Hydrogen production device

Abstract

A hydrogen production device (10) has a reactor (12) that thermally decomposes a hydrocarbon gas, which is a raw material gas, using a catalyst (14), which is metal fine particles, to produce hydrogen, wherein a fluidized bed of the catalyst is formed inside the reactor by introducing the raw material gas from a lower part of the reactor. The catalyst is mixed with a fluidizing agent (17) which is inert particles for enhancing the fluidity of the catalyst.

Description

Hydrogen production equipment

[0001] The present disclosure relates to a hydrogen production device.

[0002] Conventionally, there are known techniques for producing hydrogen by thermal decomposition of methane. For example, a hydrogen production apparatus disclosed in Patent Document 1 has a reactor containing a catalyst. Methane is introduced into the reactor. The methane is decomposed into hydrogen and carbon by contacting with the catalyst inside the reactor. A mixture of hydrogen, which is the product gas, and unreacted methane is taken out of the reactor.

[0003] Japanese Patent Application Laid-Open No. 2019-73411

[0004] The catalyst is a metal such as iron. In this case, for example, when the hydrogen production device is started up, the temperature of the reactor rises, and there is a risk that the catalyst may fuse together. The hydrogen production device is required to prevent the catalyst from fusing together.

[0005] A hydrogen production apparatus according to one aspect of the present disclosure is a reactor that produces hydrogen by thermally decomposing a hydrocarbon gas as a raw material gas using a catalyst made of fine metal particles, and includes a reactor into which the raw material gas is introduced from the bottom to form a fluidized bed of the catalyst. The catalyst is mixed with a fluidizing material made of inert particles to increase the fluidity of the catalyst.

[0006] Fig. 1 is a configuration diagram of a first embodiment of a hydrogen production device. Fig. 2 is a block diagram showing the electrical configuration of the hydrogen production device of Fig. 1. Fig. 3 is a configuration diagram of a second embodiment of a hydrogen production device.

[0007] <First embodiment> A first embodiment of a hydrogen production device will be described below. As shown in Fig. 1, the hydrogen production device 10 includes a pressure vessel 11 and a reactor 12. The pressure vessel 11 and the reactor 12 are each cylindrical with a circular cross section and extend in the vertical direction. The interior of the pressure vessel 11 is maintained at a predetermined pressure. The pressure is, for example, higher than atmospheric pressure. The reactor 12 is accommodated inside the pressure vessel 11 in a non-contact state. The inner diameter of the reactor 12 may be constant along its entire length.

[0008] A disperser 13 is provided inside the reactor 12. The disperser 13 is, for example, in the shape of a plate extending in a direction perpendicular to the axial direction of the reactor 12, and has a large number of holes. The holes penetrate the disperser 13 in the plate thickness direction. The disperser 13 is disposed at a position closer to the lower end of the reactor 12 than the axial center position of the reactor 12. The disperser 13 divides the inside of the reactor 12 into two spaces, an upper space and an lower space. The upper space is the reaction chamber 12A, and the lower space is the air chamber 12B. The reaction chamber 12A and the air chamber 12B are in communication with each other via the holes in the disperser 13.

[0009] The catalyst 14 is deposited on the upper surface of the disperser 13. That is, the inside of the reaction chamber 12A is filled with the catalyst 14 up to a predetermined deposition height relative to the disperser 13. The upper surface is the surface of the disperser 13 on the reaction chamber 12A side. The catalyst 14 is, for example, iron (Fe) or fine solid particles containing iron as a main component, i.e., metal particles. The catalyst 14 is heated by a heating device. The heating device is, for example, a heater or a jacket through which exhaust gas or steam flows.

[0010] An inlet pipe 15 is connected to the lower end of the reactor 12. The inlet pipe 15 penetrates the lower end of the pressure vessel 11. The inlet pipe 15 is a gas flow path for introducing a raw material gas into the reactor 12. The raw material gas is a hydrocarbon gas. The hydrocarbon gas is, for example, methane or a gas containing methane as a main component. The hydrocarbon gas is decomposed into hydrogen and carbon by coming into contact with the catalyst 14 inside the reactor 12. The carbon is in powder form.

[0011] An outlet pipe 16 is connected to the upper end of the reactor 12. The outlet pipe 16 passes through the upper end of the pressure vessel 11. The outlet pipe 16 is a gas flow path for discharging the produced gas to the outside of the reactor 12. The produced gas is a gas produced inside the reactor 12, and is a mixed gas of hydrogen produced by thermal decomposition and unreacted hydrocarbons.

[0012] The raw material gas is supplied to the reaction chamber 12A via the airflow chamber 12B and the disperser 13. The raw material gas is rectified and diffused by the disperser 13. This allows the raw material gas to flow uniformly into the reaction chamber 12A from below. When the raw material gas is blown into the reaction chamber 12A from below, the catalyst 14, which is a solid particle, is suspended to a certain height and moves around vigorously. In other words, a fluidized bed, which is a layer of catalyst 14 that moves around vigorously, is formed. The fluidization of the catalyst 14 results in a good mixture of the catalyst 14 and the raw material gas. This promotes contact between the raw material gas and the catalyst 14. Therefore, the thermal decomposition reaction of the raw material gas by the catalyst 14 is promoted.

