Catalyst, preparation method and application of catalyst in selective hydrogenation of C3 fraction

Abstract

The invention provides a catalyst, a preparation method and application of the catalyst in selective hydrogenation of C3 fractions. The invention provides a catalyst which comprises a carrier and an active component, the carrier is a metal composite oxide, the metal composite oxide contains a metal element I, and the metal element I comprises aluminum and titanium; the active component contains a metal element II, and the metal element II comprises Pd, Cu and Mn. The prepared catalyst has a specific structure, TiO2 is uniformly dispersed on the surface of Al2O3, and compared with similar catalysts, the selective hydrogenation catalyst has the characteristics of high alkyne saturation activity, good selectivity, high low-temperature activity, good impurity poisoning resistance, good raw material adaptability and the like.

Description

Technical Field

[0001] The invention relates to the technical field of selective hydrogenation of carbon three fractions, and in particular to a catalyst, a preparation method and application thereof in the selective hydrogenation of carbon three fractions. Background Art

[0002] Propylene is an important basic chemical raw material that can be used to produce polypropylene, acrylonitrile, propylene oxide, acrolein, acrylic acid, etc. Its downstream products are widely used in films, fibers, rubber, resins, coatings and other fields.

[0003] Propylene is usually obtained in petroleum cracking ethylene production units. The C3 fraction in the cracking gas usually 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, to obtain high-purity propylene, MAPD must be removed first. Usually, MAPD in the C3 fraction is selectively hydrogenated to generate propylene, and there will also be certain side reactions to generate propane.

[0004] MAPD in the C3 fraction easily polymerizes into colloid at high temperature and precipitates on the catalyst surface, which quickly deactivates the catalyst and causes the catalyst to be frequently activated and regenerated. Therefore, it is hoped that the hydrogenation catalyst has a higher low-temperature activity and maintains an appropriate colloid capacity so that the activity of the polymer on the catalyst surface remains unchanged before being washed, thereby extending the service life of the catalyst, which is very important in industrial production.

[0005] Industrial devices for removing MAPD from C3 fractions mainly include gas phase catalytic selective hydrogenation, liquid phase catalytic selective hydrogenation and catalytic distillation. At present, the liquid phase selective hydrogenation method is generally used in the market. This method has a simple process flow, low reaction temperature, low energy consumption, safety, environmental protection and easy operation. The selective hydrogenation of C3 fractions has high requirements for the selection of catalysts and the control of the reaction process. At present, the industrial C3 fraction selective hydrogenation catalyst is a loaded catalyst with precious metal palladium as the main active component and alumina as the carrier. Some also add additives such as silver, gold, and copper to improve propylene selectivity.

[0006] However, the industrial C3 fraction selective hydrogenation catalysts in the prior art still have problems such as low activity, poor stability and low selectivity for propylene. Summary of the invention

[0007] In order to solve the above problems in the prior art, the present invention provides a catalyst, a preparation method and application thereof in the selective hydrogenation of a C3 fraction.

[0008] In a first aspect, the present invention provides a catalyst, wherein the carrier is a metal composite oxide, the metal composite oxide contains a metal element I, and the metal element I includes aluminum and titanium;

[0009] The active component contains metal element II, and the metal element II includes Pd, Cu and Mn.

[0010] As a specific embodiment of the present invention, the metal composite oxide is Al 2 O 3 -TiO 2 Composite oxides.

[0011] As a specific embodiment of the present invention, the metal composite oxide TiO 2 The content of the metal composite oxide is 5wt% to 20wt%.

[0012] Preferably, the metal composite oxide contains TiO 2 The content is 9wt% to 20wt% of the carrier.

[0013] As a specific embodiment of the present invention, the content of Pd is 0.1 wt% to 0.5 wt% of the catalyst, preferably 0.1 wt% to 0.3 wt% calculated as the amount of Pd oxide.

[0014] As a specific embodiment of the present invention, the content of Cu is 1 wt% to 5 wt% of the catalyst, preferably 2 wt% to 4 wt%, calculated as the amount of Cu oxide.

[0015] As a specific embodiment of the present invention, the content of Mn is 5 wt% to 20 wt% of the catalyst, preferably 10 wt% to 15 wt%, calculated as the amount of Mn oxide.

[0016] As a specific embodiment of the present invention, the specific surface area of ​​the metal composite oxide is 50 to 120 m 2 / g.

