Catalyst for decomposition of ammonia, and method for decomposition of ammonia

Abstract

The present invention relates to a catalyst for decomposition of ammonia and a method for decomposition of ammonia. The catalyst comprises a carrier and a catalytically active component supported by the carrier, the catalytically active component comprising; i) ruthenium as a first metal; ii) a second metal; and iii) a third metal, wherein the second metal and the third metal are each independently at least one selected from the group consisting of lanthanum (La), cerium (Ce), aluminum (Al), and zirconium (Zr).

Description

Ammonia decomposition catalyst and ammonia decomposition method

[0001] Cross-citation with related application(s)

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0098840, filed July 28, 2023, and Korean Patent Application No. 10-2024-0097992, filed July 24, 2024, the entire contents of which are incorporated herein by reference.

[0003]

[0004] The present invention relates to an ammonia decomposition catalyst and an ammonia decomposition method.

[0005] As interest in the environment and energy has grown recently, the issue of the hydrogen economy is also coming to the fore.

[0006] The hydrogen economy refers to an economic and industrial structure that uses hydrogen as its primary energy source. In other words, it is an economic system that moves beyond the current fossil fuel-centric energy system, expanding the use of hydrogen-powered machines like power generation systems, heat generation systems, and automobiles, and creating new industries and markets in all fields necessary for the stable production, storage, and transportation of hydrogen.

[0007] In these systems, hydrogen can be produced through a variety of means, such as water electrolysis, natural gas reforming, and biomass gasification, and distributed through pipeline networks or transported to hydrogen fuel cells. Because direct hydrogen transport is expensive and risky, there is growing interest in technologies that can transport hydrogen easily, safely, and at a low cost.

[0008] One way to efficiently store and transport hydrogen is to transport ammonia and decompose the transported ammonia to use it as a hydrogen source.

[0009] The reaction that decomposes ammonia into hydrogen and nitrogen is an endothermic reaction with a large energy difference, and the activation energy of the reaction is also very large, so a lot of energy is required to obtain a useful amount of hydrogen gas as a product, and accordingly, a lot of cost is consumed in producing hydrogen.

[0010] Accordingly, interest in research on ammonia decomposition catalysts with high ammonia decomposition efficiency is increasing.

[0011] The present specification aims to provide an ammonia decomposition catalyst having excellent low-temperature decomposition performance at high space velocity.

[0012] In addition, the present specification aims to provide an ammonia decomposition catalyst that can prevent catalytic thermal agglomeration, thereby providing reaction process stability and having an improved lifespan.

[0013] In addition, the present specification seeks to provide an ammonia decomposition method using such an ammonia decomposition catalyst.

[0014] The present specification provides an ammonia decomposition catalyst comprising a carrier and a catalytically active component supported on the carrier, wherein the catalytically active component comprises: i) a first metal, ruthenium (Ru); and ii) a second metal; and iii) a third metal; wherein the second metal and the third metal are each independently at least one selected from the group consisting of lanthanum (La), cerium (Ce), aluminum (Al), and zirconium (Zr), and the content of the first metal, ruthenium, is 0.1 to 1 part by weight based on 100 parts by weight of the total catalyst, has a porosity of 30 to 60%, and has a median pore size value of 50 to 200 μm.

[0015] Specifically, the second metal and the third metal may be different from each other.

[0016]

[0017] According to one example, the content of the first metal, ruthenium, may be about 0.1 to about 1 part by weight, or about 0.1 part by weight or more, or about 0.2 part by weight or more, or about 0.3 part by weight or more, or about 0.4 part by weight or more, based on 100 parts by weight of the entire catalyst, and at the same time may be about 1 part by weight or less, or about 0.9 part by weight or less, or about 0.8 part by weight or less, or about 0.7 part by weight or less, or about 0.6 part by weight or less, or about 0.5 part by weight or less.

[0018]

[0019] In one example, the ammonia decomposition catalyst may have a porosity of about 30 to about 60%, or greater than about 10%, or greater than about 20%, or greater than about 30%, or greater than about 40%, or greater than about 50%, and at the same time, less than or equal to about 60%, or less than or equal to about 58%, or less than or equal to about 56%, or less than or equal to about 54%, or less than or equal to about 52%.

[0020]

[0021] According to one example, the median pore size of the ammonia decomposition catalyst may be about 50 to 200 μm, or about 50 μm or more, or about 75 μm or more, or about 100 μm or more, or about 120 μm or more, or about 140 μm or more, or about 150 μm or more, and at the same time about 200 μm or less, or about 180 μm or less, or about 160 μm or less.

[0022] In one example, the ammonia decomposition catalyst may have a pore volume of about 0.1 to 0.4 mL / g, or greater than or equal to about 0.1 mL / g, or greater than or equal to about 0.2 mL / g, or greater than or equal to about 0.25 mL / g, or greater than or equal to about 0.3 mL / g, or greater than or equal to about 0.33 mL / g, and at the same time less than or equal to about 0.4 mL / g, or less than or equal to about 0.35 mL / g.

