A preparation method of a hydrofining catalyst

Abstract

The present invention discloses a preparation method of a hydrofining catalyst. The preparation method of the hydrofining catalyst of the present invention includes the following contents: (1) A solution containing W, Mo, and Al and a precipitating agent are added into a reaction tank in a co-current manner for gelation reaction. After the reaction, a random polyether polyoxyethylene-polyoxypropylene copolymer is added to obtain a slurry; (2) A solution containing Ni and a precipitating agent are dropped into the slurry, and then aged. During the aging process, a solution containing Al is added in 2 to 8 times, and the slurry obtained after aging is filtered; (3) The material obtained in step (2) is subjected to first drying, forming, washing, and then second drying and calcination to obtain a hydrofining catalyst. The hydrofining catalyst prepared by this method has a stepped pore size distribution, a special active phase morphology and distribution, a large surface phase active site density, and has high hydro-saturation reaction performance, and is particularly suitable for use in the hydrodearomatization of heavy distillate oil, ultra-deep hydrodesulfurization, and denitrification reactions.

Description

Technical Field

[0001] The present invention belongs to the field of catalyst preparation, and particularly relates to a method for preparing a hydrofining catalyst for distillate oil. Background Art

[0002] Traditional supported hydrocatalysts are restricted by the pore structure of the support. Generally, the loading amount of active metal does not exceed 30 wt%. The number of active centers provided by the supported catalyst is limited and cannot meet the requirement of significantly reducing the aromatic content in catalytic diesel. Bulk catalysts are currently the hydrocatalysts with the highest activity, and the content of active metal reaches more than 70%. Bulk hydrocatalysts can get rid of the limitation of metal content, can arbitrarily adjust the proportion of each active component in the catalyst, and improve the hydrogenation performance of the catalyst. The combination of active metal components in the hydrocatalyst has better activity than individual components. Among the combinations of metal components, the W-Ni combination has the best hydrogenation saturation activity, and the Mo-Ni combination has the best hydrodenitrogenation property.

[0003] During the hydrotreating reaction of distillate oil, reactant molecules pass through the catalyst pores and react on the surface of the catalyst they contact. The catalyst needs to have a larger pore size to facilitate the smooth passage of macromolecular reactants through the catalyst pores, which can reduce the inhibitory effect of macromolecular nitrides on the hydrodesulfurization reaction. Although the content of active metal in the bulk hydrocatalysts prepared by existing methods is high, the surface area of the catalyst is small, the active metal is unevenly dispersed, and at the same time, the disordered distribution of different hydrogenation active metals results in no good coordination effect between active metals. The high content of metals in the bulk catalyst is prone to excessive accumulation of metal particles, reducing the formation of active phases, making the active metal unable to become a hydrogenation active center, affecting the utilization rate of the active metal of the catalyst, and also increasing the use cost of the catalyst.

[0004] CN1951561A discloses a method for preparing a hydrocatalyst by coprecipitation. The catalyst uses active metal Ni, W components and a precipitant to coprecipitate in parallel to generate Ni x W y O z composite oxide precursor. In the above process, an aluminum salt solution can be added, or aluminum hydroxide can be directly added after gelling, and then mixed with MoO 3 by pulping, filtering, shaping, and activating to obtain the final catalyst. In the method for preparing the bulk catalyst, the active metal is excessively accumulated, reducing the utilization rate of the active metal.

[0005] CN101306374A discloses a hydrogenation catalyst composition. A compound of at least one Group VIII metal component, compounds of at least two Group VIB metal components, an organic additive and water are mixed to prepare a mixed solution. The obtained mixed solution is placed in a reaction kettle and reacted for 1 to 24 hours under sealed conditions at room temperature to 250 °C, followed by filtration and drying to obtain the finished catalyst. The catalysts obtained by this method have uneven distribution of different hydrogenation active metals, resulting in a decrease in catalyst activity.

[0006] CN101255356A discloses a preparation method of a non-supported catalyst. The urea melting reaction technology is adopted. The active metal precursors containing Group VIII and Group VIB are mixed with urea and reacted under the molten state of urea, and the excess urea is removed to obtain catalyst particles, which can be formed by adding a binder. In this method, urea is added as a precipitant. After the reaction, it is necessary to heat to remove the excess urea, and then add a binder for forming. As a result, the catalyst prepared by this method has uneven pore size distribution and poor catalyst crush strength.

[0007] CN106179380A discloses a bulk-phase hydrofining catalyst and its preparation method. In this method, the nickel-aluminum mixed precipitate is prepared by the positive addition method, and the tungsten, molybdenum and aluminum mixed precipitate is prepared by the co-current precipitation method. Then the two are mixed, aged, filtered, and the obtained metal mixture is subjected to steam treatment under suitable conditions and urea is added. The material after hydrothermal treatment is dried, formed and calcined to obtain the catalyst. The surface active metal content in the bulk-phase catalyst obtained by this method is high, but the catalyst pore distribution is uneven, the surface pore size of the catalyst is small, and the surface active metals are excessively stacked, without improving the utilization rate of the surface active metals.

[0008] CN106513006A discloses a preparation method of a bulk-phase hydrofining catalyst. The method includes: mixing a Ni compound with deionized water for pre-dispersion under an ultrasonic environment, then adding a Mo compound to form a Ni-Mo fine grain structure, then adding a W compound and a complexing agent for hydrothermal reaction, and then kneading the obtained active component powder with aluminum hydroxide dry gel, extruding, drying and calcining to obtain the catalyst. The catalysts prepared by the method of the present invention have uniform dispersion among different active phase grains, high utilization rate of active metals, excellent pore structure properties, and improved removal efficiency of complex sulfur compounds in inferior diesel. However, the active metals in the bulk-phase catalyst are not fully utilized, the amount of surface active metals is not much, the hydrodenitrogenation activity is not improved, and the removal efficiency of complex sulfur compounds with high nitrogen content is limited.

[0009] CN109692686A discloses a hydrofining catalyst and a preparation method thereof. The hydrofining catalyst is a bulk hydrofining catalyst. First, a mixed solution A containing Ni, W, and Al components and a precipitant are reacted in a parallel flow manner, and the obtained slurry is aged. Then, a mixed solution B containing W and Al components, a precipitant, and MoO 3 The slurry is added to the above-aged slurry in a parallel flow manner, and then aged again. Then, it is made into a hydrofining catalyst through steps such as drying and shaping. After the catalyst is sulfided, the average stacking layer number of MoS 2 / WS 2 is relatively large, and the specific surface area and pore volume of the catalyst are relatively small, resulting in a relatively short average lamellar length of MoS 2 / WS 2 This catalyst has relatively high hydrodesulfurization and hydrodenitrogenation reaction activities, but the aromatic saturation performance for treating heavy oil has not been significantly improved.

[0010] In the existing technology of preparing bulk catalysts by coprecipitation method, different precipitation methods and gel-forming conditions will all affect the pore size distribution of the catalyst. Different pore size distributions will affect the distribution of hydrogenation active metals on the surface of the bulk catalyst. How to increase the content of surface active metals and the density of active centers in the catalyst, improve the utilization rate of surface hydrogenation active metal components, and match the distribution of active metals in the catalyst with the pore structure is the key to improving the hydrogenation performance of bulk hydrofining catalysts. Summary of the Invention

[0011] Aiming at the deficiencies of the existing technology, the present invention provides a preparation method of a hydrofining catalyst. The catalyst prepared by this method is a bulk hydrofining catalyst, which has a stepped pore size distribution, a special active phase morphology and distribution, a large density of surface active sites, and relatively high hydrogenation saturation reaction performance, and is particularly suitable for applications in hydrodearomatization of heavy distillate oil, ultra-deep hydrodesulfurization, and denitrification reactions.

