Hydrogen storage system

Abstract

To reliably supply hydrogen to a hydrogen utilization device during start-up of the hydrogen utilization device.SOLUTION: A hydrogen storage system 100 comprises: hydrogen storage alloys 11A, 11B that stores hydrogen to be supplied to a hydrogen utilization device C; a heat generation unit 71 having a heat generation agent that generates heat by reacting with water; and heating units 72A, 72B that heat the hydrogen storage alloys 11A, 11B with heat generated by the heat generation unit 71 at start-up.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a hydrogen storage system. [Background technology]

[0002] Patent document 1 discloses a hydrogen storage system comprising a hydrogen storage alloy container in which a hydrogen storage alloy is housed, a heat medium flow path through which a heat medium moves to transfer heat to the hydrogen storage alloy, and a temperature adjustment unit that adjusts the temperature of the heat medium moving in the heat medium flow path. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-35479 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the invention described in Patent Document 1, water (heat medium) in a water tank is heated by a heater, and the hydrogen storage alloy is heated by the heated water, thereby desorbing hydrogen from the hydrogen storage alloy.

[0005] However, in the invention described in Patent Document 1, for example, when starting up a fuel cell (hydrogen utilization device), if a power outage or other condition occurs that makes it impossible to secure a power source to operate the heater, the hydrogen storage alloy cannot be heated. As a result, hydrogen cannot be supplied to the fuel cell, and there is a risk that the fuel cell cannot be started.

[0006] An object of the present invention is to supply hydrogen to a hydrogen utilization device at the start of the hydrogen utilization device without receiving an external power supply. [Means for solving the problem]

[0007] The present invention is a hydrogen storage system comprising a hydrogen storage alloy that absorbs hydrogen to be supplied to a hydrogen utilization device, a heat generating section having a heat generating agent that generates heat by reacting with water, and a heating section that heats the hydrogen storage alloy with heat generated by the heat generating section at start-up. Effect of the Invention

[0008] According to the present invention, hydrogen can be supplied to the hydrogen utilization device at the start of the hydrogen utilization device without receiving power from an external source. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a hydrogen energy system to which a hydrogen storage system according to a first embodiment of the present invention is applied. [Diagram 2] FIG. 2 is a characteristic diagram showing the relationship between the amount of hydrogen stored in the hydrogen storage alloy according to the embodiment of the present invention and the pressure inside the hydrogen storage tank. [Diagram 3] FIG. 3 is a schematic diagram of a hydrogen energy system to which a hydrogen storage system according to a second embodiment of the present invention is applied. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] First Embodiment A hydrogen absorption system 100 according to a first embodiment will be described with reference to FIGS.

[0012] The hydrogen absorption system 100 supplies hydrogen to a generator or driving source that uses hydrogen gas as fuel and is installed or mounted in a building or mobility, and absorbs or releases hydrogen gas generated by a hydrogen generation device P. First, with reference to Fig. 1, a hydrogen energy system S to which the hydrogen absorption system 100 according to an embodiment of the present invention is applied will be briefly described.

[0013] As shown in FIG. 1, the hydrogen energy system S includes a hydrogen absorption system 100, a hydrogen generation device P that supplies hydrogen to the hydrogen absorption system 100, and a hydrogen utilization device C that utilizes the hydrogen released from the hydrogen absorption system 100.

[0014] The hydrogen generation device P generates hydrogen by electrolyzing water. The hydrogen generation device P is equipped with a temperature regulator (not shown) that regulates the temperature of the generated hydrogen, and a pressure regulator (not shown) that regulates the pressure of the generated hydrogen.

[0015] The hydrogen utilization device C is an energy generation source that produces energy through a chemical reaction of hydrogen released from the hydrogen absorption system 100. Specifically, the energy generation source is a fuel cell or a hydrogen engine. A fuel cell produces electric energy by reacting hydrogen released from the hydrogen absorption system 100 with oxygen, and a hydrogen engine produces rotational energy by combusting hydrogen released from the hydrogen absorption system 100. The fuel cell and the hydrogen engine emit heat and water or water vapor.