[0023]

[0024] In one example, the carrier may be a porous spherical structure.

[0025]

[0026] In one example, the carrier may be an inorganic oxide structure. More specifically, the carrier may be an inorganic oxide comprising at least one element selected from the group consisting of aluminum (Al), zirconium (Zr), cerium (Ce), and silicon (Si). More specifically, the carrier may be aluminum silicate (Al2SiO5).

[0027]

[0028] According to one example, the content of the catalytically active component may be about 20 parts by weight or less, or about 0.1 parts by weight or more, or about 0.5 parts by weight or more, or about 1 part by weight or more, based on 100 parts by weight of the entire catalyst, and at the same time, may be about 20 parts by weight or less, about 18 parts by weight or less, or about 15 parts by weight or less, or about 11 parts by weight or less.

[0029]

[0030] In one example, the weight ratio of (second metal):(third metal) may be from about 1:99 to about 30:70, or greater than about 1:99, or greater than about 10:90, or greater than about 20:80, or greater than about 23:77, and at the same time less than or equal to about 30:70, or less than or equal to about 25:75.

[0031]

[0032] In one example, the weight ratio of (first metal):(second metal and third metal oxide) may be from 1:99 to 10:90, or from about 3:97 to 7:93.

[0033]

[0034] In one example, the ammonia decomposition catalyst may be a porous spherical shape.

[0035]

[0036] In one example, the median diameter of the cross-sectional circle of the porous sphere may be about 1 to 10 mm, or about 1 mm or more, or about 2 mm or more, or about 3 mm or more, and at the same time about 10 mm or less, about 8 mm or less, about 6 mm or less, or about 4 mm or less.

[0037]

[0038] In addition, the present specification provides an ammonia decomposition method, which carries out an ammonia decomposition reaction in the presence of any one of the ammonia decomposition catalysts described above.

[0039]

[0040] In one example, the ammonia decomposition reaction may proceed at a temperature of about 400 to about 700°C, or at least about 400°C, or greater than about 400°C, or at least about 420°C, and at the same time at most about 700°C, at most about 650°C, at most about 600°C, at most about 550°C, or at most about 530°C.

[0041]

[0042] In the present invention, terms such as first, second, etc. are used to describe various components, and the terms are used only for the purpose of distinguishing one component from another.

[0043] Additionally, the terms used herein are merely used to describe exemplary embodiments and are not intended to limit the present invention.

[0044] Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0045] In this specification, the terms “comprise,” “include,” or “have” are intended to describe a feature, number, step, component, or combination thereof implemented, but do not exclude the possibility of one or more other features, numbers, steps, components, combinations, or additions thereof.

[0046] Additionally, in this specification, when each layer or element is referred to as being formed “on” or “over” each layer or element, it means that each layer or element is formed directly on each layer or element, or that other layers or elements may be additionally formed between each layer, on the object, or on the substrate.

[0047] The present invention is susceptible to various modifications and takes various forms. Specific embodiments are illustrated and described in detail below. However, this does not limit the invention to a specific disclosed form, but rather encompasses all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention.

[0048]

[0049] In addition, the porous sphere in this specification refers to a porous sphere shape, and the sphere, sphere, etc. mentioned here do not necessarily mean only a mathematically strict shape, but mean a regular or irregular shape such as a sphere, an ellipsoid, a polyhedron, etc., and a short axis / major axis value of 0.5 or more. In other words, it means a shape that is not a long shape like a stick or a greatly distorted shape. In addition, the short axis refers to the shortest value among the particle diameters measured based on the axis passing through the geometric center point of the particle, and the major axis refers to the longest value among the particle diameters measured based on the axis passing through the geometric center point of the particle.

[0050]

[0051] In addition, the total catalyst weight in this specification refers to the total weight of the carrier and the weight of the catalyst active component supported on the carrier.

[0052]

[0053] In addition, in this specification, the median pore diameter (Medium value) refers to D in particle size volume analysis. 50 In the same sense, the pore size at the point where the cumulative volume from the smallest particle size is 50% of the total particle volume of 100% is called the median pore size.

[0054]

[0055] The present specification provides an ammonia decomposition catalyst comprising a carrier and a catalytically active component supported on the carrier, wherein the catalytically active component comprises: i) a first metal, ruthenium (Ru); and ii) a second metal; and iii) a third metal; wherein the second metal and the third metal are each independently at least one selected from the group consisting of lanthanum (La), cerium (Ce), aluminum (Al), and zirconium (Zr), and the content of the first metal, ruthenium, is 0.1 to 1 part by weight based on 100 parts by weight of the total catalyst, has a porosity of 30 to 60%, and has a median pore size value of 50 to 200 μm.

[0056] Specifically, the second metal and the third metal may be different from each other.

[0057]

[0058] The inventors of the present invention discovered that when a catalyst having a specific pore distribution is prepared by coating a catalytically active component on a carrier of a specific form, such a catalyst can achieve very high efficiency as an ammonia decomposition catalyst, and thus completed the present invention.

