Synthesis method of propane oxidative dehydrogenation catalyst and application thereof

Abstract

The application relates to a synthesis method of a propane oxidative dehydrogenation catalyst and application thereof, and comprises the following steps: preparing a zirconium-based gel powder; mixing a chromium solution with the zirconium-based gel powder to load an active substance; coating and growing a metal or metal oxide on a micro-mesoporous material to obtain a modified metal oxide material; mixing the active substance, the modified metal oxide material and an inert carrier to form a shape, and then drying, roasting and reducing to obtain the propane oxidative dehydrogenation catalyst. The application adopts a precipitation method to respectively prepare an active carrier and a catalytic active substance, and then mixes the active substance, the modified metal oxide and the inert carrier to form a shape, and then dries and roasts to prepare a shaped catalyst, so that the catalytic performance of the active substance can be fully exerted. The catalytic active component is a chromium-loaded powder, which is used for converting propane; the inert carrier increases the strength and thermal stability of the catalyst; and the modified metal oxide can react with generated hydrogen in the reaction process, promotes the forward movement of the reaction equilibrium, and plays an active additive role.

Description

Technical Field

[0001] The present application relates to a method for synthesizing a propane oxidative dehydrogenation catalyst and its application. Background Art

[0002] Propylene is an important basic organic chemical raw material. In addition to producing polypropylene, it can also be made into numerous downstream products, including acrolein, polyacrylonitrile, propylene oxide, acrylic acid, glycerol, isopropyl alcohol, and 1,2-octanol. Currently, propylene is produced from steam cracking, catalytic cracking, methanol-to-olefins (MTO), and propane dehydrogenation. Steam cracking can produce both propylene and ethylene, but their ratios are limited. Catalytic cracking primarily produces various refined products, with propylene as a component of the liquefied petroleum gas product, resulting in a relatively low upper yield limit. Among specialized propylene production processes, the MTO methanol-to-olefins process uses coal-based methanol as a feedstock and produces propylene and ethylene, with their ratios also limited. In contrast, propane dehydrogenation (PDH) technology uses propane as a feedstock and offers advantages such as mature technology, high product quality, high conversion rates, and low by-product counts. With the increasing development and utilization of shale gas resources, propane dehydrogenation offers a competitive propylene production process, with its production capacity accounting for a growing proportion of overall propylene production.

[0003] Propane dehydrogenation can be divided into two basic processes: direct dehydrogenation and oxidative dehydrogenation. Direct propane dehydrogenation is currently the mainstream process in industry, primarily based on chromium oxide- and platinum-based catalysts. However, because direct propane dehydrogenation is an endothermic, reversible reaction, its single-pass conversion rate is limited by heating capacity and reaction temperature. Therefore, oxidative dehydrogenation of propane, as an alternative process, can oxidize the hydrogen byproduct generated during the dehydrogenation process to supplement the heat required for the reaction, and can also improve the single-pass conversion rate by reducing the hydrogen partial pressure. There are many ways to introduce oxygen into propane oxidative dehydrogenation, such as using pure oxygen, oxygen-containing compounds such as CO2, or metal oxides that can react with H2 as oxygen carriers. The process using oxygen or oxygen-containing compounds has low reaction selectivity due to the generation of COx, and CO in the generated product is difficult to separate. The method using an oxygen carrier allows the dehydrogenation active center to complete the dehydrogenation reaction, and the oxygen carrier reacts with the generated hydrogen to generate water, consuming hydrogen and driving the dehydrogenation reaction equilibrium, thereby achieving the effect of improving the single-pass conversion rate. In addition, the product does not contain COx produced by deep oxidation, has high olefin selectivity, and has the only by-product being water, which is easily compatible with existing industrial processes. It is currently the most promising method for propane oxidative dehydrogenation, but existing catalysts have problems such as low oxygen carrier loading and insufficient dehydrogenation activity that have not yet been resolved. The present invention discloses a propane oxidative dehydrogenation catalyst that may contain an oxygen carrier component. By optimizing the dehydrogenation activity, the catalyst has an improved conversion rate compared to a general direct dehydrogenation catalyst under similar propylene selectivity. Compared to a general oxidative dehydrogenation catalyst containing an oxygen carrier, the catalyst has a significantly improved selectivity under similar conversion rates. Therefore, the catalyst has good prospects for process application. Summary of the Invention

[0004] To address the above-mentioned issues, the present application proposes, on the one hand, a method for synthesizing a propane oxidative dehydrogenation catalyst, comprising the following steps: preparing a zirconium-based gel powder; mixing a chromium solution with the zirconium-based gel powder to obtain an active substance; mixing and shaping the active substance, a modified metal oxide, and an inert carrier, followed by drying, calcining, and reducing to obtain a propane oxidative dehydrogenation catalyst. The present application adopts a precipitation method to prepare the active carrier and the catalytically active substance separately, and then mixes and shapes the active substance, the modified metal oxide, and the inert carrier, drying, and calcining to prepare a shaped catalyst, thereby fully exerting the catalytic performance of the active substance. The inert carrier ensures stability, and the modified metal oxide ensures the provision of as many reaction sites as possible.

[0005] Preferably, the zirconium-based gel powder is synthesized as follows:

[0006] preparing a zirconium salt aqueous solution and a rare earth salt solution;

[0007] The zirconium salt aqueous solution and the rare earth salt solution are mixed and heated, and then a precipitant is added;

[0008] After precipitation, the zirconium-based gel powder is filtered, washed, dried, and ground. The zirconium salt and rare earth salt of the present application are mixed to form a gel state, which provides sufficient loading and reaction sites for subsequent loading and oxidation. The gel also has a good oxidation effect, which helps the oxidative dehydrogenation reaction proceed.

[0009] Preferably, the zirconium-based gel powder is synthesized in the following manner:

[0010] Prepare zirconium salt aqueous solution and rare earth salt solution as follows:

[0011] Prepare a zirconium salt aqueous solution, wherein the zirconium salt may be one or more of zirconium nitrate, zirconium oxynitrate, and zirconium oxychloride, and the zirconium concentration is 0.1-1 mol / L, and heat to 70-90°C for 30 minutes;

[0012] Prepare a rare earth salt solution of one or more of yttrium nitrate, scandium nitrate, and cerium nitrate, with a concentration of 0.1-1 mol / L, heat to 70-90°C, and maintain for 30 minutes;

[0013] The zirconium salt aqueous solution and the rare earth salt solution are mixed and heated as follows, and then a precipitant is added:

[0014] The two solutions were mixed, maintained at the temperature, and continued to heat for 30 minutes, with the mass ratio of rare earth salt measured in rare earth: zirconium salt measured in zirconium = 0.8-0.9;

[0015] Adding a precipitant under heating and stirring conditions, wherein the precipitant is one or more of ammonia water, sodium hydroxide, and potassium hydroxide;

[0016] Add dropwise at a uniform rate until the solution pH is > 10, continue stirring for 30 minutes, then stop stirring and heating, and let the slurry stand naturally for 8-12 hours. The volume ratio of the precipitant solution to the salt solution is 0.2-1;

[0017] After precipitation, the zirconium-based gel powder is obtained by filtering, washing, drying and grinding in the following manner:

[0018] The slurry was filtered and washed with deionized water, and the washing was stopped when the filtrate reached pH = 7;

[0019] The obtained gel is dried under ventilation at 110° C. for 4-12 hours to obtain a solid, which is then ground into a powder with a particle size of less than 200 meshes.

[0020] Preferably, the active substance is obtained as follows:

[0021] The chromium solution and zirconium-based gel powder are mixed by ball milling;

[0022] The mixture is ball-milled and then dried, and then ground and calcined to obtain the active material.