[0016] The hydrogen absorption system 100 includes hydrogen absorption alloys 11A, 11B for absorbing hydrogen, hydrogen storage tanks 10A, 10B in which the hydrogen storage alloys 11A, 11B are respectively housed, circulation circuits 20A, 20B in which water (fluid) circulates and which exchanges heat with the hydrogen storage alloys 11A, 11B, a cooling mechanism 30 that cools the water flowing through the circulation circuits 20A, 20B, and heating mechanisms 40A, 40B that heat the water flowing through the circulation circuits 20A, 20B.

[0017] The hydrogen storage tanks 10A, 10B are connected to the hydrogen generation device P by flow paths 51A, 51B, respectively, and are connected to the hydrogen utilization device C by flow paths 52A, 52B, respectively. In other words, the hydrogen storage tanks 10A, 10B are provided in parallel in the flow path connecting the hydrogen generation device P and the hydrogen utilization device C.

[0018] The flow paths 51A and 51B are provided with on-off valves 53A and 53B that open or close the flow paths 51A and 51B, and the flow paths 52A and 52B are provided with on-off valves 54A and 54B that open or close the flow paths 52A and 52B. The operations of the on-off valves 53A and 53B and the on-off valves 54A and 54B are controlled by a controller 60.

[0019] Next, the hydrogen storage tanks 10A, 10B, the circulation circuits 20A, 20B, and the heating mechanisms 40A, 40B will be described. Since the hydrogen storage tanks 10A, 10B, the circulation circuits 20A, 20B, and the heating mechanisms 40A, 40B have the same configuration, the following description will focus on the hydrogen storage tank 10A, the circulation circuit 20A, and the heating mechanism 40A, and the hydrogen storage tank 10B, the circulation circuit 20B, and the heating mechanism 40B will be omitted by assigning the same numerals to the configurations of the hydrogen storage tank 10A, the circulation circuit 20A, and the heating mechanism 40B in the drawings that are the same as those of the hydrogen storage tank 10A, the circulation circuit 20A, and the heating mechanism 40A. The configurations of the hydrogen storage tank 10A, the circulation circuit 20A, and the heating mechanism 40A will be distinguished by adding "A" to the reference numerals, and the configurations of the hydrogen storage tank 10B, the circulation circuit 20B, and the heating mechanism 40B will be distinguished by adding "B" to the reference numerals.

[0020] The hydrogen storage tank 10A is composed of a pressure vessel, and a hydrogen storage alloy 11A is accommodated inside the hydrogen storage tank 10A. As the hydrogen storage alloy 11A, AB5 type, AB2 type, A2B type, solid solution type (BCC alloy), etc. can be used.

[0021] A pressure sensor 55A is provided downstream of the on-off valve 53A in the flow path 51A. The pressure sensor 55A detects the pressure around the hydrogen storage alloy 11A (the hydrogen pressure in the hydrogen storage tank 10A). The pressure sensor 55A may be provided upstream of the on-off valve 54A in the flow path 52A.

[0022] In the hydrogen energy system S, hydrogen generated by the hydrogen generation device P is supplied to the hydrogen storage tank 10A through the flow path 51A by opening the on-off valve 53A. Moreover, the supply of hydrogen generated by the hydrogen generation device P to the hydrogen storage tank 10A is cut off by closing the on-off valve 53A.

[0023] Furthermore, in the hydrogen energy system S, by opening the on-off valve 54A, hydrogen in the hydrogen storage tank 10A is supplied to the hydrogen utilization device C through the flow path 52A and the pressure reducing valve 56. By closing the on-off valve 54A, the supply of hydrogen in the hydrogen storage tank 10A to the hydrogen utilization device C is cut off.

[0024] Next, the circulation circuit 20A will be described.

[0025] The circulation circuit 20A circulates water and exchanges heat with the hydrogen storage alloy 11A, thereby adjusting the temperature of the hydrogen storage alloy 11A.

[0026] As shown in FIG. 1, the circulation circuit 20A further includes a pump 21A for circulating water within the circulation circuit 20A, a first heat exchange section 22A that performs heat exchange with the heating mechanism 40A, a second heat exchange section 23A that performs heat exchange with the hydrogen storage alloy 11A, a cooling mechanism 30 that cools the water flowing within the circulation circuit 20A, a bypass flow path 24A that bypasses the cooling mechanism 30, a control valve 25A that controls the distribution of the flow rate to the cooling mechanism 30 and the bypass flow path 24A, a first temperature sensor 26A that detects the water temperature on the inlet side of the second heat exchange section 23A, and a second temperature sensor 27A that detects the water temperature on the outlet side of the second heat exchange section 23A.

