Propane dehydrogenation catalyst and preparation method thereof

Abstract

The invention provides a propane dehydrogenation catalyst and a preparation method thereof, and relates to the technical field of petrochemical engineering catalysts. The raw materials of the propane dehydrogenation catalyst comprise a carrier, an active component and an auxiliary active component, the carrier is a spherical silicon-aluminum composite carrier prepared by taking an SUZ-4-AlPO4-11 composite molecular sieve as a raw material; the active component is Pt; the auxiliary active component comprises Pt nano particles, an auxiliary active component and a surfactant. The specific carrier, the auxiliary active component and the active component Pt interact with each other, and the propylene conversion rate, the propylene selectivity and the propylene yield of the propane dehydrogenation catalyst prepared by the specific preparation method are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of petrochemical catalysts, and in particular to a propane dehydrogenation catalyst and a preparation method thereof. Background Art

[0002] Propylene, a fundamental raw material in the chemical industry, can be used to produce a range of downstream chemicals, including polymers and olefin oxides. Due to the rapid growth of downstream products in recent years, demand for propylene has been increasing. Currently, the four main sources of propylene are catalytic cracking units, ethylene crackers, propane dehydrogenation units, and methanol-to-olefins (MTO) units in the coal chemical industry. Propane dehydrogenation units and methanol-to-olefins (MTO) units in the coal chemical industry are emerging as new propylene production routes. With the increase in shale gas production in the United States, by-product ethane has gradually become the primary feedstock for steam crackers. The primary product of ethane cracking is ethylene, while the amount of propylene produced as a by-product has significantly decreased, leading to an increasingly tight propylene supply. Furthermore, the price of propane has continued to decline, attracting increasing attention to the production of propylene from propane.

[0003] Currently, propane dehydrogenation technologies are represented by UOP's Oleflex process and Lummus' Catofin process. The core of these technologies lies in efficient and stable catalysts. While Cr-based propane dehydrogenation catalysts exhibit high dehydrogenation activity and selectivity, they pose environmental challenges that are inconsistent with current environmental protection standards and are gradually being phased out. Currently, research is focused on Pt-based propane dehydrogenation catalysts, which primarily utilize the precious metal Pt as the active component and molecular sieves as the support. By adding or modifying additives or altering the properties of the support, the Pt content can be reduced in order to improve the catalyst's overall dehydrogenation performance.

[0004] The reaction performance of Pt-based catalysts for propane dehydrogenation mainly depends on their surface structure, namely electronic properties and geometric characteristics, both of which have a significant impact on the adsorption strength and adsorption configuration of the adsorbate.

[0005] Currently, catalyst stabilization strategies primarily utilize the chemical stability and physical confinement of the support. Molecular sieves, as a class of porous materials with high thermal stability and large specific surface area, are ideal confining objects for high-temperature catalytic reactions (Construction and Performance of Molecular Sieve-Encapsulated PtZn Catalysts for High Heat Sink Propane Dehydrogenation, Zhang Bofeng, PhD dissertation, Tianjin University). Their high-strength microporous structure secures the metal, ensuring its high dispersion and inhibiting its sintering and agglomeration during high-temperature calcination and reaction conditions. Molecular sieves possess ion exchange properties, uniform molecular-sized pores, acid catalytic activity, and excellent thermal and hydrothermal stability. They can be fabricated into highly active and selective catalysts for many reactions, known as molecular sieve catalysts. The application of molecular sieve catalysts in synthetic applications can significantly improve production efficiency, reduce raw material consumption, lower equipment investment costs, and increase product yield and quality. Furthermore, spent molecular sieve catalysts are environmentally friendly and pollution-free.

[0006] For example, Chinese patent application CN 114849770 A relates to a catalyst for propane oxidative dehydrogenation and its preparation method. The catalyst is an amorphous borosilicate molecular sieve material containing a composite mesoporous-microporous pore structure with micropores ranging from 0.6 to 2.0 nm and mesopores ranging from 2.0 to 10.0 nm. The preparation method comprises the following steps: dissolving a silicon source, a boron source, and an organic template in a solvent at a specific molar ratio, mixing them uniformly to form a gel, and then drying and calcining the gel to obtain the catalyst. However, the catalyst exhibits an average propylene selectivity of only 68.4% to 79.6%, and an average propane conversion of 11.8% to 24.4%.

[0007] Currently, the performance of propane dehydrogenation catalysts is primarily limited by side reactions at high temperatures, catalyst deactivation due to carbon deposition, and low propylene selectivity. Therefore, developing a molecular sieve-based propane dehydrogenation catalyst that achieves high stability, high catalytic efficiency, and high yield is of great significance. Summary of the Invention

[0008] In response to the above problems, the present invention provides a propane dehydrogenation catalyst and a preparation method thereof. By optimizing the carrier, activator and preparation method, the prepared catalyst has high stability, propylene selectivity and yield, etc.