[0013] The reactor 12 is a fluidized bed reaction vessel. The catalyst 14 is a fluidizing medium. The raw material gas is a fluidizing gas for fluidizing the catalyst 14. <Reaction Temperature> When hydrogen is produced, the inside of the reactor 12, and therefore the catalyst 14, is heated to a predetermined reaction temperature. The reaction temperature is a temperature at which the thermal decomposition reaction of the raw material gas by the catalyst 14 proceeds efficiently. The reaction temperature is set to a value within a predetermined temperature range depending on product specifications, etc. The lower limit of the temperature range is set, for example, based on the starting temperature of thermal decomposition. The upper limit of the temperature range is set, for example, based on the heat resistance of the reactor 12.

[0014] If the reaction temperature is below the lower limit of the temperature range, the thermal decomposition reaction of the raw material gas may not proceed. This is because the reaction temperature is lower than the starting temperature of thermal decomposition, and the function of the catalyst 14 to decompose the raw material gas is not activated. The higher the reaction temperature, the more the thermal decomposition of the raw material gas proceeds. However, if the reaction temperature exceeds the upper limit of the temperature range, the reliability of the reactor 12 may not be ensured.

[0015] <Relationship Between Pressure in Reactor 12 and Amount of Hydrogen Generated> Next, the relationship between the pressure in the reactor 12 and the amount of hydrogen generated will be described. The pressure is the pressure inside the reactor 12. The pressure inside the reactor 12 is a pressure that corresponds to the pressure of the raw material gas supplied into the reactor 12. Here, the case where the raw material gas is methane will be described as an example.

[0016] The thermal decomposition reaction of methane is represented by the following formula (1): CH４ →2H ２ +C (1) Furthermore, when the methane thermal decomposition is in a reaction equilibrium state, the following formula (2) holds regardless of the pressure in the reactor 12.

[0017] P Ｈ２ ２ / P ＣＨ４ = constant ... (2) However, "P Ｈ２ ２ " is the partial pressure of hydrogen inside the reactor 12, and is a pressure that depends on the amount of hydrogen generated. ＣＨ４ " is the partial pressure of methane inside the reactor 12, which is a pressure that depends on the pressure of the methane fed to the reactor 12. " / " indicates division.

[0018] If the pressure in the reactor 12, i.e., the methane supply pressure, is increased fourfold, it would appear at first glance that the methane partial pressure and the hydrogen partial pressure would also increase fourfold. However, according to equation (2), the hydrogen partial pressure would actually double. In other words, the amount of hydrogen generated would be halved compared to before the pressure increase.

[0019] In this way, when the pressure in the reactor 12, i.e., the methane supply pressure, is increased, the amount of hydrogen generated in the reaction equilibrium becomes less than before the pressure was increased. In other words, the methane conversion rate decreases. The conversion rate is the degree of the thermal decomposition reaction in the reactor 12 and indicates the rate of conversion of the raw material gas, methane, to hydrogen. The pressure in the reactor 12, i.e., the methane supply pressure, is set according to product specifications, etc.

[0020] <Regarding supply and discharge of catalyst 14> During operation of the hydrogen production device 10, the activity of the catalyst 14 gradually decreases as the thermal decomposition reaction progresses. Therefore, in order to maintain the decomposition rate of the raw material gas, it is necessary to supply new catalyst 14 to the reactor 12 and remove catalyst 14 with reduced activity from the reactor 12. Catalyst 14 with reduced activity includes deactivated catalyst 14. Deactivation occurs when the catalyst 14 loses its activity and no longer causes the thermal decomposition reaction of the raw material gas. The decomposition rate is the rate at which the raw material gas is decomposed over a certain period of time by the action of the catalyst 14.

[0021] The catalyst 14 with reduced activity has smaller particle size and density than new catalyst 14. The reduced particle size and particle density of the catalyst 14 cause the terminal velocity to be equal to or less than the superficial velocity. Therefore, the catalyst 14 with reduced activity is basically discharged from the reactor 12 to the outside of the reactor 12 via the discharge pipe 16 together with the product gas. The superficial velocity is the flow velocity of the feed gas calculated assuming that the catalyst 14, which is a packed particle, is not present in the reactor 12. The terminal velocity is the velocity at which the drag force of the feed gas, which applies an upward force to the particles, and the gravity, which applies a downward force to the particles, are balanced.

[0022] However, some of the catalyst 14 with reduced activity binds with carbon generated by thermal decomposition of the raw material gas and remains inside the reactor 12. This is because the particle size or particle density of the catalyst 14 with reduced activity increases as a result of binding with the generated carbon. For this reason, it is necessary to discharge the catalyst 14 with reduced activity to the outside of the reactor 12. Therefore, in this embodiment, the following configuration is adopted as the hydrogen production device 10.

[0023] 1 , the hydrogen production apparatus 10 has a first supply device 21 for supplying new catalyst 14 to the reactor 12. The first supply device 21 is, for example, a lock hopper system. The first supply device 21 is provided on a first supply path 22A. The first supply path 22A is a path for supplying new catalyst 14 to the reactor 12 and is formed, for example, by piping. The first supply path 22A passes through the lower end of the pressure vessel 11 and is connected to the lower end of the reactor 12.

[0024] The first supply device 21 has a first receiving hopper 23, a first intermediate hopper 24, and a first supply hopper 25. The first supply hopper 25, the first intermediate hopper 24, and the first receiving hopper 23 are arranged in this order from the side closest to the reactor 12. The first intermediate hopper 24 is located between the first receiving hopper 23 and the first supply hopper 25. The hoppers are devices for temporarily storing new catalyst 14.

