JP2008239440A - Apparatus for generating and controlling hydrogen - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for generating and controlling hydrogen which can generate a large amount of hydrogen rapidly. <P>SOLUTION: The apparatus holds hydride 50 in a vessel 51 as a powder form. When generating hydrogen, a heat medium 61 that is composed of a polar and nonaqueous material is supplied into the vessel 51, and the temperature of the hydride 50 is forced to raise to its thermal cracking temperature or higher by heating the heat medium 61 with a heating device 69. When stopping the generation of hydrogen, the temperature of the hydride 50 is forced to lower below its thermal cracking temperature by discharging the heat medium 61 having a high temperature from the inside of the vessel 51 and by supplying a heat medium 61 having a low temperature into the vessel 51. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hydrogen generation control device.

  Various hydrogen generators are known as a hydrogen supply source for a fuel cell that obtains electric power by reacting hydrogen and oxygen (see Patent Documents 1 and 2, etc.). In these hydrogen generators, a catalyst is heated by a burner or an electric heater, and hydrogen is generated by bringing a raw material gas or a hydride into contact with the catalyst.

Japanese Patent No. 3408521 JP 2004-192834 A

  However, in these hydrogen generators, a large amount of catalyst is required to generate a large amount of hydrogen, and a long time is required to sufficiently raise the temperature of the entire large amount of catalyst. There is a problem that it is difficult to quickly generate.

  In order to solve the above-described problems, according to the present invention, when a hydride is accommodated in a container and hydrogen is to be generated, a preheated heat medium is allowed to flow into the container or the heat medium is placed in the container. The hydride is heated to a temperature equal to or higher than its thermal decomposition temperature by heating the heating medium after flowing into the reactor, and when the generation of hydrogen is to be stopped, There is provided a hydrogen generation control device in which the temperature of a compound is lower than its thermal decomposition temperature.

  A large amount of hydrogen can be generated quickly.

  FIG. 1 shows a case where the present invention is applied to a power generation system.

  Referring to FIG. 1, the power generation system 1 includes a fuel cell 10, an oxygen supply device 20 that supplies oxygen to the fuel cell 10, a hydrogen supply device 30 that supplies hydrogen to the fuel cell 10, and an electronic control unit 40. To do.

  The oxygen supply device 20 includes an oxygen source 21 such as the atmosphere, an oxygen supply pipe 22 that supplies oxygen from the oxygen source 21 to the fuel cell 10, an oxygen pump 23 disposed in the oxygen supply pipe 22, an oxygen pump 23, And an oxygen supply valve 24 including an electromagnetic valve disposed in the oxygen supply pipe 22 between the fuel cells 10.

  The hydrogen supply device 30 includes a hydrogen generator 31 that is a hydrogen source, a hydrogen supply pipe 32 that supplies hydrogen from the hydrogen generator 31 to the fuel cell 10, and a hydrogen buffer that is disposed in the hydrogen supply pipe 32 and stores hydrogen at a high pressure. 33, a hydrogen supply valve 34 comprising an electromagnetic valve disposed in the hydrogen supply pipe 32 between the hydrogen buffer 33 and the fuel cell 10, and a hydrogen supply pipe 32 between the hydrogen generator 31 and the hydrogen buffer 33. And a hydrogen discharge valve 35 comprising a check valve. A pressure sensor 36 for detecting the pressure in the hydrogen buffer 33 is attached to the hydrogen buffer 33. This pressure represents the amount of hydrogen stored in the hydrogen buffer 33.

  The hydrogen generator 31 includes a hydride 50 and a temperature controller 60 that controls the temperature of the hydride 50.

The hydride 50 is accommodated in a container 51, and the above-described hydrogen supply pipe 32 is connected to the top of the container 51. In the embodiment according to the present invention, the hydride 50 is composed of a thermal decomposition type inorganic hydride. The hydride 50 is thermally decomposed to generate hydrogen H ₂ when its temperature is equal to or higher than the thermal decomposition temperature. When the temperature is lower than the thermal decomposition temperature, thermal decomposition does not occur, that is, generation of hydrogen is stopped. Since the thermal decomposition temperature is determined by the composition of the hydride 50, it cannot be determined in general. However, in the embodiment according to the present invention, a hydride having a relatively low thermal decomposition temperature, for example, about 100 to 150 ° C. is used. The hydride 50 can be used in the form of a fluid such as gas and liquid. However, in the embodiment according to the present invention, the hydride 50 is accommodated in the container 51 in the form of a solid, for example, powder. This facilitates separation of the hydride 50 from the generated hydrogen gas and the heat medium. Examples of hydrides that satisfy these conditions include NaAlH ₄ , LiAlH ₄ , Mg (AlH ₄ ) ₂ , and AlH ₃ . Furthermore, a temperature sensor 52 for detecting the temperature of the hydride 50 is attached to the container 51.

