Catalyst for dehydrogenation of low bulk density alkylaromatics and method of making and using same

Abstract

The present application provides a catalyst for low bulk density alkyl aromatic dehydrogenation, which comprises the following components by weight percentage: 61-82% of Fe2O3; 8-13% of alkali metal oxide; 7-14% of CeO2; 0.1-6% of VIB group metal oxide; 0.1-5% of alkaline earth metal oxide; 0.05-4% of IIIB group metal oxide except Ce; and 0.001-3% of IIB group metal oxide. The present application adopts pyrolysis high weight loss metal salt and template agent method, and the IIIB group metal oxide except Ce and the IIB group metal oxide synergistically act on each other; the catalyst is prepared through sufficient mixing, extrusion, molding, drying, calcination and the like, and has a median pore size of 250-400 nm, thereby solving the problems of high bulk density or low bulk density and poor crushing strength; and the catalyst has high activity and selectivity under low water ratio conditions, and can be used in the industrial production of alkyl aromatic under low water ratio conditions.

Description

Technical Field

[0001] This invention relates to the field of catalyst preparation technology, specifically to a catalyst for the dehydrogenation of low bulk density alkyl aromatics, its preparation method, and its application. Background Technology

[0002] Styrene is an important organic chemical raw material, mainly produced industrially by the dehydrogenation of ethylbenzene. The main reaction is C6H5-C2H5→C6H5CH=CH2+H2ΔH f298 = +123 kJ / mol. This reaction is an endothermic reaction with increasing volume. The vapor is easily separated from the reactants and products, playing an important role in the reaction process.

[0003] (1) Provide heat to the reaction mixture;

[0004] (2) Reduce the partial pressure of the product and balance the temperature and conversion rate;

[0005] (3) Remove coke through water-gas shift reaction;

[0006] (4) Minimize ethylbenzene cracking;

[0007] (5) Maintain the oxidized state of the Fe catalyst to prevent it from being reduced by H2;

[0008] (6) Inducing K redistribution on the catalyst during the reaction improves the catalytic lifetime.

[0009] The activation of the catalyst precursor to produce a metastable potassium ferrite phase, the high-temperature cracking of water, and the vaporization of carbon determine that this reaction is usually carried out at temperatures above 600°C. Most existing styrene catalysts are iron-potassium based, with iron oxide as the main catalyst and potassium as the main promoter, and also contain structural stabilizers such as oxides of Ce, Mg, Mo, W, or Ca. In recent years, market demands for high-load operation, energy conservation and emission reduction, and larger-scale plants have urged catalysts to be continuously improved towards higher yields, tolerance to low water ratios, high stability, low bulk density, and high strength.

[0010] The intrinsic activity of the ethylbenzene dehydrogenation reaction is relatively high under the reaction conditions. The actual reaction rate is influenced by intraparticle diffusion, making it an internal diffusion-controlled reaction. Reducing the catalyst size is beneficial for improving catalytic activity, but it also increases the bed pressure drop. Increasing the macropore size reduces internal diffusion resistance, which helps to reduce side reactions and improve selectivity. The specific surface area of ​​existing catalysts is typically between 1 and 10 m². 2The bulk density is typically between 1.30 and 1.70 kg / L. Higher bulk density does not necessarily improve catalyst strength and performance, but it does increase material consumption during catalyst production. Pore formation is a key aspect of preparing porous inorganic materials. The pore formation method directly affects the pore structure and porosity of the material. CN101182235A describes several pore formation methods, including: pore-forming agent method, foaming method, sol-gel method, partial sintering method, reaction sintering method, mechanical pore formation method, surfactant self-assembly method, and template replication method. Among these, the pore-forming agent method is one of the most widely used. This method not only facilitates the preparation of porous materials but also allows for adjustment of the pore structure and porosity by modifying the shape, size, and amount of the pore-forming agent, thus meeting different application requirements. Current technologies for reducing bulk density mainly utilize traditional pore-forming agent methods and methods that modify the catalyst configuration. However, the pore-forming agent method is often affected by the decrease in crushing strength, and the reduction in bulk density is limited. In the existing technology, most catalysts are shaped into cylindrical particles of about 3 mm. By increasing the particle size and changing the catalyst configuration (trilobite, pentlobite, etc.), the bulk density of the catalyst can be reduced to a certain extent, but the catalytic activity is significantly reduced due to the decrease in exposed surface area.

[0011] CN105032448A discloses a hydrocarbon dehydrogenation catalyst based on Fe-alkali metal-Group VIB metal-lanthanide element-alkaline earth metal-Ag. It utilizes unsaturated fatty acids or their salts, polysaccharide-derived acids or their salts, graphite, starch, or cellulose as additives and pore-forming agents in the molding and extrusion process. After calcination, a catalyst with a pore volume of 0.05-0.2 ml / g and a catalyst surface area of ​​0.1-10 m² is obtained. 2 / g catalyst. CN112237922 discloses a Fe-K-Ce-W-Ba-Ti-Er / Tm / Yb ultra-low water ratio ethylbenzene dehydrogenation catalyst and its preparation method, using graphite, polystyrene microspheres, or sodium carboxymethyl cellulose as pore-forming agents; CN112717970 discloses an alkyl aromatic hydrocarbon dehydrogenation method, using a combination of carbon-based and iron-based catalysts for dehydrogenation, wherein the pore-forming agent in the iron-based catalyst is selected from at least one of sodium carboxymethyl cellulose, methyl cellulose, hydroxypropyl cellulose, and guar gum powder. However, none of the above patents mention the packing density of the catalyst after molding.

[0012] Low packing density is achieved by increasing the proportion of compounds containing light elements (such as H, Li, Be, B, C, N, O, Na, Mg, Al, Si, P, S, etc.) or by increasing pore volume through methods such as pore formation, foaming, and sol-gel processes. Since the catalyst precursors for alkyl aromatic hydrocarbon dehydrogenation reaction systems require high-temperature calcination in air for induced formation, and light elements, especially non-metallic elements (H, B, C, N, etc.), exhibit poor thermal stability in high-temperature air, the latter method of increasing porosity is often chosen. However, the improvement in porosity is limited by pore size, uniformity, and the material's inherent strength, resulting in limited advancements with existing technologies. Therefore, increasing the pore size and volume while simultaneously considering pore size uniformity, connectivity, and the material's binding force can more effectively reduce the impact of increased pore volume on material structure and strength, further lowering the packing density. Summary of the Invention

[0013] To address the issue of high catalyst packing density in existing technologies, this invention provides a catalyst for the dehydrogenation of low-bulk-density alkyl aromatics, its preparation method, and its application. The catalyst for the dehydrogenation of low-bulk-density alkyl aromatics of this invention maintains good catalytic activity and yield under reaction conditions, while also exhibiting characteristics such as low bulk density and good strength.

[0014] In a first aspect, the present invention provides a composition for preparing a catalyst for the dehydrogenation of low bulk density alkyl aromatics.

[0015] As a specific embodiment of the present invention, the catalyst composition includes a metal source and an additive; the metal source includes an Fe source, an alkali metal source, a Ce source, a Group VIB metal source, an alkaline earth metal source, a Group IIIB metal source other than Ce, and a Group IIB metal source; the additive includes an organic template agent and a surfactant; the amount of the additive added is 0.1% to 6% of the total mass of the catalyst composition based on the oxide content; at least one of the Ce source, the alkali metal source, and the Group IIB metal source includes a high thermal weight loss salt, and the amount of the high thermal weight loss salt added is 1% to 30% of the total mass of the catalyst composition based on the oxide content;

[0016] As a specific embodiment of the present invention, the amount of the group IIB metal source added is 0.001 to 3% of the total amount of the metal source added; the amount of the group IIIB metal source other than Ce added is 0.05 to 4% of the total amount of the metal source added.

