A process for preparing a hydrofining catalyst

Abstract

The application discloses a preparation method of a hydrofining catalyst, which comprises the following steps: (1) preparing a mixed solution A containing Al components and a nickel salt; preparing a mixed solution B of sodium tungstate and sodium molybdate; and preparing an Al component solution C; (2) adding the mixed solution B and an alkaline precipitator into the mixed solution A drop by drop to obtain a slurry D; (3) aging the slurry D, adding the solution C in batches during the aging process to obtain a slurry E; (4) performing vacuum filtration on the slurry E, performing primary health maintenance on a filter cake, adding a certain proportion of m deionized water into the filter cake after the primary health maintenance, performing a vacuum filtration process I, performing secondary health maintenance on the filter cake, adding a certain proportion of n deionized water into the filter cake, performing a filtration process II, and obtaining a filter cake F; and (5) drying the filter cake F, extruding the dried material into a strip shape, and performing calcination to obtain the hydrofining catalyst. The catalyst has high hydrogenation saturation performance and is particularly suitable for application in heavy distillate oil hydrogenation de-aromatic, ultra-deep desulfurization and denitrification reactions.

Description

Technical Field

[0001] This invention belongs to the field of catalyst preparation, specifically relating to a method for preparing a hydrorefining catalyst with high hydrodesulfurization, hydrodenitrogenation, and aromatic saturation activity. Background Technology

[0002] With the gradual increase in my country's oil quality requirements, after the sulfur content of diesel fuel was limited to below 10 μg / g, the requirements for aromatic content are also becoming increasingly stringent. The most effective way to meet the requirements for upgrading diesel fuel quality is to use highly active hydrogenation catalysts. Therefore, as one of the most active hydrogenation catalysts in the current refining market, bulk catalysts are very suitable for refineries to carry out diesel fuel quality upgrades due to their excellent performance.

[0003] The preparation methods for hydrorefining catalysts generally include impregnation, kneading, slurry preparation, ion exchange, and coprecipitation. Bulk catalysts are typically prepared using kneading or coprecipitation. However, due to limitations in the preparation method, kneading often results in uneven mixing of components, aggregation of active metals, and fails to promote synergistic effects between active metals, making it difficult for the catalyst to fully exert its activity. Furthermore, the preparation of bulk catalysts is greatly affected by the difficulty of molding, making it difficult to obtain catalysts with high metal content using the kneading method.

[0004] Coprecipitation, due to the characteristics of ionic reactions, allows for uniform mixing of components. Furthermore, it allows the use of relatively inexpensive sodium-containing raw materials to replace some more expensive or nitrogen-containing materials, significantly reducing catalyst raw material costs and nitrogen-containing wastewater treatment expenses. However, the introduction of large amounts of sodium ions makes complete removal from the bulk catalyst difficult, resulting in a large amount of sodium impurities in the coprecipitate. This leads to poor material adhesion, making it difficult to form or resulting in poor catalyst strength after forming. Simultaneously, the unremoved sodium impurities hinder the formation of catalyst pore structures, resulting in smaller pore volume and size, affecting diffusion efficiency during the catalytic reaction. In addition, excessively high sodium content in the bulk catalyst can cause active metal aggregation, reducing the catalyst's hydrogenation activity.

[0005] In the hydrorefining reaction of distillate oils, to improve the reaction efficiency of the catalyst's active sites, the catalyst needs to have a large pore size to facilitate the smooth passage of feed and product molecules through the catalyst channels during internal diffusion. Currently developed bulk catalysts, although containing high active metal content, have small pore sizes, affecting the diffusion efficiency of the catalytic reaction. Furthermore, high active metal content easily leads to excessive particle deposition, affecting the morphology of the sulfided MoS2 / WS2, reducing the amount of active phase formed, lowering the utilization rate of active metals, and resulting in waste of active metals.

[0006] CN1339985A discloses a method for preparing a mixed metal catalyst composition, and CN101153228A discloses a multi-metal bulk catalyst for ultra-deep hydrodesulfurization of diesel. Both of the above patents use the co-precipitation method to prepare hydrogenation catalysts, but the pore structure of the prepared catalysts is not ideal, with small pore volume and pore size.

[0007] CN114471593A and CN114471594A both disclose a method for preparing a hydrorefining catalyst. This method also employs a co-precipitation method and includes sodium salt removal treatment. This method selects to remove sodium salt after catalyst extrusion molding; however, in practice, if the sodium salt content is too high during catalyst preparation, the catalyst cannot be molded or has low strength after molding. Therefore, this method has certain requirements regarding the sodium content of the catalyst preparation raw materials. Furthermore, since the co-precipitation reaction products contain a large number of sodium ions, this method causes some sodium chloride crystals to precipitate and adhere to the internal pores during the drying process of the co-precipitated reactants, which also adversely affects the formation of the catalyst's pore structure. In addition, selecting to remove sodium salt after catalyst extrusion molding, the intermediate drying and extrusion processes increase the adsorption degree of sodium ions on the catalyst, making removal even more difficult.

[0008] CN109692693B discloses a hydrorefining catalyst and its preparation method. This method uses a two-stage co-current precipitation process to prepare a mixed precipitate of tungsten, molybdenum, and nickel as active metals. The process includes aging, drying, shaping, and calcination steps to successfully obtain the hydrorefining catalyst. However, this method fails to effectively control the particle size of the products generated during the co-current co-precipitation reaction. In particular, the second co-current co-precipitation, where the previous product slurry is co-precipitated again, can cause excessive aggregation or uneven particle size in the final product, thus affecting the distribution of active metals and the pore structure of the catalyst, ultimately impacting its hydrorefining activity.