[0017] Preferably, the specific surface area of ​​the metal composite oxide is 70 to 100 m 2 / g.

[0018] As a specific embodiment of the present invention, the pore volume of the metal composite oxide is 0.4 to 1.5 mL / g.

[0019] Preferably, the pore volume of the metal composite oxide is 0.6 to 1.2 mL / g.

[0020] As a specific embodiment of the present invention, the most probable pore size of the metal composite oxide is

[0021] Preferably, the most probable pore size of the metal composite oxide is

[0022] In a second aspect, the present invention provides a method for preparing a catalyst, comprising the following steps:

[0023] Step 1: providing a mixed solution containing an aluminum salt solution and a titanium salt solution, adding an alkali solution to the mixed solution, and allowing the mixed solution to stand to obtain a carrier;

[0024] Step 2: Mix the carrier and the active component salt solution, impregnate, filter and dry I to obtain a precursor, reduce the precursor, dry II and calcine to obtain a catalyst, the active component salt solution includes palladium salt solution, copper salt solution and manganese salt.

[0025] As a specific embodiment of the present invention, the standing conditions in step 1 include: controlling the mixed solution to be an alkaline environment, the temperature to be 65 to 95° C., and the time to be 15 to 60 minutes.

[0026] As a specific implementation of the present invention, an alkaline solution is used to control the pH value of the mixed solution to 8-9.

[0027] As a specific embodiment of the present invention, the concentration of Al in the aluminum salt solution is 0.5 to 2.5 mol / L, and the concentration of Ti in the titanium salt solution is 0.15 to 1.2 mol / L.

[0028] As a specific embodiment of the present invention, the aluminum salt is selected from one or more of aluminum sulfate, aluminum chloride, aluminum nitrate and other organic salts of aluminum;

[0029] As a specific embodiment of the present invention, the titanium salt is selected from one or more soluble acid solutions of metatitanic acid, titanium sulfate, titanium tetrachloride, tetraethyl titanate, etc.

[0030] As a specific embodiment of the present invention, when preparing the catalyst, the water absorption rate of the carrier is first determined. Specifically, an appropriate amount of the carrier (mass is A) is weighed, and an appropriate amount of deionized water is added to soak for 15 to 120 minutes, and excess water is sucked out with filter paper to make the carrier just completely wet, and weighed (mass is B). Calculate the water absorption rate of the carrier = (BA) ÷ (A × 100%).

[0031] As a specific embodiment of the present invention, the volume of the active component metal salt solution is 0.8 to 2.5 times the equivalent volume of the carrier pore volume. The concentrations of the manganese salt, copper salt and palladium salt solutions are prepared according to the water absorption rate of the carrier and the equal volume impregnation method.

[0032] As a specific embodiment of the present invention, the concentration of Mn in the manganese salt solution is 0.5-2.5 mol / L, the concentration of Cu in the copper salt solution is 0.1-1.5 mol / L, and the concentration of Pd in ​​the palladium salt solution is 0.01-0.15 mol / L.

[0033] As a specific embodiment of the present invention, the manganese salt includes one or more of manganese oxalate, manganese acetate, manganese formate and organic acid salts of manganese;

[0034] As a specific embodiment of the present invention, the copper salt includes one or more of copper chloride, copper nitrate, and copper sulfate;

[0035] As a specific embodiment of the present invention, the palladium salt includes one or more of palladium chloride, palladium nitrate, palladium sulfate, sodium tetranitrate palladium and an organic acid salt of palladium.

[0036] As a specific embodiment of the present invention, the mixing conditions of the carrier and the manganese salt solution include: the mixing time is 1 to 4 hours.

[0037] As a specific embodiment of the present invention, the mixing conditions of the carrier and the copper salt solution include: the mixing time is 1 to 4 hours.

[0038] As a specific embodiment of the present invention, the mixing conditions of the carrier and the palladium salt solution include: the mixing time is 1 to 4 hours.

[0039] As a specific embodiment of the present invention, the reduction of the precursor in step 2 includes: reducing the precursor using hydrazine hydrate.

[0040] Preferably, the precursor is immersed in a hydrazine hydrate solution, and the immersion conditions include: a temperature of 10 to 60° C. and a time of 0.1 to 2 hours.

[0041] As a specific embodiment of the present invention, the calcination conditions include: a temperature of 400-600° C., a time of 3-8 hours, and a calcination atmosphere of air or an inert gas, and the specific inert gas is nitrogen.

