C3 fraction selective hydrogenation catalyst as well as preparation method and application thereof

Abstract

The invention provides a C3 fraction selective catalyst. The catalyst comprises a carrier and an active component loaded on the carrier, wherein the carrier is a metal composite oxide modified by an organic cation quaternary ammonium salt and a silane reagent; the metal element I in the metal composite oxide comprises aluminum and titanium; the metal element II in the active component comprises a main active component noble metal Pd and an optional auxiliary active component, the auxiliary active component comprises transition metal and / or alkaline earth metal, the transition metal is selected from one or more of Cu, Mn, Ni and Zn, and the alkaline earth metal is selected from one or more of Ca, Mg and Ba. The carrier is modified through the organic cation quaternary ammonium salt and the silane reagent, the dispersity of active components on the surface of the carrier can be remarkably improved, and the problem that the crushing strength of metal composite oxide is low is solved. The invention also provides a preparation method and application of the C3 fraction selective catalyst, and also provides a method for producing propylene through selective hydrogenation of C3 fractions.

Description

Technical Field

[0001] This invention relates to the field of selective hydrogenation technology for C3 fractions, specifically to a selective hydrogenation catalyst for C3 fractions, its preparation method, and its application in the selective hydrogenation of C3 fractions to produce propylene. Background Technology

[0002] Propylene is an important basic chemical raw material and one of the three major synthetic materials. Its largest use is in the production of polypropylene. It can also be used to produce acrylonitrile, propylene oxide, acrolein, acrylic acid, phenol, acetone, etc. Its downstream products have wide applications in films, fibers, rubber, resins, coatings and other fields.

[0003] Currently, with the continuous expansion of propylene production, reaching 56 million tons / year by 2022, and annual consumption reaching 48 million tons / year, the supply of propylene has gradually shifted from imports to domestic production. However, the structural overcapacity of propylene has led to higher demands on the downstream industries, and stricter requirements for the refining of propylene feedstocks. Propylene is typically obtained in petroleum cracking to ethylene production units. The C3 fraction in the cracked gas typically consists of 92-96% propylene, 2.9-3.5% propane, and 1-5% propyne (MA) and propadiene (PD). MAPD is a toxic substance that affects downstream propylene applications; therefore, removing MAPD is essential for obtaining high-purity propylene.

[0004] In C3 fractions, MAPD readily polymerizes into a gel at high temperatures, depositing on the catalyst surface and causing rapid catalyst deactivation, necessitating frequent activation and regeneration. Therefore, it is desirable for hydrogenation catalysts to possess high low-temperature activity, maintaining appropriate gel-coating capacity so that the polymers on the catalyst surface remain active before being washed away, thereby extending catalyst lifespan. This is crucial in industrial production.

[0005] Industrial removal of MAPD from C3 fractions mainly includes gas-phase catalytic selective hydrogenation, liquid-phase catalytic selective hydrogenation, and catalytic distillation. Currently, liquid-phase selective hydrogenation is commonly used due to its simple process flow, low reaction temperature, low energy consumption, safety, environmental friendliness, and ease of operation. Selective hydrogenation of C3 fractions requires high precision in catalyst selection and reaction process control. Currently, industrial selective hydrogenation catalysts for C3 fractions are supported catalysts with palladium as the main active component and alumina as the carrier; some also incorporate silver, gold, copper, and other additives to improve propylene selectivity.

[0006] However, current catalysts for the selective hydrogenation of industrial C3 fractions to remove propyne and propadiene still suffer from problems such as low activity, poor stability, and low selectivity for propylene. Summary of the Invention

[0007] To address at least one of the aforementioned problems in the prior art, this invention proposes a C3 fraction selective hydrogenation catalyst, its preparation method, and its application in the selective hydrogenation of C3 fractions to produce propylene. This hydrogenation catalyst can convert propyne and propadiene into propylene during selective hydrogenation, while simultaneously inhibiting the further hydrogenation of propylene into propane.

[0008] Therefore, in a first aspect, the present invention provides a C3 fraction selective hydrogenation catalyst, comprising a support and an active component supported on the support.

[0009] The carrier is a metal composite oxide modified with organic cationic quaternary ammonium salt and silane reagents; the metal composite oxide contains metal element I, which includes aluminum and titanium;

[0010] The active component II includes the main active component Pd and optional auxiliary active components. The auxiliary active components include transition metals and / or alkaline earth metals. The transition metals are selected from one or more of Cu, Mn, Ni, and Zn, and the alkaline earth metals are selected from one or more of Ca, Mg, and Ba.

[0011] The support in this invention is treated with organic cationic quaternary ammonium salts and silane reagents, which solves the problem of low crushing strength of metal composite oxides caused by the introduction of Ti. The support has higher crushing strength, which can effectively avoid the pulverization problem of catalysts during long-term operation. Furthermore, it can be produced by extrusion, utilizing irregular surfaces to increase the contact area between the catalyst's outer surface and physical surfaces, thereby improving catalyst activity. Simultaneously, the modified composite oxide support provided by this invention, through the introduction of organic cationic quaternary ammonium salts and silane reagents, can further improve the dispersion of active components on the support surface, controlling the particle size of the nanoclusters formed by the active components on the support surface to below 5 nm, thus significantly improving the low-temperature activity of the catalyst.

[0012] In a specific embodiment of the present invention, the transition metal is preferably Cu; the alkaline earth metal is preferably Ca.

[0013] As a specific embodiment of the present invention, the organic cationic quaternary ammonium salt includes a hydrocarbon-based quaternary ammonium salt.

[0014] As a specific embodiment of the present invention, the general formula of the hydrocarbon-based quaternary ammonium salt is R4N. + X - , where X - Selected from halide ions and acid radical ions, preferably, the halide ions include F. - Cl - ,Br - and I- The acid radical ions include nitrate ions and carboxylate ions, with the general formula R4N. + X - Each R may be the same or different, and each is independently selected from alkyl, cycloalkyl, aryl, aralkyl and alkylaryl. At least one R is selected from alkyl groups of C6 or above, preferably from C6 to C20 alkyl groups, and the remaining Rs are preferably selected from C1 to C4 alkyl groups and C7 to C11 aralkyl groups.

[0015] As a specific embodiment of the present invention, the general formula R4N + X - The Rs may be the same or different, and 1 to 2 Rs are selected from alkyl groups of C6 or above, preferably from C6 to 20 alkyl groups, and the remaining Rs are preferably selected from C1 to C4 alkyl groups or C7 to C11 aryl alkyl groups.

[0016] As a specific embodiment of the present invention, the organic cationic quaternary ammonium salt includes at least one of bis(octadecyl)dimethyl quaternary ammonium salt, hexadecyltrimethyl quaternary ammonium salt, and C12-18 alkyldimethylbenzyl quaternary ammonium salt.

[0017] As a specific embodiment of the present invention, the organic cationic quaternary ammonium salt is selected from at least one of bis(octadecyl)dimethylammonium chloride, hexadecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, dodecyldimethylbenzylammonium chloride, tetradecyldimethylbenzylammonium chloride, hexadecyldimethylbenzylammonium chloride and octadecyldimethylbenzylammonium chloride.

