LIQUID HYDROGEN STORAGE TANK

Abstract

A liquid hydrogen reservoir and a method for operating a liquid hydrogen reservoir. The liquid hydrogen reservoir includes a cryostatic container operable to hold liquid hydrogen; a discharge line operable to discharge gaseous hydrogen in the cryostatic container; a boil-off management system (BMS), a return line, and a boil-off valve (BOV). The BMS that includes a mixing chamber operable to mix the gaseous hydrogen with ambient air, a catalyst arranged downstream of the mixing chamber and operable for a catalytic conversion of the gaseous hydrogen with the ambient air, and an exhaust gas line arranged downstream of the catalyst and operable to discharge the gas stream to the environment. The return line is operable to connect the exhaust gas line to the mixing chamber to facilitate a return flow of at least a partial stream of the exhaust gas line into the mixing chamber. The BOV is arranged in the discharge line and operable to selectively open and close a flow connection of the discharge line to the BMS.

Claims

1. A liquid hydrogen reservoir, comprising: a cryostatic container operable to hold liquid hydrogen; a discharge line operable to discharge gaseous hydrogen in the cryostatic container; a boil-off management system that includes: a mixing chamber operable to mix the gaseous hydrogen with ambient air, a catalyst arranged downstream of the mixing chamber and operable for a catalytic conversion of the gaseous hydrogen with the ambient air, and an exhaust gas line arranged downstream of the catalyst and operable to discharge the gas stream to the environment, a return line operable to connect the exhaust gas line to the mixing chamber to facilitate a return flow of at least a partial stream of the exhaust gas line into the mixing chamber; and a boil-off valve, arranged in the discharge line, and operable to selectively open and close a flow connection of the discharge line to the boil-off management system.

2. The liquid hydrogen reservoir of claim 1, further comprising a temperature-controlled valve arranged in the return line and operable to open and close the return line in response to a detected temperature value.

3. The liquid hydrogen reservoir of claim 2, wherein the detected temperature value is at an air supply line upstream of the mixing chamber.

4. The liquid hydrogen reservoir of claim 2, wherein the detected temperature value is in the mixing chamber.

5. The liquid hydrogen reservoir of claim 1, wherein the return line fluidically is operable to fluidically connect the exhaust gas line to an air supply line arranged upstream of the mixing chamber, to facilitate the return flow of the partial stream of the exhaust gas line into the mixing chamber through the air supply line.

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

7. The liquid hydrogen reservoir of claim 1, wherein the partial stream of the exhaust gas line is fed into the mixing chamber via the Venturi principle.

8. The liquid hydrogen reservoir of claim 1, wherein: the ambient air is fed into the mixing chamber via the Venturi principle, and the partial stream of the exhaust gas line is fed into the mixing chamber via the Venturi principle.

9. The liquid hydrogen reservoir of claim 1, further comprising a branch line to fluidically connect the return line to the exhaust gas line.

10. A method for operating a liquid hydrogen reservoir according to claim 1, the method comprising: providing a liquid hydrogen reservoir that includes: a cryostatic container operable to hold liquid hydrogen, a discharge line operable to discharge gaseous hydrogen in the cryostatic container; a boil-off management system that includes: a mixing chamber operable to mix the gaseous hydrogen with ambient air, a catalyst arranged downstream of the mixing chamber and operable for a catalytic conversion of the gaseous hydrogen with the ambient air, and an exhaust gas line arranged downstream of the catalyst and operable to discharge the gas stream to the environment, a return line operable to connect the exhaust gas line to the mixing chamber to facilitate a return flow of at least a partial stream of the exhaust gas line into the mixing chamber; and a boil-off valve, arranged in the discharge line, and operable to selectively open and close a flow connection of the discharge line to the boil-off management system; facilitating a return flow of at least a partial stream of the exhaust gas line into the mixing chamber by opening the return line when a detected temperature value in the boil-off management system is less than a predefined temperature value.

11. The method of claim 10, further comprising preventing the return flow of at least a partial stream of the exhaust gas line into the mixing chamber by closing the return line when the detected temperature value in the boil-off management system is greater than the predefined temperature value.

12. A liquid hydrogen reservoir, comprising: a cryostatic container operable to hold liquid hydrogen; a discharge line operable to discharge gaseous hydrogen in the cryostatic container; a boil-off management system that includes: a mixing chamber operable to mix the gaseous hydrogen with ambient air, an exhaust gas line arranged downstream of the mixing chamber and operable to discharge the gas stream to the environment, a return line operable to connect the exhaust gas line to the mixing chamber to facilitate a return flow of at least a partial stream of the exhaust gas line into the mixing chamber; a boil-off valve, arranged in the discharge line for selectively opening and closing a flow connection of the discharge line to the boil-off management system; a temperature sensor operable to detect a temperature value in the boil-off management system; and a temperature-controlled valve arranged in the return line and operable to open and close the return line in response to the detected temperature value.

13. The liquid hydrogen reservoir of claim 12, wherein the boil-off management system further includes a catalyst arranged downstream of the mixing chamber and operable for a catalytic conversion of the gaseous hydrogen with the ambient air.

14. The liquid hydrogen reservoir of claim 12, wherein the detected temperature value is at an air supply line upstream of the mixing chamber.

