A process for the preparation of a phosphide hydrofining catalyst

Abstract

The application discloses a preparation method of a phosphide hydrofining catalyst, and comprises the following contents: (1) adding a W-Ni-Al solution into a reaction tank, dropping a mixed precipitant into the reaction tank to carry out a pH value increasing gelation reaction, adding a nickel-containing solution every time, adding a phosphate compound at the beginning of the second last time of increasing, and obtaining a slurry after the gelation reaction is finished; wherein the mixed precipitant is a mixture of ammonia and a sodium phosphate solution; (2) carrying out at least two times of "pH value decreasing aging" on the slurry, and obtaining an aging product after the aging is finished; and (3) preparing the aging product into the phosphide hydrofining catalyst. The catalyst prepared by the method has high surface phosphide content, and is suitable for application in diesel fraction ultra-deep hydrodesulfurization and denitrification reactions.

Description

TECHNICAL FIELD

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

[0002] At present, crude oil is becoming increasingly heavy and poor, coupled with the sustained development of the world economy and the increasingly stringent environmental protection regulations, a large amount of light clean fuel needs to be produced. The development and use of ultra-low sulfur or even sulfur-free gasoline and diesel are the trend of clean fuel development in the world today. It is an urgent need for oil refining enterprises to develop catalysts with higher activity. Phosphide catalysts as a new type of hydrogenation catalyst have become a research hotspot. In transition metal phosphides, the smallest structural unit is a triangular prism structure, these triangular prism units form different lattice types in different combination ways, and the phosphorus atoms occupy the voids in the triangular prism. The structure of phosphide is a triangular prism unit, which is similar to a spherical shape, and phosphide can expose more numbers of coordination unsaturated surface atoms than sulfide, thereby having a higher surface active site density.

[0003] CN202110241298.5 discloses a preparation method of a phosphide hydrogenation catalyst, which specifically comprises the following steps: (1) preparation of a precursor: mixing a soluble metal salt solution and a dimethyl imidazole solution, and then performing aging, centrifugation and drying to obtain the precursor; (2) preparation of the catalyst: heating the precursor and sodium hypophosphite to obtain a phosphide hydrogenation catalyst. The hydrogenation desulfurization catalyst prepared by phosphorization by using the MOF material with developed pores as the precursor has a smaller pore volume and specific surface area, and the hydrogenation activity of heavy feedstock is not obviously improved.

[0004] CN111822015B discloses a preparation method of a hydrofining catalyst. The method comprises the following steps: (1) preparing mixed solution A containing a transition metal and mixed solution B; (2) mixing solution A and an alkali sodium metaaluminate solution and adding them into a reaction tank to perform a gelation reaction to obtain slurry I, and then aging; (3) mixing solution B and the alkali sodium metaaluminate solution and adding them into the aged slurry I to perform a gelation reaction to obtain slurry II, adding an organic phosphorus compound, and then aging; (4) drying, shaping and calcining the obtained material to obtain a phosphide catalyst precursor; and (5) performing a hydrogen temperature programmed reduction on the obtained material to obtain a hydrofining catalyst. The catalyst prepared by the method has more active centers, but the content of surface phase metal is small, and the hydrogenation activity needs to be further improved.

[0005] CN106694004A discloses a transition metal phosphide catalyst and a preparation method thereof, and the catalyst is prepared by using a coprecipitation-programmed reduction method. The precipitation method is as follows: under stirring, a mixed solution of Mg(NO3)2·6H2O, Al(NO3)3·9H2O and transition metal (Fe, Co and Ni) salt and a precipitant NaOH solution are slowly and dropwise added into a Na2HPO4 solution at the same time to perform a precipitation reaction. This method directly performs a coprecipitation reaction on the metal solution, which is easy to cause local agglomeration of the active metal, thereby affecting the performance of the catalyst.

[0006] At present, the number of active centers of the phosphide catalyst prepared by using the coprecipitation method can be greatly increased. However, compared with the supported phosphide catalyst, although the active metal content of the phosphide catalyst prepared by using the coprecipitation method is high, the pore volume and specific surface area thereof are small, the phosphide particle sizes are different, and the content of the phosphide in the surface phase is small, which affects the utilization rate of the active metal. Therefore, how to increase the pore volume and specific surface area of the phosphide catalyst prepared by using the coprecipitation method, increase the content of the active metal in the surface phase of the catalyst, and reduce the phosphide grain size are the main problems faced by the preparation of the phosphide catalyst by using the coprecipitation method. SUMMARY

[0007] In view of the deficiencies of the prior art, the present application provides a preparation method of a phosphide hydrofining catalyst. The catalyst prepared by the method of the present application is a bulk phase hydrogenation catalyst with high content of surface phase phosphide, more active centers, and small phosphide grain size, and is suitable for application in diesel fraction ultra-deep hydrodesulfurization and denitrification reactions.