[0009] To achieve the above object, the technical solution adopted by the present invention is as follows: In the first aspect, the present invention provides a propane dehydrogenation catalyst, the raw materials of which include a carrier, an active component and a co-active component; the carrier is a spherical silica-alumina composite carrier prepared using SUZ-4-AlPO4-11 composite molecular sieve as raw material; the active component is Pt; the co-active component includes Pt nanoparticles, a co-active ingredient and a surfactant.

[0010] Preferably, the method for preparing the carrier comprises the following steps: S1: mixing the first aluminum source, the first silicon source, the first alkali source, the first template and water, aging and calcining to obtain SUZ-4 molecular sieve; S2: The second template, the second aluminum source, the phosphorus source and water are mixed, aged and crystallized to obtain AlPO4-11 molecular sieve; S3: Mixing SUZ-4 molecular sieve and AlPO4-11 molecular sieve in a mass ratio of 1:5-10, mixing with an ammonium salt solution, drying, and calcining to obtain a SUZ-4-AlPO4-11 composite molecular sieve; S4: SUZ-4-AlPO4-11 composite molecular sieve is added with water, a molding aid and a peptizing agent to prepare a molding slurry; S5: dripping the forming slurry into a water column forming column to form spherical composite gel particles, washing, drying and calcining to obtain a spherical silicon-aluminum composite carrier.

[0011] Preferably, in step S1, the first aluminum source is aluminum oxide; Preferably, in step S1, the first silicon source is selected from silica sol; further preferably, in step S1, the first silicon source is domestic silica sol S-1430.

[0012] Preferably, in step S1, the first alkali source is sodium hydroxide or potassium hydroxide; further preferably, in step S1, the first alkali source is potassium hydroxide.

[0013] Preferably, in step S1, the first template is tetrapropylammonium bromide.

[0014] Preferably, the first aluminum source is calculated as Al2O3, the first silicon source is calculated as SiO2, and the first alkali source is calculated as KOH, and the amounts of the raw materials are as follows: mole of SiO2: mole of Al2O3: mole of KOH: mass of water = 16-35: 0.8-1.2: 5-12: 500-1200; Further preferably, the amount of raw materials used is mole of SiO2: mole of Al2O3: mole of KOH: mass of water = 22-28: 0.8-1.0: 6-10: 600-1000.

[0015] More preferably, the amount of raw materials used is mole of SiO2: mole of Al2O3: mole of KOH: mass of water = 28:1.0:8:800.

[0016] Preferably, in step S1, the molar ratio of the first silicon source to the first template is 2-10:1. Further preferably, in step S1, the molar ratio of the first silicon source to the first template is 3-8:1. More preferably, in step S1, the molar ratio of the first silicon source to the first template is 5.5:1.

[0017] Preferably, in step S1, the aging temperature is 40-60°C, and the time is 0.5-2 hours; further preferably, in step S1, the aging temperature is 50°C, and the time is 1 hour.

[0018] Preferably, in step S1, the calcination temperature is 450-550°C, and the time is 1-3 hours; further preferably, in step S1, the calcination temperature is 500°C, and the time is 2 hours.

[0019] Preferably, in step S2, the second template is tetraethylammonium hydroxide; Preferably, in step S2, the second aluminum source is aluminum oxide; Preferably, in step S2, the phosphorus source is phosphorus pentoxide; Preferably, in step S2, the amount of the second aluminum source, phosphorus source and water is the mole of Al2O3: the mole of P2O5: the mass of water = 1:0.8-1.2:35-48; Further preferably, in step S2, the amount of the second aluminum source, phosphorus source and water is the mole of Al2O3: the mole of P2O5: the mass of water = 1:1:42.

[0020] Preferably, in step S2, the amount of the second template and the second aluminum source is such that the molar ratio of the second template to Al2O3 is 2-2.5:1; Further preferably, in step S2, the amount of the second template and the second aluminum source used is such that the molar ratio of the second template to Al2O3 is 2:1.

[0021] Preferably, in step S2, the aging temperature is 70-100°C, and the time is 6-10 hours; further preferably, in step S2, the aging temperature is 75°C, and the time is 8 hours.

[0022] Preferably, in step S2, the crystallization temperature is 160-180°C, and the time is 12-18 hours; further preferably, in step S2, the crystallization temperature is 170°C, and the time is 16 hours.

[0023] Preferably, in step S3, the ammonium salt solution is an ammonium chloride solution with a concentration of 1-2 mol / L.

[0024] Preferably, in step S3, the calcination temperature is 600-750°C, and the time is 5-12 hours; further preferably, in step S3, the calcination temperature is 700°C, and the time is 6 hours.