[0042] As a specific embodiment of the present invention, the conditions of drying I include: temperature of 100 to 150° C. and time of 4 to 20 hours.

[0043] As a specific embodiment of the present invention, the conditions of drying II include: temperature of 100 to 150° C. and time of 4 to 20 hours.

[0044] In a third aspect, the present invention provides a catalyst prepared by the method provided in the second aspect of the present invention.

[0045] In a fourth aspect, the present invention provides use of the catalyst provided in the first aspect of the present invention or the catalyst provided in the third aspect of the present invention in the selective hydrogenation of a C3 fraction, wherein the C3 fraction contains impurities, and the impurities are propyne and propadiene.

[0046] In the present invention, selective hydrogenation refers to the selective hydrogenation reaction of hydrogen with propyne and propadiene to produce propylene.

[0047] As a specific embodiment of the present invention, the C3 fraction includes, by mass, 92 to 96 parts of propylene, 2.9 to 3.5 parts of propane, and 1 to 5 parts of propyne and propadiene.

[0048] In a fifth aspect, the present invention provides a method for selective hydrogenation of a C3 fraction, wherein impurities in the C3 fraction undergo hydrogenation reaction in the presence of the catalyst provided in the first aspect of the present invention or the catalyst provided in the third aspect of the present invention; the impurities include propyne and propadiene.

[0049] As a specific embodiment of the present invention, the reaction conditions include: using a fixed bed reactor, the reactor inlet temperature is 20-50°C, the pressure is 0.5-0.8MPa, the circulation ratio is 10-30:1, and the molar ratio of hydrogen to impurities is 1-2.5:1.

[0050] Further preferably, the reactor inlet temperature is 20-25° C., the pressure is 0.5-0.7 MPa, the circulation ratio is 15-25:1, and the molar ratio of hydrogen to impurities is 1.3-2.1:1.

[0051] Alumina and titanium oxide are commonly used support materials for preparing hydrogenation catalysts. 2 As a carrier alone and traditional Al 2 O 3 Compared with TiO, it has a smaller specific surface area, and the active anatase type is easily converted into an inert rutile structure at high temperature. It has poor mechanical strength and weak acidity, and poor thermal stability. 2 The hydrogenation catalyst developed as a carrier has the characteristics of high activity, good low temperature activity and strong resistance to poisoning. 2 O 3 -TiO 2 As a carrier, the composite oxide not only maintains the advantages of alumina carrier such as high specific surface area, high strength and good thermal stability, but also has the unique properties of titanium oxide. 2 O 3 It will affect the structure and properties of the active phase of the catalyst. Adding Al 2 O 3 The low-temperature activity of the post-catalyst will be improved, and the ideal reaction activity can be achieved at a lower inlet temperature. At the same time, the lower reaction temperature can reduce the rate of alkyne polymerization, thereby greatly reducing the rate of catalyst carbon deposition, thereby improving the catalytic activity and anti-carbon deposition ability of the catalyst.

[0052] The present invention provides a cheap and readily available C3 fraction selective hydrogenation catalyst suitable for industrial production. The catalyst has a specific structure, TiO 2 In Al 2 O 3The catalyst obtained by combining the carrier and the active component with a uniformly dispersed surface has the characteristics of high acetylenic saturation activity, good selectivity, high low-temperature activity, good resistance to impurity poisoning and raw material adaptability compared with similar catalysts. DETAILED DESCRIPTION

[0053] The present invention will be further described below in conjunction with specific embodiments, but they do not constitute any limitation to the present invention.

[0054] TiO 2 The content is determined using a spectrophotometer. The principle used is: in sulfuric acid solution, Ti 4+ It forms a yellow complex with hydrogen peroxide. 2 Titanyl sulfate is generated in hot sulfuric acid, and titanium sulfate reacts with hydrogen peroxide to generate a stable orange-yellow [TiO(H 2 O 2 )] 2- , measured by spectrophotometer at 430nm.

[0055] The specific surface area, pore volume and most probable pore size of the carrier were measured using the ASAP 2020 adsorption instrument (N 2 The specific surface area and pore structure of the catalyst were determined by the adsorption-desorption method. Before the test, the catalyst sample was degassed at 623K for 4h, nitrogen was adsorbed at liquid nitrogen temperature, and the sample data was processed using AMSM software. The specific surface area of ​​the sample was obtained using the Brunauer-Emmet-Teller (BET) method. The average pore size was obtained based on the nitrogen adsorption isotherm curve using the Barrett-Joyner-Halenda (BJH) method, and the pore volume was obtained using the P / Po single-point desorption curve.