[0008] The preparation method of the phosphide hydrofining catalyst of the present application comprises the following contents:

[0009] (1) W-Ni-Al solution is added into a reaction tank, and a mixed precipitant is dropped into the reaction tank to perform a pH value increasing gelation reaction, the pH value increasing is at least more than 3 times, one portion of nickel-containing solution is added each time, a phosphate ester compound is added at the beginning of the second last increasing, and slurry is obtained after the gelation reaction is completed; wherein the mixed precipitant is a mixture of ammonia water and sodium phosphate solution;

[0010] (2) the slurry obtained in step (1) is subjected to at least two times of pH value decreasing aging, and the pH value decreasing aging process is as follows: in the first step, one portion of sodium metaaluminate solution is dropped into the slurry, the pH value is controlled at 11.5-13.5, and the aging time is 0.05-0.5 hours; in the second step, the pH value is adjusted to 8.5-10.5, and the aging time is 0.05-0.5 hours; in the third step, the pH value is adjusted to 4.5-6.3, and the aging time is 0.05-0.5 hours; after the aging is completed, an aging product is obtained;

[0011] (3) the aging product is filtered, dried, shaped, washed, and calcined to obtain a phosphide catalyst precursor, which is then reduced by hydrogen to obtain a phosphide hydrofining catalyst.

[0012] In the method, the ammonia water concentration in step (1) is 5wt%-10wt%, the weight concentration of the sodium phosphate solution is 8wt%-20wt%, and the molar ratio of ammonia to sodium phosphate in the mixed precipitant is 0.15:1-0.6:1.

[0013] In the method, the weight concentration of W in the W, Ni, and Al solution in step (1) is 5-120g / L, preferably 10-110g / L, the weight concentration of Ni is 5-90g / L, preferably 10-80g / L, and the weight concentration of Al is 2-90g / L, preferably 6-85g / L; when the W, Ni, and Al solution is prepared, the commonly used tungsten source is ammonium metatungstate, the aluminum source is one or more of aluminum nitrate, aluminum sulfate, aluminum chloride, and aluminum acetate, and the nickel source is one or more of nickel sulfate, nickel nitrate, and nickel chloride.

[0014] In the method, the pH value increasing range of the pH value increasing gelation reaction in step (1) is 5.0-6.5 to 8.0-10.5, and the constant time after each pH value increasing is 0.05-0.5 hours; the pH value increasing amplitude can be the same or different each time, and the pH value increasing amplitude is preferably not greater than the pH value increasing amplitude of the previous time; at the beginning, the pH value is first adjusted to the initial value by using the precipitant.

[0015] In the method, the increasing number of times in step (1) is preferably 4-8 times.

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

[0017] In the method, the weight concentration of Ni in the nickel-containing solution in step (1) is 5-150g / L, preferably 15-145g / L; when the nickel-containing solution is prepared, the nickel source is one or more of nickel sulfate, nickel nitrate, and nickel chloride; the number of times of adding the nickel-containing solution is the same as the number of times of increasing the pH value, and the volume of the nickel-containing solution added each time can be the same or different; the Ni added by the nickel-containing solution accounts for 53%-83%, preferably 58%-80%, of the total Ni in the obtained hydrofining catalyst.

[0018] In the method, the phosphate compound 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 phosphate compound added is in a molar ratio of 0.6:1 to 5.0:1, preferably 1.2:1 to 4.5:1, to Ni in the nickel-containing solution.

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

[0020] In the method, the number of times of the "pH decreasing aging" in step (2) is generally 2 to 8. In the aging process, in addition to using sodium metaaluminate solution in the first step of adjusting pH, the acid and base used for adjusting pH in the rest of the steps can be inorganic salts, inorganic acids and inorganic bases not containing aluminum element. 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 water and sodium hydroxide. The concentration and amount of the acid and base solution can be adjusted according to the actual needs of preparation.

[0021] In the method, the number of times of the "pH decreasing aging" in step (2) is generally 2 to 8. In the aging process, in addition to using sodium metaaluminate solution in the first step of adjusting pH, the acid and base used for adjusting pH in the rest of the steps can be inorganic salts, inorganic acids and inorganic bases not containing aluminum element. 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 water and sodium hydroxide. The concentration and amount of the acid and base solution can be adjusted according to the actual needs of preparation.

[0022] In the method, the amount of Al added by sodium metaaluminate solution in step (2) accounts for 5% to 50%, preferably 6% to 45%, of the total Al in the obtained hydrofining catalyst in terms of Al2O3.

[0023] In the method, the drying, shaping and washing in step (3) can be carried out by conventional methods in the art. The drying conditions are as follows: drying at 40 to 150°C for 1 to 48 hours, preferably drying at 50 to 120°C for 4 to 36 hours. In the shaping process, one or more of conventional shaping aids such as a peptizing agent, an extrusion aid and the like can be added as needed. The peptizing agent is one or more of hydrochloric acid, nitric acid, sulfuric acid, acetic acid, oxalic acid and the like, and the extrusion aid refers to a substance that is beneficial to extrusion molding, such as one or more of sesbania gum, carbon black, graphite powder, citric acid and the like. The amount of the extrusion aid accounts for 1 wt% to 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 and the like), and the washing is carried out until neutral.

[0024] In the method, the calcination condition in step (3) is that the calcination temperature is 350-700 DEG C, preferably 400-650 DEG C, and the calcination time is 1-24 hours, preferably 2-12 hours.

[0025] In the method, the hydrogen temperature programmed reduction process in step (3) is that the precursor is under hydrogen atmosphere, the hydrogen purity is greater than 99v%, the hydrogen flow rate is 150-700 mL / min, preferably 250-600 mL / min, the temperature increasing rate is 3-10 DEG C / min, the temperature is increased from room temperature to 300-550 DEG C, the temperature is kept constant for 1-5 hours, then the temperature is increased to 600-750 DEG C at a temperature increasing rate of 0.5-5 DEG C / min, the temperature is kept constant for 2-8 hours, and the temperature increasing rate in the second stage is at least 1 DEG C / min lower than that in the first stage, preferably at least 2 DEG C / min lower.

