Hydrofining catalyst and method for making same

Abstract

The application discloses a kind of hydrofining catalyst and preparation method thereof.Hydrofining catalyst includes hydrogenation active metal component W, Mo and Ni, amorphous alumina, copper oxide and graphene;Wherein the weight ratio of surface phase and bulk phase active WO3 is 2.5:1~6.5:1, the weight ratio of surface phase and bulk phase MoO3 is 2.7:1~6.6:1;The weight ratio of surface phase and bulk phase CuO and NiO is 2.8:1~7.3:1;The weight ratio of surface phase and bulk phase graphene is 1.8:1~4.5:1.Preparation method is as follows: (1) the solution containing W, Mo, Al and first precipitant are carried out and current gelation reaction, obtain first slurry;(2) the solution containing Ni and second precipitant are current dropwise added to first slurry, gelation reaction obtains second slurry;(3) second slurry is carried out n times aging treatment under the condition that temperature is 60~98 ℃, filter, filter cake is dried, shaping, and is prepared into hydrofining catalyst.The catalyst component distribution of the application is reasonable, active metal utilization rate is high, with higher hydrogenation performance, suitable for application in heavy distillate oil hydrogenation reaction.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of catalyst preparation, and particularly relates to a hydrofining catalyst and a preparation method thereof. BACKGROUND

[0002] In the distillate hydrogenation reaction process, the bulk catalyst is the highest active hydrogenation catalyst at present, and the active metal content reaches more than 70%. Although the bulk hydrogenation catalyst has high active metal content, the catalyst surface is small, the active metal is unevenly dispersed, and the different hydrogenation active metals are randomly distributed, so that the active metals cannot have good coordination, the high content of the metal is prone to excessive accumulation of metal particles, the active phase is reduced, the active metal cannot become a hydrogenation active center, the utilization rate of the active metal of the catalyst is affected, and the use cost of the catalyst is also increased.

[0003] CN1951561A discloses a method for preparing a hydrogenation catalyst by co-precipitation. The catalyst is prepared by co-precipitation of active metals Ni, W components and a precipitator in parallel flow to generate Ni x W y O z The composite oxide precursor can be added with an aluminum salt solution or directly added with aluminum hydroxide after gelation, and then mixed with MoO3 by beating, filtered, shaped, and activated to obtain the final catalyst. In the preparation of the bulk catalyst by the method, the active metals are excessively accumulated, and the utilization rate of the active metals is reduced.

[0004] CN101255356A discloses a preparation method of a non-supported catalyst. The method is to mix the active metal precursors of Group VIII and Group ⅥB with urea and react in the urea melting state, remove the excess urea, and obtain catalyst particles, which can be shaped by adding a binder. In the method, urea is added as a precipitator, and after the reaction, the excess urea needs to be removed by heating, and then the binder is added for shaping. Thus, the catalyst prepared by the method has uneven pore size distribution and poor crushing strength.

[0005] CN106179380A discloses a bulk hydrofining catalyst and a preparation method thereof. The method is to prepare a nickel-aluminum mixed precipitate by the normal addition method, prepare a tungsten-molybdenum-aluminum mixed precipitate by the parallel flow precipitation method, mix the two, and then age, filter, and obtain a metal mixture. The metal mixture is treated by water vapor under suitable conditions and added with urea, the material after hydrothermal treatment is dried, shaped, and calcined to obtain the catalyst. The bulk catalyst prepared by the method has high surface active metal content, but the catalyst has uneven pore distribution, the catalyst surface has small pore size, and the surface active metal is excessively accumulated, which does not improve the utilization rate of the surface active metal.

[0006] CN106513006A discloses a preparation method of a bulk phase hydrofining catalyst, which comprises: mixing a Ni-containing compound with deionized water under ultrasonic environment for pre-dispersion, then adding a Mo-containing compound to form a Ni-Mo fine grain structure, then adding a W-containing compound and a complexing agent for hydrothermal reaction, and then mixing and kneading the obtained active component powder with aluminum hydroxide dry gel, extruding into strips, drying and calcining to obtain the catalyst. The catalyst prepared by the method has uniform dispersion between different active phase grains, high active metal utilization rate, excellent pore structure properties, and improved removal efficiency of complex sulfur compounds in poor diesel oil. However, the active metal in the bulk phase catalyst is not fully utilized, the amount of surface active metal is not large, the hydrodenitrogenation activity is not improved, and the removal efficiency of complex sulfur compounds with high nitrogen content is limited.

[0007] CN109692686A discloses a hydrofining catalyst and a preparation method thereof. The hydrofining catalyst is a bulk phase hydrofining catalyst. A mixed solution A containing Ni, W and Al components is reacted with a precipitant in a concurrent flow, and the obtained slurry is aged. A mixed solution B containing W and Al components, a precipitant and a MoO3 slurry are added to the aged slurry in a concurrent flow, and then aged. The hydrofining catalyst is prepared through steps such as drying and molding. After sulfidation of the catalyst, the average stacking number of MoS2 / WS2 is large, the specific surface area and pore volume of the catalyst are small, and the average sheet length of MoS2 / WS2 is short. The catalyst has high hydrodesulfurization and hydrodenitrogenation reaction activity, but the aromatic saturation performance for treating heavy oil is not significantly improved.

[0008] CN114471595A discloses a preparation method of a hydrofining catalyst, which comprises the following steps: (1) preparing a slurry containing nickel, tungsten, molybdenum and aluminum precipitates; (2) aging the obtained slurry, and after aging, performing solid-liquid separation, drying and molding the solid material to obtain a molded product; and (3) desalting, drying and calcining the molded product to obtain the hydrofining catalyst. The catalyst has increased pore volume and pore size by effective desalting, but the generated oxide particles are not uniform, which affects the utilization of active metals in the catalyst.

