Ammonia decomposition apparatus

Abstract

To make it possible to efficiently decompose ammonia into hydrogen and nitrogen in a decomposition vessel that houses catalyst which decomposes ammonia into hydrogen and nitrogen.SOLUTION: In an ammonia decomposition apparatus that decomposes ammonia NH3 into hydrogen H2 and nitrogen N2 in a decomposition vessel 10, a plurality of stages of catalyst layers 20 using catalyst 21, which decompose ammonia into hydrogen and nitrogen via a required interval in a flow direction of ammonia flowing in a decomposition vessel, are provided in the decomposition vessel, and a heater which heats the inside of the decomposition vessel is provided.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an ammonia decomposition apparatus for decomposing ammonia into hydrogen and nitrogen in a decomposition vessel. In particular, the present invention is an ammonia decomposition apparatus characterized in that, when ammonia is used as fuel, ammonia can be efficiently decomposed into hydrogen and nitrogen in a decomposition vessel containing a catalyst for decomposing ammonia into hydrogen and nitrogen. [Background technology]

[0002] 2. Description of the Related Art Combustion devices that mix fuel with combustion air and combust the mixture generally use hydrocarbon fuels as the fuel.

[0003] However, when a hydrocarbon fuel is mixed with combustion air and burned in such a combustion device, there is a problem in that a large amount of greenhouse gases such as carbon dioxide is generated.

[0004] For this reason, ammonia has conventionally been used as fuel in combustion devices.

[0005] However, ammonia has poor combustibility compared to hydrocarbon fuels, making it difficult to completely combust it. It is also prone to misfires when burned at low temperatures. Meanwhile, when it is burned vigorously, the flame temperature becomes high, resulting in increased amounts of NOx being generated.

[0006] For this reason, in the past, as shown in Patent Document 1, ammonia was introduced into a reactor filled with a catalyst that decomposes ammonia into hydrogen and nitrogen, and ammonia was mixed with a heated dilution gas to dilute it before being decomposed into hydrogen and nitrogen.

[0007] However, even if the heated dilution gas is mixed with ammonia and introduced into the reactor, it is difficult to sufficiently decompose the ammonia into hydrogen and nitrogen.

[0008] Furthermore, Patent Document 2 discloses a system in which a heating device is provided on the outer periphery of a catalyst housing section that houses a catalyst that decomposes ammonia into hydrogen and nitrogen, and the catalyst housed in the catalyst housing section is heated by the heating device when the ammonia is decomposed into hydrogen and nitrogen.

[0009] However, when the catalyst contained in the catalyst containing section is heated by a heating device provided on the outer periphery of the catalyst containing section, if the diameter of the catalyst containing section becomes large, the catalyst in the center of the catalyst containing section is not heated sufficiently and is not activated, making it difficult to sufficiently decompose the ammonia passing through the catalyst containing section into hydrogen and nitrogen.

[0010] Moreover, Patent Documents 3 and 4 disclose a catalyst container that contains a catalyst and is heated from the surroundings.

[0011] However, like the device shown in Patent Document 2, the devices shown in Patent Documents 3 and 4 had the problem that when the diameter of the catalyst containing section became large, the catalyst in the center of the catalyst containing section was not heated sufficiently and was not activated. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Patent Publication No. 2022-109042 [Patent Document 2] JP 2023-39681 A [Patent Document 3] WO2011 / 052020 publication [Patent Document 4] JP 2012-57508 A DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0013] An object of the present invention is to solve the above-mentioned problems in an ammonia decomposition apparatus that decomposes ammonia into hydrogen and nitrogen in a decomposition vessel.

[0014] That is, an object of the present invention is to provide an ammonia decomposition apparatus as described above, in which ammonia can be efficiently decomposed into hydrogen and nitrogen in a decomposition vessel containing a catalyst for decomposing ammonia into hydrogen and nitrogen. [Means for solving the problem]

[0015] In order to solve the above-mentioned problems, in the ammonia decomposition apparatus according to the present invention, in an ammonia decomposition vessel in which ammonia is decomposed into hydrogen and nitrogen, catalytic layers using a catalyst for decomposing ammonia into hydrogen and nitrogen are provided in a plurality of stages in the decomposition vessel at required intervals in the flow direction of ammonia flowing through the decomposition vessel, and a heating device for heating the inside of the decomposition vessel is provided.