[0018] As a specific embodiment of the present invention, the general formula of the silane reagent is SiR. 1 x (OR 2 ) y Where x and y are each independently selected from integers from 1 to 3, x + y = 4, R 1 Selected from hydrogen, C1-C6 alkyl and C2-C6 alkenyl, R 2 Selected from C1 to C6 alkyl groups.

[0019] As a specific embodiment of the present invention, the silane reagent includes at least one selected from triethoxysilane, trimethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane. The methoxy and ethoxy functional groups in the above-mentioned silane reagents bind to the hydroxyl groups on the support surface, improving the dispersibility of metals and their oxides on the surface and reducing particle size.

[0020] In a specific embodiment of the present invention, the amount of the organic cationic quaternary ammonium salt is 1%-50% of the mass of the metal composite oxide. According to the present invention, controlling the above ratio can increase the hydroxyl groups on the carrier surface and improve the affinity between the carrier surface and the additives.

[0021] In a specific embodiment of the present invention, the amount of the organic cationic quaternary ammonium salt is 30%-50% of the mass of the metal composite oxide. According to the present invention, controlling the above ratio can further increase the hydroxyl groups on the carrier surface and improve the affinity between the carrier surface and the additives.

[0022] In a specific embodiment of the present invention, the amount of the organic cationic quaternary ammonium salt is 35%-50% of the mass of the metal composite oxide. According to the present invention, controlling the above ratio can further increase the hydroxyl groups on the carrier surface and improve the affinity between the carrier surface and the additives.

[0023] In a specific embodiment of the present invention, the amount of the silane reagent is 0.5%-30% of the mass of the metal composite oxide. According to the present invention, controlling the above ratio can increase the hydrophobicity of the support surface and improve the dispersion of the catalyst active component on the support surface.

[0024] In a specific embodiment of the present invention, the amount of the silane reagent is 0.5%-15% of the mass of the metal composite oxide. According to the present invention, controlling the above ratio can further improve the hydrophobicity of the support surface and increase the dispersion of the catalyst active component on the support surface.

[0025] In a specific embodiment of the present invention, the amount of the silane reagent is 0.5%-10% of the mass of the metal composite oxide. According to the present invention, controlling the above ratio can further improve the hydrophobicity of the support surface and increase the dispersion of the catalyst active component on the support surface.

[0026] In a specific embodiment of the present invention, the carrier is a SiO2-TiO2-Al2O3 composite oxide.

[0027] As a specific embodiment of the present invention, based on the carrier, the content of Ti in the carrier, calculated as TiO2, is 5wt% to 25wt%, the content of Al, calculated as Al2O3, is 65wt% to 90wt%, and the content of Si, calculated as SiO2, is 0.5wt% to 15wt%.

[0028] As a specific embodiment of the present invention, based on the carrier, the content of Al2O3 in the carrier is 80wt% to 90wt%.

[0029] As a specific embodiment of the present invention, the metal composite oxide is an Al2O3-TiO2 composite oxide.

[0030] As a specific embodiment of the present invention, based on the metal composite oxide, the content of Ti in the metal composite oxide, calculated as TiO2, is 5-30 wt%; and the content of Al, calculated as Al2O3, is 70-95 wt%. According to the present invention, controlling Al2O3 and TiO2 in the above-mentioned ratio can improve crushing strength, increase specific surface area and pore volume, improve the electronic properties of the catalyst surface, and enhance catalyst activity.

[0031] As a specific embodiment of the present invention, based on the metal composite oxide, the content of Ti in the metal composite oxide, calculated as TiO2, is 8wt% to 25wt%; and the content of Al, calculated as Al2O3, is 75wt% to 92wt%. According to the present invention, controlling Al2O3 and TiO2 in the above-mentioned ratio can further improve the crushing strength, the larger specific surface area and pore volume, improve the electronic properties of the catalyst surface, and enhance the catalyst activity.

[0032] In a specific embodiment of the present invention, the specific surface area of ​​the carrier is 30–150 μm. 2 / g, preferably 50-90m 2 / g.

[0033] As a specific embodiment of the present invention, the pore volume of the carrier is 0.2 to 0.8 mL / g, preferably 0.3 to 0.5 mL / g.

[0034] As a specific embodiment of the present invention, based on 100 parts by mass of the metal composite oxide, the content of the precious metal, calculated as oxide, is 0.1 to 0.5 parts.

[0035] As a specific embodiment of the present invention, based on 100 parts by mass of the metal composite oxide, the content of the transition metal, calculated as oxide, is 1 to 5 parts.

[0036] As a specific embodiment of the present invention, based on 100 parts by mass of the metal composite oxide, the content of the alkaline earth metal, calculated as oxide, is 1 to 5 parts, preferably 3 to 5 parts.

[0037] In a specific embodiment of the present invention, the active component is distributed on the carrier in the form of nanoclusters, wherein the particle size of the nanoclusters is less than 5 nm.

[0038] As a specific embodiment of the present invention, each active component in the catalyst exists in the form of its element or oxide.

[0039] As a specific embodiment of the present invention, the catalyst is activated with hydrogen before use.

[0040] As a specific embodiment of the present invention, the activation treatment conditions include: activation temperature of 300-600℃, activation pressure of 0-3.0MPa, hydrogen flow rate relative to catalyst of 1mL / min·g-15mL / min·g, and activation time of 6h-18h.

[0041] As a specific embodiment of the present invention, the preparation of the carrier includes the following steps: after the metal composite oxide is subjected to a first treatment with an organic cationic quaternary ammonium salt solution, it is subjected to a second treatment with a silane reagent to obtain the carrier.

[0042] The support in this invention employs an organic cationic quaternary ammonium salt solution and silane reagents to treat the metal composite oxide, which significantly improves the dispersion of the active components on the support surface and controls the active component metal nanoclusters to be below 5 nm. The support obtained through this treatment solves the problem of low crushing strength of the metal composite oxide caused by the introduction of Ti. Higher crushing strength effectively avoids pulverization of the catalyst during long-term operation. Furthermore, it can be produced using an extrusion method, utilizing a shaped surface to increase the contact area between the catalyst's outer surface and physical surfaces, thereby enhancing the catalyst's activity.

[0043] In a specific embodiment of the present invention, the first treatment includes a first impregnation and a first drying performed sequentially. According to the present invention, using an organic cationic quaternary ammonium salt solution to impregnate the metal composite oxide can effectively control the possibility of metal ions participating in the oxidation reaction.

[0044] As a specific embodiment of the present invention, the second treatment includes adding a solution of silane reagent dropwise to the metal composite oxide that has been treated in the first treatment, followed by stirring, second drying and first calcination, preferably with a stirring time of 1 min to 60 min.

[0045] As a specific embodiment of the present invention, the solvent of the organic cationic quaternary ammonium salt solution includes at least one of water, methanol, ethanol, benzene, toluene, chloroethane, isopropanol, acetone, sulfuric acid, hydrochloric acid, nitric acid, sodium hydroxide, and potassium hydroxide, preferably methanol.

[0046] As a specific embodiment of the present invention, the concentration of the organic cation quaternary ammonium salt solution is 0.1 wt% to 10 wt%, preferably 0.2 to 10 wt%, and more preferably 1 to 5 wt%.

