A selective hydrogenation catalyst for cracked gasoline, its preparation method and application

Abstract

This invention provides a selective hydrogenation catalyst for cracked gasoline, its preparation method, and its application. The catalyst comprises an active component, palladium, and a phosphorus-modified alumina-silica support. Based on catalyst weight, the content of the active component, palladium, is 0.10%–0.25%, and the average particle size of palladium is 2–3 nm. When used in the selective hydrogenation of cracked gasoline to remove conjugated dienes, the catalyst of this invention exhibits excellent diene hydrogenation rates. Compared with existing industrial cracked gasoline hydrogenation catalysts, the catalyst of this invention uses a lower palladium content at the same activity, significantly reducing catalyst costs.

Description

Technical Field

[0001] This invention relates to the field of catalytic hydrogenation technology, specifically to a selective hydrogenation catalyst for cracked gasoline, its preparation method, and its application. Background Technology

[0002] Cracked gasoline is a general term for the C5-204℃ fraction produced as a byproduct in the steam cracking of naphtha and gas oil to produce ethylene, accounting for approximately 50-80% of ethylene production. It contains over 200 components, including alkanes, cycloalkanes, dienes, alkenes, cycloalkenes, and alkynes. As a major source of aromatics, cracked gasoline contributes over 40% of global aromatic hydrocarbon production. The process involves first selective hydrogenation to remove dienes and conjugated aromatics, followed by second-stage hydrogenation to saturate monoolefins and remove impurities such as sulfur, nitrogen, and oxygen. Finally, solvent extraction yields the aromatics. The cracked gasoline hydrogenation catalyst plays a crucial role as the core of the hydrogenation technology.

[0003] The primary hydrogenation of cracked gasoline can be divided into central fraction (C6-C8) and full fraction (C5-C9) hydrogenation. During hydrogenation, dienes and alkynes easily polymerize into gums at high temperatures, depositing on the catalyst surface and causing catalyst deactivation, requiring frequent activation and regeneration. The main catalysts for primary hydrogenation of cracked gasoline are palladium-alumina and nickel-alumina catalysts. Palladium-based catalysts have advantages such as low initial temperature, high hydrogenation activity, high space velocity adaptability, and long service life.

[0004] Catalysts for the hydrogenation of cracked gasoline generally involve impregnating a support with a solution of metal salts or organometallic compounds of the active components, and then loading the oxides of the active components onto the surface of the support through processes such as drying and calcination. Before being used in the hydrogenation reaction of cracked gasoline, they need to be reduced by hydrogen gas.

[0005] CN104415797B discloses a selective hydrotreating catalyst for cracked gasoline, comprising a support and an active component loaded on the support, wherein the active component palladium is prepared in a microemulsion system containing an aqueous phase of a polymer and an unassisted surfactant; CN103084171A discloses a method for preparing a Pd-based primary hydrotreating catalyst for cracked gasoline, wherein the catalyst metal active component is prepared by a microemulsion method and then loaded onto a support after reduction; CN101429453B utilizes an alumina support with predominantly θ-type and a mixed θ / α crystal structure, and employs additives... Modification with lanthanum, cerium, and alkaline earth metals yields Pd-based catalysts; CN102728351B discloses a palladium-silver / alumina-titanium oxide catalyst for selective hydrogenation of cracked gasoline or its fractions, the catalyst comprising an alumina-titanium oxide composite as a support, and active components Pd and Ag supported on the support; CN101121899B discloses a method for selective hydrogenation of whole-run cracked gasoline, mainly addressing the technical problem in the prior art of selectively hydrogenating whole-run cracked gasoline with high gum and free water content.

[0006] In existing technologies and industrially applied catalysts, the content of the precious metal palladium is relatively high, resulting in high catalyst costs, and the hydrogenation rate of dienes still needs to be further improved. Summary of the Invention

[0007] To address the issues of high cost and low diene hydrogenation rates in existing selective hydrogenation catalysts for cracked gasoline, this invention provides a novel selective hydrogenation catalyst for cracked gasoline and its preparation method. This catalyst is low-cost and exhibits excellent diene hydrogenation rates in the hydrogenation reaction of cracked gasoline.