[0012] The preparation method of the hydrofining catalyst of the present invention includes the following steps: (1) A solution containing W, Mo, and Al and a precipitant are added to a reaction tank in a parallel flow manner for gel-forming reaction. After the reaction, a random polyether polyoxyethylene-polyoxypropylene copolymer is added to obtain slurry I; (2) A solution containing Ni and a precipitant are dropped into slurry I obtained in step (1), and gel-forming reaction is carried out for a period of time to obtain slurry II. Slurry II is continuously aged n times, and 1 / n of the solution containing Al is added during each aging process. The aged slurry III is filtered to obtain a solid phase material; (3) The solid phase material obtained in step (2) is subjected to first drying, shaping, washing, and then second drying and calcination to obtain a hydrofining catalyst.

[0013] In the method of the present invention, in the solution containing W, Mo, and Al in step (1), W is in the form of WO 3The weight concentration is 5 to 120 g / L, preferably 10 to 110 g / L, and Mo is in the form of MoO 3 The weight concentration is 5 to 110 g / L, preferably 10 to 100 g / L, and Al is Al 2 O 3 The weight concentration is 2 to 90 g / L, preferably 6 to 85 g / L; wherein, when preparing a solution containing W, Mo, and Al, the tungsten source generally used is ammonium metatungstate, the molybdenum source is ammonium molybdate, and the aluminum source is one or more of aluminum nitrate, aluminum sulfate, aluminum chloride, and aluminum acetate.

[0014] In the method of the present invention, the conditions for the gelling reaction in step (1) are: the reaction temperature is 30 to 95° C., preferably 40 to 95° C., the pH value of the co-current reaction is controlled at 5 to 6, and the reaction time is 0.1 to 1.0 hour.

[0015] In the method of the present invention, the random polyether polyoxyethylene-polyoxypropylene copolymer described in step (1) is selected from one or more of isomeric tridecanol random polyether TPE-1000, propylene glycol random polyether PPE-1500, glycerol random polyether GPE-3000, butanol random polyether BPE-1000, butanol random polyether BPE-1500, butanol random polyether BPE-2500, lauric acid random polyether LPE-1200 and dodecanol random polyether CPE-1500. The molar ratio of the random polyether polyoxyethylene-polyoxypropylene copolymer to W is 0.2-1.8, preferably 0.3-1.5.

[0016] In the method of the present invention, in the Ni-containing solution of step (2), the weight concentration of Ni in terms of NiO is 5 to 130 g / L, preferably 10 to 115 g / L; in the Al-containing solution, the weight concentration of Al in terms of Al 2 O 3 The weight concentration is 5 to 70 g / L, preferably 8 to 60 g / L. When preparing a solution containing Ni, the general nickel source is one or more of nickel sulfate, nickel nitrate, and nickel chloride; when preparing a solution containing Al, the general aluminum source is a soluble aluminum salt, such as one or more of aluminum nitrate, aluminum sulfate, and aluminum chloride.

[0017] In the method of the present invention, the precipitants described in steps (1) and (2) are both alkaline precipitants, selected from one or more of sodium carbonate, sodium bicarbonate, ammonia water, sodium hydroxide, potassium hydroxide, potassium carbonate or potassium bicarbonate, preferably ammonia water and sodium hydroxide solution, wherein the concentration of ammonia water is 5wt% to 15wt%, and the concentration of sodium hydroxide solution is 7wt% to 20wt%.

[0018] In the method of the present invention, the conditions of the gelation reaction in step (2) are as follows: the reaction temperature is 30-95 °C, preferably 40-95 °C, the pH value at the end is controlled at 8.0-12.0, and the reaction time is 0.5-2.5 hours; preferably, the temperature of the reaction in step (2) is the same as the temperature of the reaction in step (1).

[0019] In the method of the present invention, the Al-containing solution in step (2) is divided into 2-8 parts by volume according to the number of additions, preferably divided equally by volume.

[0020] In the method of the present invention, in step (2), the slurry is preferably subjected to n times of three-stage decreasing pH aging continuously, and 1 / n of the Al-containing solution is added each time at the end of the first-stage pH aging; the specific process of each three-stage decreasing pH aging is as follows: the aging temperature of each stage is 60-98 °C, preferably 65-92 °C; in the first stage, the pH value is 11.0-13.5, and the aging time is 0.05-0.5 hours. After the aging ends, 1 / n of the Al-containing solution is added. In the second stage, the pH value is adjusted to 8.5-10.5, and the aging time is 0.05-0.5 hours. In the third stage, the pH value is adjusted to 5.5-8.3, and the aging time is 0.05-0.5 hours; and so on (that is, the pH value is controlled to be 11.0-13.5 again, and the aging time is 0.05-0.5 hours, where n is an integer from 2 to 8).

[0021] Among them, the acids and bases used to adjust the pH value during the aging process can be inorganic salts, inorganic acids, and inorganic bases that do not contain aluminum elements. The inorganic acids can be hydrochloric acid and acetic acid, and the inorganic bases can be one or more of sodium carbonate, sodium bicarbonate, ammonia water, and sodium hydroxide. The concentration and dosage of the acid and base solutions can be adjusted according to the actual preparation needs.

[0022] In the method of the present invention, in step (2), the Al added through the Al-containing solution accounts for 5%-55% of the total Al in the obtained hydrofining catalyst in terms of Al 2 O 3 calculated, preferably 6%-50%.

[0023] In the method of the present invention, the first drying, shaping, and washing described in step (3) can be carried out by conventional methods in the art. The conditions for the first drying are as follows: drying at 40~150°C for 1~48 hours, preferably drying at 50~120°C for 4~36 hours. During the shaping process, conventional shaping aids can be added as needed, such as one or more of peptizing agents, extrusion aids, etc. The peptizing agent is one or several of hydrochloric acid, nitric acid, sulfuric acid, acetic acid, oxalic acid, etc. The extrusion aid refers to substances that are beneficial for extrusion shaping, such as one or several of sesbania powder, carbon black, graphite powder, citric acid, etc. The dosage of the extrusion aid accounts for 1wt%~10wt% of the total dry basis of the material. Washing is generally carried out with deionized water or a solution containing decomposable salts (such as ammonium acetate, ammonium chloride, ammonium nitrate, etc.) until neutral.

[0024] The drying conditions for the second drying described in step (3) are as follows:

[0025] a. First, dry the material at 60~100°C for 1.0~8.5 hours, preferably dry at 70~90°C for 2.0~8.0 hours;

[0026] b. Uniformly spray water (preferably deionized water) on the material obtained in step a. The volume ratio of the added water to the volume of the dried material is 1:4~4:1. Then, carry out drying at a temperature of 150~280°C, preferably 150~250°C, and the drying time is 0.5~4.0 hours, preferably 0.6~3.5 hours;

[0027] c. Repeat the process of step b 2~9 times, preferably 3~8 times.

[0028] Among them, the volume ratio of the first added water to the volume of the dried material is greater than 1:1, and the volume ratio of the last added water to the volume of the dried material is less than 1:1. Further, the volume ratio of the added water to the volume of the dried material decreases successively with the increase in the number of drying times.