[0056] The contents of Pd, Cu and Mn in the catalyst were determined by ICP atomic emission spectrometer, and the test standard was: JYT015 General Rules for Inductively Coupled Plasma Atomic Emission Spectrometry. The instrument used the Optima 8300 full-spectrum direct-reading ICP spectrometer from PerkinElmer (PE) of the United States, with a stepped grating, solid-state detector, dual-path dual solid-state detectors in the ultraviolet and visible regions, and flat-plate plasma technology to ensure the instrument has the lowest argon consumption.

[0057] Example 1

[0058] Preparation of vector

[0059] Prepare 1L of aluminum sulfate deionized water solution with an Al concentration of 0.84mol / L. Prepare 0.5L of titanic acid dilute sulfuric acid solution with a Ti concentration of 0.38mol / L. Prepare NH 4 +0.38 mol / L ammonium bicarbonate solution was mixed with 1.75 mol / L ammonia water to prepare 1L of mixed alkali solution with pH=11-12. 1L of aluminum sulfate deionized water solution, 0.5L of metatitanic acid dilute sulfuric acid solution and mixed alkali solution were co-precipitated in parallel, the solution pH was controlled to 8.5, the temperature was 70°C, and the solution was kept for 40 minutes to obtain a precipitate, that is, Al 2 O 3 -TiO 2 carrier.

[0060] After testing, the TiO 2 The content is 11.87wt%, and the specific surface area is 87m 2 / g, pore volume is 0.53mL / g, and the most probable pore diameter is

[0061] Prepare 150 mL of manganese oxalate aqueous solution with a Mn concentration of 0.83 mol / L; prepare 120 mL of copper sulfate aqueous solution with a Cu concentration of 0.12 mol / L. 2 O 3 -TiO 2 90.8g of carrier, 150mL of manganese oxalate aqueous solution was poured into the prepared carrier for impregnation. The impregnation process included stirring for 20min, standing for 1.5h, draining the water, and drying at 120℃ for 10h. Precipitate 1 was obtained;

[0062] Then, 120 mL of copper sulfate aqueous solution was poured into the precipitate 1, and the precipitate 2 was obtained by the same immersion process as above;

[0063] Prepare 100 mL of a 0.03 mol / L palladium chloride aqueous solution, and then impregnate the above precipitate 2 with 100 mL of the 0.03 mol / L palladium chloride aqueous solution, and follow the above impregnation process to obtain a catalyst precursor.

[0064] The obtained catalyst precursor was reduced with 120 mL of 10 wt% hydrazine hydrate aqueous solution at room temperature for 1 h, then repeatedly rinsed with deionized water, drained, dried at 120° C. for 6 h, and then calcined at 480° C. for 4 h in air atmosphere to obtain Catalyst A.

[0065] The Pd content in Catalyst A is 0.30 wt%, the Cu content is 1 wt%, and the Mn content is 10 wt%.

[0066] Example 2

[0067] Catalyst B was prepared by the same preparation method as in Example 1, except that the content of active metals in Catalyst B was different from that in Example 1. The content of active components in the catalyst is shown in Table 1.

[0068] Example 3

[0069] Catalyst C was prepared by the same preparation method as in Example 1, except that the content of active metals in Catalyst C was different from that in Example 1. The content of active components in the catalyst is shown in Table 1.

[0070] Comparative Example 1

[0071] Prepare 1L of aluminum sulfate deionized water solution with an Al concentration of 0.84mol / L. Prepare 0.5L of dilute sulfuric acid solution of metatitanic acid with a titanium concentration of 0.38mol / L. Prepare NH 4 + A 0.38 mol / L ammonium bicarbonate solution was mixed with 1.75 mol / L ammonia water to prepare 1 L of a mixed alkaline solution with a pH of 11-12.

