Preparation method of oil slurry selective hydrogenation catalyst

Abstract

The application discloses a preparation method of an oil slurry selective hydrogenation catalyst, and comprises the following steps: (1) preparing a molybdenum-cobalt impregnation solution with a volume greater than the pore volume of a catalyst carrier; (2) adding the catalyst carrier into a rotary vacuum impregnation dryer, spraying the molybdenum-cobalt impregnation solution onto the catalyst carrier under the conditions of rotation and vacuum, and then performing vacuumizing, rotary drying, and calcination to obtain the oil slurry selective hydrogenation catalyst. The oil slurry selective hydrogenation catalyst prepared by the method has both desulfurization activity and low three-ring and four-ring aromatic hydrocarbon saturation performance, and is suitable for a selective hydrogenation desulfurization reaction of catalytic oil slurry.

Description

Technical Field

[0001] This invention relates to an oil slurry hydrogenation catalyst and its preparation method, particularly a method for preparing an oil slurry selective hydrogenation catalyst. Background Technology

[0002] Catalytic oil slurry has a high content of polycyclic aromatic hydrocarbons (PAHs), making it suitable as a feedstock for needle coke production. Needle coke used as a graphite electrode feedstock must have a low sulfur content. Based on the properties and formation mechanism of needle coke, feedstocks with low sulfur content and high tricyclic and tetracyclic aromatic hydrocarbon content should be selected. However, since catalytic oil slurry typically has a high sulfur content, hydrodesulfurization treatment is still required.

[0003] Catalytic slurry oil has a large molecular weight, complex structure, and high aromatic content. Sulfur is mainly distributed in polycyclic aromatic hydrocarbons, gums, and asphaltenes. The presence of these complex compounds easily creates steric hindrance, hindering the adsorption of sulfur atoms by the active sites of the catalyst. The adsorption and deposition of large molecules on the catalyst surface also increases diffusion resistance within the reaction. The feedstock contains a large amount of coking precursors, making the hydrodesulfurization reaction much more difficult than that of distillate oils with relatively smaller molecular weights. Coking on the catalyst surface is also easily formed during the reaction, resulting in a decrease in catalyst activity. Therefore, the production of needle coke feedstock through slurry oil hydrotreating requires achieving high desulfurization activity while simultaneously reducing the hydrosaturation activity of tricyclic and tetracyclic aromatic hydrocarbons, which is difficult to achieve simultaneously. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for preparing a selective hydrogenation catalyst for oil slurry. The selective hydrogenation catalyst prepared by this method simultaneously achieves desulfurization activity and low tricyclic and tetracyclic aromatic hydrocarbon saturation performance, making it suitable for catalyzing selective hydrogenation desulfurization reactions in oil slurry.

[0005] The preparation method of the oil slurry selective hydrogenation catalyst of the present invention includes the following: (1) preparing a molybdenum-cobalt impregnation liquid with a volume greater than the pore capacity of the catalyst support; (2) adding the catalyst support into a rotary vacuum impregnation dryer, spraying the molybdenum-cobalt impregnation liquid onto the catalyst support under rotation and vacuum conditions, then drawing a vacuum again, rotating and drying, and calcining to obtain the oil slurry selective hydrogenation catalyst.

[0006] In the method of the present invention, the volume of the molybdenum-cobalt impregnation solution is 120% to 400% of the pore capacity of the catalyst support, preferably 150% to 200%; the molybdenum-cobalt impregnation solution is generally kept at a temperature of 30 to 40°C.

[0007] In the method of the present invention, the molybdenum-cobalt impregnation solution is prepared by boiling a molybdenum source, a cobalt source, and an inorganic acid at 60-100°C at 120%-400% of the pore capacity of the catalyst support, and then using it after complete dissolution. The molybdenum source is molybdenum trioxide, the cobalt source is basic cobalt carbonate, and the inorganic acid is phosphoric acid.

[0008] In the method of this invention, the viscosity of the molybdenum-cobalt impregnation solution prepared according to 100% of the catalyst support pore capacity is generally 2.4 mm. 2 / s~3.0 mm 2 / s.

