A process for the preparation of a catalyst having hydrodesulfurization, denitrification and aromatic saturation properties

Abstract

The application discloses a preparation method of a catalyst with hydrogen desulfurization, denitrification and aromatic hydrocarbon saturation performance, and comprises the following steps: taking gamma-Al2O3 or gamma-Al2O3 modified by an additive as a carrier, impregnating a first-stage impregnation solution containing a heteropolyacid salt, drying to obtain a first-stage catalyst semi-product, impregnating a second-stage impregnation solution containing an active metal, and drying and calcining to obtain a catalyst product, wherein the heteropolyacid salt is Ni6[WM3(H2O)2(MW9O 36 )2], and M is one or more of Fe, Zn, Cu and Co. The catalyst prepared by the method is beneficial to improving adsorption and reaction of non-hydrocarbon compounds and improving desulfurization, denitrification and aromatic hydrocarbon saturation activity of the catalyst.

Description

Technical Field

[0001] This invention belongs to the field of hydrorefining catalyst technology, and relates to a method for preparing a catalyst with hydrodesulfurization, denitrogenation and aromatic saturation properties. Background Technology

[0002] With the accelerating trend of crude oil becoming increasingly degraded and heavier, the sulfur, nitrogen, and aromatic hydrocarbon content of feedstock oils is continuously increasing during the hydrorefining process of jet fuel and diesel.

[0003] Sulfides are common and relatively abundant non-hydrocarbon compounds in kerosene fractions. Excessive sulfide content negatively impacts the cleanliness of the engine combustion chamber. Thiols are reactive sulfides that are corrosive to aircraft parts and give fuel an unpleasant odor; therefore, the national standard for No. 3 jet fuel imposes limits on both total sulfur and thiol sulfur content. Sulfides in kerosene fractions mainly include thiols, thioethers, disulfides, tetrahydrothiophene, and thiophene. The hydrogenation reactivity of different types of sulfur-containing compounds increases in the following order: thiophene < tetrahydrothiophene ≈ thioethers < disulfides < thiols.

[0004] Kerosene fractions generally have low nitrogen content, and basic nitrogen compounds are the most direct cause of color and stability problems in jet fuels. Trace amounts of basic nitrogen compounds, such as pyridine and quinoline, can synergistically affect color stability with phenols. Generally, a basic nitrogen content of less than 3 μg / g is sufficient to ensure the stability of the fuel's color.

[0005] The aromatic hydrocarbons in petroleum fractions mainly include the following four categories: (1) monocyclic aromatic hydrocarbons, including benzene and alkylbenzenes, benzocycloalkanes, etc.; (2) bicyclic aromatic hydrocarbons, including naphthalene and alkylnaphthalene, biphenyl and naphthocycloalkanes, etc.; (3) tricyclic aromatic hydrocarbons, including anthracene, phenanthrene and fluorene and their alkyl derivatives, etc.; (4) polycyclic aromatic hydrocarbons, such as pyrene, fluoranthene, etc.

[0006] The aromatic nuclei in aromatic hydrocarbons are very stable and difficult to break directly. Large fused-ring and polycyclic aromatic hydrocarbons can only undergo ring-opening and further cracking reactions after the aromatic rings have been hydrogenated to saturation. Studies have shown that the hydrogenation reactions of aromatic hydrocarbons follow these patterns: ① The equilibrium constant of the hydrogenation reaction decreases with increasing reaction temperature; ② In the 600K–700K range, the equilibrium constant lgKp for complete hydrogenation saturation of aromatic hydrocarbons decreases with increasing number of rings in the molecule; ③ In the 600K–700K range, the equilibrium constant for the hydrogenation saturation reaction of the first ring in fused-ring aromatic hydrocarbons is the largest, while the equilibrium constants for the second and third ring saturation reactions decrease sequentially; ④ Above 600K, the equilibrium constants for the hydrogenation saturation reactions of aromatic hydrocarbons are relatively small, therefore higher pressures are necessary to improve the equilibrium conversion rate; ⑤ Hydrogenation saturation of the first aromatic ring in fused-ring aromatic hydrocarbons is relatively easy, with a relative reaction rate constant of 1.38, which is 10 times that of benzene hydrogenation, while hydrogenation saturation of the remaining aromatic ring is more difficult, with a reaction rate close to that of benzene.

