalytic converter for discharge of a gas stream to the ambient environment; a boil-off valve in the discharge line for selective opening and closing of a fluidic connection of the discharge line to the boil-off management system; a heat transport line; and one or more thermal contact members to establish thermal contact of the heat transport line with the boil-off management system.

12. The liquid hydrogen store of claim 11, wherein the liquid hydrogen store comprises a cover.

13. The liquid hydrogen store of claim 12, wherein the discharge line comprises an internal section which extends within the cover and an external section which extends outside the cover.

14. The liquid hydrogen store of claim 13, wherein the one or more thermal contact members are to establish thermal contact of the heat transport line with the internal section and the external section.

15. The liquid hydrogen store of claim 14, wherein the one or more thermal contact members at the external section is configured for a greater transfer of heat than the one or more thermal contact members at the mixing chamber.

16. The liquid hydrogen store of claim 14, wherein the one or more thermal contact members at the external section is configured for a greater transfer of heat than the one or more thermal contact members at the internal section.

17. The liquid hydrogen store of claim 11, wherein the ambient air is fed into the mixing chamber via the Venturi principle.

18. The liquid hydrogen store of claim 11, further comprising an air feed line to facilitate a flow of the ambient air to the mixing chamber via the Venturi principle.

19. The liquid hydrogen store of claim 18, wherein the one or more thermal contact members are configured to establish thermal contact of the heat transport line with the air feed line.

20. A liquid hydrogen store, comprising: a cryostatic container for holding the liquid hydrogen; a discharge line for discharge of gaseous hydrogen; a boil-off management system that includes a mixing chamber for mixing the gaseous hydrogen with ambient air, a catalytic converter for catalytic conversion of the gaseous hydrogen with the ambient air, and an exhaust line for discharge of a gas stream to the ambient environment; a boil-off valve in the discharge line for selective opening and closing of a fluidic connection of the discharge line to the boil-off management system; a heat transport line; and one or more thermal contact members to establish thermal contact of the heat transport line with the boil-off management system.

Description

DRAWINGS

[0027] Embodiments will be illustrated by way of example in the drawings and explained in the description hereinbelow.

[0028] FIG. 1 illustrates a schematic illustration of a liquid hydrogen store in accordance with one or more embodiments.

DESCRIPTION

[0029] FIG. 1 illustrates a liquid hydrogen store in accordance with one or more embodiments. The liquid hydrogen store comprises a cryostatic container 1 for holding the liquid hydrogen. The hydrogen H2 is in liquid form in the lower region of the cryostatic container 1 and is in gas form in the upper region of the container 1. A discharge line 2, 4 is configured for discharge of gaseous hydrogen from the upper region of the cryogenic container 1 and runs sectionally through a region of the liquid hydrogen store that has a vacuum 22 and through a region of the liquid hydrogen store that has air 23, in particular ambient air, to the outside.

[0030] In the region of the liquid hydrogen store that has air 23, the liquid hydrogen store comprises fittings 17 at the discharge line 2. The liquid hydrogen store comprises a cover 13. The fittings 17 are covered by the cover 13. The discharge line 2, 4 comprises an internal section 2, which runs within the cover 13 of the liquid hydrogen store, and an external section 4, which runs outside the cover 13.

[0031] The liquid hydrogen store furthermore comprises a boil-off valve 3 in the discharge line 2 for selective opening and closing of a fluidic connection of the discharge line 2, 4 to a boil-off management system, wherein the boil-off management system comprises a nozzle for discharge of the hydrogen, wherein, downstream of the nozzle, the boil-off management system comprises a mixing chamber 5 for mixing of the gaseous hydrogen with air, in particular ambient air, wherein, downstream of the mixing chamber 5, the boil-off management system comprises a catalytic converter 6 for catalytic conversion of the gaseous hydrogen with the air, in particular ambient air, wherein, downstream of the catalytic converter 6, the boil-off management system comprises an exhaust line 7 for discharge of the gas stream to the surroundings. The gas stream is discharged into the surroundings through an exhaust-gas outlet 25 via the exhaust line 7.

[0032] The selective opening and closing of the fluidic connection by the boil-off valve 3 may be realized for example in a pressure-controlled and/or pressure-regulated manner.

[0033] An air feed line 15 allows ambient air to be received through an air inlet 24 to the mixing chamber 5. The feeding of the air into the mixing chamber 5 is realized via the Venturi principle, by way of suction action of the media flowing past, and is thus realized passively, without electrical components.

[0034] In accordance with one or more embodiments, the liquid hydrogen store comprises a heat transport line 11, which is formed by a solid-body heat bridge, and/or is formed by a heat pipe through which a working medium flows. The heat transport line 11 extends from the internal section 2 of the discharge line 2, 4 as far as the exhaust line 7. The heat transport line 11 could, according to requirement, also be designed to be significantly shorter and also extend only as far as the catalytic converter 6 or only as far as the enclosure of the catalytic converter 6 (not illustrated).

