Hydrogen generation system

Abstract

This technology provides a method for heating ammonia in a reformer with low energy consumption. [Solution] The hydrogen generation system comprises a reformer that generates hydrogen by reforming ammonia, a reactor that generates hydrogen by the ammonia monolith reaction, a combustor that generates high-temperature steam by burning the hydrogen generated in the reactor, and a heater that heats the ammonia in the reformer with the heat of the high-temperature steam generated in the combustor.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a hydrogen generation system.

Background Art

[0002] Patent Document 1 discloses an apparatus including a reformer that generates hydrogen by reforming ammonia, an ammonia supply passage that supplies ammonia to the reformer, a hydrogen supply passage that supplies the hydrogen generated in the reformer to a supply destination (fuel cell), and a heater that heats the ammonia in the reformer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the apparatus of Patent Document 1, since the heater that heats the ammonia in the reformer has an electric or gas configuration, the energy consumption for heating the ammonia in the reformer may increase. This specification provides a technology capable of heating the ammonia in the reformer with less energy consumption.

Means for Solving the Problems

[0005] In a first aspect of the present technology, a hydrogen generation system includes a reformer that generates hydrogen by reforming ammonia, a reactor that generates hydrogen by an ammonolysis reaction of ammonia, a combustor that generates high-temperature steam by burning the hydrogen generated in the reactor, and a heater that heats the ammonia in the reformer with the heat of the high-temperature steam generated in the combustor.

[0006] With this configuration, the hydrogen produced by the ammonolithesis reaction in the reactor can be used to generate high-temperature steam in the combustor. The heat from the high-temperature steam generated in the combustor can then heat the ammonia in the reformer. In this way, by using the ammonolithesis reaction and the combustion of hydrogen to heat the ammonia in the reformer with high-temperature steam, the ammonia in the reformer can be heated with low energy consumption.

[0007] In a second embodiment, the reaction apparatus may comprise a plurality of reactors connected in parallel, in the first embodiment. Each of the plurality of reactors may be capable of producing hydrogen by an ammonolithesis reaction.

[0008] This configuration allows for efficient hydrogen production in the reactor. For example, hydrogen can be continuously produced in multiple reactors. Alternatively, hydrogen can be produced simultaneously in multiple reactors.

[0009] In a third embodiment, in the second embodiment described above, the reactor may be capable of performing, in each of the plurality of reactors, an ammonia supply step in which ammonia is supplied from a source; a hydrogen production step in which hydrogen is produced from the ammonia supplied in the ammonia supply step by an ammonia monolith reaction; and a hydrogen supply step in which the hydrogen produced in the hydrogen production step is supplied to the combustor. With this configuration, hydrogen can be supplied to the combustor by the hydrogen supply step after sufficient hydrogen has been produced in the hydrogen production step.

[0010] In a fourth embodiment, in the third embodiment, the reactor may be further provided with a discharge passage for discharging hydrogen produced in each of the plurality of reactors, and a discharge valve for opening and closing the discharge passage, and the hydrogen production process may be performed with the discharge valve closed.

[0011] With this configuration, the ammonolithesis reaction can proceed sufficiently in each reactor during the hydrogen production process, and sufficient hydrogen can be produced.

[0012] In the fifth embodiment, in the third or fourth embodiment, the reactor may repeatedly perform the ammonia supply step, the hydrogen production step, and the hydrogen supply step in each of the plurality of reactors. This configuration allows hydrogen to be repeatedly supplied to the combustor.

[0013] In the sixth embodiment, in any one of the third to fifth embodiments, the reactor may perform the hydrogen supply process in one of the reactors and the hydrogen supply process in any of the other reactors at different timings. This configuration allows for a continuous supply of hydrogen to the combustor.

[0014] In the seventh embodiment, in the sixth embodiment, the reactor may start the hydrogen supply process in any of the reactors while the hydrogen supply process is being performed in any of the reactors. This configuration allows for an uninterrupted supply of hydrogen to the combustor.

[0015] In the eighth aspect, in any one of the third to seventh aspects described above, the reactor includes a pressure sensor for detecting the gas pressure in at least one of the plurality of reactors, and when the hydrogen supply process is being performed in the at least one reactor, the hydrogen supply process being performed may be terminated based on the pressure detected by the pressure sensor.

[0016] In the reactor, the gas pressure in the reactor decreases as the hydrogen produced in the reactor is supplied to the combustor. With the above configuration, the hydrogen supply process can be terminated depending on the progress of hydrogen supply from the reactor to the combustor.

[0017] In the ninth embodiment, in the eighth embodiment, the reactor may terminate the hydrogen supply process being performed when the time derivative of the pressure detected by the pressure sensor falls below a predetermined threshold. With this configuration, the hydrogen supply process can be terminated at the timing when sufficient hydrogen produced in the reactor has been supplied from the reactor to the combustor.

[0018] In the tenth embodiment, in any one of the third to ninth embodiments, the reactor may perform the ammonia supply process in any of the reactors while the hydrogen supply process is being performed in any of the reactors.

[0019] With this configuration, while hydrogen is being supplied from one of the reactors to the combustor, ammonia can be supplied to any of the other reactors, thus allowing preparation for hydrogen production to be made in any of the other reactors.

[0020] In the eleventh embodiment, in any one of the third to tenth embodiments described above, the reactor is equipped with a concentration sensor for detecting the ammonia concentration in at least one of the plurality of reactors, and when the hydrogen supply step and the ammonia supply step are being performed together in the at least one reactor, the hydrogen supply step being performed may be terminated based on the concentration detected by the concentration sensor.

[0021] In a reactor where both a hydrogen supply process and an ammonia supply process are carried out simultaneously, as hydrogen produced in the reactor is supplied to the combustor, ammonia is supplied to the reactor, causing the ammonia concentration in the reactor to increase. With the above configuration, the hydrogen supply process can be terminated according to the progress of ammonia supply to the reactor. In addition, the hydrogen supply process can be terminated according to the progress of hydrogen supply from the reactor to the combustor.