[0007] The aromatic hydrocarbon content is directly related to the smoke point of jet fuel. The No. 3 jet fuel specification requires an aromatic hydrocarbon volume content of no more than 20.0% and a smoke point of no less than 25.0 mm. Straight-run kerosene fractions mainly contain monocyclic and bicyclic aromatic hydrocarbons, and essentially no tricyclic or higher aromatic hydrocarbons. Monocyclic aromatic hydrocarbons mainly include alkylbenzenes, indene, tetrahydronaphthalene, and indene derivatives, while bicyclic aromatic hydrocarbons mainly include naphthalene and naphthalene derivatives. Hydrogenation removal of monocyclic and bicyclic aromatic hydrocarbons is more difficult than that of multicyclic aromatic hydrocarbons. Therefore, developing catalysts with higher aromatic hydrocarbon removal activity is of great significance for producing No. 3 jet fuel from low-smoke-point kerosene.

[0008] In industry, aromatic saturated catalysts for distillate oils mainly include two types: supported metal sulfide catalysts and supported noble metal catalysts. When the sulfur and nitrogen content in the feed oil is high, γ-Al₂O₃-supported sulfide NiMo, NiW, and CoMo catalysts are typically used. When the sulfur and nitrogen content in the feed oil is sufficiently low, highly active supported noble metal catalysts are more effective.

[0009] The advantage of supported metal sulfide catalysts is that they are not affected by poisoning in the feedstock; their disadvantage is that they have low hydrogenation activity and the reaction rate is very slow under normal hydrogenation conditions. To achieve a high degree of aromatic removal, harsh reaction conditions (360-425°C) are usually required, while at high temperatures, thermodynamic equilibrium limits the degree of aromatic hydrogenation.

[0010] Supported noble metal catalysts are mainly used in two-stage processes involving desulfurization and aromatic removal. The first stage uses a traditional sulfide catalyst, which reduces the sulfur content through harsh hydrogenation treatment. The second stage uses a noble metal catalyst for aromatic saturation. Its advantages include deep aromatic removal under relatively mild reaction conditions (150–350°C). Its disadvantages include the second-stage catalyst being highly sensitive to sulfides in the feedstock, requiring the sulfur content in the product to be reduced to the ppm level after the first-stage refining process.

[0011] Currently, the most studied aromatic hydrocarbon removal catalysts mainly fall into the following three categories:

[0012] (1) Non-precious metal sulfide catalysts. The advantage of this type of catalyst is that it is not sensitive to the poisoning effect of sulfide species in the raw materials and has strong adaptability. It is also the most widely used in industry at present, but it generally has the problem of low hydrogenation activity.

[0013] (2) Noble metal catalysts: These catalysts have high hydrogenation activity and can achieve deep saturation of aromatics under relatively mild conditions. However, when the feedstock contains high levels of sulfides, the catalyst is easily poisoned and deactivated, and the production cost is high.

[0014] (3) Other types of catalysts, mainly including amorphous alloy catalysts, transition metal carbon or nitride catalysts, etc., but these catalysts have harsh preparation conditions, poor stability, and high production costs, which limit their large-scale application.

[0015] Patent CN101099934A discloses a metal nitride catalyst for the saturated hydrogenation of aromatics. A nickel-molybdenum bimetallic nitride is supported on alumina. After stirring and impregnation at room temperature for 2–4 hours, the catalyst is filtered, thoroughly dried, and then vacuum-dried at 60–100°C for 5–8 hours. The catalyst is then pressed into tablets, sieved, and directly calcined. The process involves raising the temperature from room temperature to 650–680°C at a rate of 10°C / min in an Ar gas stream, maintaining this temperature for 2 hours, with an Ar gas hourly space velocity of 500–1500 h⁻¹. -1 Switch to H2 airflow and maintain for 2 hours, then cool to room temperature in H2 at an H2 space velocity of 500–1500 h⁻¹. -1 Finally, the catalyst is passivated in N2 containing 1% O2 for 4 hours and then used for the saturated hydrogenation of monocyclic and bicyclic aromatic hydrocarbons, exhibiting high catalytic activity. However, the calcination process of the catalyst prepared by this method is cumbersome, resulting in high production costs and making it uneconomical.

[0016] Patent CN105521797B discloses a supported bimetallic catalyst and its preparation method, which includes impregnating a support with a compound containing a first active metal component and a compound containing a second active metal component, reducing and activating the support, and impregnating the reduced and activated product with a solution containing the second active metal component in a reducing or inert atmosphere. The prepared catalyst exhibits significantly higher aromatic saturation activity. However, this method requires the use of precious metals, resulting in high economic costs.

