Catalyst for decomposing organic material, honeycomb structure, method for decomposing organic material, and device for decomposing organic material

Abstract

The present disclosure relates to an organic material decomposition catalyst, and further relates to an organic material decomposition structure coated with the organic material decomposition catalyst, a method for decomposing an organic material using the organic material decomposition catalyst, and an organic material decomposition device provided with the organic material decomposition catalyst. This organic material decomposition catalyst is used for oxygenolysis of an organic material, and contains a ternary composite oxide containing zirconium, manganese, and neodymium, and oxygenolysis of an organic material. According to the present invention, it is possible to provide: a catalyst which exhibits high catalytic activity in terms of initial activity and maintains high catalytic activity even in terms of catalytic activity after poisoning; the present invention relates to a catalyst for decomposing an organic material, which can be regenerated by heating even when poisoned, a honeycomb structure using the catalyst, a method for decomposing an organic material, and an apparatus for decomposing an organic material.

Description

Technical Field

[0001] This disclosure relates to catalysts for the decomposition of organic matter, and further to organic matter decomposition structures, methods for the decomposition of organic matter, and apparatus for the decomposition of organic matter. Background Technology

[0002] The purification of waste gas composed of hydrocarbon-based organic matter typically employs the following method: mixing the waste gas with oxygen-containing gases such as air and heating it, then purifying it through an oxidation combustion reaction that decomposes it into water and carbon dioxide. When using catalyst materials, waste gas purification can be achieved at lower temperatures and higher speeds. Therefore, using catalytic waste gas purification devices can save energy and costs associated with waste gas treatment. Catalyst materials are typically composed of active components such as platinum, palladium, manganese, and cobalt supported on ceramics such as alumina. While platinum and palladium catalysts can treat waste gas at lower temperatures compared to manganese and cobalt-based catalysts, they are more expensive.

[0003] Patent Document 1 proposes a BaZr(Mn)O3 catalyst (BZM-based catalyst) to improve the heat resistance of perovskite-type composite oxide catalysts. Non-Patent Document 1 and Non-Patent Document 2 propose Zr-Mn-based catalysts to suppress degradation in the decomposition of Cl-containing hydrocarbon gases. Furthermore, Patent Document 2 proposes improving the properties of Zr-Mn-based catalysts by performing hydrothermal treatment and high-temperature steam treatment during the manufacturing process.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2015-229137

[0007] Patent Document 2: Chinese Patent No. 111790374 Specification

[0008] Non-patent literature

[0009] Non-Patent Literature 1: Jose I. Gutierrez-Ortiz, 4 others, “Structure of Mn-Zr mixed oxides catalysts and their catalytic performance in the gas-phase oxidation of chlorocarbons”, Chemosphere, 2007, Vol. 68, pp. 1004-1012.

[0010] Non-Patent Literature 2: D. Doebber, 3 others, “MnOx / ZrO2 catalysts for the total oxidation of methane and chloromethane”, Applied Catalysis B: Environmental, 2004, Vol. 52, pp. 135-143. Summary of the Invention

[0011] The problem the invention aims to solve

[0012] As catalysts for waste gas decomposition, catalysts typically use platinum group elements such as platinum, rhodium, and palladium supported on heat-resistant materials like alumina. In catalysts with active components supported on alumina or similar supports, to achieve high catalytic activity, the active components are often made into fine particles and supported on the support. However, this tends to lead to catalyst activity degradation due to the reduction in material surface area. Furthermore, catalysts used for waste gas decomposition are often exposed to high-temperature environments due to the high temperature of the waste gas and the exothermic reaction. Moreover, platinum, rhodium, and palladium are rare resources and therefore expensive, making it difficult to deploy large-scale catalytic waste gas treatment systems due to cost constraints.

[0013] Furthermore, if the catalyst's heat resistance and poisoning resistance are insufficient, its catalytic performance deteriorates rapidly, making catalytic waste gas treatment difficult and increasing the energy cost of such treatment. Therefore, catalysts that can operate stably even at higher temperatures and those that are less prone to degradation by toxic components such as sulfur (S), chlorine (Cl), and phosphorus (P) are needed.

[0014] The BZM catalyst disclosed in Patent Document 1 has improved heat resistance, but its catalytic properties are sometimes reduced due to the reaction with catalyst components when exposed to exhaust gas containing high concentrations of S and / or Cl.

[0015] While the Zr-Mn catalysts disclosed in Non-Patent Literature 1, Non-Patent Literature 2, and Patent Literature 2 exhibit durability against chlorinated hydrocarbons, their heat resistance at higher temperatures remains insufficient. Therefore, when the waste gas treatment temperature reaches high levels, catalyst particles sometimes aggregate, reducing the contact area with the gas and consequently decreasing the waste gas purification performance. Furthermore, as catalyst particles aggregate, the catalyst itself deforms, leading to cracking in granular catalysts and delamination in honeycomb structures coated with the catalyst. This can potentially generate dust, adversely affecting waste gas treatment equipment and downstream processes.

[0016] Thus, the thermal durability of the catalyst, in addition to the operating temperature of the waste gas treatment equipment, also takes into account the possibility of the temperature rise accompanying the combustion of organic matter and the possibility of the operating temperature rising in order to compensate for insufficient treatment capacity, requiring sufficient performance margin.

[0017] The purpose of this disclosure is to provide an organic decomposition catalyst that exhibits high catalytic activity in terms of initial activity, maintains high catalytic activity in terms of post-poisoning catalytic activity, and can be regenerated by heating even under poisoning conditions; a honeycomb structure using the same; a method for decomposing organic matter; and an apparatus for decomposing organic matter.

[0018] Solution for solving the problem

[0019] The disclosed organic decomposition catalyst is an organic decomposition catalyst for oxidative decomposition of organic matter. The organic decomposition catalyst comprises a ternary composite oxide containing zirconium, manganese, and neodymium.

