Dehydrogenation catalyst, pyrolysis tube for olefin production, and method for producing olefins

Abstract

To realize a dehydrogenation catalyst with high catalytic capacity in a thermal cracking reaction of hydrocarbon raw material.SOLUTION: A dehydrogenation catalyst (4) is represented by the general formula M1M2Ox, where the M1 is at least one element selected from a first group consisting of Y, Ce, La, Pr, Gd, Sm, Eu, V, and Zr, and the M2 is at least one element selected from a second group consisting of Cr, Fe, Mn, Co, and V.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] This invention relates to dehydrogenation catalysts and the like. [Background technology]

[0002] Olefins such as ethylene and propylene are used in industry to manufacture a wide variety of chemically synthesized products. Olefins are produced by flowing petroleum-derived hydrocarbons such as ethane and naphtha through a cracking tube and heating it to 700-900°C to thermally decompose it in the gas phase. This manufacturing method requires a large amount of energy to reach high temperatures. Therefore, a technique is known in which a dehydrogenation catalyst is supported on the inner surface of the cracking tube.

[0003] Patent Document 1 discloses a dehydrogenation catalyst that includes, as a catalytic component, at least one of the group consisting of oxides of metal elements from Group 2B, Group 3B, and Group 4B of the periodic table. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2017-209661 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, the dehydrogenation catalyst described in Patent Document 1 may not provide sufficient performance depending on the olefin production conditions, and further development of dehydrogenation catalysts is desired.

[0006] One aspect of the present invention has been made in view of the above-mentioned problems, and its object is to provide a dehydrogenation catalyst with high catalytic activity in the thermal decomposition reaction of hydrocarbon raw materials. [Means for solving the problem]

[0007] In order to solve the above problems, a dehydrogenation catalyst according to one aspect of the present invention has the general formula M1M2O x and is represented by the formula, wherein M1 is at least one element selected from the first group consisting of Y, Ce, La, Pr, Gd, Sm, Eu, V, and Zr, and M2 is at least one element selected from the second group consisting of Cr, Fe, Mn, Co, and V.

Effect of the Invention

[0008] According to one aspect of the present invention, a dehydrogenation catalyst having high catalytic activity in the thermal decomposition reaction of hydrocarbon raw materials can be realized.

Brief Description of the Drawings

[0009] [Figure 1] It is a schematic cross-sectional view showing the configuration of a pyrolysis tube for olefin production according to Embodiment 1 of the present invention. [Figure 2] It is an enlarged view of the inner surface of the pyrolysis tube for olefin production. [Figure 3] It is a schematic cross-sectional view showing the configuration of a pyrolysis tube for olefin production according to Embodiment 2 of the present invention. [Figure 4] It is an enlarged view of the inner surface of the pyrolysis tube for olefin production.

Modes for Carrying Out the Invention

[0010] 〔Embodiment 1〕 Hereinafter, the pyrolysis tube 1A for olefin production and the dehydrogenation catalyst 4 in Embodiment 1 of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing the configuration of the pyrolysis tube 1A for olefin production in the present embodiment. FIG. 2 is an enlarged view of the inner surface of the pyrolysis tube 1A for olefin production.

[0011] ​As shown in FIGS. 1 and 2, for the pyrolysis tube 1A for olefin production, an alumina film 3 is formed on the inner surface of the surface of the tubular base material 2 and the plate-like body (insert material) 5. The base material 2 and the plate-like body 5 are made of a heat-resistant metal material. The alumina film 3 is a metal oxide film containing Al2O3. A dehydrogenation catalyst 4 is supported on the surface of the alumina film 3. In the present application, a metal oxide film containing Al2O3 is referred to as an "alumina film". By having the above configuration, in the pyrolysis tube 1A for olefin production, the dehydrogenation catalyst reaction is added to the pyrolysis reaction, so that the olefin yield from hydrocarbon raw materials such as ethane and naphtha can be improved. Hereinafter, the base material 2, the plate-like body 5, the alumina film 3, and the dehydrogenation catalyst 4 in the pyrolysis tube 1A for olefin production will be described in detail.

[0012] (Base material 2 and plate-like body 5) The base material 2 in the present embodiment is a casting made of a heat-resistant metal material with an alumina film 3 formed on the surface of the base material 2. The plate-like body 5 in the present embodiment is provided inside the base material 2 and is a casting or a stainless steel plate made of a heat-resistant metal material with an alumina film 3 formed on the surface of the plate-like body 5. In the present embodiment, the pyrolysis tube 1A for olefin production includes the plate-like body 5, but the plate-like body 5 is not an essential member and may not be provided. The base material 2 and the plate-like body 5 may be, for example, castings of conventionally known heat-resistant metal materials, and it is preferable that they are castings made of heat-resistant metal materials containing at least chromium (Cr), nickel (Ni), and aluminum (Al).