[0008] The first aspect of this invention provides a selective hydrogenation catalyst for cracked gasoline, the catalyst comprising an active component palladium and a phosphorus-modified alumina-silica support, wherein the content of the active component palladium is 0.10% to 0.25% based on the weight of the catalyst, and the average particle size of palladium is 2 to 3 nm. Further, preferably, the content of the active component palladium is 0.15% to 0.20% based on the weight of the catalyst.

[0009] Furthermore, based on the weight of the phosphorus-modified alumina-silica carrier, the silica content is 0.01% to 15.00%, preferably 0.05% to 9.00%, and the phosphorus content is 0.2% to 5.0%, preferably 0.2% to 1.0%.

[0010] Furthermore, the phosphorus-modified alumina-silica support has an average pore size of 5–20 nm, preferably 7–15 nm, and a specific surface area of ​​50–200 m². 2 / g, preferably 80-180m 2 / g.

[0011] A second aspect of the present invention provides a method for preparing the above-mentioned selective hydrogenation catalyst for cracked gasoline, comprising:

[0012] (1) Add ammonia water dropwise to chloropalladium acid aqueous solution to prepare dichlorotetraamminepalladium impregnation solution;

[0013] (2) The alumina-silica support was impregnated with phosphoric acid solution and dried to obtain phosphorus-modified alumina-silica support;

[0014] (3) Impregnate the phosphorus-modified alumina-silica support obtained in step (2) with the dichlorotetraamminepalladium impregnation solution obtained in step (1), dry and calcine to obtain the catalyst.

[0015] Furthermore, in step (1), the pH of the dichlorotetraamminepalladium impregnation solution is controlled at 9 to 11.

[0016] Furthermore, in step (1), the palladium content in the chloropalladic acid aqueous solution is 0.02wt% to 0.05wt%.

[0017] Further, in step (2), the impregnation method is equal volume impregnation, and the concentration of phosphoric acid is 0.2wt% to 5.0wt%, preferably 0.3wt% to 3.0wt%.

[0018] Further, in step (2), the drying conditions are: drying temperature of 50-80℃ and drying time of 10-24 hours.

[0019] Furthermore, in step (3), the impregnation method is excessive impregnation, the impregnation process is carried out at a temperature of 50 to 99°C, and the impregnation time is 10 to 40 minutes.

[0020] Further, in step (3), a washing step may be performed before drying, and the washing may use pure water or ultrapure water. The drying conditions are: drying temperature of 100-120℃ and drying time of 60-120 min. The calcination conditions are: calcination temperature of 350-650℃ and calcination time of 2-6 hours, and the calcination atmosphere is an oxygen-containing gas (such as air).

[0021] Furthermore, in step (2), the alumina-silica support can be prepared by any method known to those skilled in the art, such as co-precipitation or mechanical kneading.

[0022] The third aspect of the present invention provides the application of the above-mentioned selective hydrogenation catalyst for cracked gasoline in the hydrogenation reaction of cracked gasoline to remove conjugated dienes.

[0023] Further, the application includes: reacting cracked gasoline with the hydrogenation catalyst in a hydrogen atmosphere, under the following reaction conditions: reaction temperature of 35–100°C, preferably 40–80°C; reaction pressure of 2.0–4.0 MPa, preferably 2.5–3.5 MPa; recycle ratio (recycled fuel / fresh feedstock) of 1.0–5.0; and volume hourly space velocity (VHSV) of the cracked gasoline of 3–5 h⁻¹. -1 The volume hourly space velocity (VHSV) of hydrogen is 90–450 h⁻¹. -1 .