[0047] As a specific embodiment of the present invention, the silane reagent may be, but is not limited to, an aqueous solution of a silane reagent.

[0048] As a specific embodiment of the present invention, the solution of the silane reagent is an aqueous solution of the silane reagent with a concentration of 0.1-10 wt%, preferably 1-10 wt%.

[0049] As a specific embodiment of the present invention, the conditions for the first impregnation include: impregnation temperature of 10°C to 50°C, and impregnation time of 1 hour to 12 hours, preferably 1 hour to 8 hours.

[0050] As a specific embodiment of the present invention, the conditions for the first drying and the second drying are the same or different, and each independently includes: a drying temperature of 60℃~150℃, preferably 60℃~110℃, and a drying time of 4h~12h.

[0051] As a specific embodiment of the present invention, the conditions for the first roasting include: a roasting temperature of 300-1100°C, preferably 500-900°C, and a roasting time of 4-12 hours.

[0052] Therefore, in a second aspect, the present invention provides a method for preparing the above-mentioned selective hydrogenation catalyst for C3 fractions, comprising the following steps:

[0053] S1. The support is impregnated with a solution containing optional active components in the second stage, followed by a third drying and a second calcination to obtain the catalyst precursor;

[0054] S2. The catalyst precursor is impregnated with a solution containing the main active component in the third stage, followed by a fourth stage of drying and a third stage of calcination to obtain the catalyst.

[0055] The selective hydrogenation catalyst provided by this invention, through the combination of a specific support and active components, yields a noble metal selective hydrogenation catalyst with high reactivity and selectivity.

[0056] As a specific embodiment of the present invention, the conditions for the second impregnation and the third impregnation may be the same or different, and each independently includes: a temperature of 20°C to 70°C, preferably 20°C to 40°C, and a time of 1 hour to 12 hours, preferably 1 hour to 4 hours.

[0057] As a specific embodiment of the present invention, the conditions for the third drying and the fourth drying are the same or different, and each independently includes: a temperature of 60 to 150°C, preferably 100 to 150°C, and a time of 1 to 8 hours, preferably 4 to 8 hours.

[0058] As a specific embodiment of the present invention, the conditions for the second and third calcinations may be the same or different, and each independently includes: a temperature of 300-600°C, preferably 400-500°C, a time of 4-12 hours, and / or, a calcination atmosphere of air and / or nitrogen.

[0059] In a specific embodiment of the present invention, the water absorption rate of the support is first determined when preparing the catalyst. Specifically, a suitable amount of support (mass A) is weighed, soaked in a suitable amount of deionized water for 15–120 minutes, and excess water is absorbed with filter paper until the support is just completely wetted. The weight is then measured (mass B). The water absorption rate of the support is calculated as (BA) / A*100%.

[0060] In a specific embodiment of the present invention, the volume of the solution containing the co-active component is 0.8 to 2.5 times the pore volume of the carrier.

[0061] As a specific embodiment of the present invention, the concentration of the metal salt solution is prepared according to the water absorption rate of the carrier and the equal volume impregnation method.

[0062] As a specific embodiment of the present invention, the concentration of the alkaline earth metal solution is 0.1 to 0.6 mol / L, preferably 0.5 to 2.5 mol / L.

[0063] In a specific embodiment of the present invention, the concentration of the transition metal-containing solution is 0.1 to 1.5 mol / L.

[0064] As a specific embodiment of the present invention, the concentration of the solution containing the main active component is 0.01 to 0.3 mol / L, preferably 0.01 to 0.15 mol / L.

[0065] As a specific embodiment of the present invention, the solution containing the auxiliary active component is a hydrochloride solution, a sulfate solution, or a nitrate solution.

[0066] As a specific embodiment of the present invention, the solution containing the main active component is a hydrochloride solution, a sulfate solution, or a nitrate solution.

[0067] In a specific embodiment of the present invention, the Pd salt in the solution containing the main active component includes one or more of the following palladium organic acid salts: palladium chloride, palladium nitrate, palladium sulfate, sodium tetranitrate palladiumate, palladium acetate, and palladium propionate. The present invention does not particularly limit the type of palladium salt solution; it can be an aqueous solution or a palladium salt solution formed using ethanol, benzene, or other organic solvents. An aqueous solution of palladium salt is preferred.

[0068] As a specific embodiment of the present invention, the Cu salt in the transition metal solution includes one or more of copper chloride, copper nitrate, and copper sulfate. The present invention does not particularly limit the type of copper salt solution; it can be an aqueous solution or a copper salt solution formed using organic solvents such as ethanol or benzene. Preferably, it is an aqueous solution of copper salt, which is lower in cost and more environmentally friendly than copper salt solutions using organic solvents.

[0069] As a specific embodiment of the present invention, the Ca salt in the alkaline earth metal solution includes one or more of calcium oxalate, calcium acetate, calcium sulfate, calcium carbonate, and organic acid salts. The present invention does not particularly limit the type of calcium salt solution, which can be an aqueous solution or a salt solution formed by using ethanol, benzene, etc. as organic solvents. Preferably, it is an aqueous solution of calcium salt. Compared with salt solutions prepared with organic solvents, aqueous solutions of salt are low in cost and environmentally friendly.

[0070] As a specific embodiment of the present invention, the solvents of the optional solution containing the auxiliary active component and the solution containing the main active component may be the same or different, and each independently includes at least one of water, sulfuric acid, hydrochloric acid, nitric acid, methanol and ethanol.

[0071] Therefore, in a third aspect, the present invention provides the application of the above-described hydrogenation catalyst or the hydrogenation catalyst prepared by the above-described preparation method in the selective hydrogenation of C3 fractions to produce propylene.

[0072] As a specific embodiment of the present invention, the C3 fraction includes propylene and propane.

[0073] As a specific embodiment of the present invention, the C3 fraction contains impurities, the impurities being propyne and / or propylene.

[0074] As a specific embodiment of the present invention, the C3 fraction contains the following components: 80wt% to 99.99wt% propylene.

[0075] As a specific embodiment of the present invention, the C3 fraction contains the following components: propane 0wt% to 19.99wt%.

[0076] As a specific embodiment of the present invention, the C3 fraction contains the following components: 0.01 wt% to 5 wt% propyne.

[0077] As a specific embodiment of the present invention, the C3 fraction contains the following components: 0% to 5% propylene.

[0078] As a specific embodiment of the present invention, the conditions for the hydrogenation reaction include: using a fixed-bed reactor, a reactor inlet temperature of 20–50°C, a molar ratio of hydrogen to (alkyne + diene) of 1–2.5:1, a pressure of 0.5–0.8 MPa, a recycle ratio of 10–30:1, and a volume hourly space velocity of 1–3 h⁻¹. -1 .

[0079] Therefore, in a fourth aspect, the present invention provides a method for selective hydrogenation of a C3 fraction to produce propylene, comprising: selectively hydrogenating propyne and propadiene in the C3 fraction with hydrogen in the presence of the above-mentioned C3 fraction selective hydrogenation catalyst or the C3 fraction selective hydrogenation catalyst prepared by the above-mentioned preparation method to produce propylene.