[0009] In the method of the present invention, the initial temperature inside the rotary vacuum impregnation dryer is generally not higher than 50°C, preferably 30~40°C, and the vacuum degree (absolute vacuum degree) is not less than 0.04MPa, preferably not less than 0.06MPa.

[0010] In the method of the present invention, the rotation speed is generally 1 to 10 revolutions per minute, preferably 1 to 4 revolutions per minute.

[0011] In the method of the present invention, it is preferable to spray the active metal impregnation solution onto the catalyst support in multiple times, generally 2 to 4 times, wherein the amount of the last spray impregnation is 70% to 90% of the total amount of the active metal impregnation solution.

[0012] In the method of this invention, the vacuum degree (absolute vacuum degree) after the second vacuuming is not less than 0.04 MPa, preferably not less than 0.06 MPa, the drying temperature is 60~95℃, and the catalyst is dried until the dry basis is above 70%. The heating method of the rotary vacuum impregnation dryer is generally an oil bath or steam.

[0013] In the method of this invention, the calcination conditions are: calcination temperature 300~550℃, calcination time 3~8 hours.

[0014] The selective hydrogenation catalyst for oil slurry prepared by the method of the present invention comprises active metals Mo and Co, and a support γ-Al₂O₃; by total weight of the catalyst, Mo, calculated as MoO₃, is 9 wt% to 47 wt%, preferably 24 wt% to 35 wt%, and Co, calculated as CoO, is 2 wt% to 11%, preferably 6 wt% to 9 wt%; the γ-Al₂O₃ has an average pore size of 8.0 to 12.0 nm, preferably 8.5 to 11.5 nm, and a specific surface area of ​​270 to 330 m². 2 ·g -1 Preferred size: 280~320m 2 ·g -1 The pore volume is 0.66~0.99cm. 3 ·g -1 The preferred diameter is 0.68~0.80cm. 3 ·g -1 The total amount of pyridine-infrared acid is 0.4~0.7 mmol·g. -1 The preferred dosage is 0.45~0.65 mmol·g. -1 The amount of Brønsted acid is 0.13~0.20 mmol·g.-1 The preferred dosage is 0.15~0.18 mmol·g. -1 The acid content of L-acid is 0.20~0.57 mmol·g. -1 The preferred dosage is 0.27~0.50 mmol·g. -1 The ratio of Brønsted acid to Lourdesic acid is 0.30 to 1.00, preferably 0.35 to 0.66.

[0015] After sulfidation, the oil slurry selective hydrogenation catalyst of the present invention has an average lamellar length of 7-12 nm, preferably 8-11 nm, in the active phase (taking MoS2 as an example), and an average number of lamellar layers in a single stack layer of 1-5 layers. Based on the total number of stack layers, the proportion of stack layers with 3-5 layers is 40%-90%, preferably 40%-70%.

[0016] The selective hydrogenation catalyst for oil slurry of this invention employs an in-vessel or external sulfidation process for the sulfidation treatment. The amount of sulfiding agent introduced is 90% to 150% of the theoretical sulfur requirement of the catalyst. The sulfidation process uses a programmed temperature rise, maintaining a temperature of 200 to 350°C for 1 to 16 hours. The sulfiding agent is generally one or more of carbon disulfide, dimethyl disulfide, methyl sulfide, and n-butyl sulfide.

[0017] The application of the slurry selective hydrogenation catalyst of the present invention in the slurry selective hydrogenation process generally follows these process conditions: pressure 4.0~6.0 MPa, space velocity 0.5~1.0 h⁻¹. -1 With a temperature of 300~390℃ and a hydrogen-to-oil volume ratio of 100~800, it is particularly suitable for selective hydrogenation processes of oil slurry.