[0017] As a specific embodiment of the present invention, the high thermal weight loss salt in the Ce source includes at least one of oxalate, acetate, carbonate, nitrate, and sulfate with a pyrolysis weight loss rate >40wt%; such as: at least one of cerium ammonium sulfate dihydrate (-72.79%), cerium(III) ammonium nitrate tetrahydrate (-69.17%), cerium ammonium nitrate (-68.60%), cerium(III) hexahydrate (-60.36%), cerium sulfate tetrahydrate (-57.43%), cerium oxalate decahydrate (-52.47%), cerium oxalate nonahydrate (-51.26%), cerium sulfate (-48.19%), cerium acetate hydrate (-45.75%), and cerium carbonate octahydrate (-43.04%). The high-heat-weight-loss salts in the alkali metal source include at least one of carbonates, oxalates, nitrates, sulfates, acetates, and citrates with a pyrolysis weight loss rate >50 wt%. Taking potassium salts as an example, the preferred choices are at least one of potassium tetraoxalate dihydrate (-81.47%), potassium bisulfate (-65.41%), potassium persulfate (-65.15%), potassium bioxate (-63.24%), potassium citrate monohydrate (-56.44%), potassium citrate (-53.88%), potassium nitrate (-53.41%), potassium bicarbonate (-52.96%), and potassium acetate (-52.01%) with a pyrolysis weight loss rate >50 wt%. The high-heat-weight-loss salts in the Group IIB metal source include at least one of carbonates, nitrates, acetates, oxalates, and sulfates with a pyrolysis weight loss rate >30 wt%. Specifically, at least one of the following is preferred: zinc nitrate hexahydrate (-72.65%), zinc sulfate heptahydrate (71.7%), zinc acetate dihydrate (-62.93%), cadmium nitrate tetrahydrate (-58.37%), zinc nitrate (57.04%), zinc oxalate dihydrate (-57.04%), zinc acetate (-55.65%), zinc sulfate monohydrate (-54.66%), zinc sulfate (-54.60%), cadmium acetate dihydrate (-51.82%), cadmium sulfate 8 / 3 hydrate (-49.95%), cadmium sulfate (-38.40%), zinc carbonate (-35.11%), and mercuric nitrate monohydrate (-33.27%), with a pyrolysis weight loss rate >30 wt%.

[0018] As a specific embodiment of the present invention, the alkali metal source is selected from at least one of Li, Na, and K metal sources; and / or the group VIB metal source is selected from at least one of Cr, Mo, and W metal sources; and / or the alkaline earth metal source is selected from at least one of Mg, Ca, and Sr metal sources; and / or the group IIIB metal source other than Ce is selected from at least one of Y, La, Nd, Sm, Gd, and Er metal sources; and / or the group IIB metal source is selected from at least one of Zn, Cd, and Hg metal sources.

[0019] As a specific embodiment of the present invention, the Fe source is selected from at least one of iron oxide red, iron oxide yellow, ferric nitrate, ferric citrate, and ferric ammonium citrate; and / or the alkali metal source is selected from at least one of carbonate, oxalate, nitrate, sulfate, acetate, citrate, and hydroxide; and / or the Ce source is selected from at least one of cerium oxide, cerium oxalate, cerium acetate, cerium carbonate, cerium hydroxide, cerium nitrate, cerium sulfate, and cerium ammonium sulfate; and / or the VIB metal source is selected from at least one of ammonium salt, metaacid ammonium salt, and metal oxide; and / or the alkaline earth metal source is selected from at least one of oxide, carbonate, and hydroxide; and / or the Group IIIB metal source other than Ce is selected from at least one of metal oxide, hydroxide, carbonate, oxalate, acetate, and nitrate; and / or the Group IIB metal source is selected from at least one of metal oxide, hydroxide, carbonate, nitrate, acetate, oxalate, and sulfate.

[0020] As a specific embodiment of the present invention, the organic template agent comprises at least one of the following: polymethyl methacrylate (PMMA), polyvinyl alcohol (PVA), polydivinylbenzene, polystyrene-divinylbenzene, polyvinyl alcohol, polyvinyl acetate, polyvinyl acetate, polyquaternium salt, polyethyleneimine, polyurethane, poly(pyrrole), poly(aniline), poly(bithiophene), nonionic cellulose ethers (such as methyl, ethyl, hydroxyethyl, hydroxypropyl methyl, carboxymethyl, etc.), ionic cellulose ethers (such as the above-mentioned nonionic cellulose ether sodium salt, ammonium salt, etc.), sodium polyacrylate (PAAS), starch, povidone, polystyrene microspheres, and cyclodextrin.

[0021] In this invention, the amount of the organic template agent is 0.09 to 5% by weight of the total mass (based on oxides) of the catalyst for dehydrogenation of low bulk density alkyl aromatics, preferably 0.2 to 4% by weight;

[0022] As a specific embodiment of the present invention, the surfactant comprises at least one of the following: hexadecyltrimethylammonium bromide (CTAB), hexadecyltrimethylammonium chloride (CTAC), hexadecylpyridine bromide (CPBr), sodium dodecyl sulfate (LAS), dodecylbenzene sulfonic acid, polyacrylamide, sodium fatty alcohol ether sulfate (AES), sodium ethoxylated fatty acid methyl ester sulfonate (FMES), sodium α-olefin sulfonate (AOS), sodium secondary alkyl sulfonate (SAS), polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer (P123), polyoxyethylene polyoxypropylene ether block copolymer (F127), and fatty alcohol polyoxyethylene ether (AEO, such as hexadecyl alcohol polyoxyethylene ether, lauryl alcohol polyoxyethylene ether (Brij)).

[0023] In this invention, the amount of the surfactant is 0.01 to 1% by weight of the total mass (based on oxides) of the catalyst for dehydrogenation of low bulk density alkyl aromatics, preferably 0.04 to 0.25% by weight;

[0024] All of the above-mentioned raw materials used in this invention can be prepared in-house or purchased commercially; this invention does not impose any particular limitations on them.

[0025] Secondly, the present invention proposes a catalyst for the dehydrogenation of low bulk density alkyl aromatics, wherein the median pore size is preferably in the range of 250 to 400 nm.

[0026] As a specific embodiment of the present invention, a catalyst for dehydrogenation of low bulk density alkyl aromatics comprises the following components by weight percentage: 61-82% Fe₂O₃; 8-13% alkali metal oxides; 7-14% CeO₂; 0.1-6% Group VIB metal oxides; 0.1-5% alkaline earth metal oxides; 0.05-4% Group IIIB metal oxides other than Ce; and 0.001-3% Group IIB metal oxides. Preferably, it comprises the following components by weight percentage: 63-77% Fe₂O₃; 8-12% alkali metal oxides; 7-13% CeO₂; 0.5-5% Group VIB metal oxides; 0.5-4% alkaline earth metal oxides; 0.1-3% of at least one Group IIIB metal oxide other than Ce; 0.1-2% of at least one Group IIB metal oxide; and 0.24-4.25% additives.

[0027] In a specific embodiment of the present invention, the weight ratio of the Group IIIB metal oxide (excluding Ce) to the Group IIB metal oxide is 0.1–60:1, preferably 0.5–2.5:1. The Group IIIB metal oxide (excluding Ce) and the Group IIB metal oxide work synergistically to solve problems such as high packing density or poor crushing strength of catalysts used for the dehydrogenation of low-bulk-density alkyl aromatics, thereby giving the alkyl aromatic dehydrogenation catalyst of the present invention high activity and selectivity.

[0028] In the above technical solutions, VIB metals (Cr, Mo, W) have excellent antioxidant properties, which can help iron oxides maintain structural stability during high-temperature reactions; alkaline earth metals (Mg, Ca, Sr) are often used as structural aids to stabilize Fe. 3+Simultaneously, adjusting surface alkalinity improves selectivity; Group IIIB metal oxides (Y, La, Nd, Sm, Gd, Er) can provide oxygen holes, accelerating electron transfer on the catalyst surface and enhancing catalytic activity. Furthermore, the lattice oxygen in Group IIIB metal oxides can accelerate coke removal, inhibit coke formation, and improve catalyst stability. Group IIB metal oxides, on the other hand, possess excellent corrosion resistance and readily form thermally stable cubic spinel structures with iron oxides.

[0029] The pore structure (pore volume, median pore size, etc.) of the catalyst in this invention was measured using a Thermo Electron Pascal 140 / 240 low / high pressure mercury porosimeter (130° contact angle, mercury surface tension 0.473 N / m). The Pascal 140 low-pressure mercury porosimeter has the following testing range: pressure: 0.1–400 kPa, pore size: 3.8–116 μm; the Pascal 240 high-pressure mercury porosimeter has the following testing range: pressure: 200 MPa, pore size: 0.0074–15 μm. The median pore size is defined as the pore size required to achieve 50% of the mercury porosimeter volume.

[0030] In this invention, the crushing strength of the catalyst was measured according to the test methods and requirements specified in the current national chemical industry standard HG / T 2782-2011, using a DL-II intelligent particle strength tester. For each catalyst sample, 30 5mm long specimens were selected, and the arithmetic mean was taken as the crushing strength, in N / mm.

[0031] Thirdly, the present invention provides a method for preparing a catalyst for dehydrogenation of low bulk density alkyl aromatics, comprising: uniformly mixing Fe source, Ce source, alkali metal source, group VIB metal source, alkaline earth metal source, group IIIB metal source other than Ce, group IIB metal source, etc.; dissolving a surfactant in a solvent such as water or an alcohol and dissolving it by ultrasonication; mixing the powder with the solvent to form a slurry; mixing the slurry with a highly ordered organic template agent; after the solvent gradually vaporizes and the slurry becomes a viscous paste, extruding and granulating it into cylindrical particles with a diameter of 3 mm and a length of 5-10 mm; and finally obtaining the finished catalyst through drying and calcination processes.