  The temperature control device 60 includes a heat medium 61 that heats the hydride 50, a heat medium tank 62 that stores the heat medium 61, a heat medium supply pipe 63 that supplies the heat medium 61 from the heat medium tank 62 to the container 51, and heat A heat medium supply valve 64 including an electromagnetic valve disposed in the medium supply pipe 63, a heat medium return pipe 65 that discharges the heat medium 61 out of the container 51 and returns the heat medium tank 62 to the heat medium tank 62, and the heat medium return pipe 65 A heat medium discharge valve 66 including a solenoid valve disposed, a cooling device 67 disposed in the heat medium return pipe 65 and capable of cooling the heat medium 61, and a heat medium pump 68 disposed in the heat medium return pipe 65. And a heating device 69 capable of heating the heat medium 61. In the embodiment according to the present invention, the heating device 69 includes a heating container or an oven 69a that accommodates the container 51 in a replaceable manner, and a dielectric heating device 69b such as a magnetron disposed in the heating container 69a. A filter 70 is disposed between the hydride 50 and the heat medium return pipe 65.

  The heat medium 61 is made of a polar material. Further, the heat medium 61 is made of a non-aqueous material so as not to cause a hydrolysis reaction with the hydride 50. Further, the heat medium 61 is made of a material whose boiling point is sufficiently higher than the thermal decomposition temperature of the hydride 50 and whose freezing point is sufficiently lower than room temperature, and thus remains liquid throughout the process. This facilitates separation of the heat medium 61 from the hydride 50 and the generated hydrogen gas. In the embodiment according to the present invention, since the thermal decomposition temperature of the hydride 50 is about 100 to 150 ° C., a heating medium having a boiling point of, for example, 200 ° C. or more is used. Examples of the heat medium that satisfies these conditions include ethylene carbonate and propylene carbonate. A gas or solid heat medium 61 can also be used.

  Various configurations of the cooling device 67 are conceivable. In the embodiment according to the present invention, as shown in FIG. 2, the cooling device 67 includes a bypass pipe 67a branched from the heat medium return pipe 65 and reaching the heat medium return pipe 65, and a radiator disposed in the bypass pipe 67a. 67b and a three-way valve 67c made of an electromagnetic valve. When the cooling device 67 is to be operated, the three-way valve 67c is controlled so that the heat medium 61 is guided into the radiator 67b and then returned to the heat medium return pipe 65 downstream of the three-way valve 67c. In contrast, when the operation of the cooling device 67 is to be stopped, the three-way valve 67c is controlled so that the heat medium 61 flows through the heat medium return pipe 65 while bypassing the radiator 67b.

  The electronic control unit 40 is composed of a digital computer, and is connected to each other by a bidirectional bus 41. A ROM (read only memory) 42, a RAM (random access memory) 43, a CPU (microprocessor) 44, an input port 45 and an output port 46 are connected. It comprises. The output voltages of the pressure sensor 36 and the temperature sensor 52 are input to the input port 45 via the corresponding AD converters 47, respectively. The output port 46 is connected to the oxygen pump 23, the oxygen supply valve 24, the hydrogen supply valve 34, the heat medium supply valve 64, the heat medium discharge valve 66, the cooling device 67 through the three-way valve 67c, and the heat medium pump 68 via the corresponding drive circuit 48. , And the heating device 69, which are controlled based on signals from the electronic control unit 40, respectively.

  The oxygen pump 23, the oxygen supply valve 24, the hydrogen supply valve 34, the heat medium supply valve 64, the heat medium discharge valve 66, the cooling device 67 to the three-way valve 67c, the heat medium pump 68, and the heating device 69 are, for example, fuel cells. It is operated with the electric power generated by 10.

  When the fuel cell 10 is to generate power, the oxygen supply valve 24 is opened, the oxygen pump 23 is operated, and the hydrogen supply valve 34 is opened. As a result, oxygen or air from the oxygen source 21 is supplied to the fuel cell 10 via the oxygen supply pipe 22, and hydrogen in the hydrogen buffer 33 is supplied to the fuel cell 10 via the hydrogen supply pipe 32.