[0024] Furthermore, the cracked gasoline has a distillation range of 50–204°C, a diene value of 5–20 gI2 / 100 g oil, and a bromine value of 10–30 gBr2 / 100 g oil.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] Existing technologies typically use an acidic solution of chloropalladium acid to impregnate a support to prepare palladium-supported hydrocracking catalysts for gasoline cracking. This method involves a relatively high amount of palladium, leading to higher catalyst costs and a larger average palladium particle size. The inventors discovered that reacting chloropalladium acid with ammonia water to generate dichlorotetraamminepalladium, and controlling the pH of the impregnation solution to 9–11, maintains a relatively stable size for the dichlorotetraamminepalladium complex. This complex is then impregnated with a phosphorus-modified alumina-silica support, dried, and calcined to obtain the catalyst of this invention. This method, through the comprehensive coordination of each step, reduces the palladium grain size to 2–3 nm. When applied to the hydrocracking reaction of gasoline cracking, the catalyst of this invention uses a lower palladium content for the same activity, significantly reducing catalyst costs.

[0027] The inventors discovered that using palladium particles with a small and suitable particle size (average particle size of 2-3 nm) loaded on a phosphorus-modified alumina-silica support as a catalyst for the selective hydrogenation of conjugated dienes in cracked gasoline results in excellent diene hydrogenation rates. Compared with existing industrial cracked gasoline hydrogenation catalysts, this invention uses a lower palladium content at the same activity, significantly reducing catalyst costs. Attached Figure Description

[0028] Figure 1 This is a transmission electron microscope (TEM) image of the catalyst obtained in Example 1. Detailed Implementation

[0029] The present invention will be further illustrated below by way of examples, but these examples in no way shall limit the scope of the present invention.

[0030] In this invention, pore size and specific surface area were determined using a Tristar 3000 physical adsorption instrument from Micromeritics. After the sample was pretreated under vacuum at 300°C for 4 hours, it was measured by adsorption with low-temperature nitrogen (77K).

[0031] In this invention, the palladium content in the catalyst is determined by inductively coupled plasma atomic emission spectrometry (ICP). Before the test, 50 mg of sample is completely dissolved in 50 g of hydrofluoric acid solution.

[0032] In this invention, the average particle size of palladium in the catalyst was determined by transmission electron microscopy (TEM) on a Tecnai 20S-TWIN instrument manufactured by FEI Corporation, USA, at an operating voltage of 200 kV. Samples were prepared by dispersion with ethanol prior to the test.

[0033] In this invention, the diene value is determined according to ASTM UOP326-2008, with units of gI² / 100g oil. The diene hydrogenation rate is calculated using the following formula:

[0034]

[0035] Example 1

[0036] (1) Prepare 200g of chloropalladic acid-water solution with a palladium content of 0.05wt%;

[0037] (2) Add ammonia water dropwise to the above solution while stirring. When the pH reaches 10.5, stop adding ammonia water dropwise and continue stirring until the solution changes from flesh-colored to colorless to obtain dichlorotetraamminepalladium impregnation solution.

[0038] (3) Take 50g of alumina-silica support (the silica content in the support is 1.2%, the average pore size of the support is 12nm, and the specific surface area is 130m²). 2 / g), and impregnate an equal volume of 1wt% phosphoric acid solution, then dry at 60℃ for more than 12 hours to obtain a phosphorus-modified carrier;

[0039] (4) Heat the impregnation solution obtained in step (2) to 60°C, then add the phosphorus-modified support obtained in step (3), impregnate at a constant temperature of 60°C for 20 min, and stir slowly while impregnating to make the support uniformly impregnated. Then wash the support with ultrapure water, dry at 110°C for 2 hours, and calcine at 450°C for 4 hours to obtain catalyst D1.

[0040] Figure 1 The image shows a transmission electron microscope (TEM) image of catalyst D1 obtained in Example 1. Statistical analysis of the image shows that the average palladium particle size of this catalyst is 2.6 nm. ICP testing revealed that the palladium content in catalyst D1 is 0.20 wt%. The phosphorus content in the catalyst is 0.59%.