[0022] In the 12th aspect, in the 11th aspect described above, when the time derivative value of the detected concentration by the concentration sensor becomes less than a predetermined threshold, the hydrogen supply process being executed may be terminated.

[0023] According to this configuration, the hydrogen supply process can be terminated at the timing when ammonia is sufficiently supplied to the reactor. In addition, the hydrogen supply process can be terminated at the timing when the hydrogen generated in the reactor is sufficiently supplied from the reactor to the combustor.

Brief Description of the Drawings

[0024] [Figure 1] The figure schematically shows the hydrogen generation system of the embodiment. [Figure 2] The figure schematically shows the reactor of the embodiment. [Figure 3] The table shows the opening and closing states of the supply valve and the discharge valve in the reactor of the embodiment. [Figure 4] The figure shows the execution timing of the hydrogen supply operation of the embodiment. [Figure 5] The figure shows the execution timing of the hydrogen supply operation of the modified example. [Figure 6] The figure shows the execution timing of the hydrogen supply operation of the modified example. [Figure 7] The figure schematically shows the reactor of the modified example. [Figure 8] The figure schematically shows the reactor of the modified example.

Modes for Carrying Out the Invention

[0025] The hydrogen generation system 2 of the embodiment will be described with reference to the drawings. As shown in FIG. 1, the hydrogen generation system 2 of the embodiment includes an ammonia tank 4, a reformer 8, a first adsorber 18, a reactor 10, a second adsorber 20, a combustor 12, a heater 16, a fuel cell 22, and a control device 100. The hydrogen generation system 2 is a system that generates hydrogen by the reformer 8 and supplies the generated hydrogen to the fuel cell 22.

[0026] The elements of the hydrogen generation system 2 will now be explained. The ammonia tank 4 (an example of an ammonia supply source) stores ammonia gas as a raw material. The ammonia tank 4 is connected to the first ammonia supply channel 30 through which ammonia gas flows. The upstream end of the first ammonia supply channel 30 is connected to the ammonia tank 4, and the downstream end is connected to the reformer 8. The first ammonia supply channel 30 supplies ammonia gas from the ammonia tank 4 to the reformer 8.

[0027] The first ammonia supply passage 30 is equipped with an on-off valve 31 for opening and closing the first ammonia supply passage 30. The first ammonia supply passage 30 is also equipped with a first flow control valve 68 for controlling the flow rate of ammonia gas flowing through the first ammonia supply passage 30. The first flow control valve 68 is located in the first ammonia supply passage 30 downstream of the on-off valve 31. When the on-off valve 31 and the first flow control valve 68 are open, ammonia gas is supplied from the ammonia tank 4 to the reformer 8 through the first ammonia supply passage 30. The ammonia gas in the first ammonia supply passage 30 flows downstream due to the pressure of the ammonia gas stored in the ammonia tank 4 and is supplied to the reformer 8.

[0028] The reformer 8 produces a first fuel gas by reforming the ammonia gas supplied by the first ammonia supply line 30. The configuration of the reformer 8 is not particularly limited. For example, the reformer 8 comprises a container and one or more catalysts placed inside the container. Examples of catalysts used for reforming ammonia gas include copper, nickel, and ruthenium. The first fuel gas produced in the reformer 8 contains hydrogen produced by the reforming of ammonia. The first fuel gas also contains undecomposed ammonia. The ratio of hydrogen to ammonia in the first fuel gas varies depending on the progress of the reforming in the reformer 8.

[0029] The reformer 8 is equipped with a temperature sensor 80 for detecting the temperature of the ammonia gas in the reformer 8. The reformer 8 is also connected to a first fuel gas supply line 34 through which the first fuel gas flows. The upstream end of the first fuel gas supply line 34 is connected to the reformer 8, and the downstream end is connected to the first adsorbent 18. The first fuel gas supply line 34 supplies the first fuel gas from the reformer 8 to the first adsorbent 18.

[0030] The first adsorbent 18 removes ammonia from the first fuel gas supplied through the first fuel gas supply line 34 by adsorbing the ammonia contained in the first fuel gas with an adsorbent. This reduces the concentration of ammonia in the first fuel gas. The configuration of the first adsorbent 18 is not particularly limited. The first adsorbent 18 comprises, for example, a container and one or more adsorbents placed inside the container. Examples of adsorbents used for ammonia adsorption include activated carbon, zeolite, MOF (Metal Organic Framework), etc.

[0031] The first adsorbent 18 is connected to a second fuel gas supply channel 36 through which the first fuel gas, from which ammonia has been adsorbed and removed, flows. The upstream end of the second fuel gas supply channel 36 is connected to the first adsorbent 18, and the downstream end is connected to the fuel cell 22. The second fuel gas supply channel 36 supplies the first fuel gas from the first adsorbent 18 to the fuel cell 22. The first fuel gas supplied to the fuel cell 22 contains hydrogen.

[0032] In addition to the second fuel gas supply passage 36, the fuel cell 22 is connected to an air supply passage 38 through which oxygen-containing air flows. The upstream end of the air supply passage 38 is connected to an air supply source (not shown), and the downstream end is connected to the fuel cell 22. The air supply passage 38 supplies air from the air supply source to the fuel cell 22. The upstream end of the air supply passage 38 may be open to the outside air.

[0033] The fuel cell 22 generates electricity using hydrogen contained in the first fuel gas supplied by the second fuel gas supply line 36 and oxygen contained in the air supplied by the air supply line 38. The configuration of the fuel cell 22 is not particularly limited. For example, the fuel cell 22 comprises a container and a plurality of battery cells (not shown) stacked inside the container, and each battery cell generates electricity through a chemical reaction between hydrogen contained in the first fuel gas and oxygen contained in the air. Each battery cell is, for example, a solid oxide fuel cell (SOFC) or a polymer electrolyte fuel cell (PEFC), but is not limited to these. Note that the configuration of the fuel cell 22 is already known, so a detailed explanation will be omitted.

