Catalyst molded body and synthesis method of ammonia using catalyst

Abstract

To provide a catalyst molded body that achieves sufficient durability in an industrial study, specifically achieves both high collapse strength and high reactivity, a producing method thereof, and a producing method of ammonia, to solve a practical problem that a Co-supported catalyst has insufficient reaction activity according to previous researches, and that durability of a catalyst is insufficient in industrialization, and to obtain an ammonia synthesis catalyst molded body satisfying the industrial level by the present producing method.SOLUTION: The catalyst molded body of the present invention comprises a composite material component (A), a titanium component (B), and a catalytically active metal M component (C). The composite material component (A) is a composite oxide of metals containing two or more Group 2 elements. The titanium component (B) is at least one selected from the group consisting of Ti, Ti3O, TiH2, Ti alloys, TiC, TiSix, TiN, and TiO. The catalytically active metal M component (C) is a transition metal.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a molded catalyst body and a method for synthesizing ammonia using the catalyst. [Background technology]

[0002] The Haber-Bosch process, a typical method for synthesizing ammonia, uses a doubly promoted iron catalyst containing Fe3O4 with a few mass percent of Al2O3 and K2O, and synthesizes ammonia by directly reacting a mixed gas of nitrogen and hydrogen with this catalyst under high temperature and pressure conditions. This technology is still used industrially today, with some improvements, using a manufacturing process that is almost the same as when it was first developed.

[0003] Meanwhile, methods for synthesizing ammonia at temperatures lower than the reaction temperature of the Haber-Bosch process have been investigated. Catalysts capable of synthesizing ammonia by contacting nitrogen and hydrogen have been investigated, and transition metals have been considered as catalytically active components. Among these, a method using ruthenium (Ru) as the catalytically active component supported on various supports as a catalyst for ammonia synthesis has been proposed as an efficient method (see, for example, Patent Document 1).

[0004] Catalysts using transition metals such as Ru have extremely high activity, making it possible to synthesize ammonia under milder conditions than those used in the Haber-Bosch process. For example, the reaction can proceed at low temperatures and pressures of 200-400°C and atmospheric pressures up to 1.1 MPa.

[0005] In addition, in view of the high cost of Ru, catalysts for ammonia synthesis in which a transition metal compound other than Ru, for example Co, is supported on a support have also been proposed. For example, Non-Patent Document 1 discloses Co / BaO-C in which cobalt is supported on barium oxide. Also, composite oxides supporting cobalt have been proposed. For example, Patent Document 2 discloses a catalyst in which cobalt is supported on a composite oxide Ba n La 1-n Ox Co / Ba supported on n La 1-n O x The composite oxide Ba n La 1-n O x is a composite oxide in a mixed state of Ba oxide and a lanthanoid oxide of a valence III. n Mg 1-n O x Co / Ba supported on n Mg 1-n O x The composite oxide Ba n Mg 1-n O x is a composite oxide in a mixed state of Ba oxide and Mg oxide. The Ba oxide and Mg oxide do not form a solid solution, and the Mg oxide particles are deposited on the surfaces of the Mg oxide particles. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-231229 [Patent Document 2] International Publication No. 2019 / 216304 [Patent Document 3] International Publication No. 2021 / 153738 [Non-patent literature]

[0007] [Non-Patent Document 1] W. Gao et. al., ACS Catal., 7 (2017) 3654―3661. Summary of the Invention [Problem to be solved by the invention]

[0008] Ammonia synthesis using the Haber-Bosch process, which mainly uses a doubly promoted iron catalyst, has been put to practical use, but because it requires high temperature and pressure conditions, there are problems with the equipment and cost involved, especially when it comes to industrialization. On the other hand, the Co-supported catalysts described in Non-Patent Document 1 and Patent Documents 2 and 3 have insufficient reaction activity and also have practical problems such as insufficient durability of the catalyst when commercialized. [Means for solving the problem]

[0009] The present inventors have discovered that the catalyst molded body of the present invention can achieve both sufficient crushing strength and high ammonia synthesis activity by using titanium and, if necessary, cobalt, and have arrived at the present invention.

[0010] That is, the gist of the present invention is as follows. [1] A catalyst molded body comprising a composite material component (A), a titanium component (B), and a catalytically active metal M component (C), the composite material component (A) is a composite oxide of metals containing two or more Group 2 elements, the titanium component (B) is at least one selected from the group consisting of Ti, TiO, TiH, a Ti alloy, TiC, TiSix, TiN, and TiO; A molded catalyst, wherein the catalytically active metal component M (C) is a transition metal. [2] The catalyst molded body according to [1], wherein the composite material component (A) is a composite oxide of metals containing barium (Ba) and magnesium (Mg). [3] The molded catalyst according to [1] or [2], wherein the catalytically active metal component M (C) is at least one selected from the group consisting of Ru, Co, Fe, and Ni. [4] The catalytically active metal M component (C) is cobalt (C1), The molded catalyst according to any one of [1] to [3], wherein the cobalt is at least one selected from the group consisting of Co, CoO, Co3O4, and CoCO3. [5] The molded catalyst according to any one of [1] to [4], wherein the content of the catalytically active metal M component (C) in the molded catalyst is 1% by mass to 50% by mass. [6] The catalyst molded article according to any one of [1] to [5], wherein the composite material component (A) is a material represented by the following general formula (1): Ba n Mg [1-n] O x (1) (where n is 0≦n<0.3, and x is 0.5≦x≦1.3) [7] The catalyst molded body according to any one of [1] to [6], wherein the particle size of the titanium component (B) in the catalyst molded body is 180 μm or less. [8] The catalyst molded body according to any one of [1] to [7], wherein the content of the titanium component (B) in the catalyst molded body is 5% by mass to 50% by mass. [9] The catalyst molded body according to any one of [1] to [8], wherein the size of the catalyst molded body is 0.3 mm to 30 mm.

[10] The bulk density of the catalyst molded body is 0.5 g cm -3 ~3g cm -3 The molded catalyst article according to any one of [1] to [9], wherein

[11] The catalyst molded article according to any one of [1] to

[10] , wherein the crushing strength of the catalyst molded article is 0.4 kgf or more.

[12] A method for producing the catalyst molded body according to any one of [1] to

[11] , The method is either the first manufacturing method or the second manufacturing method, The first production method includes a step of producing a composite material (AC) containing the catalytically active metal M component (C) by blending the catalytically active metal M component (C) while producing the composite material component (A), and then mixing the titanium component (B) into the composite material (AC) and molding the mixture; The second production method includes a step of mixing and molding the composite material component (A), the titanium component (B), and the catalytically active metal M component (C), A method for producing a molded catalyst body.

[13] A method for producing ammonia by contacting hydrogen and nitrogen with an ammonia synthesis catalyst, A method for producing ammonia, wherein the catalyst for ammonia synthesis is the molded catalyst article according to any one of [1] to

[11] . [Effects of the Invention]

[0011] The catalyst molded body of the present invention can provide a catalyst molded body that has sufficient durability for industrial application, specifically, that has both high crushing strength and high reaction activity. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a graph showing the ammonia synthesis rate in Examples 2 to 7. [Figure 2] 1 is a graph showing the ammonia synthesis rate in Examples 8 to 16. [Figure 3] 1 is a graph showing the ammonia synthesis rate in Examples 17 to 22. [Figure 4] 1 is a graph showing the ammonia synthesis rate in Examples 23 to 25. [Figure 5] 1 is a graph showing the ammonia synthesis rate in Examples 26 to 29. [Figure 6] 1 is a graph showing the ammonia synthesis rate in Examples 30 to 32. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present invention will be described in detail below. (catalyst molding) The catalyst molded body of one embodiment of the present invention (this embodiment) comprises a composite material component (A), a titanium component (B), and a catalytically active metal M component (C). The composite material component (A) is a composite oxide of metals containing two or more Group 2 elements. It is preferable that the composite material component (A) is a composite oxide of metals containing barium (Ba) and magnesium (Mg). The titanium component (B) is selected from the group consisting of Ti, Ti3O, TiH2, Ti alloys, TiC, TiSi x, TiN, and TiO. The catalytically active metal M component (C) is a transition metal. It is preferable that the catalytically active metal M component (C) is at least one selected from the group consisting of Ru, Co, Fe, and Ni. It is more preferable that the catalytically active metal M component (C) is cobalt (C1), and the cobalt component (C1) is at least one selected from the group consisting of Co, CoO, Co3O4, and CoCO3. It is also preferable that the composite material component (A) is a material represented by the following general formula (1): Ba n Mg [1-n] O x (1) (where n is 0≦n<0.3, and x is 0.5≦x≦1.3)