[0041] Catalyst D1 was used in the hydrogenation reaction of cracked gasoline. The cracked gasoline feedstock had a boiling range of 80–140 °C, a diene value of 10–15 g I₂ / 100 g oil, and a bromine value of 15–25 g Br₂ / 100 g oil. The reaction conditions were a reaction temperature of 50 °C, a pressure of 2.5 MPa, and a volume hourly space velocity (VHSV) of 2.5 h⁻¹ for the cracked gasoline. 1 The cycle ratio is 2.0, and the volume hourly space velocity (VHSV) of hydrogen is 100 h⁻¹. 1 The hydrogenation rate of the product diene was 97%.

[0042] Example 2

[0043] (1) Prepare 200g of chloropalladic acid-water solution with a palladium content of 0.04wt%;

[0044] (2) Add ammonia water dropwise to the above solution while stirring. When the pH reaches 10.5, stop adding ammonia water dropwise and continue stirring until the solution changes from flesh-colored to colorless to obtain dichlorotetraamminepalladium impregnation solution.

[0045] (3) Take 50g of alumina-silica support (the silica content in the support is 1.2%, the average pore size of the support is 12nm, and the specific surface area is 130m²). 2 / g), impregnate with 1wt% phosphoric acid in equal volume, and then dry at 60℃ for more than 12 hours to obtain phosphorus-modified support;

[0046] (4) Heat the impregnation solution obtained in step (2) to 60°C, then add the phosphorus-modified support obtained in step (3), impregnate at a constant temperature of 60°C for 20 min, and stir slowly while impregnating to make the support uniformly impregnated. Then wash the support with ultrapure water, dry at 110°C for 2 hours, and calcine at 450°C for 4 hours to obtain catalyst D2.

[0047] The average palladium particle size in catalyst D2 is 2.5 nm, the palladium content is 0.16 wt%, and the phosphorus content in the catalyst is 0.58%.

[0048] Catalyst D2 was used in the hydrogenation reaction of cracked gasoline. The feedstock and conditions were the same as in Example 1, and the hydrogenation rate of the product diene was 92%.

[0049] Example 3

[0050] (1) Prepare 200g of chloropalladic acid-water solution with a palladium content of 0.05wt%;

[0051] (2) Add ammonia water dropwise to the above solution while stirring. When the pH reaches 9.0, stop adding ammonia water and continue stirring until the solution changes from flesh-colored to colorless to obtain dichlorotetraamminepalladium impregnation solution.

[0052] (3) Take 50g of alumina-silica support (the silica content in the support is 1.2%, the average pore size of the support is 12nm, and the specific surface area is 130m²). 2 / g), impregnate with 1wt% phosphoric acid in equal volume, and then dry at 60℃ for more than 12 hours to obtain phosphorus-modified support;

[0053] (4) Heat the impregnation solution obtained in step (2) to 60°C, then add the phosphorus-modified support obtained in step (3), impregnate at a constant temperature of 60°C for 20 min, and stir slowly while impregnating to make the support uniformly impregnated. Then wash the support with ultrapure water, dry at 110°C for 2 hours, and calcine at 450°C for 4 hours to obtain catalyst D3.

[0054] The average palladium particle size in catalyst D3 is 2.8 nm, the palladium content is 0.18 wt%, and the phosphorus content in the catalyst is 0.55%.

[0055] Catalyst D3 was used in the hydrogenation reaction of cracked gasoline. The feedstock and conditions were the same as in Example 1, and the hydrogenation rate of the product diene was 93%.

[0056] Example 4

[0057] (1) Prepare 200g of chloropalladic acid-water solution with a palladium content of 0.05wt%;

[0058] (2) Add ammonia water dropwise to the above solution while stirring. When the pH reaches 10.5, stop adding ammonia water dropwise and continue stirring until the solution changes from flesh-colored to colorless to obtain the impregnation solution.

[0059] (3) Take 50g of alumina-silica support (the silica content in the support is 1.2%, the average pore size of the support is 12nm, and the specific surface area is 130m²). 2 / g), impregnate with 0.5wt% phosphoric acid in equal volume, and then dry at 60℃ for more than 12 hours to obtain phosphorus-modified support;

[0060] (4) Heat the impregnation solution obtained in (2) to 60°C, then add the phosphorus-modified support obtained in step (3), impregnate at a constant temperature of 60°C for 20 min, and stir slowly while impregnating to make the support uniformly impregnated. Then wash the support with ultrapure water, dry at 110°C for 2 hours, and calcine at 450°C for 4 hours to obtain catalyst D4.