[0020] The effects of the invention

[0021] According to this disclosure, an organic matter decomposition catalyst that exhibits high catalytic activity in terms of initial activity, maintains high catalytic activity in terms of post-poisoning catalytic activity, and can be regenerated by heating even in the case of poisoning, a honeycomb structure using the same, a method for decomposing organic matter, and an apparatus for decomposing organic matter are provided. Attached Figure Description

[0022] Figure 1 This is a schematic diagram illustrating the organic matter decomposition apparatus of this disclosure.

[0023] Figure 2 These are the XRD results of the organic decomposition catalysts in Examples 6, 10, and 19.

[0024] Figure 3 These are TEM (transmission electron microscopy) images and EDX (energy-dispersive X-ray spectroscopy) elemental mapping images of the organic decomposition catalyst of Example 10.

[0025] Figure 4 This is a schematic diagram illustrating the organic matter decomposition device used in the embodiments. Detailed Implementation

[0026] Hereinafter, the organic matter decomposition catalysts of various embodiments of the present disclosure will be described with reference to the accompanying drawings. In the following descriptions of the embodiments, the same or equivalent parts in the drawings will be labeled with the same reference numerals, and their descriptions will not be repeated.

[0027] <Organic matter decomposition catalyst>

[0028] The organic decomposition catalyst disclosed herein is an organic decomposition catalyst for oxidative decomposition of organic matter, comprising a ternary composite oxide (hereinafter also referred to as the first oxide) containing zirconium (Zr), manganese (Mn) and neodymium (Nd). In this specification, a ternary composite oxide refers to an oxide containing three elements other than oxygen, and is a compound with a stable crystal structure.

[0029] The first oxide can be an oxide containing Zr, Mn, and Nd. The presence of the first oxide in the organic decomposition catalyst can be confirmed by X-ray diffraction (XRD) analysis or elemental mapping based on EDX (energy-dispersive X-ray spectroscopy) using TEM (transmission electron microscopy). XRD or TEM-EDX analysis confirms that the crystal structure of the first oxide is a solid solution structure in which Mn and Nd are dispersed within the lattice of zirconium oxide (ZrO2).

[0030] Examples of organic compounds that can be oxidized and decomposed using an organic decomposition catalyst include hydrocarbon gases, sulfur compounds, and nitrogen compounds. The organic compounds can also be volatile organic compounds (VOCs). The organic decomposition catalyst disclosed herein is primarily suitable for the oxidative decomposition of hydrocarbon gases (e.g., aromatic hydrocarbons, alcohols, ketones, aldehydes, carboxylic acids). The organic decomposition catalyst can also be used, for example, for the purification of harmful gases such as waste gases.

[0031] Regarding oxidative decomposition, the combustion reaction of toluene, represented by the following formula (1), will be used as an example for explanation.

[0032] C7H8 + 9O2 → 4H2O + 7CO2 (1)

[0033] By reacting harmful toluene, which has emission restrictions to the atmosphere, with air (oxygen), it is converted into harmless water vapor and carbon dioxide. Since this reaction is exothermic, the reaction site is heated to high temperatures, especially when dealing with high concentrations and / or large quantities of gas. Furthermore, when the organic structure of the hydrocarbons constituting the hydrocarbon series gases contains sulfur and / or chlorine, catalytic performance is reduced due to poisoning caused by the reaction of sulfur and / or chlorine with catalyst components or by strong binding to adsorption sites on the catalyst surface.

[0034] Organic matter decomposition catalysts tend to exhibit improved heat resistance by incorporating a first oxide. This is believed to be because the addition of Mn and Nd to ZrO2 increases the number of active sites, improves the decomposition performance of organic matter, and alters the surface energy of ZrO2, hindering grain growth and improving heat resistance. As a result, the organic matter decomposition catalyst of this disclosure tends to exhibit high initial catalytic activity even when calcined at high temperatures (e.g., 900°C) during its manufacturing process and when used at high temperatures, and also tends to maintain high catalytic activity after poisoning, and even under poisoning conditions, it tends to be easily regenerated by heating. The initial activity, post-poisoning catalytic activity, and post-regeneration catalytic activity were evaluated according to the methods described in the Examples section below.

[0035] Compared to organic decomposition catalysts containing binary composite oxides but without a primary oxide, organic decomposition catalysts containing a primary oxide exhibit higher initial catalytic activity and maintain high catalytic activity even after poisoning. Specifically, compared to organic decomposition catalysts containing, for example, binary composite oxides with Zr and Mn but without a primary oxide, and binary composite oxides with Nd and Zr but without a primary oxide, organic decomposition catalysts containing a primary oxide exhibit higher initial catalytic activity and maintain high catalytic activity even under poisoning conditions. This is believed to be because, by adding both Mn and Nd to ZrO2, compared to binary composite oxides containing either Mn or Nd, Mn and Nd are more easily dispersed in ZrO2. As a result, the number of active sites increases, improving the decomposition performance of organic matter. Furthermore, the surface energy of ZrO2 decreases, hindering grain growth and improving heat resistance.

[0036] Even compared to organic decomposition catalysts containing a mixture of binary composite oxides containing Zr and Mn and binary composite oxides containing Nd and Zr but without a first oxide, the organic decomposition catalyst disclosed herein exhibits high catalytic activity in terms of initial activity and maintains high catalytic activity in terms of post-poisoning catalytic activity.

[0037] In addition to the primary oxide, organic decomposition catalysts may also contain catalytically active oxides (hereinafter referred to as secondary oxides). The secondary oxide may, for example, contain one or more oxides containing manganese or neodymium. The secondary oxide may be, for example, a monolithic oxide or a binary composite oxide; specific examples include Mn3O4, Mn2O3, and Nd2O3. Organic decomposition catalysts may contain only the primary oxide as the catalytically active oxide, or they may contain only both the primary and secondary oxides as the catalytically active oxides.

