Catalyst device

Abstract

The utility model relates to a catalyst device. The technical disclosed in the specification solves the problem of inhibiting the deviation of the decomposition of raw material gas from the upstream to the downstream of the flow path in the catalyst device for decomposing raw material gas into reaction gas. The catalyst device (1) for decomposing raw material gas into reaction gas has a flow path (3) and a catalyst (10). The flow path (3) includes a constant cross-section region (5) with a substantially constant cross-sectional area. The catalyst (10) is granular and is housed in the constant cross-section region (5). By passing through the catalyst (10), the raw material gas is decomposed into reaction gas, and the total number of gas molecules increases. The catalyst (10) has a first average particle size (12a) in the upstream region (13) of the constant cross-section region (5). The catalyst (10) has a second average particle size (12c) larger than the first average particle size (12a) in the downstream region (15) downstream of the upstream region (13).

Description

Technical Field

[0001] This utility model relates to a catalyst device for decomposing raw material gas into reaction gas. Background Technology

[0002] Patent Document 1 discloses a catalyst structure for the decomposition of ammonia to produce hydrogen. Fine metal particles are used as the catalyst for ammonia decomposition. The catalyst structure is constructed by loading the catalyst into the interior of a porous support of a zeolite-type compound. Ammonia decomposes into hydrogen and nitrogen. The hydrogen contained in the hydrogen-nitrogen mixture is used as fuel for a fuel cell.

[0003] The catalyst is configured as a catalyst layer in a flow path through which the feed gas and the generated gas mixture flow. Considering the thermal efficiency of heating the catalyst layer from the outside of the flow path using a heater and the compactness of the catalyst unit, a substantially constant cross-sectional area of ​​the flow path from upstream to downstream is desirable. However, the total number of molecules in the feed gas differs from the total number of molecules in the generated gas mixture. Therefore, in conventional catalyst units with a substantially constant cross-sectional area flow path, a pressure difference occurs from upstream to downstream. For example, the total number of molecules in the generated hydrogen and nitrogen mixture increases to twice the total number of molecules in the ammonia feed gas. Consequently, the pressure is higher in the downstream region of the flow path than in the upstream region. Due to this pressure difference, the decomposition of the feed gas also deviates between the upstream and downstream regions. This can potentially lead to a decrease in the efficiency of feed gas decomposition and a reduction in the amount of reactant gas generated due to incomplete decomposition of the feed gas.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: International Publication No. 2018 / 221701 Utility Model Content

[0007] Problems to be solved by utility models

[0008] The problem to be solved by the technology disclosed in this specification is to suppress the deviation of the decomposition of the feed gas from upstream to downstream in a catalyst device for decomposing feed gas into reactant gas.

[0009] Solution for solving the problem

[0010] According to one technical solution of this utility model, a catalyst device for decomposing a raw material gas into a reactant gas has a flow path and a catalyst. The flow path includes a constant cross-sectional area region with an approximately constant cross-sectional area. The catalyst is granular and contained within the constant cross-sectional area. As the raw material gas passes through the catalyst, it is decomposed into the reactant gas, increasing the total number of gas molecules. The catalyst has a first average particle size in the upstream region of the constant cross-sectional area. The catalyst has a second average particle size, larger than the first average particle size, in the downstream region.

[0011] Therefore, a catalyst with a first average particle size is placed in the upstream region of a constant cross-sectional region where the proportion of feed gas is high and the proportion of reactant gas is low. A catalyst with a second average particle size is placed in the downstream region of a constant cross-sectional region where the proportion of feed gas is low and the proportion of reactant gas is high. As a result, the average void area in the cross-section is larger in the downstream region compared to the upstream region. The higher the proportion of reactant gas in a region, the greater the total number of molecules of feed gas and reactant gas combined. By making the void area in the cross-section larger in the downstream region where the proportion of reactant gas is high than in the upstream region, the pressure increase in the downstream region relative to the upstream region can be suppressed. This suppresses the pressure deviation from upstream to downstream of the flow path and also suppresses the deviation of feed gas decomposition from upstream to downstream of the flow path.

[0012] According to another technical solution of this utility model, the catalyst has the minimum average particle size in the upstream region of the inlet containing the constant cross-section region. The catalyst has the maximum average particle size in the downstream region of the outlet containing the constant cross-section region. The catalyst has an intermediate average particle size in the midstream region between the upstream and downstream regions, which is larger than the minimum average particle size but smaller than the maximum average particle size.

[0013] Therefore, the average particle size of the catalyst in the midstream region is made larger than the minimum average particle size in the upstream region. Consequently, the average void area in the cross-section of the midstream region of the constant cross-section is larger than that in the upstream region. The maximum average particle size of the catalyst in the downstream region is made larger than the average particle size in the midstream region. Consequently, the average void area in the cross-section of the downstream region of the constant cross-section is larger than that in the midstream region. This suppresses pressure increases in the midstream region relative to the upstream region, and also suppresses pressure increases in the downstream region relative to the midstream region. Therefore, pressure deviations and deviations in the decomposition of the feed gas can be suppressed between the upstream, midstream, and downstream regions of the flow path.

[0014] According to another technical solution of this utility model, the average particle size of the catalyst gradually increases from upstream to downstream along the entire length of the constant cross-sectional region. Therefore, as the proportion of reactant gases increases from the inlet to the outlet of the constant cross-sectional region, the average particle size of the catalyst gradually increases. This allows for more efficient suppression of pressure deviations and deviations in the decomposition of the feed gas along the entire length of the constant cross-sectional region.

[0015] According to another technical solution of this utility model, the constant cross-section region has a first average void area in the upstream region. The constant cross-section region has a second average void area that is larger than the first average void area in the downstream region. Therefore, granular catalysts are disposed in the upstream and downstream regions respectively, such that the second average void area in the downstream region of the constant cross-section region is greater than the first average void area in the upstream region. This allows for more reliable suppression of pressure deviations between the upstream and downstream regions of the constant cross-section region.

[0016] According to another technical solution of this utility model, the average void area along a predetermined length of the constant cross-sectional region gradually increases from upstream to downstream along the entire length of the constant cross-sectional region. Therefore, as the proportion of reactant gas increases from the inlet to the outlet of the constant cross-sectional region, the average void area gradually increases. Consequently, pressure deviations can be suppressed more reliably and efficiently along the entire length of the constant cross-sectional region.