[0032] As a specific embodiment of the present invention, the preparation method of the aromatic hydrocarbon dehydrogenation catalyst includes the following steps:

[0033] (1) The Fe source, Ce source, alkali metal source, group VIB metal source, alkaline earth metal source, group IIIB metal source other than Ce, and group IIB metal source are mixed evenly to obtain a first mixed powder; preferably, the rotation speed is 1 to 50 r / min and the time is 10 to 300 min, preferably using a mixer such as a mixing mill, ball mill or plow mill.

[0034] (2) Dissolve the surfactant in a solvent, preferably by ultrasonic dissolution, preferably by ultrasonic frequency of 20 to 120 kHz and ultrasonic time of 5 to 60 min; obtain a surfactant solution, and then mix the surfactant solution with the first mixed powder to obtain a second mixed slurry.

[0035] (3) The second mixed slurry is mixed with the organic template agent for a third time to remove the solvent and obtain a third mixed paste; preferably, the solvent is removed by heating or negative pressure.

[0036] (4) Dry and calcine the third mixed paste.

[0037] As a specific embodiment of the present invention, the drying conditions for the third mixed paste are: temperature of 25–200°C and time of 6–24 hours. Preferably, the drying conditions are: drying at 30–80°C for 4–16 hours.

[0038] As a specific embodiment of the present invention, the calcination conditions are: a temperature of 250-1200℃ and a time of 4-20 hours. Preferably, the calcination conditions are: calcination at 300-650℃ for 2-12 hours, followed by heating to 750-1100℃ and calcination for 2-8 hours.

[0039] As a specific embodiment of the present invention, the solvent is at least one selected from water, alcohol (methanol, ethanol, ethylene glycol), organic amine (such as dimethylformamide (DMF)), ammonia, and dimethyl sulfoxide (DMSO); and / or the amount of solvent added is 10-80% by weight (calculated as oxides) of the total mass of the catalyst used for low bulk density alkyl aromatic hydrocarbon dehydrogenation. The amounts of the Fe source, alkali metal source, Ce source, Group VIB metal source, alkaline earth metal source, Group IIIB and Group IIB metal sources added are all calculated as oxides.

[0040] Fourthly, the present invention provides the application of the catalyst for the dehydrogenation of low bulk density alkyl aromatics in the dehydrogenation reaction of alkyl aromatics; preferably, its application in the dehydrogenation reaction of low bulk density alkyl aromatics. It is particularly suitable for the industrial production of alkenyl aromatics under low water ratio conditions.

[0041] Fifthly, the present invention provides a method for the dehydrogenation of alkyl aromatics to produce alkenyl aromatics, comprising: reacting alkyl aromatics, water vapor, and the above-mentioned catalyst for the dehydrogenation of low bulk density alkyl aromatics under alkyl aromatics dehydrogenation reaction conditions.

[0042] As a specific embodiment of the present invention, the dehydrogenation reaction conditions of the alkyl aromatic hydrocarbon include: a temperature of 580–650°C, more preferably 590–630°C; and a volume hourly space velocity of 0.5–1.5 h⁻¹. -1 More preferably 0.8 to 1.5 h -1The weight ratio of water to alkyl aromatics is 0.5–1.3, preferably 0.9–1.3; the pressure is 20 kPaA to 0.1 MPaA, more preferably 40 kPaA to 80 kPaA. The reactants flowing out of the reactor are condensed in water and their composition is analyzed by gas chromatography.

[0043] Ethylbenzene conversion and styrene selectivity are calculated using the following formulas:

[0044]

[0045]

[0046] The catalyst prepared by the above method was evaluated for its performance in the dehydrogenation reaction of alkyl aromatics in an isothermal fixed bed. The process is briefly described below:

[0047] The reactor is a stainless steel tube with an inner diameter of 1”, filled with 50-150 ml of cylindrical catalyst with a diameter of 3 mm. Deionized water and ethylbenzene are separately fed into a preheating mixer via metering pumps, preheated and mixed into a gaseous state before entering the reactor. The reactor is heated by an electric heating wire to reach a predetermined temperature.

[0048] Compared with existing technologies, this invention combines a high-pyrolysis-weight-loss metal salt with a template agent method. A certain proportion of high-pyrolysis-weight-loss metal salts are added to the Fe-Ce-alkali metal (Li, Na, K)-Group VIB (Cr, Mo, W)-alkaline earth (Mg, Ca, Sr)-Group IIIB (Y, La, Nd, Sm, Gd, Er)-Group IIB (Zn, Cd, Hg) metal system to increase the pore volume of the catalyst. Simultaneously, a template agent method is used, adding a certain amount of organic template agent and surfactant to further increase the pore volume while enhancing the interaction between the catalyst raw material components. Furthermore, the synergistic effect of Group IIIB metal oxides (excluding Ce) and the Group IIB metal oxides results in a high-activity and selectivity alkyl aromatic hydrocarbon dehydrogenation catalyst. After thorough mixing, extrusion, molding, drying, and calcination, this invention yields a catalyst with a median pore size of 250–400 nm for the dehydrogenation of low-bulk-density alkyl aromatic hydrocarbons, solving the problem of high bulk density or poor crushing strength in low-bulk-density catalysts. The catalyst of the present invention for the dehydrogenation of low bulk density alkyl aromatics exhibits high activity and selectivity under low water ratio conditions and can be used in the industrial production of alkenyl aromatics under low water ratio conditions. The prepared catalyst has low bulk density and good strength, and maintains high catalytic performance under reaction conditions, making it suitable for the industrial production of alkyl aromatics dehydrogenation. Detailed Implementation

[0049] The present invention will be further described below with reference to specific embodiments, but this does not constitute any limitation on the present invention.

[0050] The raw materials used in all embodiments of the present invention can be either self-made or commercially available.

[0051] Example 1

[0052] A method for preparing a catalyst for the dehydrogenation of low bulk density alkyl aromatics includes the following steps:

[0053] (1) Using a mixing mill, the following components were mixed: iron oxide red (equivalent to 44.51 parts Fe2O3), iron oxide yellow (equivalent to 22.25 parts Fe2O3), cerium nitrate hexahydrate (equivalent to 12.85 parts CeO2), potassium tetraoxalate dihydrate (equivalent to 7.77 parts K2O), sodium citrate (equivalent to 0.37 parts Na2O), ammonium molybdate (equivalent to 1.83 parts MoO3), ammonium tungstate (equivalent to 1.70 parts WO3), and MgO (equivalent to 2.61 parts MgO). 1.31 parts of calcium hydroxide (CaO), 0.48 parts of Y₂O₃, 0.48 parts of La₂O₃, 0.48 parts of Nd₂O₃, 0.48 parts of Sm₂O₃, 0.48 parts of Gd₂O₃, 0.48 parts of Er₂O₃, zinc nitrate hexahydrate (equivalent to 0.96 parts of ZnO), and cadmium nitrate tetrahydrate (equivalent to 0.96 parts of CdO) were mixed evenly at a speed of 48.5 r / min for 50 min to obtain the first mixed powder. The high-heat weight loss salts of Ce, alkali metals, and Group IIB metal salts accounted for 22.91% of the total catalyst mass, based on oxide content.

[0054] (2) Keeping the rotation speed constant, the first mixed slurry is mixed with 2.26% (wt) of organic template agent polystyrene to obtain the second mixed powder.

[0055] (3) Dissolve 0.1% (wt) of surfactant polyacrylamide, equivalent to the total catalyst mass, in 18.7% (wt) of solvent water, and sonicate at a frequency of 30 kHz for 40 min. Mix the dissolved solution with the second mixed powder to obtain a third mixed paste. Extrude the paste using a kneader, cut it into pellets with a diameter of 3 mm and a length of 5-10 mm, place them in an oven, bake at 45℃ for 8 hours, bake at 150℃ for 4 hours, and then place them in a muffle furnace for calcination at 400℃ for 6 hours and 900℃ for 4 hours to obtain the finished catalyst. The catalyst composition is listed in Table 1.

[0056] The median pore size was measured to be 343.5 nm using a mercury porosimeter, the tap density was measured to be 128.5 g / 100 ml using a tap density meter, and the crushing strength was measured to be 165.7 N / 5 mm using a DL-II intelligent particle strength meter. Simultaneously, 100 ml of catalyst was added to the reactor and incubated at atmospheric pressure and a liquid hourly space velocity (LHSV) of 1.0 h⁻¹. －1The performance was evaluated at a temperature of 630℃ and a water ratio of 1.15 (wt). The results of physical property tests and steady-state performance are listed in Table 3.