[0009] The coprecipitation method for preparing bulk catalysts can affect the catalyst pore size and active metal distribution due to factors such as precipitation method and gelation conditions. This can lead to a reduction in the active phase of MoS2 / WS2 after sulfidation, resulting in hydrogenation activity that cannot reach the ideal state. Summary of the Invention

[0010] To address the problems existing in the prior art, this invention provides a method for preparing a hydrorefining catalyst. This invention uses inexpensive and environmentally friendly sodium-containing raw materials to prepare a bulk hydrorefining catalyst. An aluminum-containing solution is added in stages during the aging pH swing gelation process, combined with a specific impurity removal method to remove sodium impurities. The catalyst exhibits a suitable pore size distribution and well-dispersed active metals. The active metal particles are uniform and of suitable size, preventing excessive particle aggregation. This method also solves the problems of catalyst formation and activity inhibition when sodium content is high, significantly improving both catalyst strength and pore structure properties. The bulk catalyst prepared by this method exhibits high hydrosaturation performance and is particularly suitable for applications in the hydrodearomatization, ultra-deep hydrodesulfurization, and denitrification reactions of heavy distillate oils.

[0011] The method for preparing the hydrorefining catalyst of the present invention includes the following:

[0012] (1) Prepare a mixed solution A containing Al components and nickel salts; prepare a mixed solution B containing sodium tungstate and sodium molybdate; prepare a solution C containing Al components;

[0013] (2) Mixed solution A is used as the bottom water for co-precipitation reaction. Under high-speed stirring conditions, mixed solution B and alkaline precipitant are added dropwise to mixed solution A to obtain slurry D;

[0014] (3) The slurry D is aged by adding solution C in 2 to 8 times during the aging process to obtain slurry E;

[0015] (4) The slurry E is vacuum filtered to obtain a filter cake, and the filter cake is cured once. After curing, a certain proportion of m deionized water is added to the filter cake, and vacuum filtration process I is carried out. The filter cake is cured a second time, and a certain proportion of n deionized water is added to the filter cake, and vacuum filtration process II is carried out to obtain filter cake F.

[0016] (5) The filter cake F is dried, the dried material is extruded into strips, and the strips are calcined to obtain the hydrogenation refining catalyst.

[0017] In the method of the present invention, the nickel salt in the mixed solution A in step (1) is a soluble nickel salt, such as nickel acetate and / or nickel chloride; the molar concentration of Ni, calculated as NiO, is 0.1~1.5 mol / L, preferably 0.4~0.8 mol / L.

[0018] In the method of the present invention, the aluminum source in the mixed solution A in step (1) is aluminum chloride, and the molar concentration of Al is calculated as Al2O3, which is 0.1~1mol / L, preferably 0.2~0.8mol / L.

[0019] In the method of the present invention, in the mixed solution B described in step (1), the molar concentration of sodium molybdate is 0.01~1 mol / L, preferably 0.1~0.7 mol / L. The molar concentration of sodium tungstate is 0.05~1 mol / L, preferably 0.2~0.6 mol / L.

[0020] In the method of the present invention, in the solution C of step (1), the aluminum source is one or more of sodium aluminate, aluminum sulfate, aluminum chloride and aluminum acetate; the molar concentration of Al, calculated as Al2O3, is 0.05~0.5mol / L, preferably 0.1~0.3mol / L.

[0021] In the method of the present invention, step (1) preferably divides solution C into 2 to 8 equal volumes.

[0022] In the method of the present invention, the alkaline precipitant in step (2) is one or more of sodium hydroxide, sodium carbonate, and sodium bicarbonate, and the pH value of the alkaline precipitant is not less than 12.0, preferably 12.5~13.8.

[0023] In the method of the present invention, the coprecipitation reaction in step (2) involves online measurement of the pH of the reaction solution. During the reaction, the pH of the reaction system is maintained in the range of 5.5 to 7.0, preferably 6.0 to 6.5, by controlling the dropping rate of the alkaline precipitant.

[0024] In the method of the present invention, the coprecipitation reaction temperature in step (2) is 30~90℃, preferably 40~70℃; the reaction time is controlled at 30~120 minutes, preferably 40~80 minutes.

[0025] In the method of the present invention, the aging temperature in step (3) is 40-90℃, preferably 60-85℃.

[0026] In the method of the present invention, during the aging process described in step (3), the pH value is first controlled to 11.8~13.8 with sodium aluminate solution, and the aging time is 0.1~0.6 hours; then, after adding 1 part of solution C, the aging pH value is controlled to 8.6~10.2, and the aging time is 0.1~0.6 hours; then the aging pH value is controlled to 5.5~7.0, and the aging time is 0.1~0.6 hours; the above is the complete process of adding 1 part of solution C, and so on until solution C is completely added.

[0027] In the aging process, except for sodium aluminate to control the pH value to 11.8~13.8, the acids and bases used to adjust the pH value can be inorganic salts, inorganic acids and inorganic bases that do not contain aluminum. They can be one or more of hydrochloric acid, acetic acid, sodium hydroxide, sodium carbonate and sodium bicarbonate. The concentration and dosage can be adjusted according to actual needs.

[0028] In the method of the present invention, the aluminum added in step (3) is calculated as Al2O3 and accounts for 5% to 50% of the mass fraction of Al2O3 in the prepared hydrogenation refining catalyst, preferably 10% to 40%.

[0029] In the method of this invention, the humidity of the filter cake conditioning environment in step (4) is greater than 80%; wherein, the temperature of the first conditioning is 28℃~45℃, preferably 35℃~40℃; the conditioning time is 0.4~1.5 hours, preferably 0.6~1.2 hours. The temperature of the second conditioning is 55℃~75℃, preferably 60~68℃; the conditioning time is 0.4~1.5 hours, preferably 0.8~1.2 hours.

[0030] The conditioning process can be carried out in any environment that meets the above conditions, preferably directly in a vacuum filtration device, without moving the filter cake, thus simplifying the process.

[0031] In the method of the present invention, after the first conditioning in step (4), the filter cake base is 20wt%~25wt%; after the second conditioning, the filter cake base is 26wt%~29wt%.