[0061] The average palladium particle size in catalyst D4 is 2.9 nm, the palladium content is 0.20 wt%, and the phosphorus content in the catalyst is 0.28%.

[0062] Catalyst D4 was used in the hydrogenation reaction of cracked gasoline. The feedstock and conditions were the same as in Example 1, and the hydrogenation rate of the product diene was 94%.

[0063] Example 5

[0064] (1) Prepare 200g of chloropalladic acid-water solution with a palladium content of 0.05wt%;

[0065] (2) Add ammonia water dropwise to the above solution while stirring. When the pH reaches 10.5, stop adding ammonia water dropwise and continue stirring until the solution changes from flesh-colored to colorless to obtain dichlorotetraamminepalladium impregnation solution.

[0066] (3) Take 50g of alumina-silica support (the silica content in the support is 8%, the average pore size of the support is 13nm, and the specific surface area is 135m²). 2 The same volume of phosphoric acid (1 wt%) was impregnated with 1 wt% phosphoric acid, and then dried at 60°C for more than 12 hours to obtain the phosphorus-modified carrier.

[0067] (4) Heat the impregnation solution obtained in step (2) to 60°C, then add the phosphorus-modified support obtained in step (3), impregnate at a constant temperature of 60°C for 20 minutes, and stir slowly while impregnating to make the support uniformly impregnated. Then wash the support with ultrapure water, dry at 110°C for 2 hours, and calcine at 450°C for 4 hours to obtain catalyst D5.

[0068] The average palladium particle size in catalyst D5 is 2.8 nm, the palladium content is 0.19 wt%, and the phosphorus content in the catalyst is 0.57%.

[0069] Catalyst D5 was used in the hydrogenation reaction of cracked gasoline, with the same feedstock and conditions as in Example 1, and the hydrogenation rate of the product diene was 95%.

[0070] Example 6

[0071] (1) Prepare 200g of chloropalladic acid-water solution with a palladium content of 0.05wt%;

[0072] (2) Add ammonia water dropwise to the above solution while stirring. When the pH reaches 10.5, stop adding ammonia water dropwise and continue stirring until the solution changes from flesh-colored to colorless to obtain dichlorotetraamminepalladium impregnation solution.

[0073] (3) Take 50g of alumina-silica support (the silica content in the support is 12.5%, the average pore size of the support is 15nm, and the specific surface area is 95m²). 2 / g), and impregnate an equal volume of 1wt% phosphoric acid solution, then dry at 60℃ for more than 12 hours to obtain a phosphorus-modified carrier;

[0074] (4) Heat the impregnation solution obtained in step (2) to 60°C, then add the phosphorus-modified support obtained in step (3), impregnate at a constant temperature of 60°C for 20 min, and stir slowly while impregnating to make the support uniformly impregnated. Then wash the support with ultrapure water, dry at 110°C for 2 hours, and calcine at 450°C for 4 hours to obtain catalyst D6.

[0075] The average palladium particle size in catalyst D6 is 2.6 nm, the palladium content is 0.18 wt%, and the phosphorus content in the catalyst is 0.48%.

[0076] This catalyst was used in the hydrogenation reaction of cracked gasoline. The cracked gasoline feedstock had a distillation range of 80-140℃, a diene value of 10-15 g I2 / 100 g oil, and a bromine value of 15-25 g Br2 / 100 g oil. The reaction conditions were a reaction temperature of 50℃, a pressure of 2.5 MPa, and a volume hourly space velocity (VHSV) of 2.5 h⁻¹ for the cracked gasoline. -1 The cycle ratio is 2.0, and the volume hourly space velocity of hydrogen is 100 h⁻¹. -1 The hydrogenation rate of the product diene was 87%.