[0023] Preferably, the chromium solution and the zirconium-based gel powder are ball-milled and mixed as follows;

[0024] The chromium salt is selected from one or more of chromium nitrate, potassium chromate and ammonium chromate;

[0025] Mix chromium salt and zirconium-based gel powder in a mass ratio of 0.1-0.5, add water in a water-to-material ratio of 0.1-0.5, grind by ball milling and mix until uniform, for at least 15 minutes;

[0026] The ball-milled mixed material is dried, then ground and calcined to obtain the active material in the following manner. The active material of this application is essentially prepared by ball-milling and loading, retaining the zirconium-based gel powder framework component while mixing the chromium salt therein. Thus, the effectiveness of the loading and mixing is ensured in the catalyst microstructure.

[0027] The ball-milled mixture is dried at 110°C for 4-12 hours through ventilation, and then fully ground to particles with a mesh size of less than 40 mesh;

[0028] After air roasting, the roasting temperature is 200-400℃ and the time is 2-4 hours;

[0029] Then grind again to a powder with a mesh size of less than 200 mesh to obtain the active substance.

[0030] Preferably, the modified metal oxide is obtained as follows:

[0031] Mixing metal oxide, silicon source, template, additive and solvent;

[0032] The mass ratio of metal oxide: silicon source: template: additive: solvent is 20:40:10:5:100;

[0033] Performing a hydrothermal reaction;

[0034] drying the hydrothermal reaction product;

[0035] After drying, sodium tungstate impregnation is performed;

[0036] After impregnation, the mixture is dried and ground to obtain the modified oxide. This application uses a hydrothermal reaction to obtain a metal oxide containing a silicon source, and then uses sodium tungstate for surface modification, which can ensure that a strong bond can be generated in the subsequent loading of the active substance, ensuring the stability of the catalyst itself during use.

[0037] Preferably, the metal oxide, silicon source, template, auxiliary agent and solvent are mixed as follows:

[0038] The metal oxide particles are fully ground to a particle size of less than 400 mesh, wherein the metal oxide is manganese oxide, molybdenum oxide or cobalt oxide;

[0039] Adding a silicon source, wherein the silicon source is ethyl orthosilicate or methyl orthosilicate;

[0040] Adding a template, the template is CTAB or TPOH;

[0041] Adding an auxiliary agent, which is urea, ammonium bicarbonate or triethanolamine;

[0042] Adding a solvent, which is a mixed solvent of water and ethanol in a volume ratio of 1:1;

[0043] The hydrothermal reaction was carried out as follows:

[0044] After stirring thoroughly at 60-80°C for 10 minutes, the mixture was aged for 4 hours and then subjected to hydrothermal reaction at 120-160°C for 12 hours before cooling. The obtained solid was filtered and washed with deionized water until the pH was less than 7.

[0045] The hydrothermal reaction product is dried as follows;

[0046] Dry at 110°C for 4-12 hours;

[0047] The dried sodium tungstate was impregnated as follows;

[0048] Prepare a sodium tungstate aqueous solution with a concentration of 0.1 mol / L, then immerse the dried material in the sodium tungstate aqueous solution for 2-3 hours;

[0049] The modified oxide is obtained by drying and grinding after impregnation as follows;

[0050] The modified oxide is dried at 110° C. for 4-12 hours through ventilation, and then ground and sieved to obtain particles with a particle size of less than 400 meshes.

[0051] Preferably, the propane oxidative dehydrogenation catalyst is synthesized as follows:

[0052] The active material, modified metal oxide, inert carrier and binder are fully mixed;

[0053] After being fully mixed, the mixture is rolled using a roller compactor and then extruded into a mold;

[0054] Then drying and sieving;

[0055] Then, the catalyst is subjected to primary calcination, secondary calcination and reduction to obtain the propane oxidative dehydrogenation catalyst.

[0056] Preferably, the active material, modified metal oxide, inert carrier, and binder are thoroughly mixed in the following manner;

[0057] The active material and the modified metal oxide are fully mixed, and an inert component is added as an auxiliary carrier, wherein the inert component is kaolin, montmorillonite or fumed silica;

[0058] Adding an inorganic binder, wherein the inorganic binder is a silica sol solution, an aluminum sol solution, or a silica-alumina sol solution;

[0059] adding a pore-forming agent, wherein the pore-forming agent is sesbania powder, guar gum powder or starch;

[0060] Mix with a plow mixer for at least 15 minutes.

[0061] After being fully mixed in the following manner, the mixture is rolled using a roller compactor, and then extruded into a mold;

[0062] The catalyst is rolled with a roller compactor at a pressure of not less than 2 MPa for at least 10 minutes and extruded with a screw extruder to form a strip or clover-shaped catalyst with a diameter of X and a length of Y, where X is 1.5-9 mm and 2X <Y<10X;

[0063] Drying and sieving are carried out as follows;

[0064] Air dry at 110°C for 4-12 hours, then remove the fine powder and small particles by sieving, the sieve used for sieving is 20 mesh;

[0065] The propane oxidative dehydrogenation catalyst is obtained by performing primary calcination, secondary calcination, and reduction as follows;

[0066] Calcination in air at 400-600℃ for 1-4 hours, and secondary calcination at 600-800℃ for 2-6 hours;

[0067] The reducing atmosphere is H2 / N2 with a volume ratio of 30 / 70, a temperature of 300-500°C, a mass space velocity of 1-4 / hour, and is continued for 2-6 hours, and then cooled to room temperature to obtain a propane oxidative dehydrogenation catalyst.

[0068] Preferably, when fully mixed, the mass proportions of the various substances are as follows: active substance: 2-20 parts; modified metal oxide: 10-60 parts; inert component: 20-60 parts; inorganic binder: 5-30 parts; pore former: 3-20 parts; water: 50-100 parts.

[0069] On the other hand, the present application also proposes a propane oxidative dehydrogenation catalyst and the use of the propane oxidative dehydrogenation catalyst in propane oxidative dehydrogenation.

[0070] This application can bring the following beneficial effects:

[0071] 1. This application adopts a precipitation method to prepare the active support and catalytically active material separately, and then the active material, modified metal oxide, and inert support are mixed, shaped, dried, and calcined to prepare a shaped catalyst, so that the catalytic performance of the active material can be fully exerted. The catalytically active component is used to convert propane, the inert support increases the strength and thermal stability of the catalyst, and the modified metal oxide can react with the hydrogen generated during the reaction, promote the forward shift of the reaction equilibrium, and act as an active auxiliary agent.

[0072] 2. After the zirconium salt and rare earth salt of the present application are mixed, a gel state is obtained, which provides sufficient load and reaction sites for subsequent loading and oxidation effects. It also has a certain oxidation effect, which helps the oxidative dehydrogenation reaction.

[0073] 3. The active material of the present application is essentially prepared by ball milling and loading. While retaining the zirconium-based gel powder framework component, the chromium salt is mixed therein. Therefore, the effectiveness of the loading and mixing is guaranteed in the microstructure of the catalyst.

[0074] 4. The present application adopts a hydrothermal reaction to obtain a metal oxide containing micro-mesoporous silica, and then uses sodium tungstate for surface modification, which can ensure that a strong bond can be generated in the later loading of the active substance, and ensure the stability of the metal oxide itself during the repeated oxidation-reduction process during use.

[0075] 5. The catalyst preparation process of the present application adopts two calcinations and a hydrogen pre-reduction process, which can ensure that the catalyst has sufficient mechanical strength and high initial reaction activity. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0077] Figure 1 is the SEM image of catalyst No. 1;

[0078] Figure 2 is the SEM image of catalyst No. 2;

[0079] Figure 3 is the SEM image of catalyst No. 3;

[0080] Figure 4 is the SEM image of catalyst No. 4;

[0081] Figure 5 This is the SEM image of catalyst No. 5. DETAILED DESCRIPTION

[0082] In order to clearly illustrate the technical features of this solution, this application is described in detail below through specific implementation methods and in conjunction with its accompanying drawings.