[0032] In the method of the present invention, the deionized water of a certain proportion m in step (4) is m>2.5, preferably 3.5~4.5:1, based on the ratio of the mass of deionized water to the mass of catalyst preparation, and the temperature of the deionized water is 28℃~45℃, preferably consistent with the temperature of the first curing; the deionized water of a certain proportion n is n>0.6, preferably 0.8~2.5:1, based on the ratio of the mass of deionized water to the mass of catalyst preparation, and the temperature of the deionized water is 55℃~75℃, preferably consistent with the temperature of the second curing.

[0033] In the method of the present invention, in step (4) the filtration process I and II: deionized water should not be stirred with the filter cake. Vacuum filtration should be started within 3 minutes after adding deionized water, preferably within 1 minute.

[0034] In the method of the present invention, the drying temperature of the filter cake F in step (5) is 40~90℃, preferably 55~75℃; and the dry basis is controlled to be 43wt%~62wt%, preferably 46wt%~56wt%.

[0035] In the method of the present invention, the roasting temperature in step (5) is 350~560℃, preferably 450~510℃; the roasting time is 2.5~7 hours.

[0036] This invention provides a hydrorefining catalyst, wherein the catalyst components are oxides of tungsten, molybdenum, nickel and aluminum, and the active components, namely oxides of tungsten, molybdenum and nickel, account for 50wt% to 95wt%, preferably 60wt% to 90wt%; the alumina accounts for 5wt% to 50wt%, preferably 10wt% to 40wt%; and the sodium content in the catalyst is ≤0.1%.

[0037] The hydrogenation refining catalyst has a W / Mo molar ratio of 1:8 to 12:1, preferably 1:4 to 6:1, and a (Mo+W) / Ni molar ratio of 1:4 to 10:1, preferably 1:3 to 8:1.

[0038] The hydrorefining catalyst has a specific surface area of ​​260~520 m². 2 / g, pore volume 0.28~0.48mL / g, mechanical strength 16.0~24.0N·mm -1 .

[0039] The pore size distribution of the hydrorefining catalyst is as follows: pores with a diameter of less than 4 nm account for 1% to 9% of the total pore volume; pores with a diameter of 4 to 6 nm account for 5% to 15% of the total pore volume; pores with a diameter of 6 to 10 nm account for 52% to 68% of the total pore volume; pores with a diameter of 10 to 15 nm account for 16% to 30% of the total pore volume; and pores with a diameter of more than 15 nm account for 3% to 12% of the total pore volume.

[0040] Preferably, the catalyst pore size distribution is as follows: pores with a diameter of less than 4 nm account for 2% to 6% of the total pore volume, pores with a diameter of 4 to 6 nm account for 6% to 13% of the total pore volume, pores with a diameter of 6 to 10 nm account for 54% to 64% of the total pore volume, pores with a diameter of 10 to 15 nm account for 22% to 30% of the total pore volume, and pores with a diameter of more than 15 nm account for 3% to 8% of the total pore volume.

[0041] Compared with the prior art, the present invention has the following advantages:

[0042] In this invention, an aluminum-containing solution is added in stages during the aging process, with the pH value fluctuating. This pH fluctuation dissolves the amorphous oxides in the co-precipitated oxide particles. The addition of the aluminum-containing solution modifies the size of the oxide particles. After n pH fluctuations, the growth of the oxide particles is controlled, resulting in more uniform and appropriately sized particles. This improves the dispersion of active metals in the bulk catalyst and increases the proportion of 6-10 nm and 10-15 nm pore sizes in the catalyst, allowing large molecular reactants and products to pass smoothly through the pores, which is beneficial for the hydrogenation activity of the catalyst.

[0043] This invention removes sodium impurities from the product shortly after the aging process. Sodium ions have low adsorption to materials, making them easier to remove and resulting in high impurity removal efficiency. Furthermore, compared to traditional pulping and washing, this method involves two curing processes and vacuum filtration washing, allowing a small amount of water to remove a significant amount of sodium impurities from the filter cake, achieving a sodium content of ≤0.1% in the filter cake. This reduces the number of washing cycles, simplifies the process, and significantly reduces the amount of water used in preparation. Using this method to remove sodium impurities solves the problem of bulk catalysts being difficult to form or having low mechanical strength after forming when the sodium content is too high.

[0044] In the method of this invention, the primary conditioning process precipitates most of the sodium ions from the filter cake, preserving the large pores formed during the pH swing gelation process and preventing them from being occupied by impurity sodium, which would reduce the pore size of the material. In the secondary conditioning process, in addition to precipitating the remaining small portion of sodium ions, the vacancies formed by sodium removal during the primary conditioning process are rapidly diffused outward as water vapor in the filter cake under the higher temperature and humidity provided by the secondary conditioning process. This impacts the pore structure and thus produces a pore-expanding effect on the material. During the temperature-controlled drying of filter cake F in step (5), the same pore-expanding effect is achieved on the material. Furthermore, during the secondary conditioning and temperature-controlled drying of filter cake F, since impurity sodium is removed from the material, sodium chloride crystals will not precipitate and adhere to the internal pores, affecting pore expansion. Therefore, the pore-expanding effect of sodium removal before molding is more significant than that of sodium removal after catalyst molding.

