A hydrocracking catalyst carrier, a preparation method thereof and a hydrocracking catalyst

Abstract

The present application belongs to the field of petrochemical and fine chemical industry, and particularly relates to a hydrocracking catalyst carrier, a preparation method thereof and a hydrocracking catalyst. The present application kneads pseudo-boehmite containing boron and silicon, a molecular sieve and a forming aid, forms, dries, and roasts to obtain a hydrocracking catalyst carrier; introduces active metals on the prepared hydrocracking catalyst carrier, and after drying and roasting, a final hydrocracking catalyst is prepared. The hydrocracking catalyst prepared by using the hydrocracking catalyst carrier of the present application has the advantages of high strength and high content of large pores, and is used for flexible production of high-quality heavy naphtha, aviation kerosene, diesel and hydrocracking tail oil, and has excellent activity and selectivity performance of target products.

Description

Technical Field

[0001] This invention belongs to the fields of petrochemicals and fine chemicals, specifically relating to a hydrocracking catalyst support, its preparation method, and a hydrocracking catalyst. Background Technology

[0002] Hydrocracking technology, as one of the most important means of lightening heavy oil, is becoming increasingly important against the backdrop of the gradual deterioration of global crude oil resources and the continuous increase in the proportion of heavy crude oil. Hydrocracking technology is highly adaptable to crude oil, processing heavy fractions from both low-quality crude oil with high sulfur and nitrogen content and crude oil with different bases such as paraffinic and naphthenic. Hydrocracking plays a crucial bridging role between refining and chemical industries. It provides a means to improve oil quality and yield in the refining sector and provides high-quality feedstock for the chemical sector, thereby achieving efficient and comprehensive utilization of crude oil resources in both refining and chemical fields.

[0003] The core of hydrocracking is the hydrocracking catalyst. The hydrogenation function is provided by the metallic active component: common hydrogenation functional components include noble metals (such as platinum and palladium) and non-noble metals (such as nickel, molybdenum, and tungsten). These metals exist on the catalyst surface in a highly dispersed form. The cracking function is provided by the acidic support, common acidic supports include amorphous silica-alumina and molecular sieves (such as Y-type and β-type). These supports possess acidic centers. During the hydrocracking reaction, the hydrogenation and cracking functions work together to adjust product distribution and quality.

[0004] CN 116262882 B discloses a hydrocracking method for producing naphtha, light ethylene feedstock, and high-quality tail oil. The method includes: mixing feedstock oil with hydrogen and then reacting it in a hydrorefining reaction zone to obtain a portion of the refined effluent, which enters hydrocracking reaction zone I. The reaction effluent is then separated and fractionated in fractionating tower I into light naphtha fraction, heavy naphtha fraction, middle distillate oil, and tail oil I fraction. Another portion of the refined effluent, middle distillate oil, and hydrogen are mixed and then enter hydrocracking reaction zone II for further reaction. The reaction effluent is sent to fractionating tower II for further separation, and the top product is sent to fractionating tower I for further separation. The bottom product is tail oil fraction II. While this method can convert a large proportion of feedstock oil into chemical feedstocks, the process is complex, requires significant investment, and is difficult to operate.

[0005] CN 116024007 B discloses a hydrocracking method for low-quality feedstock oil. The method includes the following steps: (1) the low-quality feedstock oil is reacted in a first hydrorefining reaction zone, and the nitrogen content of the liquid effluent after the hydrorefining reaction is controlled to be 300-1450 mg / kg, preferably 500-1300 mg / kg; (2) the stream after the reaction in step (1) is separated to obtain gaseous and liquid products; (3) the liquid product obtained in step (2) enters a second hydrorefining reaction zone for reaction; (4) the stream obtained in step (3) reacts with the gaseous product obtained in step (2) under the action of a hydrocracking catalyst, and the stream after the reaction is separated to obtain naphtha, diesel, and tail oil. This method can reasonably match the refining section and the cracking section to directly process low-quality feedstock oil, but the process flow is complex, the selectivity of the target product has room for further improvement, and the hydrogen consumption is high.

[0006] In summary, in the existing technologies, it is difficult to produce chemical feedstocks through high-selectivity hydrocracking of inferior raw materials. The process is complex and the selectivity of the target product is poor. The essential core need is to develop high-selectivity hydrocracking catalysts. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a hydrocracking catalyst support, its preparation method, and a hydrocracking catalyst. The hydrocracking catalyst prepared using this invention's hydrocracking catalyst support has advantages such as high strength and high macropore content, making it suitable for the flexible production of high-quality heavy naphtha, jet fuel, diesel oil, and hydrocracking tail oil, exhibiting excellent activity and selectivity for the target products.