[0016] In this way, when catalytic layers using a catalyst that decomposes ammonia into hydrogen and nitrogen are provided in multiple stages in the decomposition vessel at required intervals in the flow direction of ammonia flowing inside the decomposition vessel, the catalytic layers are heated by heat from the heating device, and the heat from the heating device is also transmitted to the central parts of each catalytic layer in the decomposition vessel through the parts between the catalytic layers, so that the central parts of the catalytic layers are also sufficiently heated to activate the catalyst, and the ammonia flowing inside the decomposition vessel is efficiently decomposed into hydrogen and nitrogen through each catalytic layer.

[0017] Here, in the ammonia decomposition apparatus of the present invention, when providing a heating device for heating the inside of the decomposition vessel as described above, the heating device can be provided on the outer periphery of the decomposition vessel, and a heat insulator can be provided on the outer periphery of the heating device.

[0018] In addition, in the ammonia decomposition apparatus of the present invention, when a heating device for heating the inside of the decomposition vessel is provided as described above, when catalyst beds are provided in a plurality of stages in the decomposition vessel at required intervals in the direction of ammonia flow, the catalyst beds can be provided at required intervals in the vertical direction in the decomposition vessel.

[0019] In the ammonia decomposition apparatus of the present invention, when the catalytic layers are arranged in a plurality of stages at required intervals in the direction of ammonia flow in the decomposition vessel, a holding means for holding the catalytic layers can be provided in the decomposition vessel and spaces can be provided between the catalytic layers. In this way, the catalytic layers are heated by heat from the heating device as described above, and the heat from the heating device is also transmitted to the central parts of the catalytic layers in the decomposition vessel through the spaces between the catalytic layers, so that the entire catalytic layers are sufficiently heated to activate the catalyst, and the ammonia flowing in the decomposition vessel is efficiently decomposed into hydrogen and nitrogen through the catalytic layers.

[0020] In the ammonia decomposition apparatus of the present invention, when the catalytic layers are arranged in a plurality of stages at required intervals in the ammonia flow direction in the decomposition vessel, a heat storage body having gas permeability can be provided between the catalytic layers. In this way, the heat storage body provided between the catalytic layers is heated and stored together with the catalytic layers by the heat from the heating device, and the ammonia flowing in the decomposition vessel is heated by the heat stored in the heat storage body provided between the catalytic layers, so that the ammonia flowing in the decomposition vessel is efficiently decomposed into hydrogen and nitrogen through each catalytic layer. In particular, when the heat storage body having gas permeability is provided on both sides of the catalytic layer in the ammonia flow direction, the ammonia flowing in the decomposition vessel is heated by the heat stored in each heat storage body provided on both sides of the catalytic layer, so that the ammonia flowing in the decomposition vessel is more efficiently decomposed into hydrogen and nitrogen. Effect of the Invention

[0021] In the ammonia decomposition apparatus according to the present invention, catalytic layers using a catalyst that decomposes ammonia into hydrogen and nitrogen are provided in a plurality of stages in the decomposition vessel at required intervals in the flow direction of ammonia flowing through the decomposition vessel as described above, and a heating device is provided for heating the inside of the decomposition vessel. Therefore, the catalytic layers are heated by heat from the heating device, and the heat from the heating device is also transmitted to the central parts of each catalytic layer in the decomposition vessel through the parts between the catalytic layers, so that each catalytic layer is sufficiently heated as a whole to activate the catalyst.

[0022] As a result, in the ammonia decomposition apparatus of the present invention, ammonia introduced into the decomposition vessel is efficiently decomposed into hydrogen and nitrogen by the catalyst in each catalyst layer which has been heated to its center and activated. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 is a schematic cross-sectional view illustrating an ammonia decomposition apparatus according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic cross-sectional explanatory view showing a first modified example of the ammonia decomposition apparatus according to the first embodiment. [Diagram 3] FIG. 4 is a schematic cross-sectional view showing an ammonia decomposition apparatus according to a second embodiment of the present invention. [Figure 4] FIG. 2 is a schematic cross-sectional view showing a second modified example of the ammonia decomposition apparatus according to the second embodiment. BEST MODE FOR CARRYING OUT THEINVENTION

[0024] Hereinafter, an ammonia decomposition apparatus according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Note that the ammonia decomposition apparatus according to the present invention is not limited to the following embodiment, and can be appropriately modified and implemented within the scope of the invention.