[0013] In the present embodiment, the alumina film 3 is formed on the inner surface of the base material 2 and the surface of the plate-like body 5, but the alumina film 3 may be formed only on the inner surface of the base material 2, or the alumina film 3 may be formed only on the surface of the plate-like body 5. Also, in the present embodiment, the dehydrogenation catalyst 4 is supported on the inner surface of the base material 2 and the surface of the plate-like body 5, but the dehydrogenation catalyst 4 may be supported only on the inner surface of the base material 2, or the dehydrogenation catalyst 4 may be supported only on the surface of the plate-like body 5.

[0014] Preferably, at least a portion of the inner surface of the base material 2 and / or the surface of the plate-like body 5 constitutes recesses and / or protrusions. This improves heat transfer efficiency and allows for uniform heating of the fluid inside the tubular base material 2.

[0015] (Alumina coating 3) The alumina coating 3 is highly dense and acts as a barrier to prevent oxygen, carbon, and nitrogen from entering the base material 2 and plate-like body 5 from the outside. In typical pyrolysis tubes for olefin production, no metal oxide coating is formed on the inner surface of the base material 2 and the surface of the plate-like body 5. Therefore, excessive decomposition of hydrocarbon raw materials occurs during pyrolysis due to the catalytic action of constituent elements such as nickel (Ni), iron (Fe), and cobalt (Co) on the surfaces of the base material 2 and plate-like body 5, resulting in the formation of coke on the inner surface of the base material 2 and the surface of the plate-like body 5. When coke accumulates on the inner surface of the base material 2 and the surface of the plate-like body 5, the heat transfer resistance increases, causing the temperature of the outer surface of the pyrolysis tube for olefin production to rise in order to maintain the reaction temperature inside the olefin pyrolysis tube. In addition, when coke accumulates on the inner surface of the base material 2 and the surface of the plate-like body 5, the cross-sectional area of ​​the gas passage decreases, leading to increased pressure loss. For these reasons, typical pyrolysis tubes used in olefin production required frequent removal (decoking) of accumulated coke.

[0016] In contrast, in the olefin production pyrolysis tube 1A of this embodiment, the formation of an alumina film 3 on the inner surface of the base material 2 and the surface of the plate-like body 5 suppresses the formation of coke on the inner surface of the base material 2 and the surface of the plate-like body 5. As a result, the frequency of decoking can be reduced.

[0017] The alumina film 3 of the present invention is formed by a surface treatment step and a first heat treatment step. The surface treatment step is a step of performing surface treatment on the target parts of the base material 2 and plate-like body 5 that come into contact with a high-temperature atmosphere during product use, thereby adjusting the surface roughness of those parts. Polishing can be an example of the surface treatment of the base material 2 and plate-like body 5. The surface treatment can be carried out so that the surface roughness (Ra) of the target parts becomes 0.05 to 2.5 μm. More preferably, the surface roughness (Ra) is 0.5 to 2.0 μm. Furthermore, by adjusting the surface roughness through surface treatment, residual stress and strain in the heat-affected zone can also be removed at the same time.

[0018] The first heat treatment step involves heat-treating the base material 2 and plate-like body 5 after the surface treatment step in an oxidizing atmosphere. The oxidizing atmosphere is an oxidizing gas containing 20% ​​or more by volume of oxygen, or an oxidizing environment mixed with steam or CO2. The heat treatment is carried out at a temperature of 900°C or higher, preferably 1000°C or higher, for a heating time of 1 hour or more.

[0019] As described above, by sequentially performing a surface treatment step and a first heat treatment step on the base material 2 and the plate-like body 5, it is possible to manufacture a pyrolysis tube for olefin production in which an alumina film 3 is stably formed on the inner surface of the base material 2 and the surface of the plate-like body 5.

[0020] The thickness of the alumina film 3 formed on the inner surface of the base material 2 and the surface of the plate-like body 5 is preferably 0.5 μm to 6 μm in order to effectively exhibit the barrier function. If the thickness of the alumina film 3 is less than 0.5 μm, there is a risk that the carburization resistance will decrease. If the thickness of the alumina film 3 exceeds 6 μm, there is a risk that the alumina film 3 will be prone to peeling due to the difference in thermal expansion coefficients between the base material 2 and the plate-like body 5 and the film. For the reasons above, the alumina film The thickness of film 3 is more preferably 0.5 μm or more and 2.5 μm or less.

[0021] Furthermore, a chromium oxide scale may partially form on the alumina film 3. This is because the chromium oxide scale formed near the surface of the base material 2 and the plate-like body 5 is pushed up to the product surface by Al2O3. It is preferable to have as little of this chromium oxide scale as possible, and it is preferable to have it cover less than 20 area of ​​the product surface, while Al2O3 covers 80 area or more.

[0022] (Dehydrogenation catalyst 4) Dehydrogenation catalyst 4 is a dehydrogenation catalyst used in olefin production. Dehydrogenation catalyst 4 is a catalyst for improving the yield of olefins in the thermal decomposition reaction using the olefin production pyrolysis tube 1A (specifically, a reaction in which hydrocarbon raw materials such as naphtha and ethane are thermally decomposed into olefins), and is supported on the surface of the alumina film 3.