[0026] In the method, in order to prevent the phosphide from reacting with air, the prepared catalyst sample is passivated by O2 / N2 passivation gas with an oxygen volume concentration of 0.5%-3% for 1-5 hours before being exposed to air.

[0027] The application of the hydrofining catalyst in the ultra-deep hydrodesulfurization, denitrification reaction and hydrodearomatization of heavy diesel oil fraction, wherein the content of aromatic hydrocarbon in the heavy diesel oil fraction is 50wt%-85wt%, and the cetane number is less than 24.

[0028] Compared with the prior art, the application has the following advantages:

[0029] 1. In the application, the W, Ni and Al-containing solution is precipitated by adopting the pH value stepwise increasing gelation method at a specific pH value, so that the generation of large particle oxides in the gelation process is prevented, the active metals are uniformly dispersed, the addition of part of the active metal Ni in the pH value stepwise increasing process is more conducive to the dispersion of the active metals, the hydrogenation activity of the catalyst is greatly improved, the phosphate compound is added in the gelation reaction, the phosphate compound is uniformly distributed on the surface of the catalyst as a phosphorus source, meanwhile, due to the increase of the content of the surface active metal, the addition of the phosphate compound makes the surface active metal in the precursor uniformly dispersed, and the interaction between W and Ni and the carrier is weakened, so that W and Ni are easily phosphorized, and the phosphide is prevented from gathering on the surface of the catalyst.

[0030] 2. In the preparation of the catalyst by the coprecipitation method, the ammonia water and sodium phosphate with a specific molar ratio are adopted, so that the properties of the generated materials are controlled, the metal oxide particle size is small and uniform, the pore volume and specific surface area of the bulk catalyst are increased, and the diffusion efficiency of the catalytic process is improved due to the suitable pore diameter.

[0031] 3、The present application swings pH value during aging and adds sodium metaaluminate solution in batches, the amorphous oxide in the oxide particle is dissolved by swinging pH value, the size of the oxide particle is modified by adding sodium metaaluminate solution, the growth of the oxide particle is controlled by swinging pH value for many times, the oxide particle is more uniform, the particle is small, more active metal is exposed in the surface phase, the macropore in the bulk phase catalyst is increased, the macromolecular reactant is easy to pass through the pore, at the same time, the surface hydroxyl is increased by introducing aluminum by sodium metaaluminate solution, the adhesion of the oxide is further enhanced, which is beneficial to the shaping of the catalyst.

[0032] The method of the present application controls the preparation step and preparation condition comprehensively, the phosphide particle in the bulk phase catalyst is small, the active metal in the surface phase of the catalyst is uniformly dispersed, the metal utilization rate is improved, the surface phase of the catalyst has high hydrogenation active site, the hydrogenation activity of treating heavy oil is improved, the preparation cost of the catalyst is reduced, which is especially beneficial to the aromatic saturation of heavy oil, effectively reduces the content of polycyclic aromatic hydrocarbon, and improves the cetane number. DETAILED DESCRIPTION

[0033] In the present application, the specific surface area, pore volume and pore distribution are determined by low temperature liquid nitrogen adsorption method, the mechanical strength is determined by side pressure method, and the diameter of the transition metal phosphide particle is determined by TEM technology. In the present application, wt% is mass fraction, and v% is volume fraction. The phosphide content in the surface phase of the catalyst is determined by X-ray photoelectron spectroscopy (XPS), and the phosphide content in the bulk phase of the catalyst is determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). First, the active metal content in the surface phase and the bulk phase of the transition metal oxide precursor of the catalyst of the present application is determined, and then converted into the transition metal phosphide content in the surface phase and the bulk phase of the catalyst. Example 1

[0034] Ammonium metatungstate, nickel chloride and aluminum chloride were added to a dissolving tank 1 containing deionized water to prepare a W, Ni, Al-containing solution, in which the concentration of W (as WO3) was 42 g / L, the concentration of Ni (as NiO) was 34.6 g / L, and the concentration of Al (as Al2O3) was 53.2 g / L. The Ni-containing solution was prepared so that the Ni content was 70% of the total Ni (as NiO) in the obtained hydrofining catalyst, and the solution was divided into five equal parts by volume. The Al content in the sodium aluminate solution was 30% of the total Al (as Al2O3) in the obtained hydrofining catalyst, and the solution was divided into five equal parts by volume. Deionized water was placed in a reaction tank, the W, Ni, Al-containing solution was placed in the reaction tank, the reaction temperature was 60°C, and ammonia water and sodium phosphate solution were added dropwise, with the molar ratio of ammonia to sodium phosphate in the ammonia water and sodium phosphate solution being 0.29:1. The pH value was controlled to be 5.5, and the ammonia water and sodium phosphate solution were continuously added dropwise. The pH value was raised by 0.7 each time, and the final pH value at the end of the process was adjusted to be 9.0. After the pH value was adjusted each time, one part of the Ni-containing solution was added, and the pH value of the adjusted reaction slurry was kept constant for 10 minutes. Castor oil phosphate was added when the pH value was raised for the fourth time, with the molar ratio of castor oil phosphate to the total number of Ni atoms in the Ni-containing solution being 2.9, and a precipitate slurry containing nickel, tungsten and aluminum was formed. The obtained slurry was aged, with the aging temperature being 76°C. During the aging process, one part of the sodium aluminate solution was added first, and the pH value was controlled to be 13.1. After 0.15 hours, the aging pH value was controlled to be 9.5, and after 0.2 hours, the pH value was controlled to be 5.0, and the aging time was 0.2 hours. The above process was repeated five 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 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 80°C for 9.0 hours, and 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, with the hydrogen flow rate being 320 mL / min, the heating rate being 7°C / min, the temperature being raised from room temperature to 430°C, the temperature being kept constant for 3.0 hours, the temperature being raised to 700°C at a heating rate of 3.0°C / min, and the temperature being kept constant for 5 hours. To prevent the phosphide from reacting violently with air, the catalyst sample was passivated with a 2% O2 / N2 passivation gas for 3 hours before it was exposed to air to obtain a hydrofining catalyst A. The composition and main physicochemical properties of the catalyst are shown in Table 1. Example 2

