A method for preparing a hydrocracking catalyst

Abstract

This invention discloses a hydrocracking catalyst, comprising a support and an active metal, wherein the support comprises SAPO-34 molecular sieve, and the SAPO-34 molecular sieve has a specific surface area of ​​400-550 m². 2 / g, pore volume 0.38-0.45cm³ 3 / g. This invention also discloses its preparation and application. The SAPO-34 molecular sieve contained in this invention has a higher specific surface area and pore volume, making it more suitable for the diffusion and reaction of macromolecules in the hydrocracking of wax oil, and inhibiting carbon deposition.

Description

Technical Field

[0001] This invention relates to a method for preparing a hydrocracking catalyst. Background Technology

[0002] Hydrocracking technology is a crucial technology for producing high-quality, clean petroleum products, boasting unique advantages such as strong feedstock adaptability, flexible processing options, and high product quality. Hydrocracking catalysts used in industrial applications mainly include alumina, molecular sieves, active metals, and silica-alumina oxides. Alumina, molecular sieves, and silica-alumina oxides form the support, whose primary function is to provide suitable acidic sites during the hydrocracking reaction to promote the breaking of chemical bonds in heavy oil molecules, while also providing abundant specific surface area. Active metals primarily provide the hydrogenation function.

[0003] Existing methods for preparing hydrocracking catalysts often rely on Y-type molecular sieves or / and β-type molecular sieves for their acidic components. However, these molecular sieves offer limited means for controlling the yield and quality of the target product. Simply pursuing a high yield of the target product can easily lead to low liquid yield and poor economic efficiency. On the other hand, pursuing a high liquid yield makes it difficult to obtain a considerable economic oil product yield. Furthermore, the pore distribution of a single molecular sieve is uniform, and the acidic properties and environment within the pores are not rich enough, making it difficult for the prepared catalyst to achieve optimal performance. Summary of the Invention

[0004] In order to at least partially overcome the shortcomings of the prior art, the present invention provides a hydrocracking catalyst.

[0005] The hydrocracking catalyst includes SAPO-34 molecular sieve with excellent acidity. Sucrose is dissolved in water to form an aqueous solution. An aluminum source, a silicon source, a phosphorus source, a template agent, and water are added to the aqueous solution obtained in step (1) and mixed evenly. The mixture is stirred to form a mixture. Polyoxyethylene polyoxypropylene octadecyl alcohol ether is added to the mixture, and after rapid mixing, crystallization is carried out to obtain SAPO-34 molecular sieve. The amount of polyoxyethylene polyoxypropylene octadecyl alcohol ether added is 0.1-20 wt% based on 100% of the aluminum source, and the amount of sucrose is 0.1-4.9 wt%.

[0006] This invention discloses a hydrocracking catalyst, which is made by supporting an active metal on a support. The preparation process of the support includes kneading, extruding, drying, and calcining a mixture of SAPO-34 molecular sieve, β molecular sieve, amorphous silica-alumina, Y molecular sieve, and alumina. The active metal includes oxides of W and Ni. The hydrocracking catalyst of this invention can inhibit over-cracking in the hydrocracking reaction of wax oil containing macromolecules, improve the conversion of wax oil macromolecule reactants to target products, increase the production of jet fuel and naphtha during the hydrocracking process of wax oil, and lower the freezing point of jet fuel.

[0007] As one aspect of the present invention, a hydrocracking catalyst is disclosed, comprising a support and an active metal, wherein the support comprises a SAPO-34 molecular sieve, and the SAPO-34 molecular sieve, prior to crystallization, contains polyoxyethylene polyoxypropylene octadecyl alcohol ether and sucrose, and has a specific surface area of ​​300-600 m². 2 / g, pore volume 0.2-0.5cm³ 3 / g, silicon-to-aluminum ratio 0.01-0.5. Based on the weight of aluminum source, add 0.1-20wt% of polyoxyethylene polyoxypropylene octadecyl alcohol ether and 0.1-4.9wt% of sucrose.

[0008] In a specific embodiment, the carrier comprises SAPO-34 molecular sieve, β molecular sieve, amorphous silica-alumina, γ molecular sieve, and alumina, wherein the γ molecular sieve content is 10wt%–55wt%, the SAPO-34 molecular sieve content is 1wt%–20wt%, the β molecular sieve content is 1wt%–20wt%, and the amorphous silica-alumina content is 10wt%–45wt%. The carrier is obtained by first mixing a 2% aqueous solution of methylcellulose with SAPO-34 molecular sieve and β molecular sieve, then mixing with amorphous silica-alumina, γ molecular sieve, and alumina, extruding, and drying.