[0023] The dehydrogenation catalyst 4 has the general formula M1M2O x Represented as follows, where M1 is at least one element selected from the first group consisting of Y, Ce, La, Pr, Gd, Sm, Eu, V, and Zr, and M2 is at least one element selected from the second group consisting of Cr, Fe, Mn, Co, and V. The above x is 2 or 3.

[0024] Due to the above configuration, the dehydrogenation catalyst 4 can easily add and remove oxygen from its structure. As a result, the dehydrogenation catalyst 4 can promote the dehydrogenation reaction of hydrocarbon raw materials and therefore has high catalytic activity in the dehydrogenation reaction.

[0025] A dehydrogenation catalyst 4 according to one aspect of the present invention comprises a plurality of elements included in the first group, and the plurality of elements may include at least Y, Ce, Pr, or La.

[0026] The dehydrogenation catalyst 4 according to one embodiment of the present invention may contain at least Y as the above M1. The dehydrogenation catalyst 4 according to one embodiment of the present invention may contain at least either Y or Zr as the above M1. The dehydrogenation catalyst 4 according to one embodiment of the present invention may contain at least Cr as the above M2. The dehydrogenation catalyst 4 according to one embodiment of the present invention may contain at least Zr as the above M1. Further, the dehydrogenation catalyst 4 according to one embodiment of the present invention may contain Y and Zr as the above M1. According to this configuration, the catalytic ability in the dehydrogenation reaction can be further enhanced. Also, when the dehydrogenation catalyst 4 according to one embodiment of the present invention contains Y and Zr as the above M1, it can be represented by the general formula Y 1-y Zr y M2O x In this case, it may contain at least Cr as the above M2. Also, when the dehydrogenation catalyst 4 according to one embodiment of the present invention contains Y and Zr as the above M1, it is represented by the general formula Y 1-y Zr y M2O x and the above y may satisfy 0 ≦ y ≦ 1.5. According to this configuration, the coke generated on the surface of the alumina film 3 can be gasified. As a result, the amount of coke deposited on the surface of the alumina film 3 can be reduced, so that the frequency of decoking can be reduced. Also, when the dehydrogenation catalyst 4 according to one embodiment of the present invention contains Y and Zr as the above M1, it is represented by the general formula Y 1-y Zr y M2O x and the above y satisfies 0 ≦ y ≦ 0.15, and it may have two elements included in the above second group as the above M2. Also, when the dehydrogenation catalyst 4 according to one embodiment of the present invention contains Y and Zr as the above M1, it is represented by the general formula Y 1-y Zr y M2O x and the above y may satisfy 0 < y ≦ 0.1.

[0027] Furthermore, the dehydrogenation catalyst 4 in one embodiment of the present invention may contain at least Y as M1 and at least Cr as M2. This configuration allows for even higher catalytic activity in the dehydrogenation reaction.

[0028] Furthermore, the dehydrogenation catalyst 4 in one embodiment of the present invention may contain Y, Pr, La, or Ce as M1. By including Y, Pr, La, or Ce, the water (H2O) adsorbed on the surface of the dehydrogenation catalyst 4 can be activated. The activated water reacts with the coke (C) precursor attached to the surface of the dehydrogenation catalyst 4 and is gasified as carbon monoxide (CO) or carbon dioxide (CO2). As a result, the amount of coke deposited on the surface of the alumina film 3 can be reduced, and therefore the frequency of decoking can be reduced.

[0029] <Method for producing dehydrogenation catalyst 4> The method for producing the dehydrogenation catalyst 4 is not particularly limited, but it can be produced by, for example, a citric acid complex polymerization method or a solid-phase method. The following describes methods for producing the dehydrogenation catalyst 4 using a citric acid complex polymerization method and a solid-phase method.

[0030] (Citrate complex polymerization method) The citric acid complex polymerization method includes a mixing and stirring step, a drying step, a calcination step, and a final calcination step.

[0031] In the mixing and stirring step, a salt containing the elements constituting the dehydrogenation catalyst 4 (e.g., nitrate or acetate), citric acid monohydrate, ethylene glycol, and distilled water are mixed to obtain a mixture. The salt is weighed so that the elements of Group 1 and Group 2 are in the desired molar ratio. It is preferable to add citric acid monohydrate in an amount 3 to 4 times the total molar amount of Group 1 and Group 2 elements contained in the salt. It is preferable to add ethylene glycol in an amount 3 to 4 times the total molar amount of Group 1 and Group 2 elements contained in the salt. It is preferable to add distilled water in an amount 1200 to 1600 times the total molar amount of Group 1 and Group 2 elements contained in the salt. The mixture is preferably stirred at 60 to 70°C for 10 to 17 hours.

[0032] In the drying process, the mixture is dried to obtain a powder. For example, this can be done by heating and drying it on a hot plate while stirring.

[0033] In the calcination process, the powder is calcined to obtain a calcined body. The calcination process is carried out in air or oxygen, and the calcination temperature is preferably 400-450°C, with a holding time of 2-3 hours. The calcination temperature and holding time can be appropriately adjusted within this range depending on the amount of catalyst being prepared.