[0035] Ammonium metatungstate, nickel chloride and aluminum chloride were added to a dissolving tank 1 containing deionized water to prepare a W, Ni, Al-containing solution, in which the concentration of W (as WO3) was 50 g / L, the concentration of Ni (as NiO) was 25.2 g / L, and the concentration of Al (as Al2O3) was 58.5 g / L. The Ni-containing solution was prepared so that the Ni content was 65% of the total Ni (as NiO) in the obtained hydrofining catalyst, and the solution was divided into six equal parts by volume. The Al content in the sodium aluminate solution was 25% of the total Al (as Al2O3) in the obtained hydrofining catalyst, and the solution was divided into six equal parts by volume. Deionized water was placed in a reaction tank, and the W, Ni, Al-containing solution was placed in the reaction tank. The reaction temperature was 65°C. 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 0.30:1. The pH value was controlled to be 5.2, and the ammonia water and sodium phosphate solution were continuously added dropwise. The pH value was raised by 0.8 each time, and the final pH value at the end of the process was adjusted to be 10.0. After the pH value was adjusted each time, one part of the Ni-containing solution was added. The pH value of the adjusted reaction slurry was kept constant for 12 minutes. When the pH value was raised for the fifth time, lauryl alcohol ether phosphate was added. The molar ratio of lauryl alcohol ether phosphate to the total number of Ni atoms in the Ni-containing solution was 2.5. A precipitate slurry containing nickel, tungsten and aluminum was formed. The obtained slurry was aged. The aging temperature was 80°C. During the aging process, one part of the sodium aluminate solution was first added, and the pH value was controlled to be 13.3. After 0.2 hours of aging, the pH value was controlled to be 9.7. After 0.15 hours of aging, the pH value was controlled to be 5.4. After 0.2 hours of aging, the above process was repeated six times, and the aging process was completed. The aged slurry was filtered, and the filter cake was dried at 90°C for 9 hours. The dried filter cake was crushed and extruded into a strip. The extruded strip was washed with deionized water at room temperature until it was neutral. The washed extruded strip was dried at 80°C for 10.0 hours. The dried material was calcined at 520°C for 5 hours to obtain a phosphide catalyst precursor B. The precursor B was calcined in a pure hydrogen atmosphere. The hydrogen flow rate was 350 mL / min, the temperature was raised from room temperature to 450°C at a rate of 6°C / min, and then the temperature was kept constant for 3.5 hours. The temperature was raised to 660°C at a rate of 3.0°C / min, and then the temperature was kept constant for 6 hours. To prevent the phosphide from reacting violently 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 B. The composition and main physicochemical properties of the catalyst are shown in Table 1. Example 3

[0036] Ammonium metatungstate, nickel chloride and aluminum chloride were added to a dissolving tank 1 containing deionized water to prepare a W, Ni, Al-containing solution, in which the concentration of W (as WO3) was 30 g / L, the concentration of Ni (as NiO) was 34.0 g / L, and the concentration of Al (as Al2O3) was 50.7 g / L. The Ni-containing solution was prepared in which Ni accounted for 63% of the total Ni (as NiO) in the obtained hydrofining catalyst, and was divided into 5 equal parts by volume. The Al in the sodium aluminate solution accounted for 35% of the total Al (as Al2O3) in the obtained hydrofining catalyst, and was divided into 6 equal parts by volume. Deionized water was placed in a reaction tank, the W, Ni, Al-containing solution was placed in the reaction tank, the reaction temperature was 55°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 5.7, the ammonia water and sodium phosphate solution were continuously added dropwise, the pH value was adjusted to be 9.2 at the end by 5 times of pH value adjustment, the pH value was adjusted by 0.7 each time, and after the adjustment of the pH value each time, one part of the Ni-containing solution was added, the pH value of the adjusted reaction slurry was kept constant for 15 minutes, at the beginning of the fourth time of pH value adjustment, octadecyl ether phosphate was added, the molar ratio of octadecyl ether phosphate to the total number of Ni atoms in the Ni-containing solution was 2.6, a precipitate slurry containing nickel, tungsten and aluminum was generated, the obtained slurry was aged, the aging temperature was 83°C, one part of the sodium aluminate solution was added first during the aging, the pH value was controlled to be 12.8, the aging time was 0.15 hours, then the aging pH value was controlled to be 9.8, the aging time was 0.15 hours, then the pH value was controlled to be 5.3, the aging time was 0.2 hours, the above operation was repeated 6 times, and the aging was ended. The aged slurry was filtered, the filter cake was dried at 80°C for 1 hour, was rolled and was extruded into a strip. The extruded product was washed with deionized water at room temperature until neutral. The washed product was dried at 110°C for 9.0 hours, the dried product was calcined at 510°C for 4 hours, and a phosphide catalyst precursor C was obtained. The precursor C was calcined in a pure hydrogen atmosphere, the hydrogen flow rate was 450 mL / min, the temperature was raised from room temperature to 440°C at a rate of 6°C / min, was kept constant at 440°C for 3.6 hours, was raised to 680°C at a rate of 3.5°C / min, and was kept constant at 680°C for 4 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 2.2% for 4 hours before the catalyst sample contacted with air, and a hydrofining catalyst C was obtained. The catalyst composition and main physicochemical properties are shown in Table 1. Example 4