[0025] The first receiving hopper 23 receives new catalyst 14 supplied from the outside and temporarily stores the received new catalyst 14. The pressure in the first receiving hopper 23 is maintained at atmospheric pressure, for example.

[0026] A pressure adjustment pipe is connected to the first intermediate hopper 24 via a valve. By introducing high-pressure gas into the first intermediate hopper 24 via the pipe, it is possible to increase the pressure inside the first intermediate hopper 24 to a pressure higher than atmospheric pressure. Furthermore, by releasing the pressure inside the first intermediate hopper 24 via the pipe, it is possible to reduce the pressure inside the first intermediate hopper 24 to atmospheric pressure. The high-pressure gas is an inert gas such as nitrogen or argon.

[0027] The pressure in the first supply hopper 25 is always maintained higher than the pressure in the reactor 12. This is to suppress backflow of the catalyst 14, for example. A first gate valve 26 is provided in the first supply path 22A between the first receiving hopper 23 and the first intermediate hopper 24. The first gate valve 26 opens and closes the first supply path 22A between the first receiving hopper 23 and the first intermediate hopper 24.

[0028] A second gate valve 27 is provided in the first supply path 22A between the first intermediate hopper 24 and the first supply hopper 25. The second gate valve 27 opens and closes the first supply path 22A between the first intermediate hopper 24 and the first supply hopper 25.

[0029] A third gate valve 28 and a first electric valve 29 are provided on the first supply path 22A between the first supply hopper 25 and the reactor 12. The third gate valve 28 is provided on the first supply path 22A between the first supply hopper 25 and the first electric valve 29. The third gate valve 28 opens and closes the first supply path 22A between the first supply hopper 25 and the first electric valve 29.

[0030] The first electric valve 29 is, for example, a rotary valve. The first electric valve 29 has a motor and a rotor that is rotated by the motor. By controlling the rotation speed of the rotor, it is possible to control the amount of catalyst 14, which is a fine solid particle, discharged.

[0031] A second supply path 22B is connected to the first supply path 22A between the first motor-operated valve 29 and the reactor 12. The second supply path 22B is a path for supplying a carrier gas to the first supply path 22A between the first supply hopper 25 and the reactor 12, and is formed, for example, by piping. The carrier gas is a gas for transporting the catalyst 14 in the first supply path 22A between the first motor-operated valve 29 and the reactor 12 into the reactor 12, and is, for example, an inert gas such as nitrogen or argon. The catalyst 14 moves with the flow of the carrier gas.

[0032] 1 , the hydrogen production apparatus 10 has an extraction device 31 for extracting the catalyst 14 with reduced activity from the reactor 12. The extraction device 31 is provided in an extraction path 32 for the catalyst 14. The extraction path 32 is a path for extracting the catalyst 14 with reduced activity to the outside of the reactor 12, and is formed, for example, by piping. A first end of the extraction path 32 is connected to a portion of the reactor 12 that corresponds to an upper portion of the fluidized bed of the catalyst 14. The upper portion is a portion of the fluidized bed that is farther from the distributor 13 in the axial direction of the reactor 12.

[0033] The discharge device 31 has a cooler 33, a second electric valve 34, and a discharge hopper 35. The cooler 33, the second electric valve 34, and the discharge hopper 35 are arranged in this order from the side closest to the reactor 12. The second electric valve 34 is located between the cooler 33 and the discharge hopper 35. The discharge hopper 35 is connected to a second end of the discharge path 32. The second end is an end of the discharge path 32 opposite to the first end.

[0034] The cooler 33 cools the catalyst 14 with reduced activity that is extracted from the reactor 12. The second electric valve 34 is, for example, a rotary valve. The second electric valve 34 has a motor and a rotor that is rotated by the motor. By controlling the rotation speed of the rotor, it is possible to control the amount of catalyst 14, which is a fine solid particle, that is discharged. The extraction hopper 35 continuously extracts the catalyst 14 with reduced activity and temporarily stores the extracted catalyst 14.

[0035] <Regarding fusion of catalyst 14> The catalyst 14 is, for example, iron or fine solid particles containing iron as a main component. Therefore, if only the catalyst 14 is contained in the reactor 12, the following concerns arise. That is, when the hydrogen production device 10 is started up, the catalyst 14 may fuse together as the temperature of the reactor 12 rises, which may impede the flow of the catalyst 14. Furthermore, during operation of the hydrogen production device 10, the physical properties of the catalyst 14 may gradually change as the thermal decomposition reaction progresses, which may change the stability of the flow of the catalyst 14. The physical properties of the catalyst 14 include the particle size and density of the catalyst 14.

[0036] Therefore, in this embodiment, the hydrogen production device 10 has the following configuration. That is, as shown in Fig. 1, a fluidizing material 17 is mixed with the catalyst 14. The fluidizing material 17 is used to increase the fluidity of the catalyst 14. The fluidizing material 17 is made of fine solid particles, such as inert particles of silicon.

[0037] 1 , the hydrogen production apparatus 10 has a second supply device 41 for supplying the fluid material 17 to the reactor 12. The second supply device 41 is provided on a third supply path 42A. The third supply path 42A is a path for supplying the fluid material 17 to the reactor 12 and is formed, for example, by piping. The third supply path 42A passes through the lower end of the pressure vessel 11 and is connected to the lower end of the reactor 12.