[0025] (Embodiment 1) In the ammonia decomposition apparatus according to the first embodiment, as shown in FIG. 1, when ammonia NH3 is decomposed into hydrogen H2 and nitrogen N2 in a decomposition vessel 10, an inlet 11 for introducing ammonia NH3 is provided at the bottom of the decomposition vessel 10, while an outlet 12 for taking out hydrogen H2 and nitrogen N2 resulting from the decomposition of ammonia NH3 is provided at the top of the decomposition vessel 10. Ammonia NH3 is introduced into the decomposition vessel 10 through the inlet 11, and the introduced ammonia NH3 is decomposed into hydrogen H2 and nitrogen N2 in the decomposition vessel 10, and the decomposed hydrogen H2 and nitrogen N2 are taken out from the outlet 12.

[0026] Here, in the ammonia decomposition apparatus according to the first embodiment, catalyst layers 20 using catalysts 21 that decompose ammonia NH3 into hydrogen H2 and nitrogen N2 are provided in the decomposition vessel 10 at required intervals in the flow direction of ammonia NH3. A pellet-shaped catalyst 21a is used as the catalyst 21, and a gas-permeable holding member 31 such as a grating that holds the pellet-shaped catalyst 21a so as not to spill out is provided in the decomposition vessel 10 at required intervals in the vertical direction, which is the flow direction of ammonia NH3, in a plurality of stages (three stages in the example shown in the figure). The pellet-shaped catalyst 21a is stacked on each holding member 31 thus provided to an appropriate thickness to provide a plurality of stages (three stages in the example shown in the figure) of catalyst layers 20, and a space 22 is provided between each catalyst layer 20.

[0027] In the ammonia decomposition apparatus according to the first embodiment, a heating device 40 consisting of a heater for heating the inside of the decomposition vessel 10 is provided on the outer periphery of the decomposition vessel 10, and a heat insulator 41 is provided on the outer periphery of the heating device 40 so that the heat generated by the heating device 40 is not dissipated to the outside, thereby efficiently heating each catalyst layer 20 and each space 22 between the catalyst layers 20 provided in the decomposition vessel 10.

[0028] In the ammonia decomposition apparatus according to the first embodiment, ammonia NH3 is introduced into the decomposition vessel 10 from the inlet 11 provided at the bottom of the decomposition vessel 10 while the inside of the decomposition vessel 10 is heated by the heating device 40. The introduced ammonia NH3 is guided through the first catalyst layer 20a, the first space 22a, the second catalyst layer 20b, the second space 22b, and the third catalyst layer 20c in this order within the decomposition vessel 10, and is decomposed into hydrogen H2 and nitrogen N2 while being heated. The ammonia NH3 is then taken out from the outlet 12 provided at the top of the decomposition vessel 10.

[0029] Here, when the catalyst layers 20 (20a-20c) and the spaces 22 (22a, 22b) provided in the decomposition vessel 10 are heated by the heating device 40 provided on the outer periphery of the decomposition vessel 10 as described above, the heat from the heating device 40 is transmitted to the central parts of the catalyst layers 20 (20a-20c) through the spaces 22 (22a, 22b), and the entire catalyst layers 20 (20a-20c) are sufficiently heated to activate the catalysts 21.

[0030] As a result, while the inside of the decomposition vessel 10 is being heated by the heating device 40 as described above, ammonia NH3 introduced from the inlet 11 at the bottom of the decomposition vessel 10 is guided in the order of the first catalyst layer 20a, the first space 22a, the second catalyst layer 20b, the second space 22b, and the third catalyst layer 20c in the decomposition vessel 10. The catalysts 21a are sufficiently heated and activated as a whole, and the ammonia NH3 can be efficiently decomposed into hydrogen H2 and nitrogen N2, and the ammonia NH3 can be taken out from the outlet 12.

[0031] Here, in the ammonia decomposition apparatus according to the first embodiment, the pellet-shaped catalyst 21a is used as the catalyst 21 in the catalyst layer 20, but the catalyst 21 used is not limited to this.

[0032] For example, in modified example 1 shown in FIG. 2, a honeycomb-shaped catalyst 21b having air permeability in the flow direction of ammonia NH3 is used as the catalyst 21, and a catalyst layer 20 formed into a predetermined shape is used. The catalyst layer 20 thus formed is held on a holding protrusion 32 protruding from the inner circumference of the decomposition vessel 10, and the catalyst layer 20 is provided in the decomposition vessel 10 in a plurality of stages (three stages in the example shown in the figure) at required intervals in the vertical direction, which is the flow direction of ammonia NH3, and a space 22 is provided between each catalyst layer 20.