[0014] [Characteristics of the catalyst molding] The catalyst molded body of this embodiment (sometimes simply referred to as "catalyst molded body of the embodiment") is not particularly limited as long as it is a catalyst molded body suitable for an ammonia synthesis reaction as described below. The catalyst molded body is preferably a catalyst molded body suitable for a gas phase reaction for synthesizing ammonia from a mixed gas containing nitrogen gas and hydrogen gas. It is more preferably a catalyst molded body suitable for a reactor for producing ammonia gas on an industrial level from a mixed gas containing nitrogen gas and hydrogen gas under reaction pressure conditions equal to or higher than atmospheric pressure.

[0015] In the present invention, "suitable for gas phase reactions" means that it can be used as a solid catalyst (heterogeneous catalyst) for gas phase reactions. The phrase "suitable for a reactor for producing ammonia on an industrial level" in the present invention means that ammonia can be synthesized while an exothermic reaction occurs without a decrease in reaction pressure by passing a preheated raw material gas through a catalyst layer. The type of reactor capable of producing ammonia on an industrial level can be, for example, an adiabatic reaction type or an isothermal reaction type, and there is no problem even if the reactor has a function capable of quenching the reaction gas that has passed through the catalyst layer.

[0016] <Shape of catalyst molded body> The shape of the catalyst molded body of this embodiment is not particularly limited, and may be any shape molded using a common molding technique. Specific examples include granular, spherical, tablet, ring, macaroni, four-leaf, cube, and honeycomb shapes. Among these, from the viewpoint of catalyst production productivity, for example, cylindrical and tablet shapes are preferred.

[0017] <Size of catalyst molded body> From the viewpoint of preventing pressure loss within the reactor, the size of the catalyst molded body of this embodiment is preferably 0.3 mm to 30 mm, more preferably 0.4 mm to 20 mm, even more preferably 0.5 mm to 15 mm, and even more preferably 1 mm to 5 mm. If the size of the catalyst molded body of this embodiment is 0.3 mm or more, it is suitable for a gas phase reaction for synthesizing ammonia gas, and is particularly suitable for a reactor for producing ammonia gas on an industrial level. If the size of the catalyst molded body of this embodiment is 30 mm or less, the catalyst is easy to handle and a certain packing density can be achieved. The catalyst molded bodies of this embodiment may be of a substantially uniform size, may be a mixture of two or more sizes, or may have a certain size distribution. Here, the "size of the catalyst molded body" refers to, for example, in the case of a cylindrical extrusion molding, the diameter (D) of the circle and the length (L) of the cylinder are parameters that define the size of the extrusion molded body, and L usually refers to the size of the extrusion molded body. In the case of a spherical molded body, the size of the catalyst refers to the length of the diameter of the sphere, and can be evaluated by a dimensional measurement method. For example, if the catalyst molded body is in the shape of a tablet, it refers to its diameter.

[0018] <Bulk density of catalyst molded body> The bulk density of the catalyst molded body of this embodiment is 0.5 to 3 g cm -3 It is preferable that the density is 0.75 to 2.5 g / cm 3 More preferably, it is 1.0 to 2.0 g cm -3 The bulk density of the catalyst molded body of this embodiment is more preferably 0.5 g cm. -3If the bulk density is 3 g cm or more, a certain packing density can be achieved, which is suitable for a gas phase reaction for synthesizing ammonia gas, and is particularly suitable for a reactor for producing ammonia gas on an industrial level. -3 If the temperature is below this range, the catalyst is easy to handle and a constant gas phase reaction rate can be maintained. The "bulk density of the catalyst molding" here is the density of 1 cm 3 This refers to the weight of the catalyst molded body per unit volume, and can be evaluated using a constant volume measurement method in which the catalyst molded body is filled in a container of known volume in a stationary state, the combined weight of the container and catalyst molded body is measured, and the weight is calculated by dividing the weight by the weight of the container.

[0019] <Crushing strength of molded catalyst body> The crushing strength of the catalyst molded body of this embodiment is preferably 0.4 kgf or more, more preferably 0.8 kgf or more, and even more preferably 1.0 kgf or more. The crushing strength of the catalyst molded body of this embodiment may be 10 kgf or less. The bulk density of the catalyst molded body of this embodiment is 0.5 g cm. -3 If the above conditions are met, the reactor is suitable for a gas phase reaction for synthesizing ammonia gas, and is particularly suitable for a reactor for producing ammonia gas on an industrial level. The "crushing strength of the catalyst molded body" herein means the strength that indicates the resistance of the catalyst molded body to destruction due to compression, and can be evaluated by the compression test method described in JIS Z8841:1993 and ASTM D6175. For catalysts with the same composition, the crushing strength of a catalyst molded body depends on the molding method and molding conditions (temperature, pressure, time, etc.). However, even if the molding method and molding conditions are the same, if the material composition of the catalyst to be molded is different, the crushing strength of the molded catalyst body will differ. One way to increase the crushing strength is to add a binder, for example. However, this can affect the catalytic activity contained in the catalyst molded body, so it is important to have a catalyst molded body that achieves both crushing strength and catalytic activity. By selecting the catalyst composition described below, the catalyst molded body of this embodiment is suitable for gas-phase reactions that synthesize ammonia gas, and in particular, can achieve both crushing strength and catalytic activity that are suitable for reactors that produce ammonia gas on an industrial level.

[0020] <Specific surface area of ​​catalyst molded body> The specific surface area of ​​the catalyst molded body of this embodiment is 10 m 2 g -1 It is preferable that the length is 20 m or more, and more preferably 20 m 2 g -1 and 30m 2 g -1 The above is preferable. In the ammonia synthesis reaction, the more times nitrogen and hydrogen in the raw material gas come into contact with the surface of the catalyst molded body, the more conversion reactions to ammonia occur at the reaction active sites. Therefore, the larger the specific surface area of ​​catalyst molded bodies produced on an industrial level, the more preferable it is. The specific surface area can be measured by the N2-BET measurement method. Details of the measurement method were as described in the Examples.

[0021] [Composite material component (A)] The composite material component (A) contained in the catalyst molded article of this embodiment (sometimes referred to as "composite material component (A) according to this embodiment" or "component (A) according to this embodiment") is a composite oxide of metals containing two or more Group 2 elements. Examples of the composite oxide of metals containing two or more Group 2 elements include a composite oxide of metals containing barium (Ba) and magnesium (Mg), a composite oxide of metals containing barium (Ba) and calcium (Ca), and a composite oxide of metals containing barium (Ca) and magnesium (Mg). The composite material component (A) is preferably a composite oxide of metals containing barium (Ba) and magnesium (Mg). The composite material component (A) It is more preferable that the material be a material represented by the following general formula (1).

[0022] Ba n Mg [1-n] O x (1) (where n is 0≦n<0.3, and x is 0.5≦x≦1.3)

[0023] In the composite material component (A), n is 0≦n<0.3. n is preferably 0.005 or more, more preferably 0.01 or more, and even more preferably 0.015 or more. n is preferably 0.1 or less, more preferably 0.05 or less, and even more preferably 0.025 or less. The preferred range of n may be any combination of the preferred lower limit and the preferred upper limit. When n is 0.005 or more, the activity of the catalyst is improved. When n is significantly below the above range, the reaction-promoting effect of Ba is significantly reduced, making the molded catalyst unsuitable. Furthermore, when n is significantly above the above range, the crushing strength is reduced and the molded catalyst is not suitable.