[0025] Preferably, in step S3, the specific surface area of ​​the SUZ-4-AlPO4-11 composite molecular sieve is 100-300m 2 ·g -1 ; Preferably, in step S4, the molding aid is a soluble alginate; Further preferably, the soluble alginate is at least one selected from sodium alginate, potassium alginate, magnesium alginate and magnesium alginate.

[0026] Preferably, in step S4, the peptizing agent is selected from at least one of nitric acid, citric acid and acetic acid.

[0027] Preferably, in step S4, the molar ratio of the SUZ-4-AlPO4-11 composite molecular sieve, the molding aid and the peptizing agent is 1:0.008-0.012:0.015-0.025; Preferably, in step S4, the mass of the SUZ-4-AlPO4-11 composite molecular sieve is 30%-35% of the mass of water.

[0028] Preferably, in step S5, the calcination temperature is 500-700°C, and the time is 5-10 hours; further preferably, in step S5, the calcination temperature is 600°C, and the time is 6 hours.

[0029] Preferably, the strength of the spherical silicon-aluminum composite carrier obtained in step S5 is 70-80N.

[0030] Preferably, the mass of the active component accounts for 3‰-8‰ of the mass of the propane dehydrogenation catalyst; Preferably, the co-active ingredient is selected from at least one of sodium, potassium, magnesium, tin, lanthanum, cerium, gallium, iron and cobalt; further preferably, the co-active ingredient is sodium, potassium, tin and gallium.

[0031] Preferably, the mass of the co-active component accounts for 3‰-30‰ of the mass of the propane dehydrogenation catalyst.

[0032] Preferably, the molar ratio of sodium, potassium, tin and gallium is 1-3:2-5:2-5:0.1-0.5; more preferably, the molar ratio of sodium, potassium, tin and gallium is 2:3:3:0.2.

[0033] Preferably, the surfactant is fatty alcohol sulfate and tetradecyl dimethyl betaine.

[0034] Preferably, the molar ratio of the fatty alcohol sulfate to tetradecyl dimethyl betaine is 3-6:1-2; further preferably, the molar ratio of the fatty alcohol sulfate to tetradecyl dimethyl betaine is 3:2.

[0035] Preferably, the mass of the surfactant is 0.5%-2% of the mass of the Pt nanoparticles. Further preferably, the mass of the surfactant is 1% of the mass of the Pt nanoparticles.

[0036] Preferably, the molar ratio of the Pt nanoparticles to the co-active ingredient is 3-6:1; further preferably, the molar ratio of the Pt nanoparticles to the co-active ingredient is 4:1.

[0037] Preferably, the co-active component is a solution comprising Pt nanoparticles, a co-active ingredient and a surfactant; Preferably, in the solution, the concentration of Pt nanoparticles is 0.01 g / mL-0.10 g / mL.

[0038] In a second aspect, the present invention provides a method for preparing the above-mentioned propane dehydrogenation catalyst, comprising the following steps: Step 1: mixing chloroplatinic acid, tin chloride and gallium chloride with water to obtain a mixed solution 1; Step 2: mixing sodium hydroxide, potassium hydroxide and water to obtain a mixed solution 2; Step 3: Mix the mixed solution 1, the mixed solution 2, the Pt nanoparticles and the surfactant, impregnate the mixture onto a spherical silicon-aluminum composite support, dry and calcine to obtain a propane dehydrogenation catalyst.

[0039] Preferably, in step 3, the drying temperature is 100-150° C. and the drying time is 4-6 hours; Preferably, in step 3, the calcination temperature is 400-600° C. and the calcination time is 2-5 hours.

[0040] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention prepares a composite molecular sieve by combining SUZ-4 and AlPO4-11 molecular sieves to prepare a spherical silicon-aluminum composite carrier. On the one hand, the synergistic effect of multi-dimensional channels and one-dimensional channels can optimize the transport path of reactant molecules, reduce mass transfer resistance, and improve catalytic efficiency; on the other hand, the gradient distribution of acidic sites can realize the series catalysis of multi-step reactions (such as adsorption-dehydrogenation-isomerization), reducing the generation of side reactions; on the other hand, the obtained composite structure can prolong the catalyst life and reduce the regeneration frequency in high-temperature catalysis.

[0041] 2. The present invention optimizes the co-active components and uses fatty alcohol sulfate and tetradecyl dimethyl betaine as a surfactant dispersant combination, which significantly increases the dispersing effect of the co-activator and thus improves the catalytic efficiency of the prepared catalyst.