[0027] The pump 21A is driven by a motor (not shown). The type of the pump 21A is not particularly limited, but the pump 21A may be a centrifugal pump, a gear pump, a vane pump, or the like.

[0028] The first heat exchange unit 22A exchanges heat with the heating mechanism 40A and receives heat from the heating mechanism 40A to heat the water circulating in the circulation circuit 20A.

[0029] The second heat exchange section 23A exchanges heat with the hydrogen storage alloy 11A to adjust the temperature of the hydrogen storage alloy 11A.

[0030] The control valve 25A distributes the water that has passed through the second heat exchange section 23A to the cooling mechanism 30 and the bypass flow path 24A. Specifically, the control valve 25A is configured as a three-way valve. The control valve 25A is controlled by the controller 60, and controls the flow rate of the water distributed to the cooling mechanism 30 and the bypass flow path 24A. In this embodiment, the control valve 25A is configured as a three-way valve, but the control valve 25A may be configured as two two-way valves.

[0031] The cooling mechanism 30 is composed of a chiller, a cooling tower, a radiator, etc. The cooling mechanism 30 may be any mechanism as long as it has at least a function as a radiator that releases heat of the water circulating in the circulation circuit 20A to the atmosphere.

[0032] In this embodiment, one cooling mechanism 30 cools the water circulating in the circulation circuits 20A and 20B. In other words, in this embodiment, the cooling mechanism 30 is common to the circulation circuits 20A and 20B, but the cooling mechanism 30 may be provided separately in the circulation circuits 20A and 20B.

[0033] The heating mechanism 40A includes a circulation circuit 41A through which water circulates as a heat medium, a pump 42 for circulating the water within the circulation circuit 41A, a third heat exchange unit 43A provided in the circulation circuit 41A and performing heat exchange with the first heat exchange unit 22A, a fourth heat exchange unit 44 provided in the circulation circuit 41A and performing heat exchange with the hydrogen utilization device C, and an on-off valve 45A provided between the pump 42 and the third heat exchange unit 43A in the circulation circuit 41A and for allowing or blocking the flow of water from the pump 42 to the third heat exchange unit 43A.

[0034] The circulation circuit 41A transfers the exhaust heat generated in the hydrogen utilization device C to the circulation circuit 20A by circulating the water therein.

[0035] The pump 42 is driven by a motor (not shown). There is no particular limitation on the type of the pump 42, but the pump 42 may be a centrifugal pump, a gear pump, a vane pump, or the like.

[0036] The third heat exchange section 43A exchanges heat with the first heat exchange section 22A, and heats the water circulating in the circulation circuit 20A with the heat of the water circulating in the circulation circuit 41A.

[0037] The fourth heat exchange section 44 exchanges heat with the hydrogen utilization device C, and heats the water circulating in the circulation circuit 41A with exhaust heat generated when the hydrogen utilization device C is driven.

[0038] In this manner, the heating mechanism 40A utilizes the exhaust heat generated when the hydrogen utilization device C is driven to heat the water circulating within the circulation circuit 41A.

[0039] In this embodiment, one pump 42 circulates the water in the circulation circuits 41A and 41B, and one fourth heat exchange section 44 heats the water circulating in the circulation circuits 41A and 41B. In other words, in this embodiment, the pump 42 and the fourth heat exchange section 44 are common to the circulation circuits 41A and 41B, but the pump 42 and the fourth heat exchange section 44 may be provided individually in the circulation circuits 41A and 41B, respectively.

[0040] Next, the adsorption and desorption of hydrogen in the hydrogen storage alloy 11A will be described with reference to Fig. 2. Fig. 2 is a graph showing the relationship between the pressure, temperature, and amount of hydrogen absorbed in the hydrogen storage alloys 11A and 11B (hydrogen storage tanks 10A and 10B). Note that the solid line in Fig. 2 shows the characteristics during adsorption, and the dotted line shows the characteristics during desorption.

