A hydrogen gas storage arrangement with two inlets in the reservoir and a method of controlling such an arrangement

Abstract

A hydrogen storage arrangement, comprising an enclosure (1) defining a hydrogen gas storage chamber (2), said enclosure (1) comprising a first inlet (3) and a second inlet (4) located remote from the first inlet (3), and a hydrogen gas circuit (5) for conducting hydrogen gas from a hydrogen gas source (6) to the gas storage chamber (2) and for conducting hydrogen gas from the gas storage chamber (2) to a hydrogen gas recipient device (16), said hydrogen gas circuit (5) comprising a valve arrangement (7) for controlling a flow of hydrogen gas in the circuit (5). The hydrogen gas circuit (5) is configured to enable the hydrogen gas source (6) to deliver hydrogen gas into the hydrogen gas storage chamber (2) through each of the first inlet (3) and the second inlet (4), and / or to enable the hydrogen gas recipient device (16) to receive hydrogen gas from the gas storage chamber (2) through each of the first inlet and second inlet (4).

Description

[0001] A HYDROGEN GAS STORAGE ARRANGEMENT WITH TWO INLETS IN THE RESERVOIR AND A METHOD OF CONTROLLING SUCH AN ARRANGEMENT

[0002] TECHNICAL FIELD

[0003] The present invention relates to a hydrogen storage arrangement, comprising an enclosure defining a hydrogen gas storage chamber, said enclosure comprising a first inlet and a second inlet located remote from the first inlet, and a hydrogen gas circuit for conducting hydrogen gas from a hydrogen gas source to the gas storage chamber and for conducting hydrogen gas from the gas storage chamber to a hydrogen gas recipient device, said hydrogen gas circuit comprising a valve arrangement for controlling a flow of hydrogen gas in the circuit.

[0004] Typically, but not necessarily, the hydrogen gas recipient comprises a direct reduction shaft of a device for production of sponge iron from iron ore by means of reduction with hydrogen gas.

[0005] The present invention also relates to a method of controlling the operation of a hydrogen storage arrangement according to the invention.

[0006] BACKGROUND

[0007] During introducing of hydrogen gas into a gas storage chamber, the gas temperature in the chamber increases due to compression, limiting the storage capacity and / or fill rate against the maximum operation temperature. During evacuation the stored gas cools by expansion, which again may limit the evacuation rate against the low operation temperature limit.

[0008] During introduction of gas the gas storage chamber wall in the region of the gas inlet gets heated. During evacuation of the gas from the gas storage chamber, the gas storage chamber wall in the region of the gas outlet will get cooled. Walls comprising layers such as bitumen layers and a drain arrangement comprising tubes or hole arrangements in which a cooling medium is provided, are sensitive to excessive cooling or heating.

[0009] One way of preventing excessive heating during introducing is to decrease the fill rate. Another way may comprise precooling of the hydrogen gas before introducing.

[0010] One way of preventing excessive cooling during evacuation is to decrease the evacuation rate. Another way would be to preheat the gas chamber wall before or in connection to the evacuation of gas.

[0011] Such prior art solutions either require specific gas heating or cooling arrangements or will negatively affect the possibilities of fast introducing or evacuation.

[0012] THE OBJECT OF THE INVENTION

[0013] It is an object of the present invention to provide a hydrogen storage arrangement which enables fast introducing and evacuation of hydrogen gas to and from a gas storage chamber without excessive heating or cooling of the wall structure of the gas storage chamber.

[0014] SUMMARY

[0015] The object of the invention is achieved by means of a hydrogen storage arrangement, comprising

[0016] - an enclosure defining a hydrogen gas storage chamber, - - a hydrogen gas circuit for conducting hydrogen gas from a hydrogen gas source to the gas storage chamber and for conducting hydrogen gas from the gas storage chamber to a hydrogen gas recipient device, said hydrogen gas circuit comprising - a valve arrangement for controlling a flow of hydrogen gas in the circuit, characterised in that the hydrogen gas circuit is configured to enable the hydrogen gas source to deliver hydrogen gas into the hydrogen gas storage chamber through each of a first inlet and a second inlet,

[0017] and / or to enable the hydrogen gas recipient device to receive hydrogen gas from the gas storage chamber through each of the first inlet and second inlet.