[0009] In a specific embodiment, the content of the carrier is 63-95 wt%; and the content of the active metal, based on the weight of the oxide, is 5-37 wt%.

[0010] In a specific embodiment, the active metal is W and / or Ni; the active metal, by weight of oxides, has an oxide content of 1-28 wt% for W and an oxide content of 4-9 wt% for Ni.

[0011] In a specific embodiment, the catalyst further includes P, and the oxide content of P is 0.1-3 wt% by weight of oxide.

[0012] In a specific embodiment, the amorphous silica-alumina contains 15-70 wt% silica; the Y molecular sieve has a silica-to-alumina ratio of 7-30 and a cell parameter of 2.43-2.46 nm; the β molecular sieve has a silica-to-alumina ratio of 20-110, a non-framework aluminum content of less than 3%, and a specific surface area of ​​400-600 m². 2 / g.

[0013] As another aspect of the present invention, a method for preparing SAPO-34 molecular sieves is provided, comprising:

[0014] (1) Add aluminum source, silicon source, phosphorus source and template agent to an aqueous solution of sucrose and mix to obtain a mixture;

[0015] (2) Add polyoxyethylene polyoxypropylene octadecyl alcohol ether and crystallize to obtain SAPO-34 molecular sieve.

[0016] In step (1), the molar ratio of silicon source: aluminum source: phosphorus source: template agent is (0.5-2):(2-4):(2.5-4):(1-6), and further, the molar ratio of silicon source: aluminum source: phosphorus source: template agent: water is (0.5-2):(2-4):(2.5-4):(1-6):(90-180).

[0017] In step (2), the amount of polyoxyethylene polyoxypropylene octadecyl alcohol ether added is 0.1 to 20 wt% based on 100% of the weight of the aluminum source.

[0018] In a specific embodiment, the aluminum source is one or more of boehmite, aluminum sulfate, aluminum chloride, and aluminum nitrate, preferably boehmite; the silicon source is one or more of activated silica, silica fume, sodium silicate, tetraethyl orthosilicate, silica sol, water glass, and silica fume, preferably silica sol; the template agent is one or more of diethylamine, triethylamine, morpholine, diisopropylamine, di-n-propylamine, diethanolamine, triethanolamine, tetraethylammonium hydroxide, and N,N-diethylethanol, preferably diethylamine; and the phosphorus source is phosphoric acid or metaphosphoric acid, preferably phosphoric acid.

[0019] As another aspect of the present invention, a method for preparing a carrier is provided, comprising: mixing a 2% aqueous solution of methylcellulose with SAPO-34 molecular sieve and β molecular sieve, then mixing with amorphous silica-alumina, Y molecular sieve and alumina, extruding, and drying to obtain the carrier.

[0020] As another aspect of the present invention, a method for preparing the above-mentioned catalyst is provided, comprising: impregnating a support in an impregnation solution containing an active metal, drying and calcining it to obtain a hydrocracking catalyst.

[0021] The impregnation process involves supersaturating the carrier with a W-Ni complex impregnation solution.

[0022] Furthermore, the W-Ni complex impregnation solution is prepared by mixing and dissolving a soluble active metal salt, phosphoric acid, and a complexing agent in deionized water or ammonia water. The complexing agent is one or more of citric acid, ethanolamine, diethanolamine, triethanolamine, glycine, ethylenediamine, and ethylenediaminetetraacetic acid, preferably citric acid or ethanolamine.

[0023] The hydrocracking catalyst of the present invention can be used for the hydrocracking reaction of straight-run wax oil and / or diesel feedstock, and is particularly suitable for the catalytic hydrocracking reaction of feedstock with a dry point ≤540°C, residual carbon ≤0.5ω%, and nitrogen content ≤1500μg / g.