[0034] In the main calcination process, the calcined body is calcined to obtain an oxide. The main calcination process is carried out in air or oxygen, and the calcination temperature is preferably 850 to 900°C, with a holding time of 8 to 12 hours. The calcination temperature and holding time can be appropriately adjusted within this range depending on the amount of catalyst being prepared.

[0035] (solid phase method) The solid-phase method includes a grinding and mixing step, a drying step, and a calcination step.

[0036] In the grinding and mixing step, a compound containing the elements that make up the dehydrogenation catalyst 4 (e.g., oxides, carbonates) is mixed, and the mixture is ground and mixed to obtain a ground and mixed powder. The compound is mixed so that the elements of group 1 and group 2 are in the desired molar ratio. For example, this can be done by grinding and mixing using a wet bead mill.

[0037] In the drying process, the pulverized and mixed powder is dried to obtain a dried product. In the calcination process, the dried product is calcined to obtain an oxide. The calcination process is carried out in air or oxygen, and the calcination temperature is preferably 500 to 1300°C, with a holding time of 1 to 10 hours. The calcination temperature and holding time can be appropriately adjusted within this range depending on the amount of catalyst being prepared.

[0038] <Method for supporting dehydrogenation catalyst 4> Next, the method for supporting the dehydrogenation catalyst 4 onto the alumina film 3 will be described. The method for supporting the dehydrogenation catalyst 4 onto the alumina film 3 includes a coating step and a second heat treatment step. The coating step and the second heat treatment step will be described in detail below.

[0039] (a) Coating process The coating step involves applying a slurry containing a pre-prepared dehydrogenation catalyst 4 to the surface of the alumina film 3 formed by the surface treatment step and the first heat treatment step.

[0040] (b) Second heat treatment process The second heat treatment step is a step of heat-treating the base material 2 and plate-shaped body 5, which have the slurry applied to the alumina film 3 by the coating step.

[0041] The heat treatment in the second heat treatment step is carried out in air or an acidic atmosphere. The heat treatment temperature in the second heat treatment step is in the range of 500 to 900°C, and the heat treatment time is 1 to 6 hours.

[0042] By performing the second heat treatment step under the aforementioned heat treatment conditions, the dehydrogenation catalyst 4 can be supported on the alumina film 3.

[0043] Furthermore, by adjusting the concentration of the slurry applied in the aforementioned coating step, the dehydrogenation catalyst 4 can be supported on the alumina film 3 at an appropriate concentration (amount).

[0044] As described above, in this embodiment, the pyrolysis tube 1A for olefin production has an alumina film 3 formed on the inner surface of a tubular base material 2 made of a heat-resistant metal material and on the surface of a plate-like body 5, and a dehydrogenation catalyst 4 is supported on the surface of the alumina film 3.

[0045] According to the above configuration, the pyrolysis tube 1A for olefin production of the present invention has an alumina coating 3 formed on the inner surface of the base material 2 and on the surface of the plate-like body 5. This suppresses the formation of coke on the surface of 2 and the plate-like body 5). Furthermore, a dehydrogenation catalyst 4 is supported on the surface of this alumina film 3. As a result, when the dehydrogenation catalyst 4 acts as a dehydrogenation catalyst in thermal decomposition using the olefin production thermal decomposition tube 1A, it is possible to produce ethylene from ethane, for example, through a dehydrogenation reaction. Consequently, the yield of olefins from hydrocarbon raw materials such as ethane and naphtha by thermal decomposition can be improved.

[0046] Furthermore, in this embodiment, the dehydrogenation catalyst 4 was supported on the alumina film 3 formed on the inner surface of the base material 2 and the surface of the plate-like body 5 by the surface treatment step and the first heat treatment step, by performing a coating step and a second heat treatment step. However, the pyrolysis tube for olefin production of the present invention is not limited to this. For example, the coating step and heat treatment step may be performed after the surface treatment step. In this case, during the heat treatment step, the alumina film 3 is formed on the inner surface of the base material 2 and the surface of the plate-like body 5, and the dehydrogenation catalyst 4 is supported on the alumina film 3. As a result, the alumina film 3 can be formed on the inner surface of the base material 2 and the surface of the plate-like body 5, and the dehydrogenation catalyst 4 can be supported on the alumina film 3 by performing the heat treatment step only once.

[0047] Furthermore, in this embodiment, the dehydrogenation catalyst 4 was supported on the surface of the alumina film 3 formed on the inner surface of the base material 2 and the surface of the plate-like body 5. However, the pyrolysis tube 1A for olefin production of the present invention is not limited to this. That is, the pyrolysis tube for olefin production of the present invention may be configured such that the dehydrogenation catalyst 4 is supported on the surface of a metal oxide film other than Al2O3 (for example, Cr2O3, MnCr2O4, etc.) which has a barrier function and can support the dehydrogenation catalyst 4.

[0048] A method for producing olefins according to one aspect of the present invention is a method for producing olefins using the above-described pyrolysis tube 1A for olefin production. Examples of olefins include ethylene and propylene. Examples of hydrocarbon raw materials include ethane and naphtha. The olefin is produced by flowing the hydrocarbon raw material through the pyrolysis tube 1A for olefin production and heating it to 700-9 It is manufactured by heating to 0°C and causing thermal decomposition in the gas phase.