[0041] First, the adsorption of hydrogen into the hydrogen storage alloy 11A will be described. Hydrogen generated by the hydrogen generation device P is guided into the hydrogen storage tank 10A through the flow path 51A by opening the on-off valve 53A. In this embodiment, the pressure of the hydrogen supplied from the hydrogen generation device P is about 0.8 MPa. The hydrogen guided into the hydrogen storage tank 10A is adsorbed by the hydrogen storage alloy 11A. When the hydrogen storage alloy 11A adsorbs hydrogen, the temperature of the hydrogen storage alloy 11A rises due to an exothermic reaction.

[0042] As shown in Fig. 2, the hydrogen storage alloy 11A absorbs less water at the same pressure as the temperature increases. Therefore, in this embodiment, the pump 21A is driven during absorption to circulate the water in the circulation circuit 20A. In this embodiment, the pump 21A is driven so that the discharge flow rate is constant.

[0043] The water discharged from the pump 21A cools the hydrogen storage alloy 11A in the second heat exchanger 23A. The water (which has passed through the second heat exchanger 23A) whose temperature has increased by heat exchange with the hydrogen storage alloy 11A is guided to the cooling mechanism 30 through the control valve 25A. In the cooling mechanism 30, the heat of the water passing through is removed, and the temperature of the water is reduced. The water cooled by the cooling mechanism 30 is guided to the pump 21A and discharged from the pump 21A again. By circulating the water in the circulation circuit 20A in this way, the heat generated by the hydrogen storage alloy 11A can be released to the outside. During adsorption, the pump 42 of the heating mechanism 40A is stopped or the opening / closing valve 45A is closed, so that heat exchange is not performed in the first heat exchanger 22A. As a result, the water in the circulation circuit 20A is not heated.

[0044] In this embodiment, when hydrogen is adsorbed by the hydrogen storage alloy 11A, the hydrogen pressure is controlled to be constant at about 0.8 MPa. Specifically, when the hydrogen pressure detected by the pressure sensor 55A decreases, the controller 60 controls the control valve 25A to guide a portion of the water that has passed through the second heat exchanger 23A to the bypass flow path 24A. As a result, the water guided to the bypass flow path 24A is discharged again from the pump 21A without passing through the cooling mechanism 30, i.e., without being cooled.

[0045] If the hydrogen storage alloy 11A is cooled too strongly, that is, if the temperature of the water passing through the second heat exchanger 23A is too low, the temperature of the hydrogen drops, and as a result, the hydrogen pressure drops. Therefore, a part of the water that has passed through the second heat exchanger 23A is led to the bypass flow passage 24A to bypass the cooling mechanism 30, thereby increasing the temperature of the water led to the second heat exchanger 23A. In this way, when the hydrogen pressure drops, the hydrogen pressure can be maintained at a constant pressure by suppressing the cooling of the hydrogen storage alloy 11A. Note that, for this control, the relationship between the hydrogen pressure and the opening degree of the control valve 25A (the amount of flow rate distributed to the cooling mechanism 30 and the bypass flow passage 24A) is obtained in advance by experiments or the like, and these relationships are stored in the controller 60, and the control is performed based on the stored relationship. Feedback control may also be performed based on the pressure detected by the pressure sensor 55A. Alternatively, control may be performed using the first temperature sensor 26A and the second temperature sensor 27A provided in the circulation circuit 20A, or control may be performed using a combination of the pressure sensor 55A, the first temperature sensor 26A, and the second temperature sensor 27A.

[0046] The adsorption by the hydrogen storage alloy 11A is terminated by closing the on-off valve 53A.

[0047] Next, desorption of hydrogen from the hydrogen storage alloy 11A will be described. Hydrogen in the hydrogen storage tank 10A is led to the hydrogen utilization device C through a flow path 52A by opening an on-off valve 54A.

[0048] When the hydrogen utilization device C starts up, the controller 60 desorbs hydrogen from the hydrogen storage alloy 11A to supply hydrogen to the hydrogen utilization device C. Specifically, the controller 60 first opens the on-off valve 54A. This allows hydrogen to be supplied from the hydrogen storage tank 10A to the hydrogen utilization device C. In this embodiment, the pressure of the hydrogen desorbed from the hydrogen storage alloy 11A is controlled to be constant at about 0.8 MPa.