[0083] In a first embodiment, a method for synthesizing a propane oxidative dehydrogenation catalyst comprises the following steps:

[0084] S1. Preparation of zirconium-based gel powder;

[0085] S101 prepares zirconium salt aqueous solution and rare earth salt solution:

[0086] Prepare a zirconium salt aqueous solution, wherein the zirconium salt may be one or more of zirconium nitrate, zirconium oxynitrate, and zirconium oxychloride, and the zirconium concentration is 0.1-1 mol / L, and heat to 70-90°C for 30 minutes;

[0087] Prepare a rare earth salt solution of one or more of yttrium nitrate, scandium nitrate, and cerium nitrate, with a concentration of 0.1-1 mol / L, heat to 70-90°C, and maintain for 30 minutes;

[0088] S102: Mix and heat the zirconium salt solution and the rare earth salt solution, and then add a precipitant:

[0089] The two solutions were mixed, maintained at the temperature, and continued to heat for 30 minutes, with the mass ratio of rare earth salt measured in rare earth: zirconium salt measured in zirconium = 0.8-0.9;

[0090] Adding a precipitant under heating and stirring conditions, wherein the precipitant is one or more of ammonia water, sodium hydroxide, and potassium hydroxide;

[0091] Add dropwise at a uniform rate until the solution pH is > 10, continue stirring for 30 minutes, then stop stirring and heating, and let the slurry stand naturally for 8-12 hours. The volume ratio of the precipitant solution to the salt solution is 0.2-1;

[0092] After precipitation, S103 is filtered, washed, dried, and ground to obtain zirconium-based gel powder:

[0093] The slurry was filtered and washed with deionized water, and the washing was stopped when the filtrate reached pH = 7;

[0094] The obtained gel is dried under ventilation at 110° C. for 4-12 hours to obtain a solid, which is then ground into a powder with a particle size of less than 200 meshes.

[0095] S2. The chromium solution was mixed with the zirconium-based gel powder to obtain an active substance;

[0096] S201 ball-milling the chromium solution and the zirconium-based gel powder;

[0097] The chromium salt is selected from one or more of chromium nitrate, potassium chromate and ammonium chromate;

[0098] Mix chromium salt and zirconium-based gel powder in a mass ratio of 0.1-0.5, add water in a water-to-material ratio of 0.1-0.5, grind by ball milling and mix until uniform, for at least 15 minutes;

[0099] S202 dries the ball-milled mixed material, and then grinds and roasts it to obtain an active substance.

[0100] The ball-milled mixture is dried at 110°C for 4-12 hours through ventilation, and then fully ground to particles with a mesh size of less than 40 mesh;

[0101] After air roasting, the roasting temperature is 200-400℃ and the time is 2-4 hours;

[0102] Then grind again to a powder with a mesh size of less than 200 mesh to obtain the active substance.

[0103] S3. Preparation of modified metal oxides.

[0104] S301: mixing metal oxide, silicon source, template, additive and solvent;

[0105] The mass ratio of metal oxide: silicon source: template: additive: solvent is 20:40:10:5:100;

[0106] The metal oxide particles are fully ground to a particle size of less than 400 mesh, wherein the metal oxide is manganese oxide, molybdenum oxide or cobalt oxide;

[0107] Adding a silicon source, wherein the silicon source is ethyl orthosilicate or methyl orthosilicate;

[0108] Adding a template, the template is CTAB or TPOH;

[0109] Adding an auxiliary agent, which is urea, ammonium bicarbonate or triethanolamine;

[0110] Adding a solvent, which is a mixed solvent of water and ethanol in a volume ratio of 1:1;

[0111] S302 performs a hydrothermal reaction;

[0112] After stirring thoroughly at 60-80°C for 10 minutes, the mixture was aged for 4 hours and then subjected to hydrothermal reaction at 120-160°C for 12 hours before cooling. The obtained solid was filtered and washed with deionized water until the pH was less than 7.

[0113] S303 drying the hydrothermal reaction product;

[0114] Dry at 110°C for 4-12 hours;

[0115] After S304 is dried, it is impregnated with sodium tungstate;

[0116] Prepare a sodium tungstate aqueous solution with a concentration of 0.1 mol / L, then immerse the dried material in the sodium tungstate aqueous solution for 2-3 hours;

[0117] After S305 impregnation, the mixture is dried and ground to obtain a modified oxide.

[0118] The modified oxide is obtained by drying and grinding after impregnation as follows;

[0119] The modified oxide is dried at 110° C. for 4-12 hours through ventilation, and then ground and sieved to obtain particles with a particle size of less than 400 meshes.

[0120] S4. The active material, the modified metal oxide, and the inert carrier are mixed and formed, and then dried, calcined, and reduced to obtain a propane oxidative dehydrogenation catalyst.

[0121] S401: fully mixing the active material, modified metal oxide, inert carrier, and binder;

[0122] The active material and the modified metal oxide are fully mixed, and an inert component is added as an auxiliary carrier, wherein the inert component is kaolin, montmorillonite or fumed silica. When fully mixed, the mass proportions of each substance are as follows: active material: 2-20 parts; modified metal oxide: 10-60 parts; inert component: 20-60 parts; inorganic binder: 5-30 parts; pore former: 3-20 parts; water: 50-100 parts.

[0123] Adding an inorganic binder, wherein the inorganic binder is a silica sol solution, an aluminum sol solution, or a silica-alumina sol solution;

[0124] adding a pore-forming agent, wherein the pore-forming agent is sesbania powder, guar gum powder or starch;

[0125] Mix with a plow mixer for at least 15 minutes.

[0126] S402 is fully mixed and then rolled using a roller, and then extruded and formed;

[0127] The catalyst is rolled with a roller compactor at a pressure of not less than 2 MPa for at least 10 minutes and extruded with a screw extruder to form a strip or clover-shaped catalyst with a diameter of X and a length of Y, where X is 1.5-9 mm and 2X <Y<10X;

[0128] S403 then performs drying and screening;

[0129] Air dry at 110°C for 4-12 hours, then remove the fine powder and small particles by sieving, the sieve used for sieving is 20 mesh;

[0130] S404 then performs primary calcination, secondary calcination, and reduction to obtain a propane oxidative dehydrogenation catalyst.

[0131] Calcination in air at 400-600℃ for 1-4 hours, and secondary calcination at 600-800℃ for 2-6 hours;

[0132] The reducing atmosphere is H2 / N2 with a volume ratio of 30 / 70, a temperature of 300-500°C, a mass space velocity of 1-4 / hour, and is continued for 2-6 hours, and then cooled to room temperature to obtain a propane oxidative dehydrogenation catalyst.

[0133] The propane oxidative dehydrogenation catalyst prepared by the method and the application of the propane oxidative dehydrogenation catalyst in propane oxidative dehydrogenation have good selectivity and catalytic performance.

[0134] According to the above method, the following examples are made to illustrate the catalytic performance of the obtained catalyst.