[0038] The organic decomposition catalyst may consist only of a first oxide, or only of a first oxide and a second oxide. Furthermore, to allow the organic decomposition catalyst to be shaped into granules, honeycomb structures, or easily coated onto a structure, as described later, it may contain a binder and / or an organic solvent. The content of the first oxide in the organic decomposition catalyst, based on the mass of the organic decomposition catalyst, may be, for example, 100% by mass or less, 95% by mass or less, or 90% by mass or less, or 50% by mass or more. It should be noted that in structures coated with the organic decomposition catalyst, such as the honeycomb structure coated with the organic decomposition catalyst described later, the mass of the organic decomposition catalyst refers to the mass of the organic decomposition catalyst coated onto the structure, excluding the mass of the structure (e.g., honeycomb ceramic).

[0039] When the organic matter decomposition catalyst contains a second oxide, the content of the second oxide relative to 100 parts by mass of the first oxide can be, for example, 40 parts by mass or less, preferably 30 parts by mass or less, and for example, more than 0 parts by mass.

[0040] The molar ratio of Mn to Zr in the organic matter decomposition catalyst can be, for example, in the range of 0.02 to 1.00, preferably in the range of 0.05 to 0.70. By making the molar ratio of Mn to Zr in the organic matter decomposition catalyst within the above range, the heat resistance of the organic matter decomposition catalyst is improved. As a result, there is a tendency for it to exhibit high catalytic activity in terms of initial activity, to maintain high catalytic activity after poisoning, and to be easily regenerated by heating even under poisoning conditions.

[0041] The molar ratio of Nd to Zr in the organic matter decomposition catalyst can be, for example, in the range of 0.002 to 0.200, preferably in the range of 0.010 to 0.150. By setting the molar ratio of Nd to Zr in the organic matter decomposition catalyst to the above range, the heat resistance is improved, resulting in a tendency to exhibit high catalytic activity in the initial stage, to maintain high catalytic activity after poisoning, and to be easily regenerated by heating even under poisoning conditions.

[0042] Organic decomposition catalysts can contain a monoclinic ZrO2 crystalline phase (first crystalline phase). The first crystalline phase can be a solid solution in which Mn and Nd are dispersed. Organic decomposition catalysts can contain one or more crystalline phases other than the first crystalline phase (second crystalline phase). The second crystalline phase can include, for example, Mn3O4, Mn2O3, Nd2O3, cubic ZrO2, and tetragonal ZrO2. Organic decomposition catalysts can be identified by XRD analysis.

[0043] The organic matter decomposition catalyst can be configured such that the molar ratio of manganese to zirconium in the organic matter decomposition catalyst is 0.05 or more, the molar ratio of neodymium to zirconium is 0.01 or more, and when the diffraction peak intensity of monoclinic ZrO2 (-111) plane is set as A, the diffraction peak intensity of Nd2O3 (011) plane is set as B, the diffraction peak intensity of Mn3O4 (103) plane is set as C, and the diffraction peak intensity of Mn2O3 (222) plane or NdMnO3 (211) plane is set as D, the ratio of (B+C+D) / A is 0.9 or less. Therefore, high activity can be maintained even after calcination at 900°C (toluene 90% decomposition temperature ≤ 350°C). Furthermore, due to its heat resistance, catalysts whose performance has been reduced due to poisoning can be regenerated by heating. Catalysts containing a certain amount or more of Mn and / or Nd as the main monoclinic ZrO2 exhibit improved catalytic activity. However, in the presence of excessive Mn and / or Nd, heterogeneous phases such as Mn3O4, Mn2O3, NdMnO3, and Nd2O3 increase, as confirmed by XRD measurements. It is believed that the Mn and / or Nd constituting these heterogeneous phases do not disperse on ZrO2 but instead undergo grain growth at high temperatures, thus reducing catalytic activity. To effectively suppress the decrease in activity, the ratio of the total XRD peak intensity of the aforementioned heterogeneous phases (Mn3O4, Mn2O3, NdMnO3, Nd2O3) to the XRD peak intensity of the main phase (monoclinic ZrO2) (hereinafter also referred to as the heterogeneous phase / main phase peak ratio) should be 0.9 or less. A, B, C, and D above were determined according to the methods described in the Examples section below.

[0044] Organic matter decomposition catalysts can be prepared, for example, as follows: First, pebbles, water, and an organic binder are added to ZrO2, Mn3O4, and Nd2O3 and mixed to obtain a mixture. Mixing can be performed using a ball mill or similar device. Next, the mixture is dried in an oven at 120°C, pulverized, and classified to produce particles with a particle size of several hundred μm to several mm. Then, the resulting granular sample is calcined in air at 900°C for 2 hours. This yields the organic matter decomposition catalyst.

[0045] The temperature at which the organic matter decomposition catalyst can exert its catalytic activity in terms of initial activity can be, for example, above 300°C and below 510°C, preferably above 310°C and below 460°C.

[0046] The temperature at which the organic matter decomposition catalyst can exert its catalytic activity after poisoning can be, for example, above 400°C and below 700°C, preferably above 420°C and below 620°C, and more preferably above 420°C and below 540°C.

[0047] The temperature at which the organic matter decomposition catalyst can exert its catalytic activity after regeneration by heating can be, for example, above 300°C and below 700°C, preferably above 340°C and below 540°C, and more preferably above 340°C and below 470°C.

[0048] This organic decomposition catalyst offers improved heat resistance, exhibits high initial catalytic activity, maintains high catalytic activity even after poisoning, and can be regenerated by heating even under poisoning conditions. Therefore, it is suitable for decomposing volatile organic compounds (VOCs) generated and contributing to environmental pollution in processes such as painting, molding, combustion, and waste treatment in living environments and industrial sectors. Additionally, it can also be used for applications such as the purification of automotive exhaust.