[0017] According to another technical solution of this utility model, the raw material gas is ammonia. Therefore, even when the total number of reactant gases composed of hydrogen and nitrogen is increased to twice the total number of ammonia molecules relative to the total number of ammonia molecules in the raw material gas, it is possible to suppress the deviation of pressure from upstream to downstream of the flow path and the deviation of decomposition of the raw material gas from upstream to downstream of the flow path. Attached Figure Description

[0018] Figure 1 This is a block diagram of a fuel cell system equipped with the catalyst device of this utility model.

[0019] Figure 2 This is a longitudinal sectional view that schematically represents the catalyst apparatus of the first embodiment.

[0020] Figure 3 It is a diagram showing the cross-sections of the upstream, midstream, and downstream regions of the catalyst unit.

[0021] Figure 4 It is a graph showing the number of molecules of raw material gas and reactant gas from upstream to downstream.

[0022] Figure 5 This is a schematic longitudinal sectional view of the catalyst apparatus according to the second embodiment.

[0023] Figure 6This is a longitudinal sectional view that schematically represents the catalyst apparatus of the third embodiment.

[0024] Figure 7 This is a longitudinal sectional view that schematically represents the catalyst apparatus of the fourth embodiment.

[0025] Figure 8 This is a longitudinal sectional view that schematically represents the catalyst apparatus of the fifth embodiment.

[0026] Figure 9 This is a longitudinal sectional view that schematically represents the catalyst apparatus of the sixth embodiment.

[0027] Figure 10 This is a longitudinal sectional view that schematically represents the catalyst apparatus of the seventh embodiment.

[0028] Explanation of reference numerals in the attached figures

[0029] 1. Catalyst device (first embodiment); 2. Shell; 3. Flow path; 3a. Raw material gas inlet; 3b. Reaction gas outlet; 4. Heater; 5. Constant cross-section region (catalyst layer); 5a. Inlet; 5b. Outlet; 10. Catalyst; 10a, 10b, 10c, 10d. Particle size; 11. Void; 12. Average particle size; 12a. Uppermost average particle size (first average particle size, minimum average particle size); 12b. Midstream average particle size (first average particle size, second average particle size, intermediate average particle size); 12c. Lowermost average particle size (second average particle size, maximum average particle size); 13. Uppermost region (upstream region); 14. Midstream region (upstream region, downstream region); 15. Lowermost region 20. Fuel cell system; 21. Ammonia storage tank; 22. Adsorption device; 23. Fuel cell; 30. Catalyst device (second embodiment); 31. Average particle size; 31a. Uppermost average particle size (first average particle size, minimum average particle size); 31b. Middle and uppermost average particle size (first average particle size, second average particle size, intermediate average particle size); 31c. Middle and lowermost average particle size (first average particle size, second average particle size, intermediate average particle size); 31d. Lowermost average particle size (second average particle size, maximum average particle size); 32. Uppermost region (upstream region); 33. Middle and uppermost region (upstream region, downstream region); 34. Middle and lowermost region (upstream region, downstream region); 35. Lowermost region (downstream region, downstream region); 40. Catalyst device (third embodiment); 41. Average particle size; 41a. Uppermost average particle size (first average particle size, minimum average particle size); 41b. Midstream average particle size (first average particle size, second average particle size, intermediate average particle size); 41c. Lowermost average particle size (second average particle size, maximum average particle size); 42. Lowermost region (upstream region); 43. Midstream region (upstream region, downstream region); 44. Lowermost region (downstream region); 50. Catalyst device (fourth embodiment); 51. Average particle size; 51a. Uppermost average particle size (first average particle size, minimum average particle size); 51b. Midstream average particle size (first average particle size, second average particle size, intermediate average particle size); 51c, the most downstream average particle size (second average particle size, maximum average particle size); 52, the most upstream region (upstream region); 53, the midstream region (upstream region, downstream region); 54, the most downstream region (downstream region); 60, catalyst device (fifth embodiment); 61, average particle size; 61a, the most upstream average particle size (first average particle size, minimum average particle size); 61b, the mid-upstream average particle size (first average particle size, minimum average particle size); 61c, the most downstream average particle size (second average particle size, maximum average particle size); 62, the most upstream region (upstream region); 63, the midstream region (upstream region); 64, the most downstream region (downstream region); 70, catalyst device (sixth embodiment);71. Average particle size; 71a. Uppermost average particle size (first average particle size); 71b. Middle-upper average particle size (first average particle size, second average particle size); 71c. Middle-lower average particle size (first average particle size, second average particle size); 71d. Middle-lower average particle size (first average particle size, second average particle size); 71e. Lowermost average particle size (second average particle size); 72. Uppermost region (upper region); 73. Middle-upper region (upper region, downstream region); 74. Middle region (upper region, downstream region); 75. Middle-lower region (upper region, downstream region); 76. Lowermost region (downstream region); 80. Catalyst device (seventh embodiment) 81. Average particle size; 81a. Uppermost average particle size (first average particle size); 81b. Middle average particle size (second average particle size); 81c. Lowermost average particle size; 82. Uppermost region (upper region); 83. Middle region (upper region); 84. Lowermost region (downstream region). Detailed Implementation

[0030] The following is based on Figures 1-4 The first embodiment of the catalyst device of this utility model will be described. The same reference numerals in the description refer to the same elements having the same function, and will not be described repeatedly. For example... Figure 1 As shown, catalyst unit 1 is disposed in fuel cell system 20. Fuel cell system 20 has an ammonia storage tank 21 upstream of catalyst unit 1. Fuel cell system 20 has an adsorption unit 22 downstream of catalyst unit 1, and a fuel cell (FC) 23 is further disposed downstream.