[0072] At a temperature of 70°C, the above-mentioned 1L aluminum sulfate deionized water solution, 0.5L metatitanic acid dilute sulfuric acid solution, and mixed alkali solution were co-precipitated in parallel. The flow rate of the mixed alkali solution was controlled to keep the pH value of the precipitate in the range of 5.0-6.0 for 8 minutes, and then the flow rate of the mixed alkali solution was increased to keep the pH value of the mixed solution in the range of 8.5-9.5 for 8 minutes, and then the flow rate of the mixed alkali solution was reduced to keep the pH value of the mixed solution in the range of 5.0-6.0 for 8 minutes, and then the flow rate of the mixed alkali solution was increased to keep the pH value of the precipitate in the range of 8.5-9.5, and this was repeated until all the solutions were added. The reaction solution was allowed to stand at 70°C for 30 minutes, filtered, and the precipitate was washed with deionized water 15 times the volume of the precipitate for 30 minutes, then filtered, and then washed. This process was repeated four times, and finally the precipitate was dried at 110°C for 10 hours, and roasted at 950°C for 5 hours. The roasting atmosphere was air to obtain titanium oxide-alumina carrier D. The prepared support contains TiO 2 The content is 10.56wt%.

[0073] Table 1 Catalyst compositions numbered AD

[0074] Catalyst No. Carrier Pd, wt% Cu,wt% Mn, wt% A <![CDATA[Al 2 THE 3 -Uncle 2 ]]> 0.3 1 10 B <![CDATA[Al 2 THE 3 -Uncle 2 ]]> 0.1 2 12 C <![CDATA[Al 2 THE 3 -Uncle 2 ]]> 0.3 4 15 D <![CDATA[Al 2 THE 3 -Uncle 2 ]]> 0 0 0

[0075] Examples 1-3 and Comparative Example 1 were applied to the C3 fraction hydrogenation reaction. The raw material composition during the reaction is shown in Table 2.

[0076] Table 2 Composition of raw materials for selective hydrogenation of C3 fraction

[0077] serial number composition Mass fraction 1 <![CDATA[Propane C 3 H 8 > 3.2 2 <![CDATA[Propylene C 3 H 6 > 92.0 3 Propylene MA 1.6 4 Propylene PD 2.8 5 other 0.2

[0078] The fixed bed test evaluation device of Tuochuan Scientific Research Equipment Co., Ltd. was used, loaded with 50mL of catalyst, to carry out the selective hydrogenation reaction of C3 fraction. Reaction conditions: reactor inlet temperature is 25℃, reaction pressure is 0.5~0.7MPa, circulation ratio is 20:1, hydrogen feed rate is 40mL / h, and impurity feed rate is 25mL / h. Impurities are propyne and propadiene.

[0079] Catalysts A, B, C, and D were evaluated under the same conditions, and the selective hydrogenation results are shown in Table 3.

[0080] During the experiment, a chromatograph was used to test the content of each component. The calculation method of MAPD conversion rate and propylene selectivity is as follows:

[0081] MAPD conversion = (MAPD in feedstock - MAPD in product) / (MAPD in feedstock)

[0082] Propylene selectivity = (propylene in product - propylene in feed) / (MAPD in feed - MAPD in product)

[0083] Table 3 Selective hydrogenation results of C3 fraction in carrier numbered AD

[0084]

[0085] In summary, the catalyst of the present invention is used in the selective hydrogenation process of carbon three fractions, and the MAPD conversion rate can reach more than 99%, and the propylene selectivity can reach more than 92%, which are much higher than the MAPD conversion rate and propylene selectivity of the catalyst prepared in the comparative example. In addition, the carrier preparation process of the present invention is simple and easy to operate compared with the comparative example 1.

[0086] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. A catalyst, characterized in that It includes a carrier and an active ingredient, The carrier is a metal composite oxide, the metal composite oxide contains metal element I, and the metal element I includes aluminum and titanium; The active component contains metal element II, and the metal element II includes Pd, Cu and Mn.

2. The catalyst according to claim 1, characterized in that The metal composite oxide is Al2O3-TiO2 composite oxide; And / or, the content of TiO2 in the metal composite oxide is 5wt% to 20wt% of the metal composite oxide; preferably 9wt% to 20wt%.

3. The catalyst according to claim 1 or 2, characterized in that Calculated as Pd oxide, the Pd content is 0.1wt% to 0.5wt% of the catalyst, preferably 0.1wt% to 0.3wt%; calculated as Cu oxide, the Cu content is 1wt% to 5wt% of the catalyst, preferably 2wt% to 4wt%; calculated as Mn oxide, the Mn content is 5wt% to 20wt% of the catalyst, preferably 10wt% to 15wt%.