[0135] Example 1:

[0136] S11. Preparation of zirconium-based gel powder;

[0137] S1101 Preparation of zirconium salt aqueous solution and rare earth salt solution:

[0138] Prepare a zirconium salt aqueous solution of zirconium nitrate with a zirconium concentration of 0.1 mol / L, heat to 70°C, and maintain for 30 minutes;

[0139] Prepare a rare earth salt solution of yttrium nitrate with a concentration of 0.1 mol / L, heat to 70°C, and maintain for 30 minutes;

[0140] S1102: Mix and heat the zirconium salt solution and the rare earth salt solution, and then add the precipitant:

[0141] The two solutions were mixed, maintained at the temperature, and heated for 30 minutes. The mass ratio of the mixture was rare earth salt measured in rare earth: zirconium salt measured in zirconium = 0.8;

[0142] Add a precipitant under heating and stirring conditions, the precipitant is ammonia water (saturated);

[0143] Add dropwise at a uniform rate until the pH of the solution is >10, continue stirring for 30 minutes, then stop stirring and heating, and let the slurry stand naturally for 8 hours. The volume ratio of the precipitant solution to the salt solution is 0.2;

[0144] After precipitation, S1103 is filtered, washed, dried, and ground to obtain zirconium-based gel powder:

[0145] The slurry was filtered and washed with deionized water, and the washing was stopped when the filtrate reached pH = 7;

[0146] The obtained gel was dried under ventilation at 110° C. for 4 hours to obtain a solid, which was then ground into a powder with a particle size of less than 200 mesh.

[0147] S12. The chromium solution is mixed with the zirconium-based gel powder to obtain an active substance;

[0148] S1201 ball-milling the chromium solution and the zirconium-based gel powder;

[0149] The chromium salt is chromium nitrate;

[0150] Mix chromium salt and zirconium-based gel powder at a mass ratio of 0.1, add water at a water-to-material ratio of 0.1, grind and mix until uniform using a ball mill for at least 15 minutes;

[0151] S1202 dries the ball-milled mixed material, and then grinds and roasts it to obtain an active substance.

[0152] The ball-milled mixture was dried at 110°C for 4 hours under ventilation, and then fully ground to particles with a mesh size of less than 40 mesh;

[0153] After air roasting, the roasting temperature is 200℃ and the time is 4 hours;

[0154] Then grind again to a powder with a mesh size of less than 200 mesh to obtain the active substance.

[0155] S13. Preparation of modified metal oxides.

[0156] S1301: mixing metal oxide, silicon source, template, additive and solvent;

[0157] The mass ratio of metal oxide: silicon source: template: additive: solvent is 20:40:10:5:100;

[0158] grinding metal oxide particles to a particle size of less than 400 mesh, wherein the metal oxide is manganese oxide;

[0159] Adding a silicon source, wherein the silicon source is ethyl orthosilicate;

[0160] Adding a template, wherein the template is CTAB;

[0161] Adding an auxiliary agent, the auxiliary agent is urea;

[0162] Adding a solvent, which is a mixed solvent of water and ethanol in a volume ratio of 1:1;

[0163] S1302 performs a hydrothermal reaction;

[0164] After stirring thoroughly at 60-80°C for 10 minutes, the mixture was aged for 4 hours and then subjected to hydrothermal reaction at 120-160°C for 12 hours before cooling. The obtained solid was filtered and washed with deionized water until the pH was less than 7.

[0165] S1303 drying the hydrothermal reaction product;

[0166] Dry at 110°C for 4-12 hours;

[0167] After S1304 is dried, it is impregnated with sodium tungstate;

[0168] Prepare a sodium tungstate aqueous solution with a concentration of 0.1 mol / L, then immerse the dried material in the sodium tungstate aqueous solution for 2 hours;

[0169] After impregnation, S1305 is dried and ground to obtain modified oxide.

[0170] The modified oxide is obtained by drying and grinding after impregnation as follows;

[0171] The modified oxide was dried at 110° C. for 4 hours under ventilation, and then ground and sieved to obtain particles with a particle size of less than 400 meshes.

[0172] S14. The active material, the modified metal oxide, and the inert carrier are mixed and formed, and then dried, calcined, and reduced to obtain a propane oxidative dehydrogenation catalyst.

[0173] S1401: fully mix the active material, modified metal oxide, inert carrier, and binder;

[0174] The active material and the modified metal oxide are fully mixed, and an inert component is added as an auxiliary carrier, wherein the inert component is kaolin. When fully mixed, the mass proportions of each substance are as follows: active material: 2 parts; modified metal oxide: 10 parts; inert component: 20 parts; inorganic binder: 5 parts; pore-forming agent: 3 parts; water: 50 parts.

[0175] Adding an inorganic binder, wherein the inorganic binder is a silica sol solution;

[0176] adding a pore-forming agent, wherein the pore-forming agent is sesbania powder;

[0177] Mix with a plow mixer for at least 15 minutes.

[0178] After S1402 is fully mixed, it is rolled using a roller compactor and then extruded into a mold;

[0179] Use a roller roller to roll at a pressure of not less than 2 MPa for at least 10 minutes, and extrude using a screw extruder to form strips with a diameter of 2 mm and a length of 6 mm;

[0180] S1403 then performs drying and screening;

[0181] Air dry at 110°C for 4 hours, then remove the fine powder and small particles by sieving, the sieve used for sieving is 20 mesh;

[0182] S1404 then performs primary calcination, secondary calcination, and reduction to obtain a propane oxidative dehydrogenation catalyst.

[0183] The first calcination was carried out at 400℃ in air for 4 hours, and the second calcination was carried out at 600℃ for 6 hours;

[0184] The reducing atmosphere was H2 / N2 with a volume ratio of 30 / 70, a temperature of 300°C, a mass space velocity of 1 / hour, and continued for 6 hours, after which the temperature was lowered to room temperature to obtain catalyst No. 1.

[0185] The specific surface area of ​​catalyst No. 1 was measured to be 212 m 2 / g;

[0186] Catalyst No. 1 was used to carry out propane oxidative dehydrogenation reaction. The reaction apparatus was a fixed-bed adiabatic reaction tube. The catalyst loading was 1000 g, wherein the direct dehydrogenation catalyst was loaded in the form of 400 g of dehydrogenation active component and the remaining mass was inert porcelain balls. The total loading mass was 1000 g. The reactor had four inlet streams, namely propane-nitrogen-air-hydrogen. The embodiment adopted four steps of propane reaction-nitrogen purge-air regeneration-nitrogen purge. The reaction gas inlet temperature was 580 degrees, the pressure was normal pressure, the reaction time was 10 min, the regeneration time was 10 min, and the purge time was 2 min. The propane flow rate was 2500 ml / min, the nitrogen flow rate was 5000 ml / min, and the air flow rate was 7000 ml / min. The measured propane cumulative conversion rate was 52.1%, and the propylene selectivity was 95.2%. After 10 reaction regenerations, the specific surface area was measured again. It was 207 m 2 / g.

[0187] Example 2:

[0188] S21. Preparation of zirconium-based gel powder;

[0189] S2101 Preparation of zirconium salt aqueous solution and rare earth salt solution:

[0190] Prepare a zirconium salt aqueous solution of zirconium oxynitrate with a zirconium concentration of 1 mol / L, heat to 90°C, and maintain for 30 minutes;

[0191] Prepare a rare earth salt solution of scandium nitrate with a concentration of 1 mol / L, heat to 90°C, and maintain for 30 minutes;

[0192] S2102 Mix and heat the zirconium salt solution and rare earth salt solution, then add the precipitant:

[0193] The two solutions were mixed, maintained at the temperature, and continued to heat for 30 minutes. The mass ratio of the mixture was rare earth salt measured in rare earth: zirconium salt measured in zirconium = 0.9;

[0194] A precipitant was added under heating and stirring conditions, wherein the precipitant was sodium hydroxide (1 mol / L);

[0195] Add dropwise at a uniform rate until the pH of the solution is >10, continue stirring for 30 minutes, then stop stirring and heating, and let the slurry stand naturally for 12 hours. The volume ratio of the precipitant solution to the salt solution is 1;

[0196] After precipitation, S2103 is filtered, washed, dried, and ground to obtain zirconium-based gel powder:

[0197] The slurry was filtered and washed with deionized water, and the washing was stopped when the filtrate reached pH = 7;

[0198] The obtained gel is dried under ventilation at 110° C. for 4-12 hours to obtain a solid, which is then ground into a powder with a particle size of less than 200 meshes.