[0045] The hydrorefining catalyst of this invention has a good pore structure, with a large pore volume and a suitable pore size distribution. The active metal is uniformly dispersed, and the mechanical strength is good. It has high performance in hydrodesulfurization, hydrodenitrogenation and aromatic saturation reactions, and is particularly suitable for use in ultra-deep hydrodesulfurization, denitrogenation and aromatic removal reactions of heavy distillate oils. Detailed Implementation

[0046] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. In the catalyst testing and characterization method of the embodiments, the specific surface area and pore size distribution of the support were determined using an ASAP-2405 BET nitrogen adsorption instrument; elemental analysis was performed using an Agilent inductively coupled plasma mass spectrometer (7700 ICP-MS); and the crushing strength of the catalyst was determined using a particle strength tester. Example 1

[0047] Prepare mixed solution A: Nickel chloride (calculated as NiO molar concentration) is 0.60 mol / L, and aluminum chloride (calculated as Al₂O₃ molar concentration) is 0.38 mol / L. Prepare mixed solution B: Sodium tungstate molar concentration is 0.30 mol / L, and sodium molybdate molar concentration is 0.75 mol / L. Prepare solution C: Sodium aluminate molar concentration is 0.10 mol / L (calculated as Al₂O₃ molar concentration). Divide solution C into four equal portions.

[0048] Solution A was used as the base water for the reaction and heated to 70°C. Solution B and sodium hydroxide solution (pH=13.8) were added to the base water in parallel streams to carry out a co-precipitation reaction. The pH value of the reaction was controlled at 6.2~6.3, the reaction temperature was 70°C, and the reaction time was 60 min.

[0049] The aging process was carried out at 83℃. First, the pH value was adjusted to 13.5 with sodium aluminate solution, and the aging time was 0.3 hours. Then, 1 part of solution C was added, and the aging pH value was adjusted to 10.0, with an aging time of 0.4 hours. Next, the aging pH value was adjusted to 6.4, and the aging time was 0.2 hours. The above is the complete addition process of 1 part of solution C. The above process was repeated 4 times to completely add solution C. The amount of Al added during the aging process was calculated as Al2O3, accounting for 25.0% of the final catalyst Al2O3 component, and finally slurry D was obtained.

[0050] Vacuum filtration of slurry D yields a filter cake. The filter cake undergoes a first curing process directly in a vacuum filter, maintaining an ambient humidity of 85%, a curing temperature of 37°C, and a time of 1.0 h. After the first curing, the filter cake has a cake thickness of 22%. Deionized water at a mass ratio of 4:1 (to the catalyst preparation) is added to the top layer of the filter cake at 37°C. After 20 seconds, vacuum filtration is performed until no filtrate drips from the filter cake. A second curing process is then performed, maintaining an ambient humidity of 82%, a curing temperature of 65°C, and a time of 1.2 h. After the second curing, the filter cake has a cake thickness of 28%. Deionized water at a mass ratio of 2:1 (to the catalyst preparation) is added to the top layer of the filter cake at 65°C. After 30 seconds, vacuum filtration is performed until no filtrate drips from the filter cake. Washing is then completed to obtain filter cake F.

[0051] The filter cake F was dried at 72℃ to control the dry basis to 48%; it was extruded into a clover shape and then calcined at 510℃ for 4 hours to obtain the final catalyst a. The main properties are shown in Table 1. Example 2

[0052] Prepare mixed solution A: Nickel chloride (calculated as NiO) is 0.80 mol / L, and aluminum chloride (calculated as Al₂O₃) is 0.15 mol / L. Prepare mixed solution B: Sodium tungstate has a molar concentration of 0.55 mol / L, and sodium molybdate has a molar concentration of 0.70 mol / L. Prepare solution C: Aluminum chloride has a molar concentration of 0.15 mol / L (calculated as Al₂O₃). Divide solution C into 6 equal portions.

[0053] Solution A was used as the reaction substrate and heated to 60°C. Solution B and sodium carbonate solution (pH=13.0) were added to the reaction substrate in parallel streams to carry out a co-precipitation reaction. The reaction pH was controlled at 5.7~5.8, the reaction temperature was 60°C, and the reaction time was 80 min.

[0054] The aging process was carried out at 75℃. First, the pH value was adjusted to 13.0 with sodium aluminate solution, and the aging time was 0.5 hours. Then, 1 part of solution C was added, and the aging pH value was adjusted to 9.6, with an aging time of 0.6 hours. Then, the aging pH value was adjusted to 6.0, and the aging time was 0.5 hours. The above is the complete process of adding 1 part of solution C. The above process was repeated 6 times to completely add solution C. The amount of Al added during the aging process was calculated as Al2O3, accounting for 35.0% of the final catalyst Al2O3 component, and finally slurry D was obtained.

[0055] Vacuum filtration of slurry D yields a filter cake. The filter cake undergoes a first curing process directly in a vacuum filter, maintaining an ambient humidity of 87%, a curing temperature of 31°C, and a time of 1.2 hours. After the first curing, the filter cake has a cake thickness of 23%. Deionized water at a mass ratio of 3.5:1 (to the catalyst preparation) is added to the top of the filter cake at a temperature of 36°C. After 40 seconds, vacuum filtration is performed until no filtrate drips from the filter cake. A second curing process is then performed, maintaining an ambient humidity of 90%, a curing temperature of 60°C, and a time of 0.9 hours. After the second curing, the filter cake has a cake thickness of 26%. Deionized water at a mass ratio of 1.5:1 (to the catalyst preparation) is added to the top of the filter cake at a temperature of 55°C. After 50 seconds, vacuum filtration is performed until no filtrate drips from the filter cake. Washing is then completed to obtain filter cake F.

[0056] The filter cake F was dried at 64℃ to control the dry basis to 44%; it was extruded into a clover shape and then calcined at 490℃ for 4.5h to obtain the final catalyst b. The main properties are shown in Table 1. Example 3

[0057] Prepare mixed solution A: Nickel chloride (calculated as NiO molar concentration) is 0.40 mol / L, and aluminum chloride (calculated as Al₂O₃ molar concentration) is 0.29 mol / L. Prepare mixed solution B: Sodium tungstate molar concentration is 0.40 mol / L, and sodium molybdate molar concentration is 0.50 mol / L. Prepare solution C: Aluminum acetate molar concentration is 0.20 mol / L (calculated as Al₂O₃ molar concentration). Divide solution C into two equal portions.