  On the other hand, when hydrogen is to be generated by the hydrogen generator 31, that is, for example, when the pressure in the hydrogen buffer 33 has dropped below the allowable lower limit, the hydrogen generator 31 is activated. As a result, the generated hydrogen is supplied from the hydrogen generator 31 to the hydrogen buffer 33. In this case, in the embodiment according to the present invention, the hydrogen generation operation in the hydrogen generator 31 is performed as follows.

  That is, first, the heat medium supply valve 64 is opened in a state where the heat medium discharge valve 66 is closed, and as a result, the room temperature heat medium 61 is supplied from the heat medium tank 62 into the container 51. Next, when the heat medium 61 is supplied into the container 51 by a preset amount, for example, an amount necessary for immersing almost the entire hydride 50 in the container 51, the heat medium supply valve 64 is closed. Then, the supply of the heat medium 61 is stopped. Next, the heating device 69 is operated, and the heat medium 61 in the container 51 is dielectrically heated. As a result, the hydride 50 is also heated, and when the temperature of the hydride 50 becomes equal to or higher than its thermal decomposition temperature, thermal decomposition of the hydride 50 occurs, that is, hydrogen is generated. The generated hydrogen is supplied into the hydrogen buffer 33 through the hydrogen supply pipe 32. Note that when hydrogen is to be generated, oxygen and hydrogen may be supplied to the fuel cell 10 to generate electric power in the fuel cell 10, and the heating device 69 and the like may be operated with the electric power generated at this time.

  Next, when the temperature of the hydride 50 exceeds an allowable upper limit (for example, 150 ° C.), the heating device 69 is stopped, and thus the heating of the heat medium 61 is stopped. Even when the heating of the heat medium 61 is stopped, hydrogen continues to be generated as long as the temperature of the hydride 50 is equal to or higher than the thermal decomposition temperature. Next, when it is time to stop the hydrogen generation operation of the hydrogen generator 31, that is, for example, when the pressure in the hydrogen buffer 33 reaches the required pressure, the heat medium discharge valve 66 is opened and the heat medium pump 68 is operated. The As a result, the high temperature heat medium 61 is discharged from the container 51, and the hydride 50 does not come into contact with the high temperature heat medium 61. Therefore, the temperature of the hydride 50 can be lowered quickly. At this time, the cooling device 67 is operated, and as a result, the heat medium 61 is returned to the heat medium tank 62 after being cooled to room temperature, for example. At this time, the heat medium supply valve 64 is opened, and an unheated normal or low temperature heat medium 61 in the heat medium tank 62 is supplied into the container 51. As a result, the hydride 50 is cooled more rapidly. In this way, the heat medium 61 is circulated.

  Next, when the temperature of the hydride 50 becomes lower than the thermal decomposition temperature and the hydrogen generating action is stopped, the circulation of the heat medium 61 is stopped. Specifically, first, the heat medium supply valve 64 is closed, and the supply of the heat medium 61 to the container 51 is stopped. Next, when there is almost no heat medium 61 in the container 51, the heat medium discharge valve 66 is closed, the heat medium pump 68 is deactivated, and the cooling device 67 is deactivated. In this case, a set amount of the heat medium 61 may remain in the container 51. This eliminates the need to supply the heat medium 61 into the container 51 the next time hydrogen is to be generated.

  As described above, in the embodiment according to the present invention, the heat medium 61 is made of a polar material and the heat medium 61 is dielectrically heated. Therefore, the temperature of the entire heat medium 61 can be quickly raised. In addition, since the heat medium 61 is in contact with almost the entire hydride 50, the temperature of the entire hydride 50 can be raised quickly, and thus a large amount of hydrogen can be generated quickly. Further, since the hydride 50 is heated not directly but indirectly through the heat medium 61, the heating of the hydride 50 can be stopped by simply discharging the heat medium 61 from the container 51, and therefore Hydrogen generation can be stopped quickly. In addition, since the low-temperature heat medium 61 is supplied into the container 51, hydrogen generation can be stopped more rapidly.

  In fact, according to the embodiment of the present invention, the time required for raising the temperature of the hydride 50 to the allowable upper limit is reduced to about 3/4 compared with the case where the heat medium is heated using the heat exchanger. It has been confirmed that the time required for lowering the temperature of the hydride 50 to be lower than the thermal decomposition temperature can be shortened to about 30 to 60%.

  FIG. 3 shows a hydrogen generation control routine of the embodiment according to the present invention. This routine is executed at predetermined time intervals.