[0057] Example 2

[0058] A method for preparing a catalyst for the dehydrogenation of low bulk density alkyl aromatics includes the following steps:

[0059] (1) A mixing mill was used to uniformly mix the following components: iron oxide red (equivalent to 51.28 parts Fe2O3), iron oxide yellow (equivalent to 25.64 parts Fe2O3), cerium hydroxide (equivalent to 9.45 parts CeO2), lithium hydroxide (equivalent to 0.64 parts Li2O), sodium hydroxide (equivalent to 0.73 parts Na2O), potassium hydroxide (equivalent to 4.60 parts K2O), potassium citrate monohydrate (equivalent to 3.67 parts K2O), ammonium molybdate (equivalent to 0.53 parts MoO3), 0.64 parts CaO, 1.0 part Nd2O3, 1.0 part Er2O3, and 0.82 parts CdO. The mixing speed was 37.1 r / min, and the mixing time was 250 min to obtain the first mixed powder. Among them, the high thermal weight loss salts of Ce, alkali metals, and Group IIB metal salts accounted for 3.67% of the total catalyst mass, based on oxide content.

[0060] (2) Keeping the rotation speed constant, the first mixed slurry is mixed with 3.90% (wt) of organic template agent polystyrene to obtain the second mixed powder.

[0061] (3) Dissolve 0.1% (wt) of surfactant polyacrylamide, equivalent to the total catalyst mass, in 35.8% (wt) of solvent water, and sonicate at a frequency of 110 kHz for 10 min. Mix the dissolved solution with the second mixed powder to obtain a third mixed paste. Extrude the paste using a kneader, cut it into pellets with a diameter of 3 mm and a length of 5-10 mm, place them in an oven, bake at 45℃ for 8 hours, bake at 150℃ for 4 hours, and then place them in a muffle furnace for calcination at 400℃ for 6 hours and 900℃ for 4 hours to obtain the finished catalyst. The catalyst composition is listed in Table 1.

[0062] The median pore size was measured to be 320.7 nm using a mercury porosimeter, the tap density was measured to be 133.7 g / 100 ml using a tap density meter, and the crushing strength was measured to be 173.9 N / 5 mm using a DL-II intelligent particle strength meter. Simultaneously, 100 ml of catalyst was added to the reactor and incubated at atmospheric pressure and a liquid hourly space velocity (LHSV) of 1.0 h⁻¹. －1 The performance was evaluated at a temperature of 630℃ and a water ratio of 1.15 (wt). The results of physical property tests and steady-state performance are listed in Table 3.

[0063] Example 3

[0064] A method for preparing a catalyst for the dehydrogenation of low bulk density alkyl aromatics includes the following steps:

[0065] (1) Using a mixing mill, the following components were mixed uniformly: iron oxide red (equivalent to 47.93 parts Fe2O3), iron oxide yellow (equivalent to 23.97 parts Fe2O3), cerium ammonium nitrate (equivalent to 3.06 parts CeO2), cerium hydroxide (equivalent to 4.80 parts CeO2), potassium nitrate (equivalent to 11.88 parts K2O), ammonium chromate (equivalent to 0.79 parts Cr2O3), 2.38 parts MoO3, 1.62 parts WO3, 2.80 parts SrO, 0.24 parts Y2O3, 0.24 parts Sm2O3, and 0.29 parts HgO. The mixing speed was 32.7 r / min, and the mixing time was 150 min to obtain the first mixed powder. Among them, the high thermal weight loss salts of Ce, alkali metals, and Group IIB metal salts accounted for 14.94% of the total catalyst mass, based on oxide content.

[0066] (2) Keeping the rotation speed constant, the first mixed slurry is mixed with 0.31% (wt) of organic template agent polystyrene, which is equivalent to the total catalyst mass, to obtain the second mixed powder.

[0067] (3) Dissolve 0.1% (wt) of surfactant polyacrylamide, equivalent to the total catalyst mass, in 57.5% (wt) of solvent water, and sonicate at a frequency of 60 kHz for 25 min. Mix the dissolved solution with the second mixed powder to obtain a third mixed paste. Extrude the paste using a kneader, cut it into pellets with a diameter of 3 mm and a length of 5-10 mm, place them in an oven, bake at 45℃ for 8 hours, bake at 150℃ for 4 hours, and then place them in a muffle furnace for calcination at 400℃ for 6 hours and 900℃ for 4 hours to obtain the finished catalyst. The catalyst composition is listed in Table 1.

[0068] The median pore size was measured to be 275.8 nm using a mercury porosimeter, the tap density was measured to be 142.6 g / 100 ml using a tap density meter, and the crushing strength was measured to be 186.1 N / 5 mm using a DL-II intelligent particle strength meter. Simultaneously, 100 ml of catalyst was added to the reactor and incubated at atmospheric pressure and a liquid hourly space velocity (LHSV) of 1.0 h⁻¹. －1 The performance was evaluated at a temperature of 630℃ and a water ratio of 1.15 (wt). The results of physical property tests and steady-state performance are listed in Table 3.

[0069] Example 4

[0070] A method for preparing a catalyst for the dehydrogenation of low bulk density alkyl aromatics includes the following steps:

[0071] (1) Using a mixing mill, the following components were mixed: iron oxide red (equivalent to 41.876 parts Fe2O3), iron oxide yellow (equivalent to 20.94 parts Fe2O3), cerium oxalate nonahydrate (equivalent to 13.32 parts CeO2), potassium hydrogen oxalate (equivalent to 10.22 parts K2O), sodium nitrate (equivalent to 1.28 parts Na2O), lithium nitrate (equivalent to 0.61 parts Li2O), 0.47 parts Cr2O3, 1.57 parts MoO3, 1.93 parts WO3, and the equivalent... 1.59 parts of magnesium hydroxide (MgO), 1.82 parts of SrO, 0.81 parts of Sm₂O₃, 0.81 parts of Gd₂O₃, 0.81 parts of Er₂O₃, zinc nitrate hexahydrate (equivalent to 0.648 parts of ZnO), cadmium nitrate tetrahydrate (equivalent to 0.648 parts of CdO), and mercuric nitrate monohydrate (equivalent to 0.648 parts of HgO) were mixed evenly at a speed of 22.3 r / min for 100 min to obtain the first mixed powder. The high-heat weight loss salts of Ce, alkali metals, and Group IIB metal salts accounted for 27.374% of the total catalyst mass, based on oxide content.

[0072] (2) Keeping the rotation speed constant, the first mixed slurry is mixed with 1.91% (wt) of organic template agent polystyrene, to obtain the second mixed powder.

[0073] (3) Dissolve 0.1% (wt) of surfactant polyacrylamide, equivalent to the total catalyst mass, in 23.6% (wt) of solvent water, and sonicate at a frequency of 40 kHz for 30 min. Mix the dissolved solution with the second mixed powder to obtain a third mixed paste. Extrude the paste using a kneader, cut it into pellets with a diameter of 3 mm and a length of 5-10 mm, place them in an oven, bake at 45℃ for 8 hours, bake at 150℃ for 4 hours, and then place them in a muffle furnace for calcination at 400℃ for 6 hours and 900℃ for 4 hours to obtain the finished catalyst. The catalyst composition is listed in Table 1.

[0074] The median pore size was measured to be 351.4 nm using a mercury porosimeter, the tap density was measured to be 127.2 g / 100 ml using a tap density meter, and the crushing strength was measured to be 149.9 N / 5 mm using a DL-II intelligent particle strength meter. Simultaneously, 100 ml of catalyst was added to the reactor and incubated at atmospheric pressure and a liquid hourly space velocity (LHSV) of 1.0 h⁻¹. －1 The performance was evaluated at a temperature of 630℃ and a water ratio of 1.15 (wt). The results of physical property tests and steady-state performance are listed in Table 3.

[0075] Example 5

[0076] A method for preparing a catalyst for the dehydrogenation of low bulk density alkyl aromatics includes the following steps:

[0077] (1) Using a mixing mill, the following components were mixed evenly: iron oxide red (equivalent to 43.912 parts Fe2O3), iron oxide yellow (equivalent to 21.95 parts Fe2O3), cerium oxalate decahydrate (equivalent to 8.23 ​​parts CeO2), cerium hydroxide (equivalent to 4.22 parts CeO2), potassium hydroxide (equivalent to 8.14 parts K2O), 2.81 parts Cr2O3, 1.12 parts WO3, magnesium hydroxide (equivalent to 0.91 parts MgO), calcium hydroxide (equivalent to 2.38 parts CaO), 1.63 parts SrO, 0.73 parts Y2O3, 0.73 parts La2O3, 0.73 parts Nd2O3, 0.836 parts ZnO, 0.836 parts CdO, and 0.836 parts HgO. The mixing speed was 39.5 r / min and the time was 300 min to obtain the first mixed powder. Based on oxide content, the high thermal weight loss salts among Ce, alkali metals, and Group IIB metal salts account for 8.23% of the total catalyst mass.