[0034] Other elements of the hydrogen production system 2 will now be described. A second ammonia supply channel 32, through which ammonia gas flows, is connected to the first ammonia supply channel 30, which is downstream of the on-off valve 31 and upstream of the first flow control valve 68. The upstream end of the second ammonia supply channel 32 is connected to the first ammonia supply channel 30, and the downstream end is connected to the reactor 10. The second ammonia supply channel 32 branches off from the first ammonia supply channel 30 and extends to the reactor 10. The second ammonia supply channel 32 supplies ammonia gas from the first ammonia supply channel 30 to the reactor 10.

[0035] The second ammonia supply channel 32 is equipped with a second flow control valve 70 that controls the flow rate of ammonia gas flowing through the second ammonia supply channel 32. When the on-off valve 31 and the second flow control valve 70 are open, ammonia gas is supplied from the ammonia tank 4 to the reactor 10 through the first ammonia supply channel 30 and the second ammonia supply channel 32. The ammonia gas in the second ammonia supply channel 32 flows downstream due to the pressure of the ammonia gas stored in the ammonia tank 4 and is supplied to the reactor 10.

[0036] Reactor 10 is a device that generates a second fuel gas by decomposing ammonia gas supplied through the second ammonia supply channel 32. More specifically, reactor 10 generates hydrogen through the ammonia ammonia ammonia ammonia ammonia ammonia ammonia ammonia ammonia ammonia ammonia ammonia. The ammonia ammonia ammonia ammonia is a metal alkali hydride ammonia that reacts with an alkali metal hydride to produce hydrogen, as shown in chemical formula (1) below. Examples of alkali metal hydrides include lithium hydride, sodium hydride, potassium hydride, etc. NH3 + LiH ⇔ LiNH2 + H2···(1)

[0037] The second fuel gas produced in reactor 10 contains hydrogen generated by the ammonolithesis reaction. The second fuel gas also contains undecomposed ammonia. The ratio of hydrogen to ammonia in the second fuel gas varies depending on the progress of the ammonolithesis reaction in reactor 10. The ammonolithesis reaction proceeds even at room temperature. Furthermore, the ammonolithesis reaction is an exothermic and reversible reaction.

[0038] The reactor 10 is connected to a third fuel gas supply channel 40 through which the second fuel gas flows. The upstream end of the third fuel gas supply channel 40 is connected to the reactor 10, and the downstream end is connected to the second adsorber 20. The third fuel gas supply channel 40 supplies the second fuel gas from the reactor 10 to the second adsorber 20.

[0039] The second adsorbent 20 removes ammonia from the second fuel gas supplied through the third fuel gas supply line 40 by adsorbing the ammonia contained in the second fuel gas with an adsorbent. This reduces the concentration of ammonia in the second fuel gas. The configuration of the second adsorbent 20 is not particularly limited. The second adsorbent 20 comprises, for example, a container and one or more adsorbents placed inside the container. Examples of adsorbents used for ammonia adsorption include activated carbon, zeolite, MOF (Metal Organic Framework), etc.

[0040] The second adsorbent 20 is connected to a fourth fuel gas supply channel 42 through which the second fuel gas, from which ammonia has been adsorbed and removed, flows. The upstream end of the fourth fuel gas supply channel 42 is connected to the second adsorbent 20, and the downstream end is connected to the combustor 12. The fourth fuel gas supply channel 42 supplies the second fuel gas from the second adsorbent 20 to the combustor 12. The second fuel gas supplied to the combustor 12 contains hydrogen.

[0041] The combustor 12 generates combustion gas by burning the second fuel gas supplied by the fourth fuel gas supply line 42. The configuration of the combustor 12 is not particularly limited. For example, the combustor 12 comprises a container and one or more catalysts placed inside the container. The catalyst used for the combustion of the second fuel gas is, for example, platinum, palladium, rhodium, etc. The combustion gas produced in the combustor 12 contains high-temperature water vapor produced by the combustion of hydrogen contained in the second fuel gas.

[0042] A combustion gas supply passage 44 is connected to the combustor 12 through which combustion gas flows. The upstream end of the combustion gas supply passage 44 is connected to the combustor 12, and the downstream end is connected to the heater 16. The combustion gas supply passage 44 supplies combustion gas from the combustor 12 to the heater 16. The combustion gas supplied to the heater 16 contains high-temperature water vapor.

[0043] The heater 16 is attached to the reformer 8 and heats the ammonia gas in the reformer 8. The heater 16 can also heat the catalyst in the reformer 8. The heater 16 heats the ammonia gas with the heat of the combustion gas supplied by the combustion gas supply passage 44. The combustion gas supplied to the heater 16 contains high-temperature water vapor. The heater 16 can heat the ammonia gas and catalyst in the reformer 8 with the heat of the high-temperature water vapor contained in the combustion gas.

[0044] The configuration of the heater 16 is not particularly limited. For example, the heater 16 includes a tube located inside the reformer 8, through which combustion gas flows, thereby heating the ammonia gas in the reformer 8. The heating of the ammonia gas in the reformer 8 by the heater 16 promotes the reforming of the ammonia gas in the reformer 8.

[0045] The heater 16 may be configured as a gas flow path through which combustion gas containing high-temperature water vapor flows. In this case, the upstream end of the heater 16 (gas flow path) is connected to the combustion gas supply passage 44, and the downstream end is connected to the combustion gas discharge passage 46. The heater 16 supplies combustion gas from the combustion gas supply passage 44 to the combustion gas discharge passage 46. The heater 16 passes linearly through the inside of the reformer 8 and heats the ammonia gas and catalyst inside the reformer 8. In a modified example, the heater 16 may meander inside the reformer 8. Alternatively, the heater 16 may be configured in a spiral shape inside the reformer 8. The configuration of the heater 16 (gas flow path) is not particularly limited.

[0046] In another modified configuration, the heater 16 may be located outside the reformer 8. For example, the heater 16 may be fixed to the outer surface of the reformer 8's container. In this case, the heater 16 can heat the ammonia gas and catalyst inside the reformer 8 by heating the reformer 8 from the outside. The configuration of the heater 16 is not particularly limited as long as it can heat the ammonia gas inside the reformer 8. The heater 16 may also be another container fixed to the outer surface of the reformer 8's container.