[0058] Solution A was used as the reaction substrate and heated to 85°C. Solution B and a mixture of sodium bicarbonate and sodium hydroxide (pH=12.5) were added to the reaction substrate in two parallel streams to carry out a co-precipitation reaction. The reaction pH was controlled at 6.4~6.5, the reaction temperature was 85°C, and the reaction time was 100 min.

[0059] The aging process was carried out at 64℃. First, the pH value was adjusted to 12.5 with sodium aluminate solution, and the aging time was 0.6 hours. Then, 1 part of solution C was added, and the aging pH value was adjusted to 9.2, with an aging time of 0.4 hours. Next, the aging pH value was adjusted to 6.9, and the aging time was 0.3 hours. The above is the complete process of adding 1 part of solution C. The above process was repeated twice to completely add solution C. The amount of Al added during the aging process was calculated as Al2O3, accounting for 18.0% of the final catalyst Al2O3 component, and finally slurry D was obtained.

[0060] Vacuum filtration of slurry D yields a filter cake. The filter cake undergoes a first curing process directly in a vacuum filter, maintaining an ambient humidity of 81%, a curing temperature of 40℃, and a time of 0.8 hours. After the first curing, the filter cake has a cake thickness of 25%. Deionized water at a mass ratio of 2.6:1 (to the catalyst preparation) is added to the top layer of the filter cake at 40℃. After 80 seconds, vacuum filtration is performed until no filtrate drips from the filter cake. A second curing process is then performed, maintaining an ambient humidity of 92%, a curing temperature of 69℃, and a time of 0.6 hours. After the second curing, the filter cake has a cake thickness of 27%. Deionized water at a mass ratio of 1.0:1 (to the catalyst preparation) is added to the top layer of the filter cake at 70℃. After 70 seconds, vacuum filtration is performed until no filtrate drips from the filter cake. Washing is then completed to obtain filter cake F.

[0061] The filter cake F was dried at 58℃ to control the dry basis to 53%; it was extruded into a clover shape and then calcined at 470℃ for 6.0 h to obtain the final catalyst c. The main properties are shown in Table 1. Example 4

[0062] Prepare mixed solution A: Nickel chloride (calculated as a molar concentration of NiO) is 0.3 mol / L, and aluminum chloride (calculated as a molar concentration of Al₂O₃) is 0.23 mol / L. Prepare mixed solution B: Sodium tungstate has a molar concentration of 0.25 mol / L, and sodium molybdate has a molar concentration of 0.61 mol / L. Prepare solution C: Sodium aluminate has a molar concentration of 0.25 mol / L (calculated as a molar concentration of Al₂O₃). Divide solution C into 8 equal portions.

[0063] Solution A was used as the base water for the reaction and heated to 40°C. Solution B and a mixture of sodium carbonate and sodium hydroxide (pH=13.4) were added to the base water in parallel streams to carry out a co-precipitation reaction. The pH value of the reaction was controlled at 6.7~6.8, the reaction temperature was 40°C, and the reaction time was 40 min.

[0064] The aging process was carried out at 45℃. First, the pH value was adjusted to 12.0 with sodium aluminate solution, and the aging time was 0.4 hours. Then, 1 part of solution C was added, and the aging pH value was adjusted to 8.7, with an aging time of 0.3 hours. Then, the aging pH value was adjusted to 5.7, and the aging time was 0.2 hours. The above is the complete process of adding 1 part of solution C. The above process was repeated 8 times to completely add solution C. The amount of Al added during the aging process was calculated as Al2O3, accounting for 48.0% of the final catalyst Al2O3 component, and finally slurry D was obtained.

[0065] Vacuum filtration of slurry D yields a filter cake. The filter cake undergoes a first curing process directly in a vacuum filter, maintaining a humidity of 92%, a temperature of 43°C, and a time of 0.6 hours. After the first curing, the filter cake has a cake thickness of 24%. Deionized water at a mass ratio of 5:1 (to the catalyst preparation) is added to the top of the filter cake at 30°C. After 120 seconds, vacuum filtration is performed until no filtrate drips from the filter cake. A second curing process is then performed, maintaining a humidity of 86% and a temperature of 72°C for 0.5 hours. After the second curing, the filter cake has a cake thickness of 28%. Deionized water at a mass ratio of 2.8:1 (to the catalyst preparation) is added to the top of the filter cake at 75°C. After 90 seconds, vacuum filtration is performed until no filtrate drips from the filter cake. Washing is then completed to obtain filter cake F.

[0066] The filter cake F was dried at 85℃, with the dry basis controlled at 60%; it was extruded into a clover shape and then calcined at 500℃ for 2.5 h to obtain the final catalyst d. The main properties are shown in Table 1. Example 5

[0067] Prepare mixed solution A: Nickel chloride (calculated as NiO molar concentration) is 0.50 mol / L, and aluminum chloride (calculated as Al₂O₃ molar concentration) is 0.36 mol / L. Prepare mixed solution B: Sodium tungstate molar concentration is 0.19 mol / L, and sodium molybdate molar concentration is 0.35 mol / L. Prepare solution C: Aluminum sulfate (calculated as Al₂O₃ molar concentration) is 0.30 mol / L. Divide solution C into 5 equal portions.

[0068] Solution A was used as the base water for the reaction and heated to 50°C. Solution B and sodium hydroxide solution (pH=12.8) were added to the base water in parallel streams to carry out a co-precipitation reaction. The pH value of the reaction was controlled at 6.3~6.4, the reaction temperature was 50°C, and the reaction time was 70 min.

[0069] The aging process was carried out at 55℃. First, the pH value was adjusted to 13.2 with sodium aluminate solution, and the aging time was 0.2 hours. Then, 1 part of solution C was added, and the aging pH value was adjusted to 9.0, with an aging time of 0.5 hours. Next, the aging pH value was adjusted to 6.6, and the aging time was 0.6 hours. The above is the complete process of adding 1 part of solution C. The above process was repeated 5 times to completely add solution C. The amount of Al added during the aging process was calculated as Al2O3, accounting for 33.0% of the final catalyst Al2O3 component, and finally slurry D was obtained.