[0031] like Figure 1 As shown, ammonia (NH3) is introduced into the catalyst unit 1 from the ammonia storage tank 21 as a feed gas. In the catalyst unit 1, ammonia is decomposed into hydrogen (H2) and nitrogen (N2), generating a reaction gas containing hydrogen and nitrogen. A mixture of the reaction gas and trace amounts of undecomposed ammonia is discharged from the catalyst unit 1 to the adsorption unit 22. The adsorption unit 22 adsorbs the ammonia contained in the mixture. The purified gas, from which ammonia has been removed from the mixture, is introduced into the fuel cell 23. The fuel cell 23 uses the hydrogen contained in the purified gas as fuel to generate electricity.

[0032] like Figure 2 As shown, the catalyst device 1 has a generally cylindrical shell 2. A flow path 3 is provided inside the shell 2. A feed gas inlet 3a, communicating with the flow path 3, is provided at the upstream end of the shell 2. Ammonia, as the feed gas, is introduced from an upstream ammonia storage tank 21 (see reference 2) via the feed gas inlet 3a. Figure 1The catalyst is introduced into the flow path 3 of the catalyst device 1. A reaction gas outlet 3b, communicating with the flow path 3, is provided at the downstream end of the housing 2. A mixed gas containing hydrogen and nitrogen as reaction gases flows from the flow path 3 to the downstream adsorption device 22 (see reference 22) via the reaction gas outlet 3b. Figure 1 )discharge.

[0033] like Figure 2 As shown, most of the flow path 3 is a constant cross-sectional area 5 with a substantially constant cross-sectional area orthogonal to the flow direction. From the inlet 5a at the upstream end of the constant cross-sectional area 5 to the outlet 5b at the downstream end, the cross-sectional area remains substantially constant. In this invention, "substantially constant cross-sectional area" means that, relative to the minimum cross-sectional area of ​​the constant cross-sectional area 5, the maximum cross-sectional area is, for example, less than +10%, less than +5%, or less than +3%. A heater 4 is provided on the radially outer side of the housing 2. The heater 4 heats the constant cross-sectional area 5 to substantially the same degree. The radially outer periphery of the heater 4 is covered with an insulating material (not shown).

[0034] like Figure 2 As shown, the constant cross-section region 5 is a catalyst layer housing multiple catalysts 10. The catalysts 10 are generally spherical granules or blocks. Multiple catalysts 10 are configured with approximately the same shape. Voids 11 are formed between the multiple catalysts 10. The catalysts 10 are formed by mixing and sintering fine metal particles, which function as catalysts themselves, with a support. Fine metal particles are exposed on the surface of the catalyst 10. The material of the fine metal particles, etc., can be, for example, at least one of ruthenium, nickel, cobalt, and palladium, but is not limited to these; other metals, alloys, etc., can also be used. Furthermore, for ease of observation of the figures, the figures show catalysts 10 filled only in a localized area of ​​the constant cross-section region 5, but in reality, catalysts 10 are filled throughout the entire length of the constant cross-section region 5. Additionally, the sizes of the catalysts 10 in the figures roughly represent the relative size relationships of the multiple catalysts 10, and do not specifically limit, for example, the size ratio of each catalyst 10, nor the size ratio of the catalyst 10 to the shell 2.

[0035] like Figure 2As shown, the constant cross-section region 5 includes an upstream region 13 containing an inlet 5a, a downstream region 15 containing an outlet 5b, and a midstream region 14 between the upstream region 13 and the downstream region 15. The upstream region 13 is filled with catalyst 10 with a particle size of 10a. The average particle size 12 of the catalyst 10 in the upstream region 13 is the upstream average particle size 12a, which has approximately the same diameter as particle size 10a. The midstream region 14 is filled with catalyst 10 with a particle size of 10b. Particle size 10b is larger than particle size 10a. The average particle size 12 of the catalyst 10 in the midstream region 14 is the midstream average particle size 12b, which has approximately the same diameter as particle size 10b and is larger than the upstream average particle size 12a. The downstream region 15 is filled with catalyst 10 with a particle size of 10c. Particle size 10c is larger than particle size 10b. The average particle size 12 of the catalyst 10 in the downstream region 15 is approximately the same diameter as the particle size 10c and larger than the average particle size 12b in the midstream region.

[0036] like Figure 2 As shown, the second average particle size in the downstream region is larger than the first average particle size in the upstream region. When the upstream region 13 is designated as the upstream region and the downstream region 15 as the downstream region, the downstream average particle size 12c, which is the second average particle size, is larger than the upstream average particle size 12a, which is the first average particle size. When the upstream region 13 is designated as the upstream region and the midstream region 14 as the downstream region, the midstream average particle size 12b, which is the second average particle size, is larger than the upstream average particle size 12a, which is the first average particle size. When the midstream region 14 is designated as the upstream region and the downstream region 15 as the downstream region, the downstream average particle size 12c, which is the second average particle size, is larger than the midstream average particle size 12b, which is the first average particle size.

[0037] like Figure 2 As shown, the average particle size 12 of catalyst 10 gradually increases from upstream to downstream in the upstream region 13, midstream region 14, and downstream region 15, with the average particle size 12a in the upstream region, 12b in the midstream region, and 12c in the downstream region. The upstream average particle size 12a in the upstream region 13 is the smallest among the average particle sizes 12 of each flow area in the constant cross-section region 5. The downstream average particle size 12c in the downstream region 15 is the largest among the average particle sizes 12 of each flow area in the constant cross-section region 5. The midstream average particle size 12b in the midstream region 14 is an intermediate average particle size that is larger than the upstream average particle size 12a (which has the smallest average particle size) and smaller than the downstream average particle size 12c (which has the largest average particle size).

[0038] like Figure 3As shown, the average void area obtained by averaging the area of ​​the voids 11 in each cross-section of the upstream region 13 across the entire upstream region 13 is approximately the same size as the area of ​​the voids 11 in the cross-section at a specified position in the upstream region 13. Similarly, the average void area obtained by averaging the area of ​​the voids 11 in each cross-section of the midstream region 14 across the entire midstream region 14 is approximately the same size as the area of ​​the voids 11 in the cross-section at a specified position in the midstream region 14. Likewise, the average void area obtained by averaging the area of ​​the voids 11 in each cross-section of the downstream region 15 across the entire downstream region 15 is approximately the same size as the area of ​​the voids 11 in the cross-section at a specified position in the downstream region 15. The average void area of ​​each region in the constant cross-section region 5 gradually increases from upstream to downstream, from the upstream region 13, midstream region 14, to the downstream region 15.