[0077] Example 7

[0078] (1) Prepare 200g of chloropalladic acid-water solution with a palladium content of 0.05wt%;

[0079] (2) Add ammonia water dropwise to the above solution while stirring. When the pH reaches 10.5, stop adding ammonia water dropwise and continue stirring until the solution changes from flesh-colored to colorless to obtain dichlorotetraamminepalladium impregnation solution.

[0080] (3) Take 50g of alumina-silica support (the silica content in the support is 1.2%, the average pore size of the support is 12nm, and the specific surface area is 130m²). 2 / g), and impregnate an equal volume of 4wt% phosphoric acid solution, then dry at 60℃ for more than 12 hours to obtain a phosphorus-modified carrier;

[0081] (4) Heat the impregnation solution obtained in step (2) to 60°C, then add the phosphorus-modified support obtained in step (3), impregnate at a constant temperature of 60°C for 20 min, and stir slowly while impregnating to make the support uniformly impregnated. Then wash the support with ultrapure water, dry at 110°C for 2 hours, and calcine at 450°C for 4 hours to obtain catalyst D7.

[0082] The average palladium particle size in catalyst D7 is 2.6 nm, the palladium content is 0.17 wt%, and the phosphorus content in the catalyst is 2.20%.

[0083] Catalyst D7 was used in the hydrogenation reaction of cracked gasoline. The feedstock and conditions were the same as in Example 1, and the hydrogenation rate of the product diene was 89%.

[0084] Comparative Example 1

[0085] (1) Prepare 200g of chloropalladic acid-water solution with a palladium content of 0.05wt%;

[0086] (2) Add nitric acid dropwise to the above solution while stirring. When the pH reaches 1.5, stop adding nitric acid and continue stirring for 5 minutes to obtain the impregnation solution.

[0087] (3) Take 50g of alumina-silica support (the silica content in the support is 1.2%, the average pore size of the support is 12nm, and the specific surface area is 130m²). 2 / g), impregnate with 1wt% phosphoric acid in equal volume, and then dry at 60℃ for more than 12 hours to obtain phosphorus-modified support;

[0088] (4) Heat the impregnation solution obtained in (2) to 60°C, then add the modified support obtained in step (3), impregnate at a constant temperature of 60°C for 20 min, stir slowly while impregnating to make the support uniformly impregnated, then wash the support with ultrapure water, dry at 110°C for 2 hours, and calcine at 450°C for 4 hours to obtain catalyst E1.

[0089] The average palladium particle size in catalyst E1 is 3.9 nm, the palladium content is 0.20 wt%, and the phosphorus content in the catalyst is 0.55%.

[0090] The catalyst was used in the hydrogenation reaction of cracked gasoline, with the same feedstock and conditions as in Example 1, and the hydrogenation rate of the product diene was 79%.

[0091] Comparative Example 2

[0092] Compared to Example 1, the difference lies in controlling the pH of the impregnation solution to 8.0, resulting in catalyst E2. This catalyst was used in the hydrocracking of gasoline, with the same feedstock and conditions as in Example 1, and the product diene hydrogenation rate was 81%.

[0093] Comparative Example 3

[0094] (1) Prepare 200g of chloropalladium acid-water solution with a palladium content of 0.05wt%.

[0095] (2) Add ammonia water dropwise to the above solution while stirring. When the pH reaches 10.5, stop adding ammonia water dropwise and continue stirring until the solution changes from flesh-colored to colorless to obtain dichlorotetraamminepalladium impregnation solution.

[0096] (3) Take 50g of alumina-silica support (the silica content in the support is 1.2%, the average pore size of the support is 12nm, and the specific surface area is 130m²). 2 / g), dry at 60℃ for more than 12 hours;

[0097] (4) Heat the impregnation solution obtained in (2) to 60°C, then add the support obtained in step (3), and impregnate at a constant temperature of 60°C for 20 minutes. Stir slowly while impregnating to make the support uniformly impregnated. Then wash the support with ultrapure water, dry at 110°C for 2 hours, and calcine at 450°C for 4 hours to obtain catalyst E3.