[0033] Here, in the modified example 1 shown in FIG. 2, similarly to the embodiment 1 shown in FIG. 1, a heating device 40 consisting of a heater for heating the inside of the decomposition vessel 10 is provided on the outer periphery of the decomposition vessel 10, and a heat insulator 41 is provided on the outer periphery of the heating device 40 so that the heat generated by the heating device 40 is not dissipated to the outside, thereby efficiently heating each catalyst layer 20 provided in the decomposition vessel 10 and each space 22 between the catalyst layers 20.

[0034] In the ammonia decomposition apparatus according to the first modified example, similarly to the first embodiment, while the inside of the decomposition vessel 10 is heated by the heating device 40, ammonia NH3 is introduced into the decomposition vessel 10 through the inlet 11 provided at the bottom of the decomposition vessel 10, and the introduced ammonia NH3 is guided in this order through the first catalyst layer 20a, the first space 22a, the second catalyst layer 20b, the second space 22b, and the third catalyst layer 20c in the decomposition vessel 10, and is decomposed into hydrogen H2 and nitrogen N2 while being heated, and is taken out from the outlet 12 provided at the top of the decomposition vessel 10.

[0035] In this manner, in the ammonia decomposition apparatus of the first modified example, as in the first embodiment, ammonia NH3 introduced from the inlet 11 at the bottom of the decomposition vessel 10 is guided in this order to the first catalyst layer 20a, the first space 22a, the second catalyst layer 20b, the second space 22b, and the third catalyst layer 20c in the decomposition vessel 10, and the ammonia NH3 is efficiently decomposed into hydrogen H2 and nitrogen N2 by each catalyst 21b which is fully heated and activated as a whole, and can be taken out from the outlet 12.

[0036] In the above-described first embodiment and first modified example, the catalyst layers 20 are provided in the decomposition vessel 10 in three stages at required intervals in the vertical direction, which is the flow direction of ammonia NH3. However, the number of stages of the catalyst layers 20 provided in the decomposition vessel 10 is not particularly limited as long as a space 22 is formed between the catalyst layers 20. As long as the number of stages is two or more, more catalyst layers 20 can be provided.

[0037] In addition, in the above-mentioned embodiment 1 and modified example 1, the inlet 11 is provided at the bottom of the decomposition vessel 10 while the outlet 12 is provided at the top of the decomposition vessel 10. However, it is also possible to provide the inlet 11 at the top of the decomposition vessel 10 while providing the outlet 12 at the bottom of the decomposition vessel 10, and introduce ammonia NH3 into the decomposition vessel 10 from the inlet 11 at the top of the decomposition vessel 10, decompose it into hydrogen H2 and nitrogen N2 in the decomposition vessel 10, and take it out from the outlet 12 at the bottom of the decomposition vessel 10.

[0038] Furthermore, in the above-mentioned embodiment 1 and modified example 1, the inlet 11 and the outlet 12 are provided at the upper or lower part of the decomposition vessel 10, and a plurality of catalyst layers 20 are provided in the decomposition vessel 10 at required intervals in the vertical direction. However, the present invention is not limited to this. Although not shown, the decomposition vessel 10 can be laid horizontally, and the inlet 11 and the outlet 12 can be provided on both sides of the decomposition vessel 10 in the horizontal direction, and a plurality of catalyst layers 20 can be provided in the decomposition vessel 10 at required intervals in the horizontal direction.

[0039] (Embodiment 2) Also in the ammonia decomposition apparatus according to the second embodiment, as shown in FIG. 3, when ammonia NH3 is decomposed into hydrogen H2 and nitrogen N2 in the decomposition vessel 10, an inlet 11 for introducing ammonia NH3 is provided in the lower part of the decomposition vessel 10, and an outlet 12 for taking out hydrogen H2 and nitrogen N2 resulting from the decomposition of ammonia NH3 is provided in the upper part of the decomposition vessel 10. Ammonia NH3 is introduced into the decomposition vessel 10 through the inlet 11, and the introduced ammonia NH3 is decomposed into hydrogen H2 and nitrogen N2 in the decomposition vessel 10, and the decomposed hydrogen H2 and nitrogen N2 are taken out from the outlet 12.