[0017] Patent CN106582707B discloses a supported alloy-type aromatic saturated catalyst and its preparation method, mainly addressing the problem of low hydrogenation saturation of polycyclic aromatic hydrocarbons in existing technologies. By using at least one catalyst selected from alumina, silicon oxide, titanium oxide, or amorphous aluminum silicate as a support, and an alloy formed from noble and non-noble metals as the active component, it exhibits high hydrogenation saturation activity. However, the catalyst prepared by this method requires the use of noble metals, resulting in higher economic costs.

[0018] US Patent 5308814 discloses various support materials for a noble metal dearomatic catalyst composition. The support is prepared using Y and high-temperature resistant inorganic oxides (such as silica, alumina, or silica and alumina), with platinum and palladium loaded on them. The proportion of Y zeolite in the support is 10–90%. This method uses noble metals and molecular sieves, resulting in high production costs.

[0019] Patent CN109794299A discloses a method for preparing a hydrogenation catalyst, using molecular sieves and γ-Al₂O₃ as supports, impregnating a heteropoly acid solution, and loading tungsten and nickel. To improve the hydrogenation activity of the catalyst prepared by this method, molecular sieves need to be introduced during the support preparation process, increasing the catalyst preparation process and cost. Because the hydrogenation active phase constructed by this catalyst is a traditional type II active phase, it does not form a stacked structure with a specific morphology, resulting in less than ideal hydrogenation conversion effects on polar substances such as aromatics. Its hydrogenation activity shows limited improvement compared to current mainstream catalysts on the market, and there is still considerable room for improvement. Summary of the Invention

[0020] The purpose of this invention is to provide a method for preparing a catalyst with hydrodesulfurization, denitrification and aromatic saturation properties. The catalyst prepared by this method is beneficial to improving the adsorption and reaction of non-hydrocarbon compounds and improving the desulfurization, denitrification and aromatic saturation activities of the catalyst.

[0021] To achieve the above objectives, the present invention provides a method for preparing a catalyst with hydrodesulfurization, denitrification, and aromatic saturation properties, comprising: using γ-Al2O3 or γ-Al2O3 modified with an additive as a support, impregnating a first-stage impregnation solution containing a heteropoly acid salt, drying to obtain a first-stage catalyst semi-finished product, then impregnating a second-stage impregnation solution containing an active metal, and obtaining the catalyst finished product after drying and calcination, wherein the heteropoly acid salt is Ni6[WM3(H2O)2(MW9O 36 [2], M is one or more of Fe, Zn, Cu, and Co.

[0022] The preparation method of the catalyst with hydrodesulfurization, denitrification and aromatic saturation properties described in this invention, wherein the second impregnation solution is a stable solution containing two active metals, W and Ni, and the tungsten source can be ammonium metatungstate and the nickel source can be nickel nitrate.

[0023] The preparation method of the catalyst with hydrodesulfurization, denitrification and aromatic saturation properties described in this invention further includes one or more of citric acid, tartaric acid and oxalic acid in the second impregnation solution.

[0024] The method for preparing the catalyst with hydrodesulfurization, denitrogenation and aromatic saturation properties described in this invention further includes one or more C1-C8 alcohols in the first impregnation solution, which reduces the surface tension of the solution and promotes the migration of active metals within the pores of the support.

[0025] The method for preparing the catalyst with hydrodesulfurization, denitrogenation and aromatic saturation properties according to the present invention, wherein the C1-C8 alcohol is methanol, ethanol, ethylene glycol, propanol, glycerol, butanol, butanediol, pentanol, hexanol, octanol and methylcyclohexanol.

[0026] The method for preparing the catalyst with hydrodesulfurization, denitrogenation and aromatic saturation properties according to the present invention, wherein the mass ratio of heteropolyacid salt to C1-C8 alcohol in the first impregnation solution is (78-95):(5-22), preferably (82-93):(7-18).

[0027] The preparation method of the catalyst with hydrodesulfurization, denitrogenation and aromatic saturation properties according to the present invention involves calcination at 300℃~600℃ for 2h~20h, preferably at 380℃~560℃ for 3h~10h.

[0028] The method for preparing the catalyst with hydrodesulfurization, denitrogenation and aromatic saturation properties according to the present invention, wherein the γ-Al2O3 modified by the auxiliary agent is Si or Ti modified γ-Al2O3.