[0049] When the hydrogen storage alloy 11A desorbs hydrogen, the temperature of the hydrogen storage alloy 11A drops due to an endothermic reaction. When the temperature of the hydrogen storage alloy 11A drops, the pressure of the hydrogen desorbed from the hydrogen storage alloy 11A drops, and the hydrogen stops being desorbed. Therefore, in this embodiment, the heating mechanism 40A is driven to heat the water circulating in the circulation circuit 20A, thereby heating the hydrogen storage alloy 11A.

[0050] Specifically, the controller 60 drives the pump 42 and opens the on-off valve 45A. The controller 60 also drives the pump 21A and controls the control valve 25A so that the entire amount of water circulating in the circulation circuit 20A passes through the bypass flow path 24A. As a result, the water in the circulation circuit 41A circulates, and the water in the circulation circuit 20A circulates while bypassing the cooling mechanism 30.

[0051] The water circulating in the circulation circuit 41A exchanges heat with the hydrogen utilization device C in the fourth heat exchange section 44, and is heated by the exhaust heat of the hydrogen utilization device C. Then, when the water heated in the fourth heat exchange section 44 reaches the third heat exchange section 43A, heat exchange occurs between the third heat exchange section 43A and the first heat exchange section 22A, and the water circulating in the circulation circuit 20A is heated. In this manner, in this embodiment, the hydrogen storage alloy 11A is heated using the exhaust heat of the hydrogen utilization device C.

[0052] If the temperature of the water circulating in the circulation circuit 20A becomes too high, the pressure of the hydrogen desorbed from the hydrogen storage alloy 11A increases. In this case, the controller 60 controls the on-off valve 45A to reduce the flow rate of the water passing through the third heat exchange section 43A. This reduces the amount of heat received by the first heat exchange section 22A from the third heat exchange section 43A, thereby suppressing the temperature rise of the water circulating in the circulation circuit 20A. This control is performed by performing feedback control based on the pressure detected by the pressure sensor 55A.

[0053] When the temperature of the water circulating in the circulation circuit 20A becomes too high, in addition to controlling the on-off valve 45A, the control valve 25A may be controlled so that a part of the water circulating in the circulation circuit 20A passes through the cooling mechanism 30. The water that has passed through the cooling mechanism 30 is cooled by the cooling mechanism 30 and merges with the water that has passed through the bypass flow path 24A. This makes it possible to lower the temperature of the water circulating in the circulation circuit 20A. Alternatively, only the control valve 25A may be controlled. Furthermore, the control may be performed using the first temperature sensor 26A and the second temperature sensor 27A provided in the circulation circuit 20A, or the control may be performed using the pressure sensor 55A in combination with the first temperature sensor 26A and the second temperature sensor 27A.

[0054] In the hydrogen energy system S, the hydrogen absorption system 100 includes two hydrogen storage tanks 10A, 10B. Therefore, when one of the hydrogen storage alloys 11A, 11B of the hydrogen storage tanks 10A, 10B is desorbing hydrogen, the other hydrogen storage alloy 11A, 11B can absorb hydrogen. This allows a stable supply of hydrogen to the hydrogen utilization device C. The number of hydrogen storage tanks may be three or more, or may be one as long as the requirements for the hydrogen energy system S are met.

[0055] However, for example, if the hydrogen utilization device C has been stopped for a long period of time, there is a risk that it will not be possible to heat the hydrogen storage alloys 11A, 11B because no exhaust heat is generated from the hydrogen utilization device C. Therefore, it is conceivable to provide a heat generating device such as a heater and use the heat generated by the heat generating device when the hydrogen utilization device C is started up to heat the hydrogen storage alloys 11A, 11B and desorb hydrogen from the hydrogen storage alloys 11A, 11B.

[0056] However, even if a heating device such as a heater is provided, if a power outage or other event occurs that makes it impossible to secure a power source to operate the heater, it may be impossible to heat the hydrogen storage alloys 11A and 11B and therefore impossible to desorb hydrogen from the hydrogen storage alloys 11A and 11B. As a result, hydrogen may not be supplied to the hydrogen utilization device C, and the hydrogen utilization device C may not be able to start up.

[0057] Therefore, the hydrogen storage system 100 of this embodiment is provided with a heating device 70 capable of heating the hydrogen storage alloys 11A, 11B without using electric power. The heating device 70 will be specifically described below.