[0078] (2) Keeping the rotation speed constant, the first mixed slurry is mixed with 1.12% (wt) of organic template agent polystyrene to obtain the second mixed powder.

[0079] (3) Dissolve 0.1% (wt) of surfactant polyacrylamide, equivalent to the total catalyst mass, in 41.8% (wt) of solvent water, and sonicate at a frequency of 80 kHz for 55 min. Mix the dissolved solution with the second mixed powder to obtain a third mixed paste. Extrude the paste using a kneader, cut it into pellets with a diameter of 3 mm and a length of 5-10 mm, place them in an oven, bake at 45℃ for 8 hours, bake at 150℃ for 4 hours, and then place them in a muffle furnace for calcination at 400℃ for 6 hours and 900℃ for 4 hours to obtain the finished catalyst. The catalyst composition is listed in Table 1.

[0080] The median pore size was measured to be 270.1 nm using a mercury porosimeter, the tap density was measured to be 144.1 g / 100 ml using a tap density meter, and the crushing strength was measured to be 193.4 N / 5 mm using a DL-II intelligent particle strength meter. Simultaneously, 100 ml of catalyst was added to the reactor and incubated at atmospheric pressure and a liquid hourly space velocity (LHSV) of 1.0 h⁻¹. －1 The performance was evaluated at a temperature of 630℃ and a water ratio of 1.15 (wt). The results of physical property tests and steady-state performance are listed in Table 3.

[0081] Example 6

[0082] A method for preparing a catalyst for the dehydrogenation of low bulk density alkyl aromatics includes the following steps:

[0083] (1) Using a mixing mill, the following components were mixed evenly: iron oxide red (equivalent to 44.577 parts Fe2O3), iron oxide yellow (equivalent to 22.28 parts Fe2O3), cerium nitrate hexahydrate (equivalent to 12.20 parts CeO2), lithium hydroxide (equivalent to 1.73 parts Li2O), sodium hydroxide (equivalent to 0.91 parts Na2O), potassium hydroxide (equivalent to 1.87 parts K2O), potassium tetraoxalate dihydrate (equivalent to 5.72 parts K2O), 1.48 parts Cr2O3, 1.85 parts MoO3, calcium carbonate (equivalent to 2.07 parts CaO), 1.74 parts SrO, 0.54 parts La2O3, 0.54 parts Gd2O3, 0.831 parts ZnO, 0.831 parts CdO, and 0.831 parts HgO. The mixing speed was 47.6 r / min and the time was 70 min to obtain the first mixed powder. Based on oxide content, the high thermal weight loss salts among Ce, alkali metals, and Group IIB metal salts account for 17.92% of the total catalyst mass.

[0084] (2) Keeping the rotation speed constant, the first mixed slurry is mixed with 0.18% (wt) of organic template agent polystyrene, which is equivalent to the total catalyst mass, to obtain the second mixed powder.

[0085] (3) Dissolve 0.01% (wt) of surfactant polyacrylamide, equivalent to the total catalyst mass, in 76.4% (wt) of solvent water, and sonicate at a frequency of 20 kHz for 15 min. Mix the dissolved solution with the second mixed powder to obtain a third mixed paste. Extrude the paste using a kneader, cut it into pellets with a diameter of 3 mm and a length of 5-10 mm, place them in an oven, bake at 45℃ for 8 hours, bake at 150℃ for 4 hours, and then place them in a muffle furnace for calcination at 400℃ for 6 hours and 900℃ for 4 hours to obtain the finished catalyst. The catalyst composition is listed in Table 1.

[0086] The median pore size was measured to be 289.3 nm using a mercury porosimeter, the tap density was measured to be 141.3 g / 100 ml using a tap density meter, and the crushing strength was measured to be 187.9 N / 5 mm using a DL-II intelligent particle strength meter. Simultaneously, 100 ml of catalyst was added to the reactor and incubated at atmospheric pressure and a liquid hourly space velocity (LHSV) of 1.0 h⁻¹. －1 The performance was evaluated at a temperature of 630℃ and a water ratio of 1.15 (wt). The results of physical property tests and steady-state performance are listed in Table 3.

[0087] Example 7

[0088] A method for preparing a catalyst for the dehydrogenation of low bulk density alkyl aromatics includes the following steps:

[0089] (1) Using a mixing mill, the following components were mixed uniformly: iron oxide red (equivalent to 45.81 parts Fe2O3), iron oxide yellow (equivalent to 22.91 parts Fe2O3), cerium ammonium nitrate (equivalent to 11.89 parts CeO2), lithium hydroxide (equivalent to 1.31 parts Li2O), potassium citrate monohydrate (equivalent to 9.19 parts K2O), 0.59 parts WO3, magnesium carbonate (equivalent to 2.50 parts MgO), 1.0 part La2O3, 1.0 part Nd2O3, 1.0 part Sm2O3, 1.0 part Gd2O3, 0.9 parts ZnO, and 0.9 parts HgO. The mixing speed was 29.3 r / min, and the mixing time was 90 min to obtain the first mixed powder. Among them, the high thermal weight loss salts of Ce, alkali metals, and Group IIB metal salts accounted for 21.08% of the total catalyst mass, based on oxide content.

[0090] (2) Keeping the rotation speed constant, the first mixed slurry is mixed with 4.03% (wt) of organic template agent polystyrene to obtain the second mixed powder.

[0091] (3) Dissolve 0.1% (wt) of surfactant polyacrylamide, equivalent to the total catalyst mass, in 49.9% (wt) of solvent water, and sonicate at a frequency of 120 kHz for 25 min. Mix the dissolved solution with the second mixed powder to obtain a third mixed paste. Extrude the paste using a kneader, cut it into pellets with a diameter of 3 mm and a length of 5-10 mm, place them in an oven, bake at 45℃ for 8 hours, bake at 150℃ for 4 hours, and then calcine them in a muffle furnace at 400℃ for 6 hours and 900℃ for 4 hours to obtain the finished catalyst. The catalyst composition is listed in Table 1.

[0092] The median pore size was measured to be 382.1 nm using a mercury porosimeter, the tap density was measured to be 122.0 g / 100 ml using a tap density meter, and the crushing strength was measured to be 158.5 N / 5 mm using a DL-II intelligent particle strength meter. Simultaneously, 100 ml of catalyst was added to the reactor and incubated at atmospheric pressure and a liquid hourly space velocity (LHSV) of 1.0 h⁻¹. －1 The performance was evaluated at a temperature of 630℃ and a water ratio of 1.15 (wt). The results of physical property tests and steady-state performance are listed in Table 3.

[0093] Example 8

[0094] A method for preparing a catalyst for the dehydrogenation of low bulk density alkyl aromatics includes the following steps:

[0095] (1) Using a mixing mill, the following components were mixed evenly: iron oxide red (equivalent to 46.71 parts Fe2O3), iron oxide yellow (equivalent to 23.35 parts Fe2O3), cerium oxalate nonahydrate (equivalent to 9.92 parts CeO2), sodium hydroxide (equivalent to 1.89 parts Na2O), potassium hydroxide (equivalent to 3.54 parts K2O), potassium nitrate (equivalent to 3.74 parts K2O), 2.21 parts Cr2O3, 1.84 parts MoO3, 1.53 parts WO3, 1.12 parts CaO, 0.48 parts Y2O3, 0.48 parts La2O3, 0.48 parts Nd2O3, 0.48 parts Gd2O3, 0.48 parts Er2O3, 0.875 parts CdO, and 0.875 parts HgO. The mixing speed was 26.8 r / min and the time was 120 min to obtain the first mixed powder. Based on oxide content, the high thermal weight loss salts among Ce, alkali metals, and Group IIB metal salts account for 13.66% of the total catalyst mass.

[0096] (2) Keeping the rotation speed constant, the first mixed slurry is mixed with 2.36% (wt) of organic template agent polystyrene to obtain the second mixed powder.

[0097] (3) Dissolve 0.1% (wt) of surfactant polyacrylamide, equivalent to the total catalyst mass, in 13.8% (wt) of solvent water, and sonicate at a frequency of 100 kHz for 35 min. Mix the dissolved solution with the second mixed powder to obtain a third mixed paste. Extrude the paste using a kneader, cut it into pellets with a diameter of 3 mm and a length of 5-10 mm, place them in an oven, bake at 45℃ for 8 hours, bake at 150℃ for 4 hours, and then place them in a muffle furnace for calcination at 400℃ for 6 hours and 900℃ for 4 hours to obtain the finished catalyst. The catalyst composition is listed in Table 1.