[0049] [Embodiment 2] Other embodiments of the present invention will be described below. For the sake of clarity, components having the same function as those described in the above embodiments will be denoted by the same reference numerals, and their descriptions will not be repeated.

[0050] Figure 3 is a schematic cross-sectional view showing the configuration of the olefin production pyrolysis tube 1B in this embodiment. Figure 4 is an enlarged view of the inner surface of the olefin production pyrolysis tube 1B.

[0051] In the pyrolysis tube 1A for olefin production in Embodiment 1, an alumina film 3, which is a metal oxide film containing Al2O3, is formed on the inner surface of the base material 2 and on the surface of the plate-like body 5, and a dehydrogenation catalyst 4 is supported on the surface of the alumina film 3. In contrast, the pyrolysis tube 1B for olefin production in this embodiment differs from the pyrolysis tube 1A in that, as shown in Figures 3 and 4, the dehydrogenation catalyst 4 is directly supported on the inner surface of the tubular base material 2 made of a heat-resistant metal material and on the surface of the plate-like body 5.

[0052] The pyrolysis tube 1B for olefin production can be manufactured by applying a slurry containing a pre-made dehydrogenation catalyst 4 to the inner surface of the base material 2 and the surface of the plate-like body 5, and then heat-treating it under appropriate conditions such as air or a nitrogen atmosphere to support the dehydrogenation catalyst 4 on the inner surface of the base material 2 and the surface of the plate-like body 5.

[0053] As described above, the pyrolysis tube 1B for olefin production has a dehydrogenation catalyst 4 supported on the inner surface of the base material 2 and on the surface of the plate-like body 5. This allows the dehydrogenation catalyst 4 to act as a dehydrogenation catalyst during pyrolysis using the pyrolysis tube 1B, for example, to produce ethylene from ethane through a dehydrogenation reaction. As a result, the yield of olefins from hydrocarbon raw materials such as ethane and naphtha through pyrolysis can be improved.

[0054] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Examples]

[0055] Below are the dehydrogenation catalysts and ratios of Examples 1 to 8 as examples of the dehydrogenation catalyst of the present invention. The dehydrogenation catalyst of Comparative Example 1, used as a comparative example, will be described first. Examples 1-8 and the comparison The method for preparing the dehydrogenation catalyst in Example 1 is described below.

[0056] (Example 1) The dehydrogenation catalyst in Example 1 was prepared by the citric acid complex polymerization method. Specifically, first, Yttrium nitrate n-hydrate (Y(NO3)3·nH2O) and chromium nitrate (Cr(NO3)3) were weighed in a molar ratio of Y:Cr = 1:1 to prepare the solute. Three times the molar amount of citric acid monohydrate and ethylene glycol relative to the total molar amount of Y and Cr in the solute were dissolved in 1500 times the molar amount of distilled water and thoroughly stirred (hereinafter referred to as the solvent). The solute was mixed with the solvent and heated and stirred at 70°C overnight. After that, it was heated and dried on a pot plate while stirring to obtain a powder. The powder was calcined at 400°C for 2 hours, and then fully calcined at 850°C for 10 hours to prepare YCrO3 as the dehydrogenation catalyst for Example 1.

[0057] (Example 2) The dehydrogenation catalyst of Example 2 was prepared by the citric acid complex polymerization method. Specifically, yttrium nitrate hexahydrate (Y(NO3)3·6H2O), zirconium nitrate dihydrate (ZrO(NO3)2·2H2O), and chromium nitrate (Cr(NO3)3) were weighed in a molar ratio of Y:Zr:Cr = 0.9:0.1:1 to prepare the solute. Three times the molar amount of citric acid monohydrate and ethylene glycol relative to the total molar amount of Y, Zr, and Cr in the solute were dissolved in 1500 times the molar amount of distilled water relative to the total molar amount and thoroughly stirred (hereinafter referred to as the solvent). The solute was mixed with the solvent and heated and stirred overnight at 70°C. After that, it was heated and dried on a pot plate while stirring to obtain a powder. The powder was calcined at 400°C for 2 hours, and then further calcined at 850°C for 10 hours to obtain Y as the dehydrogenation catalyst for Example 2. 0.9 Zr 0.1 CrO3 was prepared.

[0058] (Example 3) Y(NO3)3·6H2O, zirconium oxide nitrate dihydrate (ZrO(NO3)2·2H2O), and chromium nitrate (Cr(NO3)3) were weighed in a molar ratio of Y:Zr:Cr = 0.95:0.05:1 to be used as solutes, in the same manner as in Example 2, and Y(NO3)3 was used as the dehydrogenation catalyst in Example 3. 0.95 Zr0.05 CrO3 was prepared.