[0042] 3. The specific carrier, co-active component and active component Pt of the present invention interact with each other, and the propylene conversion rate, propylene selectivity and propylene yield of the propane dehydrogenation catalyst prepared by the specific preparation method are significantly improved. DETAILED DESCRIPTION

[0043] In order to make the technical means, creative features, purpose and effect of the present invention easy to understand, the present invention is further illustrated below in conjunction with specific embodiment, but the following embodiment is only a preferred embodiment of the present invention, not all. Based on the embodiment in the embodiment, other embodiments obtained by those skilled in the art without making creative work all fall within the protection scope of the present invention. It is worth noting that the raw materials used in the present invention are all common commercial products, and their source is not specifically limited. The technology and scientific terms used in the embodiment have the meaning commonly understood by those of ordinary skill in the art to which the present invention belongs.

[0044] Pt nanoparticles were purchased from Guangzhou Hongwu Material Technology Co., Ltd. with a particle size of 20 nm.

[0045] Example 1 A propane dehydrogenation catalyst, the raw materials of which include a carrier, an active component Pt and a co-active component; (1) The carrier is a spherical silicon-aluminum composite carrier prepared using SUZ-4-AlPO4-11 composite molecular sieve as raw material. The preparation method is as follows: S1: Alumina, silica sol S-1430, potassium hydroxide, tetrapropylammonium bromide and water were mixed, aged at 50°C for 1 hour, and calcined at 500°C for 2 hours to obtain SUZ-4 molecular sieve; The amount of raw materials used is the mass of SiO2 mole: Al2O3 mole: KOH mole: water = 28:1.0:8:800; The molar ratio of aluminum oxide to tetrapropylammonium bromide is 5.5:1; S2: Tetraethylammonium hydroxide, aluminum oxide, phosphorus pentoxide and water were mixed, aged at 75°C for 8 hours, and crystallized at 170°C for 16 hours to obtain AlPO4-11 molecular sieve; The molar ratio of Al2O3 to P2O5 is 2:1. S3: SUZ-4 molecular sieve and AlPO4-11 molecular sieve were mixed in a mass ratio of 1:8, mixed with a 1.5 mol / L ammonium chloride solution three times, washed to neutrality, dried, and calcined at 700 ° C for 6 h to obtain a SUZ-4-AlPO4-11 composite molecular sieve; the specific surface area of ​​the SUZ-4-AlPO4-11 composite molecular sieve is 300 m 2 ·g -1 ; S4: SUZ-4-AlPO4-11 composite molecular sieve was added with water, sodium alginate and citric acid to prepare a forming slurry; the molar ratio of SUZ-4-AlPO4-11 composite molecular sieve, sodium alginate and citric acid was 1:0.01:0.02; The mass of the SUZ-4-AlPO4-11 composite molecular sieve is 32% of the mass of water; S5: Drop the forming slurry into the water column forming column to form spherical composite gel particles, wash with water, dry, and calcine at 600°C for 6 hours in a nitrogen atmosphere to obtain a spherical silicon-aluminum composite carrier with a strength of 80N.

[0046] (2) The active component is Pt, and the mass of the active component accounts for 5‰ of the mass of the propane dehydrogenation catalyst.

[0047] (3) The co-active component consists of a solution of Pt nanoparticles, co-active ingredients and surfactants; The concentration of Pt nanoparticles was 0.05 g / mL; The auxiliary active ingredients are sodium, potassium, tin and gallium; the molar ratio of sodium, potassium, tin and gallium is 2:3:3:0.2; the total mass of the auxiliary active ingredients accounts for 15‰ of the mass of the propane dehydrogenation catalyst; The molar ratio of Pt nanoparticles and co-active ingredients was 4:1; The surfactants were fatty alcohol sulfate and tetradecyl dimethyl betaine (molar ratio 3:2), and their total mass was 1% of the mass of the Pt nanoparticles; The preparation method of the propane dehydrogenation catalyst comprises the following steps: Step 1: mixing chloroplatinic acid, tin chloride and gallium chloride with water to obtain a mixed solution 1; Step 2: mixing sodium hydroxide, potassium hydroxide and water to obtain a mixed solution 2; Step 3: Mix the mixed solution 1, the mixed solution 2, the Pt nanoparticles and the surfactant, impregnate the mixture onto a spherical silica-alumina composite support, dry the mixture at 120° C. for 5 h, and calcine the mixture at 500° C. for 3 h to obtain a propane dehydrogenation catalyst.