[0018] The first inlet and / or the second inlet may be defined by an opening in the enclosure. They may also be defined by the end of a tube extending through the enclosure wall and into the hydrogen gas storage chamber. Such a tube may extend through an opening in the enclosure wall and extend a substantial distance into the chamber, and in some embodiments the tube extends all the way to the region of the enclosure wall opposite to said opening. The term “inlet” is, of course, not limiting in the sense that it cannot work in practice also as an outlet, once the flow direction of the gas through that inlet is reversed. Reversing the flow direction of the gas through the first and / or in connection to gas introduction and gas evacuation is a characterising feature of the present invention.

[0019] By allowing multiple injection / withdrawal locations in the operation and change of inlet for the introducing and evacuation respectively, thermal energy may be stored in the wall structure of the enclosure, where it is needed in the upcoming operation phases, delaying the formation of local hot / cold spots. Thermal layering may also be reduced by deliberate choosing, and change, of the inlet via which gas is introduced into or evacuated from the hydrogen gas storage chamber.

[0020] According to some embodiments, the hydrogen gas circuit is configured to enable the hydrogen gas source to deliver hydrogen gas into the hydrogen gas storage chamber through each of the first inlet and the second inlet. In other words, the hydrogen gas circuit is configured to enable gas introduction into the gas storage chamber through each of the first inlet and the second inlet.

[0021] According to some embodiments, the hydrogen gas circuit is configured to enable the hydrogen gas recipient device to receive hydrogen gas from the gas storage chamber through each of the first inlet and second inlet. In other words, the hydrogen gas circuit is configured to enable evacuation from the gas storage chamber through each of the first inlet and the second inlet. According to some embodiments, the hydrogen storage arrangement comprises a diffusor provided in the gas storage chamber in a region of at least one of the first inlet and the second inlet, wherein said diffusor is configured to direct gas flowing into the gas storage chamber through that inlet towards the neighbouring wall of the enclosure. The term “neighbouring” may be referred to as a part of the wall adjacent or close to the diffusor.

[0022] According to some embodiments, the hydrogen storage arrangement comprises a first diffusor provided in the gas storage chamber in a region of the first inlet, wherein said diffusor is configured to direct gas flowing into the gas storage chamber through said first inlet towards the neighbouring wall of the enclosure.

[0023] According to some embodiments, the hydrogen storage arrangement comprises a second diffusor provided in the gas storage chamber in a region of the second inlet, wherein said second diffusor is configured to direct gas flowing into the gas storage chamber through the second inlet towards the neighbouring wall of the enclosure.

[0024] According to some embodiments, the hydrogen storage arrangement comprises a tempering arrangement for local active tempering of the wall of the enclosure in the region of at least one of the first inlet and the second inlet.

[0025] According to some embodiments, the tempering arrangement comprises a cooling arrangement for local active cooling of the wall of the enclosure in the region of the first inlet.

[0026] According to some embodiments, the tempering arrangement comprises a heating arrangement for local active heating of the wall of the enclosure in the region of the second inlet.

[0027] According to some embodiments, the wall of the enclosure comprises a steel liner, a bitumen layer, a reinforced concrete layer, a drain arrangement and a surrounding rock structure. According to some embodiments, the enclosure comprises an upper wall portion and a lower wall portion, wherein the first inlet is provided in the upper wall portion, and the second inlet is provided in the lower wall portion.

[0028] According to some embodiments, the hydrogen storage arrangement comprises a third inlet provided between the first inlet and the second inlet, wherein the hydrogen gas circuit is configured to introduce and / or remove gas to / from the gas storage chamber through the third inlet. Preferably, the third inlet is located approximately halfway between the first inlet and the second inlet.

[0029] According to some embodiments, the hydrogen gas circuit is configured to enable the hydrogen gas source to deliver hydrogen gas into the hydrogen gas storage chamber through the third inlet and / or to enable the hydrogen gas recipient device to receive hydrogen gas from the gas storage chamber through the third inlet. According to some embodiments, the hydrogen gas circuit is configured to enable the hydrogen gas source to deliver hydrogen gas into the hydrogen gas storage chamber through the third inlet and to enable the hydrogen gas recipient device to receive hydrogen gas from the gas storage chamber through the third inlet.