[0049] <Formats of Catalysts for Organic Matter Decomposition>

[0050] Organic matter decomposition catalysts can be used, for example, in the form of granular catalysts processed into particles of several millimeters to several centimeters in size, and in the form of honeycomb catalysts processed into a honeycomb shape. Alternatively, by coating the surface of a honeycomb ceramic with the organic matter decomposition catalyst, it can also be used as a honeycomb structure coated with the organic matter decomposition catalyst. By adopting a honeycomb structure, pressure loss during gas flow can be reduced. Furthermore, by increasing the density of the honeycomb cells, the effective surface area increases, thus easily improving the decomposition rate of organic matter.

[0051] Methods for decomposing organic matter

[0052] Another embodiment of this disclosure relates to a method for decomposing organic matter, which includes a decomposition step of oxidizing and decomposing organic matter by heating using the aforementioned organic matter decomposition catalyst. In the decomposition step, the organic matter can be decomposed by heating while contacting it with the organic matter decomposition catalyst. The above description of organic matter applies to organic matter. The method for decomposing organic matter can be performed using the organic matter decomposition apparatus described later.

[0053] The heating temperature in the decomposition process can be, for example, 300°C or higher and 900°C or lower. If the heating temperature in the decomposition process is within the above range, the catalytic activity of the organic matter decomposition catalyst can be exerted, even after poisoning. From the perspective of suppressing catalyst performance degradation and energy costs, the heating temperature in the decomposition process is preferably 300°C or higher and 700°C or lower, more preferably 300°C or higher and 600°C or lower, and even more preferably 300°C or higher and 540°C or lower.

[0054] As a method of heating while simultaneously contacting the organic matter with the organic matter decomposition catalyst, one approach is to fill a tube with the organic matter decomposition catalyst, introduce the organic matter into the tube, and heat the portion of the tube in contact with the organic matter from the outside. The organic matter decomposition catalyst filled in the tube can be the granular catalyst, honeycomb catalyst, or a honeycomb structure coated with the organic matter decomposition catalyst described above. Alternatively, it can be an aggregate of the organic matter decomposition catalyst.

[0055] The method for decomposing organic matter may further include a regeneration step, which restores catalytic activity by heating the organic matter decomposition catalyst used in the decomposition step to a temperature above the heating temperature in the decomposition step. The regeneration step can be carried out by heating the organic matter decomposition catalyst used in the decomposition step at a temperature above the heating temperature in the decomposition step while contacting the catalyst with air. The organic matter decomposition catalyst used in the decomposition step may be poisoned by S, Cl, P, etc.

[0056] The temperature above the heating temperature in the above decomposition process can be, for example, 300°C or higher and 900°C or lower. From the viewpoint of the catalytic activity of the regenerated catalyst and energy cost, it is preferably 400°C or higher and 800°C or lower, more preferably 600°C or higher and 800°C or lower.

[0057] A method for heating the organic decomposition catalyst used in the decomposition process while it is in contact with air can be, for example, by introducing air into a tube filled with the organic decomposition catalyst used in the decomposition process and heating it from the outside of the tube.

[0058] <Organic matter decomposition device>

[0059] Another embodiment of the organic matter decomposition apparatus disclosed herein includes: a tube through which organic matter flows; and a heating unit for heating the organic matter flowing in the tube. The aforementioned organic matter decomposition catalyst is disposed inside the tube in a region heated by the heating unit.

[0060] Reference Figure 1 The organic matter decomposition device is described. Figure 1The organic matter decomposition device 10 shown includes: a pipe 1 for supplying organic matter; a heating unit 2 for heating the organic matter flowing in the pipe 1; and a control unit 3 for controlling the heating unit 2.

[0061] An organic decomposition catalyst 6 is disposed in the area heated by the heating unit 2 inside the tube 1. The organic decomposition catalyst 6 can be any of the above-mentioned organic decomposition catalysts, and its form can be an aggregate, the above-mentioned granular catalyst, a honeycomb catalyst, or a honeycomb structure coated with an organic decomposition catalyst.

[0062] Pipe 1 has a gas inlet 4 on its upstream side. A gas supply pipe 7 is connected to the gas inlet 4. On the upstream side of pipe 1, an organic matter supply line 41 for supplying organic matter (e.g., toluene), a nitrogen supply line 42 for supplying nitrogen (N2), and an oxygen supply line 43 for supplying oxygen (O2) are connected to the gas supply pipe 7. That is, a gas containing organic matter, nitrogen, and oxygen is supplied to pipe 1 via the gas supply pipe 7.

[0063] Tube 1 has a reaction gas outlet 5 on its downstream side. A gas discharge pipe 8 is connected to the reaction gas outlet 5, which is used to discharge the treated gas after the organic matter in tube 1 has been decomposed to the outside of the system. A sampling line 51 for sampling the treated gas is connected to the gas discharge pipe 8, which is configured to enable the analysis of the concentration of organic matter in the treated gas by gas chromatography.

[0064] The control unit 3 is configured to control the temperature of the area heated by the heating unit 2 to, for example, 300°C or higher and 900°C or lower.

[0065] Furthermore, the control unit 3 is configured to control the heating unit 2 to maintain the temperature of the organic matter decomposition catalyst 6 at 300°C or higher and 900°C or lower. By controlling the temperature of the organic matter decomposition catalyst 6 to 300°C or higher and 900°C or lower, the catalytic activity of the organic matter decomposition catalyst 6 can be further improved. In addition, by controlling the temperature of the organic matter decomposition catalyst 6 to 900°C or lower, the deterioration of the organic matter decomposition catalyst 6 can be suppressed.

