A hydrofining catalyst and a method for preparing the same

Abstract

The application discloses a kind of hydrofining catalyst and preparation method thereof, including transition metal phosphide and alumina;The transition metal phosphide is WP and Ni2P;Wherein the weight content of Ni2P in surface phase and the weight content of Ni2P in bulk phase are 2.5:1~7.0:1, and the weight content of WP in surface phase and the weight content of WP in bulk phase are 2.5:1~6.5:1.Preparation method is as follows: (1) first gelation reaction is carried out to multiple metal solution and precipitator, and first slurry is obtained;(2) first slurry, nickel-containing solution and precipitator are added to the gelation tank containing bottom water and phosphate compound to carry out second gelation reaction, and second slurry is obtained;(3) second slurry is subjected to multiple pH value aging, and one portion of sodium metaaluminate solution is added in each aging process, and third slurry is obtained;(4) third slurry is filtered, dried and formed to prepare the hydrofining catalyst.The catalyst has large surface active site density, and is suitable for application in diesel fraction ultra-deep hydrodesulfurization and denitrification reaction.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of hydrogenation catalysts, and particularly relates to a phosphide hydrogenation refining catalyst with high transition metal content and a preparation method thereof. BACKGROUND

[0002] As a new type of hydrogenation catalyst, the phosphide catalyst has a minimum structural unit of triangular prism structure formed by metal atoms, and the triangular prism units form different lattice types in different combination modes, and the phosphorus atoms are arranged in the gaps inside the triangular prism. The phosphide has a structure of triangular prism unit, which is similar to a spherical shape, and the phosphide can expose more numbers of coordination unsaturated surface atoms than sulfides, thereby having a higher surface active site density. Factors affecting the activity of the phosphide mainly include: 1. The content of active metal, the more the active metal of the phosphide, the more the active centers can be provided. 2. The pore size and specific surface area of the phosphide catalyst affect its hydrogenation activity, and uneven dispersion of the active metal will cause disordered distribution of different hydrogenation active metals, and high content of metal in the bulk catalyst is prone to excessive accumulation of metal particles, thereby reducing the generation of active phase. 3. The co-precipitation method can prepare a precursor oxide with high content of active metal, but the content of surface phase metal is not high, thereby reducing the utilization rate of metal, and the phosphorization degree of the precursor oxide prepared by the method affects the activity of the phosphide. 4. The grain size and dispersion of the phosphide particles affect its activity.

[0003] CN101992109A discloses a transition metal phosphide hydrogenation refining catalyst and a preparation method thereof, and CN101168132A, CN1660695A, CN103962165A and CN102744089A adopt different methods to make the active metal more dispersedly distributed on the carrier during the preparation process. However, the transition metal phosphide obtained by the above method has a large grain size, the active metal is unevenly distributed, the content of the active metal is relatively small, and the hydrogenation activity is not obviously improved.

[0004] CN202010928225.9 provides a bulk phase nickel phosphide catalyst and a preparation method, a buffer system with a pH of 4-6 is prepared, a hypophosphite is added to the buffer system, and then a nickel salt or a mixed solution of the nickel salt and an auxiliary metal M precursor is slowly added, and reacted at 85-95℃ for 1-6h, and then filtered, washed and dried at 90-120℃ to obtain an amorphous precursor; the amorphous precursor is heat-treated in a hydrogen atmosphere, and then cooled to obtain a bulk phase nickel phosphide catalyst. The present application successfully prepares a Ni-P-based catalyst with Ni3P as the active phase by using a simple liquid-phase reduction method, but the pore volume and specific surface area of the catalyst are small.

[0005] CN111822015B discloses a preparation method of a hydrofining catalyst. The method comprises: (1) preparing mixed solution A containing transition metal and mixed solution B respectively; (2) mixing solution A and sodium metaaluminate alkaline solution and adding them into a reaction tank for gelation reaction to obtain slurry I, and aging; (3) mixing solution B and sodium metaaluminate alkaline solution and adding them into the aged slurry I for gelation reaction to obtain slurry II, adding an organic phosphorus compound, and aging; (4) drying, shaping and calcining the obtained material to obtain a phosphide catalyst precursor; and (5) reducing the obtained material by hydrogen program temperature to obtain a hydrofining catalyst. The catalyst prepared by the method has small phosphide particle size, more active centers and good dispersion, but the surface phase metal content is small, the phosphorization degree is low, and the hydrogenation activity needs to be further improved.

[0006] At present, the number of active centers of the phosphide catalyst prepared by the coprecipitation method can be greatly increased. Compared with the supported phosphide catalyst, although the phosphide catalyst prepared by the coprecipitation method has high active metal content, the pore volume and specific surface area are small, the phosphide particle size is uneven, the active metal content in the surface phase of the catalyst is low, and the utilization rate of the active metal is affected. Therefore, how to improve the pore volume and specific surface area of the phosphide catalyst prepared by the coprecipitation method, increase the active metal content in the surface phase of the catalyst, and improve the utilization rate of the phosphide are the main problems faced by the preparation of the phosphide catalyst by the coprecipitation method. SUMMARY

[0007] In view of the deficiencies of the prior art, the present application provides a hydrofining catalyst and a preparation method thereof. The catalyst is a phosphide hydrofining catalyst with high transition metal content, high surface phase active site density, more active centers, small phosphide grain size, high hydrodesulfurization and hydrodenitrogenation reaction performance, and is suitable for application in diesel fraction ultra-deep hydrodesulfurization and denitrogenation reactions.

[0008] The hydrofining catalyst of the present application comprises transition metal phosphide and alumina. The total content of the transition metal phosphide is 35% to 82%, preferably 38% to 78%, and the content of the alumina is 18% to 65%, preferably 22% to 62%, based on the weight of the catalyst. The transition metal phosphide is WP and Ni2P. The ratio of the weight content of Ni2P in the surface phase to the weight content of Ni2P in the bulk phase is 2.5:1 to 7.0:1, preferably 3.0:1 to 6.5:1, and the ratio of the weight content of WP in the surface phase to the weight content of WP in the bulk phase is 2.5:1 to 6.5:1, preferably 3.0:1 to 6.0:1.

