Process for the preparation of a special oil hydrocracking catalyst

Abstract

The application discloses a preparation method of a special oil hydrocracking catalyst, and comprises the following contents: (1) a composite precipitator is dropped into an ammonium metatungstate and nickel salt-containing solution to perform a gelation reaction, the pH value is increased n times, an aluminum salt solution and a beta molecular sieve slurry are added each time, an organic phosphorus source is added at the n-1 time; (2) the gelled material is aged m times, and a pH value decreasing process in three stages is performed each time; (3) the solid-phase material after aging is dried, formed, washed, dried again, calcined to obtain a catalyst precursor, and finally hydrogen reduction is performed to obtain the catalyst. According to the method, the adding time and mode of each component material are matched through certain precipitation conditions, a bulk catalyst with large surface-phase phosphide density and good dispersity, strong isomerization performance and high aromatic hydrocarbon conversion capacity is prepared, and the catalyst is suitable for application in a special oil hydrocracking process.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of special oils, and particularly relates to a preparation method of a special oil hydrocracking catalyst. BACKGROUND

[0002] The hydrocracking diesel oil fraction can be blended to produce various white oils, antirust oils, transformer oils, aluminum cold rolling oils and the like. Among them, the industrial white oil has a pour point index of-3 to-9 DEG C according to different grades, and the aromatic hydrocarbon mass content is required to be not more than 5%. The transformer oil has a pour point index in the range of-10 DEG C to-50 DEG C according to different minimum cold operating temperature in actual application, and the polycyclic aromatic hydrocarbon content is required to be less than 3%. According to the product index of the special oil, the hydrocracking catalyst needs to have high isomerization performance and high aromatic conversion capacity at the same time, which requires that the acid component and the hydrogenation active metal component in the hydrocracking catalyst have a good synergistic effect.

[0003] At present, the acid component commonly used in hydrocracking is generally Y molecular sieve, beta molecular sieve, ZSM-5 molecular sieve and the like. The molecular sieve with good isomerization performance can meet the pour point index requirement of the industrial white oil, but it cannot meet the polycyclic aromatic hydrocarbon content requirement of the industrial white oil. The active metal loading of the traditional supported hydrocracking catalyst is generally not more than 30wt% due to the limitation of the pore structure of the carrier, and the hydrogenation activity of the catalyst is far from the aromatic conversion activity required for producing the industrial white oil. The bulk hydrocracking catalyst prepared by the coprecipitation method has a high active metal content, but it often has the problems of uneven dispersion of the active metal, small pore volume and specific surface area of the catalyst, and low utilization rate of the active metal, and it is also difficult to meet the hydrogenation activity requirement for producing the industrial white oil.

[0004] CN111822022A discloses a preparation method of a phosphorus-containing hydrocracking catalyst, which comprises the following contents: (1) preparing a solution A containing Ni and / or W, and preparing a mixed solution B containing Ni and / or W, Si and Al components; (2) performing a parallel flow gelation reaction on the solution A and a sodium metaaluminate alkaline solution to obtain a slurry I, and then aging and filtering; (3) uniformly mixing the filter cake obtained in the step (2), a molecular sieve suspension and the solution B to obtain a mixture A, then adding an ammonia water solution B dropwise into the mixture A to perform a gelation reaction, obtaining a slurry II, adding an organic phosphorus compound into the slurry II, and then aging; (4) drying, shaping and calcining the material obtained in the step (3), and then reducing to obtain a hydrocracking catalyst. The transition metal phosphide particles in the catalyst are small, and the utilization rate of the active metal needs to be improved.

[0005] At present, the phosphide catalyst prepared by the coprecipitation method can greatly increase the number of active centers. However, compared with the supported phosphide catalyst, although the phosphide catalyst prepared by the coprecipitation method has high active metal content, its pore volume and specific surface area are small, and the phosphide particles are of different sizes, which affects the utilization rate of the active metal. In addition, how to make the hydrogenation and isomerization performance of the phosphide and the acidic component in the catalyst better is also a problem to be solved. SUMMARY

[0006] In view of the deficiencies in the prior art, the present application provides a preparation method of a special oil hydrocracking catalyst. The present application method matches the addition time and mode of each component material through certain precipitation conditions, and prepares a bulk phase catalyst with high density and good dispersibility of surface phosphide, strong isomerization performance and high aromatic conversion capacity, which is suitable for application in the production of special oil hydrocracking process.

[0007] The preparation method of the special oil hydrocracking catalyst of the present application comprises the following contents:

[0008] (1) The composite precipitant is dropped into the solution containing ammonium metatungstate and nickel salt to perform a gelation reaction, the pH value is increased successively during the reaction, and after each increase, one portion of aluminum salt solution and one portion of beta molecular sieve slurry are added; the number of times of increase is n times, and at n-1 times, an organic phosphorus source is added, wherein n is an integer of 3-8; after the gelation reaction is completed, a gelation material is obtained;

[0009] (2) The gelation material obtained in step (1) is continuously aged for m times, and each aging process is as follows: in the first stage, 1 / m sodium metaaluminate solution is dropped to control the pH value between 11.5-13.5, and aged for a period of time; in the second stage, the pH value is adjusted to 8.5-10.5, and aged for a period of time; in the third stage, the pH value is adjusted to 4.5-6.3, and aged for a period of time; wherein m is an integer of 2-8;

[0010] (3) The solid material after aging in step (2) is dried, shaped, washed, and then dried and calcined to obtain a catalyst precursor, and finally hydrogen reduction is performed to obtain a catalyst.

[0011] In the present application method, the composite precipitant in step (1) is a mixed solution of ammonia and sodium phosphate solution, wherein the molar ratio of ammonia to sodium phosphate is 0.2:1-0.6:1; the concentration of ammonia water is 5wt%-10wt%, and the concentration of sodium phosphate solution is 8wt%-20wt%.

[0012] In the method, the weight concentration of ammonium metatungstate in the solution containing ammonium metatungstate and nickel salt in step (1) is 10-130 g / L, preferably 15-120 g / L, calculated as WO3; the weight concentration of nickel salt is 5-130 g / L, preferably 10-115 g / L, calculated as NiO; and the nickel salt is one or more of nickel sulfate, nickel nitrate and nickel chloride.