[0024] In the composite material component (A), x is 0.5≦x≦1.3. x is preferably 0.7 or more, more preferably 0.8 or more, and even more preferably 1.0 or more. x is preferably 1.25 or less, more preferably 1.2 or less, and even more preferably 1.1 or less. The preferred range of x may be any combination of the above preferred lower limit and the above preferred upper limit.

[0025] Examples of the composite material component (A) include Ba n Mg [1-n] O x (In the above formula (1), n=0.005, x=1.0.) Ba n Mg [1-n] O x (In the above formula (1), n=0.0075, x=1.0.) Ba n Mg [1-n] O x (In the above formula (1), n=0.01, x=1.0.)

[0026] In the above general formula (1), n ​​and (1-n) are the mole ratios of Ba and Mg to the total mole of the metal elements Ba and Mg in the material represented by formula (1). Usually, this can be calculated from the blending amounts of each metal compound (oxide, inorganic acid compound, organic compound, etc.) in the raw materials. Alternatively, it can be evaluated by structural analysis, etc. In the present invention, unless specifically stated as being evaluated by structural analysis, it is calculated from the blending amounts of each metal compound (oxide, inorganic acid compound, organic compound, etc.) in the raw materials. In the general formula (1), x represents the number of moles of oxygen atoms required because when the total amount of each metal element is 1 mole, the overall charge is 0. Since the valence of each metal is not necessarily the same as the valence of each metal compound in the raw material, for example, x may be greater than 1 ([nx2+(1-n)x2] / 2=1) or less than 1.

[0027] "Manufacturing method of composite material component (A)" The composite material component (A) can be produced by known methods, such as the following methods. The composite material component (A) can be obtained by immersing magnesium hydroxide that has been calcined in air or magnesium oxide that has been calcined in advance in a solvent in which a barium compound has been dissolved or dispersed using an appropriate solvent, removing the solvent, and then calcining the resulting mixture.

[0028] <Content of composite material component (A)> The content of the composite material component (A) in the catalyst molded article of this embodiment is preferably 50.0 mass% or more, more preferably 60.0 mass% or more, and even more preferably 75.0 mass% or more. It is preferably 99.0 mass% or less, more preferably 80.0 mass% or less, and even more preferably 50.0 mass% or less. The preferred range of the content of the component (A) may be any combination of the above preferred lower limit and the above preferred upper limit.

[0029] [Titanium component (B)] The titanium component (B) contained in the catalyst molded body of this embodiment (sometimes referred to as "titanium component (B) according to this embodiment" or "component (B) according to this embodiment") is Ti, TiO, TiH, a Ti alloy, TiC, TiSi x , TiN, and TiO. At least one selected from the group consisting of Ti, TiH2, a Ti alloy, and TiO is preferred, and at least one selected from the group consisting of Ti, TiH2, and a Ti alloy is more preferred. Among these, Ti alloys are preferred from the viewpoint of catalytic performance. Furthermore, Ti is preferred, particularly from the viewpoints of cost and catalytic performance.

[0030] The above "Ti" means metallic Ti. For example, commercially available Ti powder (manufactured by Kojundo Chemical Laboratory, M 45 μm or less) can be used.

[0031] The above "TiO" means a type of titanium oxide.

[0032] "TiH2" refers to titanium hydride, such as commercially available titanium(II) hydride (>95%).

[0033] The above "Ti alloy" means metallic Ti. For example, commercially available 64 titanium alloy (Ti -6AL-4V is an example.

[0034] The above "TiC" refers to titanium carbide, for example, commercially available titanium carbide (>19.0% total carbon content). The above "TiSi x " means titanium silicide. For example, commercially available TiSi2 (M 150 μm or less) can be mentioned.

[0035] The above "TiN" means titanium nitride, for example, commercially available titanium nitride (manufactured by Kojundo Chemical Laboratory, M 53 μm or less).

[0036] The above "TiO" refers to titanium monoxide, for example, commercially available titanium monoxide (manufactured by Kojundo Chemical Laboratory, crushed powder with an M of 150 μm or less).

[0037] "Titanium component (B) particle size" The particle size of the titanium component (B) according to this embodiment is preferably 180 μm or less, and more preferably 20 to 180 μm. The particle size is preferably 30 μm or more, more preferably 40 μm or more, and even more preferably 45 μm or more. The particle size is preferably 160 μm or less, more preferably 150 μm or less, and even more preferably 75 μm or less. The preferred range of the particle size of the component (B) may be any combination of the above preferred lower limit and the above preferred upper limit. If the particle size of component (B) is 180 μm or less, it has the effect of improving catalytic activity, because the contact probability of titanium particles with catalytic active points present on the catalyst surface increases relatively.

[0038] The "particle size of component (B)" of the present invention is, for example, commercially available metallic Ti particles having a particle size in the range of 20 to 180 μm, which are separated by a dry sieving method. In the catalyst molded body of this embodiment, depending on the manufacturing method and manufacturing conditions described below, the particle size of the titanium component (B) contained in the final molded body may be different from or the same as the particle size of the above component (B).

[0039] "Titanium component (B) content" The content of the titanium component (B) in the catalyst molded article of this embodiment is preferably 5% by mass to 50% by mass. The content of the titanium component (B) is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 25% by mass or more. It is preferably 40% by mass or less, more preferably 35% by mass or less, and even more preferably 30% by mass or less. The preferred range of the content of the titanium component (B) may be any combination of the above preferred lower limit and the above preferred upper limit. If the content of titanium component (B) is 5% by mass or more, the effect of improving catalyst performance can be obtained. If the content of component (B) is 50% by mass or less, the effect of improving catalyst performance can be obtained.

[0040] The "content of titanium component (B)" in the present invention is a value calculated from the blend amount of titanium component (B) in the raw material used. The titanium component (B) is the above Ti alloy or Ti compound (TiO, TiH, Ti alloy, TiC, TiSi) other than Ti metal. x When the catalyst molded body contains at least one titanium component (B) selected from the group consisting of Ti, TiN, and TiO, the "content of titanium component (B)" in the present invention is a value calculated as the content of Ti element from the amount of titanium component (B) blended in the raw material used. In other words, the content of titanium component (B) in the catalyst molded body is the content calculated as the content of Ti element of titanium component (B) relative to 100% by mass of the catalyst molded body.

[0041] "Effects of titanium component (B)" The titanium component (B) has the effect of increasing the crushing strength of the catalyst molded article of this embodiment. As will be seen from the examples described below, when the titanium component (B) is present in an amount of, for example, 25 mass %, it is possible to achieve a practical level of crushing strength compared to a catalyst molded article that does not contain a titanium component. The reason for the increase in crushing strength due to the titanium component (B) is still under investigation, but it is presumed to be due to the interaction between the titanium component and other metal components. When the titanium component (B) is blended, a reduction in catalytic activity is observed, as occurs with blending of a conventional binder, but this reduction is minor. It is presumed that the titanium component (B) also has catalytic activity or has a catalytic promoting effect. Furthermore, a catalyst molded body containing the titanium component (B) has the effect of lowering the activation temperature of the catalyst compared to the normal activation temperature.

[0042] [Catalytically active metal M component (C)] The catalyst molded article of this embodiment contains a catalytically active metal M component (C). The catalytically active metal M component (C) is a transition metal. The catalytically active metal M component (C) is preferably at least one selected from the group consisting of Ru, Co, Fe, and Ni, and more preferably cobalt (C1).

[0043] "Transition metal" The "transition metal" of the present invention is not particularly limited, but is usually a transition metal of Group 6, 7, 8, 9 or 10 of the periodic table, preferably a transition metal of Group 6, 8 or 9, more preferably a metal of Group 8 or 9. Specific metal elements are not particularly limited, but are usually Cr, Mo, Mn, Re, Fe, Ru, Os, Co, Rh, Ni, Pd, and Pt, preferably Mo, Re, Fe, Ru, Os, and Co in that they have high bond energy with nitrogen, and more preferably Ru, Co, Fe, and Ni in that they have ammonia synthesis activity when used as an ammonia synthesis catalyst. Furthermore, Ru is preferred in that it has high catalytic activity. When economic efficiency is important, Co or Fe is preferred. The above elements may be used alone or in combination of two or more. Intermetallic compounds of these elements, such as Co3Mo3N, Fe3Mo3N, Ni2Mo3N, and Mo2N, may also be used. Preferably, each element is used alone or in combination of two or more, and more preferably, each element is used alone, which is advantageous in terms of cost.