[0018] The selective hydrogenation catalyst for oil slurry of this invention utilizes γ-Al₂O₃ with suitable pore size, specific surface area, pore volume, and acidity. By preparing an active metal impregnation solution larger than the pore volume of the support, and combining this with appropriate vacuum operation steps, a quantitative amount of active metal in the impregnation solution is accurately loaded onto the catalyst support, achieving effective metal loading while simultaneously completing the catalyst drying process. Through the synergistic effect of the γ-Al₂O₃ and the impregnation and drying methods of this invention, the prepared Mo-Co type catalyst, after sulfidation, exhibits an average lamellar length of 7-12 nm in the active phase (taking MoS₂ as an example), with an average of 1-5 lamellar layers in a single stack. Based on the total number of stacks, the proportion of stacks with 3-5 layers is 40%-90%. The increased average lamellar length of the active phase (MoS₂ as an example) enhances the direct desulfurization (DDS) reaction of sulfides. Maintaining a stack ratio of 3-5 layers ensures that the catalyst still possesses relatively high hydrogenation desulfurization performance while achieving the purpose of selective hydrogenation of oil slurry.

[0019] The molecular diameters of 4,6-dimethyldibenzothiophene and 2,4,8-trimethyldibenzothiophene, which are difficult-to-remove sulfur-containing compounds, are 0.88 nm and 0.98 nm, respectively, while the macromolecular diameters of tricyclic and tetracyclic aromatic hydrocarbons are around 1.15 nm. The average pore size of γ-Al₂O₃ in this invention is approximately 10 times the diameter of macromolecular sulfur-containing compounds and tricyclic and tetracyclic aromatic hydrocarbons, allowing the macromolecules to diffuse within the Knudsen diffusion. The average pore size of γ-Al₂O₃ is also greater than 10 times the diameter of macromolecular sulfur-containing compounds, resulting in more frequent collisions between macromolecular sulfur-containing compounds and the catalyst pore walls compared to intermolecular collisions. This increases the contact frequency between reactant molecules and active sites, which is beneficial for the desulfurization reaction. Conversely, the average pore size of γ-Al₂O₃ is less than 10 times the diameter of tricyclic and tetracyclic aromatic hydrocarbons, and the confinement effect of the pores causes more frequent intermolecular collisions than molecular collisions with the catalyst pore walls, hindering contact with active sites and reducing the saturation of tricyclic and tetracyclic aromatic hydrocarbons. In the art, impregnation solutions are generally prepared according to 100% of the carrier pore capacity and using a constant-volume saturated impregnation method under normal pressure. However, the increased active metal content increases the viscosity of the active metal impregnation solution, preventing the solution from effectively entering the carrier pores, affecting the effective migration and dispersion of the metal, resulting in poor metal dispersion. The high viscosity of the impregnation solution severely affected the implementation of the impregnation process. By preparing an active metal impregnation solution with a volume greater than that of the support pores and combining it with reasonable vacuum operation steps, the quantitative amount of active metal in the impregnation solution was accurately loaded onto the catalyst support, overcoming the impregnation problem caused by the high viscosity of the impregnation solution. The large specific surface area and pore volume of γ-Al2O3 facilitated the dispersion of the active metal, and the average number of lamellar layers in a single stack of active phase crystals was 1 to 5. The above process not only completed the effective loading of metal, but also simultaneously completed the catalyst drying process, eliminating the traditional high-temperature drying process, shortening the catalyst preparation process, improving production efficiency, and saving energy. This loading and drying method also made the dispersion of active metal on the support a gentle dispersion process, which could increase the length of the active phase crystals after sulfidation, which was beneficial to improving the selectivity of oil slurry hydrogenation. A higher Brønsted acid / Low acid ratio meant a reduction in L acid in the support, which was beneficial to improving the catalyst's resistance to coking, while an increase in Brønsted acid was beneficial to improving the catalyst's hydrodesulfurization activity. Attached Figure Description

[0020] Figure 1 Transmission electron microscopy image of the catalyst in Example 1 of this invention.