[0048] Example 2 A propane dehydrogenation catalyst, the raw materials of which include a carrier, an active component Pt and a co-active component; (1) The carrier is a spherical silicon-aluminum composite carrier prepared using SUZ-4-AlPO4-11 composite molecular sieve as raw material. The preparation method is as follows: S1: Alumina, silica sol S-1430, potassium hydroxide, tetrapropylammonium bromide and water were mixed, aged at 60°C for 0.5h, and calcined at 550°C for 1h to obtain SUZ-4 molecular sieve; The amount of raw materials used is the mole of SiO2: the mole of Al2O3: the mole of KOH: the mass of water = 16:0.8:5:500; The molar ratio of aluminum oxide to tetrapropylammonium bromide is 2:1; S2: Tetraethylammonium hydroxide, aluminum oxide, phosphorus pentoxide and water were mixed, aged at 100°C for 6 hours, and crystallized at 160°C for 18 hours to obtain AlPO4-11 molecular sieve; The molar ratio of Al2O3: molar of P2O5: mass of water is 1:0.8:35; the molar ratio of tetraethylammonium hydroxide to Al2O3 is 2.5:1; S3: SUZ-4 molecular sieve and AlPO4-11 molecular sieve were mixed in a mass ratio of 1:5, mixed with a 1 mol / L ammonium chloride solution for three times, washed to neutrality, dried, and calcined at 750 ° C for 5 h to obtain a SUZ-4-AlPO4-11 composite molecular sieve; the specific surface area of ​​the SUZ-4-AlPO4-11 composite molecular sieve is 100 m 2 ·g -1 ; S4: SUZ-4-AlPO4-11 composite molecular sieve was added with water, potassium alginate and nitric acid to prepare a forming slurry; the molar ratio of SUZ-4-AlPO4-11 composite molecular sieve, sodium alginate and citric acid was 1:0.008:0.015; The mass of the SUZ-4-AlPO4-11 composite molecular sieve is 30% of the mass of water; S5: dripping the forming slurry into a water column forming column to form spherical composite gel particles, washing with water, drying, and calcining at 500°C for 10 h in a nitrogen atmosphere to obtain a spherical silicon-aluminum composite support with a strength of 70N; (2) The active component is Pt, and the mass of the active component accounts for 3‰ of the mass of the propane dehydrogenation catalyst.

[0049] (3) The co-active component consists of a solution of Pt nanoparticles, co-active ingredients and surfactants; The concentration of Pt nanoparticles was 0.01 g / mL; The auxiliary active ingredients are sodium, potassium, tin and gallium; the molar ratio of sodium, potassium, tin and gallium is 1:2:2:0.1; the total mass of the auxiliary active ingredients accounts for 5‰ of the mass of the propane dehydrogenation catalyst; The molar ratio of Pt nanoparticles and co-active ingredients was 3:1; The surfactants were fatty alcohol sulfate and tetradecyl dimethyl betaine (molar ratio 3:1), and their total mass was 0.5% of the mass of the Pt nanoparticles; The preparation method of the propane dehydrogenation catalyst comprises the following steps: Step 1: mixing chloroplatinic acid, tin chloride and gallium chloride with water to obtain a mixed solution 1; Step 2: mixing sodium hydroxide, potassium hydroxide and water to obtain a mixed solution 2; Step 3: Mix the mixed solution 1, the mixed solution 2, the Pt nanoparticles and the surfactant, impregnate the mixture onto a spherical silica-alumina composite support, dry the mixture at 100° C. for 6 h, and calcine the mixture at 600° C. for 2 h to obtain a propane dehydrogenation catalyst.

[0050] Example 3 A propane dehydrogenation catalyst, the raw materials of which include a carrier, an active component Pt and a co-active component; (1) The carrier is a spherical silicon-aluminum composite carrier prepared using SUZ-4-AlPO4-11 composite molecular sieve as raw material. The preparation method is as follows: S1: Alumina, silica sol S-1430, potassium hydroxide, tetrapropylammonium bromide and water were mixed, aged at 40°C for 2 hours, and calcined at 450°C for 3 hours to obtain SUZ-4 molecular sieve; The amount of raw materials used is the mole of SiO2: the mole of Al2O3: the mole of KOH: the mass of water = 35:1.2:12:1200; The molar ratio of aluminum oxide to tetrapropylammonium bromide is 10:1; S2: Tetraethylammonium hydroxide, aluminum oxide, phosphorus pentoxide and water were mixed, aged at 75°C for 8 hours, and crystallized at 170°C for 16 hours to obtain AlPO4-11 molecular sieve; The molar ratio of Al2O3 to P2O5 is 2.2:1. S3: SUZ-4 molecular sieve and AlPO4-11 molecular sieve were mixed in a mass ratio of 1:10, mixed with a 2 mol / L ammonium chloride solution for three times, washed to neutrality, dried, and calcined at 600 ° C for 12 h to obtain a SUZ-4-AlPO4-11 composite molecular sieve; the specific surface area of ​​the SUZ-4-AlPO4-11 composite molecular sieve is 200 m 2 ·g -1 ; S4: SUZ-4-AlPO4-11 composite molecular sieve was added with water, sodium alginate and citric acid to prepare a forming slurry; the molar ratio of SUZ-4-AlPO4-11 composite molecular sieve, sodium alginate and citric acid was 1:0.012:0.025; The mass of the SUZ-4-AlPO4-11 composite molecular sieve is 35% of the mass of water; S5: Drop the forming slurry into the water column forming column to form spherical composite gel particles, wash with water, dry, and calcine at 700°C for 5h in a nitrogen atmosphere to obtain a spherical silicon-aluminum composite carrier with a strength of 75N.