[0013] In the method, the weight concentration of the aluminum salt solution in step (1) is 10-145 g / L, preferably 15-140 g / L, calculated as Al2O3; and the aluminum salt is one or more of aluminum nitrate, aluminum sulfate, aluminum chloride and aluminum acetate. The solution is divided into n parts according to the increasing number of pH values, preferably equal parts by volume.

[0014] In the method, the solid-liquid mass ratio of the beta molecular sieve slurry in step (1) is 1:3-1:9, preferably 1:2.5-1:8.5, of beta molecular sieve and deionized water. The slurry is divided into n parts according to the increasing number of pH values, preferably equal parts by volume. The beta molecular sieve has the following properties: the molar ratio of silicon oxide to aluminum oxide is 30-85; the specific surface area is 350-780 m 2 / g, preferably 450-700 m 2 / g; the pore volume is 0.30-0.80 cm 3 / g, preferably 0.35-0.75 cm 3 / g; and the infrared acid acid amount is 0.10-0.55 mmol / g, preferably 0.18-0.50 mmol / g.

[0015] In the method, the pH value of the gelation reaction in step (1) is increased from 5.0-6.5 to 8.0-10.5, and preferably constant for 0.05-0.5 hours after each increase. The pH value can be increased by the same amount each time, or by different amounts each time, preferably the pH value is increased by no more than the previous pH value.

[0016] In the method, the gelation reaction temperature in step (1) is 40-90℃, and the gelation reaction time is 0.3-5.0 hours.

[0017] In the method, the organic phosphorus source in step (1) is one or more of octadecyl ether phosphate (O-5P), alkyl phenol ether phosphate (TXP-4, TXP-10), isomeric tridecanol ether phosphate (E-1310P), lauryl alcohol ether phosphate (MOA-3P, MOA-9P), castor oil phosphate, octadecyl phosphate, lauryl phosphate, preferably one or more of alkyl phenol ether phosphate (TXP-4, TXP-10), isomeric tridecanol ether phosphate (E-1310P), lauryl alcohol ether phosphate (MOA-3P, MOA-9P), castor oil phosphate. The amount of the added phosphate compound is 0.6:1 to 3.0:1, preferably 0.8:1 to 2.5:1, in terms of the molar ratio of Al in the Al-containing solution in step (2). The organic phosphorus source is divided into 2 to 8 parts in terms of mass according to the number of times of pH increase, preferably equally divided in terms of mass.

[0018] In the method, the weight concentration of Al (calculated as Al2O3) in the sodium metaaluminate solution in step (2) is 5 to 70 g / L, preferably 8 to 60 g / L. The sodium metaaluminate solution is divided into m parts in terms of volume according to the number of times of addition, preferably equally divided in terms of volume, m is an integer of 2 to 8, preferably equally divided in terms of volume.

[0019] In the method, the aging temperature in step (2) is 60 to 98°C, preferably 65 to 92°C.

[0020] In the method, in addition to the sodium metaaluminate solution used for adjusting the pH value in the first stage, the acid and base used for adjusting the pH value in the remaining stages 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, ammonia water and sodium hydroxide, and the concentration and amount of the acid and base solution can be adjusted according to the actual preparation needs.

[0021] In the method, the Al added by the sodium metaaluminate solution accounts for 5% to 55%, preferably 6% to 50%, of the Al in the catalyst in terms of Al2O3.

[0022] In the method of the present application, the drying, shaping and washing in step (3) can be carried out by using conventional methods. The drying conditions are as follows: drying at 40-150°C for 1-48 hours, preferably at 50-120°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. The extrusion aid refers to a substance that is beneficial to extrusion shaping, such as one or more of sesbania powder, carbon black, graphite powder, citric acid, etc. The amount of the extrusion aid is 1wt%-10wt% of the total material dry basis. The washing is generally carried out using deionized water or a solution containing decomposable salts (such as ammonium acetate, ammonium chloride, ammonium nitrate, etc.) until neutral.

[0023] In the method of the present application, the calcination conditions in step (3) are as follows: calcination at 350-700°C for 1-24 hours, preferably at 400-650°C for 2-12 hours.

[0024] In the method of the present application, the reduction process in step (3) is carried out in a hydrogen atmosphere. In the first stage, the temperature is raised at a rate of 3-10°C / min from room temperature to 300-550°C, and then kept constant for 1-5 hours. In the second stage, the temperature is raised at a rate of 0.5-5°C / min to 600-750°C, and then kept constant for 2-8 hours. The temperature raising rate in the second stage is lower than that in the first stage by more than 1°C / min, preferably at least more than 2°C / min. The purity of hydrogen is greater than 99v%; the flow rate of hydrogen is 150-700mL / min, preferably 250-600mL / min.

[0025] In the method of the present application, the shape of the catalyst can be sheet, spherical, cylindrical strip, and irregular strip (three-leaf clover, four-leaf clover) as needed, preferably cylindrical strip and irregular strip (three-leaf clover, four-leaf clover). The diameter of the catalyst can be 0.8-2.0mm thin strip and >2.5mm thick strip.

[0026] In the method of the present application, to prevent the phosphide from undergoing violent oxidation reaction when it contacts with air, the prepared catalyst sample is first passivated with O2 / N2 passivation gas with an oxygen volume concentration of 0.5%-3% for 1-5 hours before it contacts with air.

[0027] The application also provides a special oil hydrocracking catalyst, wherein the total content of transition metal phosphide is 15wt%-70wt%, preferably 18wt%-68wt%, the content of beta molecular sieve is 5wt%-20wt%, preferably 6wt%-18wt%, the content of amorphous alumina is 15wt%-65wt%, preferably 20wt%-60wt%, the transition metal phosphide is WP and Ni2P, the weight ratio of Ni2P in the surface phase and the bulk phase is 2.6:1-7.0:1, preferably 2.5:1-6.5:1, the weight ratio of WP in the surface phase and the bulk phase is 2.3:1-6.3:1, preferably 2.5:1-5.8:1, and the molar ratio of Ni / W is 0.1:1-14:1, preferably 0.2:1-12:1.

[0028] In the catalyst, the average particle diameter of the transition metal phosphide is 2-6nm, preferably 3-7nm.

