ammonia treatment system

Abstract

This technology provides a simple configuration that enables hydrogen generation and alkali metal hydride regeneration. [Solution] The ammonia treatment system comprises a reactor containing alkali metal hydride as a reactant, a reformer that generates high-temperature hydrogen by reforming ammonia, and a first supply channel that supplies the high-temperature hydrogen generated in the reformer to the reactor. The system is capable of performing a first operation in which ammonia is supplied to the reactor, and a second operation in which ammonia is supplied to the reformer and the high-temperature hydrogen generated in the reformer is supplied to the reactor via the first supply channel. In the first operation, hydrogen is generated in the reactor by an ammonia-monolithesis reaction between alkali metal hydride and ammonia, and in the second operation, alkali metal hydride is regenerated in the reactor by the reverse reaction of the ammonia-monolithesis reaction.

Description

Technical Field

[0001] The technology disclosed in this specification relates to an ammonia treatment system.

Background Art

[0002] Patent Document 1 discloses a technology for generating hydrogen by an ammonolysis reaction of an alkali metal hydride and ammonia. Further, Patent Document 1 discloses a technology for regenerating an alkali metal hydride by a reverse reaction of the ammonolysis reaction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the configuration of Patent Document 1, it is necessary to supply ammonia for the ammonolysis reaction and hydrogen for the reverse reaction of the ammonolysis reaction from different devices. With such a configuration, the configuration of the device becomes complicated. This specification provides a technology capable of generating hydrogen and regenerating an alkali metal hydride with a simple configuration.

Means for Solving the Problems

[0005] In a first aspect of this technology, the ammonia treatment system comprises a reformer that generates high-temperature hydrogen by reforming ammonia, a reactor containing alkali metal hydride as a reactant, and a first supply channel that supplies the high-temperature hydrogen generated in the reformer to the reactor. The ammonia treatment system is capable of performing a first operation in which ammonia is supplied to the reactor, and a second operation in which ammonia is supplied to the reformer and the high-temperature hydrogen generated in the reformer is supplied to the reactor through the first supply channel. In the first operation, hydrogen is generated in the reactor by an ammonia-monolithesis reaction between alkali metal hydride and ammonia. In the second operation, alkali metal hydride is regenerated in the reactor by the reverse reaction of the ammonia-monolithesis reaction.

[0006] This configuration allows for the regeneration of alkali metal hydride in the reactor using the high-temperature hydrogen produced in the reformer, provided that a first supply channel is included. This enables the generation of hydrogen in the first operation and the regeneration of alkali metal hydride in the second operation within a single system. Therefore, hydrogen generation and alkali metal hydride regeneration can be achieved with a simple configuration.

[0007] In a second embodiment, the ammonia treatment system may further include, in the first embodiment, a combustor that generates high-temperature steam by combustion of hydrogen, a second supply channel that supplies hydrogen produced in the reactor to the combustor, a heater that heats the ammonia in the reformer with the heat of the steam, and a third supply channel that supplies high-temperature steam produced in the combustor to the heater. In the first operation, the ammonia treatment system supplies hydrogen produced in the reactor to the combustor via the second supply channel, and supplies high-temperature steam produced in the combustor to the heater via the third supply channel.

[0008] This configuration allows the hydrogen produced by the ammonolithesis reaction in the reactor to be used to heat the ammonia in the reformer. This enables efficient heating of the ammonia in the reformer and promotes the reforming of the ammonia in the reformer.

[0009] In a third embodiment, in the first or second embodiment described above, the ammonia treatment system may further include an adsorbent for adsorbing ammonia contained in the gas discharged from the reactor during the first operation.

[0010] This configuration makes it possible to suppress the supply of ammonia from the reactor to the combustor. This, in turn, suppresses the generation of nitrogen oxides (NOx) in the combustor.