[0024] This invention's innovative hydrocracking catalyst utilizes a composite molecular sieve rich in Brønsted acid as a support material. This catalyst promotes selective ring-opening in the hydrocracking reaction, inhibits excessive cracking of reactants, reduces catalyst coking rate, increases jet fuel yield, and also produces naphtha. In the hydrocracking of wax oil, it can significantly improve jet fuel yield and lower the freezing point of aviation kerosene. The SAPO-34 molecular sieve contained in this invention has a higher specific surface area and pore volume, making it more suitable for the diffusion and reaction of macromolecules in wax oil hydrocracking, and inhibiting coking. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 The XRD diffraction pattern of the molecular sieve obtained in the example is compared with that of the molecular sieve obtained in the comparative example.

[0027] Figure 2 The NH3-TPD diagrams for Example 1 and Comparative Example 1 show that the SAPO-34 molecular sieve synthesized in this invention uses more Brønsted acid. Detailed Implementation

[0028] The inventors prepared a hydrocracking catalyst support according to CN111318313A. However, because the SAPO-34 molecular sieve was not optimized for acidity, the SAPO-34 molecular sieve had a relatively high carbon deposition rate, which did not meet the requirements for long-term stability of the catalyst in industrial applications.

[0029] The inventors prepared a hydrocracking catalyst according to WO2020119754A1. The synthetic material only uses silane as a regulator, which is costly and not conducive to reducing catalyst cost and popularizing industrialization.

[0030] The hydrocracking catalyst prepared by the inventors with reference to CN105709844A has low selectivity for jet fuel.

[0031] The inventors prepared a hydrocracking catalyst with relatively low oil selectivity, referring to CN104667969B.

[0032] Since none of the above could meet the inventor's expectations, the inventor made this invention after further research and development.

[0033] The following provides a detailed description of the embodiments of the present invention: These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and processes. However, the scope of protection of the present invention is not limited to the following embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions. wt% in the present invention represents a mass percentage.

[0034] Evaluation and analytical methods included BET determination, true boiling point cutoff, and pour point determination. Specific surface area and pore volume of the samples were determined using a Kanta autosorb-analyzer. Jet kerosene yield was determined using an i-Fischer DIST D-2892CC true boiling point distillation apparatus, and pour point data were determined using a BF-15 pour point analyzer from Dalian Northern Analytical Instruments Co., Ltd.

[0035] Example 1

[0036] (1) Preparation of SAPO-34 molecular sieve

[0037] 0.48 g of sucrose was dissolved in 52.31 g of deionized water. 11.32 g of boehmite, 15.65 g of phosphoric acid, and 5.76 g of silica sol were added to the resulting solution and mixed thoroughly for 1 hour. 9.62 g of diethylamine was added to the resulting solution, followed by 65.11 g of deionized water, and the mixture was stirred thoroughly to obtain a homogeneous mixture. 1.93 g of polyoxyethylene polyoxypropylene octadecyl alcohol ether and 7.0 g of deionized water were then thoroughly mixed and added to the homogeneous mixture. The mixture was stirred rapidly and then transferred to a stainless steel autoclave lined with polytetrafluoroethylene. The autoclave was placed in an oven at 185 °C for 4026 min to crystallize, obtaining a crystallization solution. The crystallization solution was separated and dried. The crystals were then placed in a muffle furnace and calcined at 550 °C for 5 hours to obtain SAPO-34 molecular sieve A-1. The physicochemical properties of the molecular sieve are listed in Table 1.

[0038] (2) Preparation of hydrocracking catalyst

[0039] 31.1g of molecular sieve A-1 and 20.0g of β molecular sieve (all β molecular sieves in this invention are prepared according to CN104071801A) were added to a methylcellulose solution and stirred evenly. Then, 60.8g of Y molecular sieve, 72.5g of alumina, and 61.4g of amorphous silica-alumina were mixed together and kneaded in a kneader for 60 minutes. 127.3g of an acidic solution prepared from water, nitric acid, and citric acid was added to the dry powder all at once. The mixture was first kneaded until it could be extruded into a paste, and then extruded three times through a cylindrical perforated plate with a diameter of 2mm. Finally, it was shaped into a cylindrical strip with a diameter of 1.8mm. The resulting wet strip was dried in an oven at 110℃ for 10 hours and then placed in a muffle furnace and calcined at a programmed temperature of 550℃ for 5 hours to obtain the carrier. At room temperature, 2.1 g of citric acid, 19.4 g of nickel nitrate hexahydrate, 5.1 g of phosphoric acid (85 wt%), and 33.1 g of ammonium metatungstate were dissolved sequentially in 30 mL of deionized water. The impregnation solution was brought to a final volume of 66 mL. 100 g of the support prepared in the previous step was placed in the impregnation tank, and the impregnation solution was poured in. After soaking for 2 h, the impregnated support was first cured in an oven at 30 °C for 10 h, then dried in an oven at 120 °C for 11 h, and finally placed in a muffle furnace and calcined at 540 °C for 6 h to obtain catalyst C-1.