[0199] S22. The chromium solution is mixed with the zirconium-based gel powder to obtain an active substance;

[0200] S2201 ball-milling the chromium solution and the zirconium-based gel powder;

[0201] The chromium salt is potassium chromate;

[0202] Mix chromium salt and zirconium-based gel powder at a mass ratio of 0.5, add water at a water-to-material ratio of 0.5, grind by ball milling and mix until uniform, for at least 15 minutes;

[0203] S2202 dries the ball-milled mixed material, and then grinds and roasts it to obtain the active material.

[0204] The ball-milled mixture was dried at 110°C for 12 hours under ventilation, and then fully ground to particles with a mesh size of less than 40 mesh;

[0205] After air calcination, the calcination temperature is 400℃ and the time is 2 hours;

[0206] Then grind again to a powder with a mesh size of less than 200 mesh to obtain the active substance.

[0207] S23. Preparation of modified metal oxides.

[0208] S2301: mixing metal oxide, silicon source, template, additive and solvent;

[0209] The mass ratio of metal oxide: silicon source: template: additive: solvent is 20:40:10:5:100;

[0210] grinding metal oxide particles to a particle size of less than 400 mesh, wherein the metal oxide is copper oxide;

[0211] Adding a silicon source, wherein the silicon source is methyl orthosilicate;

[0212] Adding a template, the template is TPOH;

[0213] Adding an auxiliary agent, the auxiliary agent is ammonium bicarbonate;

[0214] Adding a solvent, which is a mixed solvent of water and ethanol in a volume ratio of 1:1;

[0215] S2302 performs hydrothermal reaction;

[0216] After being stirred at 80°C for 10 minutes, the mixture was aged for 4 hours and then subjected to a hydrothermal reaction at 160°C for 12 hours before being cooled. The obtained solid was filtered and washed with deionized water until the pH was less than 7.

[0217] S2303 drying the hydrothermal reaction product;

[0218] Dry at 110°C for 12 hours;

[0219] After drying, S2304 is impregnated with sodium tungstate;

[0220] Prepare a sodium tungstate aqueous solution with a concentration of 0.1 mol / L, then immerse the dried material in the sodium tungstate aqueous solution for 3 hours;

[0221] After impregnation, S2305 is dried and ground to obtain modified oxide.

[0222] The modified oxide is obtained by drying and grinding after impregnation as follows;

[0223] The modified oxide was dried at 110° C. for 12 hours through ventilation, and then ground and sieved to obtain particles with a particle size of less than 400 meshes.

[0224] S24. The active material, the modified metal oxide, and the inert carrier are mixed and formed, and then dried, calcined, and reduced to obtain a propane oxidative dehydrogenation catalyst.

[0225] S2401: fully mix the active material, modified metal oxide, inert carrier, and binder;

[0226] The active material and the modified metal oxide are fully mixed, and an inert component is added as an auxiliary carrier, wherein the inert component is montmorillonite. When fully mixed, the mass fractions of each substance are as follows: active material: 20 parts; modified metal oxide: 60 parts; inert component: 60 parts; inorganic binder: 30 parts; pore former: 20 parts; water: 100 parts.

[0227] Adding an inorganic binder, wherein the inorganic binder is an aluminum sol solution;

[0228] Adding a pore-forming agent, wherein the pore-forming agent is guar gum powder;

[0229] Mix with a plow mixer for at least 15 minutes.

[0230] After S2402 is fully mixed, it is rolled using a roller compactor and then extruded into a mold;

[0231] Use a roller roller to roll at a pressure of not less than 2 MPa for at least 10 minutes, and extrude using a screw extruder to form strips with a diameter of 2 mm and a length of 6 mm;

[0232] S2403 then performs drying and screening;

[0233] Air dry at 110°C for 12 hours, then remove the fine powder and small particles by sieving, the sieve used for sieving is 20 mesh;

[0234] S2404 is then subjected to primary calcination, secondary calcination, and reduction to obtain a propane oxidative dehydrogenation catalyst.

[0235] The steel was calcined in air at 600°C for 1 hour and then calcined again at 800°C for 2 hours.

[0236] The reducing atmosphere was H2 / N2 with a volume ratio of 30 / 70, a temperature of 500°C, a mass space velocity of 4 / hour, and continued for 2 hours, after which the temperature was lowered to room temperature to obtain catalyst No. 2.

[0237] The specific surface area of ​​catalyst No. 2 was measured to be 237 m 2 / g;

[0238] Catalyst No. 2 was used to carry out propane oxidative dehydrogenation reaction. The reaction apparatus was a fixed-bed adiabatic reaction tube. The catalyst loading was 1000 g, wherein the direct dehydrogenation catalyst was loaded in the form of 400 g of dehydrogenation active component and the remaining mass was inert porcelain balls. The total loading mass was 1000 g. The reactor had four inlet streams, namely propane-nitrogen-air-hydrogen. The embodiment adopted four steps of propane reaction-nitrogen purge-air regeneration-nitrogen purge. The reaction gas inlet temperature was 580 degrees, the pressure was normal pressure, the propane reaction time was 10 min, the air regeneration time was 10 min, and the purge time was 2 min. The propane flow rate was 2500 ml / min, the nitrogen flow rate was 5000 ml / min, and the air flow rate was 7000 ml / min. The measured propane conversion rate was 53.3%, and the propylene selectivity was 91.4%. After 10 times of reaction and regeneration, the specific surface area was measured again and was 233 m 2 / g.

[0239] Example 3:

[0240] S31. Preparation of zirconium-based gel powder;

[0241] S3101 Preparation of zirconium salt aqueous solution and rare earth salt solution:

[0242] Prepare a zirconium salt aqueous solution of zirconium oxychloride with a zirconium concentration of 0.5 mol / L, heat to 80°C and maintain for 30 minutes;

[0243] Prepare a rare earth salt solution of cerium nitrate with a concentration of 0.5 mol / L, heat to 80°C and maintain for 30 minutes;

[0244] S3102 Mix and heat the zirconium salt solution and rare earth salt solution, then add the precipitant:

[0245] The two solutions were mixed, maintained at the temperature, and heated for 30 minutes. The mass ratio of the mixture was rare earth salt measured in rare earth: zirconium salt measured in zirconium = 0.8;

[0246] A precipitant was added under heating and stirring conditions, wherein the precipitant was potassium hydroxide (1 mol / L);

[0247] Add dropwise at a uniform rate until the pH of the solution is >10, continue stirring for 30 minutes, then stop stirring and heating, and let the slurry stand naturally for 10 hours. The volume ratio of the precipitant solution to the salt solution is 0.6;

[0248] After precipitation, S3103 is filtered, washed, dried, and ground to obtain zirconium-based gel powder:

[0249] The slurry was filtered and washed with deionized water, and the washing was stopped when the filtrate reached pH = 7;

[0250] The obtained gel was dried under ventilation at 110° C. for 8 hours to obtain a solid, which was then ground into a powder with a particle size of less than 200 meshes.

[0251] S32. The chromium solution was mixed with the zirconium-based gel powder to obtain an active substance;

[0252] S3201 ball-milling the chromium solution and the zirconium-based gel powder;

[0253] The chromium salt is ammonium chromate;

[0254] Mix chromium salt and zirconium-based gel powder at a mass ratio of 0.3, add water at a water-to-material ratio of 0.3, grind by ball milling and mix until uniform, for at least 15 minutes;

[0255] S3202 dries the ball-milled mixed material, and then grinds and roasts it to obtain an active substance.

[0256] The ball-milled mixture was dried at 110°C for 8 hours under ventilation, and then fully ground to particles with a mesh size of less than 40 mesh;

[0257] After air roasting, the roasting temperature is 300℃ and the time is 3 hours;

[0258] Then grind again to a powder with a mesh size of less than 200 mesh to obtain the active substance.