[0040] Here, in the ammonia decomposition apparatus according to the second embodiment, a heat storage body 23 having gas permeability and a catalyst layer 20 using a catalyst 21 for decomposing ammonia NH3 into hydrogen H2 and nitrogen N2 are arranged in a plurality of stages alternately in the vertical direction, which is the flow direction of ammonia NH3, within the decomposition vessel 10.

[0041] In the ammonia decomposition apparatus according to the second embodiment, the heat storage body 23 is a honeycomb-shaped heat storage material 24a having air permeability in the flow direction of ammonia NH3, and the honeycomb-shaped heat storage material 24a is molded into a predetermined shape. In the catalyst layer 20, a pellet-shaped catalyst 21a is used as the catalyst 21. A first heat storage body 23a molded from the honeycomb-shaped heat storage material 24 is separated and placed in the lower part of the decomposition vessel 10 on the upstream side of the flow direction of ammonia NH3 introduced from the inlet 11. The catalyst pellets 21a are held on a holding protrusion 32 protruding from the inner circumference of the decomposition vessel 10, and a first catalyst layer 20a is provided on the first heat storage body 23a, in which the pellet-shaped catalyst 21a is stacked to an appropriate thickness. A second heat storage body 23b formed of a honeycomb-shaped heat storage material 24 is provided on the first catalyst layer 20a, a second catalyst layer 20b is provided on the second heat storage body 23b, in which the pellet-shaped catalyst 21a is stacked to an appropriate thickness. A third heat storage body 23c formed of a honeycomb-shaped heat storage material 24 is provided on the second catalyst layer 20b.

[0042] At this time, the size of the honeycomb mesh of the honeycomb-shaped heat storage material 24 is set smaller than the minimum dimension of the pellet-shaped catalyst 21a so that the pellet-shaped catalyst 21a does not fall out of the mesh holes.

[0043] Also in the ammonia decomposition apparatus according to the second embodiment, a heating device 40 consisting of a heater for heating the inside of the decomposition vessel 10 is provided on the outer periphery of the decomposition vessel 10, and a heat insulator 41 is provided on the outer periphery of the heating device 40 so that the heat generated by the heating device 40 is not dissipated to the outside, thereby efficiently heating each of the heat storage bodies 23 (23a to 23c) and each of the catalyst layers 20 (20a, 20b) provided in the decomposition vessel 10.

[0044] In the ammonia decomposition apparatus according to the second embodiment, ammonia NH3 is introduced into the decomposition vessel 10 through the inlet 11 provided at the bottom of the decomposition vessel 10 while the inside of the decomposition vessel 10 is heated by the heating device 40. The introduced ammonia NH3 is guided through the first heat storage body 23a, the first catalytic layer 20a, the second heat storage body 23b, the second catalytic layer 20b, and the third heat storage body 23c in this order within the decomposition vessel 10, and is decomposed into hydrogen H2 and nitrogen N2 while being heated. The ammonia NH3 is then taken out from the outlet 12 provided at the top of the decomposition vessel 10.

[0045] Here, when the heating device 40 provided on the outer periphery of the decomposition vessel 10 heats the heat storage bodies 23 (23a to 23c) and the catalyst layers 20 (20a, 20b) provided in the decomposition vessel 10 as described above, the ammonia NH3 introduced into the decomposition vessel 10 from the inlet 11 is heated by the heat stored in the first heat storage body 23a and guided to the first catalyst layer 20a, and is converted into hydrogen H2 and nitrogen H3 by the catalyst 21a in the heated first catalyst layer 20a. Ammonia NH3 is decomposed into hydrogen H2 and nitrogen N2, and the ammonia NH3 is heated by the heat stored in the second heat storage body 23b and introduced to the second catalytic layer 20b, where it is decomposed into hydrogen H2 and nitrogen N2 by the catalyst 21a in the heated second catalytic layer 20b. The hydrogen H2 and nitrogen N2 thus decomposed are introduced to the third heat storage body 23c, heated by the heat stored in the third heat storage body 23c, and taken out from the outlet 12.

[0046] Then, while the inside of the decomposition vessel 10 is heated by the heating device 40 as described above, ammonia NH3 introduced from the inlet 11 at the bottom of the decomposition vessel 10 is guided in the order of the first heat storage body 23a, the first catalyst layer 20a, the second heat storage body 23b, the second catalyst layer 20b, and the third heat storage body 23c, and heated while being decomposed into hydrogen H2 and nitrogen N2. By using the heat storage bodies 23a, 23b, and 23c, a higher temperature is maintained than if the space portion 22 was simply left open, and by sandwiching the catalyst layers 20a, 20b from above and below with the high-temperature heat storage bodies 23a, 23b, and 23c, the entire catalyst layers 20a, 20b are sufficiently heated and each catalyst 21a is activated, and the ammonia NH3 can be decomposed more efficiently into hydrogen H2 and nitrogen N2 and taken out from the outlet 12.