[0059]

[0060] The ammonia decomposition reaction can be represented by the following reaction formula.

[0061]

[0062] This reaction is a reversible process, and three molecules of hydrogen gas can be obtained from two molecules of ammonia. Generally, when the reaction is carried out under high temperature and high pressure conditions in the presence of a catalyst, the forward reaction becomes dominant, and all but a trace amount of unreacted ammonia is decomposed.

[0063] However, since the above-described positive reaction is an endothermic reaction with a large difference in the energy of formation of the product and the reactant, and the activation energy of the reaction is also very high, the efficiency of the reaction is not high and a lot of energy must be input.

[0064] Accordingly, in an embodiment according to one aspect of the present invention, an ammonia decomposition reaction is performed using an ammonia decomposition catalyst comprising a carrier and a catalytically active component supported on the carrier, wherein the catalytically active component comprises: i) a first metal, ruthenium (Ru); and ii) a second metal; and iii) a third metal, wherein the second metal and the third metal are each independently at least one selected from the group consisting of lanthanum (La), cerium (Ce), aluminum (Al), and zirconium (Zr), and wherein the content of the first metal, ruthenium, is 0.1 to 1 part by weight based on 100 parts by weight of the total catalyst, has a porosity of 30 to 60%, and has a median pore diameter value of 50 to 200 μm.

[0065] Specifically, the second metal and the third metal may be different from each other.

[0066]

[0067] As a catalytically active component, ruthenium, lanthanum (La), cerium (Ce), aluminum (Al), and zirconium (Zr) can be used in the form of a composite metal oxide. Here, the composite metal oxide refers to a compound or mixture in which two or more of the metal elements mentioned as the catalytically active component are mixed with the same or different oxidation states.

[0068] That is, ruthenium, lanthanum (La), cerium (Ce), aluminum (Al), and zirconium (Zr) can be used as a catalytically active component in the form of a composite metal oxide, and among these, the metal that directly mediates the reaction is known as ruthenium, and lanthanum (La), cerium (Ce), aluminum (Al), and zirconium (Zr) can act as a kind of cocatalyst.

[0069] Specifically, the second metal may be lanthanum or cerium, and the third metal may be cerium or aluminum. Specifically, the second metal and the third metal may be different from each other. More specifically, the second metal may be lanthanum, the third metal may be cerium, or the second metal may be lanthanum, the third metal may be aluminum, or the second metal may be cerium, the third metal may be aluminum, or a combination of the second metal and the third metal.

[0070]

[0071] In addition, the ammonia decomposition catalyst according to one aspect of the present invention is in a porous form with a median pore size of 50 to 200 μm. By using a porous catalyst, not only can the surface area where the catalytically active substance can come into contact with the reactant be increased, but also thermal agglomeration of the catalytically active substance can be prevented, thereby improving the lifespan of the catalyst.

[0072] If the median pore size is too small, reactants may not flow smoothly into the catalyst pores, preventing full utilization of the active sites within the pores. This may result in reduced reaction efficiency. Conversely, if the median pore size is too large, the specific surface area of ​​the catalyst may be reduced, leading to a decrease in the dispersion of the active material, which may reduce the number of active sites and, consequently, deteriorate reaction performance.

[0073]

[0074] More specifically, the median pore size of the ammonia decomposition catalyst may be about 50 μm or more, or about 75 μm or more, or about 100 μm or more, or about 120 μm or more, or about 140 μm or more, or about 150 μm or more, and at the same time about 200 μm or less, or about 180 μm or less, or about 160 μm or less.

[0075] Within the above range, the amount of ruthenium supported on the precious metal can be minimized, while increasing the efficiency of the ammonia decomposition reaction and improving the life of the catalyst.

[0076]

[0077] In one example, the ammonia decomposition catalyst may have a porosity of about 30 to about 60%, or greater than about 10%, or greater than about 20%, or greater than about 30%, or greater than about 40%, or greater than about 50%, and at the same time, less than or equal to about 60%, or less than or equal to about 58%, or less than or equal to about 56%, or less than or equal to about 54%, or less than or equal to about 52%.

[0078] If the porosity is too low, the reactants may not be able to contact the catalytically active components within the pores, which can lead to reduced ammonia decomposition performance. Conversely, if the porosity is too high, the catalyst strength may be reduced, causing it to break during the process of filling the reactor or during the ammonia decomposition reaction, resulting in a pressure differential within the reactor. This can lead to reduced catalytic performance.

[0079]

[0080] In one example, the carrier may be a porous spherical structure.

[0081]

[0082] In one example, the carrier may be an inorganic oxide structure. More specifically, the carrier includes at least one oxide selected from the group consisting of aluminum (Al), zirconium (Zr), cerium (Ce), and silicon (Si). More specifically, the carrier may be aluminum silicate (Al2SiO5).