[0029] The specific surface area of the catalyst is 150-700m 2 / g, the pore volume is 0.25-1.2mL / g, the pore size distribution is as follows: the pore volume of the pores with a diameter of less than 6nm accounts for 3%-13% of the total pore volume, the pore volume of the pores with a diameter of 6-10nm accounts for 50%-73% of the total pore volume, the pore volume of the pores with a diameter of 10-15nm accounts for 8%-25% of the total pore volume, and the pore volume of the pores with a diameter of more than 15nm accounts for 7%-22% of the total pore volume.

[0030] Compared with the prior art, the application has the following advantages:

[0031] 1. In the application, the metal components of the catalyst are precipitated by using the pH value increasing gelation method at a specific pH value, so that the generation of large particle oxides in the gelation process is prevented.

[0032] 2、The application adopts inorganic phosphorus source and organic phosphorus source, the sodium phosphate in the first step is used as a gelation reactant to make the phosphorus distribute uniformly, the organic phosphorus source added in the second step can not only make the surface active metal disperse uniformly and the phosphorus distribute uniformly on the surface of the catalyst, but also can weaken the interaction between W, Ni, P and the carrier, so that W and Ni are easy to be phosphorized, the two kinds of phosphorus sources interact with each other, the transition active metal in the bulk phase catalyst can be fully phosphorized, and the phosphorides are prevented from gathering on the surface of the catalyst. Meanwhile, the sodium phosphate and ammonia water are used as a composite precipitator to control the properties of the generated materials, the metal oxide particle size is small and uniform, the generated phosphoride particle size is small, the pore volume and specific surface area of the bulk phase catalyst are increased, and the suitable pore size can improve the diffusion efficiency of the catalytic process.

[0033] 3、The application swings the pH value during aging, and the sodium meta-aluminate solution is added in several times, the amorphous oxide in the oxide particles is dissolved by the pH value swing, the size of the oxide particles is modified by adding the sodium meta-aluminate solution, the growth of the oxide particles is controlled through the pH value swing for m times, the oxide particles are more uniform, the particle size is small, more active metals are exposed on the surface, the large pores in the bulk phase catalyst are increased, the macromolecular reactants are easy to pass through the pores, meanwhile, the aluminum introduced by the sodium meta-aluminate solution increases the surface hydroxyl, the adhesion of the oxide is further enhanced, and the catalyst molding is beneficial.

[0034] The hydrogen cracking catalyst prepared by the preparation method has high aromatic saturation reaction performance, high isomerization performance and high aromatic conversion capacity, and is used in the process of producing special oil through hydrogen cracking, so that the aromatic content and pour point of the hydrogen cracking diesel oil fraction product can meet the requirements of the 5th industrial grade white oil and high viscosity index lubricating oil base oil raw materials. DETAILED DESCRIPTION

[0035] In the application, the specific surface area, pore volume and pore distribution are determined by the low-temperature liquid nitrogen adsorption method, the mechanical strength is determined by the side pressure method, and the diameter of the transition metal phosphide particles is determined by the TEM technology. In the application, wt% is the mass fraction, and v% is the volume fraction.

[0036] The content of the catalyst surface phase phosphide is determined by the X-ray photoelectron spectroscopy (XPS), and the content of the catalyst bulk phase phosphide is determined by the inductively coupled plasma atomic emission spectroscopy (ICP-AES). First, the surface phase and bulk phase active metal contents of the transition metal oxide precursor of the catalyst are determined, and then the contents of the transition metal phosphide in the surface phase and the bulk phase of the catalyst are converted. In the application, the properties of the β molecular sieve are shown in Table 5. Example 1

[0037] Ammonium metatungstate and nickel chloride were added into a dissolving tank 1 containing deionized water to prepare a W and Ni containing solution, the weight concentration of W in the W and Ni containing solution was 32 g / L as WO3, and the weight concentration of Ni was 60 g / L as NiO. An Al containing solution was prepared, the weight concentration of Al in the Al containing solution was 58.8 g / L as Al2O3, and the Al containing solution was divided into 5 equal parts by volume. The Al in the sodium aluminate solution accounted for 30% of the total Al (as Al2O3) in the obtained hydrocracking catalyst, and the sodium aluminate solution was divided into 5 equal parts by volume. A β-molecular sieve slurry was prepared by mixing β-molecular sieve and deionized water at a solid-liquid mass ratio of 6.0, and the β-molecular sieve slurry was divided into 5 equal parts by volume. Deionized water was placed in a reaction tank, the W and Ni containing solution was placed in the reaction tank, the reaction temperature was 60°C, and ammonia water and sodium phosphate solution were added dropwise, the molar ratio of ammonia to sodium phosphate in the ammonia water and sodium phosphate solution was 0.28:1, the pH value was controlled to be 5.2, the ammonia water and sodium phosphate solution were continuously added dropwise, the pH value was increased by 0.8 each time through 5 times of pH value increase, and the final pH value at the end of the reaction was adjusted to be 9.2. After the pH value was adjusted each time, one part of the Al containing solution and one part of the β-molecular sieve slurry were added, the pH value of the adjusted reaction slurry was kept constant for 10 minutes, castor oil phosphate was added when the pH value started to be increased for the fourth time, the molar ratio of castor oil phosphate to the total number of Al atoms in the Al containing solution was 1.1, a precipitate slurry containing nickel, tungsten, aluminum and molecular sieve was generated, the obtained slurry was aged, the aging temperature was 76°C, one part of the sodium aluminate solution was added first during the aging, the pH value was controlled to be 13.3, the aging time was 0.15 hours, then the aging pH value was controlled to be 9.3, the aging time was 0.2 hours, then the pH value was controlled to be 5.2, the aging time was 0.15 hours, the above operation process was repeated 5 times, and the aging was completed. The aged slurry was filtered, the filter cake was dried at 100°C for 8 hours, was rolled and pressed, and was extruded into a strip. The extruded material was washed with deionized water at room temperature until neutral. The washed and formed material was dried at 80°C for 9.0 hours, the dried material was calcined at 530°C for 5 hours to obtain a phosphide catalyst precursor A. The precursor A was heated in a pure hydrogen atmosphere, the hydrogen flow rate was 320 mL / min, the heating rate was 7°C / min, the temperature was increased from room temperature to 430°C, the temperature was kept constant for 3.0 hours, then the temperature was increased to 700°C at a heating rate of 3.0°C / min, and the temperature was kept constant for 5 hours. In order to prevent the phosphide from reacting violently with air due to oxidation, the catalyst sample was passivated with O2 / N2 passivation gas with an oxygen volume concentration of 2% for 3 hours before the catalyst sample contacted with air to obtain a hydrofining catalyst A. The catalyst composition and main physicochemical properties are shown in Table 1. Example 2