[0066] Furthermore, the organic matter decomposition catalyst 6, after the organic matter has been decomposed, can undergo a regeneration process as follows: while supplying oxygen and nitrogen to pipe 1 without supplying organic matter, it is heated by heating unit 2 while the temperature of the organic matter decomposition catalyst 6 is controlled by control unit 3 to be above the heating temperature in the decomposition process, thereby restoring the catalytic activity of the organic matter decomposition catalyst 6. The regeneration process aims to remove toxic components from the catalyst through heating, therefore it needs to be heated to a temperature above the operating temperature, but it can also be carried out while organic matter is being supplied.

[0067] Example

[0068] The present disclosure will now be described in more detail through examples. Unless otherwise specified, “%” and “parts” in the examples refer to mass percentage and mass parts, respectively. It should be noted that the organic decomposition catalysts of the various examples and comparative examples shown below were analyzed using a fluorescence X-ray analysis device, confirming the composition of the organic decomposition catalysts as described in Tables 1 and 2.

[0069] <Example 1>

[0070] As raw materials for the organic matter decomposition catalyst, ZrO2, Mn3O4, and Nd2O3 were weighed in a Zr:Mn:Nd molar ratio of 1.00:0.10:0.002. Pebbles, water, and an organic binder were added and mixed. The resulting mixture was dried in an oven at 120°C, then pulverized and graded to produce granules of 0.5–0.7 mm. The resulting granular samples were calcined in air at 900°C for 2 hours to obtain the organic matter decomposition catalyst of Example 1.

[0071] <Example 2>

[0072] As raw materials for the organic matter decomposition catalyst, ZrO2, Mn3O4 and Nd2O3 were weighed in a Zr:Mn:Nd molar ratio of 1.00:0.10:0.005. Otherwise, the organic matter decomposition catalyst of Example 2 was obtained in the same manner as in Example 1.

[0073] <Example 3>

[0074] As raw materials for the organic matter decomposition catalyst, ZrO2, Mn3O4 and Nd2O3 were weighed in a Zr:Mn:Nd molar ratio of 1.00:0.10:0.010. Otherwise, the organic matter decomposition catalyst of Example 3 was obtained in the same manner as in Example 1.

[0075] <Example 4>

[0076] As raw materials for the organic matter decomposition catalyst, ZrO2, Mn3O4 and Nd2O3 were weighed in a Zr:Mn:Nd molar ratio of 1.00:0.10:0.020. Otherwise, the organic matter decomposition catalyst of Example 4 was obtained in the same manner as in Example 1.

[0077] <Example 5>

[0078] As raw materials for the organic matter decomposition catalyst, ZrO2, Mn3O4 and Nd2O3 were weighed in a Zr:Mn:Nd molar ratio of 1.00:0.10:0.050. Otherwise, the organic matter decomposition catalyst of Example 5 was obtained in the same manner as in Example 1.

[0079] <Example 6>

[0080] As raw materials for the organic matter decomposition catalyst, ZrO2, Mn3O4 and Nd2O3 were weighed in a Zr:Mn:Nd molar ratio of 1.00:0.10:0.100. Otherwise, the organic matter decomposition catalyst of Example 6 was obtained in the same manner as in Example 1.

[0081] <Example 7>

[0082] As raw materials for the organic matter decomposition catalyst, ZrO2, Mn3O4 and Nd2O3 were weighed in a Zr:Mn:Nd molar ratio of 1.00:0.10:0.150. Otherwise, the organic matter decomposition catalyst of Example 7 was obtained in the same manner as in Example 1.

[0083] <Example 8>

[0084] As raw materials for the organic matter decomposition catalyst, ZrO2, Mn3O4 and Nd2O3 were weighed in a Zr:Mn:Nd molar ratio of 1.00:0.10:0.200. Otherwise, the organic matter decomposition catalyst of Example 8 was obtained in the same manner as in Example 1.

[0085] <Example 9>

[0086] As raw materials for the organic matter decomposition catalyst, ZrO2, Mn3O4 and Nd2O3 were weighed in a Zr:Mn:Nd molar ratio of 1.00:0.01:0.100. Otherwise, the organic matter decomposition catalyst of Example 9 was obtained in the same manner as in Example 1.

[0087] <Example 10>

[0088] As raw materials for the organic matter decomposition catalyst, ZrO2, Mn3O4 and Nd2O3 were weighed in a Zr:Mn:Nd molar ratio of 1.00:0.05:0.100. Otherwise, the organic matter decomposition catalyst of Example 10 was obtained in the same manner as in Example 1.

[0089] <Example 11>

[0090] As raw materials for the organic matter decomposition catalyst, ZrO2, Mn3O4 and Nd2O3 were weighed in a Zr:Mn:Nd molar ratio of 1.00:0.15:0.100. Otherwise, the organic matter decomposition catalyst of Example 11 was obtained in the same manner as in Example 1.

[0091] <Example 12>

[0092] As raw materials for the organic matter decomposition catalyst, ZrO2, Mn3O4 and Nd2O3 were weighed in a Zr:Mn:Nd molar ratio of 1.00:0.20:0.100. Otherwise, the organic matter decomposition catalyst of Example 12 was obtained in the same manner as in Example 1.

[0093] <Example 13>

[0094] As raw materials for the organic matter decomposition catalyst, ZrO2, Mn3O4 and Nd2O3 were weighed in a Zr:Mn:Nd molar ratio of 1.00:0.40:0.100. Otherwise, the organic matter decomposition catalyst of Example 13 was obtained in the same manner as in Example 1.

[0095] <Example 14>

[0096] As raw materials for the organic matter decomposition catalyst, ZrO2, Mn3O4 and Nd2O3 were weighed in a Zr:Mn:Nd molar ratio of 1.00:0.70:0.100. Otherwise, the organic matter decomposition catalyst of Example 14 was obtained in the same manner as in Example 1.

[0097] <Example 15>

[0098] As raw materials for the organic matter decomposition catalyst, ZrO2, Mn3O4 and Nd2O3 were weighed in a Zr:Mn:Nd molar ratio of 1.00:1.00:0.100. Otherwise, the organic matter decomposition catalyst of Example 15 was obtained in the same manner as in Example 1.