[0009] The molar ratio of Ni / W is 0.1:1 to 12:1, preferably 0.3:1 to 10:1.

[0010] The average diameter of the transition metal phosphide particles is 2-7 nm, preferably 3-6 nm.

[0011] 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 2-10% of the total pore volume, the pore volume of the pores with a diameter of 6-10 nm accounts for 45-67% of the total pore volume, the pore volume of the pores with a diameter of 10-15 nm accounts for 12-35% of the total pore volume, and the pore volume of the pores with a diameter of 15 nm or more accounts for 10-28% of the total pore volume.

[0012] The preparation method of the hydrofining catalyst of the present application comprises the following steps:

[0013] (1) The multi-metal solution and the first precipitant are added into a gelation tank containing bottom water to perform a first gelation reaction to obtain a first slurry; the multi-metal solution is a solution containing W, Ni and Al; the first precipitant is ammonia water and a sodium phosphate solution;

[0014] (2) The first slurry, a nickel-containing solution and the second precipitant are added into a gelation tank containing bottom water and a phosphate ester compound to perform a second gelation reaction to obtain a second slurry; the second precipitant is ammonia water and a sodium phosphate solution;

[0015] (3) The second slurry is subjected to multiple pH value changing aging processes, and a portion of sodium metaaluminate solution is added in each aging process to obtain a third slurry;

[0016] (4) The third slurry is filtered, dried, shaped, washed, dried again, calcined to obtain a phosphide catalyst precursor, and then reduced by hydrogen to obtain a hydrofining catalyst.

[0017] In the method of the present application, the concentration of the ammonia water in the first precipitant and the second precipitant in step (1) and step (2) is 5wt%-10wt%, the concentration of the sodium phosphate solution is 8wt%-20wt%, and the molar ratio of the ammonia water (calculated as NH3) to the sodium phosphate is 0.2:1-0.6:1. The molar ratio of the ammonia water to the sodium phosphate in step (1) and step (2) can be the same or different, and is preferably the same.

[0018] In the method of the present application, the weight concentration of W (calculated as WO3) in the multi-metal solution in step (1) is 5-140g / L, preferably 10-130g / L, the weight concentration of Ni (calculated as NiO) is 5-110g / L, preferably 8-105g / L, and the weight concentration of Al (calculated as Al2O3) is 2-90g / L, preferably 6-85g / L. When the solution containing W, Ni and Al is prepared, the commonly used tungsten source is ammonium metatungstate, the commonly used nickel source is one or more of nickel sulfate, nickel nitrate and nickel chloride, and the commonly used aluminum source is one or more of aluminum nitrate, aluminum sulfate, aluminum chloride and aluminum acetate.

[0019] In the method, the first gelation reaction in step (1) is carried out at a temperature of 30-95°C, preferably 40-95°C, and a pH of 5-6, and the reaction time is 0.1-1.0 hour.

[0020] In the method, the nickel-containing solution in step (2) has a concentration of Ni (calculated as NiO) of 10-130 g / L, preferably 15-115 g / L; and the nickel source is generally one or more of nickel sulfate, nickel nitrate and nickel chloride.

[0021] In the method, the phosphoric acid ester compound in step (2) is one or more of octadecyl ether phosphoric acid ester (O-5P), alkyl phenol ether phosphoric acid ester (TXP-4, TXP-10), isomeric tridecanol ether phosphoric acid ester (E-1310P), lauryl alcohol ether phosphoric acid ester (MOA-3P, MOA-9P), castor oil phosphoric acid ester, octadecyl phosphoric acid ester and lauryl phosphoric acid ester, preferably one or more of alkyl phenol ether phosphoric acid ester (TXP-4, TXP-10), isomeric tridecanol ether phosphoric acid ester (E-1310P), lauryl alcohol ether phosphoric acid ester (MOA-3P, MOA-9P), octadecyl phosphoric acid ester and castor oil phosphoric acid ester. The amount of the phosphoric acid ester compound added is in a molar ratio of 0.8:1-6.0:1, preferably 1.5:1-5.5:1, to the Ni in the nickel-containing solution.

[0022] In the method, the second gelation reaction in step (2) is carried out at a temperature of 30-95°C, preferably 40-95°C, and a pH of 8.0-10.5, and the reaction time is 0.5-2.5 hours; preferably, the temperature of the reaction in step (2) is the same as that in step (1).

[0023] In the method, the multiple pH adjustment aging process in step (3) comprises the following steps: first, adjusting the pH of the second reaction slurry to 11.5-13.5 by adding a sodium metaaluminate solution, and aging for 0.05-0.5 hours; second, adjusting the pH to 8.5-10.5, and aging for 0.05-0.5 hours; third, adjusting the pH to 4.5-6.3, and aging for 0.05-0.5 hours; and repeating the above three steps for 2-8 times. The aging temperature is 60-98°C, preferably 65-92°C. In the aging process, the sodium metaaluminate solution is used in the first step, and the acid and base used in the adjustment of the pH in the other steps can be inorganic salts, inorganic acids and inorganic bases not containing aluminum, the inorganic acid can be hydrochloric acid and acetic acid, and the inorganic base can be one or more of sodium carbonate, sodium bicarbonate, ammonia and sodium hydroxide. The concentration and amount of the acid and base solution can be adjusted according to the actual needs.

[0024] In the method of the present application, the weight concentration of Al, calculated as Al2O3, in the sodium metaaluminate solution in step (3) is 5-70 g / L, preferably 8-60 g / L. The sodium metaaluminate solution is aliquoted by volume, and the number of aliquots is the number of times of aging.

[0025] In the method of the present application, the Ni added through the Ni-containing solution accounts for 55-85%, preferably 60-82%, of the total Ni, calculated as NiO, in the obtained hydrofining catalyst.