  Referring to FIG. 3, first, at step 100, it is judged if hydrogen should be generated. When it is determined that hydrogen should not be generated, the processing cycle ends. When it is determined that hydrogen should be generated, the process proceeds to step 101 where the heat medium 61 is supplied into the container 51 by a set amount. In the subsequent step 102, the heat medium 61 in the container 51 is heated. In the following step 103, it is determined whether or not the temperature T of the hydride 50 has exceeded the allowable upper limit TUL. When T ≦ TUL, the routine jumps to step 105. On the other hand, when T> TUL, the routine proceeds to step 104 where heating of the heat medium 61 is stopped. Next, the routine proceeds to step 105. In step 105, it is determined whether or not the pressure P in the hydrogen buffer 33 has reached the required pressure PRQ. When P <PRQ, the routine returns to step 103, and when P ≧ PRQ, the routine proceeds to step 106. In step 106, the high-temperature heat medium 61 is discharged from the container 51, cooled, and returned to the heat medium tank 62. A low-temperature heat medium 61 is supplied into the container 51. In the following step 107, it is determined whether or not the temperature T of the hydride 50 has become lower than its thermal decomposition temperature TDH. When T ≧ TDH, the routine returns to step 106, and when T <TDH, the routine proceeds to step 108 where supply, discharge and cooling of the heat medium 61 are stopped.

  As can be seen from the above description, it is preferable that the amount of the heat medium 61 used is as large as possible in view of promptly lowering the temperature of the hydride 50. However, the capacity of the heat medium tank 62 is also limited. Therefore, in the embodiment according to the present invention, the amount of the heat medium 61 used is set to about twice the set amount described above.

  Next, another embodiment according to the present invention will be described.

  In the above-described embodiment according to the present invention, when the hydrogen is to be generated, the heating medium 61 is supplied into the container 51 by a set amount and heated. On the other hand, in another embodiment according to the present invention, the heat medium 61 is circulated and the heat medium 61 in the container 51 is heated by the heating device 69.

  FIG. 4 shows a hydrogen generation control routine of another embodiment according to the present invention. This routine is executed at predetermined time intervals.

  Referring to FIG. 4, first, at step 200, it is judged if hydrogen should be generated. When it is determined that hydrogen should not be generated, the processing cycle is terminated. When it is determined that hydrogen should be generated, the routine proceeds to step 201 where the heat medium 61 is circulated and heated. That is, the heat medium supply valve 64 and the heat medium discharge valve 66 are opened, the heat medium pump 68 is activated, and the heating device 69 is activated. As a result, the heat medium 61 is supplied from the heat medium tank 62 into the container 51 and returned from the container 51 to the heat medium tank 62 via the heat medium return pipe 65. At the same time, the heat medium 61 in the container 51 is heated and the hydride 50 is heated. At this time, the heat medium 61 is circulated so that almost the entire hydride 50 in the container 51 continues to be immersed in the heat medium 61. At this time, the cooling device 67 is stopped.

  In the following step 202, it is determined whether or not the temperature T of the hydride 50 has exceeded the allowable upper limit TUL. When T ≦ TUL, the routine jumps to step 204. On the other hand, when T> TUL, the routine proceeds to step 203 where heating of the heat medium 61 is stopped. That is, the heating device 69 is deactivated. Next, the routine proceeds to step 204. In step 204, it is determined whether or not the pressure P in the hydrogen buffer 33 has reached the required pressure PRQ. When P <PRQ, the routine returns to step 201, and when P ≧ PRQ, the routine proceeds to step 205. In step 205, the heat medium 61 is cooled while the circulation of the heat medium 61 is continued. In the next step 206, it is determined whether or not the temperature T of the hydride 50 has become lower than its thermal decomposition temperature TDH. When T ≧ TDH, the process returns to step 205, and when T <TDH, the process proceeds to step 207, where the circulation and cooling of the heat medium 61 are stopped. That is, the heat medium supply valve 64 and the heat medium discharge valve 66 are closed, and the heat medium pump 68 and the cooling device 67 are deactivated.

  FIG. 5 shows another embodiment of the hydrogen supply device 30.