[0009] In the existing co-precipitation method for preparing bulk phase catalysts, different precipitation methods and gelation conditions have a great influence on the physical and chemical properties of the prepared catalysts, which further affects the physical and chemical properties of the bulk phase catalysts and the utilization rate of active metals. Therefore, how to further improve the utilization rate of active metals in bulk phase catalysts and fully utilize the active metals in the catalysts is a problem to be solved at present.

[0010] The active metal content in the bulk catalyst is high, which enhances the selective adsorption of hydrogen by the catalyst, thereby improving the utilization of active metals in the bulk catalyst, further improving the active centers of the catalyst, and reducing the use cost of the bulk catalyst. Graphene is a crystal with a two-dimensional spatial structure formed by sp 2 Hybridization of carbon atoms, which has a strong hydrogen molecule adsorption capacity and promotes metal dispersion, can effectively improve the utilization rate of active metals in the bulk catalyst.

[0011] CN111068750A discloses a modified alumina carrier, a preparation method thereof and a hydrofining catalyst. A pseudo-boehmite precursor slurry, a mesoporous molecular sieve, graphene and an organic alcohol are mixed, aged, shaped, dried and calcined to obtain a modified alumina carrier. CN108067221A discloses a preparation method of a superfine modified fly ash-oxidized graphene-palladium hydrogenation catalyst. A small amount of oxidized graphene is added during the preparation process. The above preparation method adds graphene to the carrier, but graphene is not fully utilized. CN106944065A provides a preparation method of a graphene supported nickel hydrogenation catalyst. Nickel is supported on graphene by the ammonia evaporation method. However, the carrier of the catalyst is oxidized graphene, which greatly increases the cost of the catalyst and limits its application.

[0012] Currently, to solve the problem of low utilization rate of graphene in hydrogenation catalysts, how to improve the interaction between graphene and hydrogenation active metals, fully utilize graphene and improve the utilization rate of active metals in bulk catalysts is also a problem to be solved. SUMMARY

[0013] To overcome the shortcomings of the prior art, the present application provides a hydrofining catalyst and a preparation method thereof. The catalyst of the present application has a reasonable distribution of components, a high utilization rate of active metals, high hydrogenation performance, and is particularly suitable for use in heavy distillate oil hydrogenation reactions.

[0014] The hydrofining catalyst of the present application is a bulk catalyst, comprising hydrogenation active metal components W, Mo and Ni, amorphous alumina, copper oxide and graphene; the total content of the hydrogenation active metal components W, Mo and Ni in terms of oxides is 37% to 82%, preferably 40% to 77%, the content of the amorphous alumina is 8% to 38%, preferably 10% to 36%, the content of the copper oxide is 5% to 17%, preferably 5% to 15%, and the content of the graphene is 3% to 16%, preferably 3% to 14%, based on the weight of the catalyst; the weight ratio of the content of the surface phase active metal component WO3 to the content of the bulk phase active metal component WO3 is 2.5:1 to 6.5:1, preferably 2.8:1 to 6.2:1, the weight ratio of the content of the surface phase active metal component MoO3 to the content of the bulk phase active metal component MoO3 is 2.7:1 to 6.6:1, preferably 2.9:1 to 6.3:1, the ratio of the sum of the weight contents of the surface phase active metal components CuO and NiO to the sum of the weight contents of the bulk phase active metal components CuO and NiO is 2.8:1 to 7.3:1, preferably 3.0:1 to 6.7:1, and the weight ratio of the content of the graphene in the surface phase to the content of the graphene in the bulk phase is 1.8:1 to 4.5:1, preferably 2.1:1 to 4.0:1. In the hydrofining catalyst of the present application, the molar ratio of W / Mo is 1:12 to 10:1, preferably 1:10 to 8:1, and the molar ratio of Ni / (Mo+W) is 1:12 to 12:1, preferably 1:10 to 10:1.

[0015] The pore size distribution of the hydrofining catalyst of the present application is as follows: the pore volume of the pores with a diameter of 6 nm or less accounts for 2% to 13% of the total pore volume, the pore volume of the pores with a diameter of 6 to 10 nm accounts for 45% to 65% of the total pore volume, the pore volume of the pores with a diameter of 10 to 15 nm accounts for 18% to 40% of the total pore volume, and the pore volume of the pores with a diameter of 15 nm or more accounts for 5% to 22% of the total pore volume; the specific surface area of the catalyst is 200 to 500 m 2 / g, and the pore volume is 0.25 to 1.0 mL / g.

[0016] The preparation method of the hydrofining catalyst of the present application comprises the following steps:

[0017] (1) a solution containing W, Mo and Al is subjected to a parallel flow gelation reaction with a first precipitating agent to obtain a first slurry;

[0018] (2) a solution containing Ni is subjected to a parallel flow dropwise addition to the first slurry with a second precipitating agent to obtain a second slurry;

[0019] (3) the second slurry is subjected to n times of aging treatment at a temperature of 60-98 DEG C, and each aging treatment process comprises the following steps: firstly, aging for 0.05-0.5 hours at a pH value of 11.0-13.5, then adding 1 / n Al and Cu-containing solution and 1 / n graphene, adjusting the pH value to 8.5-10.5, continuing to age for 0.05-0.5 hours, adjusting the pH value to 4.5-6.3, aging for 0.05-0.5 hours, and finally adjusting the pH value to 11.0-13.5 for the next aging, until the aging treatment is completed, to obtain a third slurry; wherein n is an integer of 2-8;

[0020] (4) the third slurry is filtered, the filter cake is dried and shaped, and the shaped material is washed, dried and calcined to obtain a hydrofining catalyst.