[0047] A combustion gas discharge passage 46 is connected to the heater 16. The upstream end of the combustion gas discharge passage 46 is connected to the heater 16, and the downstream end is connected to the destination for the combustion gas discharge. The combustion gas discharge passage 46 discharges the combustion gas emitted from the heater 16 to the destination (not shown).

[0048] The control device 100 of the hydrogen generation system 2 includes, for example, a CPU, ROM, and RAM, and performs control and processing of each element of the hydrogen generation system 2 based on a predetermined program. The control device 100 also performs control and processing of each element of the reaction apparatus 10, which will be described later.

[0049] Next, the operation of the hydrogen generation system 2 of the embodiment will be described. In the hydrogen generation system 2 of the embodiment, when the on-off valve 31 and the first flow control valve 68 provided in the first ammonia supply passage 30 are opened, ammonia gas is supplied to the reformer 8 through the first ammonia supply passage 30. In the reformer 8, a first fuel gas is produced by reforming the ammonia gas. The first fuel gas produced in the reformer 8 contains hydrogen produced by the reforming of ammonia. The first fuel gas also contains undecomposed ammonia.

[0050] The first fuel gas generated in the reformer 8 is supplied to the first adsorber 18 through the first fuel gas supply line 34. In the first adsorber 18, ammonia contained in the first fuel gas is adsorbed and removed. This reduces the concentration of ammonia in the first fuel gas.

[0051] After ammonia is adsorbed and removed in the first adsorbent 18, the first fuel gas is supplied to the fuel cell 22 through the second fuel gas supply line 36. In the fuel cell 22, electricity is generated by a chemical reaction between the hydrogen contained in the first fuel gas and the oxygen contained in the air.

[0052] Furthermore, in the hydrogen generation system 2 of the embodiment, when the on-off valve 31 and the second flow control valve 70 provided in the first ammonia supply passage 30 are open, ammonia gas is supplied to the reactor 10 through the second ammonia supply passage 32. In the reactor 10, a second fuel gas is generated by the ammonia monolithy reaction of ammonia gas. The second fuel gas generated in the reactor 10 contains hydrogen produced by the ammonia monolithy reaction of ammonia. The second fuel gas also contains undecomposed ammonia.

[0053] The second fuel gas generated in the reactor 10 is supplied to the second adsorbent 20 through the third fuel gas supply passage 40. In the second adsorbent 20, ammonia contained in the second fuel gas is adsorbed and removed. As a result, the concentration of ammonia in the second fuel gas decreases.

[0054] After ammonia is adsorbed and removed in the second adsorbent 20, the second fuel gas is supplied to the combustor 12 through the fourth fuel gas supply passage 42. In the combustor 12, combustion gas is generated by the combustion of the second fuel gas. The combustion gas contains high-temperature water vapor produced by the combustion of hydrogen contained in the second fuel gas.

[0055] The combustion gas (combustion gas containing high-temperature water vapor) generated in the combustor 12 is supplied to the heater 16 through the combustion gas supply passage 44. The heater 16 heats the ammonia gas in the reformer 8 with the heat of the combustion gas supplied through the combustion gas supply passage 44. In other words, the heater 16 heats the ammonia gas in the reformer 8 with the heat of the high-temperature water vapor. The reformer 8 generates the first fuel gas by reforming the heated ammonia gas.

[0056] If the temperature of the reformer 8 is sufficiently high, the heater 16 does not need to be used. In this case, the second flow control valve 70 provided in the second ammonia supply passage 32 may be kept closed. The control device 100 may control the opening degree of the second flow control valve 70 based on the temperature detected by the temperature sensor 80 provided in the reformer 8.

[0057] (Detailed description of the reaction apparatus) Next, the detailed configuration of the reactor 10 in the embodiment will be described. As shown in Figure 2, the reactor 10 comprises a first reactor 50a and a second reactor 50b connected in parallel. The first reactor 50a is connected to a first supply passage 48a and a first discharge passage 49a.

[0058] The first supply channel 48a has its upstream end connected to the second ammonia supply channel 32 and its downstream end connected to the first reactor 50a. The first supply channel 48a supplies ammonia gas from the second ammonia supply channel 32 to the first reactor 50a. The first supply channel 48a is equipped with a first supply valve 90a that opens and closes the first supply channel 48a. When the first supply valve 90a is open, ammonia gas is supplied from the second ammonia supply channel 32 to the first reactor 50a through the first supply channel 48a.

[0059] The first discharge channel 49a has its upstream end connected to the first reactor 50a and its downstream end connected to the third fuel gas supply channel 40. The first discharge channel 49a discharges the second fuel gas from the first reactor 50a to the third fuel gas supply channel 40. The first discharge channel 49a is provided with a first discharge valve 92a that opens and closes the first discharge channel 49a. When the first discharge valve 92a is open, the second fuel gas is discharged from the first reactor 50a to the third fuel gas supply channel 40 through the first discharge channel 49a.

[0060] The first reactor 50a generates a second fuel gas by decomposing the ammonia gas supplied through the first supply channel 48a. More specifically, the first reactor 50a generates hydrogen through the ammonia ammonia ammonia ammonia ammonia ammonia ammonia ammonia ammonia ammonia. The ammonia ammonia ammonia ammonia is a chemical reaction in which hydrogen is produced. Examples of alkali metal hydrides include lithium hydride, sodium hydride, potassium hydride, etc.

[0061] The configuration of the first reactor 50a is not particularly limited. For example, the first reactor 50a comprises a vessel and one or more alkali metal hydrides placed inside the vessel. The second fuel gas produced in the first reactor 50a contains hydrogen produced by the ammonolithesis reaction. The second fuel gas also contains undecomposed ammonia. The ratio of hydrogen to ammonia in the second fuel gas varies depending on the progress of the ammonolithesis reaction in the first reactor 50a. The ammonolithesis reaction proceeds even at room temperature. Furthermore, the ammonolithesis reaction is a reversible reaction.

[0062] The second reactor 50b is connected to the second supply channel 48b and the second discharge channel 49b. The second reactor 50b, the second supply channel 48b, and the second discharge channel 49b have the same configuration as the first reactor 50a, the first supply channel 48a, and the first discharge channel 49a described above, so a detailed explanation is omitted.