[0083]

[0084] According to one example, the content of the first metal may be about 0.1 to about 1 part by weight, or about 0.1 part by weight or more, or about 0.2 part by weight or more, or about 0.3 part by weight or more, or about 0.4 part by weight or more, based on 100 parts by weight of the entire catalyst, and at the same time may be about 1 part by weight or less, or about 0.9 part by weight or less, or about 0.8 part by weight or less, or about 0.7 part by weight or less, or about 0.6 part by weight or less, or 0.5 part by weight or less.

[0085] If the content of the first metal is too low, the ammonia decomposition reaction efficiency may decrease. Conversely, if the content of the first metal is too high, the active material may aggregate and the degree of dispersion may decrease, which may lower the performance of the catalyst. In addition, in order to increase the content of the first metal, the coating amount or the number of coatings may be too large during the catalyst manufacturing process, which may result in the first metal not being exposed on the catalyst surface, which may lower the catalytic efficiency. Furthermore, in the process of increasing the coating amount, the pores of the structure may be filled, which may impede the smooth flow of reactants, which may cause a pressure difference, and the specific surface area of ​​the catalyst may decrease, which may lead to a problem of lowering the performance of the catalyst. In this case, the first metal may be ruthenium.

[0086]

[0087] In one example, the ammonia decomposition catalyst may have a pore volume of about 0.1 to 0.4 mL / g, or greater than or equal to about 0.1 mL / g, or greater than or equal to about 0.2 mL / g, or greater than or equal to about 0.25 mL / g, or greater than or equal to about 0.3 mL / g, or greater than or equal to about 0.33 mL / g, and at the same time less than or equal to about 0.4 mL / g, or less than or equal to about 0.35 mL / g.

[0088] If the pore volume is too small, the active material cannot enter the pores during the process of supporting the catalyst, and the specific surface area of ​​the structure cannot be utilized, which may cause a problem of lowered catalytic performance. If the pore volume is too large, the specific surface area may be small, which may cause a problem of lowered catalytic efficiency due to a lower dispersion of the active material.

[0089]

[0090] According to one example, the content of the catalytically active component, i.e., the total amount of the first metal, the second metal, and the third metal, may be about 20 parts by weight or less, or about 0.1 parts by weight or more, or about 0.5 parts by weight or more, or about 1 part by weight or more, based on 100 parts by weight of the total catalyst, and at the same time, may be about 20 parts by weight or less, about 18 parts by weight or less, or about 15 parts by weight or less, or about 11 parts by weight or less.

[0091] If the content of the catalytically active component is too low, a problem may arise in which the efficiency of the ammonia decomposition reaction is reduced. If the content of the catalytically active component is too high, a catalytically active substance that is not exposed on the surface may be generated, which may result in a reduction in catalytic efficiency. Furthermore, a problem may arise in which the pores of the structure are blocked, which may result in a pressure difference, which may result in a reduction in catalytic performance.

[0092]

[0093] In one example, the weight ratio of (second metal):(third metal) may be from about 1:99 to about 30:70, or greater than about 1:99, or greater than about 10:90, or greater than about 20:80, or greater than about 23:77, and at the same time less than or equal to about 30:70, or less than or equal to about 25:75.

[0094]

[0095] For example, the weight ratio of (first metal):(second metal and third metal oxide) may be 1:99 to 10:90, or about 3:97 to 7:93. The catalytically active component composition formula of the present disclosure is expressed in terms of a molar ratio according to the chemical formula description method, but when actually manufacturing a catalyst, the weight ratio is measured to adjust the ratio, and therefore, the weight ratio of (first metal):(second metal and third metal oxide) corresponding to the molar ratio of the catalytically active component composition formula is as above.

[0096]

[0097] According to one embodiment of the invention, the catalytically active metal may be represented by the following chemical formula.

[0098] [chemical formula]

[0099]

[0100] In the above chemical formula, Ru is ruthenium, A is a second metal, B is a third metal, O is oxygen,

[0101] A and B are each independently at least one selected from the group consisting of lanthanum (La), cerium (Ce), aluminum (Al), and zirconium (Zr),

[0102] x is 1 to 5, more specifically, for example, 1 or more, 1.5 or more, 2 or more, or 3 or more, and at the same time 5 or less, or 4 or less, or 3.5 or less,

[0103] y is 1 to 15, more specifically, for example, 1 or more, 3 or more, 5 or more, or 10 or more, and at the same time 15 or less, 13 or less, or 11 or less,

[0104] z is 20 to 40, more specifically, for example, 20 or more, 25 or more, or 30 or more, and at the same time 40 or less, or 35 or less,

[0105] u may vary depending on the oxidation number of the above metal elements, and may be from 50 to 90, more specifically, for example, 50 or more, or 60 or more, or 70 or more, and at the same time 90 or less, or 80 or less.

[0106] Specifically, the above A and B may be different from each other.

[0107] However, in an ammonia decomposition catalyst according to an example of the present invention, the composition of each element is not necessarily limited to the above-described range.