[0044] <Cobalt component (C1)> The cobalt component (C1) according to this embodiment is preferably at least one selected from the group consisting of Co, CoO, Co3O4, and CoCO3, and the cobalt component (C) is more preferably Co.

[0045] The above "Co" means metallic Co. For example, commercially available cobalt powder (180 μm, 99.5%) can be used.

[0046] The above "CoO" is an oxide of cobalt with a valence of +2, meaning cobalt monoxide. For example, commercially available products can be mentioned.

[0047] "Co3O4" refers to the oxide of mixed valence cobalt, which contains both cobalt with a valence of +2 and cobalt with a valence of +3. For example, commercially available tricobalt tetroxide (manufactured by Kojundo Chemical Laboratory, purity 3Nup powder) can be used.

[0048] "CoCO3" refers to cobalt carbonate. For example, commercially available cobalt carbonate can be mentioned. Some cobalt carbonates contain a hydrate of cobalt(II) hydroxide and water. This is commonly known as basic cobalt carbonate. While there is no particular restriction on whether the catalyst is basic or not, basic compounds are preferred as supports suitable for ammonia synthesis reactions, and raw materials that remain basic even after catalyst preparation are preferred.

[0049] The "particle size of component (C1)" in the present invention is the average value evaluated for the raw material cobalt component (C1) used by direct observation using a transmission electron microscope. For example, when a particle size distribution is created, particle sizes in the range of 10 to 40 nm are observed, and when the average value is evaluated, the particle size is in the range of 20 to 25 nm. In the catalyst molded body of this embodiment, depending on the manufacturing method and manufacturing conditions described below, the particle size of the cobalt component (C1) contained in the final molded body may be different from or the same as the particle size of the above component (C1).

[0050] "Content of catalytically active metal M component (C)" The content of the catalytically active metal M component (C) in the molded catalyst of this embodiment is preferably 1% by mass to 50% by mass. The content of the catalytically active metal M component (C) is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more. It is preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less. The preferred range of the catalytically active metal M component (C) content may be any combination of the above-mentioned preferred lower limit and the above-mentioned preferred upper limit. When the content of the catalytically active metal M component (C) is 1% by mass or more, the catalytic performance is effectively exhibited, and when the content of component (C) is 50% by mass or less, sufficient catalytic performance can be obtained.

[0051] The "content of catalytically active metal M component (C)" in the present invention is a value calculated from the blend amount of catalytically active metal M component (C) in the raw material used.

[0052] "Effect of catalytically active metal M component (C)" The catalytically active metal M component (C) is an active component of the catalyst, and serves as a component for dissociating nitrogen molecules adsorbed on the surface of the metal M. For example, in the case of a cobalt component (C1), it serves as a component for dissociating nitrogen molecules adsorbed on the cobalt surface. Even when cobalt monoxide CoO or tricobalt tetroxide Co3O4, which belong to the oxides of the cobalt component (C), is used as a raw material, the cobalt component (C) has the ability to sufficiently dissociate nitrogen.

[0053] The specific surface area of ​​the catalyst molded body of this embodiment is not particularly limited, but is usually 0.1 m 2 g -1 More than 1m, preferably 2 g -1 More than 3m, preferably 2 g -1 That's all.

[0054] (Method of manufacturing a molded catalyst body) A method for manufacturing a catalyst molded body according to one embodiment of the present invention (sometimes referred to as "a method for manufacturing a catalyst molded body according to this embodiment" or "the manufacturing method according to this embodiment") is either the first manufacturing method or the second manufacturing method described below.

[0055] [First manufacturing method] The first production method includes the steps of producing a composite material (AC) containing the catalytically active metal M component (C) by blending the catalytically active metal M component (C) while producing the composite material component (A), and then mixing the titanium component (B) into the composite material (AC) and molding it.

[0056] [Second manufacturing method] The method includes a step of mixing and molding the composite material component (A), the titanium component (B), and the catalytically active metal M component (C).

[0057] In the first production method, the molded catalyst of this embodiment can reduce the time and cost burdens required for production by performing the steps of combining the three components, namely, the composite oxide (A), the titanium component (B), and the catalytically active metal M component (C), all at once. Combined with the fact that the molded catalyst of this embodiment has both the catalytic activity and crushing strength described above as properties of an ammonia synthesis catalyst, it can be said that this molded catalyst is a preferable molded catalyst from the viewpoint of industrial-level mass production of catalysts. In the conventional catalyst manufacturing process, a metal oxide is first molded, and then a solution in which catalytically active metal species are dissolved in an appropriate solvent is impregnated into the molded metal oxide to obtain a molded catalyst. Dividing the manufacturing process into two steps increases the cost burden and requires time to manufacture the catalyst. Using the first manufacturing method described above has the effect of shortening the manufacturing process.

[0058] Hereinafter, the first and second embodiments will be used as examples to explain the methods for producing the composite material component (A) contained in the catalyst molded article of this embodiment, respectively.

[0059] First Embodiment The method for producing a catalyst molded body according to this embodiment (the method for producing a catalyst according to the first embodiment) is an example of the first production method in which the catalytically active metal M component (C) is a cobalt component (C1). The method includes a step 1-1 of blending the cobalt component (C1) with raw materials for producing the composite material component (A) to produce a composite material (AC1) of the composite material component (A) and the cobalt component (C1), and a step 1-2 of mixing and molding the composite material component (AC1) with the titanium component (B).

[0060] In step 1-1, when the composite material component (A) is a composite oxide of metals containing barium (Ba) and magnesium (Mg), the composite material (AC1) of the composite material component (A) and the cobalt component (C1) is preferably a material represented by the following formula (3-Co):

[0061] Ba n Co m Mg [1-(n+m)] O x (3-Co) (In the above general formula (3-Co), n is 0≦n<0.3, m is 0.001≦m≦0.5 and 0.002≦n+m≦0.6, and x is 0.5≦x≦1.3)

[0062] In the composite material (AC1), m is preferably 0.005 or more, more preferably 0.0075 or more, and even more preferably 0.01 or more. m is preferably 0.4 or less, more preferably 0.3 or less, and even more preferably 0.2 or less. The preferred range of m may be any combination of the preferred lower limit and the preferred upper limit. If m is significantly below the above range, the number of reaction active sites for catalytic reaction decreases, resulting in a significant decrease in performance per weight of the catalyst molded body. Also, if m is significantly above the above range, the number of active sites per unit surface area of ​​M decreases, resulting in a decrease in performance per weight of the catalyst molded body.

[0063] In the composite material (AC1), n ​​satisfies the condition 0≦n<0.3. n is preferably 0.005 or more, more preferably 0.0075 or more, and even more preferably 0.01 or more. n is preferably 0.1 or less, more preferably 0.08 or less, and even more preferably 0.05 or less. The preferred range of n may be any combination of the preferred lower limit and the preferred upper limit. If n is significantly below the above range, the reaction-accelerating effect of Ba is significantly reduced, and if n is significantly above the above range, the strength of the molded product is significantly reduced, making it undesirable as a molded catalyst product.

[0064] In the composite material (AC1), x is 0.5≦x≦1.3. x is preferably 0.6 or more, more preferably 0.8 or more, and even more preferably 1.0 or more. x is preferably 1.2 or less, more preferably 1.15 or less, and even more preferably 1.1 or less. The preferred range of x may be any combination of the above preferred lower limit and the above preferred upper limit. The composite material (AC1) may be, for example, Ba 0.099 Co 0.01 Mg [1-(0.099+0.01)] O 1.00 (In the above formula (3-Co), m=0.01, n=0.099, x=1.00.)