[0259] S33. Preparation of modified metal oxides.

[0260] S3301: mixing metal oxide, silicon source, template, additive and solvent;

[0261] The mass ratio of metal oxide: silicon source: template: additive: solvent is 20:40:10:5:100;

[0262] The metal oxide particles are fully ground to a particle size of less than 400 mesh, wherein the metal oxide is tungsten oxide;

[0263] Adding a silicon source, wherein the silicon source is ethyl orthosilicate;

[0264] Adding a template, wherein the template is CTAB;

[0265] Adding an auxiliary agent, wherein the auxiliary agent is triethanolamine;

[0266] Adding a solvent, which is a mixed solvent of water and ethanol in a volume ratio of 1:1;

[0267] S3302 performs a hydrothermal reaction;

[0268] After stirring thoroughly at 60-80°C for 10 minutes, the mixture was aged for 4 hours and then subjected to a hydrothermal reaction at 140°C for 12 hours before cooling. The obtained solid was filtered and washed with deionized water until the pH was less than 7.

[0269] S3303 drying the hydrothermal reaction product;

[0270] Dry at 110°C for 8 hours;

[0271] After drying, S3304 is impregnated with sodium tungstate;

[0272] Prepare a sodium tungstate aqueous solution with a concentration of 0.1 mol / L, then immerse the dried material in the sodium tungstate aqueous solution for 2.5 hours;

[0273] After impregnation, S3305 is dried and ground to obtain modified oxide.

[0274] The modified oxide is obtained by drying and grinding after impregnation as follows;

[0275] The modified oxide was dried at 110° C. for 8 hours under ventilation, and then ground and sieved to obtain particles with a particle size of less than 400 meshes.

[0276] S34. The active material, modified metal oxide, and inert carrier are mixed and formed, and then dried, calcined, and reduced to obtain a propane oxidative dehydrogenation catalyst.

[0277] S3401: fully mix the active material, modified metal oxide, inert carrier, and binder;

[0278] The active material and the modified metal oxide are fully mixed, and an inert component is added as an auxiliary carrier, wherein the inert component is fumed silica. When fully mixed, the mass fractions of each substance are as follows: active material: 10 parts; modified metal oxide: 40 parts; inert component: 40 parts; inorganic binder: 18 parts; pore former: 12 parts; water: 80 parts.

[0279] Adding an inorganic binder, wherein the inorganic binder is a silica-alumina sol solution;

[0280] Adding a pore-forming agent, wherein the pore-forming agent is starch;

[0281] Mix with a plow mixer for at least 15 minutes.

[0282] After S3402 is fully mixed, it is rolled using a roller compactor and then extruded into a mold;

[0283] Use a roller roller to roll at a pressure of not less than 2 MPa for at least 10 minutes, and extrude using a screw extruder to form strips with a diameter of 2 mm and a length of 6 mm;

[0284] S3403 then performs drying and screening;

[0285] Air dry at 110°C for 8 hours, then remove the fine powder and small particles by sieving, the sieve used for sieving is 20 mesh;

[0286] S3404 is then subjected to primary calcination, secondary calcination, and reduction to obtain a propane oxidative dehydrogenation catalyst.

[0287] The steel was calcined in air at 500°C for 2 hours and then calcined again at 700°C for 4 hours.

[0288] The reducing atmosphere was H2 / N2 with a volume ratio of 30 / 70, a temperature of 400°C, a mass space velocity of 2 / hour, and continued for 4 hours, after which the temperature was lowered to room temperature to obtain catalyst No. 3.

[0289] The specific surface area of ​​catalyst No. 3 was measured to be 229 m 2 / g;

[0290] Catalyst No. 3 was used to carry out propane oxidative dehydrogenation reaction. The reaction apparatus was a fixed-bed adiabatic reaction tube. The catalyst loading was 1000 g, wherein the direct dehydrogenation catalyst was loaded in the form of 400 g of dehydrogenation active component and the remaining mass was inert porcelain balls. The total loading mass was 1000 g. The reactor had four inlet streams, namely propane-nitrogen-air-hydrogen. The embodiment adopted four steps of propane reaction-nitrogen purge-air regeneration-nitrogen purge. The reaction gas inlet temperature was 580 degrees, the pressure was normal pressure, the propane reaction time was 10 min, the air regeneration time was 10 min, and the purge time was 2 min. The propane flow rate was 2500 ml / min, the nitrogen flow rate was 5000 ml / min, the air flow rate was 7000 ml / min, and the hydrogen flow rate was 3000 ml / min. The measured propane conversion rate was 48.8%, and the propylene selectivity was 87.7%. After 10 reaction regenerations, the specific surface area was measured again. It was 224 m 2 / g.

[0291] Comparative Example 1:

[0292] S41. Preparation of zirconium-based gel powder;

[0293] S4101 Preparation of zirconium salt aqueous solution and rare earth salt solution:

[0294] Prepare a zirconium salt aqueous solution of zirconium oxychloride with a zirconium concentration of 0.5 mol / L, heat to 80°C and maintain for 30 minutes;

[0295] Prepare a rare earth salt solution of cerium nitrate with a concentration of 0.5 mol / L, heat to 80°C and maintain for 30 minutes;

[0296] S4102 Mix and heat the zirconium salt solution and rare earth salt solution, then add the precipitant:

[0297] The two solutions were mixed, maintained at the temperature, and heated for 30 minutes. The mass ratio of the mixture was rare earth salt measured in rare earth: zirconium salt measured in zirconium = 0.8;

[0298] A precipitant was added under heating and stirring conditions, wherein the precipitant was potassium hydroxide (1 mol / L);

[0299] Add dropwise at a uniform rate until the pH of the solution is >10, continue stirring for 30 minutes, then stop stirring and heating, and let the slurry stand naturally for 10 hours. The volume ratio of the precipitant solution to the salt solution is 0.6;

[0300] After precipitation, S4103 is filtered, washed, dried, and ground to obtain zirconium-based gel powder:

[0301] The slurry was filtered and washed with deionized water, and the washing was stopped when the filtrate reached pH = 7;

[0302] The obtained gel was dried under ventilation at 110° C. for 8 hours to obtain a solid, which was then ground into a powder with a particle size of less than 200 meshes.

[0303] S42. The chromium solution is mixed with the zirconium-based gel powder to obtain an active substance;

[0304] S4201 ball-milling the chromium solution and the zirconium-based gel powder;

[0305] The chromium salt is ammonium chromate;

[0306] Mix chromium salt and zirconium-based gel powder at a mass ratio of 0.3, add water at a water-to-material ratio of 0.3, grind by ball milling and mix until uniform, for at least 15 minutes;

[0307] S4202 dries the ball-milled mixed material, and then grinds and roasts it to obtain the active material.

[0308] The ball-milled mixture was dried at 110°C for 8 hours under ventilation, and then fully ground to particles with a mesh size of less than 40 mesh;

[0309] After air roasting, the roasting temperature is 300℃ and the time is 3 hours;

[0310] Then grind again to a powder with a mesh size of less than 200 mesh to obtain the active substance.

[0311] S43. The active material, metal oxide, and inert carrier are mixed and formed, and then dried, calcined, and reduced to obtain a propane oxidative dehydrogenation catalyst.

[0312] S4301: fully mix the active material, metal oxide, inert carrier and binder;

[0313] The active material and metal oxide (tungsten oxide) are fully mixed, and an inert component is added as an auxiliary carrier, wherein the inert component is fumed silica. When fully mixed, the mass fractions of each substance are as follows: active material: 10 parts; metal oxide: 40 parts; inert component: 40 parts; inorganic binder: 18 parts; pore-forming agent: 12 parts; water: 80 parts.