[0063] Next, the operation of the reactor 10 will be described. The reactor 10 is capable of performing an ammonia supply process, a hydrogen production process, and a hydrogen supply process in both the first reactor 50a and the second reactor 50b. In the following, the ammonia supply process, hydrogen production process, and hydrogen supply process in the first reactor 50a will be described in detail. The ammonia supply process, hydrogen production process, and hydrogen supply process in the second reactor 50b are the same as those in the first reactor 50a, so detailed explanations may be omitted.

[0064] The ammonia supply process is the process of supplying ammonia gas to the first reactor 50a. As shown in Figure 3, in the ammonia supply process, the reactor 10 opens the first supply valve 90a located in the first supply passage 48a. When the first supply valve 90a is open, ammonia gas is supplied to the first reactor 50a through the first supply passage 48a. Also in the ammonia supply process, the reactor 10 closes the first discharge valve 92a located in the first discharge passage 49a. When the first discharge valve 92a is closed, the first fuel gas is not discharged from the first reactor 50a.

[0065] The hydrogen production process is a process in which hydrogen is produced in the first reactor 50a by an ammonia lysis reaction. In the hydrogen production process, the reactor 10 closes the first supply valve 90a located in the first supply passage 48a. When the first supply valve 90a is closed, ammonia gas is not supplied to the first reactor 50a. Also in the hydrogen production process, the reactor 10 closes the first discharge valve 92a located in the first discharge passage 49a. When the first discharge valve 92a is closed, the first fuel gas is not discharged from the first reactor 50a.

[0066] The hydrogen supply process is a process for supplying hydrogen produced in the first reactor 50a to the combustor 12 (see Figure 1). In the hydrogen supply process, the reactor 10 closes the first supply valve 90a located in the first supply passage 48a. When the first supply valve 90a is closed, ammonia gas is not supplied to the first reactor 50a. Also in the hydrogen supply process, the reactor 10 opens the first discharge valve 92a located in the first discharge passage 49a. When the first discharge valve 92a is open, the first fuel gas is discharged from the first reactor 50a. The first fuel gas discharged from the first reactor 50a is supplied to the combustor 12 through the third fuel gas supply passage 40 and the fourth fuel gas supply passage 42 (see Figure 1).

[0067] The reactor 10 can repeatedly perform the ammonia supply step, the hydrogen production step, and the hydrogen supply step in this order in both the first reactor 50a and the second reactor 50b. The reactor 10 may also perform the above three steps (ammonia supply step, hydrogen production step, and hydrogen supply step) in the first reactor 50a and the above three steps (ammonia supply step, hydrogen production step, and hydrogen supply step) in the second reactor 50b at different timings.

[0068] For example, the reactor 10 may perform the ammonia supply process in the first reactor 50a and the ammonia supply process in the second reactor 50b at different timings. Similarly, the reactor 10 may perform the hydrogen production process in the first reactor 50a and the hydrogen production process in the second reactor 50b at different timings. Similarly, the reactor 10 may perform the hydrogen supply process in the first reactor 50a and the hydrogen supply process in the second reactor 50b at different timings.

[0069] For example, as shown in Figure 4, the reactor 10 does not need to perform the hydrogen supply process in the second reactor 50b while the hydrogen supply process in the first reactor 50a is being performed. Also, the reactor 10 does not need to perform the hydrogen supply process in the first reactor 50a while the hydrogen supply process in the second reactor 50b is being performed.

[0070] In a modified example, as shown in Figure 5, the reactor 10 may start the hydrogen supply process in the second reactor 50b at the same time as it finishes the hydrogen supply process in the first reactor 50a. Alternatively, the reactor 10 may start the hydrogen supply process in the first reactor 50a at the same time as it finishes the hydrogen supply process in the second reactor 50b.

[0071] In another variation, as shown in Figure 6, the reactor 10 may perform the hydrogen supply process in the second reactor 50b while the hydrogen supply process in the first reactor 50a is being performed. More specifically, the reactor 10 may start the hydrogen supply process in the second reactor 50b while the hydrogen supply process in the first reactor 50a is being performed. That is, the reactor 10 may start the hydrogen supply process in the second reactor 50b after starting the hydrogen supply process in the first reactor 50a but before finishing that hydrogen supply process.

[0072] Similarly, the reactor 10 may perform the hydrogen supply process in the first reactor 50a while the hydrogen supply process in the second reactor 50b is being performed. More specifically, the reactor 10 may start the hydrogen supply process in the first reactor 50a while the hydrogen supply process in the second reactor 50b is being performed. That is, the reactor 10 may start the hydrogen supply process in the first reactor 50a after starting the hydrogen supply process in the second reactor 50b but before ending that hydrogen supply process.

[0073] In each of the above examples, the reactor 10 may perform the ammonia supply process and the hydrogen production process in the first reactor 50a and the second reactor 50b, respectively, depending on the timing of the hydrogen supply process.

[0074] Furthermore, while the timing of the hydrogen supply process was explained in each of the above examples, as shown in Figures 4-6, the reactor 10 may also execute the ammonia supply process and the hydrogen production process at the same timing as the hydrogen supply process described above.

[0075] (effect) The hydrogen generation system 2 of the embodiment has been described above. As described above, the hydrogen generation system 2 comprises a reactor 10 that generates hydrogen by the ammonia monolith reaction, a combustor 12 that generates high-temperature steam by burning the hydrogen generated in the reactor 10, and a heater 16 that heats the ammonia in the reformer 8 with the heat of the high-temperature steam generated in the combustor 12.

[0076] With this configuration, the hydrogen produced by the ammonia monolithion reaction in the reactor 10 can be used to generate high-temperature steam in the combustor 12. The heat from the high-temperature steam generated in the combustor 12 can then heat the ammonia in the reformer 8. In this way, by using the ammonia monolithion reaction and the combustion of hydrogen to heat the ammonia in the reformer 8 with high-temperature steam, the ammonia in the reformer 8 can be heated with low energy consumption.