[0039] like Figure 3 As shown, the second average void area in the downstream region is greater than the first average void area in the upstream region. When the upstream region 13 is designated as the upstream region and the downstream region 15 as the downstream region, the second average void area in the downstream region 15 is larger than the first average void area in the upstream region 13. When the upstream region 13 is designated as the upstream region and the midstream region 14 as the downstream region, the second average void area in the midstream region 14 is larger than the first average void area in the upstream region 13. When the midstream region 14 is designated as the upstream region and the downstream region 15 as the downstream region, the second average void area in the downstream region 15 is larger than the first average void area in the midstream region 14.

[0040] Ammonia is decomposed into hydrogen and nitrogen as shown in the following chemical reaction (1). Figure 4 As shown, when the total number of ammonia molecules in the raw material gas is set to n, and all ammonia is decomposed into hydrogen and nitrogen, the total number of molecules in the reaction gas formed by the mixture of hydrogen and nitrogen increases to 2n. Therefore, the process moves towards the constant cross-section region 5 (refer to...). Figure 2 Downstream of the reaction gas, the greater the total number of molecules per unit volume of the raw material gas and reactant gas combined. By increasing the void 11 downstream of the constant cross-section region 5 compared to the upstream, the pressure rise caused by the increase in the total number of molecules can be suppressed.

[0041] 2NH3→3H2+N2……(1)

[0042] As described above, the catalyst device 1 that decomposes the raw material gas into the reactant gas is as follows: Figure 2The circuit has a flow path 3 and a catalyst 10 as shown. The flow path 3 includes a constant cross-sectional area 5 with a substantially constant cross-sectional area. The catalyst 10 is granular and contained within the constant cross-sectional area 5. As the feed gas passes through the catalyst 10, it is decomposed into reactant gases, increasing the total number of gas molecules. The catalyst 10 has a first average particle size 12a in the upstream region (upstream region) 13 of the constant cross-sectional area 5. The catalyst 10 has a second average particle size 12c, which is larger than the first average particle size 12a, in the downstream region (downstream region) 15, which is further downstream of the upstream region 13.

[0043] Therefore, a catalyst 10 with a first average particle size of 12a is provided in the upstream region 13 of the constant cross-section region 5, where the proportion of raw gas is high and the proportion of reactant gas is low. A catalyst 10 with a second average particle size of 12c is provided in the downstream region 15 of the constant cross-section region 5, where the proportion of raw gas is low and the proportion of reactant gas is high. As a result, the average void area in the cross-section of the downstream region 15 of the constant cross-section region 5 is larger than that of the upstream region 13. The higher the proportion of reactant gas in the region, the greater the total number of molecules of raw gas and reactant gas combined. By making the void area in the cross-section of the downstream region 15, where the proportion of reactant gas is high, larger than that of the upstream region 13, it is possible to suppress the increase in pressure in the downstream region 15 relative to the upstream region 13. As a result, it is possible to suppress the deviation of pressure from upstream to downstream of the flow path 3, and to suppress the deviation of raw gas decomposition from upstream to downstream of the flow path 3.

[0044] like Figure 2 As shown, catalyst 10 has a minimum average particle size 12a in the upstream region 13 of the inlet 5a, which includes the constant cross-section region 5. Catalyst 10 has a maximum average particle size 12c in the downstream region 15 of the outlet 5b, which includes the constant cross-section region 5. Catalyst 10 has an intermediate average particle size 12b in the midstream region 14 between the upstream region 13 and the downstream region 15, which is larger than the minimum average particle size 12a and smaller than the maximum average particle size 12c.

[0045] Therefore, the average particle size 12b of the catalyst 10 in the midstream region 14 is made larger than the minimum average particle size 12a of the upstream region 13. Consequently, the average void area in the cross-section of the midstream region 14 of the constant cross-section region 5 is larger than that of the upstream region 13. The maximum average particle size 12c of the catalyst 10 in the downstream region 15 is made larger than the average particle size 12b of the midstream region 14. Consequently, the average void area in the cross-section of the downstream region 15 of the constant cross-section region 5 is larger than that of the midstream region 14. This suppresses the increase in pressure in the midstream region 14 relative to the upstream region 13, and also suppresses the increase in pressure in the downstream region 15 relative to the midstream region 14. Therefore, pressure deviations and deviations in the decomposition of the feed gas can be suppressed between the upstream region 13, the midstream region 14, and the downstream region 15 of the flow path 3.

[0046] like Figure 2 , Figure 3 As shown, the average particle size 12 of catalyst 10 gradually increases from upstream to downstream along the entire length of the constant cross-section region 5. Therefore, as the proportion of reactant gas increases from the inlet 5a to the outlet 5b of the constant cross-section region 5, the average particle size 12 of catalyst 10 gradually increases. Consequently, pressure deviations and deviations in the decomposition of feed gas can be suppressed more efficiently along the entire length of the constant cross-section region 5.

[0047] like Figure 2 , Figure 3 As shown, the constant cross-section region 5 has a first average void area in the upstream region 13. The constant cross-section region 5 has a second average void area in the downstream region 15 that is larger than the first average void area. Therefore, granular catalyst 10 is disposed in the upstream region 13 and the downstream region 15 such that the second average void area in the downstream region 15 of the constant cross-section region 5 is greater than the first average void area in the upstream region 13. As a result, pressure deviations in the upstream region 13 and the downstream region 15 of the constant cross-section region 5 can be suppressed more reliably.

[0048] like Figure 2 , Figure 3 As shown, the average void area along the specified length of the constant cross-section region 5 gradually increases from upstream to downstream. Therefore, as the proportion of reactant gas increases from the inlet 5a to the outlet 5b of the constant cross-section region 5, the average void area gradually increases. This allows for more reliable and efficient suppression of pressure deviations along the entire length of the constant cross-section region 5.

[0049] like Figure 4As shown, the feed gas is ammonia. Therefore, even when the total number of reactant gases composed of hydrogen and nitrogen increases to 2n, which is twice the total number of ammonia molecules in the feed gas, it is possible to suppress the deviation of pressure from upstream to downstream of flow path 3 and the deviation of feed gas decomposition from upstream to downstream of flow path 3.