[0021] In the method, the W, Mo and Al-containing solution in step (1) has a WO3 weight concentration of 5-120 g / L, preferably 10-110 g / L, a MoO3 weight concentration of 5-110 g / L, preferably 10-100 g / L, and an Al2O3 weight concentration of 2-90 g / L, preferably 6-85 g / L; wherein, when the W, Mo and Al-containing solution is prepared, the commonly used tungsten source 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.

[0022] In the method, the gelation reaction condition in step (1) is that the reaction temperature is 30-95 DEG C, preferably 40-95 DEG C, the concurrent flow reaction pH value is controlled at 5-6, and the reaction time is 0.1-1.0 hours.

[0023] In the method, the Ni-containing solution in step (2) has a NiO weight concentration of 5-130 g / L, preferably 10-115 g / L; and when the Ni-containing solution is prepared, the commonly used nickel source is one or more of nickel sulfate, nickel nitrate and nickel chloride.

[0024] In the method, the first and second precipitants are both alkaline precipitants, and are selected from one or more of sodium hydroxide, potassium hydroxide, potassium carbonate and potassium bicarbonate solution, preferably sodium hydroxide solution, and the precipitant concentration is 7wt%-20wt%.

[0025] In the method, the gelation reaction condition in step (2) is that the reaction temperature is 30-95 DEG C, preferably 40-95 DEG C, the pH value at the end of the reaction is 8.0-10.5, and the reaction time is 0.5-2.5 hours.

[0026] In the method, the weight concentration of Al in the Al and Cu-containing solution in step (3) is 5-70 g / L, preferably 8-60 g / L, and the weight concentration of Cu in the Al and Cu-containing solution in step (3) is 7-80 g / L, preferably 9-80 g / L; when the Al and Cu-containing solution is prepared, the aluminum source is generally one or more of soluble aluminum salts such as aluminum nitrate, aluminum sulfate, aluminum chloride, etc., and the copper source is generally one or more of copper-containing nitrate and / or acetate.

[0027] In the method, the Al and Cu-containing solution in step (3) is divided into 2-8 parts by volume according to the number of aging treatments.

[0028] In the method, the graphene in step (3) can be one or two of single-layer graphene, double-layer graphene, few-layer graphene or multi-layer graphene. The preparation method of the graphene is known to those skilled in the art. The graphene oxide is ultrasonically exfoliated in water for 0.4-3.5 h to prepare a graphene oxide suspension, and then hydrazine hydrate and / or sodium borohydride are added to reduce the graphene oxide to graphene. The graphene is divided into 2-8 parts by mass according to the number of aging treatments.

[0029] In the method, the acid and base used for adjusting the pH value during the aging treatment can be inorganic salts, inorganic acids and inorganic bases containing no aluminum element, the inorganic acid can be hydrochloric acid and acetic acid, the inorganic base can be one or more of sodium carbonate, sodium bicarbonate and sodium hydroxide, and the concentration and amount of the acid and base solution can be adjusted according to the actual preparation needs.

[0030] In the method, in step (3), the Al added by the Al and Cu-containing solution accounts for 5%-55% of the Al (calculated as Al2O3) in the obtained hydrofining catalyst, preferably 6%-50%.

[0031] In the method of the present application, the drying, shaping and washing in step (4) can be carried out by using conventional methods in the art. The drying conditions are as follows: drying at 40-150 DEG C for 1-48 hours, preferably at 50-120 DEG C for 4-36 hours. During the shaping process, conventional shaping aids such as one or more of a peptizing agent, an extrusion aid, etc. can be added as needed. The peptizing agent is one or more of hydrochloric acid, nitric acid, sulfuric acid, acetic acid, oxalic acid, etc., and the extrusion aid refers to a substance that is beneficial to extrusion shaping, such as one or more of sesbania gum, carbon black, graphite powder, citric acid, etc., and the amount of the extrusion aid is 1-10 wt% of the total material dry basis. The washing is generally carried out by using deionized water or a solution containing decomposable salts (such as ammonium acetate, ammonium chloride, ammonium nitrate, etc.) and washing to neutral. In the method for preparing the hydrofining catalyst of the present application, the shape of the catalyst can be sheet, spherical, cylindrical strip or irregular strip (three-leaf clover, four-leaf clover) as needed, and preferably cylindrical strip or irregular strip (three-leaf clover, four-leaf clover). The diameter of the catalyst can be 0.8-2.0 mm fine strip or >2.5 mm thick strip.

[0032] In the method of the present application, the calcination conditions in step (4) are as follows: calcination at 350-650 DEG C for 1-24 hours, preferably at 400-600 DEG C for 2-12 hours.

[0033] The hydrofining catalyst of the present application is used in the ultra-deep hydrodesulfurization, hydrodenitrogenation reaction and hydrodearomatization of heavy diesel oil fractions, wherein the aromatic content in the heavy diesel oil fraction is 50-85 wt%, and the cetane number is less than 24.

[0034] Compared with the prior art, the present application has the following advantages:

[0035] The catalyst surface phase of the present application contains more Ni and Cu and graphene, and the graphene has a strong hydrogen molecule adsorption capacity, which matches the hydrogen overflow property of Ni-Cu, and the combination of the two can effectively activate hydrogen molecules into active hydrogen, thereby improving the utilization rate of graphene in the hydrogenation catalyst and further improving the utilization rate of active metals in the bulk phase catalyst.