[0108]

[0109] For example, the ammonia decomposition catalyst may be a porous sphere. The porous sphere refers to a porous sphere shape, and the sphere, sphere, etc. mentioned here do not necessarily mean only a mathematically exact shape, but mean a regular or irregular shape such as a sphere, an ellipsoid, a polyhedron, etc., and a short axis / major axis value of 0.5 or more. In other words, it means a shape that is not a long shape like a stick or a greatly distorted shape. In addition, the short axis refers to the shortest value among the particle diameters measured based on the axis passing through the geometric center point of the particle, and the major axis refers to the longest value among the particle diameters measured based on the axis passing through the geometric center point of the particle.

[0110]

[0111] In one example, the median diameter of the cross-sectional circle of the porous sphere may be about 1 to 10 mm, or about 1 mm or more, or about 2 mm or more, or about 3 mm or more, and at the same time about 10 mm or less, about 8 mm or less, about 6 mm or less, or about 4 mm or less.

[0112] If the median diameter of the cross-sectional circle of the porous sphere is too large, the packing density will be low, causing the reactants to bypass and not come into contact with the catalyst, which can lead to a decrease in catalytic efficiency. Conversely, if the median diameter of the cross-sectional circle of the porous sphere is too small, the packing density will be high, resulting in a pressure differential, which can lead to a decrease in reaction efficiency.

[0113]

[0114] The above-mentioned catalyst can be prepared by the following method.

[0115]

[0116] First, an aqueous solution of a ruthenium salt is prepared. Examples of the aqueous solution of a ruthenium salt include an aqueous solution of ruthenium fluoride, an aqueous solution of ruthenium chloride, an aqueous solution of ruthenium nitrate, an aqueous solution of ruthenium sulfate, and an aqueous solution of perruthenate ions.

[0117] Then, the second metal-third metal oxide powder is added here, and basic conditions are created using ammonia water, etc. This is filtered and washed, and dried in an oven at about 100 to about 150°C for about 6 to about 20 hours to obtain a powder.

[0118] The powder obtained here is added to distilled water, a zirconia ball is added, and the mixture is stirred with a roller to prepare a slurry.

[0119] Here, a support is impregnated and coated, and the filtrate is removed, and then dried in an oven at about 100 to about 150°C for about 6 to about 20 hours. The weight of the dried sample is measured to determine the amount of the coated catalytically active component. By repeating the process of coating the support with a slurry solution and drying as many times as desired, a supported catalyst in which the first, second, and third metals described above are supported on the support can be obtained.

[0120]

[0121] Meanwhile, the supported catalyst manufactured by the above method can be used as an ammonia decomposition catalyst as is, or can be used as an ammonia decomposition catalyst by calcining or reducing it.

[0122]

[0123] During calcination and reduction, calcination and reduction conditions generally used in the technical field to which the present invention belongs can be employed, such as treating the catalyst obtained above with hydrogen gas at a temperature of about 300 to about 600°C.

[0124]

[0125] In addition, the present specification provides an ammonia decomposition method, which carries out an ammonia decomposition reaction in the presence of any one of the ammonia decomposition catalysts described above.

[0126]

[0127] In an ammonia decomposition method according to an example of the present invention, in addition to using a catalyst according to an example of the present invention, reaction conditions generally used in the technical field to which the present invention belongs can be employed.

[0128]

[0129] In one example, the ammonia decomposition reaction may proceed at a temperature of about 400 to about 700°C, or at least about 400°C, or greater than about 400°C, or at least about 420°C, and at the same time at most about 700°C, at most about 650°C, at most about 600°C, at most about 550°C, or at most about 530°C.

[0130]

[0131] According to another example, the ammonia decomposition reaction may proceed after purging using an inactive gas or the like before the full-scale reaction.

[0132]

[0133] And during the reaction, the shape of the reactor is not particularly limited, and a suitable shape of reactor that can directly contact the catalyst and the reactant by blowing ammonia gas into the catalyst of the above-mentioned shape can be selected and used.

[0134]

[0135] The present specification can provide an ammonia decomposition catalyst having excellent low-temperature decomposition performance at high space velocity.

[0136] In addition, the present specification can provide an ammonia decomposition catalyst that can prevent catalytic thermal agglomeration, thereby providing reaction process stability and having an improved lifespan.

[0137] In addition, the present specification can provide an ammonia decomposition method using such an ammonia decomposition catalyst.

[0138]

[0139] Figure 1 illustrates a porous spherical structure used in one embodiment of the present invention.

[0140] Figure 2 illustrates a catalyst loaded with an active ingredient of one embodiment of the present invention.

[0141] Figure 3 shows a catalyst of a comparative example of the present invention.

[0142] Figure 4 shows a catalyst of a comparative example of the present invention.

[0143] Figure 5 illustrates a graph of the pore size distribution between a porous spherical structure of an experimental example of the present invention and Example 1 containing an active ingredient.

[0144] Figure 6 shows a graph of the NH3 conversion rate of the catalyst of Example 1 according to the catalyst layer temperature of one experimental example of the present invention.

[0145]

[0146] Hereinafter, the functions and effects of the invention will be described in more detail through specific examples. However, these examples are provided merely as examples of the invention and do not define the scope of the invention.