[0030] During fast charge / discharge the most extreme temperatures are experienced at the centre of the gas storage chamber, furthest away from the walls. A third gas inlet in this middle location far from the walls where the pV-cooling / heating effect is useful to remove hot gas or extract cold gas, while the top / bottom port is used for delivery of cooled or heated recirculated gas. In a less extreme operational profile the thermal layering and convection within the gas storage chamber may on the other hand be dominating, leading to the most extreme temperatures being formed at the high / low points in the gas storage chamber. Also here a third input allows to supply / withdraw the gas to / from its optimal location. Furthermore, a third inlet allows to concentrate an active recirculation heating / cooling to the correct section of the vessel. The object of the invention is also achieved by means of a method of controlling the operation of a hydrogen storage arrangement according to the invention, characterised in that it comprises the steps of:

[0031] - introducing or evacuating hydrogen gas into / from the gas storage chamber through one of the first inlet and the second inlet, and

[0032] - changing said introducing or evacuating to the other of the first inlet and second inlet. In other words, the invention suggests reversal of the flow direction of gas that is either introduced into the gas storage chamber or evacuated from the gas storage chamber through a predetermined inlet / outlet.

[0033] According to some embodiments, the method comprises the steps of:

[0034] - measuring the amount of hydrogen gas in the gas storage chamber,

[0035] - predicting an amount of hydrogen gas that is to be introduced into the gas storage chamber or to be evacuated from the gas storage chamber during a predetermined time period and

[0036] - changing said introducing or evacuating to the other of the first inlet and second inlet on basis of the predicted amount to be introduced or evacuated and on basis of the temperature obtained in the wall of the enclosure in the region of the respective first inlet and second inlet. Alternatively, the invention comprises changing said introducing or evacuating to the other of the first inlet and second inlet on basis of the predicted amount to be introduced or evacuated and on basis of the gas temperature obtained in the region of the respective first inlet and second inlet during said introduction or evacuation.

[0037] A predicted temperature change in the wall of the enclosure that would be the result of the predicted introduction / evacuation amount and introduction / evacuation rate, for a given the temperature of the hydrogen gas to be introduced, will thus be calculated. The change of introducing inlet and / or evacuating inlet, i.e. the reversal of gas flow direction, will thus be determined on basis on the predicted temperature change in order to prevent excessive heating / cooling of the wall of the enclosure in the region of the respective first and second inlet. The change of introducing inlet and / or evacuating inlet, i.e. the reversal of gas flow direction, may also be based only on the temperature of the gas in gas storage chamber and for the purpose of preventing unwanted gas temperature differences in the gas storage chamber (hot spots, cold spots).

[0038] According to some embodiments, the hydrogen storage arrangement comprises a tempering arrangement for local active tempering of the wall of the enclosure in the region of at least one of the first inlet and the second inlet, wherein, on basis of the predicted amount of gas to be introduced / evacuated into / from the storage chamber, the tempering arrangement is activated in order to prevent excessive heating / cooling of the wall in the region of the inlet through which gas is introduced / evacuated.

[0039] According to some embodiments, the method comprises the steps of:

[0040] - measuring or estimating the temperature of the wall in the region of at least one of the first inlet and the second inlet, and

[0041] - changing an introduction through one of the first inlet and second inlets to an introduction through the other of the first inlet and second inlet if the measured or estimated temperature of the wall in the region of said one of the first inlet and second inlet is above a predetermined temperature.

[0042] According to some embodiments, the method comprises the steps of:

[0043] - measuring or estimating the temperature of the wall in the region of at least one of the first inlet and the second inlet, and

[0044] - changing an evacuation through one of the first inlet and second inlets to an introduction through the other of the first inlet and second inlets if the measured or estimated temperature of the wall in the region of said one of the first inlet and second inlet is below a predetermined temperature.