[0314] Adding an inorganic binder, wherein the inorganic binder is a silica-alumina sol solution;

[0315] Adding a pore-forming agent, wherein the pore-forming agent is starch;

[0316] Mix with a plow mixer for at least 15 minutes.

[0317] After S4302 is fully mixed, it is rolled using a roller compactor and then extruded into a mold;

[0318] Use a roller roller to roll at a pressure of not less than 2 MPa for at least 10 minutes, and extrude using a screw extruder to form strips with a diameter of 2 mm and a length of 6 mm;

[0319] S4303 then performs drying and screening;

[0320] Air dry at 110°C for 8 hours, then remove the fine powder and small particles by sieving, the sieve used for sieving is 20 mesh;

[0321] S4304 is then subjected to primary calcination, secondary calcination, and reduction to obtain a propane oxidative dehydrogenation catalyst.

[0322] The steel was calcined in air at 500°C for 2 hours and then calcined again at 700°C for 4 hours.

[0323] The reducing atmosphere was H2 / N2 with a volume ratio of 30 / 70, a temperature of 400°C, a mass space velocity of 2 / hour, and continued for 4 hours, after which the temperature was lowered to room temperature to obtain catalyst No. 4.

[0324] The specific surface area of ​​catalyst No. 4 was measured to be 132 m 2 / g;

[0325] The propane oxidative dehydrogenation reaction was carried out using catalyst No. 4. The reaction apparatus was a fixed-bed adiabatic reaction tube. The catalyst loading was 1000 g. The direct dehydrogenation catalyst loading method was 400 g of the dehydrogenation active component. The remaining mass was inert porcelain balls. The total loading mass was 1000 g. The reactor had four air inlets, namely propane-nitrogen-air-hydrogen. The comparative example used five steps: propane reaction-nitrogen purge-air regeneration-nitrogen purge-hydrogen reduction. The reaction gas inlet temperature was 580 degrees, the pressure was normal pressure, the reaction time was 10 min, the regeneration time was 10 min, and the purge and reduction time were both 2 min. The propane flow rate was 2500 ml / min, the nitrogen flow rate was 5000 ml / min, the air flow rate was 7000 ml / min, and the hydrogen flow rate was 1000 ml / min. The measured propane conversion rate was 31.8%, and the propylene selectivity was 69.1%. After 10 reactions and regenerations, the specific surface area was measured again. 88 m 2 / g.

[0326] Comparative Example 2:

[0327] S51. The chromium solution is mixed with the nano-zirconia support to obtain an active substance;

[0328] S5101 ball-milling the chromium solution and the nano-zirconia support;

[0329] The chromium salt is ammonium chromate;

[0330] Mix the chromium salt and the nano-zirconia support at a mass ratio of 0.3, add water at a water-to-material ratio of 0.3, and grind and mix until uniform using a ball mill for at least 15 minutes;

[0331] S5102 dries the ball-milled mixed material, and then grinds and roasts it to obtain the active material.

[0332] The ball-milled mixture was dried at 110°C for 8 hours under ventilation, and then fully ground to particles with a mesh size of less than 40 mesh;

[0333] After air roasting, the roasting temperature is 300℃ and the time is 3 hours;

[0334] Then grind again to a powder with a mesh size of less than 200 mesh to obtain the active substance.

[0335] S52. Preparation of modified metal oxides.

[0336] S5201: mixing metal oxide, silicon source, template, additive and solvent;

[0337] The mass ratio of metal oxide: silicon source: template: additive: solvent is 20:40:10:5:100;

[0338] The metal oxide particles are fully ground to a particle size of less than 400 mesh, wherein the metal oxide is tungsten oxide;

[0339] Adding a silicon source, wherein the silicon source is ethyl orthosilicate;

[0340] Adding a template, wherein the template is CTAB;

[0341] Adding an auxiliary agent, wherein the auxiliary agent is triethanolamine;

[0342] Adding a solvent, which is a mixed solvent of water and ethanol in a volume ratio of 1:1;

[0343] S5202 performs a hydrothermal reaction;

[0344] After stirring thoroughly at 60-80°C for 10 minutes, the mixture was aged for 4 hours and then subjected to a hydrothermal reaction at 140°C for 12 hours before cooling. The obtained solid was filtered and washed with deionized water until the pH was less than 7.

[0345] S5203 drying the hydrothermal reaction product;

[0346] Dry at 110°C for 8 hours;

[0347] After drying, S5204 is impregnated with sodium tungstate;

[0348] Prepare a sodium tungstate aqueous solution with a concentration of 0.1 mol / L, then immerse the dried material in the sodium tungstate aqueous solution for 2.5 hours;

[0349] After impregnation, S5205 is dried and ground to obtain modified oxide.

[0350] The modified oxide is obtained by drying and grinding after impregnation as follows;

[0351] The modified oxide was dried at 110° C. for 8 hours under ventilation, and then ground and sieved to obtain particles with a particle size of less than 400 meshes.

[0352] S53. The active material, the modified metal oxide, and the inert carrier are mixed and formed, and then dried, calcined, and reduced to obtain a propane oxidative dehydrogenation catalyst.

[0353] S5301: fully mix the active material, modified metal oxide, inert carrier and binder;

[0354] The active material and the modified metal oxide are fully mixed, and an inert component is added as an auxiliary carrier, wherein the inert component is fumed silica. When fully mixed, the mass fractions of each substance are as follows: active material: 10 parts; modified metal oxide: 40 parts; inert component: 40 parts; inorganic binder: 18 parts; pore former: 12 parts; water: 80 parts.

[0355] Adding an inorganic binder, wherein the inorganic binder is a silica-alumina sol solution;

[0356] Adding a pore-forming agent, wherein the pore-forming agent is starch;

[0357] Mix with a plow mixer for at least 15 minutes.

[0358] After S5302 is fully mixed, it is rolled using a roller compactor and then extruded into a mold;

[0359] Use a roller roller to roll at a pressure of not less than 2 MPa for at least 10 minutes, and extrude using a screw extruder to form strips with a diameter of 2 mm and a length of 6 mm;

[0360] S5303 then performs drying and screening;

[0361] Air dry at 110°C for 8 hours, then remove the fine powder and small particles by sieving, the sieve used for sieving is 20 mesh;

[0362] S5304 is then subjected to primary calcination, secondary calcination, and reduction to obtain a propane oxidative dehydrogenation catalyst.

[0363] The steel was calcined in air at 500°C for 2 hours and then calcined again at 700°C for 4 hours.

[0364] The reducing atmosphere was H2 / N2 with a volume ratio of 30 / 70, a temperature of 400°C, a mass space velocity of 2 / hour, and continued for 4 hours, after which the temperature was lowered to room temperature to obtain catalyst No. 5.

[0365] The specific surface area of ​​catalyst No. 5 was measured to be 179 m 2 / g;

[0366] Catalyst No. 5 was used to carry out propane oxidative dehydrogenation reaction. The reaction apparatus was a fixed-bed adiabatic reaction tube. The catalyst loading was 1000 g, wherein the direct dehydrogenation catalyst was loaded in the form of 400 g of dehydrogenation active component and the remaining mass was inert porcelain balls. The total loading mass was 1000 g. The reactor had four air inlets, namely propane-nitrogen-air-hydrogen. The embodiment adopted four steps of propane reaction-nitrogen purge-air regeneration-nitrogen purge. The reaction gas inlet temperature was 580 degrees, the pressure was normal pressure, the reaction time was 10 min, the regeneration time was 10 min, and the purge time was 2 min. The propane flow rate was 2500 ml / min, the nitrogen flow rate was 5000 ml / min, and the air flow rate was 7000 ml / min. The measured propane conversion rate was 47.1%, and the propylene selectivity was 65.8%. After use, the specific surface area was measured again, 131 m 2 / g.