[0011] In a fourth embodiment, the ammonia treatment system may further include a fourth supply channel for supplying the gas discharged from the adsorbent to the reformer, as in the third embodiment. In the second operation, the ammonia treatment system may supply the gas remaining after the ammonia adsorbed on the adsorbent has been desorbed into the gas discharged from the reactor to the reformer via the fourth supply channel. With this configuration, the ammonia adsorbed in the adsorbent can be reused and reformed in the reformer.

[0012] In a fifth embodiment, in any one of the second to fourth embodiments, the ammonia treatment system may further include a temperature sensor for detecting the temperature of ammonia in the reformer. The ammonia treatment system may supply ammonia to the reformer when the temperature detected by the temperature sensor becomes equal to or above a predetermined reference temperature by performing the first operation. With this configuration, the reforming of ammonia in the reformer can be carried out at an appropriate temperature.

[0013] In the sixth embodiment, in any one of the first to fifth embodiments, the ammonia treatment system may further include a concentration sensor for detecting the concentration of ammonia contained in the gas discharged from the reactor. When the ammonia treatment system is performing the second operation, it may terminate the second operation based on the concentration detected by the concentration sensor.

[0014] In the second operation, once the reverse reaction of the ammonolithesis reaction has sufficiently progressed in the reactor and the alkali metal hydride in the reactor has been sufficiently regenerated, hydrogen consumption in the reactor becomes less likely. As a result, the concentration of hydrogen in the gas discharged from the reactor increases, and consequently, the concentration of ammonia in the gas discharged from the reactor does not increase as much. Furthermore, as the reverse reaction of the ammonolithesis reaction progresses, the concentration of ammonia in the gas discharged from the reactor decreases. Therefore, with the above configuration, by terminating the second operation based on the concentration detected by the concentration sensor, the second operation can be terminated at the appropriate time when the alkali metal hydride in the reactor has been sufficiently regenerated. In addition, it is possible to suppress the supply of hydrogen generated in the reformer to the reactor more than necessary.

[0015] In the seventh embodiment, in the sixth embodiment, the ammonia treatment system may terminate the second operation when the time derivative of the concentration detected by the concentration sensor falls below a predetermined threshold. With this configuration, the second operation can be terminated at a time when alkali metal hydride has been sufficiently regenerated in the reactor.

[0016] In the eighth aspect, the ammonia treatment system may include a reformer that generates high-temperature hydrogen by reforming ammonia, a first ammonia supply channel that supplies ammonia to the reformer, a reactor containing alkali metal hydride as a reactant, a second ammonia supply channel that supplies ammonia to the reactor, a first supply channel that supplies the high-temperature hydrogen generated in the reformer to the reactor, and a flow control valve provided in the first supply channel. [Brief explanation of the drawing]

[0017] [Figure 1] A schematic diagram showing the ammonia treatment system of the example. [Figure 2] A schematic diagram showing the first operation of the ammonia treatment system in the example. [Figure 3]A diagram schematically showing the non-desorption operation in the second operation of the ammonia treatment system of the embodiment. [Figure 4] A diagram schematically showing the desorption operation in the second operation of the ammonia treatment system of the embodiment. [Figure 5] A diagram schematically showing the reactor of the modified example.

Mode for Carrying Out the Invention

[0018] The ammonia treatment system 2 of the embodiment will be described with reference to the drawings. As shown in FIG. 1, the ammonia treatment 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 ammonia treatment system 2 is a system that generates hydrogen by the reformer 8 and supplies the generated hydrogen to the fuel cell 22. The control device 100 includes, for example, a CPU, a ROM, and a RAM, and executes control and processing related to each element of the ammonia treatment system 2 based on a predetermined program.

[0019] Each element of the ammonia treatment system 2 will be described. The ammonia tank 4 stores ammonia gas as a raw material. A first ammonia supply path 30 through which ammonia gas flows is connected to the ammonia tank 4. The upstream end of the first ammonia supply path 30 is connected to the ammonia tank 4, and the downstream end is connected to the reformer 8. The first ammonia supply path 30 supplies ammonia gas from the ammonia tank 4 to the reformer 8.