[0038] The second supply device 41 is, for example, a lock hopper system and has a configuration similar to that of the first supply device 21. That is, the second supply device 41 has a second receiving hopper 43, a second intermediate hopper 44, and a second supply hopper 45. The second supply hopper 45, the second intermediate hopper 44, and the second receiving hopper 43 are arranged in this order from the side closest to the reactor 12. The second intermediate hopper 44 is located between the second receiving hopper 43 and the second supply hopper 45.

[0039] The second receiving hopper 43 receives the flowable material 17 supplied from the outside and temporarily stores the received flowable material 17. The pressure in the second receiving hopper 43 is maintained at atmospheric pressure, for example.

[0040] A pressure adjustment pipe is connected to the second intermediate hopper 44 via a valve. By introducing high-pressure gas into the second intermediate hopper 44 via the pipe, it is possible to increase the pressure inside the second intermediate hopper 44 to a pressure higher than atmospheric pressure. Furthermore, by releasing the pressure inside the second intermediate hopper 44 via the pipe, it is possible to reduce the pressure inside the second intermediate hopper 44 to atmospheric pressure. The high-pressure gas is an inert gas such as nitrogen or argon.

[0041] The pressure in the second supply hopper 45 is always maintained higher than the pressure in the reactor 12. This is to suppress backflow of the flowable material 17, for example. A fourth gate valve 46 is provided in the third supply path 42A between the second receiving hopper 43 and the second intermediate hopper 44. The fourth gate valve 46 opens and closes the third supply path 42A between the second receiving hopper 43 and the second intermediate hopper 44.

[0042] A fifth gate valve 47 is provided in the third supply path 42A between the second intermediate hopper 44 and the second supply hopper 45. The fifth gate valve 47 opens and closes the third supply path 42A between the second intermediate hopper 44 and the second supply hopper 45.

[0043] A sixth gate valve 48 and a third electric valve 49 are provided on the third supply path 42A between the second supply hopper 45 and the reactor 12. The sixth gate valve 48 is provided on the third supply path 42A between the second supply hopper 45 and the third electric valve 49. The sixth gate valve 48 opens and closes the third supply path 42A between the second supply hopper 45 and the third electric valve 49.

[0044] The third electric valve 49 is, for example, a rotary valve. The third electric valve 49 has a motor and a rotor that is rotated by the motor. By controlling the rotation speed of the rotor, it is possible to control the amount of catalyst 14, which is a fine solid particle, discharged.

[0045] A fourth supply line 42B branching from the second supply line 22B is connected to a third supply line 42A between the third motor-operated valve 49 and the reactor 12. The fourth supply line 42B is a line for supplying a carrier gas to the third supply line 42A between the third motor-operated valve 49 and the reactor 12, and is formed, for example, by piping. The carrier gas is a gas for transporting the fluidizing material 17 in the third supply line 42A between the third motor-operated valve 49 and the reactor 12 into the reactor 12, and is, for example, an inert gas such as nitrogen or argon. The fluidizing material 17 moves with the flow of the carrier gas.

[0046] <Electrical Configuration of the Hydrogen Production Device 10> Next, a description will be given of the electrical configuration of the hydrogen production device 10. As shown in Fig. 2, the hydrogen production device 10 has a first temperature sensor 51, a second temperature sensor 52, a differential pressure sensor 53, a concentration sensor 54, and a control device 55.

[0047] The first temperature sensor 51 is provided in the reactor 12. The first temperature sensor 51 detects a first temperature T1 of the fluidized bed of the catalyst 14. The first temperature T1 is the temperature of the upper part of the fluidized bed.

[0048] The second temperature sensor 52 is provided in the reactor 12. The second temperature sensor 52 detects a second temperature T2 of the fluidized bed of the catalyst 14. The second temperature T2 is the temperature of the lower part of the fluidized bed.

[0049] The differential pressure sensor 53 is provided in the reactor 12. The differential pressure sensor 53 detects the pressure difference ΔP between the upper part of the reaction chamber 12A and the lower part of the reaction chamber 12A. The upper part of the reaction chamber 12A is an empty part of the reactor 12 that is outside the fluidized bed of the catalyst 14. The lower part of the reaction chamber 12A is a part of the reactor 12 that corresponds to the fluidized bed of the catalyst 14, for example, a part that corresponds directly above the disperser 13.

[0050] The concentration sensor 54 is provided in the outlet pipe 16. The concentration sensor 54 detects the concentration M of hydrogen in the product gas generated by thermal decomposition of the raw material gas. The control device 55 has a processing circuit including any one of the following three configurations A1, A2, and A3.

[0051] A1. One or more processors that operate according to a computer program, which is software. A processor includes a CPU (central processing unit) and memory. A2. One or more dedicated hardware circuits, such as an application specific integrated circuit (ASIC), that perform at least some of the various processes. An ASIC includes a CPU and memory.

[0052] A3. A hardware circuit that combines configurations A1 and A2. The memory is a medium that can be read by a computer (here, the CPU) and stores a program that describes processes or instructions for the computer. The memory includes RAM (random access memory) and ROM (read only memory). The CPU performs various controls by executing the program stored in the memory at a set calculation cycle.