[0047] Furthermore, by heating the hydrogen H2 and nitrogen N2 decomposed as described above in the third heat storage body 23c and extracting them from the outlet 12, the hydrogen H2 can be extracted at a high temperature and can be easily used as fuel.

[0048] Here, in the ammonia decomposition apparatus according to the second embodiment, a honeycomb-shaped heat storage material 24a is used as the heat storage material 24 in the heat storage body 23, and a pellet-shaped catalyst 21a is used as the catalyst 21 in the catalyst layer 20. However, the heat storage material 24 in the heat storage body 23 and the catalyst 21 in the catalyst layer 20 used are not limited to these.

[0049] For example, in the second modification shown in FIG. 4, ball-shaped heat storage materials 24b are used as the heat storage material 24 in the heat storage body 23, and a gas-permeable holding member 31 such as a grating that holds the ball-shaped heat storage materials 24b so as not to spill out is provided above the inlet 11 for introducing ammonia NH3 into the decomposition vessel 10, and the ball-shaped heat storage materials 24b are stacked on the holding member 31 to an appropriate thickness to provide a first heat storage body 23a, and pellets are placed on the first heat storage body 23a. The first catalyst layer 20a is provided by stacking the pellet-shaped catalyst 21a to an appropriate thickness, the second heat storage body 23b is provided on the first catalyst layer 20a by stacking the ball-shaped heat storage material 24b to an appropriate thickness, the second catalyst layer 20b is provided on the second heat storage body 23b by stacking the pellet-shaped catalyst 21a to an appropriate thickness, and the third heat storage body 23c is provided on the second catalyst layer 20b by stacking the ball-shaped heat storage material 24b to an appropriate thickness.

[0050] Here, also in the modified example 2 shown in FIG. 4, a heating device 40 consisting of a heater for heating the inside of the decomposition vessel 10 is provided on the outer periphery of the decomposition vessel 10, and a heat insulator 41 is provided on the outer periphery of the heating device 40 so that the heat generated by the heating device 40 is not dissipated to the outside, thereby efficiently heating each of the heat storage bodies 23 (23a to 23c) and each of the catalyst layers 20 (20a, 20b) provided in the decomposition vessel 10.

[0051] In the ammonia decomposition apparatus according to the second modified example, similarly to the ammonia decomposition apparatus according to the second embodiment, ammonia NH3 is introduced into the decomposition vessel 10 from the inlet 11 provided at the bottom of the decomposition vessel 10 while the inside of the decomposition vessel 10 is heated by the heating device 40, and the introduced ammonia NH3 is guided in this order through the first heat storage body 23a, the first catalytic layer 20a, the second heat storage body 23b, the second catalytic layer 20b, and the third heat storage body 23c in the decomposition vessel 10, and is decomposed into hydrogen H2 and nitrogen N2 while being heated, and is taken out from the outlet 12 provided at the top of the decomposition vessel 10.

[0052] Here, when the heating device 40 provided on the outer periphery of the decomposition vessel 10 heats the heat storage bodies 23 (23a-23c) and the catalyst layers 20 (20a, 20b) provided in the decomposition vessel 10 as described above, the ammonia NH3 introduced from the inlet 11 is heated by the heat stored in the first heat storage body 23a and introduced to the first catalyst layer 20a, where it is decomposed into hydrogen H2 and nitrogen N2 in the heated first catalyst layer 20a, and the ammonia NH3 is heated by the heat stored in the second heat storage body 23b and introduced to the second catalyst layer 20b, where it is decomposed into hydrogen H2 and nitrogen N2 in the heated second catalyst layer 20b, and the hydrogen H2 and nitrogen N2 thus decomposed are introduced to the third heat storage body 23c, where it is heated by the heat stored in the third heat storage body 23c, and taken out from the outlet 12.