[0036] 2. In the method of the present application, the W, Mo and Al-containing solution is first precipitated, and a Ni-containing solution is added dropwise in the obtained slurry at a specific pH value, so that the hydrogenation active metals tungsten, nickel and molybdenum are more uniformly dispersed in the catalyst, which is beneficial to improving the hydrogenation saturation activity of the W-Ni combination and the hydrodenitrogenation activity of the Mo-Ni combination, and at the same time, more nickel is dispersed in the surface phase of the catalyst, and the hydrodesulfurization and hydrodenitrogenation properties of the catalyst are significantly improved.

[0037] 3、The method of the present application adds Al and Cu-containing solution and graphene in batches in the aging process, and makes amorphous oxide in the oxide particles dissolve through multiple pH value swings, modifies the size of the oxide particles, makes the oxide particles more uniform, exposes more Cu and Ni in the surface phase, is conducive to the function of graphene, and can also increase the macropores in the bulk phase catalyst, so that the macromolecular reactants can easily pass through the pores.

[0038] 4、The present application controls the preparation steps and conditions comprehensively, so that the graphene in the bulk phase catalyst fully plays its role, improves the utilization rate of active metals, reduces the preparation cost of the bulk phase catalyst, improves the hydrogenation activity of the catalyst, is especially beneficial to the aromatic saturation of heavy oil, effectively reduces the content of polycyclic aromatic hydrocarbons, and improves the cetane number. The hydrofining catalyst of the present application is particularly suitable for application in diesel fraction ultra-deep hydrodesulfurization, denitrification and dealkylation reactions. DETAILED DESCRIPTION

[0039] In the present application, the specific surface area and pore volume are determined by low-temperature liquid nitrogen adsorption method, and the mechanical strength is determined by side pressure method.

[0040] In the present application, the surface active metal content of the catalyst is determined by X-ray photoelectron spectroscopy (XPS), and the bulk active metal content of the catalyst is determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES).

[0041] Take 200g of graphene oxide, add it to 1.2L of deionized water, stir until uniform, ultrasonic for 1h, prepare graphene oxide suspension, then add 500g of sodium borohydride, reduce graphene oxide to graphene, filter, wash, dry to obtain graphene. Example 1

[0042] Ammonium metatungstate, ammonium molybdate and aluminum chloride were added into dissolving tank 1 containing deionized water to prepare a W, Mo and Al containing solution, in which the weight concentration of W as WO3 was 52 g / L, the weight concentration of Mo as MoO3 was 32 g / L, and the weight concentration of Al as Al2O3 was 32.2 g / L. Nickel chloride was added into dissolving tank 2 containing deionized water to prepare a Ni containing solution, in which the weight concentration of Ni as NiO was 44 g / L. Aluminum chloride and copper nitrate were added into dissolving tank 3 containing deionized water to prepare an Al and Cu containing solution, in which the Al accounted for 30% of the total Al (as Al2O3) in the obtained hydrofining catalyst, and the weight concentration of Cu as CuO was 12 g / L. The Al and Cu containing solution was divided into 5 equal parts by volume, and 14 grams of graphene was also divided into 5 equal parts. Deionized water was added into a reaction tank, and the W, Mo and Al containing solution and sodium hydroxide solution (10% by weight) were added into the reaction tank to perform a gelation reaction. The reaction pH value was controlled at 5.3, and the reaction temperature was 60°C. After 0.7 hours of reaction, the Ni containing solution and sodium hydroxide solution (10% by weight) were added into the reaction slurry to perform a reaction. The reaction temperature was not changed, and the reaction time was 1.0 hour. The pH value was controlled at 9.2 at the end of the reaction, and a precipitate slurry containing nickel, molybdenum, tungsten and aluminum was obtained. The obtained slurry was aged. The aging temperature was 76°C. The pH value was controlled at 13.1 at the beginning of the aging, and the aging time was 0.2 hours. Then, one part of the Al and Cu containing solution and graphene was added, and the pH value was controlled at 9.7 after aging. The aging time was 0.2 hours. Then, the pH value was controlled at 5.7, and the aging time was 0.2 hours. The above operation was repeated 5 times, and the aging was ended. The filter cake was dried at 100°C for 8 hours, was rolled, and was extruded into a strip. The strip was washed with deionized water at room temperature until neutral. The wet strip was dried at 100°C for 8 hours after washing. The dried material was calcined at 530°C for 5 hours to obtain catalyst A. The catalyst composition and main properties are shown in Table 1. Example 2