[0050] The following is based on Figure 5 A second embodiment of the catalyst device of this utility model will be described. In the second embodiment, the constant cross-sectional region 5 of the catalyst device 30 sequentially comprises an upstream region 32, a mid-upstream region 33, a mid-downstream region 34, and a downstream region 35, replacing... Figure 2 The upstream region 32, the midstream region 14, and the downstream region 15 are shown. The upstream region 32 contains the inlet 5a of the constant cross-section region 5. The downstream region 35 contains the outlet 5b of the constant cross-section region 5. In the following description, only the parts that differ from the first embodiment will be described in detail.

[0051] like Figure 5 As shown, the upstream region 32 is filled with catalyst 10 with a particle size of 10a. The average particle size 31 of the catalyst 10 in the upstream region 32 is the upstream average particle size 31a, which is approximately the same diameter as the particle size 10a. The mid-upstream region 33 is filled with catalyst 10 of both particle sizes 10a and 10b. The catalyst 10 of particle size 10a and catalyst 10 of particle size 10b are mixed substantially uniformly within the mid-upstream region 33. In the following description, multiple sizes of catalysts are mixed substantially uniformly within the same region. The average particle size 31 of the catalyst 10 in the mid-upstream region 33 is the mid-upstream average particle size 31b, which is larger than the particle size 10a and the upstream average particle size 31a but smaller than the particle size 10b. The mid-downstream region 34 is filled with catalyst 10 of both particle sizes 10b and 10c. The average particle size 31 of the catalyst 10 in the mid-to-downstream region 34 is larger than the average particle size 31b of the mid-to-upstream region, larger than particle size 10b, and smaller than particle size 10c. The downstream region 35 is filled with catalyst 10 with a particle size of 10c. The average particle size 31 of the catalyst 10 in the downstream region 35 is approximately the same diameter as particle size 10c and larger than the average particle size 31c of the mid-to-downstream region, with a downstream average particle size 31d.

[0052] like Figure 5As shown, when the upstream region 32 is designated as the upstream region and the mid-upstream region 33, the mid-downstream region 34, or the downstream region 35 is designated as the downstream region, the mid-upstream average particle size 31b, the mid-downstream average particle size 31c, or the downstream average particle size 31d, which serves as the second average particle size, is larger than the upstream average particle size 31a, which serves as the first average particle size. When the mid-upstream region 33 is designated as the upstream region and the mid-downstream region 34 or the downstream region 35 is designated as the downstream region, the mid-downstream average particle size 31c or the downstream average particle size 31d, which serves as the second average particle size, is larger than the mid-upstream average particle size 31b, which serves as the first average particle size. When the mid-downstream region 34 is designated as the upstream region and the downstream region 35 is designated as the downstream region, the downstream average particle size 31d, which serves as the second average particle size, is larger than the mid-downstream average particle size 31c, which serves as the first average particle size.

[0053] like Figure 5 As shown, the average particle size 31 of catalyst 10 gradually increases from upstream to downstream with the following average particle size: upstream average particle size 31a, mid-upstream average particle size 31b, mid-downstream average particle size 31c, and downstream average particle size 31d. The upstream average particle size 31a is the smallest, and the downstream average particle size 31d is the largest. The mid-upstream average particle size 31b and the mid-downstream average particle size 31c are intermediate average particle sizes that are larger than the upstream average particle size 31a (which has the smallest average particle size) and smaller than the downstream average particle size 31d (which has the largest average particle size).

[0054] like Figure 5 As shown, the average void area of ​​each region in the constant cross-section region 5 gradually increases from upstream to downstream as the average particle size of each region increases, with the upstream region 32, the mid-upstream region 33, the mid-downstream region 34, and the downstream region 35. When the upstream region 32 is designated as the upstream region, and the mid-upstream region 33, the mid-downstream region 34, or the downstream region 35 is designated as the downstream region, the second average void area of ​​each downstream region is larger than the first average void area of ​​the upstream region 32. Similarly, when the mid-upstream region 33 is designated as the upstream region, and the mid-downstream region 34 or the downstream region 35 is designated as the downstream region, the second average void area of ​​each downstream region is larger than the first average void area of ​​the mid-upstream region 33. Finally, when the mid-downstream region 34 is designated as the upstream region, and the downstream region 35 is designated as the downstream region, the second average void area of ​​the downstream region 35 is larger than the first average void area of ​​the mid-downstream region 34.

[0055] The catalyst device 30 according to the second embodiment described above achieves the same effects as the first embodiment. For example, it can suppress pressure deviation from upstream to downstream of the flow path 3, and it can suppress deviation of feed gas decomposition from upstream to downstream of the flow path 3.

[0056] The following is based on Figure 6A third embodiment of the catalyst device of this utility model will be described. In the third embodiment, the constant cross-sectional region 5 of the catalyst device 40 sequentially comprises an upstream region 42, a midstream region 43, and a downstream region 44, replacing... Figure 2 The upstream region 42, the midstream region 14, and the downstream region 15 are shown. The upstream region 42 contains the inlet 5a of the constant cross-section region 5. The downstream region 44 contains the outlet 5b of the constant cross-section region 5. In the following description, only the parts that differ from the first embodiment will be described in detail.

[0057] like Figure 6 As shown, the upstream region 42 is filled with catalyst 10 of two sizes, 10a and 10b. The average particle size 41 of the catalyst 10 in the upstream region 42 is an upstream average particle size 41a that is larger than 10a but smaller than 10b. The midstream region 43 is filled with catalyst 10 of size 10b. The average particle size 41 of the catalyst 10 in the midstream region 43 is a midstream average particle size 41b that is approximately the same diameter as 10a but larger than the upstream average particle size 41a. The downstream region 44 is filled with catalyst 10 of two sizes, 10b and 10c. The average particle size 41 of the catalyst 10 in the downstream region 44 is a downstream average particle size 41c that is larger than both 10b and the midstream average particle size 41b but smaller than 10c.