[0045] According to some embodiments, the method comprises the steps of:

[0046] - measuring or estimating the temperature of hydrogen gas in the hydrogen gas storage chamber in the region of at least one of the first inlet and the second inlet, and

[0047] - changing an introduction through one of the first inlet and second inlet to an introduction through the other of the first inlet and second inlet if the measured or estimated temperature of the hydrogen gas in said region of said one of the first inlet and second inlet is above a predetermined temperature.

[0048] According to some embodiments, the method comprises the steps of:

[0049] - measuring or estimating the temperature of the temperature of hydrogen gas in the hydrogen gas storage chamber in a region of at least one of the first inlet and the second inlet, and

[0050] - changing an evacuation through one of the first inlet and second inlet to an introduction through the other of the first inlet and second inlet if the measured or estimated temperature of the hydrogen gas in said region of said one of the first inlet and second inlet is below a predetermined temperature.

[0051] According to some embodiments, the hydrogen gas recipient device comprises a reduction shaft of a device for production of sponge iron from iron ore by means of reduction with hydrogen gas.

[0052] According to some embodiments, the hydrogen gas recipient device comprises the gas storage chamber. In such a case, simultaneous introducing and evacuating of the gas storage chamber is a circulating motion of the hydrogen gas, which may also be used for affecting temperature conditions in the enclosure and of the gas itself. According to some embodiments, there is provided a tempering device in the hydrogen gas circuit, and, when the hydrogen gas recipient device comprises the gas storage chamber, and there is a recirculation of the hydrogen gas, the tempering device is used for affecting the temperature of the gas, and thus the temperature conditions in the gas storage chamber.

[0053] BRIEF DESCRIPTION OF THE DRAWINGS

[0054] An embodiment of the invention will now be described with reference to the annexed drawing, on which:

[0055] Fig. 1 is a schematic representation of an embodiment of a hydrogen storage arrangement according to the invention, Fig. 2 shows an alternative embodiment of a hydrogen storage arrangement according to the invention,

[0056] Fig. 3 shows a further embodiment of a hydrogen storage arrangement according to the invention, and

[0057] Fig. 4 shows an embodiment of a hydrogen storage arrangement comprising a third inlet.

[0058] DETAILED DESCRIPTION

[0059] Fig. 1 shows a hydrogen storage arrangement, which comprises an enclosure 1 defining a hydrogen gas storage chamber 2. The enclosure 1 comprises a first inlet 3 and a second inlet 4 located remote from the first inlet 3.

[0060] The hydrogen storage arrangement further comprises a hydrogen gas circuit 5 for conducting hydrogen gas from a hydrogen gas source 6 to the gas storage chamber 2 and for conducting hydrogen gas from the gas storage chamber 2 to a hydrogen gas recipient device 16. The hydrogen gas source 6 is an electrolyser arrangement. The hydrogen gas recipient device 16 comprises a reduction shaft of a device for production of sponge iron from iron ore by means of reduction with hydrogen gas. The gas recipient device may also comprise the gas storage chamber 2 itself, whereby, the gas flow is a recirculation gas flow.

[0061] The hydrogen gas circuit 5 further comprises a valve arrangement 7 for controlling direction of hydrogen gas flow in the circuit 5. The hydrogen gas circuit 5 is configured to enable the hydrogen gas source 6 to deliver hydrogen gas into the hydrogen gas storage chamber 2 through each of the first inlet 3 and the second inlet 4 and to enable the hydrogen gas recipient device 16 to receive hydrogen gas from the hydrogen gas storage chamber 2 through each of the first inlet and second inlet 4. The hydrogen gas circuit 5 is configured to enable simultaneous introduction and evacuation of the hydrogen gas storage chamber 2 through the first inlet 3 and the second inlet 4. The hydrogen gas circuit 5 further comprises a compressor for compressing the hydrogen gas that is to be conducted from the hydrogen gas source 6 to the hydrogen gas storage chamber 2, and a pressure reducing device 17 for reducing the pressure of the gas that is to be conducted from the hydrogen gas storage chamber 2 to the hydrogen gas recipient 16.