[0053] In the ammonia decomposition apparatus of the second modified example, the ball-shaped heat storage material 24b is used, and the heat storage material 24b has horizontal air permeability. Therefore, the heat from the heating device 40 can be more easily transmitted to the center of each catalyst layer 20a, 20b than the honeycomb-shaped heat storage material 24a used in the ammonia decomposition apparatus of the second embodiment. As a result, the ammonia NH3 introduced into the decomposition vessel 10 from the inlet 11 as described above is more efficiently decomposed into hydrogen H2 and nitrogen N2 in the decomposition vessel 10 and can be taken out from the outlet 12. At the same time, the decomposed hydrogen H2 and nitrogen N2 are heated in the third heat storage body 23c and taken out from the outlet 12. The hydrogen H2 can be taken out at a high temperature and can be easily used as fuel.

[0054] In the above-mentioned embodiment 2 and modified example 2, the three heat storage bodies 23 (23a to 23c) and two catalyst layers 20 (20a, 20b) are provided in the decomposition vessel 10. However, the number of heat storage bodies 23 and catalyst layers 20 provided in the decomposition vessel 10 is not limited, and the catalyst layers 20 and the heat storage bodies 23 may be alternated to provide even more catalyst layers 20 and heat storage bodies 23.

[0055] In addition, in the above-mentioned second embodiment and second modified example, the inlet 11 is provided at the bottom of the decomposition vessel 10 while the outlet 12 is provided at the top of the decomposition vessel 10. However, it is also possible to provide the inlet 11 at the top of the decomposition vessel 10 while providing the outlet 12 at the bottom of the decomposition vessel 10, and introduce ammonia NH3 into the decomposition vessel 10 from the inlet 11 at the top of the decomposition vessel 10, decompose it into hydrogen H2 and nitrogen N2 in the decomposition vessel 10, and take it out from the outlet 12 at the bottom of the decomposition vessel 10.

[0056] Furthermore, in the above-mentioned embodiment 2 and modified example 2, the inlet 11 and the outlet 12 are provided at the upper or lower part of the decomposition vessel 10, and multiple catalyst layers 20 and heat storage bodies 23 are provided in the decomposition vessel 10 by stacking them in the vertical direction. However, the present invention is not limited to this. Although not shown, the decomposition vessel 10 can be laid horizontally, and the inlet 11 and the outlet 12 can be provided on both sides of the decomposition vessel 10 in the horizontal direction, and multiple catalyst layers 20 and heat storage bodies 23 can be provided side by side in the decomposition vessel 10. [Explanation of symbols]

[0057] 10: Decomposition vessel 11: Entrance 12: Extraction port 20, 20a~20c: Catalyst layer 21, 21a, 21b: catalyst 22, 22a, 22b: Space part 23, 23a~23c: Heat storage body 24, 24a, 24b: Heat storage material 31: Retaining member 32: Holding protrusion 40: Heating device 41: Insulation H2: Hydrogen N2: Nitrogen NH3: Ammonia

Claims

1. An ammonia decomposition apparatus for decomposing ammonia into hydrogen and nitrogen in a decomposition vessel, the apparatus comprising: a catalytic layer using a catalyst for decomposing ammonia into hydrogen and nitrogen, the catalytic layer being provided in a plurality of stages in the decomposition vessel at required intervals in the flow direction of ammonia flowing in the decomposition vessel; and a heating device for heating the inside of the decomposition vessel.

2. 2. The ammonia decomposition apparatus according to claim 1, wherein the heating device is provided on the outer periphery of the decomposition vessel, and a heat insulator is provided on the outer periphery of the heating device.

3. 2. The ammonia decomposition apparatus according to claim 1, wherein, when catalyst layers are provided in a plurality of stages at required intervals in the direction of ammonia flow in the decomposition vessel, the catalyst layers are provided at required intervals in the vertical direction in the decomposition vessel.

4. The ammonia decomposition apparatus according to any one of claims 1 to 3, wherein when catalyst layers are provided in a plurality of stages at required intervals in the flow direction of ammonia in the decomposition vessel, a holding means for holding the catalyst layers is provided in the decomposition vessel, and a space is provided between the catalyst layers.

5. The ammonia decomposition apparatus according to any one of claims 1 to 3, wherein, when catalyst layers are provided in a plurality of stages at required intervals in the flow direction of ammonia in the decomposition vessel, a heat storage body having gas permeability is provided between the catalyst layers.

6. 6. An ammonia decomposition apparatus according to claim 5, wherein a heat storage body having gas permeability is provided on both sides of said catalyst layer in the direction of ammonia flow.

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