  In the embodiment shown in FIG. 5, the internal space of the container 51 is divided into a plurality of, for example, 2 to 10 cells 51a. The inflow ends of the hydrogen supply pipes 32 are branched into the same number of hydrogen supply branch pipes 32a as the cells 51a, and these hydrogen supply branch pipes 32a are respectively connected to the corresponding cells 51a. Similarly, the outflow end of the heat medium supply pipe 63 is branched into the same number of heat medium supply branch pipes 63a as the cells 51a, and the inflow end of the heat medium return pipe 65 is branched into the same number of heat medium return branch pipes 65a as the cells 51a. The heat medium supply branch pipe 63a and the heat medium return branch pipe 65a are connected to the corresponding cells 51a. Further, individual heat medium supply valves 64a made of electromagnetic valves are arranged in the heat medium supply branch pipe 63a, and individual heat medium discharge valves 66a made of electromagnetic valves are arranged in the heat medium return branch pipe 65a. Is done. Although only one is shown in FIG. 5, a temperature sensor 52a for detecting the temperature of the hydride 50 in each cell 51a is attached to each cell 51a. An individual filter 70a is disposed between the hydride 50 in each cell 51a and the corresponding heat medium return branch pipe 65a.

  A heating device 69 is disposed in the heat medium supply pipe 63 upstream of the heat medium supply valve 64a. This heating device 69 has a heating container 69a for receiving the heating medium 61, a dielectric heating device 69b for heating the heating medium 61 in the heating container 69a, and a heating medium inflow comprising an electromagnetic valve attached to the inlet of the heating container 69a. It includes a valve 69c, a heat medium outflow valve 69d composed of an electromagnetic valve attached to the outlet of the heating container 69a, and a temperature sensor 69e for detecting the temperature of the heat medium 61 in the heating container 69a.

  In the embodiment shown in FIG. 5, the hydrogen generating action is performed as follows.

  That is, when hydrogen is to be generated, first, the heat medium 61 is preset from the heat medium tank 62 by a predetermined amount, for example, an amount necessary for immersing almost the entire hydride 50 in the single cell 51a. It is supplied into the heating container 69 a of the heating device 69. Specifically, the heat medium inflow valve 69c is opened with the heat medium outflow valve 69d closed, and the heat medium inflow valve 69c is closed when the heat medium 61 is filled into the heating container 69a by a set amount. To be spoken. Next, the dielectric heating device 69b is activated, and the heat medium 61 in the heating container 69a is heated. In this case, the heating medium 61 is heated to a temperature (for example, 200 ° C.) necessary for the hydride 50 that has come into contact with the heating medium 61 to have a temperature higher than the thermal decomposition temperature thereafter.

  Next, the heated heat medium 61 in the heating device 69 is supplied to one of the cells 51a. Specifically, the corresponding heat medium supply valve 64a is temporarily opened while the heat medium outlet valve 69d is opened and the corresponding heat medium discharge valve 66a is closed. As a result, the high-temperature heat medium 61 is supplied to the cell 51a, the hydride 50 in the cell 51a is heated to a temperature equal to or higher than its thermal decomposition temperature, and hydrogen is thus generated. The generated hydrogen is supplied into the hydrogen buffer 33 through the corresponding hydrogen supply branch pipe 32 a and the hydrogen supply pipe 32.

  Next, the heat medium 61 is newly supplied from the heat medium tank 62 to the heating device 69 and heated, and the high-temperature heat medium 61 is supplied into another cell 51a. As a result, hydrogen is also generated in another cell 51a. In this manner, the heat medium 61 is sequentially heated by a set amount, and the high-temperature heat medium 61 is sequentially supplied to the cells 51a.

  Next, when it is time to stop the hydrogen generation operation, that is, for example, when the pressure in the hydrogen buffer 33 reaches the required pressure, the heat medium discharge valve 66a of the cell 51a supplied with the heat medium 61 is opened, and the heat medium Pump 62 is activated. As a result, the high-temperature heat medium 61 is discharged from the cell 51a, and the hydride 50 in the cell 51a is quickly cooled. At this time, the cooling device 67 is operated, so that the heat medium 61 is returned to the heat medium tank 62 after being cooled to room temperature, for example. At this time, the dielectric heating device 69b of the heating device 69 is deactivated, and the low-temperature heat medium 61 is supplied to the cell 51a to which the high-temperature heat medium 61 is supplied, so that the heat medium 61 is circulated. Specifically, the heat medium inflow valve 69c and the heat medium outflow valve 69d of the heating device 69 are opened, and the heat medium supply valves 64a corresponding to the cells 51a to which the high temperature heat medium 61 is supplied are sequentially and temporarily opened. To be spoken. As a result, the temperature of the hydride 50 is further lowered.