[0070] Vacuum filtration of slurry D yields a filter cake. The filter cake undergoes a first curing process in an insulated chamber, maintaining 95% humidity and 34°C for 0.5 hours. After the first curing, the filter cake has a cake thickness of 21%. The filter cake is then placed flat and seamlessly on the filter cloth of a vacuum filter. Deionized water at a mass ratio of 4.5:1 (to the catalyst preparation) is added to the top of the filter cake at 45°C. After 160 seconds, vacuum filtration is performed until no filtrate drips from the filter cake. A second curing process is then performed, maintaining 96% humidity and 58°C for 0.7 hours. After the second curing, the filter cake has a cake thickness of 26%. Deionized water at a mass ratio of 3.0:1 (to the catalyst preparation) is added to the top of the filter cake at 60°C. After 40 seconds, vacuum filtration is performed until no filtrate drips from the filter cake. Washing is then completed to obtain filter cake F.

[0071] The filter cake F was dried at 45℃ to control the dry basis to 56%; it was extruded into a clover shape and then calcined at 480℃ for 5.0 h to obtain the final catalyst e. The main properties are shown in Table 1.

[0072] Comparative Example 1

[0073] Prepare mixed solution A: Nickel chloride (calculated as NiO molar concentration) is 0.60 mol / L, and aluminum chloride (calculated as Al2O3 molar concentration) is 0.51 mol / L. Prepare mixed solution B: Sodium tungstate molar concentration is 0.30 mol / L, and sodium molybdate molar concentration is 0.75 mol / L.

[0074] Solution A was used as the base water for the reaction and heated to 70°C. Solution B and sodium hydroxide solution (pH=13.8) were added to the base water in parallel streams to carry out a co-precipitation reaction. The pH value of the reaction was controlled at 6.2~6.3, the reaction temperature was 70°C, and the reaction time was 60 min.

[0075] The aging process was carried out at an aging temperature of 83℃, a pH value of 6.2-6.3 during aging, and an aging time of 0.9 hours, ultimately yielding slurry D.

[0076] Vacuum filtration of slurry D yields a filter cake. The filter cake undergoes a first curing process directly in a vacuum filter, maintaining an ambient humidity of 85%, a curing temperature of 37°C, and a time of 1.0 h. After the first curing, the filter cake has a cake thickness of 22%. Deionized water at a mass ratio of 4:1 (to the catalyst preparation) is added to the top layer of the filter cake at 37°C. After 20 seconds, vacuum filtration is performed until no filtrate drips from the filter cake. A second curing process is then performed, maintaining an ambient humidity of 82%, a curing temperature of 65°C, and a time of 1.2 h. After the second curing, the filter cake has a cake thickness of 28%. Deionized water at a mass ratio of 2:1 (to the catalyst preparation) is added to the top layer of the filter cake at 65°C. After 30 seconds, vacuum filtration is performed until no filtrate drips from the filter cake. Washing is then completed to obtain filter cake F.

[0077] The filter cake F was dried at 72℃ to control the dry basis to 48%; it was extruded into a clover shape and then calcined at 510℃ for 4 hours to obtain the final catalyst f. The main properties are shown in Table 1.

[0078] Comparative Example 2

[0079] The other steps in this embodiment are the same as in embodiment 1. The difference is that the impurity removal process in step (4) is not performed in this comparative example after the aging treatment.

[0080] The catalyst g was finally obtained, and its main properties are shown in Table 1.

[0081] Comparative Example 3

[0082] The other steps in this embodiment are the same as in embodiment 1. The difference is that in the impurity removal process in step (4) of this comparative example, the first and second conditioning are not performed, and the deionized water filtration process I and II are performed directly twice.

[0083] The catalyst h was finally obtained, and its main properties are shown in Table 1.

[0084] Comparative Example 4

[0085] The other steps in this embodiment are the same as in embodiment 1. The difference is that in the impurity removal process in step (4) of this comparative example, the humidity of the secondary curing environment is 50% and the curing temperature is 30℃.

[0086] The final catalyst i was obtained, and its main properties are shown in Table 1.

[0087] Comparative Example 5

[0088] Following the method disclosed in CN114471594A, with the catalyst composition referring to Example 1, catalyst j was prepared. The specific process is as follows: A mixed solution P containing nickel chloride, aluminum chloride solution, citric acid, and propylene glycol was prepared. The mass concentration of Ni (calculated as NiO) in the mixed solution was 26 g / L, the mass concentration of Al (calculated as Al2O3) was 30 g / L, the molar ratio of citric acid to propylene glycol was 1.0, and the molar ratio of the total moles of citric acid and propylene glycol to Ni was 1.2. 500 mL of deionized water was added to the reaction vessel as the reaction base water. A 12 wt% sodium hydroxide solution, sodium tungstate and sodium molybdate solution (W calculated as WO3 with a mass concentration of 20 g / L, Mo calculated as MoO3 with a mass concentration of 30 g / L) and the mixed solution P were added to the reaction vessel in parallel flow. The gelation reaction temperature was 60 °C, the reaction pH was 7.6, and the gelation time was 60 minutes, resulting in a precipitate slurry.

[0089] The slurry was aged at 72℃, with an aging pH of 7.8, for 2 hours. The slurry was then filtered, and the resulting filter cake was dried at 80℃ for 10 hours, then rolled and extruded into strips.

[0090] Sodium impurity removal was performed on the molded strips: After curing at 85℃ for 48 hours, the temperature was lowered to 28℃ and curing continued for 30 hours. The strips were then washed twice with deionized water at a mass ratio of 5:1 (deionized water to catalyst), and then dried and calcined. The main properties of catalyst j are shown in Table 1. Example 6

[0091] This embodiment presents activity evaluation experiments on catalysts prepared in different embodiments and comparative examples of the present invention. Catalysts a, b, and c of the present invention and comparative catalysts f, h, i, and j were used. Catalyst g was not evaluated due to its low mechanical strength, falling outside the performance index range. The evaluation experiments were conducted on a 200 mL small-scale hydrogenation apparatus.