[0053] The control device 55 controls the operations of the first supply device 21, the withdrawal device 31, and the second supply device 41. The control device 55 controls the supply of new catalyst 14 to the reactor 12 through the first supply device 21, for example, based on the detection results of the various sensors (51 to 54). The control device 55 controls the withdrawal of catalyst 14 with reduced activity from the reactor 12 through the withdrawal device 31, for example, based on the detection results of the various sensors (51 to 54). The control device 55 controls the supply of flowable material 17 to the reactor 12 through the second supply device 41.

[0054] <Catalyst 14 Supply Process> When supplying catalyst 14 to reactor 12, the control device 55 controls the first supply device 21 as follows. That is, the control device 55 first opens the first gate valve 26. As a result, new catalyst 14 stored in the first receiving hopper 23 moves by gravity to the first intermediate hopper 24. After moving a predetermined amount of catalyst 14, the control device 55 closes the first gate valve 26.

[0055] Next, the control device 55 introduces high-pressure gas into the first intermediate hopper 24 through the pressure adjustment piping. As a result, the pressure inside the first intermediate hopper 24 is increased to the same level as the pressure in the first supply hopper 25. The pressure in the first supply hopper 25 is maintained at a pressure equal to or higher than the pressure in the reactor 12. Thereafter, the control device 55 opens the second gate valve 27. As a result, the catalyst 14 in the first intermediate hopper 24 is discharged into the first supply hopper 25.

[0056] After the control device 55 has completed dispensing of the catalyst 14 to the first supply hopper 25, it closes the second gate valve 27 and releases the gas in the first intermediate hopper 24 through a pressure adjustment pipe, thereby reducing the pressure inside the first intermediate hopper 24 to atmospheric pressure. This enables the first intermediate hopper 24 to receive catalyst 14 from the first receiving hopper 23 again.

[0057] Next, the control device 55 opens the third gate valve 28. As a result, the catalyst 14 in the first supply hopper 25 is dispensed to the first electric valve 29. The control device 55 controls the first electric valve 29 so that a fixed amount of catalyst 14 is continuously delivered from the first electric valve 29. The catalyst 14 delivered from the first electric valve 29 is supplied to the reactor 12 by air current transport. That is, the catalyst 14 delivered from the first electric valve 29 merges with the carrier gas at the connection portion between the first supply path 22A and the second supply path 22B and is supplied to the reactor 12 together with the carrier gas. The control device 55 opens the first gate valve 26 while the catalyst 14 is being supplied to the reactor 12. The first intermediate hopper 24 again receives the catalyst 14 from the first receiving hopper 23.

[0058] When the amount of catalyst 14 in the first supply hopper 25 decreases to near the lower limit, the control device 55 closes the first gate valve 26 and introduces high-pressure gas into the first intermediate hopper 24 through a pressure adjustment pipe. This increases the pressure inside the first intermediate hopper 24 to the same level as the pressure in the first supply hopper 25. Thereafter, the control device 55 opens the second gate valve 27. This causes the catalyst 14 in the first intermediate hopper 24 to be dispensed into the first supply hopper 25.

[0059] After the control device 55 has completed dispensing of the catalyst 14 to the first supply hopper 25, it closes the second gate valve 27 and releases the gas in the first intermediate hopper 24 through a pressure adjustment pipe, thereby reducing the pressure inside the first intermediate hopper 24 to atmospheric pressure. When the pressure inside the first intermediate hopper 24 becomes approximately the same as atmospheric pressure, i.e., the pressure in the first receiving hopper 23, the control device 55 opens the first gate valve 26. This allows the first intermediate hopper 24 to again receive catalyst 14 from the first receiving hopper 23.

[0060] The control device 55 repeatedly executes the above process to continuously supply the catalyst 14 to the reactor 12. The catalyst 14 is supplied to the reactor 12 by being transported by the carrier gas.

[0061] <Process for withdrawing catalyst 14 from reactor 12> When withdrawing catalyst 14 from reactor 12, the control device 55 controls the withdrawing device 31 as follows. That is, the control device 55 activates the cooler 33 and the second electric valve 34. As a result, the catalyst 14 with reduced activity is withdrawn from the reactor 12. The withdrawn catalyst 14 is cooled by the cooler 33. The cooled catalyst 14 is sent to the withdrawing hopper 35 by the second electric valve 34.

[0062] The control device 55 may execute the catalyst 14 extraction process and the catalyst 14 supply process at the same timing. In this case, the amount of catalyst 14 discharged may be the same as the amount of catalyst 14 supplied by the first supply device 21, for example. The catalyst 14 discharge rate may be the same as the catalyst 14 supply rate by the first supply device 21. In this way, fluctuations in the height of the catalyst layer are gradual, and it is easier to maintain a uniform catalyst layer. Depending on product specifications, the control device 55 may execute the catalyst 14 extraction process and the catalyst 14 supply process at different timings.

[0063] <Supplying Process of Fluidizing Material 17> When supplying the fluidizing material 17 to the reactor 12, the control device 55 controls the second supply device 41 in the same manner as the first supply device 21. This allows the fluidizing material 17 to be continuously supplied to the reactor 12. The fluidizing material 17 is supplied to the reactor 12 by being air-transported by the carrier gas. The supply amount of the fluidizing material 17 is set to an appropriate amount depending on the product specifications, etc.