[0080] As a specific embodiment of the present invention, the hydrogenation catalyst is first activated and reduced. Preferably, the activation and reduction conditions include: activation and reduction using hydrogen gas, with a hydrogen flow rate of 1 to 15 mL / min·g relative to the catalyst, an activation temperature of 300 to 600°C, an activation pressure of 0 to 3.0 MPa, and an activation time of 6 to 18 h.

[0081] As a specific embodiment of the present invention, the conditions for selecting the hydrogenation reaction include: using a fixed-bed reactor, a reactor inlet temperature of 20–50°C, a hydrogen to (alkyne + diene) molar ratio of 1–2.5:1, a pressure of 0.5–0.8 MPa, a recycle ratio of 10–30:1, and a volume hourly space velocity of 1–3 h⁻¹. -1 .

[0082] As a specific embodiment of the present invention, the C3 fraction contains impurities, the impurities being propyne and / or propylene.

[0083] As a specific embodiment of the present invention, the C3 fraction comprises the following components: propylene 80wt% to 99.99wt%, and / or propane 0wt% to 19.99wt%, and / or propyne 0.01wt% to 5wt%, and / or propadiene 0% to 5%.

[0084] In a specific embodiment of the present invention, the hydrogenation reaction is carried out in a fixed-bed reactor, with 25-100 mL of catalyst loaded.

[0085] This invention has the following advantages:

[0086] (1) The metal composite oxide in this invention undergoes surface treatment with organic cationic quaternary ammonium salts and silane reagents, overcoming the disadvantage of low crushing strength caused by the introduction of TiO2 into the support. This allows the prepared catalyst to effectively avoid pulverization during long-term operation and enables production via extrusion, utilizing the irregular surface to increase the contact area between the catalyst's outer surface and physical surfaces, thereby enhancing catalyst activity. Simultaneously, treatment with organic cationic quaternary ammonium salts and silane reagents significantly improves the dispersion of active components on the support surface, controlling the particle size of the nanoclusters formed by the active components on the support surface to below 5 nm, thus significantly improving the low-temperature activity of the catalyst.

[0087] (2) The catalyst of the present invention has high low-temperature reaction activity and selectivity, its preparation process is simple, the reaction conditions are mild, the production cost is low, and it can operate stably for a long time in production, which has industrial application value.

[0088] (3) The catalyst for selective hydrogenation of C3 fractions to remove impurities propyne and propadiene provided by the present invention has the advantages of high selectivity, high low-temperature activity, and stable hydrogenation activity, and can be used for a long period of time. Detailed Implementation

[0089] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0090] (I) Measurement Method

[0091] The TiO2 content was determined using a spectrophotometer, and the parameter detection method was the standard curve method. The principle utilized was that in sulfuric acid solution, Ti... 4+ It forms a yellow complex with hydrogen peroxide. Titanium dioxide reacts with hot sulfuric acid to form titanyl sulfate, which then reacts with hydrogen peroxide to form a stable, orange-yellow [TiO(H₂O₂)]₂. 2- The results were measured at 430 nm using a spectrophotometer.

[0092] The specific surface area and pore volume of the support were determined using an ASAP 2020 adsorption analyzer (N2 adsorption-desorption method) from Micron Instruments, Inc., USA. The parameters were measured using the static volumetric method. Before testing, the catalyst samples were degassed at 623 K for 4 h and then adsorbed with nitrogen at liquid nitrogen temperature. Sample data were processed using AMSM software, and the specific surface area was obtained using the Brunauer-Emmet-Teller (BET) method. The average pore size was obtained from the nitrogen adsorption isotherm using the Barrett-Joyner-Halenda (BJH) method, and the pore volume was obtained using the P / Po single-point desorption curve.

[0093] The metal content of active components such as Pd, Cu, and Ca in the catalyst was determined using an ICP atomic emission spectrometer, based on the JYT015 General Rules for Inductively Coupled Plasma Atomic Emission Spectrometry. A PerkinElmer (PE) Optima 8300 full-spectrum direct-reading ICP spectrometer with an echelle grating, solid-state detector, and dual-path dual-solid-state detectors in the ultraviolet and visible regions was used, employing flat-plate plasma technology to ensure minimal argon consumption.

[0094] Preparation Example 1

[0095] The selected material is a TiO2-Al2O3 composite oxide produced by Yantai Heng Hui Chemical Co., Ltd., containing 15wt% TiO2 and 85wt% Al2O3, with a specific surface area of ​​60m². 2 / g, pore volume 0.55mL / g.

[0096] 100g of TiO2-Al2O3 composite oxide was impregnated with 1L of a 5wt% dimethyl dioctadecyl ammonium chloride methanol solution for 2h, and then dried at 70℃ for 10h. 100g of a 2wt% vinyltrimethoxysilane aqueous solution was added dropwise to the dried composite oxide. After the addition was completed, the resulting mixture was stirred uniformly for 10 minutes. The mixture was then dried at 70℃ for 10h and calcined at 850℃ for 4h to obtain the modified composite oxide support A'.

[0097] The support A' contains 14.9 wt% TiO2, 84.3 wt% Al2O3, and 0.8 wt% SiO2. The specific surface area of ​​the support is 78 m². 2 / g, pore volume 0.45mL / g, crushing strength 196N / cm. The results are shown in Table 1.

[0098] Preparation Example 2

[0099] The selected material is a TiO2-Al2O3 composite oxide produced by Yantai Heng Hui Chemical Co., Ltd., containing 25wt% TiO2 and 75wt% Al2O3, with a specific surface area of ​​62m². 2 / g, pore volume 0.51mL / g.

[0100] 100g of TiO2-Al2O3 composite oxide was impregnated with 1L of a 5wt% hexadecyltrimethylammonium chloride methanol solution for 2h and then dried at 80℃ for 10h. 100g of a 5wt% triethoxysilane aqueous solution was then added dropwise to the dried composite oxide. After the addition was completed, the resulting mixture was stirred uniformly for 20 minutes. The mixture was then dried at 80℃ for 8h and calcined at 900℃ for 3h to obtain the modified composite oxide support B'.

[0101] The support contains 24.5 wt% TiO2, 73.5 wt% Al2O3, and 2.0 wt% SiO2. The specific surface area of ​​the support is 66 μm. 2 / g, pore volume is 0.41mL / g, and crushing strength is 220N / cm. The results are shown in Table 1.

[0102] Preparation Example 3

[0103] The selected material is a TiO2-Al2O3 composite oxide produced by Yantai Heng Hui Chemical Co., Ltd., containing 12wt% TiO2, 88wt% Al2O3, and a specific surface area of ​​66 μm. 2 / g, pore volume is 0.52mL / g.

[0104] 100g of TiO2-Al2O3 composite oxide was impregnated with 1L of a 5wt% tetradecyl dimethyl benzyl ammonium chloride methanol solution for 2h, and then dried at 90℃ for 9h. 100g of a 2.5wt% methyltriethoxysilane aqueous solution was added dropwise to the dried composite oxide. After the addition was completed, the resulting mixture was stirred evenly for 15 minutes. The composite oxide treated in this way was then dried at 90℃ for 9h and calcined at 750℃ for 6h to obtain the modified composite oxide support C'.