[0147]

[0148] Example 1

[0149] As a source of metal components, an aqueous solution of ruthenium chloride and LaCeria synthesized using a coprecipitation method were used.

[0150] 20 g of LaCeria was added to a ruthenium chloride aqueous solution prepared by considering the content of each metal element in the catalytic active ingredient, and the pH was adjusted to 9 using ammonia water.

[0151] The above solution was stirred for 18 hours using a stirrer and a magnetic bar. The resulting liquid was filtered and washed with water until it became neutral, then placed in an oven at 110°C and dried for approximately 12 hours to obtain a powder catalyst.

[0152] A catalyst solution was prepared by adding 18 g of the powder catalyst obtained above and 1.8 g of Boehmite to 72 mL of distilled water. 360 g of zirconia balls with a diameter of 5 mm or less were added thereto, and milling was performed on a roller at 200 rpm for approximately 6 hours to control the particle size in the catalyst solution. To dissolve Boehmite and use it as a binder, a 60% nitric acid solution was used to adjust the pH to 3.5.

[0153] After impregnating about 50 g of a 3.2 mm sized porous spherical structure (material: aluminum silicate ball; manufacturer: Saint-Gobain Norpro; product name: SA52252) as a support into the above catalyst solution, the filtrate was removed using an air gun.

[0154] This was placed in an oven at about 110°C and dried for about 6 hours.

[0155] The impregnation and drying of the support in the catalyst solution were repeated until 10 parts by weight out of the total 100 parts by weight of the coated catalyst became a powder catalyst. As a result, a molded catalyst having a catalytically active component coated on the surface of a porous spherical structure was obtained.

[0156]

[0157] The metal components, which are active components in the obtained catalyst material, were analyzed using ICP-OES, and the structural changes in the support were confirmed through Hg porosity.

[0158]

[0159] Examples 2 to 3

[0160] A supported catalyst was obtained by proceeding in the same manner as in Example 1, except that the number of coatings was varied and the amount of catalytically active material supported was varied.

[0161]

[0162] Example 4

[0163] A supported catalyst was obtained in the same manner as in Example 1, except that commercial LaAlOx (manufacturer: Sasol; product name: TH100 / 150 / L10) was used instead of LaCeria synthesized using the coprecipitation method.

[0164]

[0165] Example 5

[0166] A supported catalyst was obtained in the same manner as in Example 1, except that commercial CeAlOx (manufacturer: Sasol; product name: TH100 / 150 / Ce20) was used instead of LaCeria synthesized using the coprecipitation method.

[0167]

[0168] Example 6

[0169] A supported catalyst was obtained by performing the same procedure as in Example 1, such as the number of supports and the amount of supports, except that the concentration of the ruthenium aqueous solution was increased by 2.4 times to increase the Ru content in the powder catalyst by about 2.4 times.

[0170]

[0171] Example 7

[0172] A supported catalyst was obtained in the same manner as in Example 1, except that a porous spherical structure with a size of 4.8 mm (Material: Aluminum silicate ball; Manufacturer: Saint-Gobain Norpro; Product name: SA52252) was used as a support and the number of support cycles was 5 to obtain the same support amount as in Example 1.

[0173]

[0174] Example 8

[0175] A supported catalyst was obtained in the same manner as in Example 1, except that a porous spherical structure with a size of 6.1 mm (Material: Aluminum silicate ball; Manufacturer: Saint-Gobain Norpro; Product name: SA52252) was used as a support and the number of times of support was 6 to exhibit the same support amount as in Example 1.

[0176]

[0177] Comparative Example 1

[0178] A supported catalyst was obtained in the same manner as in Example 1, except that the number of coatings (number of supports) was changed to 10 and the amount of catalytically active material supported was changed as shown in Table 1.

[0179]

[0180] Comparative examples 2 and 3

[0181] In the case of Comparative Example 2, the same procedure as in Examples 1, 2, 3 and Comparative Example 1 was followed, but without carrying out the support, the obtained powder itself was molded and manufactured into a catalyst.

[0182] In the case of Comparative Example 3, the same procedure as in Examples 1, 2, 3 and Comparative Example 1 was followed, but the catalyst was supported on a ceramic hollow cylinder (Material: Ceramic rings; Manufacturer: Saint-Gobain NorPro; Product Name: SA5518) in the shape of a cylinder with an empty middle until 13 wt% of the coating catalyst became a powder catalyst.

[0183]

[0184] Comparative Example 4

[0185] A supported catalyst was obtained in the same manner as in Example 1, except that 21.5 g of powdered catalyst was added during catalyst milling to increase the viscosity of the catalyst solution.

[0186]

[0187] Information about the obtained catalyst is summarized in Table 1 below.