[0026] In the method of the present application, the Al added through the sodium metaaluminate solution accounts for 5-55%, preferably 6-50%, of the total Al, calculated as Al2O3, in the obtained hydrofining catalyst.

[0027] In the method of the present application, the drying, shaping and washing in step (4) can be carried out by conventional methods in the art. The drying conditions are as follows: drying at 40-150°C for 1-48 hours, preferably 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., and the extrusion aid is one or more of substances that are beneficial to extrusion shaping, such as amaranth powder, 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 using deionized water or a solution containing decomposable salts (such as ammonium acetate, ammonium chloride, ammonium nitrate, etc.) until neutral.

[0028] In the method of the present application, the calcination conditions in step (4) are as follows: the calcination temperature is 350-700°C, and the calcination time is 1-24 hours.

[0029] In the method of the present application, the hydrogen reduction in step (4) is carried out by temperature programmed reduction, and the specific process includes: the precursor is under a hydrogen atmosphere with a hydrogen purity of greater than 99 v%, and the hydrogen flow rate is 150-700 mL / min, preferably 250-600 mL / min; 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 held 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 held constant for 2-8 hours; the temperature raising rate in the second stage is at least 1°C / min lower than that in the first stage, preferably at least 2°C / min lower. To prevent the phosphide from undergoing a violent oxidation reaction upon contact 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 being exposed to air.

[0030] The hydrogen refining catalyst of the present application can be in the shape of a sheet, a sphere, a cylindrical strip, and a special-shaped strip (three-leaf clover, four-leaf clover) as needed, preferably a cylindrical strip and a special-shaped strip (three-leaf clover, four-leaf clover). The diameter of the catalyst can be a fine strip of 0.8-2.0 mm and a thick strip of >2.5 mm.

[0031] The hydrogen refining catalyst of the present application is used in the ultra-deep hydrodesulfurization, denitrification reaction, 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.

[0032] The catalyst surface phase of the bulk catalyst of the present application has a high hydrogenation active site, and the utilization rate of the active metal is high, thereby improving the hydrogenation activity for treating heavy oil, reducing the catalyst preparation cost, and being particularly beneficial to the saturation of aromatic hydrocarbons in heavy oil, effectively reducing the content of polycyclic aromatic hydrocarbons, and improving the cetane number. Compared with the prior art, the specific advantages are as follows:

[0033] 1. In the present application, phosphate ester and sodium phosphate are used as phosphorus sources, wherein sodium phosphate and ammonia water are used as a precipitant in a specific ratio, the generated reactants have a uniform distribution of phosphorus, and the addition of phosphate ester in the second gelation reaction process makes the phosphorus uniformly distributed on the catalyst surface, and improves the strong interaction between W, Ni, P and the carrier, so that the transition active metal is fully phosphatized, and the phosphide is prevented from gathering on the catalyst surface.

[0034] 2. In the present application, the W, Ni, Al-containing solution is first precipitated, and the Ni-containing solution is added dropwise in the obtained slurry at a specific pH value. The specific addition sequence, the corresponding pH value control, and the active metal precipitation sequence significantly increase the content of the active metal in the surface phase.

[0035] 3. In the present application, the amorphous oxide in the oxide particles is dissolved through multiple pH value aging processes, the size of the oxide particles is modified again by adding sodium metaaluminate solution, the growth of the oxide particles is controlled through n times of pH value swing, the oxide particles are more uniform and small, more active metals are exposed to the surface phase, the macropores in the bulk catalyst can be increased, the macromolecular reactants can easily pass through the pores, at the same time, the aluminum introduced by the sodium metaaluminate solution increases the surface hydroxyl group, further enhances the adhesion of the oxide, and is beneficial to the molding of the bulk catalyst. DETAILED DESCRIPTION

[0036] In the present application, the specific surface area, pore volume, and pore distribution are determined by a low-temperature liquid nitrogen adsorption method, the mechanical strength is determined by a side pressure method, and the diameter of the transition metal phosphide particles is determined by a TEM technology. In the present application, wt% is a mass fraction, and v% is a volume fraction.

[0037] The catalyst surface phosphide content is determined by X-ray photoelectron spectroscopy (XPS), and the catalyst bulk phosphide content is determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES). First, the surface and bulk active metal contents of the transition metal oxide precursor of the catalyst are determined, and then the transition metal phosphide contents in the surface and bulk of the catalyst are converted. Example 1

[0038] Ammonium metatungstate, nickel chloride, and aluminum chloride solution were added to a dissolving tank 1 containing deionized water to prepare a W, Ni, and Al-containing solution. The W, Ni, and Al-containing solution had a W concentration of 40 g / L as WO3, a Ni concentration of 28 g / L as NiO, and an Al concentration of 56 g / L as Al2O3. Nickel chloride was added to a dissolving tank 2 containing deionized water to prepare a Ni-containing solution. The Ni in the Ni-containing solution accounted for 65% of the total Ni in the obtained hydrofining catalyst as NiO. The Al in the sodium metaaluminate solution accounted for 30% of the total Al in the obtained hydrofining catalyst as Al2O3. The solution was divided into four equal parts by volume. Deionized water was added to a reaction tank 1. Ammonia, sodium phosphate solution, and the W, Ni, and Al-containing solution were added to the reaction tank to perform a gelation reaction. The molar ratio of ammonia to sodium phosphate in the ammonia and sodium phosphate solution was 0.4:1. The gelation temperature was maintained at 60°C. The pH value during the concurrent gelation reaction was controlled at 5.2. The gelation time was controlled at 0.7 hours. A precipitate slurry I containing W, Al, Ni, and P was generated. Deionized water and castor oil phosphate were added to a reaction tank 2. The molar ratio of castor oil phosphate to the total number of Ni atoms in the Ni-containing solution was 2.6. The W, Al, Ni, and P-containing slurry I, the Ni-containing solution, and the ammonia and sodium phosphate solution were added to the reaction tank 2 in a concurrent manner (the molar ratio of ammonia to sodium phosphate in the ammonia and sodium phosphate solution was 0.4:1). The reaction temperature was unchanged. The reaction time was 1.0 hour. The reaction pH value was controlled at 8.9. A precipitate slurry containing Ni, W, Al, and P was generated. The obtained slurry was aged. The aging temperature was 76°C. During the aging, the first part of the sodium metaaluminate solution was added. The pH value was controlled at 13.3. The aging time was 0.2 hours. Then, the aging pH value was controlled at 9.7. The aging time was 0.2 hours. Subsequently, the pH value was controlled at 5.5. The aging time was 0.15 hours. The above operation was repeated four times. The aging was completed. The aged slurry was filtered. The filter cake was dried at 100°C for 8 hours. The filter cake was rolled and extruded into a strip. The wet strip was washed with deionized water until neutral at room temperature. Then, the washed wet strip was dried at 80°C for 10.0 hours. The dried material was calcined at 530°C for 5 hours to obtain a phosphide catalyst precursor A. The precursor A was heated to 410°C at a hydrogen flow rate of 290 mL / min and a temperature increase rate of 6°C / min under a pure hydrogen atmosphere. After being kept at 410°C for 3.6 hours, the temperature was increased to 710°C at a temperature increase rate of 2.5°C / min. The temperature was kept at 710°C for 4 hours. To prevent the phosphide from undergoing a severe oxidation reaction with air, the catalyst sample was passivated with a 2% O2 / N2 passivation gas for 2 hours before being exposed to air. A hydrofining catalyst A was obtained. The catalyst composition and main physicochemical properties are shown in Table 1. Example 2