[0008] To achieve the above objectives, the technical solution of the present invention is as follows:

[0009] This invention provides a method for preparing a hydrocracking catalyst support, the method comprising the following steps:

[0010] (1) Place sodium aluminate solution in a gelling reactor, add boron and silicon precursor mixed solution and mix evenly, introduce a mixed gas of air and CO2 to control the pH value of the slurry, stop introducing the mixed gas when the pH value of the slurry reaches the endpoint pH value, filter the slurry, wash and dry it to obtain boron and silicon pseudoboehmite.

[0011] (2) Boron- and silicon-containing pseudoboehmite, molecular sieve, and molding aid are mixed, shaped, dried in an alkaline gas atmosphere, with the pH controlled at 7-12, and then calcined to obtain a hydrocracking catalyst support.

[0012] In the above technical solution, further, in step (1), the boron- and silicon precursor mixed solution is a mixed solution of boron-based surfactant and silicon surfactant;

[0013] The boron-based surfactant is one or more of the following: glycerol ester borate surfactants, borate alkyl alcohol amide ester surfactants, and borate amphoteric surfactants.

[0014] The silicon surfactant is one or more of the following: siloxane surfactant, polysiloxane or carbosilane surfactant and polysilane surfactant;

[0015] In the boron- and silicon precursor mixed solution, the concentration of boron as B2O3 is 10 g to 40 g / L, preferably 10 to 20 g / L, and the concentration of silicon as SiO2 is 20 to 180 g / L, preferably 50 to 170 g / L.

[0016] The sodium aluminate solution has a concentration of 80–150 g / L, preferably 85–140 g / L, based on Al2O3, and a caustic ratio of 1.10–1.40. The sodium aluminate solution is prepared using conventional methods, and the preferred preparation process is as follows: aluminum hydroxide and sodium hydroxide are reacted at high temperature to prepare the solution.

[0017] The volume of the boron- and silicon precursor mixed solution is 1 / 10 to 2 / 5 of the volume of the sodium aluminate solution.

[0018] In the above technical solution, further, in step (1), the mixing process is carried out by introducing air into the lower part of the reactor for stirring, wherein the air flow rate is 1.0 to 2.0 m / s. 3 / h;

[0019] The final pH value of the slurry was 9.5–11.5;

[0020] The volume fraction of CO2 in the air-CO2 mixture is 30%–60%; the flow rate of the mixed gas introduced per cubic meter of sodium aluminate solution is 1.5–2.5 m³ / s. 3 / h, preferably 1.7~2.3m 3 / h.

[0021] In the above technical solution, further, in step (1), the washing is done with deionized water until neutral; the drying conditions are as follows: the drying temperature is 100℃~130℃, preferably 110℃~120℃, and the drying time is 2~8 hours, preferably 4~6 hours.

[0022] The pseudoboehmite obtained in step (1) of this invention has the following properties: pore volume 0.95~1.20mL / g, specific surface area 330~450m. 2 / g, the pore volume of pores with a diameter <6nm accounts for <6% of the total pore volume, and the pore volume of pores with a diameter of 6~15nm accounts for 45%~65% of the total pore volume;

[0023] Based on the properties of the dry basis, the boron content is 1.0% to 5.0% as B2O3, and the silicon content is 1.0% to 20.0% as SiO2.

[0024] In the above technical solution, further, in step (2), the molecular sieve is a molecular sieve that provides acidity for the hydrocracking reaction, and it is particularly suitable to select modified molecular sieves with high Brønsted acid content, wherein the Brønsted acid content is 0.05-3 mmol / g, preferably 1.0-2.5 mmol / g, and at least one of Y-type molecular sieve, β-type molecular sieve, and ZSM-5 type molecular sieve can be selected according to knowledge in the art; the molecular sieve is preferably a Y-type molecular sieve, which can be prepared or commercially available according to knowledge in the art. The Y-type molecular sieve generally possesses the following properties: an average grain diameter of 2.0–5.5 μm, preferably 3.0–4.5 μm; a relative crystallinity of 110%–160%; a SiO2 / Al2O3 molar ratio of 60–130; a cell parameter of 2.424–2.436 nm, preferably 2.426–2.435 nm; pores with a diameter of 3–7 nm occupying 70%–95% of the total pore volume, preferably 75%–90%; and a pore volume of 0.35 cm³. 3 / g~0.50cm 3 / g, specific surface area is 800~980m² 2 / g, total acidity in infrared radiation 0.05~6mmol / g.

[0025] The alkaline gas is one or a combination of ammonia, phosphine, and hydrazine. For example, if ammonia is used, it can be derived from the thermal decomposition of ammonia water, urea, ammonium bicarbonate, etc.