[0188]

[0189] Catalyst composition Catalyst form Ru amount (unit: wt%) Active ingredient composition Number of times supported (times) Support amount (wt%) Support amount (wt%) Shape Spherical Cross-sectional diameter (mm) Example 10.29Ru 1.8 / La 10.3 Ce 24.1 O 63.8 41189 Old Type 3.2 Example 20.39Ru 1.8 / La 10.3 Ce 24.1 O 63.8 61585 Old Type 3.2 Example 30.52Ru 1.8 / La 10.3 Ce 24.1 O 63.8 82080 Old Type 3.2 Example 40.29Ru 0.7 / La 1.3 Al 38.4 O 59.6 41090 Old Type 3.2 Example 50.30Ru 0.7 / Ce 2.7 Al 36.5 O 60.1 41090 Old Type 3.2 Example 60.68Ru 4.1 / La 10.1 Ce 23.6 O 62.3 41090 Old Type 3.2 Example 70.30Ru 1.8 / La 10.3 Ce 24.1 O 63.8 51090 Old Type 4.8 Example 80.30Ru 1.8 / La 10.3 Ce 24.1 O 63.8 61090 Old 6.1 Comparison Example 10.69Ru 1.8 / La 10.3 Ce 24.1 O 63.8 102476 Old 3.2 Comparison Example 22.22Ru 3.5 / La 6.2 Ce 20.7 O 70 -1000 polygons 1~3 comparison example 30.37Ru 3.5 / La 6.2 Ce 20.7 O 70 61882 Hollow cylinder Outer diameter: 4.4, Inner diameter: 1.2 Comparative example 40.30Ru 1.8 / La 10.3 Ce24.1 O 63.8 31189 Old 3.2

[0190]

[0191] Pore ​​characteristic analysis

[0192] The pore characteristics of the catalysts manufactured in the above examples and comparative examples were analyzed according to the mercury pore analysis method (ASTM D4284) using a mercury pressure pore distribution measuring device (manufacturer: Micromeritics; model name: AutoPoreⅤ).

[0193] After placing an appropriate amount of sample into the sample cell without a separate pretreatment process, the pore volume was measured by pressurizing the sample within the catalyst pores at a pressure ranging from 0.2 to 33,000 psi to force mercury into the catalyst pores. The average particle diameter obtained from the analysis was used as the median pore diameter value.

[0194] The analysis results are summarized in Table 2 below.

[0195] Classification Pore properties Median pore size (㎛) Pore volume (mL / g) Porosity (%) Median pore size / Porosity Example 1 280.285 12.51 Example 2 1440.335 82.48 Example 3 1520.325 52.76 Example 4 1290.295 22.48 Example 5 1280.295 12.51 Example 6 1280.285 12.51 Example 7 1380.315 52.51 Example 8 1590.305 72.79 Comparative example 1 4440.335 77.79 Comparative example 20.04 0.015 0.07 0.57 Comparative example 37 30.09 243.04 Comparative example 4 450.185 30.85

[0196] In addition, the results of the pore characteristic analysis of the porous spherical structure used as a carrier and the catalyst of Example 1 loaded with the active ingredient are shown in Table 3 and Fig. 5.

[0197] The measurement method was the same as the above mercury porosity analysis method.

[0198] Physical properties Distribution of support Example 1 Pore volume (mL / g) 0.29 0.28 Bulk density (g / mL) 1.72 1.82 Apparent density (g / mL) 3.46 3.67 Median pore size (㎛) 119.10 12 7.80 Porosity (%) 50.40 50.50

[0199] As a result of the verification, it was confirmed that the pore characteristics of the support did not change significantly even when the catalyst was supported.

[0200]

[0201] Ammonia decomposition reaction

[0202] Each of the catalysts manufactured in the above examples and comparative examples was taken in an amount of 3 g, charged into an OD 1 / 2" reactor, heated to 350°C using nitrogen gas, and then reduced by flowing a hydrogen / nitrogen mixture gas (50v%) at that temperature for about 1 hour.

[0203] The catalyst subjected to reduction treatment above was purged in a nitrogen atmosphere at about 350°C for about 30 minutes, and 99% ammonia gas was injected at a high space velocity (GHSV, Gas hourly space velocity) of 4000 h. -1 The temperature of the reaction system was increased to approximately 400 ℃ while flowing at a rate of , and the temperature was increased at 50 ℃ intervals, and the ammonia decomposition rate up to 550 ℃ was analyzed.

[0204] The analysis results are summarized in Table 4 below.

[0205] The conversion rate was calculated by analyzing the outlet gas discharged from the reactor using gas chromatography, calculating the volume ratio (n) of NH3 to the total volume of discharged gas, and calculating the conversion rate = (1-n) / (1+n).

[0206] The catalyst pressure differential characteristics were measured by installing pressure transmitters at the front and rear ends of the reactor and calculating the pressure difference between the front and rear ends.

[0207] The catalyst layer temperature difference is the temperature difference between the furnace temperature used to heat the reactor and the temperature inside the catalyst layer, and was measured by inserting a thermocouple (TC) in the middle of the catalyst layer.

[0208] The activity per gRu was calculated as (flow rate of ammonia injected) * conversion rate / 22.4 / (mass of Ru in the loaded catalyst).