[0040] Example 2

[0041] (1) Preparation of SAPO-34 molecular sieve

[0042] 0.11 g of sucrose was dissolved in 51.31 g of deionized water. 11.41 g of boehmite, 14.65 g of phosphoric acid, and 6.76 g of silica sol were added to the resulting solution and mixed thoroughly for 1 hour. 10.62 g of diethylamine was added to the resulting solution, followed by 75.11 g of deionized water, and the mixture was stirred thoroughly to obtain a homogeneous mixture. 0.37 g of polyoxyethylene polyoxypropylene octadecyl alcohol ether and 6.0 g of deionized water were then thoroughly mixed and added to the homogeneous mixture. The mixture was stirred rapidly and then transferred to a stainless steel autoclave lined with polytetrafluoroethylene. The autoclave was placed in an oven at 185°C for 5026 min to crystallize, resulting in a crystallization solution. The crystallization solution was separated and dried. The crystals were then placed in a muffle furnace and calcined at 550°C for 6 hours to obtain SAPO-34 molecular sieve A-2. The physicochemical properties of the molecular sieve are listed in Table 1.

[0043] (2) Preparation of hydrocracking catalyst

[0044] 22.1g of molecular sieve A-2 and 39.0g of β molecular sieve were added to a methylcellulose solution and stirred until homogeneous. Then, 118.8g of Y molecular sieve, 146.5g of alumina, and 120.4g of amorphous silica-alumina were mixed and kneaded in a kneader for 80 minutes. 245.3g of an acidic solution prepared from water, nitric acid, and citric acid was added to the dry powder at once. The mixture was first kneaded until it could be extruded into a paste. Then, it was extruded three times through a cylindrical perforated plate with a diameter of 2mm, and finally shaped into a cylindrical strip with a diameter of 1.8mm. The resulting wet strip was dried in an oven at 110℃ for 9 hours, and finally placed in a muffle furnace and calcined at a programmed temperature of 550℃ for 6 hours to obtain the carrier. At room temperature, 1.2 g of citric acid, 13.5 g of nickel nitrate hexahydrate, 3.35 g of phosphoric acid (85 wt%), and 22.1 g of ammonium metatungstate were dissolved sequentially in 20 mL of deionized water. The impregnation solution was brought to a final volume of 65 mL. 100 g of the support prepared in the previous step was placed in the impregnation tank, and the impregnation solution was poured in. After soaking for 2 h, the impregnated support was first cured in an oven at 30 °C for 8 h, then dried in an oven at 120 °C for 6 h, and finally placed in a muffle furnace and calcined at 550 °C for 6 h to obtain catalyst C-2.

[0045] Example 3

[0046] (1) Preparation of SAPO-34 molecular sieve

[0047] 0.61 g of sucrose was dissolved in 100.51 g of deionized water. 22.81 g of boehmite, 29.52 g of phosphoric acid, and 13.52 g of silica sol were added to the resulting solution and mixed thoroughly for 2 hours. 19.36 g of diethylamine was added to the resulting solution, followed by 150.3 g of deionized water, and the mixture was stirred thoroughly to obtain a homogeneous mixture. 2.32 g of polyoxyethylene polyoxypropylene octadecyl alcohol ether and 12.35 g of deionized water were then thoroughly mixed and added to the homogeneous mixture. The mixture was stirred rapidly and then transferred to a stainless steel autoclave lined with polytetrafluoroethylene. The autoclave was placed in an oven at 185°C for 3926 minutes to crystallize, obtaining a crystallization solution. The crystallization solution was separated and dried. The crystals were then placed in a muffle furnace and calcined at 550°C for 7 hours to obtain SAPO-34 molecular sieve A-3. The physicochemical properties of the molecular sieve are listed in Table 1.