[0058] like Figure 6 As shown, when the upstream region 42 is designated as the upstream region and either the midstream region 43 or the downstream region 44 is designated as the downstream region, the midstream average particle size 41b or the downstream average particle size 41c, which is the second average particle size, is larger than the upstream average particle size 41a, which is the first average particle size. When the midstream region 43 is designated as the upstream region and the downstream region 44 is designated as the downstream region, the downstream average particle size 41c, which is the second average particle size, is larger than the midstream average particle size 41b, which is the first average particle size. The average particle size 41 of the catalyst 10 gradually increases from upstream to downstream with the upstream average particle size 41a, the midstream average particle size 41b, and the downstream average particle size 41c. The upstream average particle size 41a is the smallest, and the downstream average particle size 41c is the largest. The midstream average particle size 41b is an intermediate average particle size that is larger than the upstream average particle size 41a, which is the smallest average particle size, and smaller than the downstream average particle size 41c, which is the largest average particle size.

[0059] like Figure 6As shown, the average void area of ​​each region in the constant cross-section region 5 gradually increases from upstream to downstream as the average particle size of each region increases, with the upstream region 42, the midstream region 43, and the downstream region 44. When the upstream region 42 is designated as the upstream region and either the midstream region 43 or the downstream region 44 is designated as the downstream region, the second average void area of ​​each downstream region is larger than the first average void area of ​​the upstream region 42. When the midstream region 43 is designated as the upstream region and the downstream region 44 is designated as the downstream region, the second average void area of ​​the downstream region 44 is larger than the first average void area of ​​the midstream region 43.

[0060] The catalyst device 40 according to the third embodiment described above achieves the same effects as the first embodiment. For example, it can suppress pressure deviation from upstream to downstream of the flow path 3, and it can suppress deviation of feed gas decomposition from upstream to downstream of the flow path 3.

[0061] The following is based on Figure 7 A fourth embodiment of the catalyst device of this invention will be described. In the fourth embodiment, the constant cross-sectional region 5 of the catalyst device 50 sequentially comprises an upstream region 52, a midstream region 53, and a downstream region 54, replacing... Figure 2 The upstream region 52, the midstream region 14, and the downstream region 15 are shown. The upstream region 52 contains the inlet 5a of the constant cross-section region 5. The downstream region 54 contains the outlet 5b of the constant cross-section region 5. In the following description, only the parts that differ from the first embodiment will be described in detail.

[0062] like Figure 7 As shown, the upstream region 52, midstream region 53, and downstream region 54 are all filled with catalyst 10 of two sizes: 10a and 10c. The proportion of catalyst 10 with a smaller diameter of 10a decreases from upstream to downstream in the upstream region 52, midstream region 53, and downstream region 54. The average particle size 51 of the catalyst 10 in the upstream region 52 is larger than 10a but smaller than 10c. The average particle size 51 of the catalyst 10 in the midstream region 53 is larger than 10a, larger than the upstream average particle size 51a, and smaller than 10c. The average particle size 51 of the catalyst 10 in the downstream region 54 is larger than 10a, larger than the midstream average particle size 51b, and smaller than 10c.

[0063] like Figure 7As shown, when the upstream region 52 is designated as the upstream region and either the midstream region 53 or the downstream region 54 is designated as the downstream region, the midstream average particle size 51b or the downstream average particle size 51c, which is the second average particle size, is larger than the upstream average particle size 51a, which is the first average particle size. When the midstream region 53 is designated as the upstream region and the downstream region 54 is designated as the downstream region, the downstream average particle size 51c, which is the second average particle size, is larger than the midstream average particle size 51b, which is the first average particle size. The average particle size 51 of the catalyst 10 gradually increases from upstream to downstream with the upstream average particle size 51a, the midstream average particle size 51b, and the downstream average particle size 51c. The upstream average particle size 51a is the smallest, and the downstream average particle size 51c is the largest. The midstream average particle size 51b is an intermediate average particle size that is larger than the upstream average particle size 51a, which is the smallest average particle size, and smaller than the downstream average particle size 51c, which is the largest average particle size.

[0064] like Figure 7 As shown, the average void area of ​​each region in the constant cross-section region 5 gradually increases from upstream to downstream as the average particle size of each region increases, starting with the upstream region 52, then the midstream region 53, and finally the downstream region 54. When the upstream region 52 is designated as the upstream region and either the midstream region 53 or the downstream region 54 is designated as the downstream region, the second average void area of ​​each downstream region is larger than the first average void area of ​​the upstream region 52. Similarly, when the midstream region 53 is designated as the upstream region and the downstream region 54 is designated as the downstream region, the second average void area of ​​the downstream region 54 is larger than the first average void area of ​​the midstream region 53.

[0065] The catalyst device 50 according to the fourth embodiment described above achieves the same effects as the first embodiment. For example, it can suppress pressure deviation from upstream to downstream of the flow path 3, and it can suppress decomposition deviation of the feed gas from upstream to downstream of the flow path 3.

[0066] The following is based on Figure 8 A fifth embodiment of the catalyst device of this invention will be described. In the fifth embodiment, the constant cross-sectional region 5 of the catalyst device 60 sequentially comprises an upstream region 62, a midstream region 63, and a downstream region 64, replacing... Figure 2 The upstream region 62, the midstream region 64, and the downstream region 65 are shown. The upstream region 62 contains the inlet 5a of the constant cross-section region 5. The downstream region 64 contains the outlet 5b of the constant cross-section region 5. In the following description, only the parts that differ from the first embodiment will be described in detail.

[0067] like Figure 8As shown, both the upstream region 62 and the midstream region 63 are filled with catalyst 10 with a particle size of 10a. The midstream region 63 is continuous with the upstream region 62 and can also be said to be contained within the upstream region 62. The average particle size 61 of the catalyst 10 in the upstream region 62 and the midstream region 63 is the upstream average particle size 61a and the midstream average particle size 61b, which are approximately the same diameter as the particle size 10a. The downstream region 64 is filled with catalyst 10 with a particle size of 10c. The average particle size 61 of the catalyst 10 in the downstream region 64 is the downstream average particle size 61c, which is approximately the same diameter as the particle size 10c and larger than the upstream average particle size 61a and the midstream average particle size 61b.