[0051] (2) The active component is Pt, and the mass of the active component accounts for 8‰ of the mass of the propane dehydrogenation catalyst.

[0052] (3) The co-active component consists of a solution of Pt nanoparticles, co-active ingredients and surfactants; The concentration of Pt nanoparticles was 2 g / mL; The auxiliary active ingredients are sodium, potassium, tin and gallium; the molar ratio of sodium, potassium, tin and gallium is 3:5:5:0.5; the total mass of the auxiliary active ingredients accounts for 30‰ of the mass of the propane dehydrogenation catalyst; The molar ratio of Pt nanoparticles and co-active ingredients was 6:1; The surfactants were fatty alcohol sulfate and tetradecyl dimethyl betaine (molar ratio 6:1), and their total mass was 2% of the mass of the Pt nanoparticles; The preparation method of the propane dehydrogenation catalyst comprises the following steps: Step 1: mixing chloroplatinic acid, tin chloride and gallium chloride with water to obtain a mixed solution 1; Step 2: mixing sodium hydroxide, potassium hydroxide and water to obtain a mixed solution 2; Step 3: Mix the mixed solution 1, the mixed solution 2, the Pt nanoparticles and the surfactant, impregnate the mixture onto a spherical silica-alumina composite support, dry the mixture at 150° C. for 4 h, and calcine the mixture at 400° C. for 5 h to obtain a propane dehydrogenation catalyst.

[0053] Comparative Example 1 A propane dehydrogenation catalyst, the raw materials of which include a carrier, an active component Pt and a co-active component; (1) The carrier is a spherical silicon-aluminum composite carrier prepared using the ZSM-5 / AlPO4-5 dual-structure molecular sieve disclosed in Chinese patent application CN1524617A as raw material. The preparation method is as follows: S1: ZSM-5 / AlPO4-5 dual-structure molecular sieve was prepared by the preparation method of Example 1 of Chinese patent application CN1524617A; SUZ-4-AlPO4-11 composite molecular sieve has a specific surface area of ​​50m 2·g -1 ; S2: ZSM-5 / AlPO4-5 dual-structure molecular sieve was added with water, sodium alginate and citric acid to prepare a forming slurry; the molar ratio of ZSM-5 / AlPO4-5 dual-structure molecular sieve, sodium alginate and citric acid was 1:0.01:0.02; The mass of the ZSM-5 / AlPO4-5 dual-structure molecular sieve is 32% of the mass of water; S3: The forming slurry is dripped into the water column forming column to form spherical composite gel particles, which are washed with water, dried, and calcined at 600°C for 6 hours in a nitrogen atmosphere to obtain a spherical silicon-aluminum composite carrier with a strength of 50N.

[0054] The rest is consistent with Example 1.

[0055] Comparative Example 2 A propane dehydrogenation catalyst, compared with Example 1, the co-active component and the surfactant in the co-active component are different: It consists of a carrier, an active component Pt and co-active ingredients; (1) The carrier is the same as that in Example 1.

[0056] (2) Active ingredients and Example 1.

[0057] (3) The co-active component consists of a solution of Pt nanoparticles, co-active ingredients (sodium, potassium, tin and manganese) and surfactants; The concentration of Pt nanoparticles was 0.05 g / mL; The co-active ingredients are sodium, potassium, tin and manganese; the molar ratio of sodium, potassium, tin and manganese is 2:3:3:0.2; the total mass of the co-active ingredients accounts for 15‰ of the mass of the propane dehydrogenation catalyst; The molar ratio of Pt nanoparticles and co-active ingredients was 4:1; The surfactants were sorbitan monostearate and tetradecyl dimethyl betaine (molar ratio 3:2), and their total mass was 1% of the mass of the Pt nanoparticles; The preparation method of the propane dehydrogenation catalyst comprises the following steps: Step 1: mixing chloroplatinic acid, tin chloride and manganese chloride with water to obtain a mixed solution 1; Step 2: mixing sodium hydroxide, potassium hydroxide and water to obtain a mixed solution 2; Step 3: Mix the mixed solution 1, the mixed solution 2, the Pt nanoparticles and the surfactant, impregnate the mixture onto a spherical silica-alumina composite support, dry the mixture at 120° C. for 5 h, and calcine the mixture at 500° C. for 3 h to obtain a propane dehydrogenation catalyst.