[0098] The median pore size was measured to be 314.6 nm using a mercury porosimeter, the tap density was measured to be 134.5 g / 100 ml using a tap density meter, and the crushing strength was measured to be 181.2 N / 5 mm using a DL-II intelligent particle strength meter. Simultaneously, 100 ml of catalyst was added to the reactor and incubated at atmospheric pressure and a liquid hourly space velocity (LHSV) of 1.0 h⁻¹. －1 The performance was evaluated at a temperature of 630℃ and a water ratio of 1.15 (wt). The results of physical property tests and steady-state performance are listed in Table 3.

[0099] Example 9

[0100] A method for preparing a catalyst for the dehydrogenation of low bulk density alkyl aromatics includes the following steps:

[0101] (1) Using a mixing mill, the following components were mixed uniformly: iron oxide red (equivalent to 47.41 parts Fe2O3), iron oxide yellow (equivalent to 23.71 parts Fe2O3), cerium hydroxide (equivalent to 11.16 parts CeO2), lithium hydroxide (equivalent to 1.03 parts Li2O), potassium hydroxide (equivalent to 10.56 parts K2O), 1.11 parts MoO3, 0.41 parts WO3, magnesium hydroxide (equivalent to 2.36 parts MgO), 0.41 parts Er2O3, zinc oxalate dihydrate (equivalent to 1.250 parts ZnO), and 0.586 parts CdO. The mixing speed was 34.2 r / min, and the mixing time was 210 min to obtain the first mixed powder. The high-heat weight loss salts of Ce, alkali metals, and Group IIB metals accounted for 1.25% of the total catalyst mass, based on oxide content.

[0102] (2) Keeping the rotation speed constant, the first mixed slurry is mixed with 4.70% (wt) of organic template agent polystyrene to obtain the second mixed powder.

[0103] (3) Dissolve 0.1% (wt) of surfactant polyacrylamide, equivalent to the total catalyst mass, in 56.4% (wt) of solvent water, and sonicate at a frequency of 70 kHz for 45 min. Mix the dissolved solution with the second mixed powder to obtain a third mixed paste. Extrude the paste using a kneader, cut it into pellets with a diameter of 3 mm and a length of 5-10 mm, place them in an oven, bake at 45℃ for 8 hours, bake at 150℃ for 4 hours, and then place them in a muffle furnace for calcination at 400℃ for 6 hours and 900℃ for 4 hours to obtain the finished catalyst. The catalyst composition is listed in Table 1.

[0104] The median pore size was measured to be 337.2 nm using a mercury porosimeter, the tap density was measured to be 131.9 g / 100 ml using a tap density meter, and the crushing strength was measured to be 150.5 N / 5 mm using a DL-II intelligent particle strength meter. Simultaneously, 100 ml of catalyst was added to the reactor and incubated at atmospheric pressure and a liquid hourly space velocity (LHSV) of 1.0 h⁻¹. －1 The performance was evaluated at a temperature of 630℃ and a water ratio of 1.15 (wt). The results of physical property tests and steady-state performance are listed in Table 3.

[0105] Example 10

[0106] A method for preparing a catalyst for the dehydrogenation of low bulk density alkyl aromatics includes the following steps:

[0107] (1) A mixing mill was used to uniformly mix the following components: iron oxide red (equivalent to 52.53 parts Fe2O3), iron oxide yellow (equivalent to 26.269 parts Fe2O3), cerium hydroxide (equivalent to 1.70 parts CeO2), cerium oxalate decahydrate (equivalent to 5.98 parts CeO2), lithium hydroxide (equivalent to 0.80 parts Li2O), sodium hydroxide (equivalent to 0.48 parts Na2O), potassium hydroxide (equivalent to 7.02 parts K2O), 0.58 parts Cr2O3, 0.49 parts MgO, calcium hydroxide (equivalent to 1.37 parts CaO), 2.72 parts SrO, 0.06 parts La2O3, and zinc acetate (equivalent to 0.001 parts ZnO). The mixing speed was 42.0 r / min, and the mixing time was 180 min to obtain the first mixed powder. The high-heat weight loss salts of Ce, alkali metals, and Group IIB metal salts accounted for 5.98% of the total catalyst mass, based on oxide content.

[0108] (2) Keeping the rotation speed constant, the first mixed slurry is mixed with 3.08% (wt) of organic template agent polystyrene, which is equivalent to the total catalyst mass, to obtain the second mixed powder.

[0109] (3) Dissolve 0.1% (wt) of surfactant polyacrylamide, equivalent to the total catalyst mass, in 32.6% (wt) of solvent water, and sonicate at a frequency of 50 kHz for 50 min. Mix the dissolved solution with the second mixed powder to obtain a third mixed paste. Extrude the paste using a kneader, cut it into pellets with a diameter of 3 mm and a length of 5-10 mm, place them in an oven, bake at 45℃ for 8 hours, bake at 150℃ for 4 hours, and then place them in a muffle furnace for calcination at 400℃ for 6 hours and 900℃ for 4 hours to obtain the finished catalyst. The catalyst composition is listed in Table 1.

[0110] The median pore size was measured to be 316.1 nm using a mercury porosimeter, the tap density was measured to be 136.4 g / 100 ml using a tap density meter, and the crushing strength was measured to be 178.3 N / 5 mm using a DL-II intelligent particle strength meter. Simultaneously, 100 ml of catalyst was added to the reactor and incubated at atmospheric pressure and a liquid hourly space velocity (LHSV) of 1.0 h⁻¹. －1 The performance was evaluated at a temperature of 630℃ and a water ratio of 1.15 (wt). The results of physical property tests and steady-state performance are listed in Table 3.

[0111] Example 11

[0112] A method for preparing a catalyst for the dehydrogenation of low bulk density alkyl aromatics includes the following steps:

[0113] (1) Using a mixing mill, the following components were mixed uniformly: iron oxide red (equivalent to 49.25 parts Fe2O3), iron oxide yellow (equivalent to 24.63 parts Fe2O3), cerium hydroxide (equivalent to 8.45 parts CeO2), sodium nitrate (equivalent to 1.05 parts Na2O), potassium hydroxide (equivalent to 9.55 parts K2O), MoO3, magnesium carbonate (equivalent to 1.95 parts MgO), calcium carbonate (equivalent to 2.78 parts CaO), SrO, Y2O3, and zinc sulfate heptahydrate (equivalent to 1.59 parts ZnO). The mixing speed was 40.4 r / min, and the mixing time was 60 min to obtain the first mixed powder. The high-heat weight loss salts of Ce, alkali metals, and Group IIB metal salts accounted for 2.64% of the total catalyst mass, based on oxide content.

[0114] (2) Keeping the rotation speed constant, the first mixed slurry is mixed with 1.54% (wt) of organic template agent polystyrene to obtain the second mixed powder.

[0115] (3) Dissolve 0.1% (wt) of surfactant polyacrylamide, equivalent to the total catalyst mass, in 45.3% (wt) of solvent water, and sonicate at a frequency of 90 kHz for 20 min. Mix the dissolved solution with the second mixed powder to obtain a third mixed paste. Extrude the paste using a kneader, cut it into pellets with a diameter of 3 mm and a length of 5-10 mm, place them in an oven, bake at 45℃ for 8 hours, bake at 150℃ for 4 hours, and then place them in a muffle furnace for calcination at 400℃ for 6 hours and 900℃ for 4 hours to obtain the finished catalyst. The catalyst composition is listed in Table 1.

[0116] The median pore size was measured to be 263.8 nm using a mercury porosimeter, the tap density was measured to be 145.2 g / 100 ml using a tap density meter, and the crushing strength was measured to be 191.8 N / 5 mm using a DL-II intelligent particle strength meter. Simultaneously, 100 ml of catalyst was added to the reactor and incubated at atmospheric pressure and a liquid hourly space velocity (LHSV) of 1.0 h⁻¹. －1 The performance was evaluated at a temperature of 630℃ and a water ratio of 1.15 (wt). The results of physical property tests and steady-state performance are listed in Table 3.

[0117] Comparative Example 1

[0118] The catalyst was prepared according to Example 1, except that a metal salt with a high thermal weight loss rate was not used, while maintaining a constant mass ratio of template agent to oxide catalyst. The organic template agent was replaced with an inorganic template agent, silicate cement, as detailed below:

[0119] (1) Using a mixing mill, the following components were mixed evenly: iron oxide red (equivalent to 43.53 parts Fe2O3), iron oxide yellow (equivalent to 21.76 parts Fe2O3), cerium hydroxide (equivalent to 12.57 parts CeO2), potassium hydroxide (equivalent to 7.60 parts K2O), sodium hydroxide (equivalent to 0.36 parts Na2O), ammonium molybdate (equivalent to 1.79 parts MoO3), ammonium tungstate (equivalent to 1.66 parts WO3), 2.55 parts MgO, calcium hydroxide (equivalent to 1.28 parts CaO), 0.47 parts Y2O3, 0.47 parts La2O3, 0.47 parts Nd2O3, 0.47 parts Sm2O3, 0.47 parts Gd2O3, 0.47 parts Er2O3, 0.935 parts ZnO, and 0.935 parts CdO. The mixing speed was 48.5 r / min and the time was 50 min to obtain the first mixed powder.