[0209] NH3 conversion rate (%) according to temperature Catalyst pressure difference characteristics Catalyst bed temperature difference Activity per gRu @ 400°C @ 450°C @ 500°C @ 550°C @ 500°C @ 500°C mmol NH3 / gRu / min, @ 500°C Example 1 17.94 2.17 8.09 9.10 140 72 1.6 Example 2 20.44 7.18 2.99 9.40 165 56 1.7 Example 3 23.65 0.98 5.99 9.60 165 39 5.5 Example 4 18.14 3.28 0.39 9.40 143 74 2.9 Example 5 18.04 2.97 9.89 9.30 142 738 2 Example 6 34.56 7.29 9.2 -0.16 8391.4 Example 718.042.378.299.2-40723.5 Example 817.842.378.199.2-41722.5 Comparative Example 126.555.789.299.70.167290.0 Comparative Example 218.040.077.889.20.33894.0 Comparative Example 35.417.251.0-0.932369.8 Comparative Example 410.230.255.788.80.738498.1

[0210] It was confirmed that Examples 1 to 8 had superior activity per gRu, i.e., the same ruthenium sugar activity, compared to Comparative Examples 1 to 3.

[0211] In particular, in the case of Comparative Example 1, although the pore characteristics such as pore volume and porosity were similar to those of the Examples, it was confirmed that the activity per gRu was significantly inferior to that of the Examples. In particular, the reason why the median pore diameter was large was because the coating amount of the catalyst of Comparative Example 1 was greater than that of the Examples, so that small pores in the 100 μm range were blocked by the catalyst coating and only large pores remained, and the pores of the support could not be utilized due to excessive catalyst coating. As a result, the activity per gRu was inferior to that of the Examples.

[0212] In addition, the catalyst according to the example was measured to have a low pressure difference between the upstream and downstream ends of the reactor, i.e., differential pressure. On the other hand, Comparative Examples 3 and 4 showed high differential pressures of 0.9 and 0.7, respectively. This means that the gas flow in the catalyst-filled section of the reactor was not as smooth as in the example, resulting in a significant decrease in catalytic performance throughout the entire reaction flow, regardless of the activity per gRu.

[0213] In addition, when comparing Example 6 and Comparative Example 1, the weight ratio of Ru included in the catalyst is similar, but the number of times of loading is different, 4 times in Example 6 and 10 times in Comparative Example 1, and it is understood that the catalytic activity is different accordingly. As can be seen from the median pore diameter of Comparative Example 1, it is thought that as the number of times of loading increases, small pores become blocked, and thus the catalyst trapped in the pores cannot participate in the reaction.

[0214] In Comparative Example 3, the conversion rate at 550°C could not be measured because the reaction could not proceed at 550°C due to a large differential pressure.

[0215] Comparative Example 4 was performed in the same manner as Example 1, except that 21.5 g of powdered catalyst was added during milling to increase the viscosity of the catalyst solution. As a result, the median pore size became excessively small and the pore volume also became small. In addition, as the median pore size became excessively small, the differential pressure also became large and the catalytic performance also appeared inferior.

Claims

1. A carrier, and a catalytically active component supported on the carrier, The above catalytically active component comprises i) a first metal, ruthenium (Ru); and ii) a second metal; and iii) a third metal; The second metal and the third metal are each independently at least one selected from the group consisting of lanthanum (La), cerium (Ce), aluminum (Al), and zirconium (Zr), The content of the first metal, ruthenium, is 0.1 to 1 part by weight based on 100 parts by weight of the total catalyst, The porosity is 30 to 60%, The median pore size (median value) is 50 to 200 ㎛, Ammonia decomposition catalyst.

2. In paragraph 1, having a pore volume of 0.1 to 0.4 mL / g, Ammonia decomposition catalyst.

3. In paragraph 1, The above carrier is a porous spherical structure, Ammonia decomposition catalyst.

4. In paragraph 1, The above carrier is an inorganic oxide structure, Ammonia decomposition catalyst.

5. In paragraph 1, An ammonia decomposition catalyst in which the content of the above catalytic active ingredient is 20 parts by weight or less based on 100 parts by weight of the entire catalyst.

6. In paragraph 1, An ammonia decomposition catalyst having a weight ratio of (second metal):(third metal) of 1:99 to 30:

70.

7. In paragraph 1, An ammonia decomposition catalyst having a weight ratio of (first metal):(second metal and third metal oxide) of 1:99 to 10:

90.

8. In paragraph 1, Porous sphere, Ammonia decomposition catalyst.

9. In paragraph 8, An ammonia decomposition catalyst having a median diameter of the cross-sectional circle of the porous sphere of the above-mentioned type of ammonia.

10. A method for decomposing ammonia, wherein an ammonia decomposition reaction is performed in the presence of an ammonia decomposition catalyst according to any one of claims 1 to 9.

11. In paragraph 10, A method for decomposing ammonia, which is carried out at 400 to 700 ℃.

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