[0026] The drying process is as follows: for 80% to 90% of the time before drying, the pH range of the alkaline gas atmosphere is controlled to be 7 to 8 by adjusting the concentration of alkaline gas; for 10% to 20% of the time after drying, the pH range of the alkaline gas atmosphere is controlled to be 9 to 12, preferably 9 to 10, by adjusting the concentration of alkaline gas; the drying temperature is 50 to 160°C, preferably 85 to 120°C, and the drying time is 1 to 15 hours.

[0027] The roasting temperature is 450–650℃, preferably 500–580℃, and the roasting time is 1–10 hours.

[0028] In the above technical solution, further, in step (2), the molding aid is selected from at least one of pectinic acid, extrusion aid, and adhesive;

[0029] The pectic acid is one or a mixture of citric acid and nitric acid, preferably a mixture of citric acid and nitric acid;

[0030] The adhesive is small-pore alumina;

[0031] The extrusion aid is one or more of starch, polyvinyl alcohol, polyacrylamide, methylcellulose, and guar gum powder.

[0032] Another aspect of the present invention provides a hydrocracking catalyst support prepared by the above-mentioned preparation method, wherein the support comprises a molecular sieve and boron- and silica-containing pseudoboehmite;

[0033] Based on the weight of the carrier, the carrier contains 40% to 90% boron and silicoboehmite, preferably 55% to 75%, and the molecular sieve content is 10% to 60%, preferably 25% to 45%.

[0034] The carrier has the following properties: a specific surface area of ​​210–480 m². 2 / g, the pore volume is 0.35~0.75ml / g, and the pore volume with a diameter >15nm accounts for 20%~30% of the total pore volume;

[0035] Based on the properties of the dry basis, the support contains 1.0% to 5.0% boron (B2O3) and 1.0% to 20.0% silicon (SiO2).

[0036] The shape of the hydrocracking catalyst support can be formed according to common molding methods in the field, and depending on technical requirements, it can be toothed spherical, clover-shaped, four-leaf clover-shaped, or cylindrical strip, etc.

[0037] The present invention also provides a hydrocracking catalyst, which is prepared by impregnating the above-mentioned hydrocracking catalyst support with a solution containing an active metal, followed by drying and calcination.

[0038] In the above technical solution, the active metal is a Group VIII B metal or a Group VIB metal, wherein the Group VIII B metal is one or two of Co and Ni, and the Group VIB metal is one or two of W and Mo.

[0039] Based on the weight of the catalyst, the content of Group VIII B metals as oxides is 2 wt% to 16 wt%, preferably 5 wt% to 11 wt%, the content of Group VIB metals as oxides is 10 wt% to 35 wt%, preferably 15 wt% to 30 wt%, and the content of the hydrocracking catalyst support is 50 wt% to 80 wt%, preferably 65 wt% to 75 wt%.

[0040] In the above technical solution, the impregnation method is further selected from one of equal volume impregnation, supersaturated impregnation, step impregnation, and co-impregnation, with equal volume co-impregnation being preferred;

[0041] The drying temperature is 50–200℃, preferably 90–160℃, and the drying time is 1–10h, preferably 1–5h.

[0042] The roasting temperature is 350–600℃, preferably 380–500℃, and the roasting time is 1–10h, preferably 1–5h.

[0043] In the above technical solution, the catalyst further includes an additive, which is one or more oxides of P, B, Ti, and Zr. The content of the additive, based on the weight of the catalyst, is less than 6% of the weight of the hydrocracking catalyst, preferably 0.1% to 5.0%.

[0044] The beneficial effects of this invention are as follows:

[0045] (1) The preparation method of boron- and silicon-containing boehmite of the present invention utilizes the hydrophilic groups of surfactants to couple with the crystal grains formed in the reaction, which overcomes the problem that boron is adsorbed on the crystal grains in traditional boron additive sources (such as boric acid, borax, etc.), and is easily lost in the subsequent water washing process, causing environmental pollution and crop poisoning. At the same time, it also overcomes the bottleneck that traditional silicon additive sources (such as sodium carbosilicate, silica gel, etc.) exist in the slurry in the form of micelles, resulting in uneven dispersion of silicon in the boehmite dry glue. It also enhances the bonding force between boehmite particles, thereby improving its mechanical strength.

[0046] (2) Because surfactants can reduce the surface tension of a solution, molecules move more slowly and are closer together in a liquid. Therefore, the attraction between molecules dominates the surface tension. Adding surfactants to a dilute sodium aluminate solution increases the surface area while keeping the molecular volume constant. This results in an increase in the distance between molecules and a decrease in the intermolecular interaction force. Therefore, the boehmite dry adhesive prepared by this invention has a large pore volume and pore size. At the same time, because surfactants have dispersing and solubilizing effects, this invention can still prepare boron- and silicon-containing boehmite with large pore volume and large pore size even at higher raw material concentrations, thus improving production efficiency.