[0038] Ammonium metatungstate and nickel chloride were added to a dissolving tank 1 containing deionized water to prepare a solution containing W and Ni. The weight concentration of W in the form of WO3 in the solution containing W and Ni was 40 g / L, and the weight concentration of Ni in the form of NiO was 48 g / L. A solution containing Al was prepared, and the weight concentration of Al in the form of Al2O3 was 57 g / L. The solution containing Al was divided into six equal parts by volume. The Al in the sodium metaluminate solution accounted for 35% of the total Al (in the form of Al2O3) in the obtained hydrocracking catalyst, and the solution was divided into six equal parts by volume. A β-molecular sieve slurry was prepared by mixing β-molecular sieve and deionized water at a solid-to-liquid mass ratio of 6.0, and the slurry was divided into six equal parts by volume. Deionized water was placed in a reaction tank, and the solution containing W and Ni was placed in the reaction tank. The reaction temperature was 65°C. Ammonia water and a sodium phosphate solution were added dropwise. The molar ratio of ammonia to sodium phosphate in the ammonia water and the sodium phosphate solution was 0.33:1. The pH value was controlled to be 5.1. The ammonia water and the sodium phosphate solution were continuously added dropwise. The pH value was adjusted to 9.9 at the end of the process by increasing the pH value six times. The pH value was increased by 0.8 each time. After the pH value was adjusted each time, one part of the solution containing Al and one part of the β-molecular sieve slurry were added. The pH value of the adjusted reaction slurry was kept constant for 12 minutes. When the pH value was increased for the fifth time, lauryl alcohol ether phosphoric acid ester was added. The molar ratio of lauryl alcohol ether phosphoric acid ester to the total number of Al atoms in the solution containing Al was 1.7. A precipitate slurry containing nickel, tungsten, and aluminum was generated. The obtained slurry was aged. The aging temperature was 80°C. During the aging process, one part of the sodium metaluminate solution was added first, and the pH value was controlled to be 13.0. After 0.15 hours, the pH value was controlled to be 9.3. After 0.15 hours, the pH value was controlled to be 5.0. After 0.15 hours, the above process was repeated six times, and the aging process was ended. The aged slurry was filtered. The filter cake was dried at 80°C for 9 hours. The filter cake was rolled and extruded into a strip. The extruded material was washed with deionized water at room temperature until the material was neutral. The washed and formed material was dried at 80°C for 9.0 hours. The dried material was calcined at 520°C for 5 hours to obtain a phosphide catalyst precursor B. The precursor B was subjected to a calcination process in a pure hydrogen atmosphere. The hydrogen flow rate was 350 mL / min. The temperature was increased from room temperature to 460°C at a rate of 5°C / min. After the temperature was kept constant at 460°C for 3.5 hours, the temperature was increased to 660°C at a rate of 3.0°C / min. The temperature was kept constant at 660°C for 6 hours. To prevent the phosphide from reacting violently with air due to oxidation, the catalyst sample was passivated with O2 / N2 passivation gas with an oxygen volume concentration of 2.5% for 3.5 hours before the catalyst sample was exposed to air to obtain a hydrofining catalyst B. The composition and main physicochemical properties of the catalyst are shown in Table 1. Example 3

[0039] Ammonium metatungstate and nickel chloride were added to a dissolving tank 1 containing deionized water to prepare a solution containing W and Ni. The weight concentration of W in the form of WO3 in the solution containing W and Ni was 28 g / L, and the weight concentration of Ni in the form of NiO was 64 g / L. A solution containing Al was prepared, and the weight concentration of Al in the form of Al2O3 was 64.5 g / L. The solution containing Al was divided into five equal parts by volume. The Al in the sodium aluminate solution accounted for 25% of the total Al (in the form of Al2O3) in the obtained hydrocracking catalyst, and the solution was divided into six equal parts by volume. A β-molecular sieve slurry was prepared by mixing β-molecular sieve and deionized water at a solid-to-liquid mass ratio of 6.0, and the slurry was divided into six equal parts by volume. Deionized water was placed in a reaction tank, and the solution containing W and Ni was placed in the reaction tank. The reaction temperature was 55°C. Ammonia water and a sodium phosphate solution were added dropwise. The molar ratio of ammonia to sodium phosphate in the ammonia water and the sodium phosphate solution was 0.38:1. The pH value was controlled to be 5.2. The ammonia water and the sodium phosphate solution were continuously added dropwise. The pH value was adjusted to 8.7 at the end of the process by five times of pH value adjustment. The pH value was adjusted by 0.7 each time. After the pH value was adjusted to the adjusted value each time, one part of the solution containing Al and one part of the β-molecular sieve slurry were added. The pH value of the adjusted reaction slurry was kept constant for 13 minutes. At the beginning of the fourth pH value adjustment, octadecyl ether phosphate was added. The molar ratio of octadecyl ether phosphate to the total number of Al atoms in the solution containing Al was 1.4. A precipitate slurry containing nickel, tungsten and aluminum was generated. The obtained slurry was aged. The aging temperature was 81°C. During the aging, one part of the sodium aluminate solution was added first, and the pH value was controlled to be 12.7. After 0.15 hours of aging, the pH value was controlled to be 9.8. After 0.18 hours of aging, the pH value was controlled to be 5.1. After 0.2 hours of aging, the above operation was repeated six times, and the aging was ended. The aged slurry was filtered. The filter cake was dried at 80°C for 1 hour, crushed, and extruded into a strip. The extruded material was washed with deionized water at room temperature until neutral. The washed extruded material was dried at 110°C for 9.0 hours. The dried material was calcined at 520°C for 5 hours to obtain a phosphide catalyst precursor C. The precursor C was subjected to hydrogenation under a pure hydrogen atmosphere. The hydrogen flow rate was 450 mL / min. The temperature was increased from room temperature to 430°C at a rate of 6°C / min. After the temperature was kept constant at 430°C for 3.8 hours, the temperature was increased to 670°C at a rate of 3.5°C / min. The temperature was kept constant at 670°C for 4.6 hours. To prevent the phosphide from undergoing a violent oxidation reaction with air, the catalyst sample was passivated with O2 / N2 passivation gas with an oxygen volume concentration of 2.5% for 4 hours before the catalyst sample was exposed to air to obtain a hydrofining catalyst C. The catalyst composition and main physicochemical properties are shown in Table 1. Example 4