[0077] The reactor 10 comprises multiple reactors 50a and 50b connected in parallel. Each of the reactors 50a and 50b is capable of producing hydrogen through an ammonolithesis reaction. This configuration allows for efficient hydrogen production in the reactor 10. For example, hydrogen can be produced continuously in the multiple reactors 50a and 50b. Alternatively, hydrogen can be produced simultaneously in the multiple reactors 50a and 50b.

[0078] The reactor 10 is capable of performing an ammonia supply step, a hydrogen production step, and a hydrogen supply step in each of the multiple reactors 50a and 50b. With this configuration, after sufficient hydrogen has been produced in the hydrogen production step, hydrogen can be supplied to the combustor 12 in the hydrogen supply step.

[0079] The reactor 10 is equipped with discharge passages 49a and 49b for discharging hydrogen produced in each of the multiple reactors 50a and 50b, and discharge valves 92a and 92b for opening and closing the discharge passages 49a and 49b. The hydrogen production process is carried out with the discharge valves 92a and 92b closed. With this configuration, the ammoniace reaction can proceed sufficiently in each reactor 50a and 50b during the hydrogen production process, and sufficient hydrogen can be produced.

[0080] The reactor 10 may repeatedly perform the ammonia supply step, the hydrogen production step, and the hydrogen supply step in each of the multiple reactors 50a and 50b. With this configuration, hydrogen can be repeatedly supplied to the combustor 12.

[0081] The reactor 10 may perform the hydrogen supply process in the first reactor 50a and the hydrogen supply process in the second reactor 50b at different timings. This configuration allows for a continuous supply of hydrogen to the combustor 12.

[0082] The reactor 10 may start the hydrogen supply process in the second reactor 50b while the hydrogen supply process in the first reactor 50a is running. Similarly, the reactor 10 may start the hydrogen supply process in the first reactor 50a while the hydrogen supply process in the second reactor 50b is running. This configuration allows for a continuous supply of hydrogen to the combustor 12.

[0083] (Correspondence) The third fuel gas supply line 40 and the fourth fuel gas supply line 42 are examples of "hydrogen supply lines." The combustion gas supply line 44 is an example of a "water vapor supply line."

[0084] Although the embodiments have been described above, the configuration of the hydrogen generation system 2 is not limited to the embodiments described above. In the following description, detailed explanations of configurations similar to those described above may be omitted.

[0085] (Variation 1) As shown in Figure 7, the reactor 10 of Modification 1 is equipped with a first pressure sensor 120a located in the first discharge passage 49a. The first pressure sensor 120a is located in the first discharge passage 49a upstream of the first discharge valve 92a. The first pressure sensor 120a detects the gas pressure in the first discharge passage 49a upstream of the first discharge valve 92a. In this way, the first pressure sensor 120a indirectly detects the gas pressure in the first reactor 50a to which the first discharge passage 49a is connected. In other modifications, the first pressure sensor 120a may be located in the first reactor 50a. In this case, the first pressure sensor 120a directly detects the gas pressure in the first reactor 50a.

[0086] In the modified example 1, the reactor 10 controls the opening and closing of the first discharge valve 92a based on the pressure detected by the first pressure sensor 120a. This allows the reactor 10 to control the hydrogen supply process in the first reactor 50a. For example, while the hydrogen supply process in the first reactor 50a is in progress, the reactor 10 terminates the ongoing hydrogen supply process by switching the first discharge valve 92a from an open state to a closed state based on the pressure detected by the first pressure sensor 120a. More specifically, while the hydrogen supply process in the first reactor 50a is in progress, the reactor 10 terminates the ongoing hydrogen supply process by switching the first discharge valve 92a from an open state to a closed state when the time derivative of the pressure detected by the first pressure sensor 120a falls below a predetermined threshold. The predetermined threshold is, for example, a positive value close to 0 (zero).

[0087] In the first modified example, the reactor 10 may start the ammonia supply process in the first reactor 50a at the same time that the hydrogen supply process in the first reactor 50a is completed. That is, the reactor 10 may switch the first supply valve 90a, located in the first supply passage 48a, from a closed state to an open state at the same time that the first discharge valve 92a, located in the first discharge passage 49a, is switched from an open state to a closed state. In another modified example, the reactor 10 may start the ammonia supply process in the first reactor 50a after a predetermined time has elapsed following the completion of the hydrogen supply process in the first reactor 50a.

[0088] The reactor 10 of the modified example 1 further includes a second pressure sensor 120b provided in the second discharge passage 49b. The second pressure sensor 120b detects the gas pressure in the second reactor 50b. Note that the second pressure sensor 120b for the second reactor 50b has the same configuration as the first pressure sensor 120a for the first reactor 50a described above, so a detailed explanation is omitted.

[0089] (effect) As described above, in the modified example 1, when the hydrogen supply process is being performed in the first reactor 50a, the reactor 10 terminates the hydrogen supply process based on the pressure detected by the first pressure sensor 120a.

[0090] In the reactor 10, the gas pressure in the first reactor 50a decreases as hydrogen generated in the first reactor 50a is supplied to the combustor 12. With the above configuration, the hydrogen supply process can be terminated according to the progress of hydrogen supply from the first reactor 50a to the combustor 12. The same applies to the second reactor 50b.

[0091] The reactor 10 may terminate the hydrogen supply process it is performing when the time derivative of the pressure detected by the first pressure sensor 120a falls below a predetermined threshold. With this configuration, the hydrogen supply process can be terminated at the timing when sufficient hydrogen generated in the first reactor 50a has been supplied from the first reactor 50a to the combustor 12. The same applies to the second reactor 50b.

[0092] (Modification 2) As shown in Figure 8, the reactor 10 of Modification 2 is equipped with a first concentration sensor 130a located in the first discharge passage 49a. The first concentration sensor 130a is located in the first discharge passage 49a upstream of the first discharge valve 92a. The first concentration sensor 130a detects the ammonia concentration in the first discharge passage 49a upstream of the first discharge valve 92a. In this way, the first concentration sensor 130a indirectly detects the ammonia concentration in the first reactor 50a to which the first discharge passage 49a is connected. In other modifications, the first concentration sensor 130a may be located in the first reactor 50a. In this case, the first concentration sensor 130a directly detects the ammonia concentration in the first reactor 50a.