[0029] Further, the total drying time for the second drying is preferably 5~40 hours, and more preferably 7~38 hours.

[0030] In the method of the present invention, the roasting conditions described in step (3) are as follows: roasting at 350~650°C for 1~24 hours, preferably roasting at 400~600°C for 2~12 hours.

[0031] The present invention also provides a hydrofining catalyst which is a bulk-phase hydrofining catalyst. The hydrofining catalyst comprises a composite oxide of W, Mo, Ni and Al. The catalyst particles include an outer surface layer, an intermediate layer and a central core, and the average pore diameter decreases in a gradient, that is, the average pore diameter of the outer surface layer is larger than that of the intermediate layer, and the average pore diameter of the intermediate layer is larger than that of the central core. The average pore diameter of the outer surface layer is 10-18 nm, the average pore diameter of the intermediate layer is 7-10 nm, and the average pore diameter of the central core is 3-7 nm. Wherein, on the cross-section of the catalyst particle, the length from the outermost edge to the center point is R; the thickness of the outer surface layer is 0.2R-0.4R, the thickness of the intermediate layer is 0.2R-0.5R, and the rest is the central core; the molar ratio of W / Mo is 1:12-10:1, preferably 1:10-8:1, and the molar ratio of Ni / (Mo + W) is 1:12-12:1, preferably 1:10-10:1; wherein the sum of the weight contents of the surface-phase active metal components WO 3 and NiO and the sum of the weight contents of the bulk-phase active metal components WO 3 and NiO is in the ratio of 2.0:1-5.5:1, preferably 2.5:1-5.0:1. The sum of the weight contents of the surface-phase active metal components MoO 3 and NiO and the sum of the weight contents of the bulk-phase active metal components MoO 3 and NiO is in the ratio of 1.8:1-4.5:1, preferably 2.0:1-4.0:1. The catalyst of the present invention is in the form of (solid) particles, and the average pore diameter decreases from the outer surface layer to the central core of the catalyst.

[0032] In the hydrofining catalyst, based on the weight of the hydrofining catalyst, the total content of Ni, W and Mo in terms of oxides is 35%-95%, preferably 50%-90%, and the alumina content is 5%-65%, preferably 10%-50%.

[0033] The properties of the hydrofining catalyst are as follows: the specific surface area is 200-500 m 2 / g, and the pore volume is 0.25-1.0 mL / g.

[0034] The catalyst of the present invention can be prepared by a conventional forming method, and the shape can be various shapes commonly used for hydrofining catalysts, such as cylindrical, spherical, etc. The spherical shape can be spherical, ellipsoidal, etc., and the cylindrical shape can be cylindrical, square-columnar or columnar with a special cross-section (such as clover, four-leaf clover, etc.). The particle size of the catalyst particles is 1-10 mm. Generally, when it is cylindrical, the length can be 2-10 mm, and the particle size can be 1-6 mm. Generally, when it is spherical, the particle size is 2-10 mm.

[0035] Use of the hydrofining catalyst of the present invention in the ultra-deep hydrodesulfurization, denitrification reaction and hydrodearomatization of heavy diesel fractions, wherein the aromatic content in the heavy diesel fraction is 50 wt% to 85 wt%, and the cetane number is less than 24.

[0036] Compared with the prior art, the present invention has the following advantages:

[0037] In the present invention, a solution containing W, Mo, and Al is first precipitated, and a solution containing Ni is added dropwise to the obtained slurry at a specific pH value. This specific addition sequence, corresponding pH value control, different active metal precipitation sequences, addition of organic additives, and addition of the solution containing Al in portions during aging result in a significant increase in the distribution of the hydroactive metals tungsten, nickel, and molybdenum in the surface phase, and they are more uniformly dispersed, which is beneficial to increasing the density of the surface active sites of the combined tungsten and nickel and the combined molybdenum and nickel of the active metals. At the same time, adding the solution containing Al in portions can not only increase the active metals in the surface phase of the catalyst, but also increase the macropores in the bulk catalyst, making it easier for large molecule reactants to pass through the pores, further optimizing the pore size distribution and active metal dispersion of the obtained catalyst, and strengthening the promotion effect between the active metals. When the drying method used for the second drying after forming is adopted, in the pore distribution of the catalyst particles, from the outer surface layer to the central core of the catalyst, the average pore diameter decreases from large to small. This can weaken the influence of the diffusion effect when reactants such as large molecules with larger molecular diameters enter and exit the catalyst pores, which is beneficial to improving the diffusion performance of the catalyst for large molecules, improving the hydrogenation of reactants such as large molecules with larger molecular diameters by the tungsten, nickel, and molybdenum active metals in the surface phase of the catalyst, effectively utilizing the high-density active metals in the surface phase of the bulk catalyst, and reducing the inhibitory effect of nitrogen compounds on the hydrodesulfurization reaction. The catalyst drying method further improves the interaction between metal components, which is beneficial to generating more active hydrogenation active centers. Through the comprehensive control of the preparation steps and preparation conditions, the surface phase of the obtained bulk catalyst has a high hydrogenation active site and a hierarchical pore distribution, improving the hydrogenation activity for treating heavy oil, especially being beneficial to the aromatic saturation of heavy oil, effectively reducing the content of polycyclic aromatic hydrocarbons, and increasing the cetane number. The hydrofining catalyst prepared by the method of the present invention has high hydrodesulfurization, hydrodenitrification, and aromatic saturation reaction performances, and is particularly suitable for use in the ultra-deep hydrodesulfurization, denitrification, and hydrodearomatization reactions of diesel fractions. Detailed implementation mode

[0038] In the present invention, the specific surface area and pore volume are measured by the low-temperature liquid nitrogen adsorption method, and the mechanical strength is measured by the side pressure method.

[0039] In the present invention, the content of the active metal in the surface phase of the catalyst is measured by X-ray photoelectron spectroscopy (XPS), and the content of the active metal in the bulk phase of the catalyst is measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES).

[0040] In the present invention, wt% represents mass fraction and v% represents volume fraction.

[0041] In the present invention, the "cross-section of the catalyst particle" refers to the entire surface exposed after cutting through the geometric center of its shape along the direction of the minimum dimension of a catalyst particle. For example, when the catalyst particle is spherical, the cross-section refers to the entire surface exposed after cutting through the center of the sphere along the radius or minor axis of the sphere. Alternatively, when the catalyst particle is columnar, the cross-section refers to the entire surface exposed after cutting through the center point of the length dimension perpendicular to the length dimension direction of the column. The outer periphery of the exposed surface is called the outermost edge of the cross-section, and the geometric center (such as the center of the sphere or the center point of the length dimension mentioned above) is called the center point of the cross-section.

[0042] In the present invention, for the method of measuring the average pore diameter of different layers from the outer surface layer to the central core of the catalyst particle: First, use the low-temperature nitrogen adsorption method (BET) to measure the pore volume, specific surface area, and average pore diameter of the sample. Then, take a certain amount of the sample and place it in a catalyst attrition tester, and polish the sample while adding a certain amount of quartz sand to increase the wear rate. When the particle size of the sample decreases to a certain extent after polishing, measure the weight loss of the sample and measure its pore structure again. From the relationship that the total pore volume and specific surface area of the sample are equal to the sum of each part, the pore volume and specific surface area of the polished part can be calculated. At the same time, measure 20 - 80 samples, and then calculate the average pore diameter. Thus, the average pore diameter of different layers from the outer surface layer to the central core is measured.