[0040] Ammonium metatungstate and nickel chloride were added to a dissolving tank 1 containing deionized water to prepare a W and Ni-containing solution, in which the weight concentration of W (calculated as WO3) was 24 g / L and the weight concentration of Ni (calculated as NiO) was 70 g / L. An Al-containing solution was prepared, in which the weight concentration of Al (calculated as Al2O3) was 56 g / L, and the solution was divided into five equal parts by volume. The Al in the sodium metaluminate solution accounted for 33% of the total Al (calculated as Al2O3) in the obtained hydrocracking catalyst, and the solution was divided into six equal parts by volume. A β molecular sieve slurry was prepared by mixing the β molecular sieve and deionized water at a solid-liquid mass ratio of 6.0, and the slurry was divided into six equal parts by volume. Deionized water was placed in a reaction tank, and the W and Ni-containing solution was placed in the reaction tank. The reaction temperature was 68℃. Ammonia water and sodium phosphate solution were added dropwise, and the molar ratio of ammonia to sodium phosphate in the ammonia water and sodium phosphate solution was 0.32:1. The pH value was controlled to be 5.3. The ammonia water and sodium phosphate solution were continuously added dropwise. The pH value was adjusted to 9.3 at the end of the process by adjusting the pH value up by 0.8 for five times. After each adjustment, one part of the Al-containing solution and one part of the β molecular sieve slurry were added. The pH value of the adjusted reaction slurry was kept constant for 15 minutes. When the pH value was adjusted up for the fourth time, isomeric tridecanol ether phosphate was added. The molar ratio of isomeric tridecanol ether phosphate to the total number of Al atoms in the Al-containing solution was 1.6. A precipitate slurry containing nickel, tungsten and aluminum was generated. The obtained slurry was aged. The aging temperature was 82℃. During the aging process, one part of the sodium metaluminate solution was added first, and the pH value was controlled to be 13.2. After 0.2 hours of aging, the aging pH value was controlled to be 9.4. After 0.15 hours of aging, the pH value was controlled to be 4.9. After 0.2 hours of aging, the above process was repeated six times, and the aging was completed. The aged slurry was filtered, the filter cake was dried at 100℃ for 9 hours, was rolled and was extruded into a strip. The extruded material was washed with deionized water at room temperature until it was neutral. The washed and formed material was dried at 85℃ for 9.5 hours. The dried material was calcined at 540℃ for 4 hours to obtain a phosphide catalyst precursor D. The precursor D was heated in a pure hydrogen atmosphere at a hydrogen flow rate of 390 mL / min, at a heating rate of 6 ℃ / min from room temperature to 470 ℃, and was kept at 470 ℃ for 4.0 hours. Then, the temperature was increased to 680 ℃ at a heating rate of 3.5 ℃ / min, and was kept at 680 ℃ for 5 hours. To prevent the phosphide from reacting violently with air due to oxidation, the catalyst sample was passivated with O2 / N2 passivation gas with an oxygen volume concentration of 2.2% for 4 hours before the catalyst sample was exposed to air to obtain a hydrofining catalyst D. The composition and main physicochemical properties of the catalyst are shown in Table 1.

[0041] Comparative Example 1

[0042] A hydrocracking catalyst E was prepared according to the method of Example 1 of CN111822035A, and the acid component was a β molecular sieve. The specific process was as follows:

[0043] Nickel nitrate was added to a dissolving tank 1 containing deionized water, and a dilute water glass solution was added to prepare a mixed solution A. The weight concentration of Ni in the mixed solution A, calculated as NiO, was 40 g / L, and the weight concentration of Si, calculated as SiO2, was 10 g / L. Ammonium metatungstate was added to a dissolving tank 2 containing deionized water, and a dilute water glass solution was added to prepare a mixed solution B. The weight concentration of W in the mixed solution B, calculated as WO3, was 38 g / L, and the weight concentration of Si, calculated as SiO2, was 15.5 g / L. Deionized water was added to a reaction tank, and a sodium metaaluminate solution with a weight concentration of 20 g / L, calculated as Al2O3, and the mixed solution A were added to the reaction tank in parallel flow. The gelation temperature was maintained at 58°C, the pH value during the parallel flow gelation reaction was controlled at 7.6, the gelation time was controlled at 1.0 hour, and slurry I was obtained. The obtained precipitate slurry I was aged under stirring at a stirring speed of 220 r / min, the aging temperature was 75°C, the pH value during the aging was controlled at 7.2, and the aging time was 0.6 hour. After the aging was completed, the mixed solution B, a sodium metaaluminate solution with a weight concentration of 15 g / L, calculated as Al2O3, and a β molecular sieve suspension were added to the slurry I in parallel flow. The gelation temperature was maintained at 58°C, the pH value during the parallel flow gelation reaction was controlled at 8.7, and the gelation time was controlled at 2.8 hours. The precipitate slurry II was obtained, and the amount of the β molecular sieve added was 10 wt% based on the total weight of the catalyst. The properties of the β molecular sieve are shown in Table 4. Diethylene triamine penta methylene phosphonic acid was added to the precipitate slurry II, and the molar ratio of diethylene triamine penta methylene phosphonic acid to the nickel transition metal in the catalyst was 4.5:1. The precipitate slurry II was aged under stirring at a stirring speed of 410 r / min, the aging temperature was 75°C, the pH value was controlled at 9.0, and the aging time was 3.7 hours. The obtained material was dried at 130°C for 12 hours, and then shaped. The shaped material was calcined at 530°C for 5 hours to obtain a phosphide catalyst precursor E. The precursor E was subjected to a reduction treatment in a pure hydrogen atmosphere at a hydrogen flow rate of 320 mL / min and a temperature increasing rate of 6°C / min from room temperature to 450°C. After the temperature was kept at 450°C for 4.0 hours, the temperature was increased to 630°C at a temperature increasing rate of 3.0°C / min, and then kept at 630°C for 3 hours. In order to prevent the phosphide from being subjected to a severe oxidation reaction with air, the catalyst sample was subjected to a passivation treatment with a O2 / N2 passivation gas with an oxygen volume concentration of 1.1% for 1.3 hours before the catalyst sample was exposed to air to obtain a hydrocracking catalyst E. In the hydrocracking catalyst E, the weight of the nickel introduced through the mixed solution A accounted for 70% of the total weight of the nickel and tungsten in the hydrocracking catalyst E, and the weight of Al in the precipitate I accounted for 60% of the total weight of Al in the hydrocracking catalyst E. The catalyst composition and the main physicochemical properties are shown in Table 1.