[0064] At least at the start-up of the hydrogen production apparatus 10, the control device 55 supplies the fluidizing material 17 into the reactor 12 before performing the activation process of the catalyst 14 housed in the reactor 12. The control device 55 may perform the supply process of the fluidizing material 17 at the same timing as the supply process of the catalyst 14 or the withdrawal process of the catalyst 14, for example. Furthermore, depending on the product specifications, the control device 55 may perform the supply process of the fluidizing material 17 at a different timing from the supply process of the catalyst 14 or the withdrawal process of the catalyst 14. For example, the fluidizing material 17 may be supplied to the reactor 12 after the catalyst 14 has been supplied to the reactor 12 or after the catalyst 14 has been withdrawn from the reactor 12.

[0065] Alternatively, the raw material gas may be used as the carrier gas. In this case, the new catalyst 14 and fluidizing material 17 are supplied to the reactor 12 by the flow of the raw material gas. <Effects of the First Embodiment> The first embodiment has the following effects.

[0066] (1-1) By mixing the fluidizing material 17 with the catalyst 14, it is possible to prevent the catalyst 14 from fusing together inside the reactor 12. This allows the catalyst 14 to flow stably. In addition, it is possible to ensure the stability of the flow of the catalyst 14.

[0067] (1-2) The fluidizing material 17 is supplied to the reactor 12, for example, in response to the supply of new catalyst 14 or the discharge of inactive catalyst 14. Fusion between catalysts 14 is suppressed. (1-3) The pressure in the reactor 12 is higher than atmospheric pressure. The second supply device 41 pressurizes the fluidizing material 17 to a pressure equal to or higher than the pressure in the reactor 12 and continuously transports it by airflow. With this configuration, the fluidizing material 17 can be supplied to the reactor 12 by airflow transport.

[0068] (1-4) The pressure in the reactor 12 is higher than atmospheric pressure. The first supply device 21 pressurizes new catalyst 14 to a pressure equal to or higher than the pressure in the reactor 12 and continuously transports it by pneumatic flow. With this configuration, new catalyst 14 can be supplied to the reactor 12 by pneumatic transport.

[0069] (1-5) The catalyst 14 with reduced activity is discharged from the reactor 12 by the discharge device 31. This prevents carbon generated by thermal decomposition of the raw material gas from binding to the catalyst 14 with reduced activity and remaining inside the reactor 12.

[0070] Second Embodiment Next, a second embodiment of the hydrogen production apparatus will be described. This embodiment differs from the first embodiment in the configuration of the first supply device 21 that supplies new catalyst 14 to the reactor 12. Therefore, the same members and configurations as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0071] The catalyst 14 before activation treatment must be activated through an activation treatment. The activation treatment is, for example, a treatment in which the catalyst 14 before activation is heated at a predetermined activation treatment temperature for a predetermined time. Activation of the catalyst 14 causes a thermal decomposition reaction of the raw material gas. Heating can be performed by bringing a heated gas into contact with the catalyst 14, or by using a burner, as long as the catalyst 14 before activation can be heated. The gas can be, for example, the raw material gas or nitrogen.

[0072] 3, the first supply device 21 includes a rotary kiln 61 and a hopper 62. The hopper 62 and the rotary kiln 61 are arranged in this order from the side closest to the reactor 12. The hopper 62 has a configuration similar to that of the first intermediate hopper 24 or the first supply hopper 25, for example.

[0073] The rotary kiln 61 is an activation device that activates the catalyst 14 while stirring it before activation. The rotary kiln 61 has an inlet 61A, a rotor 61B, and a discharge 61C. The rotor 61B is hollow and cylindrical. The rotor 61B can rotate about its axis when torque from a motor (not shown) is applied, for example. The inlet 61A is connected to a first end of the rotor 61B. The interiors of the inlet 61A and the rotor 61B are in communication with each other. The second end of the rotor 61B is connected to the discharge 61C. The second end is the end of the rotor 61B opposite the first end. The interiors of the rotor 61B and the discharge 61C are in communication with each other. The discharge 61C is connected to the reactor 12 via an inlet pipe 15.

[0074] The rotor 61B is slightly inclined so that the discharge section 61C is lower than the introduction section 61A. The introduction section 61A introduces the raw material gas supplied through a gas flow path (not shown) into the rotor 61B. The raw material gas is a hydrocarbon gas. The introduction section 61A also introduces the catalyst 14 before activation treatment, supplied through a catalyst 14 supply path (not shown), into the rotor 61B. The catalyst 14 introduced into the rotor 61B is heated by a heating device (not shown) while being stirred by the rotation of the rotor 61B. The catalyst 14 is activated by contacting the raw material gas with the raw material gas at a predetermined activation treatment temperature for a predetermined time. As the rotor 61B rotates, the catalyst 14 inside the rotor 61B moves from the first end toward the second end of the rotor 61B and eventually reaches the discharge section 61C. The catalyst 14 in the discharge section 61C is supplied to the reactor 12 via a hopper 62. The raw material gas introduced into the rotor 61B is supplied to the reactor 12 via an inlet pipe 15 .

[0075] This embodiment can be applied to the first embodiment. That is, the discharge unit 61C may be connected to, for example, the first receiving hopper 23 or the first intermediate hopper 24. In this case, the catalyst 14 in the discharge unit 61C is supplied to the first receiving hopper 23 or the first intermediate hopper 24. When the discharge unit 61C is connected to the first intermediate hopper 24, the hydrogen production device 10 may have a configuration in which the first receiving hopper 23 is omitted.