4. The catalyst according to any one of claims 1 to 3, characterized in that The specific surface area of ​​the metal composite oxide is 50 to 120 m 2 / g, preferably 70 to 100 m 2 / g; the pore volume of the metal composite oxide is 0.4 to 1.5 mL / g, preferably 0.6 to 1.2 mL / g; the most probable pore size of the metal composite oxide is Preferably 5. A method for preparing a catalyst, characterized in that: The steps include: Step 1: providing a mixed solution containing an aluminum salt solution and a titanium salt solution, adding an alkali solution to the mixed solution, and allowing the mixed solution to stand to obtain a carrier; Step 2: Mix and impregnate the carrier with the active component salt solution, filter and dry I to obtain a precursor, reduce the precursor, dry II, and calcine to obtain a catalyst, wherein the active component salt solution includes a palladium salt solution, a copper salt solution and a manganese salt.

6. The preparation method according to claim 5, characterized in that: The standing conditions in step 1 include: controlling the mixed solution to an alkaline environment, a temperature of 65 to 95° C., and a time of 15 to 60 minutes; Preferably, the pH value of the mixed solution is controlled to be 8-9; and / or the concentration of Al in the aluminum salt is 0.5-2.5 mol / L, and the concentration of Ti in the titanium salt is 0.15-1.2 mol / L.

7. The preparation method according to claim 5 or 6, characterized in that: In step 2, The volume of the active component metal salt solution is 0.8 to 2.5 times the equivalent volume of the carrier pore volume; The concentration of Mn in the manganese salt solution is 0.5-2.5 mol / L, the concentration of Cu in the copper salt solution is 0.1-1.5 mol / L, and the concentration of Pd in ​​the palladium salt solution is 0.01-0.15 mol / L; Preferably, the manganese salt includes one or more of manganese oxalate, manganese acetate, manganese formate and organic acid salts of manganese; Preferably, the copper salt includes one or more of copper chloride, copper nitrate, and copper sulfate; Preferably, the palladium salt includes one or more of palladium chloride, palladium nitrate, palladium sulfate, sodium tetranitrate palladium and an organic acid salt of palladium.

8. The preparation method according to any one of claims 5 to 7, characterized in that: The mixed impregnation conditions of the carrier and the manganese salt solution include: the time is 1 to 4 hours; and / or, the mixed impregnation conditions of the carrier and the copper salt solution include: the time is 1 to 4 hours; and / or, the mixed impregnation conditions of the carrier and the palladium salt solution include: the time is 1 to 4 hours.

9. The preparation method according to any one of claims 5 to 8, characterized in that: The reduction of the precursor in step 2 includes: reducing the precursor with hydrazine hydrate; Preferably, the precursor is immersed in a hydrazine hydrate solution, and the immersion conditions include: a temperature of 10 to 60° C. and a time of 0.1 to 2 h; And / or, the calcination conditions include: a temperature of 400 to 600° C., a time of 3 to 8 hours, and an atmosphere of air and / or an inert gas; And / or, the conditions of drying I include: temperature of 100 to 150° C. and time of 4 to 20 h; And / or, the conditions of drying II include: temperature of 100-150° C. and time of 4-20 h.

10. A catalyst prepared by the preparation method according to any one of claims 5 to 9.

11. Use of the catalyst according to any one of claims 1 to 4 or the catalyst according to claim 10 in the selective hydrogenation of a C3 fraction, wherein the C3 fraction contains impurities, and the impurities are propyne and propadiene.

12. The use according to claim 11, characterized in that: The C3 fraction includes, by mass, 92-96 parts of propylene, 2.9-3.5 parts of propane, and 1-5 parts of propyne and propadiene.

13. A method for selective hydrogenation of a C3 fraction, characterized in that: In the presence of the catalyst according to any one of claims 1 to 4 or the catalyst according to claim 10, a hydrogenation reaction occurs in the impurities in the C3 fraction; the impurities include propyne and propadiene; the reaction conditions include: using a fixed bed reactor, the reactor inlet temperature is 20 to 50° C., the pressure is 0.5 to 0.8 MPa, the circulation ratio is 10 to 30:1, and the molar ratio of hydrogen to impurities is 1 to 2.5:1; Preferably, the reactor inlet temperature is 20-25° C., the pressure is 0.5-0.7 MPa, the circulation ratio is 15-25:1, and the molar ratio of hydrogen to impurities is 1.3-2.1:1.

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