[0065] "Step 1-1" In the first step, the raw materials for producing the composite material component (A) include a Ba compound and an Mg compound. Examples of Ba compounds that are raw materials derived from Ba include BaCO3, Ba(OC2H5)2, Ba(NO3)2, Ba(OH)2, and BaO. Examples of Mg compounds that are raw materials derived from Mg include MgCl2, Mg(NO3)2, MgO, Mg(OH)2, and MgCO3. Examples of Co compounds, which are raw materials derived from the cobalt component (C1), include Co nitrate (Co(NO3)2), carbonate, acetate, Co3O4, acetylacetonate, sulfate CoSO4, and hydrates thereof. Co nitrate and carbonate are preferred.

[0066] In a specific production method, for example, a Ba compound, an Mg compound, a Co compound, and optionally water are mixed to prepare a mixture. This mixture may be mixed by, for example, kneading. When water is added, the mixture may be dried. The amounts of the Ba compound, Mg compound, Co compound, and water, which may be added as needed, can be adjusted to match the composition ratio of the final synthesized catalyst molded body.

[0067] The mixture is then fired at a firing temperature preferably in the range of 400° C. to 800° C., more preferably in the range of 500° C. to 750° C., and even more preferably in the range of 500° C. to 650° C. The firing atmosphere may be air or nitrogen. For example, the temperature may be increased to 60 to 90°C at a rate of 100°C / hour, heated at that temperature for 3 to 8 hours, and then increased to 500 to 800°C at a rate of 100°C / hour, and fired for 10 to 25 hours. In the examples described later, Ba was used as the composite material (AC1). 0.015 Co 0.18 MgO x was prepared.

[0068] "Step 1-2" The composite material (AC1) obtained in step 1-1 is mixed with a titanium component, and optionally with water. Examples of the mixing method include kneading. Furthermore, when water is contained, the mixture may be dried. The drying temperature may be, for example, 50 to 90°C, 60 to 80°C, or 70°C. The titanium component includes Ti metal. The resulting mixture is molded by extrusion to obtain a molded catalyst body. For example, in the examples described below, Ba 0.015Co 0.18 MgO x and Ti metal particles as a titanium component are mixed, and extruded into pellet-shaped compacts (Ba 0.015 Co 0.18 MgO x ·Ti) was manufactured.

[0069] Second Embodiment The method for producing a catalyst molded article of this embodiment (the method for producing a catalyst of the second embodiment) is an example of the second production method. In the method for producing a catalyst molded article of the second embodiment, the component of the composite material component (A) is "Ba n Mg [1-n] O x In the second manufacturing method, the composite material component (A) is "Ba n Mg [1-n] O x " and the "Ba obtained in the 2-1 step. n Mg [1-n] O x " is mixed with a metal M compound derived from a transition metal M, a Ti metal or Ti compound derived from a titanium component (B), and, if necessary, water or water and an organic compound, etc., to form "M m / Ba n Mg [1-n] O x and step 2-2 of manufacturing "Ti".

[0070] "Step 2-1" In the step 2-1, the component of the composite material component (A) “Ba n Mg [1-n] O x The manufacturing method of "Composite material component (A)" is the same as the method described above in "Manufacturing method of composite material component (A)".

[0071] "2nd-2nd process" The "Ba" obtained in step 2-1 n Mg [1-n] O x When blending the "Ba" compound derived from the transition metal M, and the Ti metal or Ti compound derived from the titanium component (B), the order of addition is not particularly limited. For example, (1) "Ba" compound n Mg[1-n] O x ", (2) a metal M compound derived from a transition metal M, and (3) a Ti metal or Ti compound derived from a titanium component (B). n Mg [1-n] O x The order may be (1) Ti metal or Ti compound derived from the titanium component (B), and (2) a metal M compound derived from the transition metal M. The resulting mixture is molded by extrusion molding to obtain a molded catalyst body. The type of transition metal M and the metal M compound that is the raw material derived from the transition metal M are the same as the "transition metal" described above in [Catalytically active metal M component (C)]. For example, Ru compounds that are raw materials derived from Ru include RuCl3, Ru(NO)(NO3)3, Ru(NO3)3, and Ru3(CO). 12 , etc.

[0072] "Transition metals and transition metal compounds" The "transition metal" of the present invention is the same as that described above.

[0073] The transition metal compound is not particularly limited, and examples thereof include inorganic compounds or organic transition metal complexes of transition metals that are easily thermally decomposed, such as transition metal complexes, transition metal oxides, and transition metal salts such as nitrates and hydrochlorides. For example, Ru compounds include triruthenium dodecacarbonyl [Ru3(CO) 12 ], dichlorotetrakis(triphenylphosphine)ruthenium(II) [RuCl2(PPh3)4], dichlorotris(triphenylphosphine)ruthenium(II) [RuCl2(PPh3)3], tris(acetylacetonato)ruthenium(III) [Ru(acac)3], ruthenocene [Ru(C5H5)], nitrosyl ruthenium nitrate [Ru(NO)(NO3)3], potassium ruthenate, ruthenium oxide, ruthenium nitrate, ruthenium chloride, etc. Tris(acetylacetonato)ruthenium(III) [Ru(acac)3] is preferred.

[0074] Iron compounds include iron pentacarbonyl [Fe(CO)5] and triiron dodecacarbonyl [Fe3(CO) 12 ], iron nonacarbonyl [Fe2(CO)9], iron tetracarbonyl iodide [Fe(CO)4I2], tris(acetylacetonato)iron(III) [Fe(acac)3], ferrocene [Fe(C5H5)2], iron oxide, iron nitrate, and iron chloride (FeCl3).

[0075] Co compounds include: Examples include cobalt octacarbonyl [Co2(CO)8], tris(acetylacetonato)cobalt(III), cobaltocene [Co(C5H5)2], cobalt oxide, cobalt nitrate, cobalt carbonate, and cobalt chloride. Among these transition metal compounds, [Ru3(CO) 12 ], [Fe(CO)5], [Fe3(CO) 12 Carbonyl complexes of transition metals such as [Fe(CO)(II)], [Fe(CO)(III)], and [Co(CO)(III)] are preferred in that the transition metals are supported by heating after loading, and therefore the reduction treatment described below can be omitted when producing a molded catalyst.

[0076] The amount of the transition metal compound used is not particularly limited, and an appropriate amount can be used to achieve the desired loading amount. However, the amount is usually 2% by mass or more, preferably 10% by mass or more, more preferably 20% by mass or more, and usually 50% by mass or less, preferably 40% by mass or less, more preferably 30% by mass or less, based on the mass of the support (composite material component (A) + titanium component (B)) used.

[0077] Specific examples of methods that can be used to support the transition metal compound on a carrier include physical mixing, chemical impregnation, CVD (chemical vapor deposition), and sputtering.

[0078] The physical mixing method is a method in which the support (composite material component (A) + titanium component (B)) and the transition metal compound are mixed in a solid state, and then heated in a stream of an inert gas such as nitrogen, argon, or helium, or under vacuum. The heating temperature is not particularly limited, but is usually 200°C or higher and 600°C or lower. The heating time is not particularly limited, but is usually preferably 2 hours or longer.

[0079] Chemical impregnation is a treatment method in which a liquid is permeated into the gaps between particles of a solid material (such as metal, wood, ceramics, etc.). This method is applied by immersing a ceramic support, such as a metal oxide with an appropriate specific surface area and acidic or basic properties, in a metal salt solution, and then drying it to evaporate the solvent, thereby dispersing and immobilizing the catalytically active component on the support surface.