[0029] Currently, commonly used hydrogenation catalysts typically use Al₂O₃ or modified Al₂O₃ as the support material, and the active metal component is usually supported W-Ni, Co-Mo, Mo-Ni, Co-Mo-Ni, W-Mo-Ni, etc. Traditional loading methods uniformly disperse the active metal on the support surface, improving its utilization rate. However, research shows that moderate aggregation of the active metal on the support surface, especially when it forms a stacked structure with a specific morphology, can better eliminate steric hindrance, facilitating the adsorption and reaction of sulfur-containing, nitrogen-containing, and aromatic molecules, thereby improving the catalyst's hydrogenation refining activity.

[0030] The catalyst prepared by the method provided in this invention contains Ni and W as its active metal components. During catalyst preparation, a first-stage catalyst semi-finished product with a specific stacking morphology is formed on a support by first loading an active heteropolyacid salt solution containing C1-C8 alcohols. The active metal loaded in this first-stage catalyst semi-finished product acts as a seed crystal for subsequently loaded active metals, inducing the directional loading of subsequent active metals and resulting in a stacking structure with a specific morphology on the support surface. The prepared catalyst can effectively promote the adsorption and reaction of non-hydrocarbon compounds, thereby significantly improving the catalyst's desulfurization, denitrification, and aromatic saturation activity. Attached Figure Description

[0031] Figure 1 This is a transmission electron microscope (TEM) image of a section of the semi-finished catalyst prepared in Example 1.

[0032] Figure 2 The image shown is a transmission electron microscope (TEM) image of the finished catalyst prepared in Example 1.

[0033] Figure 3 This is a transmission electron microscope (TEM) image of a section of the semi-finished catalyst prepared in Example 2.

[0034] Figure 4 The image shown is a transmission electron microscope (TEM) image of the finished catalyst prepared in Example 2.

[0035] Figure 5 This is a transmission electron microscope (TEM) image of a section of the semi-finished catalyst prepared in Example 3.

[0036] Figure 6 The image shown is a transmission electron microscope (TEM) image of the finished catalyst prepared in Example 3.

[0037] Figure 7 This is a transmission electron microscope (TEM) image of a section of the semi-finished catalyst prepared in Example 4.

[0038] Figure 8 The image shown is a transmission electron microscope (TEM) image of the finished catalyst prepared in Example 4.

[0039] Figure 9 Transmission electron microscopy (TEM) image of the finished catalyst prepared in Comparative Example 1.

[0040] Figure 10 Transmission electron microscopy (TEM) image of the finished catalyst prepared for Comparative Example 2. Detailed Implementation

[0041] The present invention will now be described in detail through embodiments. It should be noted that the following embodiments are only for further illustration of the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above description.

[0042] Example 1:

[0043] 1000g of pseudoboehmite powder, 53g of Tianqing powder, 22g of citric acid, and 650ml of 3-5% dilute nitric acid were weighed and mixed evenly. The mixture was then extruded using an extruder, dried at 110℃ for 10h, and calcined at 560℃ in air to obtain a γ-Al₂O₃ support. 100g of the prepared support was weighed, and then 9.1g and 0.9g of Ni₆[WCo₃(H₂O)₂(CoW₉O)₃) were weighed. 36 [2] and ethylene glycol, with 41g of deionized water added, are mixed to prepare an impregnation solution for equal-volume impregnation, followed by vacuum drying to prepare a first-stage catalyst. An impregnation solution containing active metals W and Ni is prepared with 12g of ammonium metatungstate and 8.6g of nickel nitrate, and the first-stage catalyst semi-finished product is impregnated with an equal volume. After vacuum drying and calcination at 400℃ for 7h, the finished catalyst is obtained.

[0044] Example 2:

[0045] 950g of pseudoboehmite powder, 50g of metatitanic acid, 45g of Tianqing powder, 22g of citric acid, and 660ml of 3-5% dilute nitric acid were weighed and mixed evenly. The mixture was then extruded using an extruder, dried at 120℃ for 10h, and calcined at 540℃ in air to obtain a Ti-containing γ-Al₂O₃ support. 100g of the prepared support was weighed, and then 8.2g and 1.8g of Ni₆[WFe₃(H₂O)₂(FeW₉O)₃) were weighed. 36 [2] and butanediol, with 43g of deionized water, were mixed to prepare an impregnation solution of equal volume for impregnation, followed by vacuum drying to prepare a first-stage catalyst. An impregnation solution containing active metals W and Ni was prepared with 12g of ammonium metatungstate and 8.6g of nickel nitrate, and the first-stage catalyst semi-finished product was impregnated with an equal volume. After vacuum drying and calcination at 450℃ for 8h, the finished catalyst was obtained.