[0062] There is also provided a first diffusor 8 in the gas storage chamber 2 in a region of the first inlet 3, wherein said first diffusor 8 is configured to direct gas flowing into the gas storage chamber 2 through said first inlet 3 towards the neighbouring wall 9 of the enclosure 1. A second diffusor 13 is provided in the gas storage chamber 2 in a region of the second inlet 4, wherein said second diffusor 13 is configured to direct gas flowing into the gas storage chamber 2 through the second inlet 4 towards the neighbouring wall 9 of the enclosure 1.

[0063] A tempering arrangement 10, 14 is provided for local active tempering of the wall 9 of the enclosure 1 in the region of at least one of the first inlet 3 and the second inlet 4. The tempering arrangement comprises a cooling arrangement 10 for local active cooling of the wall 9 of the enclosure 1 in the region of the first inlet 3. The cooling arrangement 10 may comprise tubing provided in the wall 9 and means (not shown) for conducting a cooling fluid through said tubing. The tempering arrangement also comprises a heating arrangement 14 for local active heating of the wall 9 of the enclosure 1 in the region of the second inlet 4. The heating arrangement 14 may be an electrical heating arrangement provided in the wall 9 of the enclosure 1.

[0064] The wall 9 of the enclosure 1 comprises a steel liner, a bitumen layer and a drain arrangement and a surrounding rock structure. It also comprises a reinforced concrete layer.

[0065] The enclosure 1 comprises an upper wall portion 11 and a lower wall portion 12, and the first inlet 3 is provided in the upper wall portion 11 and the second inlet 4 is provided in the lower wall portion 12.

[0066] The invention also comprises a method of controlling the operation of the hydrogen storage arrangement disclosed hereinabove. The method comprises the steps of: - introducing or evacuating hydrogen gas into / from the gas storage chamber 2 through one of the first inlet 3 and the second inlet 4, and

[0067] - changing said introducing or evacuating to the other of the first inlet 3 and second inlet 4 provided that a predetermined condition is fulfilled.

[0068] The method further includes the steps of

[0069] - measuring the amount of hydrogen gas in the gas storage chamber 2 .

[0070] - predicting an amount of hydrogen gas that is to be introduced into the gas storage chamber 2 or to be evacuated from the gas storage chamber 2 during a predetermined time period and

[0071] - changing said introduction or evacuation to the other of the first inlet 3 and second inlet 4 on basis of the predicted amount to be introduced or evacuated and on basis of the temperature obtained in the wall 9 of the enclosure 1 in the region of the respective first inlet 3 and second inlet 4.

[0072] The method also comprises the step of, activating the tempering arrangement 10, 14 in order to prevent excessive heating / cooling of the wall 9 in the region of the inlet 3, 4 through which gas is introduced / evacuated. This may be done on basis of the predicted amount of gas to be introduced / evacuated into / from the storage chamber 2, and on basis of the temperature of the wall 9 in the region of the first inlet 3 and the second inlet 4.

[0073] Accordingly, method comprises the steps of:

[0074] - measuring the temperature of the wall 9 in the region of at least one of the first inlet 3 and the second inlet 4, and

[0075] - changing an introduction through one of the first inlet 3 and second inlet 4 to an introduction through the other of the first inlet 3 and second inlet 4 if the measured temperature of the wall 9 in the region of said one of the first inlet 3 and second inlet 4 is above a predetermined temperature.

[0076] It also comprises the steps of:

[0077] - measuring the temperature of the wall 9 in the region of at least one of the first inlet 3 and the second inlet 4, and - changing an evacuation through one of the first inlet 3 and second inlet 4 to an introduction through the other of the first inlet 3 and second inlet 4 if the measured temperature of the wall 9 in the region of said one of the first inlet 3 and second inlet 4 is below a predetermined temperature.

[0078] According to an alternative embodiment, the method comprises the steps of:

[0079] - measuring or estimating the temperature of hydrogen gas in the hydrogen gas storage chamber in the region of at least one of the first inlet 3 and the second inlet 4, and

[0080] - changing an introduction through one of the first inlet and second inlet 4 to an introduction through the other of the first inlet 3 and second inlet 4 if the measured or estimated temperature of the hydrogen gas in said region of said one of the first inlet 3 and second inlet 4 is above a predetermined temperature.