[0098] The catalyst E3 palladium has an average particle size of 3.4 nm and a palladium content of 0.20 wt%.

[0099] The catalyst was used in the hydrogenation reaction of cracked gasoline, with the same feedstock and conditions as in Example 1, and the hydrogenation rate of the product diene was 82%.

Claims

1. Use of a pyrolysis gasoline selective hydrogenation catalyst in a pyrolysis gasoline hydrogenation reaction for the removal of conjugated dienes, characterized in that, The cracking gasoline selective hydrogenation catalyst comprises active component palladium and phosphorus modified alumina-silica carrier, the content of the active component palladium is 0.10%-0.25% based on the weight of the catalyst, the average particle size of palladium is 2-3 nm, the content of silica is 0.05%-9.00% based on the weight of the phosphorus modified alumina-silica carrier, and the content of phosphorus element is 0.2%-1.0%.

2. Use according to claim 1, characterized in that, The content of the active component palladium is 0.15%-0.20% based on the weight of the catalyst.

3. Use according to claim 1, characterized in that, The phosphorus-modified alumina-silica support has an average pore diameter of 5 to 20 nm, a specific surface area of 50 to 200 m2 / g. 2 / g.

4. Use according to claim 3, characterized in that, The phosphorus-modified alumina-silica support has an average pore diameter of 7 to 15 nm, a specific surface area of 80 to 180 m2 / g. 2 / g.

5. Use according to any one of claims 1 to 4, characterized in that, The preparation method of the cracking gasoline selective hydrogenation catalyst comprises the following steps: (1) adding ammonia water into an aqueous solution of chloropalladic acid to prepare a dichlorotetraammine palladium impregnation solution; (2) impregnating an alumina-silica carrier with a phosphoric acid solution, drying to obtain a phosphorus modified alumina-silica carrier; (3) impregnating the phosphorus modified alumina-silica carrier obtained in step (2) with the dichlorotetraammine palladium impregnation solution obtained in step (1), drying, and calcining to obtain the catalyst.

6. Use according to claim 5, characterized in that, The content of palladium in the aqueous solution of chloropalladic acid in step (1) is 0.02wt%-0.05wt%.

7. Use according to claim 5, characterized in that, The pH of the dichlorotetraammine palladium impregnation solution in step (1) is controlled to be 9-11.

8. Use according to claim 5, characterized in that, In step (2), the impregnation mode is equal-volume impregnation, and the concentration of the phosphoric acid solution is 0.2wt%-5.0wt%.

9. Use according to claim 8, characterized in that, In step (2), the impregnation mode is equal-volume impregnation, and the concentration of the phosphoric acid solution is 0.3wt%-3.0wt%.

10. Use according to claim 5, characterized in that, In step (3), the impregnation mode is excess impregnation, and the impregnation process is carried out at a temperature of 50-99 ℃ for 10-40 min.

11. Use according to claim 5, characterized in that, In step (3), the drying conditions are as follows: the drying temperature is 100-120 ℃, and the drying time is 60-120 min.

12. The use according to claim 5, characterized in that, In step (3), the calcining conditions are as follows: the calcining temperature is 350-650 ℃, the calcining time is 2-6 hours, and the calcining atmosphere is an oxygen-containing gas.

13. The use according to claim 1, characterized in that, The pyrolysis gasoline is reacted with the hydrogenation catalyst under a hydrogen atmosphere, and the reaction conditions are as follows: the reaction temperature is 35-100℃, the reaction pressure is 2.0-4.0 MPa, the circulation ratio is 1.0-5.0, the volume space velocity of the pyrolysis gasoline is 3-5h -1 , and the volume space velocity of hydrogen is 90-450h -1 .

14. The use according to claim 1, characterized in that, The reaction temperature is 40-80 ℃, and the reaction pressure is 2.5-3.5 MPa.

15. The use according to claim 1, characterized in that, The cracking gasoline has a distillation range of 50-204 ℃, a diene value of 5-20 gI2 / 100g oil, and a bromine value of 10-30 gBr2 / 100g oil.

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