[0048] (2) Preparation of hydrocracking catalyst

[0049] 25.3g of molecular sieve A-3 and 57.0g of β molecular sieve were added to a methylcellulose solution and stirred until homogeneous. Then, 200.3g of Y molecular sieve, 210.3g of alumina, and 200.3g of amorphous silica-alumina were mixed and kneaded in a kneader for 111 minutes. 485.2g of an acidic solution prepared from water, nitric acid, and citric acid was added to the dry powder at once. The mixture was first kneaded until it could be extruded into a paste. Then, it was extruded three times through a cylindrical perforated plate with a diameter of 2mm, and finally shaped into a cylindrical strip with a diameter of 1.8mm. The resulting wet strip was dried in an oven at 110℃ for 10 hours, and finally placed in a muffle furnace and calcined at a programmed temperature of 550℃ for 8 hours to obtain the carrier. At room temperature, 2.8 g of citric acid, 27.5 g of nickel nitrate hexahydrate, 6.65 g of phosphoric acid (85 wt%), and 41.1 g of ammonium metatungstate were dissolved sequentially in 40 mL of deionized water. The impregnation solution was brought to a final volume of 65 mL. 100 g of the support prepared in the previous step was placed in the impregnation tank, and the impregnation solution was poured in. After soaking for 3 h, the impregnated support was first cured in an oven at 30 °C for 6 h, then dried in an oven at 120 °C for 7 h, and finally placed in a muffle furnace and calcined at 550 °C for 7 h to obtain catalyst C-3.

[0050] Example 4

[0051] 0.31 g of sucrose was dissolved in 51.31 g of deionized water. 11.41 g of boehmite, 14.65 g of phosphoric acid, and 2.52 g of silica sol were added to the resulting solution and mixed thoroughly for 1 hour. 10.62 g of diethylamine was added to the resulting solution, followed by 75.11 g of deionized water, and the mixture was stirred thoroughly to obtain a homogeneous mixture. 1.35 g of polyoxyethylene polyoxypropylene octadecyl alcohol ether and 6.0 g of deionized water were then thoroughly mixed and added to the homogeneous mixture. The mixture was stirred rapidly and then transferred to a stainless steel autoclave lined with polytetrafluoroethylene. The autoclave was placed in an oven at 185°C for 5026 min to crystallize, resulting in a crystallization solution. The crystallization solution was separated and dried. The crystals were then placed in a muffle furnace and calcined at 550°C for 6 hours to obtain SAPO-34 molecular sieve A-6. The physicochemical properties of the molecular sieve are listed in Table 1.

[0052] Example 5

[0053] 25.3g of molecular sieve A-1 and 57.0g of β molecular sieve were added to a methylcellulose solution and stirred until homogeneous. Then, 200.3g of Y molecular sieve, 210.3g of alumina, and 200.3g of amorphous silica-alumina were mixed and kneaded in a kneader for 111 minutes. 485.2g of an acidic solution prepared from water, nitric acid, and citric acid was added to the dry powder at once. The mixture was first kneaded until it could be extruded into a paste. Then, it was extruded three times through a cylindrical perforated plate with a diameter of 2mm, and finally shaped into a cylindrical strip with a diameter of 1.8mm. The resulting wet strip was dried in an oven at 110℃ for 10 hours, and finally placed in a muffle furnace and calcined at a programmed temperature of 550℃ for 8 hours to obtain the carrier. At room temperature, 2.8 g of citric acid, 27.5 g of nickel nitrate hexahydrate, 6.65 g of phosphoric acid (85 wt%), and 41.1 g of ammonium metatungstate were dissolved sequentially in 40 mL of deionized water. The impregnation solution was brought to a final volume of 65 mL. 100 g of the support prepared in the previous step was placed in the impregnation tank, and the impregnation solution was poured in. After soaking for 3 h, the impregnated support was first cured in an oven at 30 °C for 6 h, then dried in an oven at 120 °C for 7 h, and finally placed in a muffle furnace and calcined at 550 °C for 7 h to obtain catalyst C-4.