  Next, when the temperature of the hydride 50 in all the cells 51a becomes lower than the thermal decomposition temperature and the hydrogen generating action is stopped, the circulation of the heat medium 61 is stopped. Specifically, first, the heat medium inflow valve 69c and the heat medium outflow valve 69d of the heating device 69 are closed, and all the heat medium supply valves 64a are closed. Next, when there is almost no heat medium 61 in all the cells 51a, all the heat medium discharge valves 66 are closed, the heat medium pump 68 is deactivated, and the cooling device 67 is deactivated.

  In this manner, in the embodiment shown in FIG. 5, the hydride 50 is subdivided into the plurality of cells 51a, so that the hydride 50 in one cell 51a can be rapidly heated or lowered. In fact, according to the embodiment shown in FIG. 5, the time required to raise the temperature of the hydride 50 to the allowable upper limit can be reduced to about 13%, compared with the embodiment of FIG. It has been confirmed that the time required for lowering the temperature of the hydride 50 to be lower than the thermal decomposition temperature can be shortened to about 2/3.

  FIG. 6 shows a hydrogen generation control routine of the embodiment shown in FIG. This routine is executed at predetermined time intervals.

  Referring to FIG. 6, first, at step 300, it is judged if hydrogen should be generated. When it is determined that hydrogen should not be generated, the processing cycle is terminated. When it is determined that hydrogen should be generated, the routine proceeds to step 301 where the heat medium 61 is supplied to the heating device 69 by a set amount and heated. . In the subsequent step 302, the heated heat medium 61 is supplied to one of the cells 51a. In the next step 303, it is determined whether or not the pressure P in the hydrogen buffer 33 has reached the required pressure PRQ. When P <PRQ, the process returns to step 301, and the heated heat medium 61 is supplied to another cell 51a. When P ≧ PRQ, the routine proceeds from step 303 to step 304. In step 304, the high-temperature heat medium 61 is discharged from the cell 51a, cooled, and returned to the heat medium tank 62. Further, a low-temperature heat medium 61 is supplied into the cell 51a. In the following step 305, it is determined whether or not the temperature T of the hydride 50 in all the cells 51a has become lower than the thermal decomposition temperature TDH. When T ≧ TDH, the process returns to step 304. When T <TDH, the process proceeds to step 306, where the supply, discharge, and cooling of the heat medium 61 are stopped.

  In the embodiment shown in FIG. 5, the heat medium 61 is supplied to the heating device 69 and heated, but the heat medium 61 in the heat medium tank 62 may be heated. Other configurations and operations of the hydrogen supply apparatus 30 shown in FIG. 5 are the same as those of the hydrogen supply apparatus 30 shown in FIG.

1 is an overall view of a power generation system. It is detail drawing of a cooling device. It is a flowchart for performing a hydrogen generation control routine. It is a flowchart for performing the hydrogen generation control routine of another Example by this invention. It is a general view of another Example of a hydrogen supply apparatus. It is a flowchart for performing the hydrogen generation control routine of the Example shown by FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Power generation system 30 Hydrogen supply apparatus 31 Hydrogen generator 50 Hydride 51 Container 61 Heat medium 69 Heating apparatus

Claims (7)

  When hydride is contained in a container and hydrogen is to be generated, either a preheated heat medium is allowed to flow into the container, or a heat medium is allowed to flow into the container and then the heat medium is heated. When the temperature of the hydride is set to be equal to or higher than the thermal decomposition temperature and the generation of hydrogen is to be stopped, the temperature of the hydride is made lower than the thermal decomposition temperature by allowing the heat medium to flow out from the vessel. The hydrogen generation control device.   When the generation of hydrogen is to be stopped, the heat medium is caused to flow out of the container, and an unheated heat medium is allowed to flow into the container so that the temperature of the hydride becomes lower than its thermal decomposition temperature. Item 2. The hydrogen generation control device according to Item 1.   The hydrogen generation control device according to claim 2, wherein when the generation of hydrogen is to be stopped, the heat medium flowing out from the container is cooled and then returned to the container.   2. The hydrogen generation control device according to claim 1, wherein the heat medium is made of a polar material, and when the hydrogen is to be generated, the heat medium is heated by dielectric heating.   The hydrogen generation control device according to claim 1, wherein the heat medium is made of a non-aqueous material.   2. The hydrogen generation control device according to claim 1, wherein when hydrogen is to be generated, the heat medium is caused to flow into the container so that substantially the entire hydride in the container is immersed in the heat medium.   2. The hydrogen generation control device according to claim 1, wherein the hydride is accommodated in the container in the form of powder.

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