[0058] As shown in FIG. 1, heating device 70 includes a heat generating unit 71 having a heat generating agent that generates heat by reacting with water, heating units 72A, 72B that heat hydrogen storage alloys 11A, 11B using heat generated by heat generating unit 71, a water tank 73 that stores water to be supplied to heat generating unit 71, an on-off valve 74 that allows or blocks the flow of water between heat generating unit 71 and water tank 73, and a heat transfer circuit 75 that transfers heat generated in heat generating unit 71 to heating units 72A, 72B.

[0059] The heat generating unit 71 has a heat generating agent (not shown) that generates heat by reacting with water or water vapor, and a container that contains the heat generating agent. As the heat generating agent, for example, a solid such as silica gel, zeolite, or calcium oxide, or an aqueous solution of lithium bromide (LiBr) or calcium chloride (CaCl2) is used.

[0060] The heating units 72A and 72B are provided in the hydrogen storage tanks 10A and 10B so as to be in contact with or located in the vicinity of the hydrogen storage alloys 11A and 11B, respectively.

[0061] The heat transfer circuit 75 has a circulation circuit 75A through which water circulates as a heat medium, a pump 75B for circulating the water within the circulation circuit 75A, and a fifth heat exchange section 75C that performs heat exchange with the heat generating section 71.

[0062] The circulation circuit 75A transfers the heat generated in the heat generating portion 71 to the heating portions 72A and 72B by the circulation of the water therein.

[0063] The pump 75B is driven by a motor (not shown). The type of the pump 75B is not particularly limited, but the pump 75B is constituted by a centrifugal pump, a gear pump, a vane pump, or the like.

[0064] The fifth heat exchanger 75C exchanges heat with the heat generating section 71, and heats the water circulating in the circulation circuit 75A with the heat generated by the heat generating section 71.

[0065] Next, a method of using the heating device 70 will be described.

[0066] The heating device 70 is started, for example, by an operator operating a switch. When the operator operates the switch, the controller 60 first opens the on-off valve 74. This causes water stored in the water tank 73 to be supplied to the heat generating unit 71. As a result, the heat generating agent contained in the container of the heat generating unit 71 reacts with the water supplied from the water tank 73 and generates heat. The on-off valve 74 is an electrically operated valve that is opened and closed by instructions from the controller 60.

[0067] The controller 60 drives the pump 75B when a predetermined time T has elapsed since the on-off valve 74 is opened. The predetermined time T is set to a time when it can be estimated that the heat generation temperature in the heat generating part 71 is equal to or higher than a predetermined temperature. Alternatively, the temperature of the heat generating part 71 may be measured and the pump 75B may be driven based on the measured temperature. Furthermore, if a sufficient amount of power for driving the pump 75B can be secured, the pump 75B may be driven simultaneously with the opening of the on-off valve 74.

[0068] When the pump 75B is driven, the water in the circulation circuit 75A circulates. The water circulating in the circulation circuit 75A exchanges heat with the heat generating unit 71 in the fifth heat exchange unit 75C, and is heated by the heat generated by the heat generating unit 71. When the water heated in the fifth heat exchange unit 75C reaches the heating units 72A and 72B, the hydrogen storage alloys 11A and 11B are heated. In this manner, in this embodiment, the heat generated in the heat generating unit 71 is used to heat the hydrogen storage alloys 11A and 11B.

[0069] Furthermore, since the amount of electricity required to drive the on-off valve 74 and the pump 75B is smaller than the amount of electricity required to heat the hydrogen storage alloys 11A, 11B using a heat generating device such as a heater, they can operate by receiving power from an emergency power source such as a battery even during a power outage.

[0070] In this way, by including the heating device 70, the hydrogen absorption system 100 can start the hydrogen utilization device C even in a situation in which the hydrogen storage alloys 11A, 11B cannot be heated, specifically, in a situation in which power cannot be supplied from the outside due to a power outage or the like. Once the hydrogen utilization device C is started, it becomes possible to generate power and to utilize the exhaust heat of the hydrogen utilization device C. This makes it possible to execute normal control.

[0071] The hydrogen storage system 100 according to the first embodiment configured as above provides the following advantageous effects.