[0047] (3) The boron- and silicon-containing pseudoboehmite of the present invention adopts a carbonization method to form a gel, which does not require excessive requirements on the gelation environment (such as temperature). After the gelation is completed, there is no need for aging, which shortens the production process. The preparation method of this hydrocracking catalyst has a short process, simple process, easy operation and low cost.

[0048] (4) The hydrocracking catalyst of the present invention has the advantages of high strength and high macropore content. The overall pore structure of the catalyst has been optimized, which is more conducive to the dispersion of active metals and the utilization rate of active metals. It solves the technical bottleneck of stress concentration points generated inside the catalyst due to active metal agglomeration, which reduces the overall strength of the catalyst. The increased macropore content is conducive to the diffusion of macromolecular reactants and also conducive to the deposition of impurities during hydrocracking, improving the catalyst's resistance to carbon deposition. This can enhance the activity stability of the catalyst and make it suitable for the flexible production of high-quality heavy naphtha, jet fuel, diesel and hydrocracking tail oil. It has excellent activity and selectivity for target products. Detailed Implementation

[0049] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0050] The technical features of the present invention are further illustrated below through embodiments, but are not limited to these embodiments. Unless otherwise specified, the materials used in the embodiments of the present invention can be obtained commercially or prepared according to conventional methods known to those skilled in the art.

[0051] The following pore volume and surface area were analyzed using the low-temperature nitrogen adsorption method.

[0052] Example 1

[0053] Preparation of hydrocracking catalyst support:

[0054] Prepare a concentrated sodium aluminate solution with a caustic ratio of 1.15 and a concentration of 351 g / L (calculated as Al2O3) by mixing industrial grade 1 aluminum hydroxide powder and industrial grade 1 sodium hydroxide.

[0055] Take 285L of the solution and add it to the gelation reactor. Dilute it with deionized water to 1000L to prepare a dilute sodium aluminate solution with a concentration of 100g / L (calculated as Al2O3). Add 140L of a mixed solution of borate alkyl alcohol amide ester and trimethylsiloxane. The concentration of boron in the mixed solution is 20g / L (calculated as B2O3) and the concentration of silicon is 68g / L (calculated as SiO2).

[0056] Air is introduced from the bottom of the reactor for stirring, and the air flow rate is controlled at 1.8 m / s. 3 After thorough mixing, a mixture of air and CO2 is introduced at a flow rate of 1.85 m³ / h. 3 / h, where the volume fraction of CO2 is 55%, when the pH value of the slurry in the reactor drops to 10.5, the mixed gas is turned off and the reaction is stopped. The slurry is filtered to obtain a filter cake, which is washed with deionized water at 65℃ until neutral, and dried at 120℃ for 3 hours to obtain boron- and silicon-containing pseudoboehmite.

[0057] The prepared boron- and silica-containing pseudoboehmite (69g), Y-type molecular sieve (purchased from Shandong Yutai Chemical Co., Ltd., Na2O content ≤0.15m%, silica-alumina molar ratio 10.2, cell constant 2.450nm, relative crystallinity ≥95%, dry basis 70±5m%), and guar gum powder (1g) were dry-mixed and rolled in a roller for 20 minutes. Then, 12.8g of dilute nitric acid (4.0g HNO3 / 100cm³) was added. 3 The mixture was kneaded, extruded into strips, and then dried at 120°C in an alkaline atmosphere containing ammonia for 3 hours. The pH was controlled at 7.5 for the first 2.4 hours and at 9.0 for the last 0.6 hours by adjusting the concentration of the alkaline gas ammonia. After that, the carrier DUT1 was obtained by air calcination at 550°C for 3 hours.

[0058] Example 2

[0059] Preparation of hydrocracking catalyst support:

[0060] The preparation method of boron- and silicon-containing pseudoboehmite is the same as that in Example 1, except that 25 L of a mixed solution of borate alkyl alcohol amide ester and trimethylsiloxane is added to a dilute sodium aluminate solution to obtain boron- and silicon-containing pseudoboehmite.

[0061] 73g of boron- and silica-containing pseudoboehmite, 26g of Y-type molecular sieve (same as in Example 1), and 1g of guar gum powder were dry-mixed and rolled in a roller for 20 minutes. Then, 12.8g of dilute nitric acid (4.0g HNO3 / 100cm³) was added. 3 The mixture was kneaded, extruded into strips, and then dried at 120°C in an alkaline atmosphere containing ammonia for 3 hours. The pH was controlled at 7.5 for the first 2.4 hours and at 9.0 for the last 0.6 hours by adjusting the concentration of the alkaline gas ammonia. Finally, it was calcined at 550°C for 3 hours to obtain the carrier DUT2.