[0054] Example 6

[0055] 25.3g of molecular sieve A-2 and 57.0g of β molecular sieve were added to a methylcellulose solution and stirred until homogeneous. Then, 200.3g of Y molecular sieve, 210.3g of alumina, and 200.3g of amorphous silica-alumina were mixed and kneaded in a kneader for 111 minutes. 485.2g of an acidic solution prepared from water, nitric acid, and citric acid was added to the dry powder at once. The mixture was first kneaded until it could be extruded into a paste. Then, it was extruded three times through a cylindrical perforated plate with a diameter of 2mm, and finally shaped into a cylindrical strip with a diameter of 1.8mm. The resulting wet strip was dried in an oven at 110℃ for 10 hours, and finally placed in a muffle furnace and calcined at a programmed temperature of 550℃ for 8 hours to obtain the carrier. At room temperature, 2.8 g of citric acid, 27.5 g of nickel nitrate hexahydrate, 6.65 g of phosphoric acid (85 wt%), and 41.1 g of ammonium metatungstate were dissolved sequentially in 40 mL of deionized water. The impregnation solution was brought to a final volume of 65 mL. 100 g of the support prepared in the previous step was placed in the impregnation tank, and the impregnation solution was poured in. After soaking for 3 h, the impregnated support was first cured in an oven at 30 °C for 6 h, then dried in an oven at 120 °C for 7 h, and finally placed in a muffle furnace and calcined at 550 °C for 7 h to obtain catalyst C-5.

[0056] Comparative Example 1

[0057] (1) Preparation of SAPO-34 molecular sieve

[0058] 0.00 g of sucrose was dissolved in 52.31 g of deionized water. 11.32 g of boehmite, 15.65 g of phosphoric acid, and 5.76 g of silica sol were added to the resulting solution and mixed thoroughly for 1 hour. 9.62 g of diethylamine was added to the resulting solution, followed by 65.11 g of deionized water, and the mixture was stirred thoroughly to obtain a homogeneous mixture. 0.00 g of polyoxyethylene polyoxypropylene octadecyl alcohol ether and 7.0 g of deionized water were then thoroughly mixed and added to the homogeneous mixture. The mixture was stirred rapidly and then transferred to a stainless steel autoclave lined with polytetrafluoroethylene. The autoclave was placed in an oven at 185 °C for 4026 min to crystallize, resulting in a crystallization solution. The crystallization solution was separated and dried. The crystals were then placed in a muffle furnace and calcined at 550 °C for 5 hours to obtain SAPO-34 molecular sieve A-4. The physicochemical properties of the molecular sieve are listed in Table 1.

[0059] (2) Preparation of hydrocracking catalyst

[0060] 31.1g of molecular sieve A-4 and 20.0g of β molecular sieve were added to a methylcellulose solution and stirred until homogeneous. Then, 60.8g of Y molecular sieve, 72.5g of alumina, and 61.4g of amorphous silica-alumina were mixed together and kneaded in a kneader for 60 minutes. 127.3g of an acidic solution prepared from water, nitric acid, and citric acid was added to the dry powder at once. The mixture was first kneaded until it could be extruded into a paste. Then, it was extruded three times through a cylindrical perforated plate with a diameter of 2mm, and finally shaped into a cylindrical strip with a diameter of 1.8mm. The resulting wet strip was dried in an oven at 110℃ for 10 hours and then placed in a muffle furnace and calcined at a programmed temperature of 550℃ for 5 hours to obtain the carrier. At room temperature, 2.1 g of citric acid, 19.4 g of nickel nitrate hexahydrate, 5.1 g of phosphoric acid (85 wt%), and 33.1 g of ammonium metatungstate were dissolved sequentially in 30 mL of deionized water. The impregnation solution was brought to a final volume of 66 mL. 100 g of the support prepared in the previous step was placed in the impregnation tank, and the impregnation solution was poured in. After soaking for 2 h, the impregnated support was first cured in an oven at 30 °C for 10 h, then dried in an oven at 120 °C for 11 h, and finally placed in a muffle furnace and calcined at 540 °C for 6 h to obtain catalyst C-6.

[0061] Comparative Example 2

[0062] 2.2 g of sucrose was dissolved in 52.31 g of deionized water. 11.32 g of boehmite, 15.65 g of phosphoric acid, and 5.76 g of silica sol were added to the resulting solution and mixed thoroughly for 1 hour. 9.62 g of diethylamine was added to the resulting solution, followed by 65.11 g of deionized water, and the mixture was stirred thoroughly to obtain a homogeneous mixture. 4.01 g of polyoxyethylene polyoxypropylene octadecyl alcohol ether and 7.0 g of deionized water were then thoroughly mixed and added to the homogeneous mixture. The mixture was stirred rapidly and then transferred to a stainless steel autoclave lined with polytetrafluoroethylene. The autoclave was placed in an oven at 185 °C for 4026 min to crystallize, yielding a crystallization solution. The crystallization solution was separated and dried. The crystals were then placed in a muffle furnace and calcined at 550 °C for 5 hours to obtain SAPO-34 molecular sieve A-5. The physicochemical properties of the molecular sieve are listed in Table 1.