[0072] The hydrogen absorption system 100 of this embodiment includes a heating device 70 having a heat generating unit 71 having a heat generating agent that generates heat by reacting with water, and heating units 72A, 72B that heat the hydrogen storage alloys 11A, 11B using the heat generated by the heat generating unit 71. Therefore, according to the hydrogen absorption system 100 of this embodiment, by heating the hydrogen storage alloys 11A, 11B using the heating device 70 without receiving power from an external source, it is possible to desorb hydrogen from the hydrogen storage alloys 11A, 11B and supply hydrogen to the hydrogen utilization device C. This allows the hydrogen utilization device C to be started reliably.

[0073] Furthermore, in the hydrogen absorbing system 100, the hydrogen absorbing alloys 11A, 11B are heated by exhaust heat generated during operation of the hydrogen utilization device C, so that energy efficiency can be improved.

[0074] When silica gel, zeolite, or an aqueous solution of lithium bromide (LiBr) or calcium chloride (CaCl2) is used as the heat generating agent, for example, after the hydrogen utilization device C is started using the heating device 70, the heat generating part 71 can be heated using a heater or heat generated in the hydrogen storage alloys 11A, 11B, to dry the heat generating agent. Although not shown, in this case, a return passage for returning water vapor from the heat generating part 71 to the water tank 73 is provided between the heat generating part 71 and the water tank 73. By reusing the heat generating agent in this way, the heating device 70 can be used repeatedly.

[0075] <Second embodiment> Next, a hydrogen absorption system 200 according to a second embodiment will be described with reference to Fig. 3. Only the differences from the hydrogen absorption system 100 according to the first embodiment will be described below, and the same components will be denoted by the same reference numerals and description thereof will be omitted.

[0076] The hydrogen absorption system 200 according to the second embodiment includes a heating device 170 instead of the heating device 70 of the hydrogen absorption system 100 according to the first embodiment.

[0077] As shown in FIG. 3, the heating device 170 includes heat generating parts 171A, 171B having a heat generating agent that generates heat by reacting with water, a water tank 73 that stores water to be supplied to the heat generating parts 171A, 171B, a connection flow path 175 that connects the heat generating parts 171A, 171B and the water tank 73, and an opening / closing valve 74 provided in the connection flow path 175 that allows or blocks the flow of water between the heat generating parts 171A, 171B and the water tank 73.

[0078] The heat generating units 171A and 171B each have a heat generating agent (not shown) that generates heat by reacting with water, and a container that the heat generating agent is stored in. As the heat generating agent, for example, a solid such as silica gel, zeolite, or calcium oxide, or an aqueous solution of lithium bromide (LiBr) or calcium chloride (CaCl2) is used.

[0079] The heat generating portions 171A and 171B are provided in the hydrogen storage tanks 10A and 10B so as to be in contact with or located in the vicinity of the hydrogen storage alloys 11A and 11B, respectively.

[0080] Next, a method of using the heating device 170 will be described.

[0081] The heating device 170 is started, for example, by an operator operating a switch. When the operator operates the switch, the controller 60 opens the on-off valve 74. As a result, water stored in the water tank 73 is supplied to the heat generating units 171A and 171B through the connecting flow path 175. As a result, the heat generating agent contained in the containers of the heat generating units 171A and 171B reacts with the water supplied from the water tank 73 and generates heat.

[0082] When heat is generated by the heat generating parts 171A, 171B, the hydrogen storage alloys 11A, 11B are heated by the generated heat. In this manner, also in this embodiment, the hydrogen storage alloys 11A, 11B can be heated by using the heat generated by the heat generating parts 171A, 171B. Note that in this embodiment, the heat generating parts 171A, 171B serve as both the "heat generating part" and the "heating part" in the claims.

[0083] The hydrogen absorption system 200 according to the second embodiment configured as above provides the following advantageous effects in addition to the advantageous effects of the hydrogen absorption system 100 according to the first embodiment.

[0084] In the hydrogen absorption system 200, the heating device 170 does not include the pump 75B, so that it is possible to reduce the amount of power consumed when driving the heating device 170. This allows the battery to be made smaller. Furthermore, not using a pump allows costs to be reduced.