[0367] The above are merely embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

Claims

1. A method for synthesizing a propane oxidative dehydrogenation catalyst, characterized in that: The steps include: preparing zirconium-based gel powder; The chromium solution is mixed with zirconium-based gel powder to load the active substance; The active material, the modified metal oxide and the inert carrier are mixed and formed, and then dried, calcined and reduced to obtain a propane oxidative dehydrogenation catalyst; The modified metal oxide is obtained as follows: Mixing metal oxide, silicon source, template, additive and solvent; The mass ratio of metal oxide: silicon source: template: additive: solvent is 20:40:10:5:100; Performing a hydrothermal reaction; drying the hydrothermal reaction product; After drying, impregnation with sodium tungstate is performed; After impregnation, the mixture is dried and ground to obtain a modified metal oxide; The metal oxide is manganese oxide, copper oxide or tungsten oxide; The inert carrier is kaolin, montmorillonite or fumed silica; The zirconium-based gel powder is synthesized as follows: preparing a zirconium salt aqueous solution and a rare earth salt solution; The zirconium salt aqueous solution and the rare earth salt solution are mixed and heated, and then a precipitant is added; After precipitation, the zirconium-based gel powder is obtained by filtering, washing, drying and grinding.

2. The method for synthesizing a propane oxidative dehydrogenation catalyst according to claim 1, wherein: Prepare zirconium salt aqueous solution and rare earth salt solution as follows: Prepare a zirconium salt aqueous solution, wherein the zirconium salt is one or more of zirconium nitrate, zirconium oxynitrate, and zirconium oxychloride, and the zirconium concentration is 0.1-1 mol / L, and heat to 70-90°C for 30 minutes; Prepare a rare earth salt solution, wherein the rare earth salt is one or more of yttrium nitrate, scandium nitrate, and cerium nitrate, and the concentration of the rare earth salt solution is 0.1-1 mol / L, and heat to 70-90°C for 30 minutes; The zirconium salt aqueous solution and the rare earth salt solution are mixed and heated as follows, and then a precipitant is added: The two solutions were mixed, maintained at the temperature, and continued to heat for 30 minutes, with the mass ratio of rare earth salt measured in rare earth: zirconium salt measured in zirconium = 0.8-0.9; Adding a precipitant under heating and stirring conditions, wherein the precipitant is one or more of ammonia water, sodium hydroxide, and potassium hydroxide; Add dropwise at a uniform rate until the solution pH is > 10, continue stirring for 30 minutes, then stop stirring and heating, and let the slurry stand naturally for 8-12 hours. The volume ratio of the precipitant solution to the salt solution is 0.2-1; After precipitation, the zirconium-based gel powder is obtained by filtering, washing, drying and grinding in the following manner: The slurry was filtered and washed with deionized water, and the washing was stopped when the filtrate reached pH = 7; The obtained gel is dried under ventilation at 110° C. for 4-12 hours to obtain a solid, which is then ground into a powder with a particle size of less than 200 meshes.

3. The method for synthesizing a propane oxidative dehydrogenation catalyst according to claim 1, wherein: The specific steps of mixing the chromium solution with the zirconium-based gel powder to obtain the active substance are as follows: The chromium solution and zirconium-based gel powder are mixed by ball milling; After ball milling and mixing, the mixture is dried, and then ground and calcined to obtain the active substance; The chromium solution and zirconium-based gel powder were ball-milled and mixed as follows; The chromium salt is selected from one or more of chromium nitrate, potassium chromate, ammonium chromate and chromic anhydride; Mix chromium salt and zirconium-based gel powder in a mass ratio of 0.1-0.5, add water in a water-to-material ratio of 0.1-0.5, grind by ball milling and mix until uniform, for at least 15 minutes; The ball-milled mixture is dried, then ground and calcined to obtain the active substance as follows; The ball-milled mixture is dried at 110°C for 4-12 hours through ventilation, and then fully ground to particles with a mesh size of less than 40 mesh; After air roasting, the roasting temperature is 200-400℃ and the time is 2-4 hours; Then grind again to a powder with a mesh size of less than 200 mesh to obtain the active substance.

4. The method for synthesizing a propane oxidative dehydrogenation catalyst according to claim 1, wherein: Mix the metal oxide, silicon source, template, additive and solvent as follows: Grinding the metal oxide particles to a particle size of less than 400 mesh; Adding a silicon source, wherein the silicon source is ethyl orthosilicate or methyl orthosilicate; Adding a template, the template is CTAB or TPOH; Adding an auxiliary agent, which is urea, ammonium bicarbonate or triethanolamine; Adding a solvent, which is a mixed solvent of water and ethanol in a volume ratio of 1:1; The hydrothermal reaction was carried out as follows: After stirring thoroughly at 60-80°C for 10 minutes, the mixture was aged for 4 hours and then subjected to hydrothermal reaction at 120-160°C for 12 hours before cooling. The obtained solid was filtered and washed with deionized water until the pH was less than 7. The hydrothermal reaction product is dried as follows; Dry at 110°C for 4-12 hours; The dried sodium tungstate was impregnated as follows; Prepare a sodium tungstate aqueous solution with a concentration of 0.1 mol / L, then immerse the dried material in the sodium tungstate aqueous solution for 2-3 hours; The modified metal oxide is obtained by drying and grinding after impregnation as follows; The modified metal oxide is dried at 110° C. for 4-12 hours through ventilation, and then ground and sieved to obtain particles with a particle size of less than 400 meshes.

5. The method for synthesizing a propane oxidative dehydrogenation catalyst according to claim 1, wherein: The specific steps of mixing the active material, modified metal oxide, and inert carrier, and then drying, calcining, and reducing to obtain the propane oxidative dehydrogenation catalyst are as follows: The active material, modified metal oxide, inert carrier and binder are fully mixed; After being fully mixed, the mixture is rolled using a roller compactor and then extruded into a mold; Then drying and sieving; Then, the catalyst is subjected to primary calcination, secondary calcination and reduction to obtain the propane oxidative dehydrogenation catalyst.

6. The method for synthesizing a propane oxidative dehydrogenation catalyst according to claim 5, wherein: The active material, modified metal oxide, inert carrier and binder are thoroughly mixed as follows; The active substance and the modified metal oxide are fully mixed, and an inert carrier is added as an auxiliary carrier; Adding an inorganic binder, wherein the inorganic binder is a silica sol solution, an aluminum sol solution, or a silica-alumina sol solution; adding a pore-forming agent, wherein the pore-forming agent is sesbania powder, guar gum powder or starch; Mixing should be done with a plow mixer for at least 15 minutes; After being fully mixed in the following manner, the mixture is rolled using a roller compactor, and then extruded into a mold; The catalyst is rolled with a roller compactor at a pressure of not less than 2 MPa for at least 10 minutes and extruded with a screw extruder to form a strip or clover-shaped catalyst with a diameter of X and a length of Y, where X is 1.5-9 mm and 2X <Y<10X; Drying and sieving are carried out as follows; Air dry at 110°C for 4-12 hours, then remove the fine powder and small particles by sieving, the sieve used for sieving is 20 mesh; The propane oxidative dehydrogenation catalyst is obtained by performing primary calcination, secondary calcination, and reduction as follows; Calcination in air at 400-600℃ for 1-4 hours, and secondary calcination at 600-800℃ for 2-6 hours; The reducing atmosphere is H2 / N2 with a volume ratio of 30 / 70, a temperature of 300-500°C, a mass space velocity of 1-4 / hour, and is continued for 2-6 hours, and then cooled to room temperature to obtain a propane oxidative dehydrogenation catalyst.

7. Use of the propane oxidative dehydrogenation catalyst prepared according to the synthesis method of the propane oxidative dehydrogenation catalyst according to any one of claims 1 to 6 in the propane oxidative dehydrogenation.

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