[0043] Example 1

[0044] Ammonium metatungstate, ammonium molybdate, and aluminum chloride were respectively added to the dissolution tank 1 filled with deionized water to prepare a solution containing W, Mo, and Al. In the solution containing W, Mo, and Al, the weight concentration of W calculated as WO 3 was 60 g / L, the weight concentration of Mo calculated as MoO 3 was 40 g / L, and the weight concentration of Al calculated as Al 2 O 3 was 36.4 g / L. Nickel chloride was added to the dissolution tank 2 filled with deionized water to prepare a solution containing Ni. In the solution containing Ni, the weight concentration of Ni calculated as NiO was 48 g / L. Aluminum chloride was added to the dissolution tank 3 filled with deionized water to prepare a solution containing Al. The Al in the solution containing Al accounted for the total Al in the obtained hydrofining catalyst (calculated as Al 2 O 330% of it (calculated based on [specific content not provided]), and divide it into 4 equal parts by volume. Add deionized water to the reaction tank, and add the solution containing W, Mo, and Al and sodium hydroxide solution (weight concentration of 10%) into the reaction tank in parallel for gelation reaction. Control the reaction pH value at 5.3, the reaction temperature at 60 °C. After reacting for 0.5 hours, add random polyether of isomeric tridecanol TPE-1000 to the reaction tank. The molar ratio of the random polyether of isomeric tridecanol TPE-1000 to W in the solution containing W, Mo, and Al is 0.8. After stirring evenly, then add the solution containing Ni and sodium hydroxide solution (weight concentration of 10%) dropwise into the reaction slurry simultaneously. The reaction temperature remains unchanged, and the reaction time is 1.0 hour. Control the pH value at 8.9 at the end of the reaction to generate a precipitate slurry containing nickel, molybdenum, tungsten, and aluminum. Age the obtained slurry. The aging temperature is 76 °C. First, control the pH value during aging at 13.1. After aging for 0.2 hours, add one part of the solution containing Al, and then control the aging pH value at 9.7. After aging for 0.3 hours, then control the pH value at 7.7, and the aging time is 0.2 hours. Repeat the above operation process 4 times to end the aging. Filter the aged slurry, dry the filter cake at 100 °C for 8 hours, roll it, and extrude it into strips. Wash it with deionized water at room temperature until neutral. Then dry the washed wet strips as follows: First, dry the material at 80 °C for 6.0 hours. Sprinkle deionized water evenly on the dried material, and then dry it. Repeat the process of evenly sprinkling deionized water and drying 5 times. The volume ratio of the first sprinkling of deionized water to the dried material is 2:1, the drying temperature is 170 °C, and the drying time is 2.5 hours. The volume ratio of the second sprinkling of deionized water to the dried material is 1.5:1, the drying temperature is 180 °C, and the drying time is 2.5 hours. The volume ratio of the third sprinkling of deionized water to the dried material is 1:1, the drying temperature is 180 °C, and the drying time is 2.0 hours. The volume ratio of the fourth sprinkling of deionized water to the dried material is 1:2, the drying temperature is 180 °C, and the drying time is 2.0 hours. The volume ratio of the fifth sprinkling of deionized water to the dried material is 1:3, the drying temperature is 260 °C, and the drying time is 2.0 hours. Calcine the dried material at 530 °C for 5 hours to obtain catalyst A. The catalyst composition and main properties are shown in Table 1.

[0045] Example 2

[0046] Add ammonium metatungstate, ammonium molybdate, and aluminum chloride into dissolution tank 1 filled with deionized water respectively to prepare a solution containing W, Mo, and Al. In the solution containing W, Mo, and Al, W is in the form of WO 3 with a weight concentration of 52 g / L calculated based on [specific content not provided], Mo is in the form of MoO 3 with a weight concentration of 44 g / L calculated based on [specific content not provided], and Al is in the form of Al 2 O 3The calculated weight concentration is 35.4 g / L. Nickel chloride is added to the dissolution tank 2 filled with deionized water to prepare a mixed Ni-containing solution. The weight concentration of Ni in the Ni-containing solution in terms of NiO is 52 g / L. Aluminum chloride is added to the dissolution tank 3 filled with deionized water to prepare an Al-containing solution. Al in the Al-containing solution accounts for Al in the resulting hydrofining catalyst (in terms of Al 2 O 332% of the total amount (calculated), and it is divided into 5 equal parts by volume. Deionized water is added to the reaction tank, and the solution containing W, Mo, and Al and the sodium hydroxide solution (weight concentration of 12%) are fed into the reaction tank in parallel for gelation reaction. The reaction pH value is controlled at 5.8, the reaction temperature is 65 °C. After reacting for 0.8 hours, glycerol random polyether GPE-3000 is added to the reaction tank. The molar ratio of glycerol random polyether GPE-3000 to W in the solution containing W, Mo, and Al is 0.8. After stirring evenly, the solution containing Ni and the sodium hydroxide solution (weight concentration of 12%) are simultaneously dropped into the reaction slurry. The reaction temperature remains unchanged, and the reaction time is 0.9 hours. At the end of the reaction, the pH value is controlled at 8.5 to form a precipitate slurry containing nickel, molybdenum, tungsten, and aluminum. The obtained slurry is aged. The aging temperature is 80 °C. The pH value during aging is first controlled at 12.8. After aging for 0.25 hours, 1 equal part of the solution containing Al is added, and then the aging pH value is controlled at 9.3. After aging for 0.2 hours, the pH value is then controlled at 6.9, and the aging time is 0.2 hours. The above operation process is repeated 5 times to end the aging. The aged slurry is filtered, and the filter cake is dried at 80 °C for 12 hours, rolled, and extruded into strips. It is washed with deionized water at room temperature until neutral. Then the washed wet strips are dried as follows: First, the material is dried at 75 °C for 6.0 hours. Deionized water is evenly sprayed on the dried material, and then dried. The process of evenly spraying deionized water and drying is repeated 7 times. The volume ratio of the first spraying of deionized water to the dried material is 2.0:1, the drying temperature is 190 °C, and the drying time is 2.2 hours. The volume ratio of the second spraying of deionized water to the dried material is 1.5:1, the drying temperature is 170 °C, and the drying time is 2.0 hours. The volume ratio of the third spraying of deionized water to the dried material is 1.2:1, the drying temperature is 190 °C, and the drying time is 1.8 hours. The volume ratio of the fourth spraying of deionized water to the dried material is 1:1.2, the drying temperature is 180 °C, and the drying time is 1.5 hours. The volume ratio of the fifth spraying of deionized water to the dried material is 1:1.6, the drying temperature is 180 °C, and the drying time is 1.5 hours. The volume ratio of the sixth spraying of deionized water to the dried material is 1:2.0, the drying temperature is 180 °C, and the drying time is 2 hours. The volume ratio of the seventh spraying of deionized water to the dried material is 1:2.5, the drying temperature is 170 °C, and the drying time is 1.6 hours. The washed wet strips are dried at 80 °C for 12.0 hours. The dried material is calcined at 540 °C for 5 hours to obtain catalyst B. The catalyst composition and main properties are shown in Table 1.