[0059] (Example 4) The dehydrogenation catalyst of Example 4 was prepared by the citric acid complex polymerization method. Specifically, yttrium nitrate hexahydrate (Y(NO3)3·6H2O), manganese(III) nitrate hexahydrate (Mn(NO3)3·6H2O), and chromium nitrate nonahydrate (Cr(NO3)3·9H2O) were weighed in a molar ratio of Y:Cr:Mn = 1:0.5:0.5 to prepare the solute. Three times the molar amount of citric acid monohydrate and ethylene glycol relative to the total molar amount of Y, Mn, and Cr in the solute were dissolved in 1500 times the molar amount of distilled water relative to the total molar amount and thoroughly stirred (hereinafter referred to as the solvent). The solute was mixed with the solvent and heated and stirred overnight at 70°C. After that, it was heated and dried on a pot plate while stirring to obtain a powder. The powder was calcined at 400°C for 2 hours, and then further calcined at 850°C for 10 hours, thereby yielding YCr as the dehydrogenation catalyst in Example 4. 0.5 Mn 0.5 O3 was produced.

[0060] (Example 5) The dehydrogenation catalyst in Example 5 was prepared by the citric acid complex polymerization method. Specifically, first, Yttrium nitrate hexahydrate (Y(NO3)3·6H2O) and iron(III) nitrate notahydrate (Fe(NO3)3·9H2O) were weighed in a molar ratio of Y:Fe = 1:1 to prepare the solute. Three times the molar amount of citric acid monohydrate and ethylene glycol relative to the total molar amount of Y and Fe in the solute were dissolved in 1500 times the molar amount of distilled water and thoroughly stirred (hereinafter referred to as the solvent). The solute was mixed with the solvent and heated and stirred at 70°C overnight. After that, it was heated and dried on a pot plate while stirring to obtain a powder. The powder was calcined at 400°C for 2 hours, and then fully calcined at 850°C for 10 hours to prepare YFeO3 as the dehydrogenation catalyst for Example 5.

[0061] (Example 6) The dehydrogenation catalyst of Example 6 was prepared by the citric acid complex polymerization method. Specifically, yttrium nitrate hexahydrate (Y(NO3)3·6H2O) and manganese(III) nitrate hexahydrate (Mn(NO3)3·6H2O) were weighed in a molar ratio of Y:Mn=1:1 to prepare the solute. Three times the molar amount of citric acid monohydrate and ethylene glycol relative to the total molar amount of Y and Mn in the solute were dissolved in 1500 times the molar amount of distilled water and thoroughly stirred (hereinafter referred to as the solvent). The solute was mixed with the solvent and heated and stirred at 70°C overnight. After that, it was heated and dried on a pot plate while stirring to obtain a powder. The powder was calcined at 400°C for 2 hours, and then fully calcined at 850°C for 10 hours to prepare YMnO3 as the dehydrogenation catalyst of Example 6.

[0062] (Example 7) The dehydrogenation catalyst of Example 7 was prepared by the citrate complex polymerization method. Specifically, first, praseodymium(III) nitrate hexahydrate (Pr(NO3)3·6H2O) and chromium nitrate (Cr(NO3)3) were weighed in a molar ratio of Pr:Cr = 1:1 to prepare the solute. Three times the molar amount of citric acid monohydrate and ethylene glycol relative to the total molar amount of Pr and Cr in the solute were dissolved in 1500 times the molar amount of distilled water and thoroughly stirred (hereinafter referred to as the solvent). The solute was mixed with the solvent and heated and stirred at 70°C overnight. After that, it was heated and dried on a pot plate while stirring to obtain a powder. The powder was calcined at 400°C for 2 hours, and then fully calcined at 850°C for 10 hours to prepare PrCrO3 as the dehydrogenation catalyst of Example 7.

[0063] (Example 8) The dehydrogenation catalyst of Example 8 was prepared by the citrate complex polymerization method. Specifically, first, lanthanum(III) nitrate hexahydrate (La(NO3)3·6H2O) and chromium nitrate (Cr(NO3)3) were weighed in a molar ratio of La:Cr = 1:1 to prepare the solute. Three times the molar amount of citrate monohydrate and ethylene glycol relative to the total molar amount of La and Cr in the solute were dissolved in 1500 times the molar amount of distilled water relative to the total molar amount and thoroughly stirred (hereinafter referred to as the solvent). The solute was mixed with the solvent and heated and stirred at 70°C overnight. After that, it was heated and dried on a pot plate while stirring to obtain a powder. The powder was calcined at 400°C for 2 hours, and then fully calcined at 850°C for 10 hours to prepare LaCrO3 as the dehydrogenation catalyst of Example 8.

[0064] (Example 9) The dehydrogenation catalyst of Example 9 was prepared by the citric acid complex polymerization method. Specifically, first, lanthanum(III) nitrate hexahydrate (La(NO3)3·6H2O) and iron(III) nitrate nonahydrate (Fe(NO3)3·9H2O) were weighed in a molar ratio of La:Fe=1:1 to prepare the solute. Three times the molar amount of citric acid monohydrate and ethylene glycol relative to the total molar amount of La and Fe in the solute were dissolved in 1500 times the molar amount of distilled water and thoroughly stirred (hereinafter referred to as the solvent). The solute was mixed with the solvent and heated and stirred at 70°C overnight. After that, it was heated and dried on a pot plate while stirring to obtain a powder. The powder was calcined at 400°C for 2 hours, and then fully calcined at 850°C for 10 hours to prepare LaFeO3 as the dehydrogenation catalyst of Example 9.