[0081] According to an alternative embodiment, the method comprises the steps of:

[0082] - measuring or estimating the temperature of the temperature of hydrogen gas in the hydrogen gas storage chamber in a region of at least one of the first inlet 3 and the second inlet 4, and

[0083] - changing an evacuation through one of the first inlet 3 and second inlet 4 to an introduction through the other of the first inlet 3 and second inlet 4 if the measured or estimated temperature of the hydrogen gas in said region of said one of the first inlet 3 and second inlet 4 is below a predetermined temperature.

[0084] According to one embodiment, the hydrogen gas recipient device 16 comprises the gas storage chamber 2. This is a temporary condition. During this temporary condition, gas is circulated through the hydrogen gas storage chamber 2 while being introduced through one of the first inlet 3 and the second inlet 4 and evacuated through the other of the first inlet 3 and the second inlet 4. In order to avoid the upcoming of hot spots and cold spots. The temperature of the gas may be measured or estimated in the region of the respective first and second inlet, and the flow direction of the gas may be reversed in accordance with the teaching disclosed hereinabove, i.e. when the wall temperature or gas temperature in the region of at least one of the first inlet 3 and the second inlet 4 goes above or below a predetermined value.

[0085] Fig. 2 is an embodiment of a part of the schematic hydrogen storage arrangement shown in fig. A first tube 18, which is a part of the gas circuit 5, extends to an opening in an upper wall of the enclosure 1 and defines the first inlet 3 in the region of said upper wall.

[0086] A second tube 19, which is coaxial with and extends inside the first tube 18, extends Into the gas storage chamber 2 through the first inlet 3. The second tube 19 extends to the region of a bottom wall of the enclosure 1 and defines the second inlet 4 in said region of the bottom wall.

[0087] Fig. 3 is an embodiment which differs from the one shown in fig. 2 in that there is provided tempering tubing 20 which is coaxial with the first tube 18 and the second tube 19 along a part of the extension of the first tube 18 and the second tube 19 and which encloses the second tube 19. The tempering tubing 18 is filled with a tempering fluid, preferably a liquid, and will enable tempering (heating or cooling), of the gas in the first tube 18 and the gas in the second tube 19. A tempering fluid source is 21 is also provided. The tempering fluid may consist of water. The enclosure is provided in rock and at a predetermined distance from a ground level, and the first tube 18, the second tube 19 and the tempering tubing 20 extends from the enclosure 1 towards the ground level. The provision of the second tube 19 and the tempering tubing 20 inside the first tube 18 preferably extends a substantial part of said distance, preferably a major part of said distance.

[0088] Fig. 4 shows a further embodiment of a hydrogen storage arrangement, comprising a third inlet 22 provided between the first inlet 3 and the second inlet 4 as seen in the height direction of the arrangement. The hydrogen gas circuit is configured to introduce and remove gas to / from the gas storage chamber 2 through the third inlet 22. The hydrogen gas circuit 5 (not shown in fig. 4) is configured to enable the hydrogen gas source 6 (not shown in fig. 4) to deliver hydrogen gas into the hydrogen gas storage chamber 2 through the third inlet 22 and to enable the hydrogen gas recipient device to receive hydrogen gas from the gas storage chamber 2 through the third inlet 22.

[0089] During fast charge / discharge the most extreme temperatures are experienced at the centre of the gas storage chamber, furthest away from the walls. According to one embodiment, the third gas inlet 22 is used to remove hot gas or extract cold gas, while one of the first inlet 3 and the second inlet 4 is used for introduction of cooled or heated gas. According to one embodiment, the third inlet 22 is used for either introduction or removal of gas into the gas storage chamber, while the gas is circulated to / from the gas storage chamber 2 through one of the first inlet 3 and the second inlet 4.