[0120] (2) Keeping the rotation speed constant, the first mixed slurry is mixed with inorganic template agent silicate cement (Conch brand PC32.5) equivalent to 2.21% (wt) of the total catalyst mass to obtain the second mixed powder.

[0121] (3) Dissolve 0.1% (wt) of surfactant polyacrylamide, equivalent to the total catalyst mass, in 18.7% (wt) of solvent water, and sonicate at a frequency of 30 kHz for 40 min. Mix the dissolved solution with the second mixed powder to obtain a third mixed paste. Extrude the paste using a kneader, cut it into pellets with a diameter of 3 mm and a length of 5-10 mm, place them in an oven, bake at 45℃ for 8 hours, bake at 150℃ for 4 hours, and then place them in a muffle furnace for calcination at 400℃ for 6 hours and 900℃ for 4 hours to obtain the finished catalyst. The catalyst composition is listed in Table 2.

[0122] The median pore size was measured to be 203.2 nm using a mercury porosimeter, the tap density was measured to be 154.0 g / 100 ml using a tap density meter, and the crushing strength was measured to be 174.1 N / 5 mm using a DL-II intelligent particle strength meter. Simultaneously, 100 ml of catalyst was added to the reactor and incubated at atmospheric pressure and a liquid hourly space velocity (LHSV) of 1.0 h⁻¹. －1 The performance was evaluated at a temperature of 630℃ and a water ratio of 1.15 (wt). The results of physical property tests and steady-state performance are listed in Table 3.

[0123] Comparative Example 2

[0124] The catalyst was prepared according to Example 2, except that the content of the organic template agent exceeded the protection scope defined in claim 1, as follows:

[0125] (1) A mixing mill was used to uniformly mix the following components: iron oxide red (equivalent to 51.28 parts Fe2O3), iron oxide yellow (equivalent to 25.64 parts Fe2O3), cerium hydroxide (equivalent to 9.45 parts CeO2), lithium hydroxide (equivalent to 0.64 parts Li2O), sodium hydroxide (equivalent to 0.73 parts Na2O), potassium hydroxide (equivalent to 4.60 parts K2O), potassium citrate monohydrate (equivalent to 3.67 parts K2O), ammonium molybdate (equivalent to 0.53 parts MoO3), 0.64 parts CaO, 1.0 part Nd2O3, 1.0 part Er2O3, and 0.82 parts CdO. The mixing speed was 37.1 r / min, and the mixing time was 250 min to obtain the first mixed powder. Among them, the high thermal weight loss salts of Ce, alkali metals, and Group IIB metal salts accounted for 3.67% of the total catalyst mass, based on oxide content.

[0126] (2) Keeping the rotation speed constant, the first mixed slurry is mixed with 6.45% (wt) of organic template agent polystyrene, which is equivalent to the total catalyst mass fraction, to obtain the second mixed powder.

[0127] (3) Dissolve 0.1% (wt) of surfactant polyacrylamide, equivalent to the total catalyst mass, in 35.8% (wt) of solvent water, and sonicate at a frequency of 110 kHz for 10 min. Mix the dissolved solution with the second mixed powder to obtain a third mixed paste. Extrude the paste using a kneader, cut it into pellets with a diameter of 3 mm and a length of 5-10 mm, place them in an oven, bake at 45℃ for 8 hours, bake at 150℃ for 4 hours, and then place them in a muffle furnace for calcination at 400℃ for 6 hours and 900℃ for 4 hours to obtain the finished catalyst. The catalyst composition is listed in Table 2.

[0128] The median pore size was measured to be 405.8 nm using a mercury porosimeter, the tap density was measured to be 113.1 g / 100 ml using a tap density meter, and the crushing strength was measured to be 98.7 N / 5 mm using a DL-II intelligent particle strength meter. Simultaneously, 100 ml of catalyst was added to the reactor and incubated at atmospheric pressure and a liquid hourly space velocity (LHSV) of 1.0 h⁻¹. －1 The performance was evaluated at a temperature of 630℃ and a water ratio of 1.15 (wt). The results of physical property tests and steady-state performance are listed in Table 3.

[0129] Comparative Example 3

[0130] The catalyst was prepared according to the method described in Example 3, except that the raw materials did not contain metal salts with high thermal weight loss rates, as detailed below:

[0131] (1) Using a mixing mill, the following components were mixed evenly: iron oxide red (equivalent to 47.93 parts Fe2O3), iron oxide yellow (equivalent to 23.97 parts Fe2O3), cerium hydroxide (equivalent to 7.86 parts CeO2), potassium hydroxide (equivalent to 11.88 parts K2O), ammonium chromate (equivalent to 0.79 parts Cr2O3), 2.38 parts MoO3, 1.62 parts WO3, 2.80 parts SrO, 0.24 parts Y2O3, 0.24 parts Sm2O3, and 0.29 parts HgO. The mixing speed was 32.7 r / min and the time was 150 min to obtain the first mixed powder.

[0132] (2) Keeping the rotation speed constant, the first mixed slurry is mixed with 0.31% (wt) of organic template agent polystyrene, which is equivalent to the total catalyst mass, to obtain the second mixed powder.

[0133] (3) Dissolve 0.1% (wt) of surfactant polyacrylamide, equivalent to the total catalyst mass, in 57.5% (wt) of solvent water, and sonicate at a frequency of 60 kHz for 25 min. Mix the dissolved solution with the second mixed powder to obtain a third mixed paste. Extrude the paste using a kneader, cut it into pellets with a diameter of 3 mm and a length of 5-10 mm, place them in an oven, bake at 45℃ for 8 hours, bake at 150℃ for 4 hours, and then place them in a muffle furnace for calcination at 400℃ for 6 hours and 900℃ for 4 hours to obtain the finished catalyst. The catalyst composition is listed in Table 2.

[0134] The median pore size was measured to be 229.3 nm using a mercury porosimeter, the tap density was measured to be 152.9 g / 100 ml using a tap density meter, and the crushing strength was measured to be 193.2 N / 5 mm using a DL-II intelligent particle strength meter. Simultaneously, 100 ml of catalyst was added to the reactor and incubated at atmospheric pressure and a liquid hourly space velocity (LHSV) of 1.0 h⁻¹. －1 The performance was evaluated at a temperature of 630℃ and a water ratio of 1.15 (wt). The results of physical property tests and steady-state performance are listed in Table 3.

[0135] Comparative Example 4

[0136] The catalyst was prepared according to the method described in Example 11, except that the formulation did not contain Group IIB metals, while the relative contents of other components remained unchanged, as detailed below:

[0137] (1) Using a mixing mill, the following components were mixed uniformly: 50.05 parts of iron oxide red (Fe₂O₃), 25.03 parts of iron oxide yellow (Fe₂O₃), 8.58 parts of cerium hydroxide (CeO₂), 1.07 parts of sodium nitrate (Na₂O), 9.71 parts of potassium hydroxide (K₂O), 0.27 parts of MoO₃, 1.98 parts of magnesium carbonate (MgO), 2.82 parts of calcium carbonate (CaO), 0.22 parts of SrO, and 0.27 parts of Y₂O₃. The mixing speed was 40.4 r / min, and the mixing time was 60 min to obtain the first mixed powder. The high-heat weight loss salts of Ce, alkali metals, and Group IIB metals accounted for 1.07% of the total catalyst mass, based on oxide content.

[0138] (2) Keeping the rotation speed constant, the first mixed slurry is mixed with 1.54% (wt) of organic template agent polystyrene to obtain the second mixed powder.

[0139] (3) Dissolve 0.1% (wt) of surfactant polyacrylamide, equivalent to the total catalyst mass, in 45.3% (wt) of solvent water, and sonicate at a frequency of 90 kHz for 20 min. Mix the dissolved solution with the second mixed powder to obtain a third mixed paste. Extrude the paste using a kneader, cut it into pellets with a diameter of 3 mm and a length of 5-10 mm, place them in an oven, bake at 45℃ for 8 hours, bake at 150℃ for 4 hours, and then place them in a muffle furnace for calcination at 400℃ for 6 hours and 900℃ for 4 hours to obtain the finished catalyst. The catalyst composition is listed in Table 2.

[0140] The median pore size was measured to be 247.4 nm using a mercury porosimeter, the tap density was measured to be 149.5 g / 100 ml using a tap density meter, and the crushing strength was measured to be 187.3 N / 5 mm using a DL-II intelligent particle strength meter. Simultaneously, 100 ml of catalyst was added to the reactor and incubated at atmospheric pressure and a liquid hourly space velocity (LHSV) of 1.0 h⁻¹. －1 The performance was evaluated at a temperature of 630℃ and a water ratio of 1.15 (wt). The results of physical property tests and steady-state performance are listed in Table 3.