[0105] The support contains 11.9 wt% TiO2, 87.1 wt% Al2O3, and 1.0 wt% SiO2. The specific surface area of ​​the support is 72 μm. 2 / g, pore volume of 0.43mL / g, and crushing strength of 205N / cm. The results are shown in Table 1.

[0106] Preparation Example 4

[0107] The TiO2-Al2O3 composite oxide (TiO2 content 18wt%, Al2O3 content 82wt%, specific surface area 67m) produced by Yantai Heng Hui Chemical Co., Ltd. was selected. 2 / g, pore volume of 0.49mL / g), 100g of TiO2-Al2O3 composite oxide was impregnated with 1L of 5wt% dodecyl dimethyl benzyl ammonium chloride methanol solution for 2h, and then dried at 70℃ for 10h. 100g of 8wt% vinyltrimethoxysilane aqueous solution was added dropwise to the dried composite oxide. After the addition was completed, the resulting mixture was stirred evenly for 30 minutes. The composite oxide treated in this way was then dried at 150℃ for 5h and calcined at 650℃ for 6h to obtain the modified composite oxide support D'.

[0108] The support contains 17.5 wt% TiO2, 79.4 wt% Al2O3, and 3.1 wt% SiO2. The specific surface area of ​​the support is 88 μm. 2 / g, pore volume is 0.44mL / g, and crushing strength is 243N / cm. The results are shown in Table 1.

[0109] Preparation Example 5

[0110] The TiO2-Al2O3 composite oxide (TiO2 content 15wt%, Al2O3 content 85wt%, specific surface area 60m²) produced by Yantai Heng Hui Chemical Co., Ltd. was selected.2 / g, pore volume 0.55mL / g, crushing strength 160N / cm), 100g of TiO2-Al2O3 composite oxide was impregnated with 1L of 5wt% hexadecyltrimethylammonium chloride methanol solution for 2h, and then dried at 60℃ for 12h. 100g of 1wt% vinyltrimethoxysilane aqueous solution was added dropwise to the dried composite oxide. After the addition was completed, the resulting mixture was stirred evenly for 20 minutes. The composite oxide treated in this way was then dried at 60℃ for 12h and calcined at 850℃ for 4h to obtain the modified composite oxide support E'.

[0111] The support contains 14.9 wt% TiO2, 84.7 wt% Al2O3, and 0.4 wt% SiO2. The specific surface area of ​​the support is 77 μm. 2 / g, pore volume 0.47mL / g, crushing strength 186N / cm. The results are shown in Table 1.

[0112] Preparation Example 6

[0113] The TiO2-Al2O3 composite oxide (TiO2 content 8wt%, Al2O3 content 92wt%, specific surface area 63m) produced by Yantai Heng Hui Chemical Co., Ltd. was selected. 2 / g, pore volume of 0.54mL / g), 100g of TiO2-Al2O3 composite oxide was impregnated with 1L of 5wt% octadecyl dimethyl benzyl ammonium chloride methanol solution for 2h, and then dried at 110℃ for 7h. 100g of 0.5wt% vinyltrimethoxysilane aqueous solution was added dropwise to the dried composite oxide. After the addition was completed, the resulting mixture was stirred evenly for 10 minutes. The composite oxide treated in this way was then dried at 110℃ for 7h and calcined at 850℃ for 4h to obtain the modified composite oxide support F'.

[0114] The support contains 8.0 wt% TiO2, 91.8 wt% Al2O3, and 0.2 wt% SiO2. The specific surface area of ​​the support is 88 μm. 2 / g, pore volume is 0.44mL / g, and crushing strength is 243N / cm. The results are shown in Table 1.

[0115] Comparative Preparation Example 1

[0116] The TiO2-Al2O3 carrier (TiO2 content 15wt%, Al2O3 content 85wt%, specific surface area 60m²) produced by Yantai Heng Hui Chemical Co., Ltd. was selected. 2 The material (g, pore volume 0.55 mL / g, crushing strength 160 N / cm) was not modified and was denoted as carrier G'. The results are shown in Table 1.

[0117] Comparative Preparation Example 2

[0118] γ-Al2O3 support (specific surface area 140m²) produced by Yantai Heng Hui Chemical Co., Ltd. was selected. 2 The material (with a pore volume of 0.65 mL / g and a crushing strength of 300 N / cm) was not modified and was denoted as carrier H'. The results are shown in Table 1.

[0119] Comparative preparation example 3

[0120] The TiO2-Al2O3 composite oxide (TiO2 content 15wt%, Al2O3 content 85wt%, specific surface area 60m²) produced by Yantai Heng Hui Chemical Co., Ltd. was selected. 2 / g, pore volume 0.55mL / g, crushing strength 160N / cm) 100g, 2wt% vinyltrimethoxysilane aqueous solution 100g was added dropwise to the composite oxide. After the addition was completed, the resulting mixture was stirred evenly for 10 minutes. The composite oxide treated in this way was then dried at 70℃ for 10h and calcined at 850℃ for 4h to obtain modified composite oxide carrier I'.

[0121] The support contains 15.0 wt% TiO2, 84.6 wt% Al2O3, and 0.4 wt% SiO2. The specific surface area of ​​the support is 75 μm. 2 / g, pore volume 0.40mL / g, crushing strength 178N / cm. The results are shown in Table 1.

[0122] Comparative preparation example 4

[0123] The TiO2-Al2O3 composite oxide (TiO2 content 15wt%, Al2O3 content 85wt%, specific surface area 60m²) produced by Yantai Heng Hui Chemical Co., Ltd. was selected. 2 / g, pore volume 0.55mL / g, crushing strength 160N / cm), 100g of TiO2-Al2O3 composite oxide was impregnated with 1L of 5wt% dimethyl dioctadecyl ammonium chloride methanol solution. After impregnation for 2h, it was dried at 70℃ for 10h and calcined at 850℃ for 4h to obtain the modified composite oxide carrier J'.

[0124] The support contains 15 wt% TiO2 and 85 wt% Al2O3. The specific surface area of ​​the support is 81 μm. 2 / g, pore volume is 0.49mL / g, and crushing strength is 168N / cm. The results are shown in Table 1.

[0125] Table 1

[0126]

[0127]

[0128] As shown in Table 1, the modified composite oxide provided by the present invention overcomes the disadvantage of low crushing strength caused by the introduction of TiO2 in metal composite oxides through modification, and significantly improves the crushing strength of the modified composite oxide.

[0129] Example 1

[0130] 95.7 g of the modified composite oxide carrier A' prepared in Preparation Example 1 was added to 500 mL of 0.11 mol / L calcium nitrate solution, impregnated at 25 °C for 4 h, dried at 110 °C for 8 h, and then calcined at 550 °C for 6 h; the calcined composite oxide was then added to 100 mL of 0.13 mol / L copper nitrate solution, impregnated at 25 °C for 4 h, dried at 110 °C for 12 h, and then calcined at 550 °C for 6 h; of course, in other embodiments, the carrier impregnation can be as in this embodiment, where the calcium salt solution and copper salt solution can be impregnated separately, or a mixed solution of calcium salt and copper salt can be formed before impregnating the carrier.