[0047] Example 3

[0048] Ammonium metatungstate, ammonium molybdate, and aluminum chloride are respectively added to the dissolution tank 1 filled with deionized water to prepare a solution containing W, Mo, and Al. In the solution containing W, Mo, and Al, W is in the form of WO 3The calculated weight concentration is 48 g / L, and Mo is in the form of MoO 3 The calculated weight concentration is 36 g / L, and Al is in the form of Al 2 O 3 The calculated weight concentration is 39 g / L. Nickel chloride is added to the dissolution tank 2 filled with deionized water to prepare a solution containing Ni. The weight concentration of Ni in the solution containing Ni is 64 g / L in terms of NiO. Aluminum chloride is added to the dissolution tank 3 filled with deionized water to prepare a solution containing Al. Al in the solution containing Al accounts for 25% of Al (in terms of Al 2 O 3 in the resulting hydrofining catalyst), and it is divided into 4 equal parts by volume. Deionized water is added to the reaction tank, and the solutions containing W, Mo, Al and ammonia water (weight concentration of 11%) are added to the reaction tank in parallel for gelation reaction. The reaction pH value is controlled at 5.4, the reaction temperature is 55 °C. After reacting for 0.7 hours, polypropylene glycol random polyether PPE-1500 is added to the reaction tank. The molar ratio of polypropylene glycol random polyether PPE-1500 to W in the solution containing W, Mo, Al is 0.6. After stirring evenly, the solution containing Ni and ammonia water (weight concentration of 11%) are simultaneously dropped into the reaction slurry. The reaction temperature remains unchanged, and the reaction time is 1.0 hour. At the end of the reaction, the pH value is controlled at 9.2 to form a precipitate slurry containing nickel, molybdenum, tungsten, and aluminum. The obtained slurry is aged. The aging temperature is 83 °C. The pH value during aging is first controlled at 12.8. After aging for 0.2 hours, 1 part of the solution containing Al is added, and then the aging pH value is controlled at 9.6. After aging for 0.1 hours, the pH value is then controlled at 7.1, and the aging time is 0.2 hours. The above operation process is repeated 4 times to end the aging. The aged slurry is filtered, and the filter cake is dried at 100 °C for 8 hours, rolled, and extruded into strips. It is washed with deionized water at room temperature until neutral. Then the washed wet strips are dried at 90 °C for 9.0 hours. Then the washed wet strips are dried as follows: First, the material is dried at 78 °C for 6.5 hours. Deionized water is evenly sprayed on the dried material, and then dried. The process of evenly spraying deionized water and drying is repeated 5 times. The volume ratio of the first spraying of deionized water to the dried material is 1.4:1, the drying temperature is 200 °C, and the drying time is 2.3 hours. The volume ratio of the second spraying of deionized water to the dried material is 1.0:1, the drying temperature is 180 °C, and the drying time is 2.1 hours. The volume ratio of the third spraying of deionized water to the dried material is 1:1.2, the drying temperature is 190 °C, and the drying time is 1.7 hours. The volume ratio of the fourth spraying of deionized water to the dried material is 1:1.5, the drying temperature is 180 °C, and the drying time is 1.8 hours. The volume ratio of the fifth spraying of deionized water to the dried material is 1:2.0, the drying temperature is 180 °C, and the drying time is 1.7 hours. The dried material is calcined at 510 °C for 5 hours to obtain catalyst C. The catalyst composition and main properties are shown in Table 1.

[0049] Example 4

[0050] Ammonium metatungstate, ammonium molybdate and aluminum chloride were respectively added to the dissolution tank 1 filled with deionized water to prepare a solution containing W, Mo and Al. In the solution containing W, Mo and Al, the weight concentration of W calculated as WO 3 was 56 g / L, the weight concentration of Mo calculated as MoO 3 was 30 g / L, and the weight concentration of Al calculated as Al 2 O 3 was 38 g / L. Nickel chloride was added to the dissolution tank 2 filled with deionized water to prepare a solution containing Ni. In the solution containing Ni, the weight concentration of Ni calculated as NiO was 56 g / L. Aluminum chloride was added to the dissolution tank 3 filled with deionized water to prepare a solution containing Al. The Al in the solution containing Al accounted for the total Al in the obtained hydrofining catalyst (calculated as Al 2 O 338% of the total amount (calculated as such), and it was divided into 6 equal parts by volume. Deionized water was added to the reaction tank, and the solution containing W, Mo, and Al and ammonia water (weight concentration of 10%) were added to the reaction tank in a co-current manner for gelation reaction. The reaction pH value was controlled at 5.2, the reaction temperature was 68 °C. After reacting for 0.4 hours, random polyether lauric acid LPE-1200 was added to the reaction tank. The molar ratio of random polyether lauric acid LPE-1200 to W in the mixed solution B was 1.0. After stirring evenly, the solution containing Ni and ammonia water (weight concentration of 13%) were simultaneously dropped into the reaction slurry. The reaction temperature remained unchanged, and the reaction time was 0.9 hours. At the end of the reaction, the pH value was controlled at 9.5 to form a precipitate slurry containing nickel, molybdenum, tungsten, and aluminum. The obtained slurry was aged. The aging temperature was 80 °C. The pH value during aging was first controlled at 12.5. After aging for 0.2 hours, 1 part of the solution containing Al was added, and then the aging pH value was controlled at 9.3. After aging for 0.15 hours, the pH value was then controlled at 7.0, and the aging time was 0.3 hours. The above operation process was repeated 6 times to end the aging. The aged slurry was filtered, and the filter cake was dried at 90 °C for 11 hours, rolled, and extruded into strips. It was washed with deionized water at room temperature until neutral. Then the washed wet strips were dried as follows: First, the material was dried at 75 °C for 7.0 hours. Deionized water was evenly sprayed on the dried material, and then it was dried. The process of evenly spraying deionized water and drying was repeated 5 times. The volume ratio of the first spraying of deionized water to the dried material was 1.7:1, the drying temperature was 180 °C, and the drying time was 2.1 hours. The volume ratio of the second spraying of deionized water to the dried material was 1.3:1, the drying temperature was 180 °C, and the drying time was 2.4 hours. The volume ratio of the third spraying of deionized water to the dried material was 1:1.2, the drying temperature was 170 °C, and the drying time was 2.2 hours. The volume ratio of the fourth spraying of deionized water to the dried material was 1:1.9, the drying temperature was 180 °C, and the drying time was 2.0 hours. The volume ratio of the fifth spraying of deionized water to the dried material was 1:2.3, the drying temperature was 160 °C, and the drying time was 2 hours. The dried material was calcined at 540 °C for 5 hours to obtain catalyst D. The catalyst composition and main properties are shown in Table 1.

[0051] Comparative Example 1

[0052] A reference agent E with the same catalyst composition as that in Example 1 of the present invention was prepared. The specific process is as follows:

[0053] Ammonium metatungstate, nickel chloride, ammonium molybdate, and aluminum chloride were respectively added to dissolution tank 1 filled with deionized water to prepare a mixed solution A. In the mixed solution A, the weight concentration of W calculated as WO 3 was 60 g / L, the weight concentration of Mo calculated as MoO 3 was 40 g / L, the weight concentration of Ni calculated as NiO was 48 g / L, and the weight concentration of Al calculated as Al2 O 3 The calculated weight concentration is 52 g / L. Deionized water is added to the reaction tank, and the mixed solution A and sodium hydroxide solution (weight concentration 10%) are added to the reaction tank in a concurrent flow for gelation reaction. The reaction pH value is controlled at 7.8, the reaction temperature is 60 °C, the reaction time is 1.5 hours, and a precipitate slurry containing nickel, molybdenum, tungsten, and aluminum is formed. The obtained slurry is aged at an aging temperature of 80 °C, with a pH value of 8.5 during aging and an aging time of 2.8 hours, and the aging is ended. The aged slurry is filtered, and the filter cake is dried at 100 °C for 8 hours, rolled, and extruded into pellets. It is washed with deionized water at room temperature until neutral. Then the washed wet pellets are dried at 100 °C for 10 hours. The dried material is calcined at 530 °C for 5 hours to obtain catalyst E. The catalyst composition and main properties are shown in Table 1.