[0068] like Figure 8 As shown, when the upstream region 62 or the midstream region 63 is considered the upstream region and the downstream region 64 is considered the downstream region, the downstream average particle size 61c, which is the second average particle size, is larger than the upstream average particle size 61a or the midstream average particle size 61b, which is the first average particle size. The average particle size 61 of the catalyst 10, from upstream to downstream, has approximately the same diameter or increases in size for the upstream average particle size 61a, the midstream average particle size 61b, and the downstream average particle size 61c. The upstream average particle size 61a and the midstream average particle size 61b are the minimum average particle size, and the downstream average particle size 61c is the maximum average particle size.

[0069] like Figure 8 As shown, the average void area of ​​each region in the constant cross-section region 5 increases with the average particle size of each region, with the upstream region 62, the midstream region 63, and the downstream region 64 having approximately the same area or increasing from upstream to downstream. When the upstream region 62 or the midstream region 63 is designated as the upstream region and the downstream region 64 is designated as the downstream region, the second average void area of ​​the downstream region 64 is larger than the first average void area of ​​the upstream region 62 or the midstream region 63.

[0070] The catalyst device 60 according to the fifth embodiment described above achieves the same effects as the first embodiment. For example, it can suppress pressure deviation from upstream to downstream of the flow path 3, and it can suppress deviation of feed gas decomposition from upstream to downstream of the flow path 3.

[0071] The following is based on Figure 9 A sixth embodiment of the catalyst device of this invention will be described. In the sixth embodiment, the constant cross-sectional region 5 of the catalyst device 70, from upstream, sequentially comprises an upstream region 72, a mid-upstream region 73, a midstream region 74, a mid-downstream region 75, and a downstream region 76, instead of... Figure 2The upstream region 72, the midstream region 73, and the downstream region 74 are shown. The upstream region 72 contains the inlet 5a of the constant cross-section region 5. The downstream region 76 contains the outlet 5b of the constant cross-section region 5. In the following description, only the parts that differ from the first embodiment will be described in detail.

[0072] like Figure 9 As shown, the upstream region 72 is filled with catalyst 10 with a particle size of 10b. The average particle size 71 of the catalyst 10 in the upstream region 72 is the upstream average particle size 71a, which has a diameter approximately the same as that of particle size 10b. The mid-upstream region 73 is filled with catalyst 10 with a particle size of 10a. The average particle size 71 of the catalyst 10 in the mid-upstream region 73 is the mid-upstream average particle size 71b, which has a diameter approximately the same as that of particle size 10a. The midstream region 74 is filled with catalyst 10 with a particle size of 10b. The average particle size 71 of the catalyst 10 in the midstream region 74 is the midstream average particle size 71c, which has a diameter approximately the same as that of particle size 10b and is larger than the mid-upstream average particle size 71b. The mid-downstream region 75 is filled with catalyst 10 with a particle size of 10c. The average particle size 71 of the catalyst 10 in the mid-downstream region 75 is the mid-downstream average particle size 71d, which has a diameter approximately the same as that of particle size 10c and is larger than the midstream average particle size 71c. The downstream region 76 is filled with catalyst 10 with a particle size of 10d. The average particle size 71 of the catalyst 10 in the downstream region 76 is approximately the same diameter as the particle size 10d and larger than the average particle size 71d of the middle and downstream regions.

[0073] like Figure 9 As shown, when the upstream region 72 is designated as the upstream region and the mid-to-downstream region 75 or the downstream region 76 is designated as the downstream region, the mid-to-downstream average particle size 71d or the downstream average particle size 71e, which serves as the second average particle size, is larger than the upstream average particle size 71a, which serves as the first average particle size. When the mid-to-upstream region 73 is designated as the upstream region and the midstream region 74, the mid-to-downstream region 75, or the downstream region 76 is designated as the downstream region, the midstream average particle size 71c, the mid-to-downstream average particle size 71d, or the downstream average particle size 71e, which serves as the second average particle size, is larger than the mid-to-upstream average particle size 71b, which serves as the first average particle size. When the midstream region 74 is designated as the upstream region and the mid-to-downstream region 75 or the downstream region 76 is designated as the downstream region, the mid-to-downstream average particle size 71d or the downstream average particle size 71e, which serves as the second average particle size, is larger than the midstream average particle size 71c, which serves as the first average particle size. When the mid-to-downstream region 75 is designated as the upstream region and the downstream region 76 as the downstream region, the downstream average particle size 71e, which is the second average particle size, is larger than the mid-to-downstream average particle size 71d, which is the first average particle size.

[0074] like Figure 9As shown, the average particle size 71 of catalyst 10 gradually increases from the upstream region 73 toward the downstream region with the following average particle sizes: upstream average particle size 71b, midstream average particle size 71c, midstream average particle size 71d, and downstream average particle size 71e. The midstream average particle size 71d is an intermediate average particle size that is larger than the upstream average particle size 71a and smaller than the downstream average particle size 71e.

[0075] like Figure 9 As shown, the average void area of ​​each region in the constant cross-section region 5 gradually increases as the average particle size of each region increases from the upper-middle region 73 towards the downstream. When the uppermost region 72 is designated as the upstream region and either the middle-lower reaches region 75 or the lowermost region 76 is designated as the downstream region, the second average void area of ​​each downstream region is larger than the first average void area of ​​the uppermost region 72. Similarly, when the upper-middle region 73 is designated as the upstream region and either the middle reaches region 74, the middle-lower reaches region 75, or the lowermost region 76 is designated as the downstream region, the second average void area of ​​each downstream region is larger than the first average void area of ​​the upper-middle region 73. Likewise, when the middle reaches region 74 is designated as the upstream region and either the middle-lower reaches region 75 or the lowermost region 76 is designated as the downstream region, the second average void area of ​​each downstream region is larger than the first average void area of ​​the middle reaches region 74. Finally, when the middle-lower reaches region 75 is designated as the upstream region and the lowermost region 76 is designated as the downstream region, the second average void area of ​​the lowermost region 76 is larger than the first average void area of ​​the middle-lower reaches region 75.

[0076] The catalyst device 70 according to the sixth embodiment described above achieves the same effects as the first embodiment. For example, it can suppress pressure deviation from upstream to downstream of the flow path 3, and it can suppress decomposition deviation of the feed gas from upstream to downstream of the flow path 3.