[0021] Figure 2 Transmission electron microscopy image of catalyst in Comparative Example 1. Detailed Implementation

[0022] In this invention, the specific surface area and pore volume were determined using a low-temperature liquid nitrogen adsorption method. The lamellar length and stack-layer ratio were determined using field emission transmission electron microscopy. Specifically, more than 350 MoS2 lamellars were selected, and the average number of layers, average length, and the proportion of 3-5 layer wafers were statistically analyzed. The statistical formula is as follows:

[0023]

[0024] Among them l i N represents the chip length. i Represents the number of layers i, a i Representative chip l i The number, b i Represents the number of layers N i The number. In this invention, wt% represents the mass percentage.

[0025] Example 1

[0026] Add 39.5g of molybdenum trioxide, 21.7g of basic cobalt carbonate, and 8.6g of phosphoric acid to 90mL of water, boil at 70℃ for 60 minutes, and then dilute with water to 180mL to obtain impregnation solution A. The viscosity of the impregnation solution is 2.11mm. 2 / s; 100g of alumina support A is added to a rotary vacuum impregnation dryer and heated to about 35℃. The vacuum is then drawn to 0.08MPa. Under vacuum and rotation conditions, 20mL of impregnation solution A is sprayed onto the alumina support in the rotary vacuum impregnation dryer via atomization at a speed of 2 rpm. After rotating for 30 minutes, the remaining 160mL of impregnation solution is impregnated. The vacuum is then drawn again to 0.09MPa in the rotary vacuum impregnation dryer, and the temperature is raised to 80~90℃ for rotary drying until the dry basis is 71%. The dried catalyst is then calcined at 400℃ for 6 hours to obtain the finished catalyst A. The finished catalyst A is then subjected to in-vessel sulfidation treatment, with the amount of dimethyl disulfide introduced being 120% of the theoretical sulfur requirement of the catalyst. The sulfidation process uses programmed temperature rise, with the temperature raised to 320℃ and held at that temperature for 10 hours.

[0027] Example 2

[0028] 42.1g of molybdenum trioxide, 23.8g of basic cobalt carbonate, and 9.1g of phosphoric acid were added to 90mL of water and boiled at 75℃ for 50 minutes. After dissolution, the solution was diluted with water to 160mL to obtain impregnation solution B, which had a viscosity of 2.16mm. 2 / s; 100g of alumina support B is added to a rotary vacuum impregnation dryer and heated to about 40℃. The vacuum is then evacuated to 0.07MPa. Under vacuum and rotation conditions, 25mL of impregnation solution B is sprayed onto the alumina support in the rotary vacuum impregnation dryer using an atomized method at a speed of 2 rpm. After rotating for 30 minutes, the remaining 135mL of impregnation solution is impregnated. The vacuum is then evacuated again to 0.09MPa in the rotary vacuum impregnation dryer, and the temperature is raised to 80~90℃ for rotary drying until the dry basis is 72%. The dried catalyst is then calcined at 450℃ for 6 hours to obtain the finished catalyst B. The finished catalyst B is then subjected to an in-vessel sulfidation process, introducing dimethyl disulfide at 120% of the theoretical sulfur requirement of the catalyst. The sulfidation process uses a programmed temperature rise, reaching 320℃ and holding at that temperature for 10 hours.

[0029] Example 3

[0030] 36.7 g of molybdenum trioxide, 18.0 g of basic cobalt carbonate, and 3.3 g of phosphoric acid were added to 90 mL of water and boiled at 70 °C for 70 minutes. After dissolution, the solution was diluted with water to 160 mL to obtain impregnation solution C, which had a viscosity of 2.12 mm. 2 / s; 100g of alumina support C is added to a rotary vacuum impregnation dryer and heated to about 40℃. The vacuum is then evacuated to 0.09MPa. Under vacuum and rotation conditions, 30mL of impregnation solution C is sprayed onto the alumina support in the rotary vacuum impregnation dryer via atomization at a speed of 2 rpm. After rotating for 30 minutes, the remaining 130mL of impregnation solution is impregnated. The vacuum is then evacuated again to 0.08MPa in the rotary vacuum impregnation dryer, and the temperature is raised to 80~90℃ for rotary drying until the dry basis is 73%. The dried catalyst is then calcined at 550℃ for 6 hours to obtain the finished catalyst C. The finished catalyst C is then subjected to in-vessel sulfidation, with the amount of dimethyl disulfide introduced being 120% of the theoretical sulfur requirement for the catalyst. The sulfidation process uses a programmed temperature rise, with the temperature raised to 320℃ and held at that temperature for 10 hours.