[0046] Example 3:

[0047] 950g of pseudoboehmite powder, 50g of silica sol, 44g of Tianqing powder, 22g of citric acid, and 660ml of 3-5% dilute nitric acid were weighed and mixed evenly. The mixture was then extruded into shape using an extruder, dried at 120℃ for 10h, and calcined at 540℃ in air to obtain a Si-containing γ-Al₂O₃ support. 100g of the prepared support was weighed, and then 9.5g and 0.5g of Ni₆[WZn₃(H₂O)₂(ZnW₉O)₃ were weighed. 36 [2] and ethanol, add 42g of deionized water to prepare an impregnation solution for equal volume impregnation, vacuum drying to prepare a first-stage catalyst. An impregnation solution containing active metals W and Ni was prepared with 12g of ammonium metatungstate and 8.6g of nickel nitrate, and the first-stage catalyst semi-finished product was impregnated with an equal volume. After vacuum drying and calcination at 470℃ for 10h, the catalyst finished product was obtained.

[0048] Example 4:

[0049] 1000g of pseudoboehmite powder, 53g of Tianqing powder, 22g of citric acid, and 650ml of 3-5% dilute nitric acid were weighed and mixed evenly. The mixture was then extruded using an extruder, dried at 110℃ for 10h, and calcined at 560℃ in air to obtain the γ-Al₂O₃ support. 100g of the prepared support was weighed, and then 8.9g and 1.1g of Ni₆[WCu₃(H₂O)₂(CuW₉O)₃ were weighed. 36 [2] and methylcyclohexanol were added to 41g of deionized water to prepare an impregnation solution for equal-volume impregnation. The solution was then vacuum dried to prepare a first-stage catalyst. An impregnation solution containing active metals W and Ni was prepared using 12g of ammonium metatungstate and 8.6g of nickel nitrate. The first-stage catalyst semi-finished product was impregnated with an equal volume, and then vacuum dried and calcined at 550℃ for 2h to obtain the finished catalyst.

[0050] Comparative Example 1:

[0051] 1000g of boehmite powder, 53g of Tianqing powder, 22g of citric acid, and 650ml of 3-5% dilute nitric acid were weighed and mixed evenly. The mixture was then extruded and shaped using an extruder, dried at 110℃ for 10h, and calcined at 560℃ in air to obtain a γ-Al₂O₃ support. 100g of the obtained support was weighed and impregnated with an impregnation solution containing active metals W and Ni, prepared with 12g of ammonium metatungstate and 8.6g of nickel nitrate. The support was then impregnated with an equal volume of solution, and after vacuum drying and calcination at 400℃ for 7h, the catalyst product was obtained.

[0052] Comparative Example 2:

[0053] 950g of boehmite powder, 50g of metatitanic acid, 45g of tianqing powder, 22g of citric acid, and 660ml of 3-5% dilute nitric acid were weighed and mixed evenly. The mixture was then extruded into shape using an extruder, dried at 120℃ for 10h, and calcined at 540℃ in air to obtain a Ti-containing γ-Al₂O₃ support. 100g of the prepared support was weighed and impregnated with an impregnation solution containing active metals W and Ni prepared with 12g of ammonium metatungstate and 8.6g of nickel nitrate. The support was then impregnated with an equal volume of solution, and after vacuum drying and calcination at 450℃ for 8h, the catalyst product was obtained.

[0054] Comparative Example 3

[0055] 950g of pseudoboehmite powder, 50g of silica sol, 44g of Tianqing powder, 22g of citric acid, and 660ml of 3-5% dilute nitric acid were weighed and mixed evenly. The mixture was then extruded using an extruder, dried at 120℃ for 10h, and calcined at 540℃ in air to obtain a Si-containing γ-Al₂O₃ support. 100g of the prepared support was weighed, and then 17.6g and 1.4g of Ni₆[WZn₃(H₂O)₂(ZnW₉O)₃ were weighed. 36 [2] and ethanol, add 55g of deionized water to prepare an impregnation solution of equal volume for impregnation, vacuum dry, and calcine at 470℃ for 10h to obtain the catalyst product.

[0056] Transmission electron microscopy images of the catalysts prepared above are shown below. Figures 1-10 As can be seen from the figure, the catalyst semi-finished product prepared according to the present invention shows a relatively obvious stacking structure, and the surface of the finished catalyst also shows an obvious stacking structure, while the catalyst prepared by conventional methods does not show this structure on its surface.