[0093] In Modification 2, the reactor 10 also performs the ammonia supply process in the first reactor 50a while the hydrogen supply process in the first reactor 50a is being performed. For example, the reactor 10 starts the hydrogen supply process and the ammonia supply process in the first reactor 50a simultaneously. In another modification, the reactor 10 may start the ammonia supply process while the hydrogen supply process in the first reactor 50a is being performed. In order to perform the ammonia supply process and the hydrogen supply process in the first reactor 50a together, the reactor 10 opens the first discharge valve 92a located in the first discharge passage 49a and also opens the first supply valve 90a located in the first supply passage 48a.

[0094] The reactor 10 can discharge the first fuel gas from the first reactor 50a to the first discharge channel 49a by the pressure of the ammonia gas supplied to the first reactor 50a through the first supply channel 48a, by performing the ammonia supply process simultaneously with the hydrogen supply process in the first reactor 50a. The first fuel gas discharged from the first reactor 50a is then discharged to the third fuel gas supply channel 40 through the first discharge channel 49a.

[0095] In the modified example 2, the reactor 10 controls the opening and closing of the first discharge valve 92a based on the concentration detected by the first concentration sensor 130a. This allows the reactor 10 to control the hydrogen supply process in the first reactor 50a. For example, while the hydrogen supply process and ammonia supply process are running in the first reactor 50a, the reactor 10 terminates the ongoing hydrogen supply process by switching the first discharge valve 92a from an open state to a closed state based on the concentration detected by the first concentration sensor 130a. More specifically, while the hydrogen supply process and ammonia supply process are running in the first reactor 50a, the reactor 10 terminates the ongoing hydrogen supply process by switching the first discharge valve 92a from an open state to a closed state when the time derivative of the concentration detected by the first concentration sensor 130a falls below a predetermined threshold. The predetermined threshold is, for example, a positive value close to 0 (zero).

[0096] In the modified example 2, the reactor 10 may terminate the ammonia supply process, which is currently running, at the same time as it terminates the hydrogen supply process in the first reactor 50a. That is, the reactor 10 may switch the first supply valve 90a, located in the first supply passage 48a, from an open state to a closed state at the same time as it switches the first discharge valve 92a, located in the first discharge passage 49a, from an open state to a closed state. In other modified examples, the reactor 10 may terminate the ammonia supply process in the first reactor 50a after a predetermined time has elapsed following the termination of the hydrogen supply process in the first reactor 50a.

[0097] In other modifications, the reactor 10 may control the opening and closing of the first supply valve 90a based on the concentration detected by the first concentration sensor 130a. More specifically, the reactor 10 may terminate the ammonia supply process in progress by switching the first supply valve 90a from an open state to a closed state when the time derivative of the concentration detected by the first concentration sensor 130a falls below a predetermined threshold during the execution of the hydrogen supply process and the ammonia supply process in the first reactor 50a.

[0098] The reaction apparatus 10 of the modified example 2 further includes a second concentration sensor 130b provided in the second discharge passage 49b. The second concentration sensor 130b detects the concentration of ammonia in the second reactor 50b. Note that the second concentration sensor 130b for the second reactor 50b has the same configuration as the first concentration sensor 130a for the first reactor 50a described above, so a detailed explanation is omitted.

[0099] (effect) As described above, when the reaction apparatus 10 is performing both the hydrogen supply process and the ammonia supply process in the first reactor 50a, it terminates the hydrogen supply process based on the concentration detected by the first concentration sensor 130a.

[0100] In the first reactor 50a, where the hydrogen supply process and the ammonia supply process are carried out simultaneously, as the generated hydrogen is supplied to the combustor 12, ammonia is supplied to the first reactor 50a, causing the ammonia concentration in the first reactor 50a to increase. With the above configuration, the hydrogen supply process can be terminated according to the progress of ammonia supply to the first reactor 50a. In addition, the hydrogen supply process can be terminated according to the progress of hydrogen supply from the first reactor 50a to the combustor 12.

[0101] The reactor 10 may terminate the hydrogen supply process when the time derivative of the concentration detected by the first concentration sensor 130a falls below a predetermined threshold. With this configuration, the hydrogen supply process can be terminated when sufficient ammonia has been supplied to the first reactor 50a. In addition, the hydrogen supply process can be terminated when sufficient hydrogen generated in the first reactor 50a has been supplied from the first reactor 50a to the combustor 12.

[0102] (Other variations) (1) In the above embodiment, the hydrogen generation system 2 supplied hydrogen to the fuel cell 22, but the destination of the hydrogen supply is not particularly limited. In a modified example, the hydrogen generation system 2 may supply hydrogen to another hydrogen consumption device or hydrogen storage device.

[0103] (2) In a modified example, the reactor 10 may perform the above three steps in the first reactor 50a (ammonia supply step, hydrogen production step, and hydrogen supply step) and the above three steps in the second reactor 50b (ammonia supply step, hydrogen production step, and hydrogen supply step) at the same time.

[0104] For example, the reactor 10 may perform the ammonia supply process in the first reactor 50a and the ammonia supply process in the second reactor 50b at the same time. Similarly, the reactor 10 may perform the hydrogen production process in the first reactor 50a and the hydrogen production process in the second reactor 50b at the same time. Similarly, the reactor 10 may perform the hydrogen supply process in the first reactor 50a and the hydrogen supply process in the second reactor 50b at the same time.

[0105] (3) In a modified example, the reactor 10 may perform the ammonia supply process in the second reactor 50b while the hydrogen supply process in the first reactor 50a is being performed. Alternatively, the reactor 10 may perform the ammonia supply process in the first reactor 50a while the hydrogen supply process in the second reactor 50b is being performed.

[0106] With this configuration, while hydrogen is being supplied from the first reactor 50a to the combustor 12, ammonia can be supplied to the second reactor 50b, thus preparing the second reactor 50b for hydrogen production. The reverse is also true.