[0044] Comparative Example 2

[0045] A reference agent F was prepared according to Example 1, and the molar ratio of ammonia, calculated as NH3, to sodium phosphate was 0.8:1.

[0046] Comparative Example 3

[0047] The same as Example 1, Reference G was prepared, the sodium metaaluminate solution was added all at the beginning of the aging reaction, the pH value of the aging reaction was controlled by a fixed value, and the preparation process was as follows:

[0048] Ammonium metatungstate and nickel chloride were added into a dissolving tank 1 containing deionized water to prepare W and Ni-containing solutions, the weight concentration of W in the W and Ni-containing solutions was 32 g / L as WO3, and the weight concentration of Ni was 60 g / L as NiO. An Al-containing solution was prepared, the weight concentration of Al was 58.8 g / L as Al2O3, and it was divided into 5 equal parts by volume. The Al in the sodium metaaluminate solution accounted for 30% of the total Al (as Al2O3) in the obtained hydrocracking catalyst. The β molecular sieve and deionized water were mixed to prepare a β molecular sieve slurry at a solid-liquid mass ratio of 6.0, and the slurry was divided into 5 equal parts by volume. Deionized water was placed in a reaction tank, the W and Ni-containing solution was placed in the reaction tank, the reaction temperature was 60°C, and ammonia water and sodium phosphate solution were added dropwise, the molar ratio of ammonia to sodium phosphate in the ammonia water and sodium phosphate solution was 0.28:1, the pH value was controlled to be 5.2, the ammonia water and sodium phosphate solution were continuously added dropwise, the pH value was increased by 0.8 each time through 5 times of pH value increase, and the final pH value at the end was adjusted to 9.2. After each adjustment, one part of the Al-containing solution and one part of the β molecular sieve slurry were added, the adjusted reaction slurry pH value was kept constant for 10 minutes. At the beginning of the fourth pH value increase, castor oil phosphate was added, the molar ratio of castor oil phosphate to the total number of Al atoms in the Al-containing solution was 1.1, a precipitate slurry containing nickel, tungsten, aluminum and molecular sieve was generated, the obtained slurry was aged, the aging temperature was 76°C, all the sodium metaaluminate solution was added at the beginning of the aging, the pH value was controlled to be 8.3, the aging time was 2.0 hours, and the aging was ended. The aged slurry was filtered, the filter cake was dried at 100°C for 8 hours, was rolled and pressed, and was extruded into a strip. The strip was washed with deionized water at room temperature until it was neutral. The washed and formed material was dried at 80°C for 9.0 hours, the dried material was calcined at 530°C for 5 hours, and a phosphide catalyst precursor G was obtained. The precursor G was heated in a pure hydrogen atmosphere, the hydrogen flow rate was 320 mL / min, the heating rate was 7°C / min, the temperature was increased from room temperature to 430°C, the temperature was kept constant for 3.0 hours, the temperature was increased to 700°C at a heating rate of 3.0°C / min, and the temperature was kept constant for 5 hours. To prevent the phosphide from reacting violently with air due to oxidation, the catalyst sample was passivated with O2 / N2 passivation gas with an oxygen volume concentration of 2% for 3 hours before it was exposed to air, and a hydrofining catalyst G was obtained. The catalyst composition and main physicochemical properties are shown in Table 1.

[0049] Comparative Example 4

[0050] The same as Example 1, Reference H was prepared using ammonia water as a precipitant.

[0051] Comparative Example 5

[0052] Example 1 was repeated, using sodium phosphate solution as precipitant to prepare Reference Catalyst I.

[0053] Comparative Example 6

[0054] Example 1 was repeated, except that the solution containing aluminum was not prepared separately. The solution containing tungsten, nickel and aluminum was prepared according to the content of aluminum oxide in the solution containing aluminum. The pH value was not increased step by step during the reaction, but was fixed to carry out the gelation reaction. The β-molecular sieve slurry and the castor oil phosphate were added at the end of the reaction to prepare Reference Catalyst J.

[0055] Ammonium metatungstate and nickel chloride were added into a dissolving tank 1 containing deionized water to prepare a solution containing W, Ni and Al. The weight concentration of W in the solution containing W, Ni and Al, calculated as WO3, was 32 g / L, the weight concentration of Ni, calculated as NiO, was 60 g / L, and the weight concentration of Al, calculated as Al2O3, was 58.8 g / L. The Al in the sodium metaaluminate solution accounted for 30% of the total Al (calculated as Al2O3) in the obtained hydrocracking catalyst, and the sodium metaaluminate solution was divided into 5 equal parts by volume. The β-molecular sieve slurry was prepared according to a solid-liquid mass ratio of 6.0 from β-molecular sieve and deionized water. Deionized water was placed in a reaction tank, and the solution containing W, Ni and Al was placed in the reaction tank. Ammonia water and sodium phosphate solution were added dropwise, and the molar ratio of ammonia to sodium phosphate in the ammonia water and sodium phosphate solution was 0.28:1. The pH value was controlled at 9.2 at the end of the reaction. The β-molecular sieve slurry and castor oil phosphate were added at the end of the reaction. The molar ratio of castor oil phosphate to the total number of Al atoms in the solution containing Al was 1.1. A precipitate slurry containing nickel, tungsten, aluminum and molecular sieve was generated. The obtained slurry was aged. The aging temperature was 76°C. At the beginning of the aging, one part of the sodium metaaluminate solution was added, and the pH value was controlled at 13.3. The aging time was 0.15 hours. Then, the aging pH value was controlled at 9.3 after 0.2 hours of aging. Subsequently, the pH value was controlled at 5.2 after another 0.15 hours of aging. The above process was repeated 5 times to complete the aging. The aged slurry was filtered, and the filter cake was dried at 100°C for 8 hours, crushed, and extruded into a strip. The strip was washed with deionized water at room temperature until neutral. The washed strip was dried at 80°C for 9.0 hours. The dried material was calcined at 530°C for 5 hours to obtain a phosphide catalyst precursor J. The precursor J was subjected to a heat treatment in a pure hydrogen atmosphere. The hydrogen flow rate was 320 mL / min, the temperature was increased from room temperature to 430°C at a rate of 7°C / min, and then held at 430°C for 3.0 hours. The temperature was increased to 700°C at a rate of 3.0°C / min, and then held at 700°C for 5 hours. To prevent the phosphide from undergoing a violent oxidation reaction with air, the catalyst sample was passivated with a 2% O2 / N2 passivation gas for 3 hours before being exposed to air to obtain a hydrofining catalyst J. The composition and main physicochemical properties of the catalyst are shown in Table 1. Example 5