[0058] Comparative Example 3 A propane dehydrogenation catalyst, wherein the raw materials include a carrier, an active component Pt and a co-active component (compared with Example 1, the molar ratio of the raw materials is different); (1) The carrier is a spherical silicon-aluminum composite carrier prepared using SUZ-4-AlPO4-11 composite molecular sieve as raw material. The preparation method is as follows: S1: Alumina, silica sol S-1430, potassium hydroxide, tetrapropylammonium bromide and water were mixed, aged at 50°C for 1 hour, and calcined at 500°C for 2 hours to obtain SUZ-4 molecular sieve; The amount of raw materials used is the mole of SiO2: the mole of Al2O3: the mole of KOH: the mass of water = 40:1.5:15:450; The molar ratio of aluminum oxide to tetrapropylammonium bromide is 1:1; S2: Tetraethylammonium hydroxide, aluminum oxide, phosphorus pentoxide and water were mixed, aged at 75°C for 8 hours, and crystallized at 170°C for 16 hours to obtain AlPO4-11 molecular sieve; The molar ratio of Al2O3 to P2O5 is 1:1.5:50. The molar ratio of tetraethylammonium hydroxide to Al2O3 is 1:1. S3: SUZ-4 molecular sieve and AlPO4-11 molecular sieve were mixed in a mass ratio of 1:15, mixed with a 1.5 mol / L ammonium chloride solution three times, washed to neutrality, dried, and calcined at 700 ° C for 6 h to obtain a SUZ-4-AlPO4-11 composite molecular sieve; the specific surface area of ​​the SUZ-4-AlPO4-11 composite molecular sieve is 80 m 2 ·g -1 ; S4: SUZ-4-AlPO4-11 composite molecular sieve was added with water, sodium alginate and citric acid to prepare a forming slurry; the molar ratio of SUZ-4-AlPO4-11 composite molecular sieve, sodium alginate and citric acid was 1:0.015:0.030; The mass of the SUZ-4-AlPO4-11 composite molecular sieve is 40% of the mass of water; S5: The forming slurry is dripped into the water column forming column to form spherical composite gel particles, which are washed with water, dried, and calcined at 600°C for 6 hours in a nitrogen atmosphere to obtain a spherical silicon-aluminum composite carrier with a strength of 55N.

[0059] (2) The active component is Pt, and the mass of the active component accounts for 10‰ of the mass of the propane dehydrogenation catalyst.

[0060] (3) The co-active component consists of a solution of Pt nanoparticles, co-active ingredients and surfactants; The concentration of Pt nanoparticles was 0.05 g / mL; The auxiliary active ingredients are sodium, potassium, tin and gallium; the molar ratio of sodium, potassium, tin and gallium is 4:1:1:1; the total mass of the auxiliary active ingredients accounts for 35‰ of the mass of the propane dehydrogenation catalyst; The molar ratio of Pt nanoparticles and co-active ingredients was 1:1; The surfactants were fatty alcohol sulfate and tetradecyl dimethyl betaine (molar ratio of 1:1), and their total mass was 3% of the mass of the Pt nanoparticles; The preparation method of the propane dehydrogenation catalyst comprises the following steps: Step 1: mixing chloroplatinic acid, tin chloride and gallium chloride with water to obtain a mixed solution 1; Step 2: mixing sodium hydroxide, potassium hydroxide and water to obtain a mixed solution 2; Step 3: Mix the mixed solution 1, the mixed solution 2, the Pt nanoparticles and the surfactant, impregnate the mixture onto a spherical silica-alumina composite support, dry the mixture at 120° C. for 5 h, and calcine the mixture at 500° C. for 3 h to obtain a propane dehydrogenation catalyst.

[0061] Test Case The catalysts prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were used to carry out propane oxidative dehydrogenation reaction. Before the reaction, 5 g of the catalyst was loaded into a fixed bed reactor. The reaction temperature was 610 ° C., the reaction pressure was atmospheric pressure, and the reaction gas composition was: propane / hydrogen = 1:1 (V / V); the space velocity was 1500 h -1 The reaction gas was passed into a reactor loaded with the above catalyst for 1 hour and 30 hours, and the products were respectively passed into a gas chromatograph and analyzed using a GC 7900 gas chromatograph. The test results are shown in Table 1.

[0062] Table 1. Catalyst performance

[0063] As can be seen from Table 1, the catalyst prepared with the specific components and proportions of the present invention has significantly improved propylene conversion, propylene selectivity and propylene yield.