[0063] Preparation of hydrocracking catalysts

[0064] 22.1g of molecular sieve A-5 and 39.0g of β molecular sieve were added to a methylcellulose solution and stirred until homogeneous. Then, 118.8g of Y molecular sieve, 146.5g of alumina, and 120.4g of amorphous silica-alumina were mixed and kneaded in a kneader for 80 minutes. 245.3g of an acidic solution prepared from water, nitric acid, and citric acid was added to the dry powder at once. The mixture was first kneaded until it could be extruded into a paste. Then, it was extruded three times through a cylindrical perforated plate with a diameter of 2mm, and finally shaped into a cylindrical strip with a diameter of 1.8mm. The resulting wet strip was dried in an oven at 110℃ for 9 hours, and finally placed in a muffle furnace and calcined at a programmed temperature of 550℃ for 6 hours to obtain the carrier. At room temperature, 1.2 g of citric acid, 13.5 g of nickel nitrate hexahydrate, 3.35 g of phosphoric acid (85 wt%), and 22.1 g of ammonium metatungstate were dissolved sequentially in 20 mL of deionized water. The impregnation solution was brought to a final volume of 65 mL. 100 g of the support prepared in the previous step was placed in the impregnation tank, and the impregnation solution was poured in. After soaking for 2 h, the impregnated support was first cured in an oven at 30 °C for 8 h, then dried in an oven at 120 °C for 6 h, and finally placed in a muffle furnace and calcined at 550 °C for 6 h to obtain catalyst C-7.

[0065] Comparative Example 3

[0066] 22.1g of molecular sieve A-4 and 39.0g of β molecular sieve were added to a methylcellulose solution and stirred until homogeneous. Then, 118.8g of Y molecular sieve, 146.5g of alumina, and 120.4g of amorphous silica-alumina were mixed and kneaded in a kneader for 80 minutes. 245.3g of an acidic solution prepared from water, nitric acid, and citric acid was added to the dry powder at once. The mixture was first kneaded until it could be extruded into a paste. Then, it was extruded three times through a cylindrical perforated plate with a diameter of 2mm, and finally shaped into a cylindrical strip with a diameter of 1.8mm. The resulting wet strip was dried in an oven at 110℃ for 9 hours, and finally placed in a muffle furnace and calcined at a programmed temperature of 550℃ for 6 hours to obtain the carrier. At room temperature, 1.2 g of citric acid, 13.5 g of nickel nitrate hexahydrate, 3.35 g of phosphoric acid (85 wt%), and 22.1 g of ammonium metatungstate were dissolved sequentially in 20 mL of deionized water. The impregnation solution was brought to a final volume of 65 mL. 100 g of the support prepared in the previous step was placed in the impregnation tank, and the impregnation solution was poured in. After soaking for 2 h, the impregnated support was first cured in an oven at 30 °C for 8 h, then dried in an oven at 120 °C for 6 h, and finally placed in a muffle furnace and calcined at 550 °C for 6 h to obtain catalyst C-8.

[0067] Table 1 Comparison of pore structure parameters of molecular sieve samples from the examples and comparative examples.

[0068] project A-1 A-2 A-3 A-4 A-5 A-6 <![CDATA[Specific surface area m 2 / g]]> 449.3 407.2 423.1 268.3 328.2 456.3 <![CDATA[Pore volume cm 3 / g]]> 0.423 0.372 0.405 0.226 0.263 0.389

[0069] As shown in Table 1, the SAPO-34 molecular sieve synthesized using this invention has a higher specific surface area and a larger pore volume compared to A-4 and A-5 in the comparative examples, which is beneficial for mass and heat transfer of reactants.

[0070] The hydrocracking catalysts prepared in the examples and comparative examples were subjected to activity evaluation tests. These tests were conducted on a 200 mL pilot-scale apparatus using a single-stage series process. The operating conditions were as follows: hydrogen partial pressure 15.0 MPa, hydrogen-to-oil volume ratio 1100:1, liquid hourly space velocity 1.6 h⁻¹, and nitrogen content in the cracking section controlled to be no more than 10 ppm. The product properties are shown in Table 3.