[0085] Furthermore, if the on-off valve 74 is of a manual type, the hydrogen storage alloys 11A, 11B can be heated even without a power source. Furthermore, if the on-off valves 54A, 54B are configured to be manually operable, hydrogen can be supplied to the hydrogen utilization device C even without a power source.

[0086] As described above, by providing the hydrogen absorption system 100, the hydrogen utilization device C can be started to generate power without receiving power from an external source. Therefore, the hydrogen energy system S can be used as an emergency power generation facility, more specifically, as an emergency power generation facility for avoiding, for example, a power outage in the power grid.

[0087] Although the embodiments of the present invention have been described above, the above-mentioned embodiments merely show some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above-mentioned embodiments.

[0088] In the above embodiment, the heating devices 70, 170 are configured to heat both the hydrogen storage alloys 11A, 11B, but the present invention is not limited to this, and only one of the hydrogen storage alloys 11A, 11B may be heated.

[0089] In the above embodiment, the heating mechanisms 40A, 40B are described as being configured to heat the water flowing through the circulation circuits 41A, 41B using exhaust heat from the hydrogen utilization device C, but the present invention is not limited to this. The heating mechanisms 40A, 40B may be heaters that directly heat the water circulating in the circulation circuits 20A, 20B. In addition, if a chiller or the like capable of heating and cooling the water circulating in the circulation circuits 20A, 20B is provided, the heating mechanisms 40A, 40B may not be provided. From the viewpoint of energy saving, it is preferable to employ the heating mechanisms 40A, 40B that utilize exhaust heat generated in the hydrogen utilization device C as in the above embodiment.

[0090] In the above embodiment, water has been described as an example of the fluid flowing through the circulation circuits 20A and 20B, but this is not limiting. When a radiator, chiller, or the like is used as the cooling mechanism 30, the circulation circuits 20A and 20B can be isolated from the outside, so that a fluid other than water can be used.

[0091] Furthermore, in the above embodiment, an example has been described in which pump 21A is driven so that the discharge flow rate is constant during adsorption, but this is not limiting, and the discharge flow rate of pump 21A may be changed in response to changes in the hydrogen pressure or temperature.

[0092] In the above embodiment, the pressure is controlled to be constant, but the pressure may be controlled to be within a predetermined range. In addition, if the cooling temperature can be lowered, the pressure during adsorption may be set lower than 0.8 MPa.

[0093] A pressure adjusting device such as a pressure reducing valve may be provided at the inlet of the hydrogen utilization device C. In addition, in the embodiment shown in Fig. 1 and the like, for convenience, the heat exchanger formed by the first heat exchange section 22A and the third heat exchange section 43A is described as a parallel flow type, and the heat exchanger formed by the first heat exchange section 22B and the third heat exchange section 43B is described as a counterflow type, but either the parallel flow type or the counterflow type can be used.

[0094] In the above embodiment, the hydrogen generation device P has been described as an electrolysis device that generates hydrogen by electrolyzing water. However, the hydrogen generation device P is not limited to a fixed device such as an electrolysis device, and may be a mobile device such as a hydrogen trailer.

[0095] In the above embodiment, the heating device 70 is started by an operator operating a switch or the like. However, the heating device 70 may be configured to be started automatically by the controller 60. [Explanation of symbols]

[0096] 100,200···Hydrogen storage system S...Hydrogen Energy System P... Hydrogen generator C Hydrogen Utilization Device 10A, 10B: Hydrogen storage tank 11A, 11B: Hydrogen storage alloy 20A,20B...Circulation circuit 30...Cooling mechanism 40A,40B...Heating mechanism 70,170...Heating device 71,171... Heat generating part 72A,72B...Heating part 73 Water tank 74...Shut-off valve 75...Heat transfer circuit 171A, 171B Heat generating part (heating part)

Claims

1. a hydrogen storage alloy that stores hydrogen to be supplied to a hydrogen utilization device; A heat generating unit having a heat generating agent that generates heat by reacting with water; a heating section that heats the hydrogen storage alloy with heat generated by the heat generating section at the time of startup of the hydrogen storage system.

2. 2. The hydrogen storage system according to claim 1, A hydrogen storage system, wherein the heat generating agent is reusable.

3. 2. The hydrogen storage system according to claim 1, The heat generating agent is heated by heat generated by the hydrogen storage alloy, thereby regenerating the hydrogen storage system.

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