[0056] The present embodiment is catalyst activity evaluation experiment of the present application, and comparison with comparative catalyst. Respectively, the present application catalyst A, B, C, D and comparative catalyst E, F, G, H, I, J, in 200ml small hydrogenation device, comparison and evaluation test, in 200ml small hydrogenation device, comparison and evaluation test, evaluation condition is: total pressure 15.7MPa, hydrogen oil volume ratio 1200:1, liquid time volume space velocity 1.7h -1 , reaction temperature 375℃, the evaluation of raw material is vacuum gas oil, its main property is seen in table 4, evaluation result is seen in table 5~6. From table 1~2 can be seen, the present application catalyst phosphide particle average particle size is smaller, the content of phase phosphide, more and dispersion is good, has higher aromatic hydrocarbon saturation performance, acid component and hydrogenation component has good synergistic effect. The present application catalyst in the treatment of heavy oil hydrocracking process, has higher isomerization performance and high aromatic hydrocarbon saturation performance, can produce 5 industrial grade white oil and lubricating oil base oil, comparative catalyst can not have high isomerization performance and high aromatic hydrocarbon saturation performance simultaneously.

[0057] Table 1 Catalyst composition and properties prepared by example and comparative example

[0058] Catalyst No. A B C D E F Catalyst composition [Ni2P, wt%] 30 24 32 35 35 30 WP, wt% 16 20 14 12 15 16 SiO2, wt% 12 12 11 11 24 12 Al203, wt% 42 44 43 42 26 42 Catalyst properties Specific surface area, m 2 / g]] 430 436 420 440 424 212 Pore volume, mL / g 0.454 0.461 0.443 0.469 0.449 0.305 Pore distribution < 6 nm 7.23 7.01 8.32 6.13 31.45 42.37 6 nm ~ 10 nm 63.15 62.95 62.81 63.46 27.23 35.24 10 nm ~ 15 nm 15.65 15.91 15.23 16.21 30.56 12.12 > 15 nm 13.97 14.13 13.64 14.20 10.66 9.27 Average transition metal phosphide particle diameter, nm 6.0 5.8 6.1 6.3 7.0 16.8

[0059] Table 1 Catalyst composition and properties prepared by example and comparative example

[0060] Catalyst No. G H I J Catalyst composition [Ni2P, wt%] 30 30 30 30 WP, wt% 16 16 16 16 SiO2, wt% 12 12 12 12 Al203, wt% 42 42 42 42 Catalyst properties Specific surface area, m 2 / g]] 235 175 402 246 Pore volume, mL / g 0.367 0.272 0.422 0.382 Pore distribution < 6 nm 38.61 63.32 7.51 35.21 6 nm ~ 10 nm 39.47 19.04 62.46 37.44 10 nm ~ 15 nm 11.43 9.92 16.05 13.23 > 15 nm 10.49 7.72 13.98 14.02 Average transition metal phosphide particle diameter, nm 17.1 11.4 25.1 18.7

[0061] Table 2 Weight content ratio of catalyst surface phase and bulk phase active metal oxide

[0062] Catalyst No. A B C D E F Table phase I Ni2P Bulk phase I Ni2P ]]> 5.76 5.89 5.65 5.99 1.36 2.18 Table phase I WP Bulk phase I WP ]]> 4.68 4.77 4.60 4.88 1.19 1.69

[0063] Table 2 Weight content ratio of catalyst surface phase and bulk phase active metal oxide

[0064] Catalyst No. G H I J Table phase I Ni2P Bulk phase I Ni2P ]]> 2.18 2.03 2.14 2.26 Table phase I WP Bulk phase I WP ]] 1.69 1.54 1.65 1.81

[0065] Table 3 Main properties of raw oil

[0066] Feed oil Middle East vacuum gas oil Density (20°C) / g-cm -3 ]] 0.9287 Distillation range, °C IBP / EBP 319 / 535 S, wt% 2.12 N, wt% 0.45 BMCI value 52.1 Mass spectrum composition, wt% Paraffins 19.1 Naphthenes 29.6 Aromatics 51.3

[0067] Table 4 Evaluation results of example and comparative example catalyst

[0068] Catalyst A B C D E F G H I J 82 ~ 132 °C heavy naphtha Arom., wt% 58.1 58.0 58.3 57.8 59.2 61.2.3 60.6 61.8 61.0 60.8 132 ~ 282 °C aviation kerosene Smoke point, mm 29.5 29.8 29.3 29.9 27.8 24.6 25.4 23.6 25.2 25.0 Aromatics, v% 1.9 1.7 2.2 1.5 10.2 17.9 15.6 22.4 16.8 16.1 282 ~ 370 °C diesel Pour point, °C -7 -7 -8 -7 -7 -7 -7 -7 -8 -7 Aromatics, wt% 2.2 2.1 2.4 1.7 9.9 17.8 14.8 20.6 15.7 15.6 > 370 °C tail oil BMCI value 5.9 5.7 6.3 5.4 11.2 21.2 18.2 24.0 19.9 18.8 Viscosity index 124 125 122 127 101 90 96 86 92 94

[0069] Table 5 Properties of β molecular sieve in example and comparative example

[0070] Si / Al molar ratio 80.5 Specific surface area, m 2 / g]] 621 Pore volume, mL / g 0.55 Infrared total acid, mmol / g 0.43 Na2O, wt% 0.080