Claims

CLAIMS1. A hydrogen storage arrangement, comprising- an enclosure (1) defining a hydrogen gas storage chamber (2),- a hydrogen gas circuit (5) for conducting hydrogen gas from a hydrogen gas source (6) to the gas storage chamber (2) and for conducting hydrogen gas from the gas storage chamber (2) to a hydrogen gas recipient device (16), said hydrogen gas circuit (5) comprising- a valve arrangement (7) for controlling a flow of hydrogen gas in the circuit (5), characterised in that the hydrogen gas circuit (5) is configured to enable the hydrogen gas source (6) to deliver hydrogen gas into the hydrogen gas storage chamber (2) through each of a first inlet (3) and a second inlet (4),and / orto enable the hydrogen gas recipient device (16) to receive hydrogen gas from the gas storage chamber (2) through each of the first inlet and second inlet (4).

2. A hydrogen storage arrangement according to claim 1 , wherein the hydrogen gas circuit (5) is configured to enable the hydrogen gas source (6) to deliver hydrogen gas into the hydrogen gas storage chamber (2) through each of the first inlet (3) and the second inlet (4).

3. A hydrogen storage arrangement according to claim 1 or 2, wherein the hydrogen gas circuit (5) is configured to enable the hydrogen gas recipient device (16) to receive hydrogen gas from the gas storage chamber (2) through each of the first inlet (3) and second inlet (4).

4. A hydrogen storage arrangement according to any one of claims 1-3, comprising a diffusor (8) provided in the gas storage chamber (2) in a region of at least one of the first inlet (3) and second inlet (4), wherein said diffusor (8) is configured to direct gas flowing into the gas storage chamber (2) through that inlet towards the neighbouring wall (9) of the enclosure (1).

5. A hydrogen storage arrangement according to any of claims 1 -4, comprising a first diffusor (8) provided in the gas storage chamber (2) in a region of the first inlet (3), wherein said diffusor is configured to direct gas flowing into the gas storage chamber (2) through said first inlet (3) towards the neighbouring wall (9) of the enclosure (1 ),6. A hydrogen storage arrangement according to any one of claims 1-5, comprising a second diffusor (8) provided in the gas storage chamber (2) in a region of the second inlet (4), wherein said second diffusor (8) is configured to direct gas flowing into the gas storage chamber (2) through the second inlet (4) towards the neighbouring wall (9) of the enclosure (1).

7. A hydrogen storage arrangement according to any one of claims 1-6, comprising a tempering arrangement (10) for local active tempering of the wall (9) of the enclosure (1 ) in the region of at least one of the first inlet (3) and the second inlet (4).

8. A hydrogen storage arrangement, according to claim 7, wherein the tempering arrangement (10) comprises a cooling arrangement for local active cooling of the wall (9) of the enclosure (1 ) in the region of the first inlet (3).

9. A hydrogen storage arrangement according to any one of claims 7 or 8, wherein the tempering arrangement (10) comprises a heating arrangement for local active heating of the wall (9) of the enclosure (1 ) in the region of the second inlet (4).

10. A hydrogen storage arrangement according to any one of claims 1 -9, wherein the wall (9) of the enclosure (1) comprises a steel liner, a bitumen layer, a reinforced concrete layer, a drain arrangement and a surrounding rock structure.

11. A hydrogen storage arrangement according to any one of claims 1 -10, wherein the enclosure (1 ) comprises an upper wall portion (11 ) and a lower wallportion (12), and wherein the first inlet (3) is provided in the upper wall portion (11) and the second inlet (4) is provided in the lower wall portion (12).

12. A hydrogen storage arrangement according to claim 11 , comprising a third inlet provided between the first inlet (3) and the second inlet (4), wherein the hydrogen gas circuit is configured to introduce and / or remove gas to / from the gas storage chamber through the third inlet.

13. A hydrogen storage arrangement according to claim 11 or 12, comprising a third inlet provided between the first inlet (3) and the second inlet (4), wherein the hydrogen gas circuit (5) is configured to enable the hydrogen gas source (6) to deliver hydrogen gas into the hydrogen gas storage chamber (2) through the third inlet and / or to enable the hydrogen gas recipient device (16) to receive hydrogen gas from the gas storage chamber (2) through the third inlet.