[0043] Ammonium metatungstate, ammonium molybdate and aluminum chloride were added into dissolving tank 1 containing deionized water to prepare a W, Mo and Al containing solution, in which the weight concentration of W as WO3 was 40 g / L, the weight concentration of Mo as MoO3 was 40 g / L, and the weight concentration of Al as Al2O3 was 31.2 g / L. Nickel chloride was added into dissolving tank 2 containing deionized water to prepare a Ni containing solution, in which the weight concentration of Ni as NiO was 46 g / L. Aluminum chloride and copper nitrate were added into dissolving tank 3 containing deionized water to prepare an Al and Cu containing solution, in which the Al accounted for 35% of the total Al (as Al2O3) in the obtained hydrofining catalyst, and the weight concentration of Cu as CuO was 14 g / L. The Al and Cu containing solution was divided into 6 equal parts by volume, and the graphene was also divided into 6 equal parts. Deionized water was added into a reaction tank, and the W, Mo and Al containing solution and sodium hydroxide solution (weight concentration of 12%) were added into the reaction tank to perform a gelation reaction. The reaction pH value was controlled at 5.5, and the reaction temperature was 65°C. After 0.6 hours of reaction, the Ni containing solution and sodium hydroxide solution (weight concentration of 12%) were added into the reaction slurry to perform a reaction. The reaction temperature was not changed, and the reaction time was 1.2 hours. The pH value was controlled at 9.5 at the end of the reaction. A precipitate slurry containing nickel, molybdenum, tungsten and aluminum was obtained. The obtained slurry was aged. The aging temperature was 80°C. The pH value was controlled at 13.3 at the beginning of the aging, and the aging time was 0.15 hours. Then, one part of the Al and Cu containing solution and graphene were added. The aging pH value was controlled at 9.5, and the aging time was 0.1 hours. Then, the pH value was controlled at 5.1, and the aging time was 0.15 hours. The above operation was repeated 6 times, and the aging was ended. The filter cake was dried at 90°C for 8 hours, was rolled, and was extruded into a strip. The strip was washed with deionized water at room temperature until neutral. The wet strip was dried at 100°C for 10 hours after washing. The dried material was calcined at 510°C for 5 hours to obtain catalyst B. The catalyst composition and main properties are shown in Table 1. Example 3

[0044] Ammonium metatungstate, ammonium molybdate and aluminum chloride were added into dissolving tank 1 containing deionized water to prepare a W, Mo, Al-containing solution, in which the weight concentration of W as WO3 was 34 g / L, the weight concentration of Mo as MoO3 was 30 g / L, and the weight concentration of Al as Al2O3 was 33 g / L. Nickel chloride was added into dissolving tank 2 containing deionized water to prepare a Ni-containing solution, in which the weight concentration of Ni as NiO was 60 g / L. Aluminum chloride and copper nitrate were added into dissolving tank 3 containing deionized water to prepare an Al and Cu-containing solution, in which the Al accounted for 25% of the total Al (as Al2O3) in the obtained hydrofining catalyst, the weight concentration of Cu as CuO was 14 g / L, and the Al and Cu-containing solution was divided into 5 equal parts. Eighteen grams of graphene was divided into 5 equal parts. Deionized water was added into a reaction tank, and the W, Mo, Al-containing solution and sodium hydroxide solution (10% by weight) were added into the reaction tank to perform a gelation reaction, the pH value was controlled at 5.5, the reaction temperature was 55°C, and the reaction time was 0.8 hours. Then, the Ni-containing solution and sodium hydroxide solution (10% by weight) were added into the reaction slurry, the reaction temperature was not changed, and the reaction time was 1.1 hours. The pH value was controlled at 9.7 at the end of the reaction, and a precipitate slurry containing nickel, molybdenum, tungsten and aluminum was obtained. The obtained slurry was aged, the aging temperature was 83°C, the pH value was controlled at 12.6 at the beginning of the aging, and the aging time was 0.2 hours. Then, one part of the Al and Cu-containing solution and graphene were added, the pH value was controlled at 9.3, and the aging time was 0.15 hours. Then, the pH value was controlled at 5.2, and the aging time was 0.15 hours. The above operation was repeated 5 times, and the aging was ended. The filter cake was dried at 80°C for 12 hours, was rolled, and was extruded into a strip. The wet strip was washed with deionized water at room temperature until neutral. Then, the washed wet strip was dried at 95°C for 7.0 hours, and the dried material was calcined at 550°C for 4 hours to obtain catalyst C. The catalyst composition and main properties are shown in Table 1. Example 4

[0045] Ammonium metatungstate, ammonium molybdate and aluminum chloride were added into dissolving tank 1 containing deionized water to prepare a W, Mo and Al-containing solution, in which the weight concentration of W as WO3 was 44 g / L, the weight concentration of Mo as MoO3 was 36 g / L, and the weight concentration of Al as Al2O3 was 30.8 g / L. Nickel chloride was added into dissolving tank 2 containing deionized water to prepare a Ni-containing solution, in which the weight concentration of Ni as NiO was 44 g / L. Aluminum chloride and copper nitrate were added into dissolving tank 3 containing deionized water to prepare an Al and Cu-containing solution, in which the Al accounted for 30% of the total Al (as Al2O3) in the obtained hydrofining catalyst, the weight concentration of Cu as CuO was 16 g / L, and the Al and Cu-containing solution was divided into 4 equal parts. 16 grams of graphene was divided into 4 equal parts. Deionized water was added into a reaction tank, and the W, Mo and Al-containing solution and a sodium hydroxide solution (10% by weight) were added into the reaction tank to perform a gelation reaction, the pH value was controlled at 5.6, the reaction temperature was 68°C, and the reaction time was 0.5 hours. Then, the Ni-containing solution and a sodium hydroxide solution (10% by weight) were added into the reaction slurry, the reaction temperature was not changed, and the reaction time was 1.5 hours. The pH value was controlled at 9.2 at the end of the reaction, and a precipitate slurry containing nickel, molybdenum, tungsten and aluminum was generated. The obtained slurry was aged, the aging temperature was 83°C, the pH value was controlled at 12.8 at the beginning of the aging, 1 part of the Al and Cu-containing solution and graphene was added after the aging time of 0.2 hours, the pH value was controlled at 9.7, the aging time was 0.2 hours, the pH value was controlled at 5.3 after the aging time of 0.2 hours, the aging time was 0.2 hours, and the above operation was repeated 4 times to end the aging. The filter cake was dried at 110°C for 9 hours, was rolled and was extruded into a strip. The wet strip was washed with deionized water at room temperature until neutral. Then, the washed wet strip was dried at 103°C for 7.0 hours, and the dried material was calcined at 530°C for 5 hours to obtain catalyst D. The catalyst composition and main properties are shown in Table 1. Comparative Example 1