[0064] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A propane dehydrogenation catalyst, characterized in that The raw materials include a carrier, an active component and a co-active component; the carrier is a spherical silicon-aluminum composite carrier prepared using SUZ-4-AlPO4-11 composite molecular sieve as a raw material; the active component is Pt; and the co-active component includes Pt nanoparticles, co-active ingredients and a surfactant.

2. The propane dehydrogenation catalyst according to claim 1, characterized in that The preparation method of the carrier comprises the following steps: S1: mixing the first aluminum source, the first silicon source, the first alkali source, the first template and water, aging and calcining to obtain SUZ-4 molecular sieve; S2: The second template, the second aluminum source, the phosphorus source and water are mixed, aged and crystallized to obtain AlPO4-11 molecular sieve; S3: Mixing SUZ-4 molecular sieve and AlPO4-11 molecular sieve in a mass ratio of 1:5-10, mixing with an ammonium salt solution, drying, and calcining to obtain a SUZ-4-AlPO4-11 composite molecular sieve; S4: SUZ-4-AlPO4-11 composite molecular sieve is added with water, a molding aid and a peptizing agent to prepare a molding slurry; S5: dripping the forming slurry into a water column forming column to form spherical composite gel particles, washing, drying and calcining to obtain a spherical silicon-aluminum composite carrier.

3. The propane dehydrogenation catalyst according to claim 2, characterized in that In step S1, the first aluminum source is aluminum oxide; the first silicon source is silica sol; the first alkali source is potassium hydroxide; and the first template is tetrapropylammonium bromide; The first aluminum source is calculated as Al2O3, the first silicon source is calculated as SiO2, and the first alkali source is calculated as KOH. The amounts of the raw materials are as follows: mole of SiO2: mole of Al2O3: mole of KOH: mass of water = 16-35: 0.8-1.2: 5-12: 500-1200; The molar ratio of the first silicon source to the first template is 2-10:1; The aging temperature is 40-60°C and the aging time is 0.5-2h; The calcination temperature is 450-550° C. and the calcination time is 1-3 hours.

4. The propane dehydrogenation catalyst according to claim 2, characterized in that In step S2, the second template is tetraethylammonium hydroxide; the second aluminum source is aluminum oxide; and the phosphorus source is phosphorus pentoxide; The amount of the second aluminum source, phosphorus source and water is mol of Al2O3:mol of P2O5:mass of water=1:0.8-1.2:35-48; The amount of the second template and the second aluminum source is such that the molar ratio of the second template to Al2O3 is 2-2.5:1; The aging temperature is 70-100°C and the time is 6-10h; The crystallization temperature is 160-180° C., and the crystallization time is 12-18 hours.

5. The propane dehydrogenation catalyst according to claim 2, characterized in that In step S3, the ammonium salt solution is an ammonium chloride solution with a concentration of 1-2 mol / L; the roasting temperature is 600-750° C., and the roasting time is 5-12 hours.

6. The propane dehydrogenation catalyst according to claim 2, characterized in that In step S4, the molding aid is a soluble alginate; the peptizing agent is selected from at least one of nitric acid, citric acid and acetic acid; in step S5, the calcination temperature is 500-700°C and the time is 5-10h; the strength of the spherical silicon-aluminum composite carrier obtained in step S5 is 70-80N.

7. The propane dehydrogenation catalyst according to claim 1, characterized in that The mass of the active component accounts for 3‰-8‰ of the mass of the propane dehydrogenation catalyst; the mass of the auxiliary active component accounts for 3‰-30‰ of the mass of the propane dehydrogenation catalyst; the auxiliary active component is selected from at least one of sodium, potassium, magnesium, tin, lanthanum, cerium, gallium, iron and cobalt.

8. The propane dehydrogenation catalyst according to claim 7, characterized in that The auxiliary active ingredients are sodium, potassium, tin and gallium; the molar ratio of sodium, potassium, tin and gallium is 1-3:2-5:2-5:0.1-0.

5.

9. The propane dehydrogenation catalyst according to claim 1, characterized in that The surfactants are fatty alcohol sulfate and tetradecyl dimethyl betaine; the molar ratio of the fatty alcohol sulfate to tetradecyl dimethyl betaine is 3-6:1-2; the mass of the surfactant is 0.5%-2% of the mass of the Pt nanoparticles; and the molar ratio of the Pt nanoparticles to the co-active ingredient is 3-6:

1.

10. The method for preparing the propane dehydrogenation catalyst according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step 1: mixing chloroplatinic acid, tin chloride and gallium chloride with water to obtain a mixed solution 1; Step 2: mixing sodium hydroxide, potassium hydroxide and water to obtain a mixed solution 2; Step 3: Mix the mixed solution 1, the mixed solution 2, the Pt nanoparticles and the surfactant, impregnate the mixture onto a spherical silicon-aluminum composite support, dry and calcine to obtain a propane dehydrogenation catalyst.

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