[0062] Example 3

[0063] Preparation of hydrocracking catalyst support:

[0064] The preparation method of boron- and silicon-containing pseudoboehmite is the same as in Example 1, except that: 384.6 L of concentrated sodium aluminate solution is added to the gelation reactor and diluted with deionized water to 1000 L to prepare a dilute sodium aluminate solution with a concentration of 135 g / L (calculated as Al2O3). 339.4 L of a mixed solution of borate alkyl alcohol amide ester and trimethylsiloxane silicate is added to the dilute sodium aluminate solution to obtain boron- and silicon-containing pseudoboehmite.

[0065] The prepared boron- and silica-containing pseudoboehmite (68g), Y-type molecular sieve (same as in Example 1) (31g), and guar gum powder (1g) were dry-mixed and rolled in a roller for 20 minutes. Then, 13.75g of dilute nitric acid (4.0g HNO3 / 100cm³) was added. 3 The mixture was kneaded, extruded into strips, and then dried at 120°C in an alkaline atmosphere containing ammonia for 3 hours. The pH was controlled at 7.5 for the first 2.2 hours and at 9.0 for the next 0.8 hours by adjusting the concentration of the alkaline gas ammonia. Finally, the mixture was calcined at 550°C for 3 hours to obtain the carrier DUT3.

[0066] Example 4

[0067] Preparation of hydrocracking catalyst support:

[0068] The preparation method of boron- and silica-containing pseudoboehmite is the same as that in Example 1, except that: a mixed solution of succinimide borate and polyvinyl silicate is added to a dilute sodium aluminate solution to obtain boron- and silica-containing pseudoboehmite.

[0069] The prepared boron- and silica-containing pseudoboehmite (76g), Y-type molecular sieve (same as in Example 1) (23g), and guar gum powder (1g) were dry-mixed and rolled in a roller for 20 minutes. Then, 13.75g of dilute nitric acid (4.0g HNO3 / 100cm³) was added. 3 The mixture was kneaded, extruded into strips, and then dried at 120°C in an alkaline atmosphere containing ammonia for 3 hours. The pH was controlled at 7.5 for the first 2.6 hours and at 9.0 for the last 0.4 hours by adjusting the concentration of the alkaline gas ammonia. Finally, it was calcined at 570°C for 3 hours to obtain the carrier DUT4.

[0070] Example 5

[0071] Preparation of hydrocracking catalyst support:

[0072] Prepare a concentrated sodium aluminate solution with a caustic ratio of 1.35 and a concentration of 320 g / L (calculated as Al2O3) by mixing industrial grade 1 aluminum hydroxide powder and industrial grade 1 sodium hydroxide.

[0073] Take 266L of the solution and add it to the gelation reactor. Dilute it with deionized water to 1000L to prepare a dilute sodium aluminate solution with a concentration of 85g / L (calculated as Al2O3). Add 116.5L of a mixed solution of borate alkyl alcohol amide ester and trimethylsiloxane. The concentration of boron in the mixed solution is 15g / L (calculated as B2O3) and the concentration of silicon is 170g / L (calculated as SiO2).

[0074] Air is introduced from the bottom of the reactor for stirring, and the air flow rate is controlled at 1.3 m / s. 3 After thorough mixing, a mixture of air and CO2 is introduced at a flow rate of 2.2 m³ / h. 3 / h, wherein the volume fraction of CO2 is 43%, when the pH value of the slurry in the reactor drops to 9.8, the mixed gas is turned off and the reaction is stopped. The slurry is filtered to obtain a filter cake, which is washed with deionized water at 65°C until neutral, and dried at 120°C for 3 hours to obtain the boron- and silicon pseudoboehmite of the present invention.

[0075] The prepared boron- and silica-containing pseudoboehmite (69g), Y-type molecular sieve (same as in Example 1) (30g), and guar gum powder (1g) were dry-mixed and compacted in a roller for 20 minutes. Then, 12.8g of dilute nitric acid (4.0g HNO3 / 100cm³) was added. 3 The mixture was kneaded, extruded into strips, and then dried at 120°C in an alkaline atmosphere containing ammonia for 3 hours. The pH was controlled at 8.0 for the first 2.4 hours and at 9.5 for the last 0.6 hours by adjusting the concentration of the alkaline gas ammonia. Finally, the mixture was calcined at 560°C for 3 hours to obtain the carrier DUT5.

[0076] Example 6

[0077] Preparation of hydrocracking catalyst support:

[0078] The preparation method of boron- and silicon pseudoboehmite is the same as that in Example 5, except that the reaction is stopped when the final pH value of gelation is 11.3, and the boron- and silicon pseudoboehmite of the present invention is obtained.