[0046] According to the preparation method disclosed in CN106179380A, a reference agent E was prepared, and the active metal oxide content was 74%, and the specific process was as follows:

[0047] A mixed solution A was prepared by dissolving a nickel chloride solution and an aluminum chloride solution in deionized water, the weight concentration of NiO in the mixed solution A being 48 g / L and the weight concentration of AI2O3 being 26 g / L. A mixed solution B was prepared by dissolving an ammonium metatungstate solution, an ammonium molybdate solution and an aluminum chloride solution in deionized water, the weight concentration of WO3 in the mixed solution B being 60 g / L, the weight concentration of MoO3 being 40 g / L and the weight concentration of AI2O3 being 26 g / L. A 10% (by weight) sodium hydroxide solution was added to solution A under stirring, the temperature of the gelation being maintained at 60°C, the pH value at the end of the gelation being controlled at 7.8 and the gelation time being controlled at 60 minutes, thereby forming a slurry I containing a nickel-aluminum precipitate. Deionized water was added to a reaction tank, and a 10% (by weight) sodium hydroxide solution and solution B were added to the reaction tank in a concurrent manner, the temperature of the gelation being maintained at 60°C, the pH value during the concurrent gelation being controlled at 7.8 and the gelation time being controlled at 60 minutes, thereby forming a slurry II containing a tungsten-molybdenum-aluminum precipitate. The two slurry containing precipitates were mixed and aged, the aging time being 2.8 hours, the aging temperature being 80°C and the pH value being controlled at 8.5, and then filtered, the filter cake being subjected to hydrothermal treatment in a water vapor containing urea, the molar ratio of urea to the total amount of active metal atoms being 7:1, the temperature being 250°C, the pressure being 4.0 MPa and the treatment time being 3 hours, the filter cake being dried at 100°C for 8 hours, being rolled, and being formed into a strip. The strip was washed with deionized water at room temperature until neutral, and then dried at 100°C for 10 hours and calcined at 530°C for 5 hours, thereby obtaining a catalyst E. The catalyst composition, pore distribution and main properties are shown in Table 1. Comparative Example 2

[0048] The same as in Example 1, a reference agent F was prepared, which did not contain graphene and copper oxide, the active metal oxide content being 74%. The catalyst composition, pore distribution and main properties are shown in Table 1. Comparative Example 3

[0049] The same as in Example 1, a reference agent G was prepared, the aging process of the slurry containing a nickel-molybdenum-tungsten-aluminum precipitate being performed by adding all the Al- and Cu-containing solutions and graphene at one time, the aging pH value being a fixed value, and the specific preparation process being as follows:

[0050] Ammonium metatungstate, ammonium molybdate and aluminum chloride were added into dissolving tank 1 containing deionized water to prepare a W, Mo and Al-containing solution, in which the weight concentration of W (as WO3) was 52 g / L, the weight concentration of Mo (as MoO3) was 32 g / L, and the weight concentration of Al (as Al2O3) was 32.2 g / L. Nickel chloride was added into dissolving tank 2 containing deionized water to prepare a Ni-containing solution, in which the weight concentration of Ni (as NiO) was 44 g / L. Aluminum chloride and copper nitrate were added into dissolving tank 3 containing deionized water to prepare an Al and Cu-containing solution, in which the Al accounted for 30% of the total Al (as Al2O3) in the obtained hydrofining catalyst, and the weight concentration of Cu (as CuO) was 12 g / L. Deionized water was added into a reaction tank, and the W, Mo and Al-containing solution and a sodium hydroxide solution (10% by weight) were added into the reaction tank to perform a gelation reaction, the pH value was controlled at 5.3, the reaction temperature was 60°C, and the reaction time was 0.7 hours. Then, the Ni-containing solution and the sodium hydroxide solution (10% by weight) were added into the reaction slurry to perform a reaction, the reaction temperature was not changed, the reaction time was 1.0 hour, and the pH value was controlled at 9.2 at the end of the reaction, thereby obtaining a precipitate slurry containing nickel, molybdenum, tungsten and aluminum. The obtained slurry was aged, the Al and Cu-containing solution and graphene were added into the slurry at the beginning of the aging, the aging temperature was 76°C, the pH value was 7.6 during the aging, the aging time was 2.5 hours, and the aging was ended. The filter cake was dried at 100°C for 8 hours, was rolled and was extruded into a strip. The strip was washed with deionized water at room temperature until neutral. The wet strip was dried at 100°C for 8 hours, and the dried material was calcined at 530°C for 5 hours, thereby obtaining catalyst G. The catalyst composition and main properties are shown in Table 1. Example 5

[0051] This example is an activity evaluation experiment of the catalysts of the present application, and comparative catalysts are used for comparison. The catalysts A, B, C and D of the present application and the comparative catalysts E, F and G were used for comparative evaluation experiments in a 200 mL small hydrogenation device. In order to further evaluate the aromatic saturation capacity of the catalysts, a catalytic diesel oil with high aromatic content was selected as the test raw material, and the main properties of the raw material are shown in Table 3. The catalyst activity evaluation process conditions were as follows: hydrogen partial pressure was 6.4 MPa, reaction temperature was 360°C, liquid hourly space velocity was 2.3 h -1, hydrogen oil volume ratio is 500:1, from the evaluation results of table 4~5, the catalyst of the application not only has excellent hydrodesulfurization activity and hydrodenitrogenation activity, but also has excellent hydrogenation saturation performance, effectively reduces the aromatic content of heavy distillate oil. Compared with the bulk catalyst prepared by the same method without graphene (reference catalyst F), the active metal oxide content of the catalyst of the application is 6~12m% lower than that of the bulk catalyst without graphene (reference catalyst F) when the hydrogenation activity is equivalent. The catalyst of the application is used for processing heavy distillate oil, especially for processing poor diesel oil fraction with high aromatic content and difficult to process, which has excellent hydrogenation saturation, hydrodesulfurization and hydrodenitrogenation performance, effectively reduces the content of polycyclic aromatic hydrocarbon, and improves the cetane number of diesel oil.