[0141] Table 1. Weight percentage composition of catalysts in Examples 1-11

[0142]

[0143]

[0144] Table 2. Weight percentage composition of catalysts in Comparative Examples 1-4

[0145]

[0146]

[0147] Table 3 Comparison of Catalyst Performance

[0148]

[0149] The above examples and comparative examples illustrate that this invention adds a certain proportion of Ce, alkali metal, and Group IIB auxiliary metal salts with high pyrolysis weight loss rates to a Fe-Ce-alkali metal-Group VIB-Alkaline earth-Group IIIB-Group IIB metal system, resulting in a synergistic effect. Simultaneously, a template agent method is employed, adding a certain amount of organic template agent and surfactant. The resulting catalyst exhibits low bulk density and good strength, maintaining high catalytic performance under reaction conditions, and can be used in the industrial production of alkyl aromatic hydrocarbon dehydrogenation.

[0150] Any numerical value mentioned in this invention, if there is only a two-unit interval between any minimum and any maximum value, includes all values ​​that increase by one unit each time from the minimum to the maximum value. For example, if the amount of a component, or the value of a process variable such as temperature, pressure, or time, is stated as 50-90, in this specification it means specifically listing values ​​such as 51-89, 52-88… and 69-71 and 70-71, etc. For non-integer values, it may be appropriately considered that a unit is 0.1, 0.01, 0.001, or 0.0001. These are merely some specifically specified examples. In this application, in a similar manner, all possible combinations of numerical values ​​between the listed minimum and maximum values ​​are considered to have been disclosed.

[0151] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A composition for preparing a catalyst for the dehydrogenation of low bulk density alkyl aromatics, characterized in that, The catalyst composition comprises a metal source and an additive; the metal source includes an Fe source, an alkali metal source, a Ce source, a Group VIB metal source, an alkaline earth metal source, a Group IIIB metal source other than Ce, and a Group IIB metal source; the additive comprises an organic template agent and a surfactant; the amount of the additive added is 0.1% to 6% of the total mass of the catalyst composition based on the oxide content; at least one of the Ce source, the alkali metal source, and the Group IIB metal source comprises a high thermal weight loss salt, and the amount of the high thermal weight loss salt added is 1% to 30% of the total mass of the catalyst composition based on the oxide content; The high-heat weight loss salt in the Ce source includes at least one of oxalate, acetate, carbonate, nitrate, and sulfate with a pyrolysis weight loss rate >40 wt%; the high-heat weight loss salt in the alkali metal source includes at least one of carbonate, oxalate, nitrate, sulfate, acetate, and citrate with a pyrolysis weight loss rate >50 wt%; the high-heat weight loss salt in the Group IIB metal source includes at least one of carbonate, nitrate, acetate, oxalate, and sulfate with a pyrolysis weight loss rate >30 wt%. The organic template agent comprises at least one of the following: polymethyl methacrylate, polyvinyl alcohol, polydivinylbenzene, polystyrene-divinylbenzene, polyvinyl acetate, polyvinyl acetate, polyquaternium salt, polyethyleneimine, polyurethane, polypyrrole, polyaniline, polythiophene, nonionic cellulose ethers, ionic cellulose ethers, sodium polyacrylate, starch, povidone, polystyrene microspheres, and cyclodextrin.

2. The composition according to claim 1, characterized in that, The amount of the group IIB metal source added is 0.001 to 3% of the total mass of the catalyst composition based on oxides; the amount of the group IIIB metal source other than Ce added is 0.05 to 4% of the total mass of the catalyst composition based on oxides.

3. The composition according to claim 1 or 2, characterized in that, The alkali metal source is selected from at least one of Li, Na, and K metal sources; and / or The VIB group metal source is selected from at least one of Cr, Mo, and W metal sources; and / or The alkaline earth metal source is selected from at least one of Mg, Ca, and Sr metal sources; and / or The group IIIB metal source other than Ce is selected from at least one of the following metal sources: Y, La, Nd, Sm, Gd, and Er; and / or The group IIB metal source is selected from at least one of Zn, Cd, and Hg metal sources; and / or The Fe source is selected from at least one of iron oxide red, iron oxide yellow, ferric nitrate, ferric citrate, and ferric ammonium citrate; and / or The alkali metal source is selected from at least one of the following: carbonates, oxalates, nitrates, sulfates, acetates, citrates, and hydroxides of alkali metals; and / or The Ce source is selected from at least one of cerium oxide, cerium oxalate, cerium acetate, cerium carbonate, cerium hydroxide, cerium nitrate, cerium sulfate, and cerium ammonium sulfate; and / or The VIB metal source is selected from at least one of the following: ammonium salts, metaammonium salts, and oxides of VIB metal; and / or The alkaline earth metal source is selected from at least one of the following: oxides, carbonates, and hydroxides of alkaline earth metals; and / or The group IIIB metal source other than Ce is selected from at least one of the following: oxides, hydroxides, carbonates, oxalates, acetates, and nitrates of group IIIB metals other than Ce; and / or The Group IIB metal source is selected from at least one of the following: oxides, hydroxides, carbonates, nitrates, acetates, oxalates, and sulfates of Group IIB metals; and / or The surfactant comprises at least one of the following: hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, hexadecylpyridine bromide, sodium dodecyl sulfate, dodecylbenzene sulfonic acid, polyacrylamide, sodium fatty alcohol ether sulfate, sodium ethoxylated fatty acid methyl ester sulfonate, sodium α-olefin sulfonate, sodium secondary alkyl sulfonate, polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, polyoxyethylene polyoxypropylene ether block copolymer, and fatty alcohol polyoxyethylene ether.

4. A catalyst for dehydrogenation of low bulk density alkyl aromatics prepared from the composition according to any one of claims 1-3.

5. The catalyst for dehydrogenation of low bulk density alkyl aromatics according to claim 4, characterized in that, It comprises the following components by weight percentage: 61–82% Fe₂O₃; 8–13% alkali metal oxides; 7–14% CeO₂; 0.1–6% Group VIB metal oxides; and 0.1–5% alkaline earth metal oxides. 0.05–4% Group IIIB metal oxides excluding Ce; 0.001–3% Group IIB metal oxides.

6. The catalyst for dehydrogenation of low bulk density alkyl aromatics according to claim 5, characterized in that, The weight ratio of the group IIIB metal oxide (excluding Ce) to the group IIB metal oxide is 0.1 to 60:

1.

7. The catalyst for dehydrogenation of low bulk density alkyl aromatics according to claim 5, characterized in that, The weight ratio of the group IIIB metal oxide (excluding Ce) to the group IIB metal oxide is 0.5 to 2.5:

1.

8. A method for preparing a catalyst for dehydrogenation of low bulk density alkyl aromatics as described in any one of claims 4-7, comprising the following steps: (1) Mix Fe source, Ce source, alkali metal source, group VIB metal source, alkaline earth metal source, group IIIB metal source other than Ce, and group IIB metal source to obtain the first mixed powder; (2) Dissolve the surfactant in a solvent to obtain a surfactant solution, and then mix the surfactant solution with the first mixed powder to obtain a second mixed slurry; (3) The second mixed slurry is mixed with the organic template agent for the third time, and the solvent is removed to obtain the third mixed paste; (4) Dry and calcine the third mixed paste.

9. The preparation method according to claim 8, characterized in that, The drying conditions for the third mixed paste are: temperature of 25–200°C and time of 6–24 h; and / or the calcination conditions are: temperature of 250–1200°C and time of 4–20 h; and / or the solvent is at least one of water, alcohol, organic amine, ammonia, and dimethyl sulfoxide; and / or the amount of solvent added is 10–80% by weight of the total mass of the catalyst based on its oxide content.

10. The application of the catalyst for dehydrogenation of low bulk density alkyl aromatics as described in any one of claims 4-7 in the dehydrogenation reaction of alkyl aromatics.

11. A method for dehydrogenating alkyl aromatics to produce alkenyl aromatics, comprising: Under the conditions for alkyl aromatic dehydrogenation reaction, alkyl aromatics, water vapor, and the catalyst for dehydrogenation of low bulk density alkyl aromatics as described in any one of claims 4-7 are brought into contact and reacted.

12. The method for dehydrogenating alkyl aromatics to alkenyl aromatics according to claim 11, characterized in that, The dehydrogenation reaction conditions for the alkyl aromatics include: a temperature of 580–650 °C and a volume hourly space velocity (VHSV) of 0.5–1.5 h⁻¹. -1 The weight ratio of water to alkyl aromatics is 0.5 to 1.3, and the pressure is 20 kPaA to 0.1 MPaA.

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