[0099] <Example 16>

[0100] As raw materials for the organic matter decomposition catalyst, ZrO2, Mn3O4 and Nd2O3 were weighed in a Zr:Mn:Nd molar ratio of 1.00:0.02:0.002. Otherwise, the organic matter decomposition catalyst of Example 16 was obtained in the same manner as in Example 1.

[0101] <Example 17>

[0102] As raw materials for the organic matter decomposition catalyst, ZrO2, Mn3O4 and Nd2O3 were weighed in a Zr:Mn:Nd molar ratio of 1.00:0.02:0.150. Otherwise, the organic matter decomposition catalyst of Example 17 was obtained in the same manner as in Example 1.

[0103] <Example 18>

[0104] As raw materials for the organic matter decomposition catalyst, ZrO2, Mn3O4 and Nd2O3 were weighed in a Zr:Mn:Nd molar ratio of 1.00:0.40:0.002. Otherwise, the organic matter decomposition catalyst of Example 18 was obtained in the same manner as in Example 1.

[0105] <Example 19>

[0106] As raw materials for the organic matter decomposition catalyst, ZrO2, Mn3O4 and Nd2O3 were weighed in a Zr:Mn:Nd molar ratio of 1.00:0.40:0.150. Otherwise, the organic matter decomposition catalyst of Example 19 was obtained in the same manner as in Example 1.

[0107] <Example 20>

[0108] As raw materials for the organic matter decomposition catalyst, ZrO2, Mn3O4 and Nd2O3 were weighed in a Zr:Mn:Nd molar ratio of 1.00:0.10:0.250. Otherwise, the mixing and calcination were carried out in the same manner as in Example 1, thereby obtaining the organic matter decomposition catalyst of Example 20.

[0109] <Comparative Example 1>

[0110] As raw materials for the organic matter decomposition catalyst, BaCO3, ZrO2, and Mn3O4 were weighed in a Ba:Zr:Mn molar ratio of 1.00:0.90:0.10. Pebbles, water, and an organic binder were added and mixed. The resulting mixture was dried in an oven at 120°C, then pulverized and graded to produce granules of 0.5–0.7 mm. The resulting granular samples were calcined in air at 1000°C for 2 hours to obtain the organic matter decomposition catalyst of Comparative Example 1.

[0111] <Comparative Example 2>

[0112] ZrO2 and Mn3O4 were used as raw materials for the organic matter decomposition catalyst and weighed in a Zr:Mn molar ratio of 1.00:0.02. Otherwise, the mixing and calcination were carried out in the same manner as in Example 1, thereby obtaining the organic matter decomposition catalyst of Comparative Example 2.

[0113] <Comparative Example 3>

[0114] ZrO2 and Nd2O3 were used as raw materials for the organic matter decomposition catalyst and weighed in a Zr:Nd molar ratio of 1.00:0.10. Otherwise, the mixing and calcination were carried out in the same manner as in Example 1, thereby obtaining the organic matter decomposition catalyst of Comparative Example 3.

[0115] [Identification of Crystal Phase]

[0116] The organic decomposition catalysts of the examples and comparative examples were pulverized in a mortar, and the crystal phases were confirmed by powder XRD (X-ray source: Cu-Kα1). The types of crystal phases detected by the organic decomposition catalysts of the examples and comparative examples are shown in Table 1.

[0117] [Determination of heterogeneous / main phase peak ratio]

[0118] To quantify the contents of the heterogeneous components (Mn3O4, Mn2O3, NdMnO3, and Nd2O3) confirmed by powder XRD measurements relative to the monoclinic ZrO2, the main phase of this catalyst, the ratio of the sum of diffraction peak intensities of the heterogeneous components to the diffraction peak intensities of the main phase, i.e., the heterogeneous / main phase peak ratio, was calculated and the results are shown in Table 1. Here, the maximum values ​​of the diffraction peak intensities from the following crystal planes are used as the diffraction peak intensities for each crystal phase.

[0119] A: Diffraction peak intensity of monoclinic ZrO2 in the (-111) plane at 2θ = 27.5~28.8 degrees.

[0120] B: Diffraction peak intensity of Nd₂O₃ on the (10₃) plane at 2θ = 30.6~31.0 degrees

[0121] C: Diffraction peak intensity of Mn3O4(103) plane existing at 2θ = 32.1~32.5 degrees

[0122] D: The diffraction peak intensity of Mn2O3 on the (222) plane or NdMnO3 on the (211) plane, existing at 2θ = 32.6~33.2 degrees.

[0123] It should be noted that the strongest lines of Mn2O3 and NdMnO3 appear in the same angular region. Therefore, the maximum intensity of the diffraction peak existing at 2θ = 32.6~33.2 degrees is taken as the peak intensity of Mn2O3 and NdMnO3.

[0124] [Table 1]

[0125]

[0126] As shown in Table 1, the catalysts of Examples 1-20 confirmed the presence of a monoclinic ZrO2 crystal phase (denoted as m-ZrO2 in Table 1), and corresponding to the composition ratios, Mn3O4, Mn2O3, Nd2O3, cubic, or tetragonal ZrO2 crystal phases (denoted as c-ZrO2 in Table 1). Furthermore, the catalyst of Comparative Example 1 confirmed the presence of a perovskite structure crystal phase.

[0127] The XRD measurement results of Examples 6, 10, and 19 are shown below. Figure 2 The catalyst of Example 6, composed of Zr-Mn-Nd, showed m-ZrO2, Mn2O3, and NdMnO3, but not Nd2O3 or Mn3O4. Therefore, it is believed that by simultaneously adding Mn and Nd to ZrO2, Nd and Mn entered the monoclinic ZrO2 crystal phase and were highly dispersed. Furthermore, in the catalyst of Example 10, not only were Nd2O3 and Mn3O4 not detected, but Mn2O3 and NdMnO3 were also not detected. Therefore, it is believed that Nd and Mn entered the monoclinic ZrO2 crystal phase and were highly dispersed. It should be noted that in the catalyst of Example 19, where excess Mn and Nd were added, c-ZrO2 and Mn3O4 crystal phases were also detected. It is believed that the addition of excess Mn and Nd generated a ZrO2 structure other than monoclinic and undispersed Mn and Nd.