[0057] Depend on Figures 1 to 8 It can be seen that, compared with the corresponding semi-finished catalyst, the finished catalyst exhibits a clearer and more distinct stacked morphology. This is mainly because the heteropolyacid salt structure loaded on the first stage catalyst modifies the surface of the alumina support, reducing the number of hydroxyl groups and the isoelectric point of the support, weakening the interaction between the subsequently loaded active metal and the support, and promoting its moderate aggregation and growth on the surface of the heteropolyacid salt. The organic compounds such as citric acid, tartaric acid, and oxalic acid contained in the second stage impregnation solution also modulate the adsorption behavior of the secondary impregnated active metal species, acting as a kind of "template guide" and "structural confinement" for the active metal, thus forming a structure with a specific morphology.

[0058] The six catalysts prepared above were used to evaluate their hydrogenation activity on a 200ml scale. The feedstock was low-quality kerosene from a petrochemical company. The properties of the feedstock and the evaluation results of the examples are shown in Table 1, and the evaluation results of the comparative examples are shown in Table 2. As can be seen from Tables 1 and 2, compared with the two comparative examples, the hydrogenation activity of the catalysts in the examples is significantly improved, manifested in higher desulfurization and denitrification rates, and a greater increase in the aromatic saturation ratio and smoke point.

[0059] Table 1. Catalyst activity evaluation results of the examples.

[0060] Analysis Project raw material Example 1 Example 2 Example 3 Example 4 <![CDATA[Density, g / cm 3 (at 20 °C)]]> 0.8032 0.7945 0.7946 0.7942 0.7941 Distillation range, °C Initial boiling point 176 175 174 175 175 Final boiling point 245 244 244 242 244 Sulfur content, μg / g 4380 2.0 1.9 2.1 2.0 Nitrogen content, μg / g 19.0 0.5 0.4 0.5 0.5 Smoke point, mm 20.5 27.6 27.4 27.5 27.3 Total aromatics, v% 20.9 8.4 8.3 8.0 8.5

[0061] Table 2. Catalyst activity evaluation results for comparative examples

[0062]

[0063]

[0064] Note: (1) Sulfidation conditions: The catalyst is first pre-sulfided for 20 hours in a hydrogen atmosphere at 330°C with kerosene containing 2ω% carbon disulfide at a pressure of 7.0 MPa, and then fed into the raw material;

[0065] (2) Reaction conditions: reaction temperature 322℃, pressure 6.0MPa, space velocity (volume) 1.8h -1 The hydrogen-to-oil (volume) ratio is 300.

[0066] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a catalyst with hydrodesulfurization, denitrogenation, and aromatic saturation properties, characterized in that, include: Using γ-Al2O3 or γ-Al2O3 modified with additives as a support, a first impregnation solution containing heteropoly acid salts is impregnated. After drying, a first-stage catalyst semi-finished product is obtained. Then, a second impregnation solution containing active metals is impregnated. After drying and calcination, the catalyst finished product is obtained. The heteropoly acid salt is Ni6[WM3(H2O)2(MW9O 34 )2], M is one or more of Fe, Zn, Cu, and Co; the second impregnation solution is a stable solution containing two active metals, W and Ni.

2. The method for preparing the catalyst with hydrodesulfurization, denitrogenation and aromatic saturation properties according to claim 1, characterized in that, The second impregnation solution also contains one or more of citric acid, tartaric acid, and oxalic acid.

3. The method for preparing the catalyst with hydrodesulfurization, denitrogenation and aromatic saturation properties according to claim 1, characterized in that, The first impregnation solution also contains one or more of C1 to C8 alcohols.

4. The method for preparing the catalyst with hydrodesulfurization, denitrogenation and aromatic saturation properties according to claim 3, characterized in that, The C1-C8 alcohols are methanol, ethanol, ethylene glycol, propanol, glycerol, butanol, butanediol, pentanol, hexanol, octanol, and methylcyclohexanol.

5. The method for preparing the catalyst with hydrodesulfurization, denitrogenation and aromatic saturation properties according to claim 3, characterized in that, The mass ratio of heteropolyacid salts to C1-C8 alcohols in the first impregnation solution is (78-95):(5-22).

6. The method for preparing the catalyst with hydrodesulfurization, denitrogenation and aromatic saturation properties according to claim 1, characterized in that, The roasting conditions are 300℃~600℃ for 2h~20h.

7. The method for preparing the catalyst with hydrodesulfurization, denitrogenation and aromatic saturation properties according to claim 1, characterized in that, The γ-Al2O3 modified by the additive is Si and Ti modified γ-Al2O3.

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