[0065] (Example 10) The dehydrogenation catalyst of Example 10 was prepared by the citric acid complex polymerization method. Specifically, first, lanthanum(III) nitrate hexahydrate (La(NO3)3·6H2O) and cobalt(II) nitrate hexahydrate (Co(NO3)2·6H2O) were weighed in a molar ratio of La:Co=1:1 to prepare the solute. Three times the molar amount of citric acid monohydrate and ethylene glycol relative to the total molar amount of La and Co in the solute were dissolved in 1500 times the molar amount of distilled water relative to the total molar amount and thoroughly stirred (hereinafter referred to as the solvent). The solute was mixed with the solvent and heated and stirred at 70°C overnight. After that, it was heated and dried on a pot plate while stirring to obtain a powder. The powder was calcined at 400°C for 2 hours, and then fully calcined at 850°C for 10 hours to prepare LaCoO3 as the dehydrogenation catalyst of Example 10.

[0066] (Example 11) The dehydrogenation catalyst of Example 11 was prepared by the citric acid complex polymerization method. Specifically, first, lanthanum(III) nitrate hexahydrate (La(NO3)3·6H2O) and manganese nitrate hexahydrate (III) (Mn(NO3)3·6H2O) were weighed in a molar ratio of La:Mn=1:1 to prepare the solute. Three times the molar amount of citric acid monohydrate and ethylene glycol relative to the total molar amount of La and Mn in the solute were dissolved in 1500 times the molar amount of distilled water and thoroughly stirred (hereinafter referred to as the solvent). The solute was mixed with the solvent and heated and stirred at 70°C overnight. After that, it was heated and dried on a pot plate while stirring to obtain a powder. The powder was calcined at 400°C for 2 hours, and then fully calcined at 850°C for 10 hours to prepare LaMnO3 as the dehydrogenation catalyst of Example 11.

[0067] (Example 12) The dehydrogenation catalyst of Example 12 was prepared by the citric acid complex polymerization method. Specifically, first, cerium(III) nitrate hexahydrate (Ce(NO3)3·6H2O) and cobalt(II) nitrate hexahydrate (Co(NO3)2·6H2O) were weighed in a molar ratio of Ce:Co=9:1 to prepare the solute. Three times the molar amount of citric acid monohydrate and ethylene glycol relative to the total molar amount of Ce and Co in the solute were dissolved in 1500 times the molar amount of distilled water and thoroughly stirred (hereinafter referred to as the solvent). The solute was mixed with the solvent and heated and stirred at 70°C overnight. After that, it was heated and dried on a pot plate while stirring to obtain a powder. The powder was calcined at 400°C for 2 hours, and then fully calcined at 850°C for 10 hours to obtain the dehydrogenation catalyst of Example 12. 0.9 Co 0.1 O2 was produced.

[0068] (Example 13) The dehydrogenation catalyst of Example 13 was prepared by the citric acid complex polymerization method. Specifically, first, cerium(III) nitrate hexahydrate (Ce(NO3)3·6H2O) and iron(III) nitrate nonahydrate (Fe(NO3)3·9H2O) were weighed in a molar ratio of Ce:Fe=9:1 to prepare the solute. Three times the molar amount of citric acid monohydrate and ethylene glycol relative to the total molar amount of Ce and Fe in the solute were dissolved in 1500 times the molar amount of distilled water and thoroughly stirred (hereinafter referred to as the solvent). The solute was mixed with the solvent and heated and stirred at 70°C overnight. After that, it was heated and dried on a pot plate while stirring to obtain a powder. The powder was calcined at 400°C for 2 hours, and then fully calcined at 850°C for 10 hours to obtain the dehydrogenation catalyst of Example 13. 0.9 Fe 0.1 O2 was produced.

[0069] (Example 14) The dehydrogenation catalyst of Example 14 was prepared by the citric acid complex polymerization method. Specifically, first, cerium(III) nitrate hexahydrate (Ce(NO3)3·6H2O) and chromium nitrate (Cr(NO3)3) were weighed in a molar ratio of Ce:Cr = 9:1 to prepare the solute. Three times the molar amount of citric acid monohydrate and ethylene glycol relative to the total molar amount of Ce and Cr in the solute were dissolved in 1500 times the molar amount of distilled water and thoroughly stirred (hereinafter referred to as the solvent). The solute was mixed with the solvent and heated and stirred at 70°C overnight. After that, it was heated and dried on a pot plate while stirring to obtain a powder. The powder was calcined at 400°C for 2 hours, and then fully calcined at 850°C for 10 hours to obtain the dehydrogenation catalyst of Example 14. 0.9 Cr 0.1 O2 was produced.