[0020] A first flow rate control valve 68 for controlling the flow rate of the ammonia gas flowing through the first ammonia supply path 30 is provided in the first ammonia supply path 30. When the first flow rate control valve 68 is in the open state, ammonia gas is supplied from the ammonia tank 4 to the reformer 8 through the first ammonia supply path 30. The ammonia gas in the first ammonia supply path 30 flows downstream due to the pressure of the ammonia gas stored in the ammonia tank 4 and is supplied to the reformer 8.

[0021] The reformer 8 generates the first fuel gas by reforming the ammonia gas supplied through the first ammonia supply passage 30. The configuration of the reformer 8 is not particularly limited. The reformer 8 includes, for example, a container and one or more catalysts disposed within the container. The catalyst used for reforming the ammonia gas is, for example, copper, nickel, ruthenium, or the like. The first fuel gas generated by the reformer 8 contains high-temperature hydrogen generated by reforming ammonia. The first fuel gas also contains unreacted ammonia. The ratio of hydrogen to ammonia contained in the first fuel gas varies depending on the progress of the reforming in the reformer 8.

[0022] The reformer 8 is provided with a temperature sensor 80 that detects the temperature of the ammonia gas in the reformer 8. The reformer 8 is also connected to a first fuel gas supply passage 34 through which the first fuel gas flows. The upstream end of the first fuel gas supply passage 34 is connected to the reformer 8, and the downstream end is connected to the first adsorber 18. The first fuel gas supply passage 34 supplies the first fuel gas from the reformer 8 to the first adsorber 18.

[0023] The first adsorber 18 removes ammonia from the first fuel gas by adsorbing the ammonia contained in the first fuel gas supplied through the first fuel gas supply passage 34 with an adsorbent. Thereby, the concentration of ammonia in the first fuel gas decreases. The configuration of the first adsorber 18 is not particularly limited. The first adsorber 18 includes, for example, a container and one or more adsorbents disposed within the container. The adsorbent used for adsorbing ammonia is, for example, activated carbon, zeolite, MOF (Metal Organic Framework), or the like.

[0024] 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.

[0025] 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.

[0026] 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 is omitted.

[0027] Other elements of the ammonia treatment system 2 will now be described. Upstream of the first flow control valve 68, the first ammonia supply channel 30 is connected to the second ammonia supply channel 32 through which ammonia gas flows. 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.

[0028] 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 second flow control valve 70 is 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.

[0029] In the first operation described later, reactor 10 generates a second fuel gas by decomposing the 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. The ammonia 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)

[0030] Reactor 10 contains alkali metal hydride as a reactant. The configuration of reactor 10 is not particularly limited. For example, reactor 10 comprises a vessel and one or more alkali metal hydride placed inside the vessel. The second fuel gas produced in reactor 10 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 reactor 10. The ammonolithesis reaction proceeds even at room temperature. Furthermore, the ammonolithesis reaction is an exothermic and reversible reaction.

[0031] In the second operation described later, reactor 10 regenerates alkali metal hydride through a regeneration reaction using hydrogen and heat. More specifically, reactor 10 regenerates alkali metal hydride through the reverse reaction of the ammonolithesis reaction. The reverse reaction of the ammonolithesis reaction is a reaction in which alkali metal hydride is regenerated by a chemical reaction between alkali metal amide and hydrogen, as shown in chemical formula (1) above. Ammonia is also produced in the reverse reaction of the ammonolithesis reaction. The reverse reaction of the ammonolithesis reaction proceeds even at room temperature. Furthermore, the reverse reaction of the ammonolithesis reaction is an endothermic and reversible reaction.