[0107] (4) In the above-described embodiment, modification 1 and modification 2, the reactor 10 was equipped with a first reactor 50a and a second reactor 50b, but in other modifications, the reactor 10 may be equipped with three or more reactors. In this case, the relationship between any one of the multiple reactors equipped in the reactor 10 and any of the other reactors may be the same as the relationship between the first reactor 50a and the second reactor 50b described above. That is, the multiple (three or more) reactors may be connected in parallel and each may be capable of producing hydrogen by an ammonia monolith reaction. Furthermore, the reactor 10 may be capable of performing an ammonia supply step, a hydrogen production step, and a hydrogen supply step in each of the multiple (three or more) reactors.

[0108] (5) In a modified example, the reactor 10 may perform a preparation step and a startup step. In the preparation step, the reactor 10 performs an ammonia supply step and a hydrogen production step, but does not perform a hydrogen supply step. In the startup step, the reactor 10 performs an ammonia supply step, a hydrogen production step, and a hydrogen supply step.

[0109] (6) In a modified example, the reaction apparatus 10 may be equipped with a heater (not shown) for heating the first reactor 50a. Similarly, the reaction apparatus 10 may be equipped with a heater (not shown) for heating the second reactor 50b.

[0110] (7) In a modified example, the reformer 8, combustor 12, heater 16, and fuel cell 22 may be arranged in an insulated area.

[0111] Although specific examples of the present invention have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples illustrated above. The technical elements described in this specification or drawings exhibit technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technologies illustrated in this specification or drawings can achieve multiple objectives simultaneously, and achieving even one of these objectives itself constitutes technical usefulness. [Explanation of symbols]

[0112] 2: Hydrogen generation system, 4: Ammonia tank, 8: Reformer, 10: Reactor, 12: Combustor, 16: Heater, 18: First adsorber, 20: Second adsorber, 22: Fuel cell, 30: First ammonia supply channel, 31: On / off valve, 32: Second ammonia supply channel, 34: First fuel gas supply channel, 36: Second fuel gas supply channel, 38: Air supply channel, 40: Third fuel gas supply channel, 42: Fourth fuel gas supply channel, 44: Combustion gas supply channel 46: Combustion gas exhaust passage, 48a: First supply passage, 48b: Second supply passage, 49a: First discharge passage, 49b: Second discharge passage, 50a: First reactor, 50b: Second reactor, 68: First flow control valve, 70: Second flow control valve, 80: Temperature sensor, 90a: First supply valve, 92a: First discharge valve, 100: Control device, 120a: First pressure sensor, 120b: Second pressure sensor, 130a: First concentration sensor, 130b: Second concentration sensor

Claims

1. A reformer that produces hydrogen by reforming ammonia, A first ammonia supply path for supplying ammonia to the reformer, A reactor that produces hydrogen by the ammonia ammonia monolysis reaction, A second ammonia supply channel for supplying ammonia to the reactor, A combustor that generates high-temperature steam by burning hydrogen, A hydrogen supply path for supplying hydrogen produced in the reactor to the combustor, A heater that heats the ammonia in the reformer by the heat of steam, A hydrogen generation system comprising a steam supply path for supplying high-temperature steam generated in the combustor to the heater.

2. A hydrogen generation system according to claim 1, The reaction apparatus comprises a plurality of reactors connected in parallel, A hydrogen generation system in which each of the multiple reactors is capable of producing hydrogen by an ammonolithesis reaction.

3. A hydrogen generation system according to claim 2, The reaction apparatus, in each of the plurality of reactors, The ammonia supply process involves supplying ammonia from a supplier, A hydrogen generation step, which generates hydrogen from ammonia supplied by the ammonia supply step by an ammonia monolith reaction, A hydrogen generation system capable of performing a hydrogen supply step of supplying the hydrogen generated by the hydrogen generation step to the combustor.

4. A hydrogen generation system according to claim 3, The reaction apparatus comprises, in each of the plurality of reactors, a discharge passage for discharging hydrogen produced in the reactor, and a discharge valve for opening and closing the discharge passage, and the hydrogen production process is performed with the discharge valve closed.

5. A hydrogen generation system according to claim 3 or 4, The reaction apparatus is a hydrogen generation system in which the ammonia supply step, the hydrogen generation step, and the hydrogen supply step are repeatedly performed in each of the plurality of reactors.

6. A hydrogen generation system according to claim 3 or 4, The reaction apparatus is a hydrogen generation system that performs the hydrogen supply process in one of the plurality of reactors and the hydrogen supply process in any of the other reactors at different timings.

7. A hydrogen generation system according to claim 6, The reaction apparatus is a hydrogen generation system that starts the hydrogen supply process in any of the reactors while the hydrogen supply process is being performed in any of the reactors.

8. A hydrogen generation system according to claim 3 or 4, The reaction apparatus includes a pressure sensor for detecting the gas pressure in at least one of the plurality of reactors, and when the hydrogen supply process is being performed in the at least one reactor, the hydrogen production system terminates the hydrogen supply process being performed based on the pressure detected by the pressure sensor.

9. A hydrogen generation system according to claim 8, The reaction apparatus is a hydrogen generation system that terminates the hydrogen supply process being performed when the time derivative of the pressure detected by the pressure sensor falls below a predetermined threshold.

10. A hydrogen generation system according to claim 3 or 4, The reaction apparatus is a hydrogen generation system that performs the ammonia supply process in one of the reactors while the hydrogen supply process is being performed in one of the reactors among the plurality of reactors.

11. A hydrogen generation system according to claim 3 or 4, The reaction apparatus includes a concentration sensor for detecting the ammonia concentration in at least one of the plurality of reactors, and when the hydrogen supply process and the ammonia supply process are being performed together in the at least one reactor, the hydrogen production system terminates the hydrogen supply process being performed based on the concentration detected by the concentration sensor.

12. A hydrogen generation system according to claim 11, The reaction apparatus is a hydrogen generation system that terminates the hydrogen supply process being performed when the time derivative of the concentration detected by the concentration sensor falls below a predetermined threshold.

Images