[0037] Ammonium metatungstate, nickel chloride and aluminum chloride were added into a dissolving tank 1 containing deionized water to prepare a W, Ni and Al-containing solution, in which the weight concentration of W (as WO3) was 46 g / L, the weight concentration of Ni (as NiO) was 20.0 g / L, and the weight concentration of Al (as Al2O3) was 53.6 g / L. The Ni-containing solution was prepared, in which the Ni accounted for 73% of the total Ni (as NiO) in the obtained hydrofining catalyst, and was divided into 6 equal parts by volume. The Al in the sodium aluminite solution accounted for 33% of the total Al (as Al2O3) in the obtained hydrofining catalyst, and was divided into 5 equal parts by volume. Deionized water was placed in a reaction tank, the W, Ni and Al-containing solution was placed in the reaction tank, the reaction temperature was 68℃, 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 0.38:1, the pH value was controlled to be 5.2, the ammonia water and sodium phosphate solution were continuously added dropwise, the pH value was adjusted to 8.8 at the end through 6 times of pH value adjustment, and the pH value was adjusted to 0.6 each time. After the pH value was adjusted to the adjusted value each time, one part of the Ni-containing solution was added, the pH value of the adjusted reaction slurry was kept constant for 13 minutes, and at the beginning of the fifth time of pH value adjustment, isomeric tridecanol ether phosphate was added, the molar ratio of isomeric tridecanol ether phosphate to the total number of Ni atoms in the Ni-containing solution was 2.7, a precipitate slurry containing nickel, tungsten and aluminum was generated, the obtained slurry was aged, the aging temperature was 82℃, and during the aging, one part of the sodium aluminite solution was added first, the pH value was controlled to be 13.0, the aging time was 0.2 hours, then the aging pH value was controlled to be 9.3, the aging time was 0.15 hours, then the pH value was controlled to be 4.8, the aging time was 0.15 hours, and the above operation process was repeated 5 times to end the aging. The aged slurry was filtered, the filter cake was dried at 110℃ for 7 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 85℃ for 9.5 hours, and 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, the hydrogen flow rate was 380 mL / min, the heating rate was 6 ℃ / min, the temperature was increased from room temperature to 450℃, and after being kept at 450℃ for 4.0 hours, the temperature was increased to 690℃ at a heating rate of 3.2 ℃ / min, and was kept at 690℃ 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 4 hours before being exposed to air to obtain a hydrofining catalyst D. The catalyst composition and main physicochemical properties are shown in Table 1.

[0038] Comparative Example 1

[0039] The reference agent G was prepared according to the preparation method of Example 3 of CN111822015A, and the specific process was as follows:

[0040] The components of catalyst C in Table 1 were added to a 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 NiO, and the weight concentration of W in the mixed solution A was 20 g / L as WO3. A dissolving tank 2 was added with nickel nitrate to prepare a mixed solution B, the weight concentration of Ni in the mixed solution B was 28 g / L as NiO. A reaction tank was added with tetrapropyl ammonium bromide and deionized water, 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 Al2O3 and the mixed solution A were added to the reaction tank in parallel flow, the gelation temperature was kept at 53°C, the pH value was controlled at 7.5 during the parallel flow gelation reaction, the gelation time was controlled at 1.3 hours, and a precipitate slurry I was generated. The precipitate slurry I was aged under stirring, the stirring speed was 215 rpm, 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 Al2O3 were added to the slurry I in parallel flow, the molar ratio of phenylethylamine to nickel in the mixed solution B was 1.3:1, the gelation temperature was kept at 52°C, the pH value was controlled at 8.7 during the parallel flow gelation reaction, and the gelation time was controlled at 2.7 hours, and a precipitate slurry II was generated. Hexanediamine tetramethylene phosphonic acid was added to the precipitate slurry II, the molar ratio of hexanediamine tetramethylene phosphonic acid to transition metals in the final prepared hydrofining catalyst was 4.0:1, the stirring speed was 380 rpm, 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 shaped. After the shaping, the precursor C of the phosphide catalyst was obtained by calcining at 490°C for 6 hours. The precursor C was heated in a hydrogen atmosphere, the hydrogen flow rate was 450 mL / min, the heating rate was 5.8°C / min, the temperature was increased from room temperature to 510°C, the temperature was kept constant for 5 hours, the temperature was increased to 710°C at a heating rate of 3.2°C / min, and 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 1.1% for 4 hours before the catalyst sample was exposed to air, and the hydrofining catalyst E was obtained. In the hydrofining catalyst E, the weight of the nickel and tungsten introduced through the mixed solution A accounted for 55% of the weight of the 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.