[0032] A third fuel gas supply channel 40 through which the second fuel gas flows is connected to the reactor 10. 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 adsorbent 20. The third fuel gas supply channel 40 supplies the second fuel gas from the reactor 10 to the second adsorbent 20. The third fuel gas supply channel 40 is equipped with a concentration sensor 82 for detecting the concentration of ammonia contained in the gas discharged from the reactor 10. A first three-way valve 64 is provided in the third fuel gas supply channel 40 downstream of the concentration sensor 82.

[0033] 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.

[0034] 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. A second three-way valve 66 is provided in the fourth fuel gas supply channel 42.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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).

[0042] Next, the first branch supply channel 120, the second branch supply channel 122, and the third branch supply channel 124 will be described. The upstream end of the first branch supply channel 120 is connected to the first fuel gas supply channel 34, and the downstream end is connected to the second ammonia supply channel 32, which is downstream of the second flow control valve 70. The first branch supply channel 120 branches off from the first fuel gas supply channel 34 and extends to the second ammonia supply channel 32. In the first operation described later, the first branch supply channel 120 supplies the first fuel gas from the first fuel gas supply channel 34 to the second ammonia supply channel 32. A portion of the first fuel gas flowing through the first fuel gas supply channel 34 is supplied to the second ammonia supply channel 32 through the first branch supply channel 120, and then supplied to the reactor 10 through the second ammonia supply channel 32.

[0043] The first branch supply channel 120 is equipped with a third flow control valve 72 that controls the flow rate of the first fuel gas flowing through the first branch supply channel 120. When the first branch supply channel 120 is open, the first fuel gas is supplied from the first fuel gas supply channel 34 to the reactor 10 through the first branch supply channel 120 and the second ammonia supply channel 32.

[0044] The second branch supply line 122 has its upstream end connected to the first three-way valve 64 located in the third fuel gas supply line 40, and its downstream end connected to the first ammonia supply line 30. The second branch supply line 122 is connected to the third fuel gas supply line 40 via the first three-way valve 64. The second branch supply line 122 branches off from the third fuel gas supply line 40 and extends to the first ammonia supply line 30. In the non-deactivation operation of the second operation described later, the second branch supply line 122 supplies ammonia gas from the third fuel gas supply line 40 to the first ammonia supply line 30.

[0045] The first three-way valve 64 can be switched between a first state and a second state. In the first state of the first three-way valve 64, the third fuel gas supply passage 40 upstream of the first three-way valve 64 and the third fuel gas supply passage 40 downstream of the first three-way valve 64 are connected (the second branch supply passage 122 is not connected). In the second state of the first three-way valve 64, the third fuel gas supply passage 40 upstream of the first three-way valve 64 and the second branch supply passage 122 are connected (the third fuel gas supply passage 40 downstream of the first three-way valve 64 is not connected).

[0046] The third branch supply line 124 has its upstream end connected to a second three-way valve 66 located in the fourth fuel gas supply line 42, and its downstream end connected to the first ammonia supply line 30. The third branch supply line 124 is connected to the fourth fuel gas supply line 42 via the second three-way valve 66. The third branch supply line 124 branches off from the fourth fuel gas supply line 42 and extends to the first ammonia supply line 30. In the deactivation operation of the second operation described later, the third branch supply line 124 supplies ammonia gas from the fourth fuel gas supply line 42 to the first ammonia supply line 30.

[0047] The second three-way valve 66 can be switched between a first state and a second state. In the first state of the second three-way valve 66, the fourth fuel gas supply passage 42 upstream of the second three-way valve 66 and the fourth fuel gas supply passage 42 downstream of the second three-way valve 66 are connected (the third branch supply passage 124 is not connected). In the second state of the second three-way valve 66, the fourth fuel gas supply passage 42 upstream of the second three-way valve 66 and the third branch supply passage 124 are connected (the fourth fuel gas supply passage 42 downstream of the second three-way valve 66 is not connected).