14. A method of controlling the operation of a hydrogen storage arrangement comprising- an enclosure (1) defining a hydrogen gas storage chamber (2),- a hydrogen gas circuit (5) for conducting hydrogen gas from a hydrogen gas source (6) to the gas storage chamber (2) and for conducting hydrogen gas from the gas storage chamber (2) to a hydrogen gas recipient device (16), said hydrogen gas circuit (5) comprising- a valve arrangement (7) for controlling a flow of hydrogen gas in the circuit (5), wherein the hydrogen gas circuit (5) is configured to enable the hydrogen gas source (6) to deliver hydrogen gas into the hydrogen gas storage chamber (2) through each of a first inlet (3) and a second inlet (4),and / orto enable the hydrogen gas recipient device (16) to receive hydrogen gas from the gas storage chamber (2) through each of the first inlet and second inlet (4), said method being characterised in that it comprises the steps of:- introducing or evacuating hydrogen gas into / from the gas storage chamber (2) through one of the first inlet (3) and the second inlet (4), and- changing said introducing or evacuating to the other of the first inlet (3) and second inlet (4).

15. A method according to claim 14, comprising the steps of:- measuring the amount of hydrogen gas in the gas storage chamber (2).- predicting an amount of hydrogen gas that is to be introduced into the gas storage chamber (2) or to be evacuated from the gas storage chamber (2) during a predetermined time period and- changing said introducing or evacuating to the other of the first inlet (3) and second inlet (4) on basis of the predicted amount to be introduced or evacuated and on basis of the temperature obtained in the wall (9) of the enclosure (1 ) in the region of the respective first inlet (3) and second inlet (4).

16. A method according to claim 15, wherein the hydrogen storage arrangement comprises a tempering arrangement (10) for local active tempering of the wall (9) of the enclosure (1 ) in the region of at least one of the first inlet (3) and the second inlet (4), and wherein, on basis of the predicted amount of gas to be introduced / evacuated into / from the storage chamber (2), the tempering arrangement (10) is activated in order to prevent excessive heating / cooling of the wall (9) in the region of the inlet (3, 4) through which gas is introduced / evacuated.

17. A method according to any of claims 14-16, comprising the steps of:- measuring or estimating the temperature of the wall (9) in the region of at least one of the first inlet (3) and the second inlet (4), and- changing an introduction through one of the first inlet and second inlet (4) to an introduction through the other of the first inlet (3) and second inlet (4) if the measured or estimated temperature of the wall (9) in the region of said one of the first inlet (3) and second inlet (4) is above a predetermined temperature.

18. A method according to any one of claims 14-17 comprising the steps of - measuring or estimating the temperature of the wall (9) in the region of at least one of the first inlet (3) and the second inlet (4), and- changing an evacuation through one of the first inlet (3) and second inlet (4) to an introduction through the other of the first inlet (3) and second inlet (4) if the measured or estimated temperature of the wall (9) in the region of said one of the first inlet (3) and second inlet (4) is below a predetermined temperature.

19. A method according to any one of claims 14-18, comprising the steps of: - measuring or estimating the temperature of hydrogen gas in the hydrogen gas storage chamber in the region of at least one of the first inlet (3) and the second inlet (4), and- changing an introduction through one of the first inlet and second inlet (4) to an introduction through the other of the first inlet (3) and second inlet (4) if the measured or estimated temperature of the hydrogen gas in said region of said one of the first inlet (3) and second inlet (4) is above a predetermined temperature.

20. A method according to any one of claims 14-15 or 19 comprising the steps of:- measuring or estimating the temperature of the temperature of hydrogen gas in the hydrogen gas storage chamber in a region of at least one of the first inlet (3) and the second inlet (4), and- changing an evacuation through one of the first inlet (3) and second inlet (4) to an introduction through the other of the first inlet (3) and second inlet (4) if the measured or estimated temperature of the hydrogen gas in said region of said one of the first inlet (3) and second inlet (4) is below a predetermined temperature.

21. A method according to any one of claims 14-20, wherein the hydrogen gas recipient device (16) comprises a reduction shaft of a device for production of sponge iron from iron ore by means of reduction with hydrogen gas.

22. A method according to any one of claims 14-21 , wherein the hydrogen gas recipient device (16) comprises the gas storage chamber (2).

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