Claims

1. A method for preparing a special oil hydrocracking catalyst, characterized in that... The following contents are included: (1) The composite precipitant is dropped into a solution containing ammonium metatungstate and nickel salt to carry out a gelling reaction. During the reaction, the pH value is gradually increased. After each increase, one part of aluminum salt solution and one part of β molecular sieve slurry are added. The number of increases is n times. When n-1 times, an organic phosphorus source is added, where n is an integer from 3 to 8. After the gelling reaction is completed, the gelling material is obtained; (2) The gelling material obtained in step (1) is continuously aged m times. Each aging process is as follows: In the first stage, 1 / m sodium metaaluminate solution is dropped in to control the pH value between 11.5 and 13.5 and the aging is carried out for a period of time; In the second stage, the pH value is adjusted to 8.5~10.5 and aged for a period of time; in the third stage, the pH value is adjusted to 4.5~6.3 and aged for a period of time. Where m is an integer from 2 to 8; (3) The solid material after aging in step (2) is dried, shaped, washed, dried and calcined to obtain the catalyst precursor, and finally reduced with hydrogen to obtain the catalyst; The composite precipitant mentioned in step (1) is a mixed solution of ammonia and sodium phosphate, wherein the molar ratio of ammonia to sodium phosphate is 0.2:1 to 0.6:1; the concentration of ammonia is 5wt% to 10wt% and the concentration of sodium phosphate is 8wt% to 20wt%.

2. The method according to claim 1, characterized in that: In step (1), the solution containing ammonium metatungstate and nickel salt has a weight concentration of 10-130 g / L (WO3) and a weight concentration of 5-130 g / L (NiO). The nickel salt is one or more of nickel sulfate, nickel nitrate, and nickel chloride.

3. The method according to claim 1, characterized in that: The aluminum salt solution in step (1) has a weight concentration of 10-145 g / L based on Al2O3; the aluminum salt is one or more of aluminum nitrate, aluminum sulfate, aluminum chloride and aluminum acetate; and is divided into n parts by volume according to the number of pH increments.

4. The method according to claim 1, characterized in that: In step (1), the solid-liquid mass ratio of β-molecular sieve to deionized water in the β-molecular sieve slurry is 1:3 to 1:9; it is divided into n parts by volume according to the number of pH increases; the β-molecular sieve has the following properties: the molar ratio of silicon oxide to aluminum oxide is 30 to 85; the specific surface area is 350 to 780 m². 2 / g; pore volume is 0.30~0.80cm³ 3 / g; the infrared acid concentration is 0.10~0.55mmol / g.

5. The method according to claim 1, characterized in that: The pH value of the gelation reaction in step (1) increases from 5.0 to 6.5 to 8.0 to 10.

5.

6. The method according to claim 1, characterized in that: The pH value of the gelation reaction described in step (1) is kept constant at 0.05~0.5 hours after each increase.

7. The method according to claim 1, characterized in that: The gelation reaction temperature in step (1) is 40-90℃, and the gelation reaction time is 0.3-5.0 hours.

8. The method according to claim 1, characterized in that: The organophosphorus source mentioned in step (1) is one or more of octadecyl ether phosphate, alkylphenol ether phosphate, isotridecyl ether phosphate, lauryl ether phosphate, castor oil phosphate, octadecyl phosphate, and lauryl phosphate; the molar ratio of the amount of the organophosphorus source added to Al in the aluminum salt solution in step (1) is 0.6:1 to 3.0:1; the organophosphorus source is divided into 2 to 8 parts by mass according to the number of pH increments.

9. The method according to claim 1, characterized in that: The sodium aluminate solution mentioned in step (2) has an Al weight concentration of 5 to 70 g / L, calculated as Al2O3; the sodium aluminate solution is divided into m parts by volume according to the number of additions, where m is an integer from 2 to 8.

10. The method according to claim 1, characterized in that: The aging temperature described in step (2) is 60 to 98°C for each aging process.

11. The method according to claim 1, characterized in that: The Al added via sodium aluminate solution is calculated as Al2O3, which is 5% to 55% of the Al in the catalyst.

12. The method according to claim 1, characterized in that: The drying conditions for step (3) are as follows: drying at 40~150℃ for 1~48 hours; adding one or more of the following during the molding process: the adhesive solvent is one or more of hydrochloric acid, nitric acid, sulfuric acid, acetic acid and oxalic acid; the extrusion aid is one or more of guar gum powder, carbon black, graphite powder and citric acid, and the amount of extrusion aid accounts for 1wt%~10wt% of the total dry basis of the material; the calcination conditions are as follows: calcining at 350~700℃ for 1~24 hours.

13. The method according to claim 1, characterized in that: The reduction in step (3) is carried out in a hydrogen atmosphere. In the first stage, the heating rate is 3~10℃ / min, from room temperature to 300~550℃, and the temperature is held for 1~5 hours. In the second stage, the temperature is raised to 600~750℃ at a heating rate of 0.5~5℃ / min, and the temperature is held for 2~8 hours. The heating rate in the second stage is more than 1℃ / min lower than the heating rate in the first stage. The hydrogen purity is greater than 99v%. The hydrogen flow rate is 150~700mL / min.

14. A special oil hydrocracking catalyst prepared by the method according to any one of claims 1 to 13, characterized in that: Based on the weight of the catalyst, the total content of transition metal phosphides is 15wt%~70wt%, β molecular sieve is 5wt%~20wt%, and amorphous alumina is 15wt%~65wt%; the transition metal phosphides are WP and Ni2P; wherein the weight ratio of Ni2P in the surface phase to the bulk phase is 2.6:1~7.0:1, the weight ratio of WP in the surface phase to the bulk phase is 2.3:1~6.3:1, and the Ni / W molar ratio is 0.1:1~14:

1.

15. The catalyst according to claim 14, characterized in that: The average particle diameter of transition metal phosphides is 2-6 nm.

16. The catalyst according to claim 14, characterized in that: Specific surface area is 150~700 m² 2 / g, pore volume is 0.25~1.2mL / g; pore size distribution is as follows: pores with diameter less than 6nm account for 3%~13% of the total pore volume, pores with diameter of 6~10nm account for 50%~73% of the total pore volume, pores with diameter of 10~15nm account for 8%~25% of the total pore volume, and pores with diameter greater than 15nm account for 7%~22% of the total pore volume.

17. The application of a special oil hydrocracking catalyst prepared by any one of claims 1 to 13 in the hydrocracking process for producing special oils.