[0079] 73g of boron- and silica-containing pseudoboehmite, 26g of Y-type molecular sieve (same as in Example 1), and 1g of guar gum powder were dry-mixed and rolled in a roller for 20 minutes. Then, 12.8g of dilute nitric acid (4.0g HNO3 / 100cm³) was added. 3 The mixture was kneaded, extruded into strips, and then dried at 120°C in an alkaline atmosphere containing ammonia for 3 hours. The pH was controlled at 8.0 for the first 2.4 hours and at 9.5 for the last 0.6 hours by adjusting the concentration of the alkaline gas ammonia. Finally, it was calcined at 550°C for 3 hours to obtain the carrier DUT6.

[0080] Comparative Example 1

[0081] Preparation of hydrocracking catalyst support:

[0082] Prepare a concentrated sodium aluminate solution with a caustic ratio of 1.15 and a concentration of 351 g / L (calculated as Al2O3) by mixing industrial grade 1 aluminum hydroxide powder and industrial grade 1 sodium hydroxide.

[0083] Take 285L of the solution and add it to the gelation reactor. Dilute it with deionized water to 1000L to prepare a dilute sodium aluminate solution with a concentration of 100g / L (calculated as Al2O3). Add 140L of a mixed solution of boric acid and water glass. The concentration of boron in the mixed solution is 20g / L (calculated as B2O3) and the concentration of silicon is 68g / L (calculated as SiO2).

[0084] Air is introduced from the bottom of the reactor for stirring, and the air flow rate is controlled at 1.8 m / s. 3 After thorough mixing, a mixture of air and CO2 is introduced at a flow rate of 1.85 m³ / h. 3 / h, where the volume fraction of CO2 is 55%, when the pH value of the slurry in the reactor drops to 10.5, the mixed gas is turned off and the reaction is stopped. The slurry is filtered to obtain a filter cake, which is washed with deionized water at 65℃ until neutral to obtain boron- and silicon-containing pseudoboehmite.

[0085] The prepared boron- and silica-containing pseudoboehmite (69g), Y molecular sieve (same as in Example 1) (30g), and guar gum powder (1g) were dry-mixed and rolled in a roller for 20 minutes. Then, 12.8g of dilute nitric acid (4.0g HNO3 / 100cm³) was added. 3 The mixture is kneaded, extruded into strips, dried at 120°C for 3 hours, and calcined at 550°C for 3 hours to obtain carrier DUT7.

[0086] Comparative Example 2

[0087] Preparation of hydrocracking catalyst support:

[0088] According to the current industrial carbonization method for producing silicon-containing pseudoboehmite, industrial grade 1 aluminum hydroxide powder and industrial grade 1 sodium hydroxide are used to prepare a concentrated sodium aluminate solution with a caustic ratio of 1.15 and a concentration of 351 g / L (calculated as Al2O3).

[0089] 285 L of the solution was added to a gelling reactor and diluted with deionized water to 1000 L, preparing a dilute sodium aluminate solution with a concentration of 100 g / L (Al₂O₃). Air was introduced from the bottom of the reactor for stirring, with the air flow rate controlled at 1.8 m / s. 3 After thorough mixing, a mixture of air and CO2 is introduced at a flow rate of 1.85 m³ / h. 3 / h, where the volume fraction of CO2 is 55%, when the pH value of the slurry in the reactor drops to 12.5, 140L of a mixed solution of boric acid and water glass is added, in which the concentration of boron as B2O3 is 20g / L and the concentration of silicon as SiO2 is 68g / L; the mixed gas of air and CO2 continues to be introduced, and when the pH value of the slurry in the reactor drops to 10.5, the mixed gas is turned off and the reaction is stopped. The slurry is filtered to obtain a filter cake, which is washed with deionized water at 65℃ until neutral to obtain boron and silicon pseudoboehmite;

[0090] The prepared boron- and silica-containing pseudoboehmite (69g), Y molecular sieve (same as in Example 1) (30g), and guar gum powder (1g) were dry-mixed and rolled in a roller for 20 minutes. Then, 12.8g of dilute nitric acid (4.0g HNO3 / 100cm³) was added. 3 The mixture was kneaded, extruded into strips, and then dried at 120°C in an alkaline atmosphere containing ammonia for 3 hours. The pH was controlled at 8.0 for the first 2.4 hours and at 9.5 for the last 0.6 hours by adjusting the concentration of the alkaline gas ammonia. Finally, it was calcined at 550°C for 3 hours to obtain the carrier DUT8.

[0091] Examples 7-12

[0092] Preparation of hydrocracking catalysts:

[0093] Based on the weight of the catalyst: 6.2% is nickel oxide and 23% is tungsten oxide, which are used to prepare a tungsten-nickel metal solution. The solutions are impregnated with equal volumes of carriers DUT1 to DUT6, dried at 120°C for 3 hours, and calcined in air at 500°C for 2 hours to obtain hydrocracking catalysts in the order of Cat1 to Cat6.