[0048] Next, the operation of the ammonia treatment system 2 will be described. The ammonia treatment system 2 can perform a first operation and a second operation. The first operation is an operation in which ammonia is supplied to the reactor 10 and hydrogen is produced in the reactor 10 by an ammonia monolithy reaction between alkali metal hydride and ammonia. The second operation is an operation in which high-temperature hydrogen produced in the reformer 8 is supplied to the reactor 10 without supplying ammonia to the reactor 10 and alkali metal hydride is regenerated in the reactor 10 by the reverse reaction of the ammonia monolithy reaction.

[0049] (First operation; Figure 2) The first operation will now be described in detail. In the first operation, the control device 100 of the ammonia treatment system 2 opens the second flow control valve 70 located in the second ammonia supply passage 32. Also in the first operation, the control device 100 sets the first three-way valve 64 located in the third fuel gas supply passage 40 to the first state, and also sets the second three-way valve 66 located in the fourth fuel gas supply passage 42 to the first state.

[0050] In the first operation, the control device 100 closes the third flow control valve 72 located in the first branch supply line 120. Also in the first operation, if the temperature detected by the temperature sensor 80 located in the reformer 8 is below a predetermined reference temperature, the control device 100 opens the first flow control valve 68 located in the first ammonia supply line 30.

[0051] As shown in Figure 2, in the first operation, the second flow control valve 70 opens, and ammonia gas stored in the ammonia tank 4 is supplied to the reactor 10 through the second ammonia supply passage 32. In the reactor 10, a second fuel gas is produced by the ammonia monolithy reaction of ammonia gas. The second fuel gas produced in the reactor 10 contains hydrogen produced by the ammonia monolithy reaction of ammonia. The second fuel gas also contains undecomposed ammonia.

[0052] The second fuel gas generated in reactor 10 is supplied to the second adsorbent 20 through the third fuel gas supply passage 40 when the first three-way valve 64 enters the first state. 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.

[0053] 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 when the second three-way valve 66 enters the first state. In the combustor 12, combustion gas is generated by the combustion of the second fuel gas. The combustion gas generated in the combustor 12 contains high-temperature water vapor produced by the combustion of hydrogen contained in the second fuel gas.

[0054] 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.

[0055] When the control device 100 performs the above-described first operation and the temperature detected by the temperature sensor 80 rises to or above a predetermined reference temperature, it opens the first flow control valve 68 located in the first ammonia supply passage 30. When the first flow control valve 68 is open, ammonia gas stored in the ammonia tank 4 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.

[0056] The first fuel gas generated in the reformer 8 is supplied to the first adsorbent 18 through the first fuel gas supply line 34. In the first adsorbent 18, ammonia contained in the first fuel gas is adsorbed and removed. This reduces the concentration of ammonia in the first fuel gas.

[0057] 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.

[0058] (Second operation; Figures 3 and 4) Next, the second operation will be described in detail. In the second operation, the control device 100 closes the second flow control valve 70 located in the second ammonia supply passage 32. In the second operation, the control device 100 also opens the first flow control valve 68 located in the first ammonia supply passage 30. In the second operation, the control device 100 also opens the third flow control valve 72 located in the first branch supply passage 120.

[0059] As shown in Figures 3 and 4, in the second operation, the first flow control valve 68 opens, and the ammonia gas stored in the ammonia tank 4 is supplied to the reformer 8 through the first ammonia supply passage 30. In the reformer 8, the 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.

[0060] The first fuel gas generated in the reformer 8 is supplied to the first adsorbent 18 through the first fuel gas supply line 34. In the first adsorbent 18, ammonia contained in the first fuel gas is adsorbed and removed. This reduces the concentration of ammonia in the first fuel gas.

[0061] 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.

[0062] In the second operation, the third flow control valve 72 opens, allowing a portion of the first fuel gas generated in the reformer 8 to be supplied to the reactor 10 through the first branch supply line 120 and the second ammonia supply line 32. This supplies high-temperature hydrogen generated in the reformer 8 to the reactor 10. In the reactor 10, alkali metal hydride is regenerated by the reverse reaction of the ammonolithesis reaction using hydrogen and heat. Ammonia gas is also generated in the reactor 10 by the reverse reaction of the ammonolithesis reaction.