[0128] Figure 3 The image shows a TEM (transmission electron microscope) image of Example 10 and an elemental mapping image of Zr, Mn, and Nd based on EDX (energy-dispersive X-ray spectroscopy) of the same field of view. The distribution of Zr, Mn, and Nd elements in the catalyst particles of Example 10 is consistent, and it is considered to be a solid solution crystal structure formed by Mn and Nd dispersedly entering the lattice of zirconium oxide (ZrO2).

[0129] [Initial activity evaluation of the catalyst]

[0130] The combustion reaction of toluene was carried out using the catalysts of the examples and comparative examples. Figure 4 The organic decomposition apparatus 100 shown is filled with 0.1 cc of organic decomposition catalyst 103 in reaction tube 101 and heated to a specified temperature using heater 102. Air containing 1000 ppm of toluene is introduced from gas inlet 104 at a flow rate of 580 cc / min. In the experiment, the gas after the reaction is collected from reaction gas outlet 105, and the toluene concentration [ppm] at the outlet is determined using a gas chromatograph. The decomposition rate of toluene is confirmed according to the following formula.

[0131] Toluene decomposition rate [%] = (1000 - outlet toluene concentration) / 1000

[0132] Regarding the test temperature, the test was conducted by increasing the temperature in 10°C increments starting from 200°C, and the temperature at which the toluene decomposition rate reached 90% was defined as the "90% decomposition temperature of toluene". The results are shown in Table 2.

[0133] [Evaluation of catalytic activity after SO2 poisoning]

[0134] The catalysts of the examples and comparative examples were subjected to SO2-based poisoning treatment. Figure 4 The organic decomposition apparatus 100 shown is filled with 0.1 cc of organic decomposition catalyst 103 in reaction tube 101, heated to 600°C using heater 102, and then air containing 50 ppm SO2 is introduced through gas inlet 104 at a flow rate of 580 cc / min. After maintaining this temperature for 2 hours, the temperature is lowered. Then, using the same method as in the "Initial Activity Evaluation of Catalyst," the "90% Decomposition Temperature of Toluene" is determined for the SO2-poisoned catalyst. The results are shown in Table 2.

[0135] [Evaluation of catalytic activity after heating and regeneration]

[0136] Regarding the catalysts of the examples and comparative examples, after being poisoned using the same method as in "Evaluation of Catalytic Activity After SO2 Poisoning", ... Figure 4 The organic decomposition apparatus 100 shown has tube 1 filled with 0.1 cc of organic decomposition catalyst 103, heated to 800°C using heater 102, and air introduced through gas inlet 104 at a flow rate of 580 cc / min. This temperature is maintained for 0.5 h before cooling. Then, using the same method as in the "Initial Activity Evaluation of Catalyst," the "90% Decomposition Temperature of Toluene" is determined for the regenerated catalyst. The results are shown in Table 2.

[0137] <Example 21>

[0138] In Example 5, pebbles, water, and an organic binder were added and pulverized to prepare a catalyst slurry. Cordierite honeycomb (200 cpsi) was immersed in the obtained catalyst slurry for one minute, followed by air blowing to coat the catalyst. Then, after drying in an oven at 120°C, it was calcined at 800°C for 2 hours to obtain the honeycomb-coated catalyst of Example 21. Furthermore, the catalyst coating weight per unit volume of honeycomb was 100 g / L.

[0139] [Characteristic Evaluation of Cellular Coated Catalysts]

[0140] A 14-cell × 50 mm long honeycomb catalyst for activity evaluation was cut from the honeycomb coated catalyst of Example 21. The honeycomb coated catalyst of Example 21 was designated as organic matter decomposition catalyst 103. Except for this, the [initial activity evaluation of the catalyst], [catalytic activity evaluation after SO2 poisoning], and [catalytic activity evaluation after heat regeneration] were performed under the same conditions as in Example 5. The results are shown in Table 2.

[0141] [Table 2]

[0142]

[0143] The organic decomposition catalysts of Examples 1-20 exhibited high catalytic activity in terms of initial activity and maintained high catalytic activity after poisoning. Furthermore, they could be regenerated by heating even under poisoning conditions. On the other hand, the organic decomposition catalyst of Comparative Example 1 showed a significant decrease in decomposition performance due to SO2 poisoning; even at 700°C, the toluene decomposition rate did not reach 90%. Moreover, the organic decomposition catalyst of Comparative Example 1 did not recover its catalytic activity even after heating regeneration at 800°C. Furthermore, in Comparative Examples 2 and 3, high catalytic activity was not achieved in terms of initial activity, post-poisoning activity, or activity after heating regeneration.

[0144] For the honeycomb-coated catalyst of Example 21, poisoning occurs on the coating surface directly in contact with the flowing gas. Therefore, compared with the granular catalyst (Example 5), there is a tendency for reduced activity after poisoning, but the initial activity and recovery based on regeneration treatment show the same characteristics. In addition, the pressure loss during gas flow reaction can be reduced in the honeycomb catalyst. The pressure loss during catalytic activity evaluation of the granular catalyst (Example 5) increased to 6 kPa, while the honeycomb-coated catalyst (Example 21) can maintain a pressure loss of less than 1 kPa.

[0145] In the above description of the embodiments, the components that can be combined can also be combined with each other.

[0146] The embodiments disclosed herein should be considered illustrative rather than restrictive in all respects. The scope of this disclosure is defined not by the foregoing description but by the claims, and is intended to include all modifications equivalent to and within the scope of the claims.