[0076] Furthermore, the rotary kiln 61 does not have to be a part of the first supply device 21. That is, the rotary kiln 61 may be provided independently of the first supply device 21. The reactor 12 only needs to be configured so that the catalyst 14 activated in the rotary kiln 61 is supplied thereto.

[0077] <Effects of the Second Embodiment> The second embodiment has the following effects. (2-1) The catalyst 14 is supplied to the reactor 12 in an already activated state. Because the activated catalyst 14 is supplied to the reactor 12, there is no need to perform an activation process for the catalyst 14 inside the reactor 12. Therefore, for example, when the hydrogen production device 10 is started up, the fusion of the catalyst 14 with the rise in temperature of the reactor 12 is suppressed. Furthermore, the stability of the flow of the catalyst 14 can be ensured.

[0078] (2-2) The catalyst 14 is activated by being heated while being stirred in the rotary kiln 61. This prevents the catalyst 14 from fusing together during the activation process. Therefore, the activated catalyst 14 can be supplied to the reactor 12 in an appropriate state.

[0079] (2-3) Furthermore, by supplying the activated catalyst 14 to the reactor 12, the amount of catalyst 14 retained inside the reactor 12 can be reduced. This is for the following reason. Specifically, the catalyst 14 becomes deactivated after a certain lifespan. It is preferable to discharge the deactivated catalyst 14 from the reactor 12, while retaining the undeactivated catalyst 14 inside the reactor 12. Furthermore, while continuously charging the catalyst 14 into the reactor 12 and continuously discharging the catalyst 14 from the reactor 12, the amount of catalyst 14 inside the reactor 12 should be controlled to a constant amount. For this reason, the amount of catalyst 14 charged into the reactor 12 is similar to the amount of catalyst 14 discharged from the reactor 12. In other words, the amount of catalyst 14 retained inside the reactor 12 is the same whether a small amount of catalyst 14 is charged into the reactor 12 and a small amount of catalyst 14 is discharged from the reactor 12, or whether a large amount of catalyst 14 is charged into the reactor 12 and a large amount of catalyst 14 is discharged from the reactor 12. On the other hand, the time that a specific catalyst 14 remains inside the reactor 12 depends on the amount of catalyst 14 introduced into the reactor 12. For example, if a large amount of catalyst 14 is introduced into the reactor 12 and a large amount of catalyst 14 is discharged from the reactor 12, the time that the catalyst 14 remains inside the reactor 12 will be short. That is, in the case of a catalyst 14 that has not been activated in advance, the time until deactivation, i.e., the life span, will be long, and a large amount of catalyst 14 needs to be maintained inside the reactor 12 to compensate for the longer life span. In this regard, by pretreating the catalyst 14, it is possible to reduce the amount of catalyst 14 packed inside the reactor 12 and make it possible to use up the life span of the catalyst 14. The pretreatment is an activation treatment.

[0080] Other Embodiments Each embodiment may be modified as follows: In the first and second embodiments, the pressure in the reactor 12 may be maintained at atmospheric pressure. In this case, the hydrogen production device 10 may have a configuration in which the pressure vessel 11 is omitted. The lower the pressure in the reactor 12, the higher the methane conversion rate.

[0081] In the first embodiment, as shown by the two-dot chain arrow in FIG. 1 , when the pressure in the reactor 12 and the pressure in the first feed hopper 25 are equal, the catalyst 14 may be supplied to the reactor 12 by gravity. When the pressure in the reactor 12 and the pressure in the second feed hopper 45 are equal, the fluidized material 17 may be supplied to the reactor 12 by gravity. The pressure may be, for example, atmospheric pressure. In this case, the first feed hopper 25 is connected to the upper part of the reactor 12 via, for example, the third gate valve 28 and the first electric valve 29. The second feed hopper 45 is connected to the upper part of the reactor 12 via the sixth gate valve 48 and the third electric valve 49. The same applies to the second embodiment.

[0082] In the first and second embodiments, the catalyst 14 may be metals such as nickel and cobalt, or fine metal particles primarily composed of these metals. As used herein, the terms "cylinder" or "cylindrical" may refer to any structure having a peripheral wall. The terms "cylinder" or "cylindrical" may refer to any structure having a cross-sectional shape, such as, but not limited to, a circle, an ellipse, or a polygon with sharp or rounded corners.

[0083] In this specification, whether a catalyst 14 is new or not does not depend on whether it has been pretreated or not, but on whether it has already contributed to the reaction as a catalyst 14. A new catalyst 14 is a catalyst 14 that has not yet contributed to the reaction.

[0084] <Additional Notes> The hydrogen production device described in this embodiment can be understood, for example, as follows: 1. A hydrogen production device (10) according to a first aspect is a hydrogen production device (10) having a reactor (12) that produces hydrogen by thermally decomposing a hydrocarbon gas, which is a raw material gas, using a catalyst (14) that is fine metal particles, and in which a fluidized bed of the catalyst (14) is formed inside the reactor (12) by introducing the raw material gas from a bottom, and in which a fluidizing material (17), which is inert particles, for increasing the fluidity of the catalyst (14) is mixed with the catalyst (14).