[0031] Example 4

[0032] 44.9 g of molybdenum trioxide, 26.1 g of basic cobalt carbonate, and 9.8 g of phosphoric acid were added to 90 mL of water and boiled at 75 °C for 60 minutes. After dissolution, the solution was diluted with water to 180 mL to obtain impregnation solution D, which had a viscosity of 2.16 mm. 2 / s; 100g of alumina support D is added to a rotary vacuum impregnation dryer and heated to about 35℃. The vacuum is then evacuated to 0.08MPa. Under vacuum and rotation conditions, 30mL of impregnation liquid D is sprayed onto the alumina support in the rotary vacuum impregnation dryer via atomization at a speed of 2 rpm. After rotating for 30 minutes, the remaining 150mL of solution is impregnated. The vacuum is then evacuated again to 0.08MPa in the rotary vacuum impregnation dryer, and the temperature is raised to 80~90℃ for rotary drying until the dry basis is 75%. The dried catalyst is then calcined at 480℃ for 6 hours to obtain the finished catalyst D. The finished catalyst D is then subjected to in-vessel sulfidation treatment, with the amount of dimethyl disulfide introduced being 120% of the theoretical sulfur requirement of the catalyst. The sulfidation process uses programmed temperature rise, with the temperature raised to 320℃ and held at that temperature for 10 hours.

[0033] Example 5

[0034] In a 200 mL fixed-bed small-scale hydrogenation unit, catalysts A, B, C, and D were used respectively, at a hydrogen partial pressure of 5.0 MPa and a liquid hourly space velocity of 0.7 h⁻¹. -1 The hydrogen-to-oil volume ratio is 500 Nm. 3 / m 3 The raw materials in Table 2 were hydrogenated under an average reaction temperature of 340℃.

[0035] Comparative Example 1

[0036] 100g of alumina carrier E (water absorption rate 75mL / 100g) was placed in a boiling pot. Under rotating conditions, 75mL of an impregnation solution containing 39.5g of molybdenum trioxide, 21.7g of basic cobalt carbonate, and 8.6g of phosphoric acid was sprayed into the alumina carrier in the boiling pot via atomization. The viscosity of the impregnation solution was 2.87mm. 2 / s; After the solution is sprayed, it continues to rotate in the boiling pot for 30 minutes, and after static curing at an ambient temperature of 26℃ for 10 hours, it is dried at 120℃ for 6 hours and calcined at 500℃ for 4 hours to obtain the finished catalyst E. The finished catalyst E is sulfided using an in-plant sulfidation process, with the amount of dimethyl disulfide introduced being 120% of the theoretical sulfur requirement of the catalyst. The sulfidation process uses a programmed temperature rise, and the temperature is held at 320℃ for 10 hours.

[0037] Comparative Example 2

[0038] 39.5g of molybdenum trioxide, 21.7g of basic cobalt carbonate, and 8.6g of phosphoric acid were added to 75mL of water and boiled at 70℃ for 60 minutes. After dissolution, the solution was diluted with water to 180mL to obtain impregnation solution F, which had a viscosity of 2.11mm. 2 / s; 100g of alumina support E is added to a rotary vacuum impregnation dryer and heated to about 35℃. The vacuum is then evacuated to 0.08MPa. Under vacuum and rotation conditions, 20mL of impregnation solution F is sprayed onto the alumina support in the rotary vacuum impregnation dryer using an atomized method at a speed of 2 rpm. After rotating for 30 minutes, the remaining 160mL of impregnation solution is impregnated. The vacuum is then evacuated again to 0.09MPa in the rotary vacuum impregnation dryer, and the temperature is raised to 80~90℃ for rotary drying until the dry basis is 71%. The dried catalyst is then calcined at 400℃ for 6 hours to obtain the finished catalyst F. The finished catalyst F is then subjected to in-vessel sulfidation, with the amount of dimethyl disulfide introduced being 120% of the theoretical sulfur requirement of the catalyst. The sulfidation process uses a programmed temperature rise, with the temperature raised to 320℃ and held at that temperature for 10 hours.