[0092] The evaluation conditions were: total reaction pressure 6.8 MPa, hydrogen-to-oil volume ratio 500:1, and volume hourly space velocity 1.5 h⁻¹. -1 The reaction temperature was 365℃. The main properties of the raw materials used for evaluation are shown in Table 2. Table 3 lists the evaluation results of the catalyst.

[0093] Table 3 shows that catalysts a and b prepared using the present invention exhibit superior hydrodesulfurization, hydrodenitrogenation, and aromatic saturation performance compared to comparative example j. The bulk catalysts prepared by the method of the present invention show significantly improved pore structure, larger pore volume and specific surface area, and a shift in pore distribution towards larger pores, resulting in a well-distributed pore structure and thus significantly enhanced hydrogenation activity. Catalyst a demonstrates superior hydrogenation activity compared to comparative example f, indicating that the pH fluctuation and gelation during the aging process in the present invention effectively adjusts the pore structure of the catalyst, and the shift in pore distribution towards larger pores promotes hydrogenation activity. Catalyst a also demonstrates superior hydrogenation activity compared to comparative examples h and i, indicating that the subsequent sodium removal treatment in the present invention not only effectively removes sodium from the catalyst but also that the pore-expanding effect of the secondary conditioning promotes hydrogenation activity.

[0094] Table 1. Composition and properties of catalysts prepared in the examples and comparative examples

[0095] Catalyst number a b c d e f g h i j Catalyst composition <![CDATA[MoO3,wt%]]> 42 32 24 28 14 42 42 42 42 42 <![CDATA[WO3,wt%]]> 28 40 30 18 12 28 28 28 28 28 NiO, wt% 14 20 21 18 30 14 14 14 14 14 <![CDATA[Al2O3,wt%]]> margin margin margin margin margin margin margin margin margin margin Na, ppm 144 253 421 219 376 169 86463 2312 635 1577 <![CDATA[Specific surface area, m 2 / g]]> 407 392 412 417 431 401 115 396 402 382 Pore ​​volume, mL / g 0.458 0.426 0.440 0.432 0.469 0.423 0.122 0.439 0.453 0.405 Pore ​​distribution, % <4nm 4.23 8.20 6.14 6.28 3.17 7.31 25.59 6.17 6.16 8.64 4nm~6nm 10.62 14.92 12.83 14.48 8.25 16.59 53.87 13.31 12.29 18.72 6nm~10nm 57.58 52.76 54.60 53.39 55.32 52.72 10.43 53.89 55.61 49.34 10nm~15nm 22.32 20.48 22.19 21.70 25.90 18.24 8.91 21.62 21.89 17.88 >15nm 5.25 3.64 4.24 4.15 7.36 5.14 1.20 5.01 4.05 5.42 Mechanical strength, N / mm 19.4 17.7 21.4 21.9 20.3 19.8 3.7 19.0 20.2 13.5

[0096] Table 2 Properties of Crude Oil

[0097] crude oil Blended diesel Straight diesel / coke diesel / catalytic diesel, % 32 / 37 / 31 Secondary processed diesel fuel, % 68 <![CDATA[Density (20 °C) / g•cm -3 > 0.8763 Distillation range / ℃ (IBP~FBP) 149～372 Sulfur / µg•g-1 14203 Nitrogen µg•g-1 846 Aromatics, % 45.9 Polycyclic aromatic hydrocarbons, % 24.1 Cetane index 32.5

[0098] Table 3. Catalyst evaluation test results

[0099] Catalyst number a b f h i j <![CDATA[Generated oil density (20 °C), g / cm 3 > 0.8535 0.8514 0.8546 0.8553 0.8540 0.8559 S, µg / g 7.9 5.2 10.7 13.2 9.6 14.1 N, µg / g 5.7 3.4 6.8 7.4 6.1 7.8 Aromatics, wt% 27.5 27.0 28.1 28.5 27.7 28.8 Polycyclic aromatic hydrocarbons, wt% 4.9 4.4 5.6 6.3 5.1 6.5 cetane number 41.5 42.1 40.8 40.6 41.2 40.2

Claims

1. A method for preparing a hydrorefining catalyst, characterized in that... The following are included: (1) Prepare a mixed solution A containing Al components and nickel salts; prepare a mixed solution B containing sodium tungstate and sodium molybdate; prepare a solution C containing Al components; (2) Use mixed solution A as the bottom water for co-precipitation reaction. Under high-speed stirring conditions, add mixed solution B and alkaline precipitant to mixed solution A in a co-flow dropwise manner to obtain slurry D; (3) Age slurry D. According to the number of times it is added during the aging process, add solution C in equal volumes of 2 to 8 parts to obtain slurry E; (4) Vacuum filter slurry E to obtain filter cake. The filter cake is cured once; after curing, add a certain proportion of m deionized water to the filter cake and perform vacuum filtration process I; continue to cure the filter cake a second time, add a certain proportion of n deionized water to the filter cake and perform vacuum filtration process II to obtain filter cake F; (5) Filter cake F The material is dried, extruded into strips, and calcined to obtain a hydrogenation refining catalyst. In the aging process described in step (3), the pH value is first controlled to 11.8~13.8 with sodium aluminate solution, and the aging time is 0.1~0.6 hours. Then, 1 part of solution C is added, and the aging pH value is controlled to 8.6~10.2, and the aging time is 0.1~0.6 hours. Then, the aging pH value is controlled to 5.5~7.0, and the aging time is 0.1~0.6 hours. The above process is repeated until all parts of solution C are completely added. In step (4), the humidity of the filter cake in the curing environment is greater than 80%. The first curing temperature is 28℃~45℃, and the curing time is 0.4~1.5 hours. The second curing temperature is 55℃~75℃, and the curing time is 0.4~1.5 hours.