[0054] Comparative Example 2

[0055] According to the preparation method disclosed in CN102451703A, a catalyst composition reference agent F for Example 1 of the present invention is prepared. The specific process is as follows:

[0056] Deionized water is added to dissolution tank 1, nickel chloride and ammonium metatungstate are added and dissolved respectively to prepare a mixed working solution A. In the mixed solution A, the weight concentration of W calculated as WO 3 is 60 g / L, and the weight concentration of Ni calculated as NiO is 48 g / L. Water is added to dissolution tank 2, and then sodium aluminate is added and dissolved to prepare an alkaline solution B. In the alkaline solution B, the weight concentration of Al calculated as Al 2 O 3 is 52 g / L. Deionized water is added to the reaction tank, and the temperature is raised to 60 °C. Under stirring, solution A, solution B, and CO 2 are added to the reaction tank in a concurrent flow for gelation. The concentration of CO 2 is 40 v%, the gelation temperature is 60 °C, the gelation time is 1.5 hours, and the pH value of the gelation slurry is 7.8. During the gelation process, the total amount of CO 2 gas added and the Al 2 O 3 in the alkaline solution have a molar ratio of 3.5. The aging temperature is 80 °C, the pH value during aging is 8.5, and aging is carried out for 2.8 hours after gelation. Then it is filtered, 600 ml of purified water and 40.3 g of molybdenum trioxide are added to the filter cake, and it is stirred evenly after pulping, filtered, the filter cake is dried at 100 °C for 8 hours, rolled, and extruded into pellets. It is washed with deionized water at room temperature until neutral. Then the washed wet pellets are dried at 100 °C for 10 hours. The dried material is calcined at 530 °C for 5 hours to obtain catalyst F. The catalyst composition and main properties are shown in Table 1.

[0057] Comparative Example 3

[0058] According to the preparation method disclosed in CN106179380A, a reference agent G with the same catalyst composition as that in Example 1 of the present invention was prepared. The specific process is as follows:

[0059] Nickel chloride and aluminum chloride solutions were respectively dissolved in deionized water to prepare a mixed solution A. The weight concentration of NiO in the mixed solution A was 48 g / L, and the weight concentration of Al 2 O 3 was 26 g / L. Ammonium metatungstate, ammonium molybdate and aluminum chloride solutions were respectively dissolved in deionized water to prepare a mixed solution B. The weight concentration of WO 3 in the mixed solution B was 60 g / L, the weight concentration of MoO 3 was 40 g / L, and the weight concentration of Al 2 O 3 was 26 g / L. A 10% (by weight) sodium hydroxide solution was added to solution A under stirring, and the gelling temperature was maintained at 60 °C. The pH value was controlled at 7.8 at the end, and the gelling time was controlled at 60 minutes to generate a nickel- and aluminum-containing precipitate slurry I. Deionized water was added to the reaction tank, and a 10% (by weight) sodium hydroxide solution and solution B were added to the reaction tank in parallel flow. The gelling temperature was maintained at 60 °C, and the pH value was controlled at 7.8 during the parallel-flow gelling reaction. The gelling time was controlled at 60 minutes to generate a tungsten-, molybdenum- and aluminum-containing precipitate slurry II. The above two precipitate-containing slurries were mixed and aged. The aging time was 2.8 hours, the aging temperature was 80 °C, and the pH value was controlled at 8.5. Then, filtration was carried out, and the filter cake was subjected to hydrothermal treatment under water vapor containing urea. The conditions for hydrothermal treatment were: the molar ratio of urea to the total amount of active metal atoms was 7:1, the temperature was 250 °C, the pressure was 4.0 MPa, and the treatment time was 3 hours. The filter cake was dried at 100 °C for 8 hours, rolled, extruded into shape, washed with deionized water to neutrality at room temperature, then dried at 100 °C for 10 hours and calcined at 530 °C for 5 hours to obtain catalyst G. The catalyst composition, pore distribution and main properties are shown in Table 1.

[0060] Comparative Example 4

[0061] According to the preparation method disclosed in CN106513006A, a reference agent H with the same catalyst composition as that in Example 1 of the present invention was prepared. The specific process is as follows:

[0062] Nickel basic carbonate was uniformly mixed with 300 ml of deionized water and then added into a 1 L high-pressure ultrasonic reactor. The ultrasonic frequency was set at 60 KHz, and the mixture was heated to 80 °C. After keeping the temperature constant for 1 h, the ultrasonic frequency was reduced to 20 KHz, and the system temperature was raised to 120 °C. Ammonium molybdate and polyvinylpyrrolidone were added. Then, 10 ml of 25 wt% ammonia water was gradually added dropwise into the system. After keeping the temperature constant for 2 h, the ultrasonic was turned off, and stirring was started at a speed of 300 revolutions per minute. Ammonium metatungstate was added, and then citric acid was added until the pH of the system reached 4.2. After keeping the temperature constant for 2 h, the heating was turned off. After the system cooled to room temperature, the slurry was collected and subjected to spray drying treatment. The inlet temperature and outlet temperature were controlled at about 200 °C and 100 °C respectively. The obtained dry powder was calcined in a muffle furnace at 330 °C for 3 h to obtain the active component powder. The active component powder was mixed with aluminum hydroxide dry gel accounting for 40% of the weight of the active component powder, and then 10% dilute nitric acid aqueous solution was added for kneading and extrusion to obtain a strip with a diameter of 1.5 mm. The strip was dried at 110 °C for 10 h and calcined in a muffle furnace at 400 °C for 5 h to obtain the reference agent H. The catalyst composition and main properties are shown in Table 1.

[0063] Comparative Example 5

[0064] Same as Example 1, prepare the reference agent I. During the preparation process, the random polyether polyoxyethylene-polyoxypropylene copolymer (isotridecanol random polyether TPE-1000) was not added.