[0039] Ammonium metatungstate, nickel chloride, and aluminum chloride solution were added to 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 was 46 g / L as WO3, the weight concentration of Ni was 25.9 g / L as NiO, and the weight concentration of Al was 54.6 g / L as Al2O3. Nickel chloride was added to a dissolving tank 2 containing deionized water to prepare a solution containing Ni. The Ni in the solution containing Ni accounted for 63% of the total Ni in the obtained hydrofining catalyst as NiO. The Al in the sodium metaaluminate solution accounted for 35% of the total Al in the obtained hydrofining catalyst as Al2O3. The solution containing W, Ni, and Al was divided into five equal parts by volume. Deionized water was added to a reaction tank 1. Ammonia, sodium phosphate solution, and the solution containing W, Ni, and Al were added to the reaction tank to perform a gelation reaction. The molar ratio of ammonia to sodium phosphate in the ammonia and sodium phosphate solution was 0.35:1. The gelation temperature was maintained at 65°C. The pH value during the concurrent gelation reaction was controlled at 5.5. The gelation time was controlled at 0.8 hours. A precipitate slurry I containing W, Al, Ni, and P was generated. Deionized water and lauryl ether phosphate were added to a reaction tank 2. The molar ratio of lauryl ether phosphate to the total number of Ni atoms in the solution containing Ni was 2.3. The slurry I containing W, Al, Ni, and P, the solution containing Ni, and the ammonia and sodium phosphate solution were added to the reaction tank 2 in a concurrent manner (the molar ratio of ammonia to sodium phosphate in the ammonia and sodium phosphate solution was 0.35:1). The reaction temperature was unchanged. The reaction time was 1.2 hours. The reaction pH value was controlled at 9.3. A precipitate slurry containing Ni, W, Al, and P was generated. The obtained slurry was aged. The aging temperature was 80°C. During the aging, the first part of the sodium metaaluminate solution was added. The pH value was controlled at 13.0. The aging time was 0.15 hours. After that, the aging pH value was controlled at 9.4. The aging time was 0.2 hours. Then, the pH value was controlled at 5.1. The aging time was 0.15 hours. The above operation was repeated five times. The aging was completed. The aged slurry was filtered. The filter cake was dried at 90°C for 9 hours. The filter cake was rolled and 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 80°C for 9.0 hours. The dried material was calcined at 540°C for 4 hours to obtain a phosphide catalyst precursor B. The precursor B was heated in a pure hydrogen atmosphere. The hydrogen flow rate was 320 mL / min. The heating rate was 5°C / min. The temperature was increased from room temperature to 415°C. The temperature was kept constant for 3.4 hours. Then, the temperature was increased to 680°C at a heating rate of 3.0°C / min. The temperature was kept constant 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 2.2% for 3 hours before the catalyst sample was exposed to air. A hydrofining catalyst B was obtained. The catalyst composition and main physicochemical properties are shown in Table 1. Example 3