[0131] The calcined composite oxide was immersed in 20 mL of a 0.12 mol / L palladium nitrate solution at 25 °C for 4 h, dried at 110 °C for 12 h, and then calcined at 550 °C for 6 h under a nitrogen atmosphere. This yielded a supported catalyst Pd-Cu-Ca / SiO2-TiO2-Al2O3 (supported catalyst A).

[0132] Example 2

[0133] 94.4 g of the modified composite oxide support B' prepared in Preparation Example 2 was added to 500 mL of 0.12 mol / L calcium nitrate solution, impregnated at 25 °C for 4 h, dried at 110 °C for 8 h, and then calcined at 550 °C for 6 h; the calcined composite oxide was then added to 100 mL of 0.25 mol / L copper nitrate solution, impregnated at 25 °C for 4 h, dried at 110 °C for 12 h, and then calcined at 550 °C for 6 h.

[0134] The calcined composite oxide was immersed in 20 mL of a 0.04 mol / L palladium nitrate solution at 25 °C for 4 h, dried at 110 °C for 12 h, and then calcined at 550 °C for 6 h under a nitrogen atmosphere. This yielded a supported catalyst Pd-Cu-Ca / SiO2-TiO2-Al2O3 (supported catalyst B).

[0135] Example 3

[0136] 0.5 g of the modified composite oxide support C'9 prepared in Preparation Example 3 was added to 500 mL of 0.18 mol / L calcium nitrate solution, impregnated at 25 °C for 4 h, dried at 110 °C for 8 h, and then calcined at 550 °C for 6 h; the calcined composite oxide was then added to 100 mL of 0.50 mol / L copper nitrate solution, impregnated at 25 °C for 4 h, dried at 110 °C for 12 h, and then calcined at 550 °C for 6 h.

[0137] The calcined composite oxide was immersed in 20 mL of a 0.20 mol / L palladium nitrate solution at 25 °C for 4 h, dried at 110 °C for 12 h, and then calcined at 550 °C for 6 h under a nitrogen atmosphere. This yielded a supported catalyst Pd-Cu-Ca / SiO2-TiO2-Al2O3 (supported catalyst C).

[0138] Example 4

[0139] 95.7 g of the modified composite oxide support D' prepared in Preparation Example 4 was added to 500 mL of 0.11 mol / L calcium nitrate solution, impregnated at 25 °C for 4 h, dried at 110 °C for 8 h, and then calcined at 550 °C for 6 h; the calcined composite oxide was then added to 100 mL of 0.25 mol / L copper nitrate solution, impregnated at 25 °C for 4 h, dried at 110 °C for 12 h, and then calcined at 550 °C for 6 h.

[0140] The calcined composite oxide was immersed in 20 mL of a 0.12 mol / L palladium nitrate solution at 25 °C for 4 h, dried at 110 °C for 12 h, and then calcined at 550 °C for 6 h under a nitrogen atmosphere. This yielded a supported catalyst Pd-Cu-Ca / SiO2-TiO2-Al2O3 (supported catalyst D).

[0141] Example 5

[0142] Take 94.3 g of the modified composite oxide support E' prepared in Preparation Example 5 and put it into 500 mL of 0.12 mol / L calcium nitrate solution. Impregnate at 25 °C for 4 h, dry at 110 °C for 8 h, and then calcine at 550 °C for 6 h. Put the calcined composite oxide into 100 mL of 0.25 mol / L copper nitrate solution, impregnate at 25 °C for 4 h, dry at 110 °C for 12 h, and then calcine at 550 °C for 6 h.

[0143] The calcined composite oxide was immersed in 20 mL of a 0.08 mol / L palladium nitrate solution at 25 °C for 4 h, dried at 110 °C for 12 h, and then calcined at 550 °C for 6 h under a nitrogen atmosphere. This yielded a supported catalyst Pd-Cu-Ca / SiO2-TiO2-Al2O3 (supported catalyst E).

[0144] Example 6

[0145] 90.7 g of the modified composite oxide support F' prepared in Preparation Example 6 was added to 500 mL of 0.18 mol / L calcium nitrate solution, impregnated at 25 °C for 4 h, dried at 110 °C for 8 h, and then calcined at 550 °C for 6 h; the calcined composite oxide was then added to 100 mL of 0.50 mol / L copper nitrate solution, impregnated at 25 °C for 4 h, dried at 110 °C for 12 h, and then calcined at 550 °C for 6 h.

[0146] The calcined composite oxide was immersed in 20 mL of a 0.12 mol / L palladium nitrate solution at 25 °C for 4 h, dried at 110 °C for 12 h, and then calcined at 550 °C for 6 h under a nitrogen atmosphere. This yielded a supported catalyst Pd-Cu-Ca / SiO2-TiO2-Al2O3 (supported catalyst F).

[0147] Comparative Example 1

[0148] 0.7 g of the modified composite oxide support G' prepared in Comparative Preparation Example 1 was added to 500 mL of 0.18 mol / L calcium nitrate solution, impregnated at 25 °C for 4 h, dried at 110 °C for 8 h, and then calcined at 550 °C for 6 h; the calcined composite oxide was then added to 100 mL of 0.50 mol / L copper nitrate solution, impregnated at 25 °C for 4 h, dried at 110 °C for 12 h, and then calcined at 550 °C for 6 h.

[0149] The calcined composite oxide was immersed in 20 mL of a 0.12 mol / L palladium nitrate solution at 25 °C for 4 h, dried at 110 °C for 12 h, and then calcined at 550 °C for 6 h under a nitrogen atmosphere. This yielded the supported catalyst Pd-Cu-Ca / TiO2-Al2O3 (supported catalyst G).

[0150] Comparative Example 2

[0151] 0.7 g of the modified composite oxide support H' prepared in Comparative Preparation Example 2 was added to 500 mL of 0.18 mol / L calcium nitrate solution, impregnated at 25 °C for 4 h, dried at 110 °C for 8 h, and then calcined at 550 °C for 6 h; the calcined composite oxide was then added to 100 mL of 0.50 mol / L copper nitrate solution, impregnated at 25 °C for 4 h, dried at 110 °C for 12 h, and then calcined at 550 °C for 6 h.

[0152] The calcined composite oxide was immersed in 20 mL of a 0.12 mol / L palladium nitrate solution at 25 °C for 4 h, dried at 110 °C for 12 h, and then calcined at 550 °C for 6 h under a nitrogen atmosphere. This yielded the supported catalyst Pd-Cu-Ca / γ-Al₂O₃ (supported catalyst H).

[0153] Comparative Example 3

[0154] 90.7 g of the modified composite oxide support I' prepared in Comparative Preparation Example 3 was added to 500 mL of 0.18 mol / L calcium nitrate solution, impregnated at 25 °C for 4 h, dried at 110 °C for 8 h, and then calcined at 550 °C for 6 h; the calcined composite oxide was then added to 100 mL of 0.50 mol / L copper nitrate solution, impregnated at 25 °C for 4 h, dried at 110 °C for 12 h, and then calcined at 550 °C for 6 h.

[0155] The calcined composite oxide was immersed in 20 mL of a 0.12 mol / L palladium nitrate solution at 25 °C for 4 h, dried at 110 °C for 12 h, and then calcined at 550 °C for 6 h under a nitrogen atmosphere. This yielded a supported catalyst Pd-Cu-Ca / SiO2-TiO2-Al2O3 (supported catalyst I).