[0063] The ammonia treatment system 2 can perform both desorption and non-desorption operations during the second operation. Desorption operation is an operation in which ammonia adsorbed on the second adsorbent 20 is desorbed into ammonia gas discharged from the reactor 10. Non-desorption operation is an operation in which ammonia adsorbed on the second adsorbent 20 is not desorbed.

[0064] (Detachment operation; Figure 3) Next, the deactivation operation will be explained in detail. In the deactivation operation, the control device 100 sets the first three-way valve 64, which is installed in the third fuel gas supply passage 40, to the first state, and the second three-way valve 66, which is installed in the fourth fuel gas supply passage 42, to the second state.

[0065] When the first three-way valve 64 enters the first state, the ammonia gas produced in the reactor 10 is supplied to the second adsorbent 20 through the third fuel gas supply passage 40. In the second adsorbent 20, the ammonia adsorbed on the adsorbent is desorbed into the ammonia gas. As a result, the concentration of ammonia in the ammonia gas increases.

[0066] The ammonia gas containing ammonia desorbed from the second adsorbent 20 is supplied to the reformer 8 through the third branch supply line 124 and the first ammonia supply line 30 when the second three-way valve 66 enters the second state. In the reformer 8, the first fuel gas is produced by reforming the ammonia gas. The first fuel gas produced in the reformer 8 is supplied to the first adsorbent 18 through the first fuel gas supply line 34. In the first adsorbent 18, as described above, the ammonia contained in the first fuel gas is adsorbed and removed. In addition, a portion of the first fuel gas produced in the reformer 8 is supplied to the reactor 10 through the first branch supply line 120 and the second ammonia supply line 32. In the reactor 10, as described above, alkali metal hydride is regenerated by the reverse reaction of the ammonia monolith reaction using hydrogen and heat.

[0067] (Non-detachable operation; Figure 4) Next, the non-desorption operation will be described in detail. In non-desorption operation, the control device 100 sets the first three-way valve 64, which is located in the third fuel gas supply line 40, to the second state. As shown in Figure 4, in non-desorption operation, when the first three-way valve 64 is in the second state, the ammonia gas produced in the reactor 10 is supplied to the reformer 8 through the second branch supply line 122 and the first ammonia supply line 30. In the reformer 8, the first fuel gas is produced by reforming the ammonia gas. The first fuel gas produced in the reformer 8 is supplied to the first adsorbent 18 through the first fuel gas supply line 34. In the first adsorbent 18, as described above, the ammonia contained in the first fuel gas is adsorbed and removed. In addition, a portion of the first fuel gas produced in the reformer 8 is supplied to the reactor 10 through the first branch supply line 120 and the second ammonia supply line 32. In reactor 10, as described above, alkali metal hydride is regenerated by the reverse reaction of the ammonolithesis reaction using hydrogen and heat.

[0068] (effect) The ammonia treatment system 2 of the embodiment has been described above. As is clear from the above description, the ammonia treatment system 2 is capable of performing a first operation in which ammonia is supplied to the reactor 10. The ammonia treatment system 2 is also capable of performing a second operation in which ammonia is supplied to the reformer 8 and the high-temperature hydrogen produced in the reformer 8 is supplied to the reactor 10 via the first branch supply line 120. In the first operation, hydrogen is produced in the reactor 10 by an ammonia monolysis reaction between alkali metal hydride and ammonia. In the second operation, alkali metal hydride is regenerated in the reactor 10 by the reverse reaction of the ammonia monolysis reaction.

[0069] With this configuration, by providing a first branch supply line 120, the high-temperature hydrogen produced in the reformer 8 can be used to regenerate the alkali metal hydride in the reactor 10. This allows for the generation of hydrogen in the first operation and the regeneration of alkali metal hydride in the second operation within a single system. Therefore, hydrogen generation and alkali metal hydride regeneration can be achieved with a simple configuration.