[0085] According to the hydrogen production device of the first aspect, by mixing the fluidizing material with the catalyst, it is possible to prevent the catalyst from fusing together inside the reactor. The hydrogen production apparatus (10) according to the second aspect is the hydrogen production apparatus (10) according to the first aspect, wherein the pressure of the reactor (12) is higher than atmospheric pressure, and the hydrogen production apparatus (10) includes a first supply device (21) configured to supply new catalyst (14) to the reactor (12), an extraction device (31) configured to extract the catalyst (14) with reduced activity from the reactor (12), and a second supply device (41) configured to supply the fluid material (17) to the reactor (12), wherein the first supply device (21) is configured to pressurize the new catalyst (14) to a pressure equal to or higher than the pressure of the reactor (12) and continuously transport it in a gas stream, and the second supply device (41) is configured to pressurize the fluid material (17) to a pressure equal to or higher than the pressure of the reactor (12) and continuously transport it in a gas stream.

[0086] In the hydrogen production apparatus according to the second aspect, the first supply device supplies new catalyst to the reactor by pneumatic transport, and the extractor extracts catalyst with reduced activity from the reactor. Also, the second supply device supplies a fluid material to the reactor by pneumatic transport.

[0087] 3. A hydrogen production apparatus (10) according to a third aspect is the hydrogen production apparatus (10) according to the second aspect, wherein the first supply device (21) has an activating device (61) configured to activate the catalyst (14) before activation by heating it while stirring, and the first supply device (21) is configured to supply the catalyst (14) activated by the activating device (61) to the reactor (12).

[0088] According to the hydrogen production device of the third aspect, an activated catalyst is supplied to the reactor. Therefore, there is no need to perform an activation process for the catalyst inside the reactor. Therefore, for example, when the hydrogen production device is started up, it is possible to prevent the catalyst from fusing together as the temperature of the reactor rises. Furthermore, during the activation process, the catalyst is heated while being stirred. Therefore, it is possible to prevent the catalyst from fusing together during the activation process.

[0089] 4. The hydrogen production device (10) according to a fourth aspect is the hydrogen production device (10) according to the second or third aspect, wherein the carrier gas used for transporting the gas flow is the raw material gas.

[0090] According to the hydrogen production apparatus of the fourth aspect, new catalyst and fluidizing material can be supplied to the reactor by utilizing the flow of the raw material gas. 5. The hydrogen production apparatus (10) of the fifth aspect is configured such that new catalyst (14) and fluidizing material (17) are supplied to the reactor (12) by gravity in the hydrogen production apparatus (10) of the first aspect.

[0091] According to the hydrogen production apparatus of the fifth aspect, a new catalyst and a fluidizing material can be supplied to the reactor by gravity. 6. A hydrogen production apparatus (10) of the sixth aspect includes a first supply device (21) configured to supply the catalyst (14) to the reactor (12) by gravity, an extraction device (31) configured to extract the catalyst (14) with reduced activity from the reactor (12), and a second supply device (41) configured to supply the fluidizing material (17) to the reactor (12) by gravity, wherein the first supply device (21) has an activating device (61) configured to activate the catalyst (14) before activation by heating while stirring, and the first supply device (21) is configured to supply the catalyst (14) activated by the activating device (61) to the reactor (12).

[0092] According to the hydrogen production device of the sixth aspect, an activated catalyst is supplied to the reactor. Therefore, there is no need to perform an activation process for the catalyst inside the reactor. Therefore, for example, when the hydrogen production device is started up, it is possible to prevent the catalyst from fusing together as the temperature of the reactor rises. Furthermore, during the activation process, the catalyst is heated while being stirred. Therefore, it is possible to prevent the catalyst from fusing together during the activation process.

Claims

1. A hydrogen production device having a reactor that produces hydrogen by thermally decomposing a hydrocarbon gas, which is a raw material gas, using a catalyst that is fine metal particles, and in which a fluidized bed of the catalyst is formed inside the reactor by introducing the raw material gas from the bottom, and in which a fluidizing material, which is inert particles, is mixed into the catalyst to increase the fluidity of the catalyst.

2. A hydrogen production apparatus as described in claim 1, comprising: a first supply device configured to supply new catalyst to the reactor, an extraction device configured to extract the catalyst with reduced activity from the reactor, and a second supply device configured to supply the fluid material to the reactor, wherein the pressure of the reactor is higher than atmospheric pressure, the first supply device is configured to pressurize the new catalyst to a pressure equal to or higher than the pressure of the reactor and continuously transport it in a gas flow, and the second supply device is configured to pressurize the fluid material to a pressure equal to or higher than the pressure of the reactor and continuously transport it in a gas flow.

3. The hydrogen production apparatus according to claim 2, wherein the first supply device has an activation device configured to activate the catalyst before activation by heating it while stirring, and the first supply device is configured to supply the catalyst activated by the activation device to the reactor.

4. The hydrogen production device according to claim 2 or 3, wherein the carrier gas used for transporting the gas flow is the raw material gas.

5. The hydrogen production apparatus according to claim 1, wherein the novel catalyst and the fluid material are supplied to the reactor by gravity.

6. A hydrogen production apparatus as described in claim 5, comprising: a first supply device configured to supply the catalyst to the reactor by gravity; an extraction device configured to extract the catalyst with reduced activity from the reactor; and a second supply device configured to supply the flow material to the reactor by gravity, wherein the first supply device has an activation device configured to activate the catalyst before activation by heating while stirring, and the first supply device is configured to supply the catalyst activated by the activation device to the reactor.

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