[0052] Table 1 Catalyst composition and properties prepared by examples and comparative examples

[0053] Catalyst No. A B C D NiO, wt% 22 23 30 22 WO3, wt% 26 20 17 22 MoO3, wt% 16 20 15 18 CuO, wt% 6 7 7 8 Al203, wt% 23 24 22 22 Graphene, wt% 7 6 9 8 Specific surface area, m 2 / g]] 285 295 278 301 Pore volume, mL / g 0.421 0.435 0.412 0.446 Pore distribution < 6 nm 6.35 5.78 8.13 5.01 6 nm ~ 10 nm 53.65 52.67 52.94 53.03 10 nm ~ 15 nm 26.67 27.25 25.61 27.42 > 15 nm 13.33 14.30 13.32 14.54

[0054] Table 1 (continued)

[0055] Catalyst No. E F G NiO, wt% 24 24 22 WO3, wt% 30 30 26 MoO3, wt% 20 20 16 CuO, wt% 6 Al203, wt% 26 26 23 Graphene, wt% - - 7 Specific surface area, m 2 / g]] 230 274 220 Pore volume, mL / g 0.342 0.401 0.315 Pore distribution < 6 nm 51.48 6.23 54.42 6 nm ~ 10 nm 31.34 53.98 29.58 10 nm ~ 15 nm 14.05 26.59 13.46 > 15 nm 3.13 13.20 2.54

[0056] Table 2 Weight content ratio of active metal oxides in catalyst surface phase and bulk phase

[0057] Catalyst No. A B C D Table phase I W Bulk phase I W ]]> 5.23 5.45 5.11 5.56 Table phase I Mo Bulk phase I Mo ]]> 5.01 5.21 4.95 5.33 Table phase I Cu+Ni Bulk phase I Cu+Ni ]]> 5.76 5.87 5.64 5.94 Table phase I 石墨烯 Bulk phase I 石墨烯 ]]> 2.89 2.97 2.80 3.05

[0058] Table 2 (continued)

[0059] Catalyst No. E F G Table phase I W Bulk phase I W ]]> 4.48 5.02 4.16 Table phase I Mo Bulk phase I Mo ]]> 4.35 4.88 4.04 Table phase I Cu+Ni Bulk phase I Cu+Ni ]]> - - 1.43 Table phase I 石墨烯 Bulk phase I 石墨烯 ]]> - - 2.18

[0060] Table 3 Main properties of raw oil

[0061] Item Analysis result Density (20°C), g / cm 3 ]] 0.9291 Distillation range, °C 162-380 S, pg / g 14650 N, pg / g 842 Aromatics, wt% 70.6 Polycyclic aromatics, wt% 45.3 Cetane number ＜24

[0062] Table 4 Catalyst activity evaluation results

[0063] Catalyst No. A B C D E F G Density of the produced oil (20°C), g / cm 3 ]] 0.8681 0.8681 0.8683 0.8680 0.8832 0.8682 0.8695 Distillation range, °C 163-366 162-366 165-367 162-365 180-377 163-366 164-370 S, pg / g 7.8 7.6 8.2 7.2 264.3 8.0 53.6 N, pg / g 4.1 3.8 4.3 3.6 80.1 4.3 19.7 Aromatics, wt% 34.1 33.9 34.3 33.2 49.1 34.0 40.1 Polycyclic aromatics, wt% 4.1 4.0 4.3 3.8 17.1 4.2 9.4 Cetane number 39.6 39.8 39.4 40.0 26.0 39.5 33.2

[0064] Table 5 Content of different nitrogen compounds in hydrogenated oil

[0065] Catalyst No. A B C D E F G Nitrogen content in hydrofinished oil, pg / g 4.1 3.8 4.3 3.6 80.1 4.3 19.7 1-MCB, pg / g 2.0 2.0 2.1 1.9 36.2 2.1 9.8 1,8-BMCB, pg / g 1.3 1.1 1.3 1.1 25.4 1.4 6.1 1,4,8-TMCB, pg / g 0.8 0.7 0.9 0.6 18.5 0.8 3.8

Claims

1. A hydrofinishing catalyst characterized by: The catalyst is a bulk catalyst, comprising hydrogenation active metal components W, Mo and Ni, amorphous aluminum oxide, copper oxide and graphene; the total content of the hydrogenation active metal components W, Mo and Ni in the form of oxides is 37% to 82% based on the weight of the catalyst, the content of the amorphous aluminum oxide is 8% to 38%, the content of the copper oxide is 5% to 17%, and the content of the graphene is 3% to 16%; the weight ratio of the surface phase active metal component WO3 to the bulk phase active metal component WO3 is 2.5:1 to 6.5:1, the weight ratio of the surface phase active metal component MoO3 to the bulk phase active metal component MoO3 is 2.7:1 to 6.6:1, and the ratio of the sum of the weight contents of the surface phase active metal components CuO and NiO to the sum of the weight contents of the bulk phase active metal components CuO and NiO is 2.8:1 to 7.3:1; the weight ratio of the graphene in the surface phase to the graphene in the bulk phase is 1.8:1 to 4.5:

1.