[0039] Comparative Example 3

[0040] 100g of alumina carrier B (water absorption rate 90mL / 100g) was placed in a boiling pot. Under rotating conditions, 90mL of an impregnation solution containing 42.1g of molybdenum trioxide, 23.8g of basic cobalt carbonate, and 9.1g of phosphoric acid was sprayed into the alumina carrier in the boiling pot via atomization. The viscosity of the impregnation solution was 2.77mm. 2 / s; After the solution is sprayed, it continues to rotate in the boiling pot for 30 minutes, and after static curing at an ambient temperature of 26℃ for 10 hours, it is dried at 120℃ for 6 hours and calcined at 500℃ for 4 hours to obtain the finished catalyst G. The finished catalyst G is sulfided using an in-plant sulfidation process, with the amount of dimethyl disulfide introduced being 120% of the theoretical sulfur requirement of the catalyst. The sulfidation process uses a programmed temperature rise, and the temperature is held at 320℃ for 10 hours.

[0041] Comparative Example 4

[0042] 44.9 g of molybdenum trioxide, 26.1 g of basic cobalt carbonate, and 9.8 g of phosphoric acid were added to 70 mL of water and boiled at 70 °C for 60 minutes. After dissolution, the solution was diluted with water to 180 mL to obtain impregnation solution F, which had a viscosity of 2.23 mm. 2 / s; 100g of alumina support H is added to a rotary vacuum impregnation dryer and heated to about 35℃. The vacuum is then drawn to 0.08MPa. Under vacuum and rotation conditions, 20mL of impregnation solution H is sprayed onto the alumina support in the rotary vacuum impregnation dryer via atomization at a speed of 2 rpm. After rotating for 30 minutes, the remaining 160mL of impregnation solution is impregnated. The vacuum is then drawn again to 0.09MPa in the rotary vacuum impregnation dryer, and the temperature is raised to 80~90℃ for rotary drying until the dry basis is 72%. The dried catalyst is then calcined at 400℃ for 6 hours to obtain the finished catalyst H. The finished catalyst H is then subjected to in-vessel sulfidation, with the amount of dimethyl disulfide introduced being 120% of the theoretical sulfur requirement of the catalyst. The sulfidation process uses programmed temperature rise, reaching 320℃ and holding at that temperature for 10 hours.

[0043] Comparative Example 5

[0044] Catalysts E, F, G, and H were evaluated separately, using the same evaluation method as in Example 5.

[0045] Example 6

[0046] This example compares the physicochemical properties of the catalysts prepared in the above examples with the results of operating the above examples on a small-scale hydrogenation unit for 600 hours, as shown in Tables 1 and 2.

[0047] Table 1. Main properties of the catalyst

[0048]

[0049] Table 2. Test results of the catalyst

[0050]

[0051] The results in Table 2 show that the sulfur content in the slurry after hydrorefining of the catalyst of the present invention is <0.4%, and the loss rate of (tricyclic + tetracyclic) aromatics is 2 percentage points, which meets the feed requirements of high-end graphite units.