[0041] Comparative Example 2

[0042] The reference agent F was prepared according to Example 1, all the sodium metaaluminate solution was added at one time during the aging process of the precipitate slurry containing nickel, tungsten, and aluminum, and a fixed value was used for the aging pH value. The specific preparation process is as follows:

[0043] Ammonium metatungstate, nickel chloride and aluminum chloride were added to a dissolving tank 1 containing deionized water to prepare a W, Ni, Al-containing solution, in which the concentration of W (as WO3) was 42 g / L, the concentration of Ni (as NiO) was 34.6 g / L, and the concentration of Al (as Al2O3) was 53.2 g / L. The Ni-containing solution was prepared, in which the Ni accounted for 70% of the total Ni (as NiO) in the obtained hydrofining catalyst, and the Ni-containing solution was divided into 5 equal parts by mass. The Al in the sodium metaaluminate solution accounted for 30% of the total Al (as Al2O3) in the obtained hydrofining catalyst. Deionized water was placed in a reaction tank, and the W, Ni, Al-containing solution was placed in the reaction tank. The reaction temperature was 60°C. 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 0.29:1. The pH value was controlled to be 5.5. The ammonia water and sodium phosphate solution were continuously added dropwise. The final pH value at the end of the process was adjusted to be 9.0 by 5 times of pH value increasing, and the pH value was increased by 0.7 each time. After the pH value was adjusted each time, one part of the Ni-containing solution was added. The pH value of the adjusted reaction slurry was kept constant for 10 minutes. Castor oil phosphate was added when the pH value was increased for the fourth time, and the molar ratio of castor oil phosphate to the total number of Ni atoms in the Ni-containing solution was 2.9. A precipitate slurry containing nickel, tungsten and aluminum was generated. The obtained slurry was aged, and the aging temperature was 76°C. The total sodium metaaluminate solution was added during the aging process. The aging pH value was controlled to be 8.5. The aging time was 2 hours. The aging process was completed. The aged slurry was filtered, and the filter cake was dried at 100°C for 8 hours. The filter cake was rolled and extruded into a strip. The extruded product was washed with deionized water at room temperature until it was neutral. The washed product was dried at 80°C for 9.0 hours. The dried product 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 at a hydrogen flow rate of 320 mL / min and a heating rate of 7°C / min from room temperature to 430°C. After being kept at 430°C for 3.0 hours, the temperature was increased to 700°C at a heating rate of 3.0°C / min. The temperature was kept at 700°C for 5 hours. To prevent the phosphide from reacting violently with air due to oxidation, 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 F. The composition and main physicochemical properties of the catalyst are shown in Table 1.

[0044] Comparative Example 3

[0045] A reference agent J was prepared according to Example 1. In the preparation process, all the nickel was added to the W, Ni, Al-containing solution, and no Ni-containing solution was prepared. The pH value was not increased during the gelation reaction, and the reaction was carried out at a fixed pH value. The specific preparation process is as follows:

[0046] Ammonium metatungstate, nickel chloride and aluminum chloride were added to a dissolving tank 1 containing deionized water to prepare a W, Ni, Al-containing solution, in which the concentration of W (as WO3) was 42 g / L, the concentration of Ni (as NiO) was 82.0 g / L, and the concentration of Al (as Al2O3) was 53.2 g / L. Sodium aluminate solution was prepared by dissolving sodium aluminate in deionized water. The Al content in the sodium aluminate solution was 30% of the total Al (as Al2O3) in the obtained hydrofining catalyst. The sodium aluminate solution was divided into five equal parts by volume. Deionized water was added to a reaction tank, and the W, Ni, Al-containing solution was added to the reaction tank. The reaction temperature was 60°C. 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 0.25:1. The pH value at the end of the reaction was controlled at 8.0. The reaction time was 2.0 hours. Castor oil phosphate was added at the end of the reaction. The molar ratio of castor oil phosphate to the total number of Ni atoms in the W, Ni, Al-containing solution was 2.0. A precipitate slurry containing nickel, tungsten and aluminum was obtained. The obtained slurry was aged. The aging temperature was 76°C. At the beginning of the aging, one part of the sodium aluminate solution was added, and the pH value was controlled at 13.1. The aging time was 0.15 hours. Then, the pH value was controlled at 9.5, and the aging time was 0.2 hours. Subsequently, the pH value was controlled at 5.0, and the aging time was 0.2 hours. The above process was repeated five times, and the aging was completed. The aged slurry was filtered, and the filter cake was dried at 100°C for 8 hours. The dried filter cake was crushed and extruded into a strip. The extruded strip was washed with deionized water at room temperature until neutral. The washed extruded strip was dried at 80°C for 9.0 hours. The dried extruded strip was calcined at 530°C for 5 hours to obtain a phosphide catalyst precursor G. The precursor G was calcined in a pure hydrogen atmosphere. The hydrogen flow rate was 320 mL / min. The temperature was raised from room temperature to 430°C at a rate of 7°C / min. The temperature was kept at 430°C for 3.0 hours. The temperature was raised to 700°C at a rate of 3.0°C / min. The temperature was kept at 700°C 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 the catalyst sample was exposed to air. A hydrofining catalyst G was obtained. The composition and main physicochemical properties of the catalyst are shown in Table 1.

[0047] Comparative Example 4

[0048] A reference agent H was prepared by using ammonia water as a precipitant according to Example 1.

[0049] Comparative Example 5

[0050] A reference agent I was prepared by using sodium phosphate solution as a precipitant according to Example 1.