[0035] One or more thermal contact members 12 of the heat transport line 11 is configured in each case with respect to the catalytic converter 6 and/or with respect to the enclosure of the catalytic converter 6 and with respect to the exhaust line 7, that is to say in warm regions where heat is transferred to the heat transport line 11, and, at the other side, with respect to the mixing chamber 5 and/or with respect to the air feed 15, with respect to the external discharge line 4 and with respect to the internal discharge line 2, where heat is released in each case. The direction of the flow of heat Q (arrow) is illustrated in the figure and is in the direction counter to the direction of the outflowing hydrogen H2 (further arrows) or in the direction from warm parts to cold parts of the liquid hydrogen store or of the BMS.

[0036] The one or more thermal contact members 9 at the external section 4 of the discharge line 2, 4 is configured here for example for a greater transfer of heat than the one or more thermal contact members 10 of the heat transport line 11 with respect to the mixing chamber 5.

[0037] The one or more thermal contact members 9 at the external section 4 of the discharge line 2, 4 is also configured here for example for a greater transfer of heat than the one or more thermal contact members 8 of the heat transport line 11 with respect to the internal section 2 of the discharge line 2, 4.

[0038] In accordance with one or more embodiments, it is consequently the case that waste heat from the catalytic converter of the boil-off management system (BMS) of a vehicle operated with liquid hydrogen is fed via solid-body heat conduction and/or heat pipes to the cold regions of the BMS, in particular the H2 feed lines 2, 4 and the mixing chamber 5 and/or the air feed line 15, in order to heat these and thereby avoid ice formation, air liquefaction and an excessively high density of the hydrogen gas upstream of the nozzle.

[0039] The surface of the catalytic converter 6 and/or the enclosure of the catalytic converter and of the exhaust pipe 7 of the boil-off management system (BMS) is suitably contacted thermally 12, and a part of the waste heat is transported to the cold regions of the BMS via a solid-body heat bridge or a heat-pipe arrangement 11 with a suitable working medium, or multiple different suitable working media. In said cold regions, the heat is fed to the critical components via suitable one or more thermal contact members 8, 9, 10. Said critical components are:

[0040] Firstly: the mixing chamber 5, where, by way of one or more thermal contact members 10 of the surfaces of chamber and air feed line 15, heat is fed thereto and in this way the icing thereof in the case of outside temperatures just above the freezing point of water is to be prevented, but at the same time, through suitable design, excessive heating in the case of high outside temperatures is prevented.

[0041] Secondly: the external line for boil-off hydrogen 4, where relatively constant cryogenic temperatures prevail in the line and external icing of the line and air liquefaction are most critical. At the same time, an excessively high temperature and consequently an excessively low density of the hydrogen gas upstream of the nozzle is to be avoided here, in order to be able to process all the boil-off gas generated. Conversely, a possible greater input of heat, owing to the position of the line, is less problematic here, it therefore being possible for the one or more thermal contact members 9 to be configured for great feeding of heat and also a constant temperature gradient.

[0042] Thirdly: the internal line for boil-off hydrogen 2: Constant cryogenic temperatures (up to at least approximately 30 K) likewise prevail here. Here, icing is less critical, since, due to the cover of the fittings 13, a certain shielding or a certain insulation effect with respect to the surroundings occurs. An excessively great input of heat, particularly also into the surroundings of the one or more thermal contact members 8, must not take place here, since otherwise sensitive components could be damaged.

[0043] The terms “coupled,” “attached,” or “connected” may be used herein to refer to any type of relationship, direct or indirect, between the components in question, and may apply to electrical, mechanical, fluid, optical, electromagnetic, electromechanical or other connections. In addition, the terms “first,” “second,” etc. are used herein only to facilitate discussion, and carry no particular temporal or chronological significance unless otherwise indicated.

[0044] Those skilled in the art will appreciate from the foregoing description that the broad techniques of the embodiments can be implemented in a variety of forms. Therefore, while the embodiments have been described in connection with particular examples thereof, the true scope of the embodiments should not be so limited since other modifications will become apparent to the skilled practitioner upon a study of the drawings, specification, and following claims.

LIST OF REFERENCE SYMBOLS

[0045] 1 Cryostatic container

[0046] 2 Discharge line, internal section

[0047] 3 Boil-off valve

[0048] 4 Discharge line, external section

[0049] 5 Mixing chamber

[0050] 6 Catalytic converter

[0051] 7 Exhaust line

[0052] 8, 9, 10, 12 Thermal contact members

[0053] 11 Heat transport line

[0054] 13 Cover

[0055] 15 Air feed line

[0056] 17 Fittings

[0057] 22 Vacuum

[0058] 23 Air

[0059] 24 Air inlet

[0060] 25 Exhaust-gas outlet

[0061] H2 Hydrogen

[0062] Q Flow of heat