[0077] The following is based on Figure 10 A seventh embodiment of the catalyst device of this invention will be described. In the seventh embodiment, the constant cross-sectional region 5 of the catalyst device 80 sequentially comprises an upstream region 82, a midstream region 83, and a downstream region 84, replacing... Figure 2 The upstream region 82, the midstream region 84, and the downstream region 85 are shown. The upstream region 82 includes the inlet 5a of the constant cross-section region 5. The downstream region 84 includes the outlet 5b of the constant cross-section region 5. In the following description, only the parts that differ from the first embodiment will be described in detail.

[0078] like Figure 10As shown, both the upstream region 82 and the downstream region 84 are filled with catalyst 10 with a particle size of 10a. The average particle size 81 of the catalyst 10 in the upstream region 82 and the downstream region 84 is the upstream average particle size 81a and the downstream average particle size 81c, which are approximately the same diameter as the particle size 10a. The midstream region 83 is filled with catalyst 10 with a particle size of 10c. The average particle size 81 of the catalyst 10 in the midstream region 83 is the midstream average particle size 81b, which is approximately the same diameter as the particle size 10c and is larger than the upstream average particle size 81a and the downstream average particle size 81c. When the upstream region 82 is designated as the upstream region and the midstream region 83 is designated as the downstream region, the midstream average particle size 81b, which is the second average particle size, is larger than the upstream average particle size 81a, which is the first average particle size. The average particle size 81 of the catalyst 10 increases from the upstream region 82 toward the midstream region 83 with the upstream average particle size 81a and the midstream average particle size 81b.

[0079] like Figure 10 As shown, the average void area of ​​each region in the constant cross-section region 5 increases as the average particle size increases from the upstream region 82 towards the midstream region 83. When the upstream region 82 is defined as the upstream region and the midstream region 83 as the downstream region, the second average void area of ​​the midstream region 83 is larger than the first average void area of ​​the upstream region 82.

[0080] The catalyst apparatus 80 according to the seventh embodiment described above achieves the same effects as the first embodiment. For example, it can suppress pressure deviation from upstream to downstream of the flow path 3, and it can suppress deviation of feed gas decomposition from upstream to downstream of the flow path 3.

[0081] The technology disclosed in this specification is not limited to the embodiments described above, and various modifications are possible. An example is a catalyst apparatus for decomposing ammonia. However, it is not limited to this and can be applied to all decompositions in which the total number of molecules increases as a result of the decomposition of a feed gas into a reactant gas. An example is the decomposition of ammonia in which the total number of molecules increases to twice its original value, but the rate of increase in the total number of molecules is not limited to this and can be less than twice or greater than twice its original value.

[0082] An example of a catalyst 10 is shown, in which fine metal particles are mixed with a support, thereby exposing the fine metal particles on the surface. Alternatively, fine metal particles may be coated onto the surface of the support. For example, the metal that functions as the catalyst body may be formed into particulate form and used as the catalyst. The shape of the catalyst 10 is illustrated as approximately spherical, but it is not limited to this. When the catalyst is non-spherical, the "particle size" may be replaced by, for example, the maximum length of the particulate catalyst, or the average of the maximum and minimum lengths.

[0083] The diameter and length of the constant cross-section region 5 are not limited to the illustrated case and can be appropriately changed. The proportions of each region, such as the upstream region, the mid-upstream region, the midstream region, the mid-downstream region, and the downstream region, are not limited to the illustrated case and can be appropriately changed. The division of the constant cross-section region 5 is not limited to the illustrated 3 to 5 regions; for example, it can also be the upstream region and the downstream region, or it can be 6 or more regions.

[0084] Representative particle sizes of catalyst 10 include 10a, 10b, 10c, and 10d, but the ratio and type of particle sizes are not limited to those shown. An embodiment in which one or two particle sizes of catalyst 10 are contained in one region is illustrated. Alternatively, catalysts with three or more particle sizes may be contained in one region. A constant cross-section region 5 in which multiple sizes of catalyst 10 are substantially uniformly mixed in one region is illustrated. Alternatively, the distribution of multiple sizes of catalyst 10 may be varied, for example, placing small-diameter catalyst 10 on the radially outer side of the constant cross-section region 5 and large-diameter catalyst 10 on the radially inner side of the constant cross-section region 5.

[0085] The increase in average particle size and average void area from upstream to downstream can be appropriately adjusted based on the proportion of the increase in total number of molecules caused by the decomposition of the feed gas and the location of the region where the decomposition peak occurs. The average particle size and average void area in the upstream region do not necessarily have to be the minimum. Similarly, the average particle size and average void area in the downstream region do not necessarily have to be the maximum.

Claims

1. A catalyst device for decomposing a feed gas into a reactant gas, characterized in that, The catalyst device has the following features: A flow path, comprising a constant cross-sectional region with approximately a constant cross-sectional area; and The catalyst is granular and contained within the constant cross-sectional area. By passing through the catalyst, the feed gas is decomposed into the reactant gas, and the total number of gas molecules increases. The catalyst has a first average particle size in the upstream region of the constant cross-section region, and a second average particle size larger than the first average particle size in the downstream region further downstream than the upstream region.

2. The catalyst device according to claim 1, characterized in that, The catalyst has a minimum average particle size in the upstream region of the inlet containing the constant cross-section region, a maximum average particle size in the downstream region of the outlet containing the constant cross-section region, and an intermediate average particle size in the midstream region between the upstream region and the downstream region that is larger than the minimum average particle size and smaller than the maximum average particle size.

3. The catalyst device according to claim 2, characterized in that, The average particle size of the catalyst gradually increases from upstream to downstream along the entire length of the constant cross-sectional region.

4. The catalyst device according to any one of claims 1 to 3, characterized in that, The constant cross-sectional region has a first average void area in the upstream region and a second average void area in the downstream region that is larger than the first average void area.

5. The catalyst device according to claim 4, characterized in that, The average void area of ​​the constant cross-section region along a specified length gradually increases from upstream to downstream along the entire length of the constant cross-section region.

6. The catalyst device according to any one of claims 1 to 3, characterized in that, The raw material gas is ammonia.

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