15. The liquid hydrogen reservoir of claim 12, wherein the detected temperature value is in the mixing chamber.

16. The liquid hydrogen reservoir of claim 12, wherein the return line fluidically is operable to fluidically connect the exhaust gas line to an air supply line arranged upstream of the mixing chamber, to facilitate the return flow of the partial stream of the exhaust gas line into the mixing chamber through the air supply line.

17. The liquid hydrogen reservoir of claim 12, wherein the ambient air is fed into the mixing chamber via the Venturi principle.

18. The liquid hydrogen reservoir of claim 12, wherein the partial stream of the exhaust gas line is fed into the mixing chamber via the Venturi principle.

19. The liquid hydrogen reservoir of claim 12, wherein: the ambient air is fed into the mixing chamber via the Venturi principle, and the partial stream of the exhaust gas line is fed into the mixing chamber via the Venturi principle.

20. The liquid hydrogen reservoir of claim 12, further comprising a branch line to fluidically connect the return line to the exhaust gas line.

Description

DRAWING

[0023] One or more embodiments will be illustrated by way of example in the drawings and explained in the description hereinbelow.

[0024] FIG. 1 illustrates a schematic illustration of a liquid hydrogen reservoir, in accordance with one or more embodiments.

DESCRIPTION

[0025] FIG. 1 illustrates, in accordance with one or more embodiments, a liquid hydrogen reservoir and thus, an arrangement for warming the air fed to the boil-off system of a cryostatic container 1. The liquid hydrogen reservoir comprises a cryostatic container 1 operable to hold liquid hydrogen (H.sub.2). The hydrogen is in liquid form in the lower region of the cryostatic container 1 and is gaseous in the upper region of the container 1. A discharge line 2 is operable to discharge gaseous hydrogen from the upper region of the cryogenic container 1 and extends to the outside in some portions through a region of the liquid hydrogen reservoir that is under vacuum 22 and through a region of the liquid hydrogen reservoir that contains air 23.

[0026] The liquid hydrogen reservoir further comprises a boil-off valve (BOV) 3 in the discharge line 2 for selectively, preferably automatically under the control/regulation of overpressure, opening and closing a flow connection of the discharge line 2 to a BMS. In order to protect the tank, the BOV 3 is usually controlled in response to the pressure in the tank.

[0027] The BMS comprises a mixing chamber 5 for mixing the gaseous hydrogen with air, a catalyst 6 arranged downstream of the mixing chamber 5 for the catalytic conversion of the gaseous hydrogen with the air, and an exhaust gas line 7 arranged downstream of the catalyst 6 for discharging the gas stream to the environment.

[0028] In accordance with one or more embodiments, a return line 20 fluidically connects the exhaust gas line 7 to the mixing chamber 5, so that a partial stream of the exhaust gas line 7 can be fed back into the mixing chamber 5. The return line 20 is fluidically connected to the exhaust gas line 7 via a branch line 21.

[0029] A temperature-controlled valve 8 is arranged in the return line 20, and operable to open and close the return line 20 in response to a detected or measured temperature value. The temperature-controlled valve 8 is operatively connected to a temperature probe/sensor 10, and is operable to open and close in response to a detected temperature value by the temperature probe/sensor 10 at an air supply line 9 arranged upstream of the mixing chamber 5 and/or in the mixing chamber 5. The return line 20 fluidically connects the exhaust gas line 7 to the air supply line 9 upstream of the mixing chamber 5, so that a partial stream of the exhaust gas line 7 can be fed back into the mixing chamber 5 through the air supply line 9. The other partial stream of the exhaust gas line 7 is discharged into the environment through an exhaust gas outlet 25.

[0030] The air supply line 9 allows surrounding ambient air to be taken in through an air inlet 24. The ambient air is fed into the mixing chamber 5 and the partial stream of the exhaust gas line 7 is fed into the air supply line 9 and further into the mixing chamber 5 via the Venturi principle by the suction action of the media flowing past in each case, and thus, takes place passively, without electrical components. Thus, via the Venturi principle, a (small) portion of the exhaust gas of the BMS is fed back into the mixing chamber 5 via the air inlet 24 by lateral suction at the air supply line 9. The exhaust gas is branched off in such a manner that the exhaust gas stream is impeded as little as possible (even with the valve closed) and moreover, at the inlet into the branching return line 20, where possible the total hydrodynamic pressure of the exhaust gas is present at the exhaust gas line 7. The temperature-controlled valve 8 blocks the gas stream as soon as the detected temperature value at the air inlet 24 or in the mixing chamber 5 is greater than or otherwise exceed a predefined threshold value.

[0031] A portion of the warm exhaust gas of the BMS of a vehicle powered by liquid hydrogen can therefore, at ambient temperatures close to 0° C., be fed back into the mixing chamber 5 of the BMS via Venturi suction, in order to warm the mixing chamber internally and thus, avoid the formation of ice.

LIST OF REFERENCE SYMBOLS

[0032] 1 cryostatic container [0033] 2 discharge line [0034] 3 boil-off valve (BOV) [0035] 5 mixing chamber [0036] 6 catalyst [0037] 7 exhaust gas line [0038] 8 temperature-controlled valve [0039] 9 air supply line [0040] 10 temperature probe/sensor [0041] 20 return line [0042] 21 branch line [0043] 22 vacuum [0044] 23 air [0045] 24 air inlet [0046] 25 exhaust gas outlet [0047] H2 hydrogen