[0080] The method for reducing the transition metal compound (hereinafter referred to as reduction treatment) is not particularly limited as long as it does not impair the object of the present invention, but examples include a method in which the reduction treatment is carried out in an atmosphere containing a reducing gas, or a method in which a reducing agent such as NaBH4, NH2NH2, or formalin is added to a solution containing the transition metal compound to precipitate it on the surface of the metal hydride, but the reduction treatment is preferably carried out in an atmosphere containing a reducing gas, such as hydrogen, ammonia, methanol (vapor), ethanol (vapor), methane, or ethane. During the reduction treatment, components other than the reducing gas may coexist in the reaction system as long as they do not inhibit the object of the present invention, particularly the ammonia synthesis reaction. Specifically, during the reduction treatment, in addition to a reducing gas such as hydrogen, a gas such as argon or nitrogen that does not inhibit the reaction may coexist, and it is preferable to coexist with nitrogen. When the reduction treatment is carried out in a gas containing hydrogen, the reduction treatment can be carried out in parallel with the production of ammonia, which will be described later, by making nitrogen coexist with hydrogen. That is, when the catalyst for ammonia synthesis of the present invention is used as a catalyst for ammonia synthesis, which will be described later, the transition metal compound may be reduced and converted into a transition metal by supporting the transition metal compound on the metal hydride and placing the resultant under reaction conditions for the ammonia synthesis reaction.

[0081] The temperature during the reduction treatment is not particularly limited, but is usually 200° C. or higher, preferably 300° C. or higher, and is usually a temperature below the decomposition temperature of the transition metal compound, preferably below 600° C. This is because, by performing the reduction treatment within the above temperature range, the growth of the transition metal occurs sufficiently and within a preferred range. The pressure during the reduction treatment is not particularly limited, but is usually 0.01 MPa or more, preferably 5 MPa or more, and more preferably 10 MPa or more. If the pressure during the reduction treatment is the same as the ammonia synthesis conditions described below, complicated operations become unnecessary, which is advantageous in terms of production efficiency. The time for the reduction treatment is not particularly limited, but when carried out at normal pressure, it is usually 1 hour or more, preferably 2 hours or more. When the reaction is carried out under high pressure conditions, for example, at 1 MPa or higher, the reaction time is preferably 1 hour or longer.

[0082] (Ammonia synthesis catalyst) The catalyst for ammonia synthesis of this embodiment can use the above-described catalyst molded body of this embodiment. The method for producing the ammonia synthesis catalyst of this embodiment is the same as the method for producing the molded catalyst of this embodiment described above.

[0083] <Method of synthesizing ammonia> The method for synthesizing ammonia of the present invention (hereinafter sometimes referred to as the synthesis method of the present invention) is a method for synthesizing ammonia by using the catalyst for ammonia synthesis of the present invention as a catalyst and reacting hydrogen and nitrogen on the catalyst. The specific synthesis method is not particularly limited as long as it is a method in which hydrogen and nitrogen are brought into contact on the catalyst to synthesize ammonia, and ammonia can be produced in accordance with any known synthesis method.

[0084] In the method for synthesizing ammonia of the present invention, the catalyst is usually heated when hydrogen and nitrogen are brought into contact on the catalyst to synthesize ammonia. The reaction temperature in the synthesis method of the present invention is not particularly limited, but is usually 50° C. or higher, preferably 200° C. or higher, more preferably 300° C. or higher, and usually 600° C. or lower, preferably 500° C. or lower, more preferably 450° C. or lower. Since ammonia synthesis is an exothermic reaction, a lower temperature range is advantageous for ammonia synthesis in terms of chemical equilibrium, but in order to obtain a sufficient ammonia synthesis rate, it is preferable to carry out the reaction within the above temperature range. In the synthesis method of the present invention, the molar ratio of nitrogen to hydrogen brought into contact with the catalyst is not particularly limited, but is usually carried out at a ratio of hydrogen to nitrogen (H / N (volume / volume)) of usually 0.4 or more, preferably 0.5 or more, more preferably 1 or more, and usually 10 or less, preferably 3 or less.

[0085] The reaction pressure in the synthesis method of the present invention is not particularly limited, but is usually 0.01 MPa or more, preferably 0.1 MPa or more, and usually 20 MPa or less, preferably 15 MPa or less, more preferably 10 MPa or less, in terms of the pressure of the mixed gas containing nitrogen and hydrogen. In consideration of practical use, it is preferable to carry out the reaction under pressurized conditions of atmospheric pressure or higher.

[0086] In the synthesis method of the present invention, before nitrogen and hydrogen are brought into contact with the catalyst, it is preferable to remove moisture and oxides adhering to the catalyst by a method using a dehydrating agent, a cryogenic separation method, hydrogen gas, etc. Examples of the removal method include reduction treatment. In the synthesis method of the present invention, in order to obtain a better ammonia yield, it is preferable that the water content in the nitrogen and hydrogen used in the synthesis method of the present invention is low, and although there are no particular limitations, the total water content in the mixed gas of nitrogen and hydrogen is usually 100 ppm or less, preferably 50 ppm or less, and more preferably 1 ppm or less.

[0087] In the synthesis method of the present invention, the type of reaction vessel is not particularly limited, and a reaction vessel that can be normally used for ammonia synthesis reactions can be used. Specific reaction types that can be used include, for example, a batch reaction type, a closed circulation reaction type, and a flow reaction type. Among these, a flow reaction type is preferred from a practical standpoint. Furthermore, any of the following methods can be used: a single type of reactor filled with a catalyst, a method in which multiple reactors are connected, or a reactor having multiple reaction layers within the same reactor. Since the reaction of synthesizing ammonia from hydrogen and nitrogen is an exothermic reaction accompanied by volume contraction, it is industrially preferable to remove the heat of reaction in order to increase the ammonia yield, and a known reaction apparatus equipped with a commonly used heat removal means may be used. For example, specifically, a method of connecting a plurality of reactors filled with a catalyst in series and installing an intercooler at the outlet of each reactor to remove heat may be used.

[0088] In the method for synthesizing ammonia of the present invention, the catalyst for synthesizing ammonia obtained by the synthesis method of the present invention can be used alone or in combination with other known catalysts that can be normally used for ammonia synthesis.

[0089] The catalyst for ammonia synthesis of the present invention will be described in detail below using first and second embodiments of the present invention, but the technical scope of the present invention is not limited thereto. [Example]

[0090] The present invention will be described in more detail below with reference to the following examples. The ammonia synthesis activity was evaluated by measuring the amount of NH3 produced by gas chromatography or by dissolving the produced NH3 in an aqueous sulfuric acid solution and quantifying the solution by ion chromatography to determine the ammonia synthesis rate.

[0091] (Method for evaluating crushing strength) Measuring device: Kiya-type hardness tester (manufactured by Fujiwara Seisakusho Co., Ltd., model number: 043019-B) Measurement method: A cylindrical sample with a diameter of approximately 2 mm and a length of 4 mm was placed on a special sample stage, and the pressure attachment was gradually lowered until the side of the sample came into contact with the pressure attachment, and pressure was gradually applied until the sample was crushed. The maximum pressure applied to the pressure attachment until the sample was crushed was taken as the crushing strength. Evaluation criteria The crushing strength of each catalyst molded body was evaluated according to the following criteria.

[0092] A: The crushing strength is over 1.0 kgf, which is excellent strength for industrial production solid catalysts. B: The crushing strength is 0.4 kgf or more, and it can be used as a solid catalyst for industrial production. C: The crushing strength is less than 0.4 kgf, making it difficult to use as a solid catalyst for industrial production.

[0093] (BET specific surface area measurement method) The BET specific surface area was measured by adsorbing nitrogen gas onto the surface of the object at liquid nitrogen temperature, and then determining the area from the adsorption isotherm based on the adsorption and desorption of nitrogen gas at -196°C. The analytical conditions were as follows:

[0094] [Measurement conditions] Measurement equipment: High-speed specific surface / pore distribution measurement equipment BELSORP-mini 2 (MicrotracBEL) Adsorbed gas: Nitrogen 99.99995% by volume. Adsorption temperature: liquid nitrogen temperature -196°C.