[0040] Ammonium metatungstate, nickel chloride, and aluminum chloride solution were added to a dissolving tank 1 containing deionized water to prepare a W, Ni, and Al-containing solution. The W, Ni, and Al-containing solution had a W concentration of 30 g / L as WO3, a Ni concentration of 26.4 g / L as NiO, and an Al concentration of 60.7 g / L as Al2O3. Nickel chloride was added to a dissolving tank 2 containing deionized water to prepare a Ni-containing solution. The Ni in the Ni-containing solution accounted for 70% of the total Ni in the obtained hydrofining catalyst as NiO. The Al in the sodium metaaluminate solution accounted for 26% of the total Al in the obtained hydrofining catalyst as Al2O3. The solution was divided into six equal parts by volume. Deionized water was added to a reaction tank 1. Ammonia, sodium phosphate solution, and the W, Ni, and Al-containing solution were concurrently added to the reaction tank to perform a gelation reaction. The molar ratio of ammonia to sodium phosphate in the ammonia and sodium phosphate solution was 0.42:1. The gelation temperature was maintained at 55°C. The pH value during the concurrent gelation reaction was controlled at 5.7. The gelation time was controlled at 0.7 hours. A precipitate slurry I containing W, Al, Ni, and P was generated. Deionized water and isomeric tridecanol ether phosphate were added to a reaction tank 2. The molar ratio of isomeric tridecanol ether phosphate to the total number of Ni atoms in the Ni-containing solution was 3.2. The precipitate slurry I containing W, Al, Ni, and P, the Ni-containing solution, and the ammonia and sodium phosphate solution were concurrently added to the reaction tank 2 (the molar ratio of ammonia to sodium phosphate in the ammonia and sodium phosphate solution was 0.42:1). The reaction temperature was unchanged. The reaction time was 1.3 hours. The reaction pH value was controlled at 8.7. A precipitate slurry containing Ni, W, Al, and P was generated. The obtained slurry was aged. The aging temperature was 83°C. During the aging, one part of the sodium metaaluminate solution was first added. The pH value was controlled at 12.7. The aging time was 0.2 hours. Then, the aging pH value was controlled at 9.9. The aging time was 0.15 hours. Subsequently, the pH value was controlled at 4.6. The aging time was 0.2 hours. The above operation was repeated six times. The aging was completed. The aged slurry was filtered. The filter cake was dried at 120°C for 8 hours. The filter cake was rolled and extruded into a strip. The wet strip was washed with deionized water until neutral at room temperature. Then, the washed wet strip was dried at 90°C for 10.0 hours. The dried material was calcined at 510°C for 6 hours to obtain a phosphide catalyst precursor C. The precursor C was heated in a pure hydrogen atmosphere. The hydrogen flow rate was 350 mL / min. The heating rate was 7°C / min. The temperature was increased from room temperature to 440°C. The temperature was kept constant for 2.9 hours. The temperature was increased to 660°C at a heating rate of 4.0°C / min. The temperature was kept constant for 6 hours. To prevent the phosphide from reacting violently with air due to oxidation, the catalyst sample was passivated with an O2 / N2 passivation gas with an oxygen volume concentration of 2.3% for 3.2 hours before the catalyst sample was exposed to air. A hydrofining catalyst C was obtained. The catalyst composition and main physicochemical properties are shown in Table 1. Example 4

[0041] Ammonium metatungstate, nickel chloride, and aluminum chloride solution were added to a dissolving tank 1 containing deionized water to prepare a W, Ni, and Al-containing solution, and the W, Ni, and Al-containing solution had a W concentration of 24 g / L as WO3, a Ni concentration of 23 g / L as NiO, and an Al concentration of 52 g / L as Al2O3. Nickel chloride was added to a dissolving tank 2 containing deionized water to prepare a Ni-containing solution, and the Ni in the Ni-containing solution accounted for 75% of the total Ni in the obtained hydrofining catalyst as NiO. The Al in the sodium metaaluminate solution accounted for 38% of the total Al in the obtained hydrofining catalyst as Al2O3, and the sodium metaaluminate solution was divided into five equal parts by volume. Deionized water was added to a reaction tank 1, and ammonia water, sodium phosphate solution, and the W, Ni, and Al-containing solution were added to the reaction tank to perform a gelation reaction, the molar ratio of ammonia to sodium phosphate in the ammonia water and sodium phosphate solution was 0.5:1, the gelation temperature was maintained at 68°C, the pH value during the concurrent gelation reaction was controlled at 5.5, the gelation time was controlled at 0.6 hours, and a precipitate slurry I containing W, Al, Ni, and P was generated. Deionized water and castor oil phosphate were added to a reaction tank 2, and the molar ratio of castor oil phosphate to the total number of Ni atoms in the Ni-containing solution was 2.2. The W, Al, Ni, and P-containing slurry I, the Ni-containing solution, and the ammonia water and sodium phosphate solution were added to the reaction tank 2 in a concurrent manner (the molar ratio of ammonia to sodium phosphate in the ammonia water and sodium phosphate solution was 0.5:1), the reaction temperature was not changed, the reaction time was 1.1 hours, the reaction pH value was controlled at 9.5, and a precipitate slurry containing Ni, W, Al, and P was generated. The obtained slurry was aged, the aging temperature was 87°C, and during the aging, a first part of the sodium metaaluminate solution was added first, the pH value was controlled at 12.9, the aging time was 0.15 hours, then the aging pH value was controlled at 9.1, the aging time was 0.2 hours, then the pH value was controlled at 5.0, the aging time was 0.15 hours, and the above-mentioned operation was repeated five times, 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 wet strip after washing was washed with deionized water until neutral at room temperature. Then the washed wet strip was dried at 90°C for 11.0 hours. The dried material was calcined at 530°C for 5 hours to obtain a phosphide catalyst precursor D. The precursor D was heated in a pure hydrogen atmosphere, the hydrogen flow rate was 400 mL / min, the heating rate was 7 ℃ / min, the temperature was increased from room temperature to 450 ℃, the temperature was kept constant for 4.0 hours, then the temperature was increased to 680 ℃ at a heating rate of 3.5 ℃ / 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 1.8% for 3.5 hours before the catalyst sample was exposed to air to obtain a hydrofining catalyst D. The catalyst composition and main physicochemical properties are shown in Table 1.

[0042] Comparative Example 1

[0043] According to the preparation method of Example 3 disclosed in CN111822015A, reference agent G, the specific process is as follows:

[0044] According to the component content ratio of catalyst C in Table 1, nickel nitrate and ammonium metatungstate were added to the dissolving tank 1 to prepare a mixed solution A, the weight concentration of Ni in the mixed solution A was 23.4 g / L as calculated by NiO, and the weight concentration of W was 20 g / L as calculated by WO3. Nickel nitrate was added to the dissolving tank 2 to prepare a mixed solution B, the weight concentration of Ni in the mixed solution B was 28 g / L as calculated by NiO. Tetrapropyl ammonium bromide and deionized water were added to the reaction tank, the total molar ratio of tetrapropyl ammonium bromide to tungsten and nickel in the mixed solution A was 1.5:1, a sodium metaaluminate solution with a weight concentration of 30 g / L as calculated by Al2O3 was added to the reaction tank in parallel with the mixed solution A, the coagulation temperature was maintained at 53°C, the pH value was controlled at 7.5 during the parallel coagulation reaction process, the coagulation time was controlled at 1.3 hours, and a precipitate slurry I was generated. The obtained precipitate slurry I was aged under stirring, the stirring speed was 215 r / min, the aging temperature was 72°C, the aging pH value was controlled at 7.1, and the aging time was 0.4 hours. After the aging was completed, the solution B, phenylethylamine, and a sodium metaaluminate solution with a weight concentration of 24 g / L as calculated by Al2O3 were added to the slurry I in parallel, the molar ratio of phenylethylamine to nickel in the mixed solution B was 1.3:1, the coagulation temperature was maintained at 52°C, the pH value was controlled at 8.7 during the parallel coagulation reaction process, and the coagulation time was controlled at 2.7 hours, and a precipitate slurry II was obtained. Hexanediamine tetramethylene phosphonic acid was added to the precipitate slurry II, the molar ratio of hexanediamine tetramethylene phosphonic acid to transition metals in the finally prepared hydrofining catalyst was 4.0:1, the stirring speed was 380 r / min, the aging temperature was 75°C, the pH value was controlled at 9.1, and the aging time was 4.6 hours, and the obtained material was dried at 160°C for 10 hours, was rolled, was extruded into a strip, and was formed. After the forming, the phosphide catalyst precursor C was obtained by calcining at 490°C for 6 hours. The precursor C was heated to 510°C at a heating rate of 5.8°C / min from room temperature under a hydrogen atmosphere, was kept at 510°C for 5 hours, was heated to 710°C at a heating rate of 3.2°C / min, and was kept at 710°C for 6 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 1.1% for 4 hours before the catalyst sample contacted with air, and the hydrofining catalyst E was obtained. In the hydrofining catalyst E, the weight of nickel and tungsten introduced by the mixed solution A accounted for 55% of the weight of nickel and tungsten in the hydrofining catalyst E, and the weight of Al in the precipitate I accounted for 62% of the weight of Al in the hydrofining catalyst E. The catalyst composition and main physicochemical properties are shown in Table 1.

[0045] Comparative Example 2

[0046] The same as Example 1, Reference F was prepared, but no aluminum was added during aging, and was added during the first gelation reaction. The aging pH value was fixed. The preparation process was as follows:

[0047] Ammonium metatungstate, nickel chloride, and aluminum chloride solution were added to a dissolving tank 1 containing deionized water to prepare a W, Ni, and Al-containing solution. The W, Ni, and Al-containing solution had a W concentration of 40 g / L as WO3, a Ni concentration of 28 g / L as NiO, and an Al concentration of 80 g / L as Al2O3. Nickel chloride was added to a dissolving tank 2 containing deionized water to prepare a Ni-containing solution. The Ni in the Ni-containing solution accounted for 65% of the total Ni in the obtained hydrofining catalyst as NiO. Deionized water was added to a reaction tank 1, and ammonia water, sodium phosphate solution, and the W, Ni, and Al-containing solution were added to the reaction tank to perform a gelation reaction. The molar ratio of ammonia to sodium phosphate in the ammonia water and sodium phosphate solution was 0.4:1. The gelation temperature was maintained at 60°C. The pH value during the concurrent gelation reaction was controlled at 5.2. The gelation time was controlled at 0.7 hours. A W, Al, Ni, and P-containing precipitate slurry I was generated. Deionized water and castor oil phosphate were added to a reaction tank 2. The molar ratio of castor oil phosphate to the total number of Ni atoms in the Ni-containing solution was 2.6. The W, Al, Ni, and P-containing slurry I, the Ni-containing solution, and the ammonia water and sodium phosphate solution were added to the reaction tank 2 in a concurrent manner (the molar ratio of ammonia to sodium phosphate in the ammonia water and sodium phosphate solution was 0.4:1). The reaction temperature was unchanged. The reaction time was 1.0 hour. The reaction pH value was controlled at 8.9. A precipitate slurry containing Ni, W, Al, and P was generated. The obtained slurry was aged. The aging temperature was 76°C. The aging pH value was controlled at 8.5. The aging time was 2.5 hours. The aging was ended. The aged slurry was filtered. The filter cake was dried at 100°C for 8 hours. The filter cake was rolled and 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 80°C for 10.0 hours. The dried material was calcined at 530°C for 5 hours to obtain a phosphide catalyst precursor F. The precursor F was heated in a pure hydrogen atmosphere. The hydrogen flow rate was 290 mL / min. The heating rate was 6 ℃ / min. The temperature was increased from room temperature to 410°C. The temperature was kept constant for 3.6 hours. The temperature was increased to 710°C at a heating rate of 2.5 ℃ / min. The temperature was kept constant for 4 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 2 hours before being exposed to air. A hydrofining catalyst F was obtained. The catalyst composition and main physicochemical properties are shown in Table 1.

[0048] Comparative Example 3

[0049] The same as Example 1, Reference G was prepared using ammonia water as a precipitant.

[0050] Comparative Example 4

[0051] Example 1, using sodium phosphate solution as precipitant to prepare Reference Agent H.

[0052] Comparative Example 5

[0053] Example 1, using the molar ratio of ammonia (as NH3) to sodium phosphate of 0.75:1 to prepare Reference Agent I. Example 5

[0054] This example is an evaluation experiment of the catalyst activity of the present application, and is compared with the catalysts of the comparative examples. The catalysts of the present application A, B, C and D and the catalysts of the comparative examples E, F, G, H and I are respectively used to carry out comparative evaluation experiments in a 200 mL small hydrogenation device. The experimental process is as follows: 60 mL of hydrogenation refining catalyst is uniformly mixed with 340 mL of quartz sand and then loaded into a small fixed bed reactor. The catalyst is purged with hydrogen before reaction, heated to 660℃ at a rate of 10℃ / min and kept for 40 min to remove the surface passivation layer to obtain fresh hydrogenation refining catalyst. The catalyst activity evaluation process conditions are: hydrogen partial pressure is 6.4 MPa, reaction temperature is 358℃, liquid hourly space velocity is 1.8 h -1 - 1 -1 , hydrogen to oil volume ratio is 500:1, and the evaluation results are shown in Table 4. The types of nitrogen compounds in the hydrogenation refined oil are detected by gas chromatography-atomic emission spectrometry detector (GC-AED), and the results are shown in Table 5.