2. The method according to claim 1, characterized in that: In step (1), the nickel salt in the mixed solution A is a soluble nickel salt, and the molar concentration of Ni is calculated as NiO, which is 0.1~1.5 mol / L.

3. The method according to claim 1, characterized in that: In step (1), the mixed solution A contains aluminum chloride as the Al component, and the molar concentration of Al is 0.1~1 mol / L, calculated as Al2O3.

4. The method according to claim 1, characterized in that: In the mixed solution B described in step (1), the molar concentration of sodium molybdate is 0.01~1 mol / L and the molar concentration of sodium tungstate is 0.05~1 mol / L.

5. The method according to claim 1, characterized in that: In step (1), the solution C contains Al components, which are one or more of sodium aluminate, aluminum sulfate, aluminum chloride and aluminum acetate; the molar concentration of Al is calculated as Al2O3 and is 0.05~0.5mol / L.

6. The method according to claim 1, characterized in that: The alkaline precipitant in step (2) is one or more of sodium hydroxide, sodium carbonate, and sodium bicarbonate, and the pH value of the alkaline precipitant is not less than 12.

0.

7. The method according to claim 1, characterized in that: In step (2), the pH of the reaction solution is measured online. During the reaction, the pH of the reaction system is maintained in the range of 5.5 to 7.0 by controlling the dropping rate of the alkaline precipitant.

8. The method according to claim 1, characterized in that: The coprecipitation reaction temperature in step (2) is 30~90℃, and the reaction time is controlled at 30~120 minutes.

9. The method according to claim 1, characterized in that: The aging temperature in step (3) is 40 to 90°C.

10. The method according to claim 1, characterized in that: During the aging process, except for sodium aluminate to control the pH value to 11.8~13.8, 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: The aluminum added in step (3), calculated as Al2O3, accounts for 5% to 50% of the mass fraction of Al2O3 in the prepared hydrorefining catalyst.

12. The method according to claim 1, characterized in that: In step (4), the temperature for the first health-preserving session is 35℃~40℃ and the duration is 0.6~1.2 hours. The temperature for the second health-preserving session is 60~68℃ and the duration is 0.8~1.2 hours.

13. The method according to claim 1, characterized in that: After the first conditioning treatment in step (4), the filter cake base is 20wt%~25wt%; after the second conditioning treatment, the filter cake base is 26wt%~29wt%.

14. The method according to claim 1, characterized in that: In step (4), the deionized water of a certain proportion m is calculated as the ratio of the mass of deionized water to the mass of catalyst preparation, where m > 2.5 and the temperature of the deionized water is 28℃ to 45℃; the deionized water of a certain proportion n is calculated as the ratio of the mass of deionized water to the mass of catalyst preparation, where n > 0.6 and the temperature of the deionized water is 55℃ to 75℃.

15. The method according to claim 1, characterized in that: In step (4), the deionized water of a certain proportion m is 3.5 to 4.5:1 in terms of the ratio of the mass of deionized water to the mass of catalyst preparation, and the temperature of the deionized water is consistent with the temperature of the first curing. The deionized water of a certain proportion n is 0.8 to 2.5:1 in terms of the ratio of the mass of deionized water to the mass of catalyst preparation, and the temperature of the deionized water is consistent with the temperature of the second curing.

16. The method according to claim 1, characterized in that: Step (4) describes the filtration process I and II: Deionized water is not stirred with the filter cake. Vacuum filtration begins within 3 minutes after adding deionized water.

17. The method according to claim 1, characterized in that: The drying temperature of the filter cake F in step (5) is 40~90°C, and the dry basis is controlled to be 43wt%~62wt%.

18. The method according to claim 1, characterized in that: The roasting temperature in step (5) is 350~560℃ and the roasting time is 2.5~7 hours.

19. A hydrorefining catalyst prepared by the method according to any one of claims 1 to 18, characterized in that: The catalyst components are oxides of tungsten, molybdenum, nickel, and aluminum, wherein the active components of tungsten, molybdenum, and nickel oxide account for 50wt%~95wt%, and aluminum oxide accounts for 5wt%~50wt%; the sodium content in the catalyst is ≤0.1%.

20. The hydrorefining catalyst according to claim 19, characterized in that: The molar ratio of W / Mo in the hydrorefining catalyst is 1:8~12:1, and the molar ratio of (Mo+W) / Ni is 1:4~10:

1.

21. The hydrorefining catalyst according to claim 19, characterized in that: Hydrorefining catalysts have a specific surface area of ​​260~520 m². 2 / g, pore volume 0.28~0.48mL / g, mechanical strength 16.0~24.0N·mm -1 .

22. The hydrorefining catalyst according to claim 19, characterized in that: The pore size distribution of the hydrorefining catalyst is as follows: pores with a diameter of less than 4 nm account for 1% to 9% of the total pore volume; pores with a diameter of 4 to 6 nm account for 5% to 15% of the total pore volume; pores with a diameter of 6 to 10 nm account for 52% to 68% of the total pore volume; pores with a diameter of 10 to 15 nm account for 16% to 30% of the total pore volume; and pores with a diameter of more than 15 nm account for 3% to 12% of the total pore volume.

23. The hydrorefining catalyst according to claim 19 or 22, characterized in that: The pore size distribution of the hydrorefining catalyst is as follows: pores with a diameter of less than 4 nm account for 2% to 6% of the total pore volume; pores with a diameter of 4 to 6 nm account for 6% to 13% of the total pore volume; pores with a diameter of 6 to 10 nm account for 54% to 64% of the total pore volume; pores with a diameter of 10 to 15 nm account for 22% to 30% of the total pore volume; and pores with a diameter of more than 15 nm account for 3% to 8% of the total pore volume.