[0070] In addition, during the first operation, the ammonia treatment system 2 supplies hydrogen produced in the reactor 10 to the combustor 12 via the third fuel gas supply line 40 and the fourth fuel gas supply line 42, and supplies high-temperature steam produced in the combustor 12 to the heater 16 via the combustion gas supply line 44. The heater 16 heats the ammonia in the reformer 8 with the heat of the steam.

[0071] With this configuration, the hydrogen produced by the ammonolithesis reaction in reactor 10 can be used to heat the ammonia in reformer 8. This allows for efficient heating of the ammonia in reformer 8 and promotes the reforming of the ammonia in reformer 8.

[0072] Furthermore, the ammonia treatment system 2 includes a second adsorbent 20 that adsorbs ammonia contained in the gas discharged from the reactor 10 during the first operation. This configuration makes it possible to suppress the supply of ammonia from the reactor 10 to the combustor 12. As a result, it is possible to suppress the generation of nitrogen oxides (NOx) in the combustor 12.

[0073] Furthermore, in the second operation, the ammonia treatment system 2 supplies the ammonia gas, which is the ammonia gas discharged from the reactor 10 after the ammonia adsorbed in the second adsorbent 20 has been desorbed, to the reformer 8 via the third branch supply path 124. With this configuration, the ammonia adsorbed in the second adsorbent 20 can be reused and reformed in the reformer 8.

[0074] The ammonia treatment system 2 supplies ammonia to the reformer 8 when the temperature detected by the temperature sensor 80 reaches or exceeds a predetermined reference temperature during the first operation. With this configuration, the ammonia reforming in the reformer 8 can be carried out at an appropriate temperature.

[0075] (Correspondence) The first branch supply line 120 is an example of a "first supply line". The third fuel gas supply line 40 and the fourth fuel gas supply line 42 are examples of a "second supply line". The combustion gas supply line 44 is an example of a "third supply line". The third branch supply line 124 is an example of a "fourth supply line".

[0076] (modified version) (1) When the ammonia treatment system 2 is performing the second operation, it may terminate the second operation based on the concentration detected by the concentration sensor 82. More specifically, when the control device 100 is performing the second operation, it may terminate the second operation if the time derivative value of the concentration detected by the concentration sensor 82 falls below a predetermined threshold during the increase in the concentration. The predetermined threshold is, for example, a positive value close to 0 (zero). The control device 100 may also terminate the second operation by closing the third flow control valve 72 provided in the first branch supply path 120.

[0077] In the second operation of the ammonia treatment system 2, the reverse reaction of the ammonia monolithion reaction proceeds in reactor 10, causing the concentration of ammonia in the gas discharged from reactor 10 to increase. However, as the reverse reaction of the ammonia monolithion reaction proceeds further in reactor 10 during the second operation, and the alkali metal hydride in reactor 10 is sufficiently regenerated, hydrogen consumption in reactor 10 becomes less likely. As a result, the concentration of hydrogen in the gas discharged from reactor 10 increases, and consequently, the concentration of ammonia in the gas discharged from reactor 10 becomes less likely to increase. Furthermore, as the reverse reaction of the ammonia monolithion reaction proceeds further, the concentration of ammonia in the gas discharged from reactor 10 decreases. Therefore, with the above configuration, by terminating the second operation based on the concentration detected by the concentration sensor 82, the second operation can be terminated at the appropriate time when the alkali metal hydride has been sufficiently regenerated in reactor 10. In addition, it is possible to suppress the supply of hydrogen generated in reformer 8 to reactor 10 more than necessary.