[0065] Comparative Example 6

[0066] Same as Example 1, prepare the reference agent J. During the aging process of the precipitate slurry containing nickel, molybdenum, tungsten, and aluminum, all the Al solution was added at one time, and the aging pH value was a fixed value. The specific preparation process is as follows:

[0067] Ammonium metatungstate, ammonium molybdate, and aluminum chloride were respectively added into the dissolution tank 1 filled with deionized water to prepare a solution containing W, Mo, and Al. In the solution containing W, Mo, and Al, the weight concentration of W calculated as WO 3 was 60 g / L, the weight concentration of Mo calculated as MoO 3 was 40 g / L, and the weight concentration of Al calculated as Al 2 O 3 was 36.4 g / L. Nickel chloride was added into the dissolution tank 2 filled with deionized water to prepare a solution containing Ni. In the solution containing Ni, the weight concentration of Ni calculated as NiO was 48 g / L. Aluminum chloride was added into the dissolution tank 3 filled with deionized water to prepare a solution containing Al. The Al in the solution containing Al accounted for the total Al in the obtained hydrofining catalyst (calculated as Al 2 O 330% of the total amount (calculated as such). Deionized water was added to the reaction tank, and the solution containing W, Mo, and Al and the sodium hydroxide solution (weight concentration of 10%) were fed into the reaction tank in parallel for gelation reaction. The reaction pH value was controlled at 5.3, the reaction temperature was 60 °C. After reacting for 0.5 hours, the isomeric tridecyl alcohol random polyether TPE-1000 was added to the reaction tank. The molar ratio of the isomeric tridecyl alcohol random polyether TPE-1000 to W in the solution containing W, Mo, and Al was 0.8. After stirring evenly, the solution containing Ni and the sodium hydroxide solution (weight concentration of 10%) were simultaneously dropped into the reaction slurry. The reaction temperature remained unchanged, and the reaction time was 1.0 hour. At the end of the reaction, the pH value was controlled at 8.9 to form a precipitate slurry containing nickel, molybdenum, tungsten, and aluminum. The obtained slurry was aged. All the solution containing Al was added at the beginning of aging. The aging temperature was 76 °C, and the pH value during aging was controlled at 8.5. After aging for 2.8 hours, the aging was ended. The aged slurry was filtered, and the filter cake was dried at 100 °C for 8 hours, rolled, and extruded into strips. It was washed with deionized water at room temperature until neutral. Then the washed wet strips were dried as follows: First, the material was dried at 80 °C for 6.0 hours. Deionized water was evenly sprayed on the dried material, and then dried. The process of evenly spraying deionized water and drying was repeated 5 times. The volume ratio of the first spraying of deionized water to the dried material was 2:1, the drying temperature was 170 °C, and the drying time was 2.5 hours. The volume ratio of the second spraying of deionized water to the dried material was 1.5:1, the drying temperature was 180 °C, and the drying time was 2.5 hours. The volume ratio of the third spraying of deionized water to the dried material was 1:1, the drying temperature was 180 °C, and the drying time was 2.0 hours. The volume ratio of the fourth spraying of deionized water to the dried material was 1:2, the drying temperature was 180 °C, and the drying time was 2.0 hours. The volume ratio of the fifth spraying of deionized water to the dried material was 1:3, the drying temperature was 260 °C, and the drying time was 2.0 hours. The dried material was calcined at 530 °C for 5 hours to obtain catalyst J. The catalyst composition and main properties are shown in Table 1.

[0068] Comparative Example 7

[0069] Same as Example 1, the reference agent K was prepared. In the preparation process, the second drying of the formed product after washing adopted the first drying condition (conventional drying condition). The specific preparation process was as follows:

[0070] Ammonium metatungstate, ammonium molybdate, and aluminum chloride were respectively added to the dissolution tank 1 filled with deionized water to prepare a solution containing W, Mo, and Al. In the solution containing W, Mo, and Al, the weight concentration of W calculated as WO 3 was 60 g / L, the weight concentration of Mo calculated as MoO 3 was 40 g / L, and the weight concentration of Al calculated as Al 2 O 3The calculated weight concentration is 36.4 g / L. Nickel chloride is added to the dissolution tank 2 filled with deionized water to prepare a solution containing Ni. The weight concentration of Ni in the solution containing Ni, calculated as NiO, is 48 g / L. Aluminum chloride is added to the dissolution tank 3 filled with deionized water to prepare an aluminum-containing solution. The Al in the aluminum-containing solution accounts for 30% of the total Al (calculated as Al 2 O 3 in the obtained hydrofining catalyst), and it is divided into 4 equal parts by volume. Deionized water is added to the reaction tank, and the solution containing W, Mo, Al and the sodium hydroxide solution (weight concentration: 10%) are added to the reaction tank in parallel for the gelation reaction. The reaction pH value is controlled at 5.3, the reaction temperature is 60 °C. After reacting for 0.5 hours, the isomeric tridecyl alcohol random polyether TPE-1000 is added to the reaction tank. The molar ratio of the isomeric tridecyl alcohol random polyether TPE-1000 to W in the solution containing W, Mo, Al is 0.8. After stirring evenly, the solution containing Ni and the sodium hydroxide solution (weight concentration: 10%) are simultaneously dropped into the reaction slurry. The reaction temperature remains unchanged, and the reaction time is 1.0 hour. At the end of the reaction, the pH value is controlled at 8.9 to form a precipitate slurry containing nickel, molybdenum, tungsten, and aluminum. The obtained slurry is aged. The aging temperature is 76 °C. The pH value during aging is first controlled at 13.1. After aging for 0.2 hours, 1 part of the aluminum-containing solution is added, and then the aging pH value is controlled at 9.7. After aging for 0.3 hours, the pH value is then controlled at 7.7, and the aging time is 0.2 hours. The above operation process is repeated 4 times to end the aging. The aged slurry is filtered, and the filter cake is dried at 100 °C for 8 hours, rolled, and extruded into strips. It is washed with deionized water at room temperature until neutral. Then the washed wet strips are dried at 90 °C for 8 hours, and the dried material is calcined at 530 °C for 5 hours to obtain catalyst K. The catalyst composition and main properties are shown in Table 1.

[0071] Example 5

[0072] This example is an experiment for evaluating the activity of the catalyst of the present invention and is compared with the catalysts of the comparative examples. The catalysts A, B, C, D of the present invention and the catalysts E, F, G, H, I, J, K of the comparative examples are respectively used to conduct a comparative evaluation test on a 200 mL small-scale hydrogenation device. In order to further evaluate the ability of the catalyst to saturate aromatics, catalytic diesel with a high aromatic content is selected as the test raw material. The main properties of the raw material are shown in Table 3. The process conditions for evaluating the catalyst activity: the hydrogen partial pressure is 6.4 MPa, the reaction temperature is 362 °C, and the liquid hourly space velocity is 2.1 h -1, the hydrogen-oil volume ratio is 500:1, and the evaluation results are shown in Table 5. As can be seen from Tables 1-2, compared with the catalysts of the comparative examples, the catalyst of the present invention has more surface active metals and a hierarchical pore distribution. As can be seen from Table 3, the raw material oil used for the catalyst activity evaluation has a high aromatic content, which will also increase the difficulty of hydrogenation saturation, ultra-deep hydrodesulfurization and denitrification of the raw material oil. From the evaluation results in Tables 4-5, it can be seen that the catalyst of the present invention not only has excellent hydrodesulfurization activity and denitrification activity, but also has excellent hydrogenation saturation performance, effectively reducing the aromatic content of heavy distillate oil. The catalyst of the present invention is used for processing heavy distillate oil, especially for processing inferior diesel fractions with high aromatic content and great processing difficulty, and has excellent hydrogenation saturation, hydrodesulfurization and denitrification performance, effectively reducing the polycyclic aromatic hydrocarbon content and improving the cetane number of diesel.