[0156] Comparative Example 4

[0157] 0.7 g of the modified composite oxide support J' prepared in Comparative Preparation Example 4 was added to 500 mL of 0.18 mol / L calcium nitrate solution, impregnated at 25 °C for 4 h, dried at 110 °C for 8 h, and then calcined at 550 °C for 6 h; the calcined composite oxide was added to 100 mL of 0.50 mol / L copper nitrate solution, impregnated at 25 °C for 4 h, dried at 110 °C for 12 h, and then calcined at 550 °C for 6 h.

[0158] The calcined composite oxide was immersed in 20 mL of a 0.12 mol / L palladium nitrate solution at 25 °C for 4 h, dried at 110 °C for 12 h, and then calcined at 550 °C for 6 h under a nitrogen atmosphere. Supported catalysts Pd-Cu-Ca / TiO2-Al2O3 (supported catalyst J) with different active component contents were obtained.

[0159] The active component content of the catalysts prepared in each embodiment and comparative example is shown in Table 2 (based on 100 parts by mass of the catalyst).

[0160] Table 2 Content of active components in different catalysts

[0161] Carrier Catalyst No. Pd, parts Cu, parts Ca, parts A’ A 0.3 1 3 B’ B 0.1 2 3.5 C’ C 0.5 4 5 D’ D 0.3 1 3 E’ E 0.2 2 3.5 F’ F 0.3 4 5 G’ G 0.3 4 5 H’ H 0.3 4 5 I’ I 0.3 4 5 J’ J 0.3 4 5

[0162] Application Example 1

[0163] Catalyst AJ was applied to the C3 fraction hydrogenation reaction. The composition of the raw materials during the reaction is shown in Table 3. A fixed-bed pilot-scale evaluation device from Tuochuan Scientific Equipment Co., Ltd. was used, with 50 mL of catalyst loaded, to conduct the selective hydrogenation reaction of the C3 fraction.

[0164] Before selecting the hydrogenation reaction, the catalyst is first activated and reduced by using hydrogen gas to activate the catalyst at an activation temperature of 550℃, an activation pressure of 2.0MPa, a hydrogen flow rate of 10mL / min·g relative to the catalyst, and an activation time of 6h.

[0165] The selected reaction conditions for the hydrogenation reaction include: reactor inlet temperature of 25℃, reaction pressure of 0.7MPa, molar ratio of hydrogen to (alkyne + diene) of 1.5:1, recycle ratio of 20:1, hydrogen flow rate of 40mL / h, and feed rate of 25mL / h.

[0166] Table 3. Composition of feedstocks for selective hydrogenation reaction of C3 fraction.

[0167] No. Component Content, wt% 1 propane C3H8 2.94 2 propylene C3H6 92.65 3 Propyne MA 2.23 4 Propadiene PD 2.18

[0168] The catalysts were evaluated under the same conditions as above, and the results of selective hydrogenation are shown in Table 4.

[0169] During the experiment, the content of each component was tested using a chromatograph. The calculation methods for MAPD conversion and propylene selectivity are as follows:

[0170] MAPD conversion rate = (MAPD in feed - MAPD in product) / (MAPD in feed)

[0171] Propylene selectivity = (propylene in product - propylene in feedstock) / (MAPD in feedstock - MAPD in product).

[0172] Table 4 shows the results of selective hydrogenation of the C3 fraction for catalyst AJ.

[0173]

[0174] In summary, when the catalyst of this invention is applied to the selective hydrogenation process of C3 fraction, the MAPD conversion rate can reach over 99%, and the propylene selectivity can reach over 93%.

[0175] The above description of the embodiments is provided to enable those skilled in the art to understand and apply the present invention. It will be apparent to those skilled in the art that various modifications can be easily made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the embodiments described herein, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A selective hydrogenation catalyst for C3 fractions, characterized in that, Includes the carrier and the active components loaded on the carrier. The carrier is a metal composite oxide modified with organic cationic quaternary ammonium salt and silane reagents; the metal composite oxide contains metal element I, which includes aluminum and titanium; The active component contains metal element II, which includes the main active component Pd and optional auxiliary active components. The auxiliary active components include transition metals and / or alkaline earth metals. The transition metals are selected from one or more of Cu, Mn, Ni, and Zn, and the alkaline earth metals are selected from one or more of Ca, Mg, and Ba.

2. The catalyst according to claim 1, characterized in that, The organic cationic quaternary ammonium salt includes a hydrocarbon-based quaternary ammonium salt, preferably, the hydrocarbon-based quaternary ammonium salt has the general formula R4N. + X - , where X - Selected from halide ions and acid radical ions, preferably, the halide ions include F. - Cl - ,Br - and I - The acid radical ions include nitrate ions and carboxylate ions, with the general formula R4N. + X - Each R in the R may be the same or different, and each is independently selected from alkyl, cycloalkyl, aryl, aralkyl and alkylaryl, with at least one R, preferably 1 to 2 Rs selected from alkyl groups of C6 or above, preferably from C6 to C20 alkyl groups, and the remaining Rs are preferably selected from C1 to C4 alkyl groups and C7 to C11 aralkyl groups; Preferably, the organic cationic quaternary ammonium salt includes at least one of bis(octadecyldimethyl)quaternary ammonium salt, hexadecyltrimethyl)quaternary ammonium salt, and C12-18 alkyldimethylbenzyl)quaternary ammonium salt; More preferably, the organic cationic quaternary ammonium salt is selected from at least one of dioctadecyl dimethyl ammonium chloride, hexadecyl trimethyl ammonium chloride, hexadecyl trimethyl ammonium bromide, dodecyl dimethyl benzyl ammonium chloride, tetradecyl dimethyl benzyl ammonium chloride, hexadecyl dimethyl benzyl ammonium chloride, and octadecyl dimethyl benzyl ammonium chloride; and / or The general formula of the silane reagent is SiR 1 x (OR 2 ) y Where x and y are each independently selected from integers from 1 to 3, x + y = 4, R 1 Selected from hydrogen, C1-C6 alkyl and C2-C6 alkenyl, R 2 Selected from C1 to C6 alkyl groups; Preferably, the silane reagent comprises at least one of triethoxysilane, trimethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane; and / or The amount of the organic cationic quaternary ammonium salt is 1%-50% of the mass of the metal composite oxide, preferably 30%-50%, more preferably 35%-50%; and / or The amount of the silane reagent used is 0.5%-30% of the mass of the metal composite oxide, preferably 0.5%-15%, and more preferably 0.5%-10%.

3. The catalyst according to claim 1 or 2, characterized in that, The support is a SiO2-TiO2-Al2O3 composite oxide. Preferably, based on the support, the content of Ti (calculated as TiO2) in the support is 5wt% to 25wt%, the content of Al (calculated as Al2O3) is 65wt% to 90wt%, preferably 80wt% to 90wt%, and the content of Si (calculated as SiO2) is 0.5wt% to 15wt%; and / or The metal composite oxide is an Al2O3-TiO2 composite oxide; preferably, based on the metal composite oxide, the content of Ti in the metal composite oxide, calculated as TiO2, is 5-30 wt%, more preferably 8 wt%-25 wt%; the content of Al in the metal composite oxide, calculated as Al2O3, is 70 wt%-95 wt%, more preferably 75 wt%-92 wt%; and / or The specific surface area of ​​the carrier is 30–150 μm. 2 / g, preferably 50-90m 2 / g; and / or The pore volume of the carrier is 0.2 to 0.8 mL / g, preferably 0.3 to 0.5 mL / g.