2. The hydrofinishing catalyst of claim 1, wherein: The molar ratio of the hydrogenation refining catalyst W / Mo is 1:12 to 10:1, and the molar ratio of Ni / (Mo+W) is 1:12 to 12:

1.

3. The hydrofinishing catalyst of claim 1, wherein: The pore size distribution of the hydrofining catalyst is as follows: the pore volume of the pores with a diameter of 6 nm or less accounts for 2% to 13% of the total pore volume, the pore volume of the pores with a diameter of 6 to 10 nm accounts for 45% to 65% of the total pore volume, the pore volume of the pores with a diameter of 10 to 15 nm accounts for 18% to 40% of the total pore volume, and the pore volume of the pores with a diameter of 15 nm or more accounts for 5% to 22% of the total pore volume; the specific surface area of the hydrofining catalyst is 200 to 500 m 2 / g, and the pore volume is 0.25 to 1.0 mL / g.

4. A process for preparing the hydrofining catalyst according to any one of claims 1 to 3, characterized in that The method comprises the following steps: (1) performing a parallel flow gelation reaction on a W, Mo and Al-containing solution and a first precipitating agent to obtain a first slurry; (2) performing a parallel flow dropwise addition on a Ni-containing solution and a second precipitating agent to the first slurry to perform a gelation reaction to obtain a second slurry; (3) performing n times of aging treatment on the second slurry at a temperature of 60 to 98℃, and each aging treatment process comprises the following steps: first, aging for 0.05 to 0.5 hours at a pH value of 11.0 to 13.5, then adding 1 / n Al- and Cu-containing solution and 1 / n graphene, adjusting the pH value to 8.5 to 10.5, and continuing to age for 0.05 to 0.5 hours; adjusting the pH value to 4.5 to 6.3 and aging for 0.05 to 0.5 hours; finally, adjusting the pH value to 11.0 to 13.5 for the next aging, until the aging treatment is completed, to obtain a third slurry; wherein n is an integer of 2 to 8; (4) performing filtration on the third slurry, drying and shaping the filter cake, and performing washing, drying and calcination on the shaped material to obtain the hydrogenation refining catalyst.

5. The method of claim 4, wherein: In the W, Mo and Al-containing solution of step (1), the weight concentration of W in the form of WO3 is 5 to 120 g / L, the weight concentration of Mo in the form of MoO3 is 5 to 110 g / L, and the weight concentration of Al in the form of Al2O3 is 2 to 90 g / L; wherein, when preparing the W, Mo and Al-containing solution, the tungsten source 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.

6. The method of claim 4, wherein: The gelation reaction conditions of step (1) are as follows: the reaction temperature is 30 to 95℃, the gelation reaction pH value is controlled at 5 to 6, and the reaction time is 0.1 to 1.0 hours.

7. The method of claim 4, wherein: In the Ni-containing solution of step (2), the weight concentration of Ni in the form of NiO is 5 to 130 g / L; when preparing the Ni-containing solution, the nickel source is one or more of nickel sulfate, nickel nitrate and nickel chloride.

8. The method of claim 4, wherein: The first and second precipitants are both alkaline precipitants selected from one or more of sodium hydroxide, potassium hydroxide, potassium carbonate or potassium bicarbonate solution, and the concentration of the precipitants is 7wt%-20wt%.

9. The method of claim 4, wherein: The gelation reaction conditions in step (2) are as follows: the reaction temperature is 30-95℃, the pH value at the end of the reaction is 8.0-10.5, and the reaction time is 0.5-2.5 hours.

10. The method of claim 4, wherein: In the Al and Cu-containing solution in step (3), the weight concentration of Al (calculated as Al2O3) is 5-70g / L, and the weight concentration of Cu (calculated as CuO) is 7-80g / L; when preparing the Al and Cu-containing solution, the aluminum source is one or more of soluble aluminum salts selected from aluminum nitrate, aluminum sulfate and aluminum chloride, and the copper source is one or more of copper-containing nitrate and / or acetate.

11. The method of claim 4, wherein: The graphene in step (3) is one or two of single-layer graphene, double-layer graphene, few-layer graphene or multi-layer graphene; and the graphene is divided into 2-8 equal parts by mass according to the number of aging treatments.

12. The method of claim 4, wherein: In step (3), the Al added by the Al and Cu-containing solution accounts for 5%-55% of the Al (calculated as Al2O3) in the obtained hydrofining catalyst.

13. The method of claim 4, wherein: The drying conditions in step (4) are as follows: drying at 40-150℃ for 1-48 hours; one or more of a peptizing agent and an extrusion aid is added during the molding process; the peptizing agent is one or more of hydrochloric acid, nitric acid, sulfuric acid, acetic acid and oxalic acid; the extrusion aid is a substance that is beneficial to extrusion molding and is selected from one or more of sesbania powder, carbon black, graphite powder and citric acid, and the amount of the extrusion aid is 1wt%-10wt% of the total dry material.

14. The method of claim 4, wherein: The calcination conditions in step (4) are as follows: calcination at 350-650℃ for 1-24 hours.

15. Use of the hydrofining catalyst according to any one of claims 1-3 in the ultra-deep hydrodesulfurization, hydrodenitrogenation and hydrodearomatization of a heavy diesel oil fraction, wherein the content of aromatic hydrocarbons in the heavy diesel oil fraction is 50wt%-85wt%, and the cetane number is less than 24.