[0070] (Example 15) The dehydrogenation catalyst of Example 15 was prepared by the citric acid complex polymerization method. Specifically, yttrium nitrate hexahydrate (Y(NO3)3·6H2O), chromium nitrate nonahydrate (Cr(NO3)3·9H2O), and iron(III) nitrate nonahydrate (Fe(NO3)3·9H2O) were weighed in a molar ratio of Y:Cr:Fe = 1:0.5:0.5 to prepare the solute. Three times the molar amount of citric acid monohydrate and ethylene glycol relative to the total molar amount of Y, Cr, and Fe in the solute were dissolved in 1500 times the molar amount of distilled water relative to the total molar amount and thoroughly stirred (hereinafter referred to as the solvent). The solute was mixed with the solvent and heated and stirred overnight at 70°C. After that, it was heated and dried on a pot plate while stirring to obtain a powder. The powder was calcined at 400°C for 2 hours, and then further calcined at 850°C for 10 hours, thereby obtaining YCr as the dehydrogenation catalyst for Example 15. 0.5 Fe 0.5 O3 was produced.

[0071] (Example 16) The dehydrogenation catalyst of Example 16 was prepared by the citric acid complex polymerization method. Specifically, yttrium nitrate hexahydrate (Y(NO3)3·6H2O), cerium(III) nitrate hexahydrate (Ce(NO3)3·6H2O), and chromium nitrate (Cr(NO3)3) were weighed in a molar ratio of Y:Ce:Cr = 0.9:0.1:1 to prepare the solute. Three times the molar amount of citric acid monohydrate and ethylene glycol relative to the total molar amount of Y, Ce, and Cr in the solute were dissolved in 1500 times the molar amount of distilled water relative to the total molar amount and thoroughly stirred (hereinafter referred to as the solvent). The solute was mixed with the solvent and heated and stirred overnight at 70°C. After that, it was heated and dried on a pot plate while stirring to obtain a powder. The powder was calcined at 400°C for 2 hours, and then further calcined at 850°C for 10 hours to obtain Y as the dehydrogenation catalyst for Example 16. 0.9 Ce 0.1 CrO3 was prepared.

[0072] <Experiment on the thermal decomposition of ethane> Next, we will describe the thermal decomposition experiments of ethane conducted using the dehydrogenation catalysts of Examples 1 to 16. In the thermal decomposition experiments of ethane, first, a mixture of 100 mg of the dehydrogenation catalyst and 392 mg of the inert solid SiC was packed into a quartz tube (inner diameter 4 mm, length 180 mm) to a height of 30 mm. Next, the quartz tube was inserted into a tubular furnace and the temperature inside the tubular furnace was raised to 600°C. Then, a raw material gas adjusted to a volume ratio of ethane (C2H6):water vapor (H2O):nitrogen (N2) = 1.0:1.4:5.6 was supplied to the quartz tube at a flow rate of 118 mL / min to carry out the thermal decomposition reaction of ethane. Of the gas flowing out of the quartz tube, hydrogen (H2) and nitrogen (N2) were analyzed using a TCD gas chromatograph (Shimadzu, GC-8A). Furthermore, ethane (C2H6), ethylene (C2H4), carbon monoxide (CO), and methane (CH4) from the gases effluent from the quartz tube were analyzed using an FID gas chromatograph (Shimadzu, GC-8A) equipped with a metanizer. From these analysis results, the production rate of ethylene (C2H4), the conversion rate of ethane (C3H6), and the selectivity of ethylene (C2H4) were calculated. The yield (%) of ethylene was calculated by multiplying the conversion rate of ethane by the selectivity of ethylene, and the dehydrogenation catalyst activity was evaluated based on the yield of ethylene. Table 1 shows the experimental results of this pyrolysis experiment. Table 1 also shows the results of an experiment conducted without packing the dehydrogenation catalyst as Comparative Example 1.

[0073] [Table 1] As shown in Table 1, when using the dehydrogenation catalysts of Examples 1 to 16, which are embodiments of the present invention... In addition, the yield of ethylene was higher compared to Comparative Example 1. In particular, the yield of ethylene was even higher when using the dehydrogenation catalysts of Examples 1 to 4, which contain Y and Cr. [Explanation of Symbols]

[0074] 1A, 1B Pyrolysis tubes for olefin production 2 Base material 3. Alumina coating (metal oxide coating) 4 Dehydrogenation catalyst 5 Plate-like body

Claims

1. In general formulas, Y １－ｙ Zr ｙ M2O ｘ It is represented as, The aforementioned M2 is at least one element selected from the second group consisting of Cr, Fe, and Mn. The above y is 0 ≤ y ≤ 0.15, A dehydrogenation catalyst in which x is 3.

2. The dehydrogenation catalyst according to claim 1, wherein the M2 comprises at least Cr.

3. The dehydrogenation catalyst according to claim 1, wherein the M2 comprises two elements included in the second group.

4. A pyrolysis tube for olefin production, wherein the dehydrogenation catalyst according to any one of claims 1 to 3 is supported on the inner surface of a tubular base material made of a heat-resistant metal material and / or on the surface of a plate-like body made of a heat-resistant metal material.

5. A method for producing an olefin, comprising producing an olefin using the thermal decomposition tube for olefin production described in claim 4.

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