[0094] All prepared hydrocracking catalysts Cat1–Cat6 were evaluated in a 100 mL small-scale hydrocracking apparatus using vacuum-pressurized wax oil as feedstock. The hydrocracking performance of the catalysts was assessed. The operating conditions for the evaluation experiment were as follows: reaction temperature 375 °C, hydrogen partial pressure 14.5 MPa, and liquid hourly space velocity 1.0 h⁻¹. -1 The hydrogen-to-oil volume ratio was 1200:1. The properties of the feedstock oil used in the activity evaluation experiment are shown in Table 2, and the activity evaluation results are shown in Table 4.

[0095] Comparative Examples 3-4

[0096] Based on the catalyst weight: 6.2% is nickel oxide and 23% is tungsten oxide, a tungsten-nickel metal solution is prepared, and the supports DUT7 and DUT8 are impregnated with equal volumes. After drying at 120℃ for 3 hours and calcining in air atmosphere at 500℃ for 2 hours, the hydrocracking catalysts are Cat7 and Cat8, respectively.

[0097] All prepared hydrocracking catalysts Cat7 and Cat8 were evaluated in a 100 mL small-scale hydrocracking unit using vacuum wax oil as feedstock. The hydrocracking performance of the catalysts was assessed. The operating conditions for the evaluation experiment were as follows: reaction temperature 375 °C, hydrogen partial pressure 14.5 MPa, and liquid hourly space velocity 1.0 h⁻¹. -1 The hydrogen-to-oil volume ratio was 1200:1. The properties of the feedstock oil used in the activity evaluation experiment are shown in Table 2, and the activity evaluation results are shown in Table 4.

[0098] Table 1. Physicochemical properties of the supports prepared in Examples 1-6 and Comparative Examples 1-2

[0099]

[0100]

[0101] Table 2 Properties of Crude Oil

[0102]

[0103] Table 3. Physicochemical properties of the catalysts prepared in Examples 7-12 and Comparative Examples 3-4

[0104]

[0105] Table 4 Catalyst performance of Examples 7-12 and Comparative Examples 3-4

[0106]

[0107]

[0108]

[0109] The hydrocracking catalyst prepared by this invention has the advantages of high strength and high macropore content, making it suitable for the flexible production of high-quality heavy naphtha, jet fuel, diesel, and hydrocracking tail oil. It exhibits excellent activity and selectivity for the target product. Because the hydrocracking catalyst prepared by this invention has an increased macropore ratio, secondary cracking of intermediate products is avoided, resulting in better selectivity for the target product and reduced hydrogen consumption. Furthermore, because the invention better coordinates the dual-functionality of hydrocracking and cracking, the typical properties of the main products are improved compared to the comparative method.

[0110] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the implementation. The scope of protection of the present invention should be determined by the scope defined in the claims. Other variations or modifications can be made based on the above description. Obvious variations or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A method for preparing a hydrocracking catalyst support, characterized in that: The method includes the following steps: (1) Place sodium aluminate solution in a gelling reactor, add boron and silicon precursor mixed solution and mix evenly, introduce air and CO2 mixed gas to control the pH value of slurry, stop introducing mixed gas when the pH value of slurry reaches the endpoint pH value, filter the slurry, wash and dry to obtain boron and silicon pseudoboehmite. (2) Boron- and silicon-containing pseudoboehmite, molecular sieve, and molding aid are mixed, molded, dried in an alkaline gas atmosphere, with the pH controlled at 7-12, and then calcined to obtain a hydrocracking catalyst support. In step (1), the boron- and silicon precursor mixed solution is a mixed solution of boron-based surfactant and silicon surfactant; The boron-based surfactant is one or more of the following: glycerol ester borate surfactants, borate alkyl alcohol amide ester surfactants, and borate amphoteric surfactants. The silicon surfactant is one or more of the following: siloxane surfactant, polysiloxane or carbosilane surfactant and polysilane surfactant; In the boron- and silicon precursor mixed solution, the concentration of boron as B2O3 is 10 g to 40 g / L and the concentration of silicon as SiO2 is 20 to 180 g / L. The sodium aluminate solution has a concentration of 80-150 g / L based on Al2O3 and a caustic ratio of 1.10-1.40; the sodium aluminate solution is prepared using conventional methods. The volume of the boron- and silicon precursor mixed solution is 1 / 10 to 2 / 5 of the volume of the sodium aluminate solution; In step (2), the alkaline gas is one or a combination of ammonia, phosphine, and hydrazine; In step (2), the drying process is as follows: for 80% to 90% of the time before drying, the pH range of the alkaline gas atmosphere is controlled to be 7 to 8 by adjusting the concentration of alkaline gas; for 10% to 20% of the time after drying, the pH range of the alkaline gas atmosphere is controlled to be 9 to 12 by adjusting the concentration of alkaline gas; the drying temperature is 50 to 160°C and the drying time is 1 to 15 hours.