[0051] Comparative Example 6

[0052] A reference agent J was prepared by using ammonia water and sodium phosphate according to Example 1. The molar ratio of ammonia (as NH3) to sodium phosphate was 0.8:1. Example 5

[0053] The present examples are catalyst activity evaluation experiments of the present application, and are compared with comparative catalysts. The present application A, B, C, D catalysts and comparative examples E, F, G, H, I, J catalysts are respectively used to carry out comparative evaluation experiments on 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 - 1 , and kept for 40 minutes 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 , hydrogen to oil volume ratio is 500:1, and the evaluation results are shown in Table 3. The types of sulfides and nitrogen compounds in the hydrogenation refined oil are detected by gas chromatography-atomic emission spectrometry detector (GC-AED), and the results are shown in Tables 4 and 5.

[0054] From the evaluation results, it can be seen that the catalyst of the present application has excellent hydrogenation activity, the phosphide particles in the catalyst are small, the phosphide in the surface phase is more, and the dispersion degree is high, not only has excellent hydrogenation desulfurization activity and hydrogenation denitrification activity, but also has excellent hydrogenation saturation performance, effectively reduces the aromatic hydrocarbon content of heavy distillate oil, and the polycyclic aromatic hydrocarbon content is reduced more obviously. The catalyst of the present application is used for processing heavy distillate oil, especially for processing poor diesel oil fraction with high aromatic hydrocarbon content and difficult to process, has excellent hydrogenation saturation, hydrogenation desulfurization and hydrogenation denitrification performance, effectively reduces the polycyclic aromatic hydrocarbon content, and improves the cetane number of diesel oil.

[0055] Table 1 Catalyst composition and properties prepared by examples and comparative examples

[0056] Catalyst No. A B C D E F [Ni2P, wt%] 41 36 46 37 53 41 WP, wt% 21 25 15 23 18 21 Al203, wt% balance balance balance balance balance balance Specific surface area, m 2 / g]] 318 313 325 331 273 254 Pore volume, mL / g 0.446 0.437 0.458 0.464 0.383 0.349 Pore distribution < 4 nm 5.83 6.43 5.01 4.51 8.92 17.58 4 nm to 6 nm 4.45 5.46 4.24 3.92 26.75 30.68 6 nm to 10 nm 58.31 57.62 58.47 58.96 16.85 30.12 10 nm to 15 nm 16.21 15.01 16.61 16.89 37.68 10.44 > 15 nm 15.20 14.48 15.67 15.72 9.80 11.18 Average diameter of transition metal phosphide particles, nm 4.5 4.7 4.3 4.4 5.3 14.5

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

[0058] Catalyst No. G H I J [Ni2P, wt%] 41 41 41 41 WP, wt% 21 21 21 21 Al203, wt% balance balance balance balance Specific surface area, m 2 / g]] 230 168 308 197 Pore volume, mL / g 0.338 0.245 0.435 0.298 Pore distribution < 4 nm 19.23 41.24 3.42 30.21 4 nm to 6 nm 33.54 28.62 5.19 23.52 6 nm to 10 nm 26.42 17.13 39.42. 20.12 10 nm to 15 nm 10.89 7.98 23.32 12.40 > 15 nm 9.92 5.03 28.65 13.75 Average diameter of transition metal phosphide particles, nm 15.2 7.9 24.5 10.8

[0059] Table 2 Weight content ratio of active metal oxides in surface phase and bulk phase of catalyst

[0060] Catalyst No. A B C D E F Table phase I Ni2P Bulk phase I Ni2P ]]> 5.91 5.62 5.74 5.85 1.22 2.04 Table phase I WP Bulk phase I WP ]]> 4.84 4.71 4.78 4.80 1.13 1.35

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

[0062] Catalyst No. G H I J Table phase I Ni2P Bulk phase I Ni2P ]]> 2.15 1.52 2.29 1.76 Table phase I WP Bulk phase I WP ]]> 1.49 1.18 1.58 1.34

[0063] Table 3 Main properties of raw oil

[0064] Item Analysis result Density (20°C), g / cm 3 ]] 0.9393 Distillation range, °C 162-384 S, pg / g 14980 N, pg / g 898 Aromatics, wt% 72.6 Polycyclic aromatics, wt% 46.8 Cetane number ＜24

[0065] Table 4 Catalyst activity evaluation results

[0066] Catalyst No. A B C D E F Density of the produced oil (20°C), g / cm 3 ]] 0.8672 0.8676 0.8672 0.8670 0.8682 0.8781 Distillation range, °C 166-368 168-369 164-367 163-366 172-371 179-377 S, pg / g 7.0 8.0 6.6 6.0 9.8 80.1 N, pg / g 4.0 4.4 3.8 3.5 8.5 49.7 Aromatics, wt% 34.1 34.8 33.8 33.6 38.8 47.9 Polycyclic aromatics, wt% 4.6 5.2 4.4 4.2 7.5 17.3 Cetane number 39.4 38.7 39.7 39.9 38.1 30.1

[0067] Table 4 (continued)

[0068] Catalyst No. G H I J Density of the produced oil (20°C), g / cm 3 ]] 0.8788 0.8813 0.8804 0.8809 Distillation range, °C 182-378 184-382 182-377 183-380 S, pg / g 89.1 154.3 101.2 131.8 N, pg / g 54.8 85.8 62.3 73.6 Aromatics, wt% 48.4 60.7 52.4 57.7 Polycyclic aromatics, wt% 18.2 23.2 19.9 23.2 Cetane number, 29.5 25.2 28.0 25.2