Claims

1. A method for preparing an oil slurry selective hydrogenation catalyst, characterized in that... The process includes the following steps: (1) preparing a molybdenum-cobalt impregnation solution with a volume greater than the pore capacity of the catalyst support γ-Al2O3; (2) adding the catalyst support γ-Al2O3 into a rotary vacuum impregnation dryer, spraying the molybdenum-cobalt impregnation solution onto the catalyst support under rotation and vacuum conditions, then evacuating again, rotating and drying, and calcining to obtain an oil slurry selective hydrogenation catalyst; the γ-Al2O3 has an average pore size of 8.0~12.0 nm and a specific surface area of ​​270~330 m². 2 ·g -1 The pore volume is 0.66~0.99cm. 3 ·g -1 The total amount of pyridine-infrared acid is 0.4~0.7 mmol·g. -1 The amount of Brønsted acid is 0.13~0.20 mmol·g. -1 The acid content of L-acid is 0.20~0.57 mmol·g. -1 The Brønsted acid / Lylene acid ratio is 0.30~1.00; The initial temperature inside the rotary vacuum impregnation dryer is not higher than 50°C, and the absolute vacuum degree is not less than 0.04 MPa; The absolute vacuum degree after the second vacuuming is not less than 0.04 MPa, and the drying temperature is 60~95℃; The molybdenum-cobalt impregnation solution is prepared by boiling a molybdenum source, a cobalt source, and an inorganic acid at 60-100°C at 120%-400% of the pore capacity of the catalyst support, and then using it after complete dissolution. The molybdenum source is molybdenum trioxide, the cobalt source is basic cobalt carbonate, and the inorganic acid is phosphoric acid. After sulfidation treatment, the average lamellar length of the active phase MoS2 in the selective hydrogenation catalyst is 7~12nm, and the average number of lamellar layers in a single stack is 1~5. Based on the total number of stacks, the proportion of stacks with 3~5 layers is 40%~90%.

2. The method according to claim 1, characterized in that: The viscosity of the molybdenum-cobalt impregnation solution, prepared to 100% of the catalyst carrier pore capacity, is 2.4 mm. 2 / s~3.0 mm 2 / s.

3. The method according to claim 1, characterized in that: The initial temperature inside the rotary vacuum impregnation dryer is 30~40℃.

4. The method according to claim 1, characterized in that: The rotational speed is 1~10 revolutions / min.

5. The method according to claim 1, characterized in that: The active metal impregnation solution is sprayed onto the catalyst support in multiple stages, with the final spray impregnation amount being 70% to 90% of the total active metal impregnation solution.

6. The method according to claim 5, characterized in that: The active metal impregnation solution is sprayed onto the catalyst support in 2 to 4 stages.

7. The method according to claim 1, characterized in that: Dry the catalyst until the dry basis content is above 70%.

8. The method according to claim 1, characterized in that: The roasting conditions are: roasting temperature 300~550℃, roasting time 3~8 hours.

9. The method according to claim 1, characterized in that: After sulfidation treatment, the average lamellar length of the active phase MoS2 in the selective hydrogenation catalyst is 8-11 nm; based on the total number of stack layers, the proportion of stack layers with 3-5 layers is 40%-70%.

10. The method according to claim 1, characterized in that: The vulcanization treatment is carried out in-vessel or external vulcanization process. The amount of vulcanizing agent introduced is 90% to 150% of the theoretical sulfur required by the catalyst. The vulcanization process adopts programmed temperature rise, and the temperature is kept constant at 200 to 350°C for 1 to 16 hours. The vulcanizing agent is one or more of carbon disulfide, dimethyl disulfide, methyl sulfide and n-butyl sulfide.

11. The oil slurry selective hydrogenation catalyst prepared according to any one of claims 1 to 8, characterized in that: The oil slurry selective hydrogenation catalyst includes active metals Mo and Co, as well as the support γ-Al2O3; by total catalyst weight, Mo is 9wt%~47wt% as MoO3, and Co is 2%~11% as CoO.

12. The selective hydrogenation catalyst for oil slurry according to claim 11, characterized in that: Based on the total weight of the catalyst, Mo, calculated as MoO3, is 24wt%~35wt%, and Co, calculated as CoO, is 6wt%~9wt%.

13. The application of the slurry selective hydrogenation catalyst prepared according to any one of claims 1 to 8 in the process of selective hydrogenation of slurry oil to prepare needle coke feedstock, wherein the process conditions are: pressure 4.0~6.0 MPa, space velocity 0.5~1.0 h⁻¹. -1 Temperature 300~390℃, hydrogen-to-oil volume ratio 100~800.

Images