4. The catalyst according to any one of claims 1-3, characterized in that, Based on 100 parts by mass of the catalyst, the content of the noble metal, calculated as oxide, is 0.1 to 0.5 parts; and / or, the content of the transition metal, calculated as oxide, is 1 to 5 parts; and / or, the content of the alkaline earth metal, calculated as oxide, is 1 to 5 parts, preferably 3 to 5 parts; and / or The active component is distributed on the support in the form of nanoclusters, wherein the particle size of the nanoclusters is less than 5 nm; and / or The catalyst is activated with hydrogen before use. Preferably, the activation conditions include: activation temperature of 300-600℃, activation pressure of 0-3.0MPa, hydrogen flow rate relative to catalyst of 1mL / min·g-15mL / min·g, and activation time of 6h-18h.

5. The catalyst according to any one of claims 1-4, characterized in that, The preparation of the carrier includes the following steps: The metal composite oxide was first treated with an organic cationic quaternary ammonium salt solution, and then treated with a silane reagent to obtain the carrier. Preferably, the first treatment includes a first impregnation and a first drying performed sequentially; and / or, the second treatment includes adding a solution of a silane reagent dropwise to the first-treated metal composite oxide, followed by stirring, a second drying, and a first calcination, preferably with a stirring time of 1 min to 60 min; Preferably, the solvent of the organic cationic quaternary ammonium salt solution is at least one selected from water, methanol, ethanol, benzene, toluene, chloroethane, isopropanol, acetone, hydrochloric acid, sulfuric acid, nitric acid, sodium hydroxide, and potassium hydroxide. Preferably, the concentration of the organic cation quaternary ammonium salt solution is 0.1 wt% to 10 wt%, more preferably 0.2 to 10 wt%, and even more preferably 1 to 5 wt%. Preferably, the solution of the silane reagent is an aqueous solution of the silane reagent with a concentration of 0.1-10 wt%, more preferably 1-10 wt%. Preferably, the conditions for the first impregnation include: an impregnation temperature of 10°C to 50°C and an impregnation time of 1 hour to 12 hours, preferably 1 hour to 8 hours; Preferably, the conditions for the first and second drying are the same or different, and each independently includes: a drying temperature of 60℃~150℃, preferably 60℃~110℃, and a drying time of 4h~12h; and / or The conditions for the first roasting include: a roasting temperature of 300–1100℃, preferably 500–900℃, and a roasting time of 4–12 hours.

6. A method for preparing a C3 fraction selective hydrogenation catalyst according to any one of claims 1-5, characterized in that, Includes the following steps: S1. The support is impregnated with a solution containing optional active components in the second stage, followed by a third drying and a second calcination to obtain the catalyst precursor; S2. The catalyst precursor is impregnated with a solution containing the main active component in the third stage, followed by a fourth stage of drying and a third stage of calcination to obtain the catalyst.

7. The preparation method according to claim 6, characterized in that, The conditions for the second and third impregnations may be the same or different, and each independently includes: Temperature 20℃~70℃, preferably 20℃~40℃, time 1h~12h, preferably 1~4h; and / or The conditions for the third and fourth drying processes may be the same or different, and each independently includes: a temperature of 60–150°C, preferably 100–150°C, and a time of 1–8 hours, preferably 4–8 hours; and / or The conditions for the second and third roastings may be the same or different, and each independently includes: a temperature of 300–600°C, preferably 400–500°C, a time of 4–12 h, and / or, a roasting atmosphere of air and / or nitrogen.

8. The preparation method according to claim 6 or 7, characterized in that, The volume of the solution containing the co-active component is 0.8 to 2.5 times the pore volume of the carrier; and / or The concentration of the alkaline earth metal solution is 0.1–0.6 mol / L, preferably 0.5–2.5 mol / L; and / or The concentration of the transition metal-containing solution is 0.1–1.5 mol / L; and / or The concentration of the solution containing the main active component is 0.01–0.3 mol / L, preferably 0.01–0.15 mol / L; and / or The solution containing the active ingredient is a hydrochloride solution, a sulfate solution, or a nitrate solution; and / or The solution containing the main active component is a hydrochloride solution, a sulfate solution, or a nitrate solution; and / or The solvents of the solution containing the auxiliary active component and the solution containing the main active component may be the same or different, and each independently includes at least one of water, hydrochloric acid, sulfuric acid, nitric acid, methanol and ethanol.

9. The application of the hydrogenation catalyst according to any one of claims 1-5 or the hydrogenation catalyst prepared by any one of claims 6-8 in the selective hydrogenation of C3 fraction to propylene; Preferably, the C3 fraction includes propylene and propane; Preferably, the C3 fraction contains impurities, which are propyne and / or propylene; Preferably, the C3 fraction comprises the following components: 80 wt% to 99.99 wt% propylene, and / or 0 wt% to 19.99 wt% propane, and / or 0.01 wt% to 5 wt% propyne, and / or 0 wt% to 5% propadiene; Preferably, the conditions for the hydrogenation reaction include: A fixed-bed reactor was used, with an inlet temperature of 20–50℃, a hydrogen to (alkyne + diene) molar ratio of 1–2.5:1, a pressure of 0.5–0.8 MPa, a recycle ratio of 10–30:1, and a volumetric hourly space velocity of 1–3 h⁻¹. -1 .

10. A method for selective hydrogenation of a C3 fraction to produce propylene, characterized in that, include: Propylene and propadiene in the C3 fraction undergo selective hydrogenation with hydrogen in the presence of the C3 fraction selective hydrogenation catalyst according to any one of claims 1-5 or the C3 fraction selective hydrogenation catalyst prepared by the preparation method according to any one of claims 6-8 to produce propylene. Preferably, the hydrogenation catalyst is first activated and reduced. Preferably, the activation and reduction conditions include: activation and reduction using hydrogen gas, with a hydrogen flow rate of 1-15 mL / min·g relative to the catalyst, an activation temperature of 300-600℃, an activation pressure of 0-3.0 MPa, and an activation time of 6-18 h. Preferably, the conditions for selecting the hydrogenation reaction include: using a fixed-bed reactor, a reactor inlet temperature of 20–50°C, a hydrogen to (alkyne + diene) molar ratio of 1–2.5:1, a pressure of 0.5–0.8 MPa, a recycle ratio of 10–30:1, and a volume hourly space velocity of 1–3 h⁻¹. -1 ; Preferably, the C3 fraction contains impurities, which are propyne and / or propylene. Preferably, the C3 fraction comprises the following components: 80 wt% to 99.99 wt% propylene, and / or 0 wt% to 19.99 wt% propane, and / or 0.01 wt% to 5 wt% propyne, and / or 0 wt% to 5% propadiene.

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