[0095] (Ion chromatogram analysis) The ammonia gas discharged from the reaction vessel was dissolved in a 5 mM sulfuric acid solution, and the captured ammonium ions (NH + ) was analyzed by ion chromatography under the following analytical conditions:

[0096] [Measurement conditions] Equipment: Shimadzu Corporation HPLC Prominence Detector: Electrical conductivity detector CDD10A VP (Shimadzu Corporation) Column: Shim-pack IC-C4LC-2000 plus ion chromatography column (Shimadzu Corporation) Eluent: oxalic acid (2.5 mM) aqueous solution Flow rate: 1.0mL min -1 Column temperature: 40℃

[0097] Example 1 (Preparation of Catalyst Molded Body) [Ba 0.015 Co 0.18 MgO x Preparation of Co(NO3) 2· 20.1 g of 6H2O powder (purity 98% by mass or more), 1.50g of Ba(NO3)2 powder (purity 99.8%, particle size 100μm or more) Water and 22.5 g of Mg(OH)2 (MgO content 67.4% by mass), The mixture was mixed under atmospheric pressure to prepare a mixture. -1 The temperature was increased to 80°C at a rate of 1°C / min, and the mixture was heated at that temperature for 5 hours. After that, the temperature was increased to 600°C at a rate of 2°C / min, and the mixture was fired for 18 hours. This resulted in the formation of a composite metal oxide called Ba 0.015 Co 0.18 MgO x The BET surface area was 26 m 2 g -1 It was. The "physical mixing" in this embodiment refers to mixing using an agate mortar or the like.

[0098] [Ba 0.015 Co 0.18 MgO x Preparation of (25 wt.%) Ti compacts] The above obtained Ba 0.015 Co 0.18 MgO x 7.5g and 2.5 g of metal Ti powder (purity 99 mass%, average particle size 45 μm), The mixture was dried at 70°C and then extruded to prepare a pellet-shaped molded product. 0.015 Co 0.18 MgO x (25 wt.%) Ti) was obtained (Co content in the oxide: 20 wt.%). As a result of evaluation using the above evaluation method, the BET surface was 19m 2 g -1 The evaluation result for crushing strength was A. Ammonia synthesis was carried out below using the catalyst molded body obtained in this example as a catalyst for ammonia synthesis.

[0099] (Ammonia synthesis reaction) The catalyst molded body was pretreated in a nitrogen and hydrogen gas atmosphere at 600° C. for 20 hours. A reaction (hereinafter referred to as ammonia synthesis reaction) was carried out in which nitrogen gas (N2) and hydrogen gas (H2) were reacted on a catalyst to produce ammonia (NH3). 0.14 g of the pretreated ammonia synthesis catalyst was packed into a glass tube, and the ammonia synthesis reaction was carried out in a fixed-bed flow reactor. The moisture concentration of the raw material gases was 1 ppm or less. The raw material gas flow rate was N2:15 mL min -1 , H2: 45 mL min -1 , total 60mL min -1 The reaction was carried out at a pressure of 0.8 MPaG and a reaction temperature of 400°C or 350°C. The rate of ammonia production was expressed as the amount of ammonia produced per unit time (mmol h -1 ) is calculated by dividing by the amount of catalyst used.

[0100] (Ammonia production rate) The gas coming out of the fixed-bed flow reactor was bubbled into a 5 mM aqueous sulfuric acid solution to dissolve the ammonia in the gas, and the generated ammonium ions were quantified by ion chromatography using the method described above. The ammonia production rate at 400°C was 15.8 mmol g -1 h -1 It was.

[0101] Examples 2 to 7 "Dependence of Co content in oxide" (Preparation of Catalyst Molded Body) The Co contents of Examples 2 to 7 were the same as those of Example 1, except that the Co contents shown in Table 1 were used. Pellet-shaped molded bodies were prepared in the same manner as in Example 1. As a result, the catalyst molded bodies of this embodiment were obtained using the (Ba) 0.015 Co m MgO x The crushing strength evaluation results are shown in Table 1.

[0102] (Ammonia synthesis reaction) Example 1 (Ba 0.015 Co 0.18 MgO x (Ba·(25 wt.%)Ti) obtained in Examples 2 to 7 was used instead. 0.015 Co y MgO x A reaction to produce ammonia (NH3) (hereinafter referred to as ammonia synthesis reaction) was carried out in the same manner as in Example 1, except that a 25 wt.% Ti (Co content in the oxide: 5 wt.% to 50 wt.%) Ti was used and the reaction temperature was 350°C.

[0103] (Ammonia production rate) The rate of ammonia production was measured in the same manner as in Example 1. The results are shown in Table 1 and FIG.

[0104] [Table 1]

[0105] (Examples 8 to 17, Comparative Examples 1 and 2) "Dependence of raw materials derived from titanium components" (Preparation of Catalyst Molded Body) In Examples 8 to 17, pellet-shaped molded bodies were prepared in the same manner as in Example 4, except that the titanium metal species and Ti compounds shown in Table 2 were used instead of the Ti metal in Example 4. As a result, the catalyst molded bodies of this embodiment were obtained using the (Ba 0.015 Co 0.18 MgO x The crushing strength evaluation results are shown in Table 2. The Ti component contents in Examples 8 to 17 were values ​​calculated from the titanium metal species and Ti compound blending amounts shown in Table 2 and converted into Ti element contents.

[0106] (Ammonia synthesis reaction) (Ba) obtained from Ti metal in Example 1 0.015 Co 0.18 MgO x (Ba·(25wt.%)Ti) obtained from the titanium components shown in Table 2 0.015 Co 0.18 MgO x A reaction to produce ammonia (NH3) (hereinafter referred to as ammonia synthesis reaction) was carried out in the same manner and under the same conditions as in Example 2, except that a 25 wt.% Ti (Ti) was used.

[0107] (Ammonia production rate) The rate of ammonia production was measured in the same manner as in Example 1. The results are shown in Table 2 and FIG.

[0108] [Table 2]

[0109] Examples 17 to 22 "Dependence of titanium content" (Preparation of Catalyst Molded Body) In Examples 18 to 22, the Ti content was changed from 25 wt.% in Example 4 to the Ti content shown in Table 2. The pellet-shaped molded bodies were prepared in the same manner as in Example 4. As a result, the catalyst molded bodies of this embodiment were obtained with the Ti content shown in Table 1. 0.015 Co 0.18MgO x The results of the crushing strength evaluation are shown in Table 3.

[0110] (Ammonia synthesis reaction) The Ti content of Example 1 was obtained (Ba 0.015 Co 0.18 MgO x (Ba) obtained from the Ti content shown in Table 3 instead of (25 wt.%)Ti). 0.015 Co 0.18 MgO x A reaction to produce ammonia (NH3) (hereinafter referred to as ammonia synthesis reaction) was carried out in the same manner and under the same conditions as in Example 2, except that Ti (x wt.%) was used.

[0111] (Ammonia production rate) The rate of ammonia production was measured in the same manner as in Example 1. The results are shown in Table 3 and FIG.

[0112] [Table 3]

[0113] Examples 23 to 25 "Ti particle size dependence" (Preparation of Catalyst Molded Body) The average Ti particle diameters of Examples 23 to 26 were changed from 45 μm in Example 4 to the Ti average particle diameters shown in Table 4. Pellet-shaped molded bodies were prepared in the same manner as in Example 4. As a result, the catalyst molded bodies of this embodiment were obtained with the average Ti particle diameters shown in Table 4. 0.015 Co 0.18 MgO x The crushing strength evaluation results are shown in Table 4.

[0114] (Ammonia synthesis reaction) The average particle size of Ti in Example 4 was obtained (Ba 0.015 Co 0.18 MgO x (Ba) obtained from the average particle size of Ti shown in Table 3 instead of (25 wt%)Ti). 0.015 Co0.18 MgO x A reaction to produce ammonia (NH3) (hereinafter referred to as ammonia synthesis reaction) was carried out in the same manner and under the same conditions as in Example 4, except that a 25 wt.% Ti catalyst was used.

[0115] (Ammonia production rate) The rate of ammonia production was measured in the same manner as in Example 1. The results are shown in Table 4 and FIG.

[0116] [Table 4]

[0117] Examples 26 to 29 "Dependence of BaCoMgO preparation temperature" (Preparation of Catalyst Molded Body) Ba in Examples 26 to 29 0.015 Co 0.18 MgO x The preparation temperature was changed from 600°C in Example 4 to the preparation temperatures shown in Table 5. The pellet-shaped molded bodies were prepared in the same manner as in Example 4. As a result, the catalyst molded bodies of this embodiment were obtained as shown in Table 5 (Ba 0.015 Co 0.18 MgO x The crushing strength evaluation results are shown in Table 5.