[0069] Table 5 Content of different nitrogen compounds in hydrofinished oil

[0070] Catalyst No. A B C D E F Nitrogen content in hydrofinished oil, pg / g 4.0 4.4 3.8 3.5 8.5 49.7 1-MCB, pg / g 1.9 2.0 1.8 1.7 3.9 22.9 1,8-BMCB, pg / g 1.5 1.3 1.5 1.4 2.7 16.8 1,4,8-TMCB, pg / g 0.6 0.7 0.5 0.4 1.9 10.0

[0071] Table 5 Content of different nitrogen compounds in hydrofinished oil

[0072] Catalyst No. G H I J Nitrogen content in hydrofinished oil, pg / g 54.8 85.8 62.3 73.6 1-MCB, pg / g 24.8 40.2 27.4 35.1 1,8-BMCB, pg / g 17.8 25.4 19.3 22.4 1,4,8-TMCB, pg / g 12.2 20.2 15.6 16.1

Claims

1. A method for preparing a phosphide hydrogenation refining catalyst, characterized in that... The process includes the following: (1) Adding W-Ni-Al solution to a reaction vessel, adding a mixed precipitant to the reaction vessel to carry out a pH-increasing gelation reaction, increasing the pH value at least 3 times, adding a portion of nickel-containing solution each time, adding a phosphate ester compound at the beginning of the second-to-last increase, and obtaining a slurry after the gelation reaction is completed; wherein the mixed precipitant is a mixture of ammonia and sodium phosphate solution; (2) The slurry obtained in step (1) undergoes at least two "pH-decreasing aging" processes, the pH-decreasing aging process is as follows: First, adding a portion of sodium aluminate solution to the slurry, controlling the pH at 11.5~13.5, aging for 0.05~0.5 hours; Second, adjusting the pH value to 8.5~10.5, aging for 0.05~0.5 hours; Third, adjusting the pH value to 4.5~6.3, aging for 0.05~0.5 hours; After aging, obtaining the aged product; (3) The aged product is filtered, dried, shaped, washed, and calcined to obtain a phosphide catalyst precursor, which is then reduced by hydrogen program temperature to obtain a phosphide hydrogenation refining catalyst. The concentration of ammonia in step (1) is 5wt% to 10wt%, the concentration of sodium phosphate solution is 8wt% to 20wt%, and the molar ratio of ammonia to sodium phosphate in the mixed precipitant is 0.15:1 to 0.6:

1.

2. The method according to claim 1, characterized in that: In the W-Ni-Al solution described in step (1), the weight concentration of W as WO3 is 5-120 g / L, the weight concentration of Ni as NiO is 5-90 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 pH increment range of the gelation reaction in step (1) is from the initial value of 5.0~6.5 to the final value of 8.0~10.

5. After each increment, the pH value is kept constant for 0.05~0.5 hours. The pH increment may be the same or different each time.

4. The method according to claim 3, characterized in that: The increase in pH value should not exceed the increase in pH value of the previous time.

5. The method according to claim 1, characterized in that: The increment number mentioned in step (1) is 4 to 8 times.

6. The method according to claim 1, characterized in that: The pH value increasing gelation reaction conditions in step (1) are: reaction temperature of 40-90℃ and reaction time of 0.3-5.0 hours.

7. The method according to claim 1, characterized in that: In step (1), the nickel-containing solution has a weight concentration of 5-150 g / L based on NiO. The number of nickel-containing solutions is the same as the number of times the pH value increases. The volume of each nickel-containing solution added is the same or different. The Ni added through the nickel-containing solution accounts for 53%-83% of the total Ni in the obtained hydrorefining catalyst based on NiO.

8. The method according to claim 1, characterized in that: The phosphate ester compound 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 phosphate ester compound added to Ni in the nickel-containing solution is 0.6:1 to 5.0:

1.

9. The method according to claim 1, characterized in that: The aging process described in step (2) is carried out at a temperature of 60–98°C.

10. The method according to claim 1, characterized in that: The number of times the "pH value decreasing aging" mentioned in step (2) is 2 to 8; during the aging process, except for the use of sodium aluminate solution in the first step of pH value adjustment, the acids and bases used to adjust the pH value are inorganic acids and bases that do not contain aluminum.

11. The method according to claim 1, characterized in that: In step (2), the number of sodium aluminate solution portions is the same as the number of aging cycles with decreasing pH value.

12. The method according to claim 1, characterized in that: In step (2), the Al added through sodium aluminate solution accounts for 5% to 50% of the total Al in the obtained hydrorefining catalyst, calculated as Al2O3.

13. The method according to claim 1, characterized in that: The roasting conditions in step (3) are: roasting temperature of 350~700℃ and roasting time of 1~24 hours.

14. The method according to claim 1, characterized in that: The hydrogen programmed temperature reduction process described in step (3) is as follows: the phosphide catalyst precursor is heated in a hydrogen atmosphere with a hydrogen purity greater than 99 vol% at a flow rate of 150-700 mL / min and a heating rate of 3-10 °C / min from room temperature to 300-550 °C. After holding the temperature for 1-5 hours, the temperature is increased to 600-750 °C at a heating rate of 0.5-5 °C / min and held for 2-8 hours.

15. The method according to claim 1, characterized in that: Before the prepared phosphide hydrorefining catalyst comes into contact with air, it is first passivated with O2 / N2 passivation gas with an oxygen volume concentration of 0.5% to 3% for 1 to 5 hours.