[0078] (2) In the above embodiment, ammonia gas was supplied from the ammonia tank 4 to the reformer 8 and also supplied from the ammonia tank 4 to the reactor 10, but the configuration is not limited to this. That is, in the above embodiment, the source of ammonia gas supplied to the reformer 8 and the source of ammonia gas supplied to the reactor 10 were the same source, but the source of ammonia gas is not particularly limited. The source of ammonia gas supplied to the reformer 8 and the source of ammonia gas supplied to the reactor 10 may be the same source or may be different sources.

[0079] (3) The number of reactors 10 in the ammonia treatment system 2 is not particularly limited. In a modified example, the ammonia treatment system 2 may have multiple reactors 10. In this case, the multiple reactors 10 may be connected in series. Alternatively, the multiple reactors 10 may be connected in parallel, as shown in Figure 5.

[0080] 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]

[0081] 2: Ammonia treatment 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, 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 discharge channel, 64: First three-way valve, 66: Second three-way valve, 68: First flow control valve, 70: Second flow control valve, 72: Third flow control valve, 80: Temperature sensor, 82: Concentration sensor, 100: Control device, 120: First branch supply channel, 122: Second branch supply channel, 124: Third branch supply channel

Claims

1. A reformer that generates high-temperature hydrogen by reforming ammonia, A reactor containing alkali metal hydride as a reactant, The reactor comprises a first supply channel for supplying high-temperature hydrogen produced in the reformer to the reactor, An ammonia treatment system capable of performing a first operation of supplying ammonia to the reactor and a second operation of supplying ammonia to the reformer and supplying high-temperature hydrogen produced in the reformer to the reactor through the first supply path, In the first operation, hydrogen is produced in the reactor by an ammoniacal reaction between alkali metal hydride and ammonia. In the second operation, alkali metal hydride is regenerated in the reactor by the reverse reaction of the ammonia monolith reaction in the ammonia treatment system.

2. The ammonia treatment system according to claim 1, A combustor that generates high-temperature steam by burning hydrogen, A second supply channel for supplying hydrogen produced in the reactor to the combustor, A heater that heats the ammonia in the reformer by the heat of steam, The system further comprises a third supply path for supplying high-temperature steam generated in the combustor to the heater, An ammonia treatment system in which, in the first operation, hydrogen produced in the reactor is supplied to the combustor through the second supply channel, and high-temperature steam produced in the combustor is supplied to the heater through the third supply channel.

3. An ammonia treatment system according to claim 1 or 2, An ammonia treatment system further comprising an adsorbent for adsorbing ammonia contained in the gas discharged from the reactor during the first operation.

4. The ammonia treatment system according to claim 3, The system further includes a fourth supply channel for supplying the gas discharged from the adsorbent to the reformer, The ammonia treatment system, in the second operation, supplies the gas remaining after the ammonia adsorbed on the adsorbent has been desorbed into the gas discharged from the reactor to the reformer via the fourth supply path.

5. The ammonia treatment system according to claim 2, The reformer further includes a temperature sensor for detecting the temperature of ammonia, The ammonia treatment system is an ammonia treatment system that supplies ammonia to the reformer when the temperature detected by the temperature sensor becomes equal to or above a predetermined reference temperature by performing the first operation.

6. An ammonia treatment system according to claim 1 or 2, The reactor is further equipped with a concentration sensor for detecting the concentration of ammonia contained in the gas discharged from the reactor. The ammonia treatment system is an ammonia treatment system that, when performing the second operation, terminates the second operation based on the concentration detected by the concentration sensor.

7. The ammonia treatment system according to claim 6, The ammonia treatment system is an ammonia treatment system that, when performing the second operation, terminates the second operation when the time derivative value of the concentration detected by the concentration sensor falls below a predetermined threshold.

8. A reformer that generates high-temperature hydrogen by reforming ammonia, A first ammonia supply path for supplying ammonia to the reformer, A reactor containing alkali metal hydride as a reactant, A second ammonia supply channel for supplying ammonia to the reactor, A first supply channel for supplying high-temperature hydrogen produced in the reformer to the reactor, An ammonia treatment system comprising a flow control valve provided in the first supply line.

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