[0118] (Ammonia synthesis reaction) The results obtained at the preparation temperature of Example 4 (Ba 0.015 Co 0.18 MgO x (Ba·(25 wt.%)Ti) obtained from the preparation temperatures shown in Table 3. 0.015 Co 0.18 MgO x A reaction to produce ammonia (NH3) (hereinafter referred to as ammonia synthesis reaction) was carried out in the same manner and under the same conditions as in Example 4, except that a 25 wt.% Ti catalyst was used.

[0119] (Ammonia production rate) The rate of ammonia production was measured in the same manner as in Example 1. The results are shown in Table 5 and FIG.

[0120] [Table 5]

[0121] Examples 30 to 32 "Dependence on the type of Co compound" (Preparation of Catalyst Molded Body) The types of Co compounds used in Examples 30 to 32 were the Co nitrates of Example 4, but the Co compounds shown in Table 6 were used instead. Pellet-shaped molded bodies were prepared in the same manner as in Example 4. As a result, the catalyst molded bodies of this embodiment were obtained using the Co compounds shown in Table 6. 0.015 Co 0.18 MgO x The crushing strength evaluation results are shown in Table 6.

[0122] (Ammonia synthesis reaction) The results obtained in Example 4 when Co nitrate was used (Ba 0.015 Co 0.18 MgO x Instead of Ti (25 wt.%), the Co compounds shown in Table 6 were used (Ba 0.015 Co 0.18 MgO x A reaction to produce ammonia (NH3) (hereinafter referred to as ammonia synthesis reaction) was carried out in the same manner and under the same conditions as in Example 4, except that ammonia (25 wt%) Ti was used.

[0123] (Ammonia production rate) The rate of ammonia production was measured in the same manner as in Example 1. The results are shown in Table 6 and FIG.

[0124] [Table 6]

[0125] Example 33 (Preparation of Catalyst Molded Body) [Ba 0.015 MgO x Preparation of 0.67g of Ba(NO3)2 powder (purity 99.8%, particle size 100μm or more) 12.42g of water, 14.61 g of Mg(OH)2 (MgO content 67.4% by mass), The mixture was dried at 70°C and then heated at 5°C for 1 min. -1 The temperature was raised to 700°C at a rate of 100°C and fired for 24 hours. This resulted in the formation of a composite metal oxide called Ba 0.015 MgO x The BET surface area was 26 m 2 g -1 It was. The "physical mixing" in this embodiment refers to mixing using an agate mortar or the like.

[0126] [Ru / Ba 0.015 MgO x Preparation of (25 wt.%) Ti compacts] The above obtained Ba 0.015 MgO x 7.20g and 1.59 g of Ru(NO)(NO3)3 aqueous solution (Ru concentration 18.81 mass%), 2.50 g of metal Ti powder (purity 99 mass%, average particle size 45 μm), Water and The resulting mixture was dried and then heated to 300°C in a nitrogen atmosphere. The resulting powder catalyst was extruded to prepare a pellet-shaped molded body. This gave the catalyst molded body of this embodiment, (Ru / Ba 0.015 MgO x (25 wt.%) Ti) was obtained (Ru loading 3 wt.%). As a result of evaluation using the above evaluation method, the BET surface was 10 to 20 m 2 / g. The evaluation result of the crushing strength was A. Ammonia synthesis was carried out below using the catalyst molded body obtained in this example as a catalyst for ammonia synthesis.

[0127] (Ammonia synthesis reaction) The catalyst for ammonia synthesis was pretreated in a nitrogen and hydrogen gas atmosphere at 600° C. for 20 hours. A reaction (hereinafter referred to as ammonia synthesis reaction) was carried out in which nitrogen gas (N2) and hydrogen gas (H2) were reacted on a catalyst to produce ammonia (NH3). 0.14 g of the pretreated ammonia synthesis catalyst was packed into a glass tube, and the ammonia synthesis reaction was carried out in a fixed-bed flow reactor. The moisture concentration of the raw material gases was 1 ppm or less. The raw material gas flow rate was N2:15 mL min -1 , H2: 45 mL min -1 , total 60mL min -1 The pressure was set to 0.8 MPaG and the reaction temperature was 350°C.

[0128] (Ammonia production rate) The gas coming out of the fixed-bed flow reactor was bubbled through a 0.005 M aqueous sulfuric acid solution to dissolve the ammonia in the gas, and the generated ammonium ions were quantified by ion chromatography using the method described above. The rate of ammonia production at 400°C was 21.6 mmol g -1 h -1 , was.

[0129] (Consideration) The molded catalyst showed excellent ammonia synthesis activity by using appropriate transition metal components as raw materials, and the molded catalyst fully satisfied the crushing strength, one of the requirements for use as an industrial catalyst. The role of titanium components, such as titanium compounds and titanium alloys, is thought to be to promote the reduction of the transition metal elements contained in the molded catalyst during ammonia synthesis, and to increase the crushing strength of the molded catalyst through interaction with metal oxides of Group 2 elements, such as magnesium oxide.

Claims

1. A catalyst molded body comprising a composite material component (A), a titanium component (B), and a catalytically active metal M component (C), the composite material component (A) is a composite oxide of metals containing two or more Group 2 elements, The titanium component (B) is Ti, Ti ３ O, TiH ２ , Ti alloy, TiC, TiSi ｘ , TiN, and TiO, A catalyst molded body, wherein the catalytically active metal component (C) is a transition metal.

2. 2. The catalyst molded body according to claim 1, wherein the composite material component (A) is a composite oxide of metals containing barium (Ba) and magnesium (Mg).

3. 2. The catalyst molded article according to claim 1, wherein the catalytically active metal component (C) is at least one selected from the group consisting of Ru, Co, Fe, and Ni.

4. the catalytically active metal M component (C) is cobalt (C1); The cobalt may be Co, CoO, Co ３ O ４ and CoCO ３ The catalyst molded article according to claim 1, which is at least one selected from the group consisting of:

5. 2. The molded catalyst according to claim 1, wherein the content of the catalytically active metal M component (C) in the molded catalyst is 1% by mass to 50% by mass.

6. The catalyst molded article according to any one of claims 1 to 5, wherein the composite material component (A) is a material represented by the following general formula (1): Ba ｎ Mẽ ［１－ｎ］ O ｘ (1) (where n is 0≦n<0.3, and x is 0.5≦x≦1.3)

7. 6. The catalyst molded body according to claim 1, wherein the particle size of the titanium component (B) in the catalyst molded body is 180 μm or less.

8. 6. The catalyst molded body according to claim 1, wherein the content of the titanium component (B) in the catalyst molded body is 5% by mass to 50% by mass.

9. The catalyst molded body according to any one of claims 1 to 5, wherein the catalyst molded body has a size of 0.3 mm to 30 mm.

10. The bulk density of the catalyst molded body is 0.5 g cm －３ ~3g cm －３ The catalyst molded body according to any one of claims 1 to 5,

11. The catalyst molded article according to any one of claims 1 to 5, wherein the crushing strength of the catalyst molded article is 0.4 kgf or more.

12. A method for producing the catalyst molded body according to any one of claims 1 to 5, comprising: The method is either the first manufacturing method or the second manufacturing method, The first production method includes a step of producing a composite material (AC) containing the catalytically active metal M component (C) by blending the catalytically active metal M component (C) while producing the composite material component (A), and then mixing the titanium component (B) into the composite material (AC) and molding the mixture; The second production method includes a step of mixing and molding the composite material component (A), the titanium component (B), and the catalytically active metal M component (C). A method for producing a molded catalyst body.

13. A method for producing ammonia by contacting hydrogen and nitrogen with an ammonia synthesis catalyst, comprising: A method for producing ammonia, wherein the catalyst for ammonia synthesis is the catalyst molded article according to any one of claims 1 to 5.

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