2. The preparation method according to claim 1, characterized in that: In step (1), the mixing process involves introducing air from the bottom of the reactor for stirring, with an air flow rate of 1.0~2.0 m / s. 3 / h; The final pH value of the slurry was 9.5~11.5; The volume fraction of CO2 in the air-CO2 mixture is 30%–60%; the flow rate of the mixed gas introduced per cubic meter of sodium aluminate solution is 1.5–2.5 m³ / s. 3 / h.

3. The preparation method according to claim 1, characterized in that: In step (1), the boron- and silicon precursor mixed solution has a boron concentration of 10-20 g / L (calculated as B2O3) and a silicon concentration of 50-170 g / L (calculated as SiO2).

4. The preparation method according to claim 1, characterized in that: In step (1), the concentration of the sodium aluminate solution, calculated as Al2O3, is 85~140 g / L; the preparation process of the sodium aluminate solution is as follows: aluminum hydroxide and sodium hydroxide are prepared by high-temperature reaction.

5. The preparation method according to claim 1, characterized in that: In step (2), the roasting temperature is 450~650℃ and the roasting time is 1~10h.

6. The preparation method according to claim 1, characterized in that: In step (2), the molding aid is selected from at least one of pectinic acid, extrusion aid, and adhesive; The pectic acid is one or a mixture of citric acid and nitric acid; The adhesive is small-pore alumina; The extrusion aid is one or more of starch, polyvinyl alcohol, polyacrylamide, methylcellulose, and guar gum powder; The molecular sieve is selected from at least one of Y-type molecular sieve, β-type molecular sieve, and ZSM-5 type molecular sieve.

7. The preparation method according to claim 1, characterized in that: In step (2), the drying process is controlled by adjusting the concentration of alkaline gas to maintain the pH range of the alkaline gas atmosphere at 9-10; the drying temperature is 85-120℃.

8. The preparation method according to claim 2, characterized in that: The flow rate of the mixed gas introduced into each cubic meter of sodium aluminate solution is 1.7~2.3 m³. 3 / h.

9. The preparation method according to claim 5, characterized in that: The roasting temperature is 500~580℃.

10. The preparation method according to claim 6, characterized in that: The colloidal acid is a mixture of citric acid and nitric acid.

11. A hydrocracking catalyst support prepared by the method according to any one of claims 1-10, characterized in that: the support comprises a molecular sieve and boron- and silica-containing pseudoboehmite; Based on the weight of the carrier, the carrier contains 40% to 90% boron and 90% siliceous boehmite, and 10% to 60% molecular sieve. The carrier has the following properties: a specific surface area of ​​210~480 m². 2 / g, pore volume is 0.35~0.75ml / g, and pores with a diameter >15nm account for 20%~30% of the total pore volume; Based on the properties of the dry basis, the carrier contains 1.0% to 5.0% boron (B2O3) and 1.0% to 20.0% silicon (SiO2).

12. The hydrocracking catalyst support according to claim 11, characterized in that: Based on the weight of the carrier, the carrier contains 55% to 75% boron and silicoboehmite, and 25% to 45% molecular sieve.

13. A hydrocracking catalyst, characterized in that: The catalyst is prepared by impregnating a hydrocracking catalyst support according to any one of claims 11-12 with a solution containing an active metal, followed by drying and calcination.

14. The hydrocracking catalyst according to claim 13, characterized in that: The active metal is a Group VIII B or Group VIB metal, wherein the Group VIII B metal is one or two of Co and Ni, and the Group VIB metal is one or two of W and Mo. Based on the weight of the catalyst, the content of Group VIII B metals as oxides is 2wt% to 16wt%, the content of Group VIB metals as oxides is 10wt% to 35wt%, and the content of the hydrocracking catalyst support is 50wt% to 80wt%.

15. The hydrocracking catalyst according to claim 14, characterized in that: Based on the weight of the catalyst, the content of Group VIII B metals as oxides is 5wt% to 11wt%, the content of Group VIB metals as oxides is 15wt% to 30wt%, and the content of the hydrocracking catalyst support is 65wt% to 75wt%.

16. The hydrocracking catalyst according to claim 13, characterized in that: The catalyst further includes an auxiliary agent, which is one or more oxides of P, B, Ti, and Zr, and the content of the auxiliary agent, based on the weight of the catalyst, is less than 6% of the weight of the hydrocracking catalyst.

17. The hydrocracking catalyst according to claim 16, characterized in that: The content of the additive, based on the weight of the catalyst, is 0.1% to 5.0% of the weight of the hydrocracking catalyst.

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