[0073] Table 1 Composition and Properties of Catalysts Prepared in Examples and Comparative Examples

[0074]

[0075] Continued Table 1

[0076]

[0077] Table 2 Weight Content Ratio of Active Metal Oxides in the Surface and Bulk Phases of the Catalyst

[0078]

[0079] Continued Table 2

[0080]

[0081] Table 3 Main Properties of Raw Material Oil

[0082]

[0083] Table 4 Catalyst Activity Evaluation Results

[0084]

[0085] Continued Table 4

[0086]

[0087] Table 5 Contents of Different Nitrides in Hydrorefined Oil

[0088]

[0089] Continued Table 5

[0090]

Claims

1. A preparation method of a hydrofining catalyst, characterized in that it includes the following steps: (1) A solution containing W, Mo, and Al and a precipitant are added to a reaction tank in a co-current manner for gelation reaction. After the reaction, a random polyether polyoxyethylene-polyoxypropylene copolymer is added to obtain slurry I. The pH value of the gelation reaction is 5-6; (2) A solution containing Ni and a precipitant are added dropwise to slurry I obtained in step (1). After gelation reaction for a period of time, slurry II is obtained. Slurry II is continuously subjected to n times of three-stage decreasing pH aging, where n is an integer from 2 to 8; Each time, 1 / n of the solution containing Al is added at the end of the first-stage pH value aging; The specific process of each three-stage decreasing pH value aging is as follows: The aging temperature of each stage is 60-98 °C; In the first stage, the pH value is 11.0-13.5, and the aging time is 0.05-0.5 hours. After the aging ends, 1 / n of the solution containing Al is added; In the second stage, the pH value is adjusted to 8.5-10.5, and the aging time is 0.05-0.5 hours; In the third stage, the pH value is adjusted to 5.5-8.3, and the aging time is 0.05-0.5 hours; The aged slurry III is filtered to obtain a solid-phase material; (3) The solid-phase material obtained in step (2) is first dried, formed, washed, and then secondarily dried and calcined to obtain a hydrofining catalyst; The conditions of the first drying are: drying at 40-150 °C for 1-48 hours; The drying conditions of the second drying are as follows: a. First, the material is dried at 60-100 °C for 1.0-8.5 hours; b. Water is evenly sprayed on the material obtained in step a. The volume ratio of the added water to the volume of the dried material is 1:4-4:1, and then it is dried at a temperature of 150-280 °C for 0.5-4.0 hours; c. Repeat the process of step b 2-9 times; Among them, the volume ratio of the added water to the volume of the dried material in the first time is greater than 1:1, and the volume ratio of the added water to the volume of the dried material in the last time is less than 1:

1.

2. The method according to claim 1, characterized in that: In the solution containing W, Mo, and Al described in step (1), the weight concentration of W calculated as WO 3 is 5 to 120 g / L, the weight concentration of Mo calculated as MoO 3 is 5 to 110 g / L, and the weight concentration of Al calculated as Al 2 O 3 is 2 to 90 g / L; among them, when preparing the solution containing W, Mo, and Al, the tungsten source used is ammonium metatungstate, the molybdenum source is ammonium molybdate, and the aluminum source is one or more of aluminum nitrate, aluminum sulfate, aluminum chloride, and aluminum acetate.

3. The method according to claim 1, characterized in that: The conditions of the gelation reaction in step (1) are: the reaction temperature is 30-95 °C, and the reaction time is 0.1-1.0 hours.

4. The method according to claim 1, characterized in that: The random polyether polyoxyethylene-polyoxypropylene copolymer described in step (1) is selected from one or more of isomeric tridecanol random polyether TPE-1000, propylene glycol random polyether PPE-1500, glycerol random polyether GPE-3000, butanol random polyether BPE-1000, butanol random polyether BPE-1500, butanol random polyether BPE-2500, lauric acid random polyether LPE-1200, and dodecanol random polyether CPE-1500; The molar ratio of the random polyether polyoxyethylene-polyoxypropylene copolymer to W is 0.2-1.

8.

5. The method according to claim 1, characterized in that: In the Ni-containing solution described in step (2), the weight concentration of Ni calculated as NiO is 5 to 130 g / L; in the Al-containing solution, the weight concentration of Al calculated as Al 2 O 3 is 5 to 70 g / L.

6. The method according to claim 1, characterized in that: The precipitants described in steps (1) and (2) are both basic precipitants, and are selected from one or more of sodium carbonate, sodium bicarbonate, ammonia water, sodium hydroxide, potassium hydroxide, potassium carbonate or potassium bicarbonate.

7. According to the method described in claim 1, it is characterized in that: The precipitants described in steps (1) and (2) are ammonia water and sodium hydroxide solution, the concentration of ammonia water is 5wt% - 15wt%, and the concentration of sodium hydroxide solution is 7wt% - 20wt%.

8. According to the method described in claim 1, it is characterized in that: The conditions for the gel-forming reaction described in step (2) are: the reaction temperature is 30 - 95 °C, the pH value at the end is controlled at 8.0 - 12.0, and the reaction time is 0.5 - 2.5 hours.

9. According to the method described in claim 1, it is characterized in that: In step (2), the Al added through the solution containing Al accounts for 5% to 55% of the total Al in the obtained hydrofining catalyst calculated as Al 2 O 3 by weight.

10. According to the method described in claim 1, it is characterized in that: The volume ratio of the added water to the volume of the dried material decreases successively as the number of drying times in step b increases.

11. According to the method described in claim 1, it is characterized in that: The total drying time for the second drying is 5 - 40 hours.

12. According to the method described in claim 1, it is characterized in that: The calcination conditions described in step (3) are as follows: calcination is carried out at 350 - 650 °C for 1 - 24 hours.

13. A hydrofining catalyst prepared by the method described in any one of claims 1 - 12, it is characterized in that The catalyst is a bulk hydrofining catalyst, comprising a composite oxide of W, Mo, Ni and Al; the catalyst particles include an outer surface layer, an intermediate layer and a central core, and the average pore diameter decreases in a gradient, that is, the average pore diameter of the outer surface layer is greater than that of the intermediate layer, and the average pore diameter of the intermediate layer is greater than that of the central core; the average pore diameter of the outer surface layer is 10-18 nm, the average pore diameter of the intermediate layer is 7-10 nm, and the average pore diameter of the central core is 3-7 nm, wherein on the cross-section of the catalyst particle, the length from the outermost edge to the center point is R; the thickness of the outer surface layer is 0.2R-0.4R, the thickness of the intermediate layer is 0.2R-0.5R, and the rest is the central core; the molar ratio of W / Mo is 1:12-10:1, and the molar ratio of Ni / (Mo + W) is 1:12-12:1; wherein the sum of the weight contents of the surface active metal components WO 3 and NiO and the sum of the weight contents of the bulk active metal components WO 3 and NiO is in the ratio of 2.0:1-5.5:1, and the sum of the weight contents of the surface active metal components MoO 3 and NiO and the sum of the weight contents of the bulk active metal components MoO 3 and NiO is in the ratio of 1.8:1-4.5:

1.

14. According to the hydrofining catalyst described in claim 13, it is characterized in that: Based on the weight of the hydrofining catalyst, the total content of Ni, W and Mo in terms of oxides is 35% - 95%, and the alumina content is 5% - 65%.

15. According to the hydrofining catalyst described in claim 13, it is characterized in that: The specific surface area of the catalyst particles is 200 - 500 m 2 / g, and the pore volume is 0.25 - 1.0 mL / g.

16. According to the hydrofining catalyst described in claim 13, it is characterized in that: The particle size of the catalyst particles is 1 - 10 mm.

17. Application of a hydrofining catalyst prepared by the method described in any one of claims 1 - 12 in the ultra-deep hydrodesulfurization, denitrification reaction and hydrodearomatization of heavy diesel fractions, wherein the aromatic content in the heavy diesel fraction is 50wt% - 85wt% and the cetane number is less than 24.

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