[0055] From the physical and chemical properties and evaluation results of the phosphide catalyst, it can be seen that the catalyst of the present application has excellent hydrogenation activity. The phosphide particles in the catalyst are small, the content of phosphide in the catalyst surface phase is high, and the phosphide is uniformly dispersed. The catalyst not only has excellent hydrogenation desulfurization activity and hydrogenation denitrification activity, but also has excellent hydrogenation saturation performance, effectively reduces the content of aromatic hydrocarbons in heavy distillate oil, and the content of polycyclic aromatic hydrocarbons is reduced more obviously. Compared with Reference Agent E, the mass content of active metal oxides is reduced by 11 m%. The catalyst of the present application is used for processing heavy distillate oil, especially for processing poor quality diesel oil fraction with high aromatic hydrocarbon content and difficult to process. The catalyst has excellent hydrogenation saturation, hydrogenation desulfurization and hydrogenation denitrification performance, effectively reduces the content of polycyclic aromatic hydrocarbons, and improves the cetane number of diesel oil.

[0056] Table 1 Catalyst composition and properties prepared in examples and comparative examples

[0057] Catalyst No. A B C D E F G H I [Ni2P, wt%] 40 35 44 46 53 40 40 40 40 WP, wt% 20 23 15 12 18 20 20 20 20 Al203, wt% balance balance balance balance balance balance balance balance balance Specific surface area, m 2 / g]] 307 301 312 317 273 258 156 299 178 balance 0.431 0.420 0.439 0.445 0.383 0.354 0.221 0.419 0.289 Pore volume, mL / g Pore distribution, % 5.32 5.63 5.03 4.89 35.67 47.13 70.36 6.45 57.31 < 6 nm 55.61 55.42 57.11 57.02 16.85 32.45 16.45 40.12 20.23 6 nm - 10 nm 20.87 20.74 18.67 18.46 37.68 11.25 8.35 32.46 10.15 10 nm - 15 nm 18.20 18.21 19.19 19.63 9.80 9.17 5.84 20.97 12.31 > 15 nm 4.3 4.2 4.5 4.4 5.3 8.1 7.8 22.1 11.9

[0058] Table 2 Ratio of weight content of active metal oxides in catalyst surface phase to weight content of active metal oxides in catalyst bulk phase

[0059] Average diameter of transition metal phosphide particles, nm A B C D E F G H I Table phase I Ni2P Bulk phase I Ni2P ]]> 5.64 5.45 5.78 5.89 1.22 2.04 1.64 2.14 1.85 Table phase I WP Bulk phase I WP ]]> 4.78 4.63 4.88 4.96 1.13 1.35 1.22 1.42 1.31

[0060] Table 3 Main properties of raw oil

[0061] Catalyst No. Item Density (20°C), g / cm 3 ]] 0.9393 Analysis result 162-384 Distillation range, °C 14980 S, pg / g 898 N, pg / g 72.6 Aromatics, wt% 46.8 Polycyclic aromatics, wt% ＜24

[0062] Table 4 Catalyst activity evaluation results

[0063] Cetane number A B C D E F Density of the produced oil (20°C), g / cm 3 ]] 0.8674 0.8678 0.8672 0.8670 0.8682 0.8768 Catalyst No. 168-368 167-369 167-367 166-366 172-371 180-376 Distillation range, °C 7.5 8.2 7.0 6.9 9.8 74.3 S, pg / g 4.8 4.2 4.4 4.1 8.5 45.4 N, pg / g 34.7 35.1 34.4 34.0 38.8 46.5 Aromatics, wt% 5.0 5.4 4.8 4.6 7.5 16.1 Polycyclic aromatics, wt% 39.1 38.9 39.5 39.8 38.4 30.5

[0064] Table 4 (continued)

[0065] Cetane number G H I Density of the produced oil (20°C), g / cm 3 ]]> 0.8813 0.8784 0.8801 Catalyst No. 184-379 182-377 185-378 Distillation range, °C 130.2 98.4 110.7 S, pg / g 77.6 60.8 68.6 N, pg / g 56.3 51.6 53.8 Aromatics, wt% 23.4 19.4 21.8 Polycyclic aromatics, wt% 26.1 29.3 27.8

[0066] Table 5 Content of different nitrogen compounds in hydrofinished oil

[0067] Cetane number A B C D E F G H I Catalyst No. 4.8 4.2 4.4 4.1 8.5 45.4 77.6 60.8 68.6 Nitrogen content in hydrofinished oil, pg / g 2.6 2.4 2.5 2.3 4.5 21.8 38.9 31.2 34.3 1-MCB, pg / g 1.2 1.1 1.1 1.1 2.5 15.4 23.3 18.4 21.1 1,8-BMCB, pg / g 1,4,8-TMCB, pg / g 1,2,4,8-TMCB, pg / g 1,2,4,8-TMCB, pg / g 1,2,4,8-TMCB, pg / g 1,2,4,8-TMCB, pg / g 1,2,4,8-TMCB, pg / g 1,2,4,8-TMCB, pg / g 1,2,4,8-TMCB, pg / g 1,2,4,8-TMCB, pg / g 1,2,4,8-TMCB, pg / g 1,2,4,8-TMCB, pg / g 1,2,4,8-TMCB, pg / g 1,2,4,8-TMCB, pg / g 1,2,4,8-TMCB, pg / g 1,2,4,8-TMCB, pg / g 1,2,4,8-TMCB, pg / g 1,2,4,8-TMCB, pg / g 1,2,4,8-TMCB, pg / g 1,2,4,8-TMCB, pg / g 1,2,4,8-TMCB, pg / g 1,2,4,8-TMCB, pg / g 1,2,4,8-TMCB, pg / g 1,2 1.0 0.7 0.8 0.7 1.5 8.2 15.4 11.2 13.2