[0147] Those skilled in the art will understand that the above-described exemplary embodiments are specific examples of the following approaches.

[0148] (First item) An organic decomposition catalyst is an organic decomposition catalyst used for the oxidative decomposition of organic matter. The organic decomposition catalyst comprises a ternary composite oxide containing zirconium, manganese, and neodymium.

[0149] (Second item) In the organic matter decomposition catalyst described in the first item, the molar ratio of manganese to zirconium in the organic matter decomposition catalyst is in the range of 0.02 to 1.00.

[0150] (Third item) In the organic matter decomposition catalyst described in the first item, the molar ratio of manganese to zirconium in the organic matter decomposition catalyst is in the range of 0.05 to 0.70.

[0151] (Fourth item) In any one of the organic decomposition catalysts in the first to third items, the molar ratio of neodymium to zirconium in the organic decomposition catalyst is in the range of 0.002 to 0.200.

[0152] (Fifth item) In any one of the organic matter decomposition catalysts in the first to third items, the molar ratio of neodymium to zirconium in the organic matter decomposition catalyst is in the range of 0.010 to 0.150.

[0153] (Sixth item) Any one of the organic decomposition catalysts in items one through five comprises a monoclinic zirconium oxide phase.

[0154] (Seventh item) In any one of the organic decomposition catalysts in items one to six, the molar ratio of manganese to zirconium in the organic decomposition catalyst is 0.05 or more, the molar ratio of neodymium to zirconium is 0.01 or more, and when the intensity of the (-111) diffraction peak of monoclinic ZrO2 in XRD is set as A, the intensity of the (011) diffraction peak of Nd2O3 is set as B, the intensity of the (103) diffraction peak of Mn3O4 is set as C, and the intensity of the (222) diffraction peak of Mn2O3 or the (211) diffraction peak of NdMnO3 is set as D, (B+C+D) / A is 0.9 or less.

[0155] (Eighth item) A honeycomb structure coated with an organic decomposition catalyst as described in any one of the first to seventh items.

[0156] (Ninth item) A method for decomposing organic matter, comprising a decomposition step, wherein the decomposition step is performed by heating with an organic matter decomposition catalyst as described in any one of the first to seventh items, thereby oxidizing and decomposing the organic matter.

[0157] (Item 10) The method for decomposing organic matter according to Item 9 further includes a regeneration step, wherein the regeneration step restores catalytic activity by heating the organic matter decomposition catalyst used in the decomposition step to a temperature above the heating temperature in the decomposition step.

[0158] (11) An organic matter decomposition apparatus comprising: a tube for supplying organic matter; and a heating section for heating the organic matter flowing in the tube, wherein an organic matter decomposition catalyst as described in any one of the first to seventh claims is disposed in a region inside the tube heated by the heating section.

[0159] Explanation of reference numerals in the attached figures

[0160] 1. Tube; 2. Heating section; 3. Control section; 4. Gas inlet; 5. Reaction gas outlet; 6. Organic decomposition catalyst; 7. Gas supply pipe; 8. Gas exhaust pipe; 10. Organic decomposition device; 41. Organic supply line; 42. Nitrogen supply line; 43. Oxygen supply line; 51. Sampling line; 101. Reaction tube; 102. Heater.

Claims

1. An organic matter decomposition catalyst, which is used for the oxidative decomposition of organic matter. It contains ternary composite oxides containing zirconium, manganese and neodymium.

2. The organic matter decomposition catalyst according to claim 1, wherein, The molar ratio of manganese to zirconium in the organic matter decomposition catalyst is in the range of 0.02 to 1.

00.

3. The organic matter decomposition catalyst according to claim 1, wherein, The molar ratio of manganese to zirconium in the organic matter decomposition catalyst is in the range of 0.05 to 0.

70.

4. The organic matter decomposition catalyst according to any one of claims 1 to 3, wherein, The molar ratio of neodymium to zirconium in the organic matter decomposition catalyst is in the range of 0.002 to 0.

200.

5. The organic matter decomposition catalyst according to any one of claims 1 to 3, wherein, The molar ratio of neodymium to zirconium in the organic matter decomposition catalyst is in the range of 0.010 to 0.

150.

6. The organic decomposition catalyst according to any one of claims 1 to 5, comprising a monoclinic zirconium oxide phase.

7. The organic matter decomposition catalyst according to any one of claims 1 to 6, wherein, In the organic matter decomposition catalyst, the molar ratio of manganese to zirconium is greater than 0.05, and the molar ratio of neodymium to zirconium is greater than 0.

01. Let A be the intensity of the (-111) plane diffraction peak of monoclinic ZrO2 in XRD. Let the intensity of the (011) plane diffraction peak of Nd2O3 be set as B. The intensity of the (103) plane diffraction peak of Mn3O4 is set to C, and When the intensity of the (222) diffraction peak of Mn2O3 or (211) plane of NdMnO3 is set to D, (B+C+D) / A is less than 0.

9.

8. A honeycomb structure coated with an organic decomposition catalyst according to any one of claims 1 to 7.

9. A method for decomposing organic matter, comprising a decomposition step, wherein the decomposition step involves heating the organic matter using an organic matter decomposition catalyst according to any one of claims 1 to 7, thereby oxidizing and decomposing the organic matter.

10. The method for decomposing organic matter according to claim 9, further comprising a regeneration step, wherein the regeneration step restores catalytic activity by heating the organic matter decomposition catalyst used in the decomposition step to a temperature above the heating temperature in the decomposition step.

11. An organic matter decomposition device, comprising: Pipes, which supply the circulation of organic matter; and, The heating section heats the organic matter flowing in the pipe. An organic decomposition catalyst according to any one of claims 1 to 7 is disposed in the area inside the tube that is heated by the heating unit.

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