Claims

1. A method for preparing a hydrorefining catalyst, characterized in that... The process includes the following steps: (1) A multi-metal solution and a first precipitant are added concurrently to a gelling tank containing bottom water to perform a first gelling reaction, resulting in a first slurry; the multi-metal solution is a solution containing W, Ni, and Al; the first precipitant is ammonia and sodium phosphate solution; (2) The first slurry, a nickel-containing solution, and a second precipitant are added concurrently to a gelling tank containing bottom water and phosphate ester compounds to perform a second gelling reaction, resulting in a second slurry; the second precipitant is ammonia and sodium phosphate solution; (3) The second slurry undergoes multiple pH-adjusted aging processes, with a portion of sodium aluminate solution added during each aging process to obtain a third slurry; (4) The third slurry is filtered, dried, shaped, washed, and then dried and calcined to obtain a phosphide catalyst precursor, which is then reduced with hydrogen to obtain a hydrogenation refining catalyst; the first and second precipitants mentioned in steps (1) and (2) are... The concentration of ammonia water is 5wt% to 10wt%, the concentration of sodium phosphate solution is 8wt% to 20wt%, and the molar ratio of ammonia water (calculated as NH3) to sodium phosphate is 0.2:1 to 0.6:

1. The multiple pH value changing aging process described in step (3) is as follows: First, add a portion of sodium aluminate solution to the second reaction slurry to control the pH value to 11.5 to 13.5 and age for 0.05 to 0.5 hours; Second, adjust the pH value to 8.5 to 10.5 and age for 0.05 to 0.5 hours; Third, adjust the pH value to 4.5 to 6.3 and age for 0.05 to 0.5 hours; Repeat the three-step pH value changing process multiple times; The aging temperature is 60 to 98℃; The pH value of the first gelling reaction in step (1) is controlled at 5 to 6; The pH value is controlled at 8.0 to 10.5 when the second gelling reaction in step (2) ends.

2. The method according to claim 1, characterized in that: In the multi-metal solution described in step (1), the weight concentration of W (as WO3) is 5-140 g / L, the weight concentration of Ni (as NiO) is 5-110 g / L, and the weight concentration of Al (as Al2O3) is 2-90 g / L.

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

4. The method according to claim 1, characterized in that: In the nickel-containing solution described in step (2), the weight concentration of Ni, calculated as NiO, is 10 to 130 g / L.

5. The method according to claim 1, characterized in that: The phosphate ester compound mentioned in step (2) is one or more of the following: octadecyl ether phosphate, alkylphenol ether phosphate, isotridecyl ether phosphate, lauryl ether phosphate, castor oil phosphate, octadecyl phosphate, and lauryl phosphate.

6. The method according to claim 1, characterized in that: The molar ratio of the added phosphate ester compound to Ni in the nickel-containing solution is 0.8:1 to 6.0:

1.

7. The method according to claim 1, characterized in that: The conditions for the second gelation reaction described in step (2) are: reaction temperature of 30-95℃ and reaction time of 0.5-2.5 hours.

8. The method according to claim 1, characterized in that: The aging process with varying pH values ​​described in step (3) is repeated 2 to 8 times.

9. The method according to claim 1, characterized in that: The sodium aluminate solution mentioned in step (3) has an Al concentration of 5-70 g / L (calculated as Al2O3). The sodium aluminate solution is divided into equal portions by volume, with the number of portions corresponding to the number of aging cycles.

10. The method according to claim 1, characterized in that: The Ni added through the nickel-containing solution accounts for 55% to 85% of the total Ni in the obtained hydrorefining catalyst, calculated as NiO.

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

12. The method according to claim 1, characterized in that: The roasting conditions for step (4) are as follows: roasting temperature is 350~700℃, and roasting time is 1~24 hours.

13. The method according to claim 1, characterized in that: The hydrogen reduction in step (4) is a programmed temperature reduction, specifically including: the precursor is in a hydrogen atmosphere with a hydrogen purity greater than 99 v% and a hydrogen flow rate of 150~700 mL / min; in the first stage, the heating rate is 3~10℃ / min, from room temperature to 300~550℃, and held at the temperature for 1~5 hours; in the second stage, the temperature is increased to 600~750℃ at a heating rate of 0.5~5℃ / min, and held at the temperature for 2~8 hours; the heating rate in the second stage is at least 1℃ / min lower than the heating rate in the first stage.

14. A hydrorefining catalyst prepared by the method according to any one of claims 1 to 13, characterized in that: The catalyst comprises transition metal phosphides and alumina. Based on the weight of the catalyst, the total content of transition metal phosphides is 35%~82%, and the content of alumina is 18%~65%. The transition metal phosphides are WP and Ni2P. The weight ratio of Ni2P in the surface phase to Ni2P in the bulk phase is 2.5:1~7.0:1, and the weight ratio of WP in the surface phase to WP in the bulk phase is 2.5:1~6.5:

1.

15. The catalyst according to claim 14, characterized in that: The Ni / W molar ratio of the hydrorefining catalyst is 0.1:1 to 12:

1.

16. The catalyst according to claim 14, characterized in that: The average particle diameter of the transition metal phosphide is 2-7 nm.

17. The catalyst according to claim 14, characterized in that: The pore size distribution of the hydrorefining catalyst is as follows: pores with a diameter of less than 6 nm account for 2% to 10% of the total pore volume, pores with a diameter of 6 to 10 nm account for 45% to 67% of the total pore volume, pores with a diameter of 10 to 15 nm account for 12% to 35% of the total pore volume, and pores with a diameter of more than 15 nm account for 10% to 28% of the total pore volume.

18. The application of a hydrorefining catalyst prepared by any one of claims 1 to 13 in ultra-deep hydrodesulfurization, denitrification and hydrodearomatics removal of heavy diesel fractions, wherein the aromatic content of the heavy diesel fraction is 50 wt% to 85 wt% and the cetane number is less than 24.