[0071] Table 2 Product Yield

[0072]

[0073] As shown in Table 2, the catalyst of the present invention has excellent hydrocracking activity and is characterized by increasing the production of jet fuel and also producing naphtha.

[0074] As shown in Table 3, the products obtained by the catalyst of the present invention have a lower freezing point for aviation kerosene, and their properties are all higher than those of the comparative catalyst.

[0075] Table 3 Product Properties

[0076] catalyst C-1 C-2 C-3 C-6 C-7 C-8 Aviation kerosene freezing point -60.3 -54.5 -59.3 -51.3 -49.3 -49.1

[0077] The above embodiments are typical examples listed to illustrate the technical solution of the present invention in detail. The present invention shall be subject to the protection scope of the claims and the invention content, and shall not be limited by the described embodiments. Simple substitutions or modifications to the present invention shall still be within the protection scope of the present invention.

Claims

1. A method for preparing SAPO-34 molecular sieves, characterized in that, include: (1) Add aluminum source, silicon source, phosphorus source and template agent to an aqueous solution of sucrose and mix to obtain a mixture; (2) Add polyoxyethylene polyoxypropylene octadecyl alcohol ether and crystallize to obtain SAPO-34 molecular sieve; The amount of polyoxyethylene polyoxypropylene octadecyl alcohol ether added is 0.1~20wt% based on 100% of the aluminum source weight, and the amount of sucrose is 0.1~4.9wt%.

2. The method according to claim 1, characterized in that, In step (1), the molar ratio of silicon source: aluminum source: phosphorus source: template agent is (0.5-2):(2-4):(2.5-4):(1-6).

3. The method according to claim 2, characterized in that, In step (1), the molar ratio of silicon source: aluminum source: phosphorus source: template agent: water is (0.5-2):(2-4):(2.5-4):(1-6):(90-180).

4. The method according to claim 1, characterized in that, In step (1), the aluminum source is one or more of boehmite, aluminum sulfate, aluminum chloride, and aluminum nitrate; the silicon source is one or more of activated silica, silica fume, sodium silicate, tetraethyl orthosilicate, silica sol, and water glass; the template agent is one or more of diethylamine, triethylamine, morpholine, diisopropylamine, di-n-propylamine, diethanolamine, triethanolamine, tetraethylammonium hydroxide, and N,N-diethylethanolamine; and the phosphorus source is phosphoric acid or metaphosphoric acid.

5. The method according to claim 4, characterized in that, In step (1), the aluminum source is boehmite, the silicon source is silica sol, the template agent is diethylamine, and the phosphorus source is phosphoric acid.

6. The SAPO-34 molecular sieve prepared by any one of the methods described in claims 1-5.

7. A hydrocracking catalyst, characterized in that, The hydrocracking catalyst includes a support and an active metal, the support including a SAPO-34 molecular sieve, the SAPO-34 molecular sieve being the SAPO-34 molecular sieve of claim 6; the SAPO-34 molecular sieve having a surface area of 400-550 m 2 / g, a pore volume of 0.38-0.45 cm 3 / g.

8. The catalyst according to claim 7, characterized in that, The carrier comprises SAPO-34 molecular sieve, β molecular sieve, amorphous silica-alumina, Y molecular sieve and alumina, wherein the content of Y molecular sieve is 10 wt% to 55 wt%, the content of SAPO-34 molecular sieve is 1 wt% to 20 wt%, the content of β molecular sieve is 1 wt% to 20 wt%, and the content of amorphous silica-alumina is 10 wt% to 45 wt%.

9. The catalyst according to claim 7, characterized in that, In the catalyst, the content of the support is 63-95 wt%; and the content of the active metal, based on the weight of the oxide, is 5-37 wt%.

10. The catalyst of claim 9, characterized in that, The active metal is W and / or Ni; the active metal, by weight of oxides, has an oxide content of 1-28 wt% for W and an oxide content of 4-9 wt% for Ni.

11. The catalyst of claim 7, characterized in that, The catalyst also includes P, with the oxide content of P being 0.1-3 wt% by weight of oxides.

12. The catalyst of claim 8, characterized in that, The amorphous silicon aluminum has a silicon oxide content of 15-70 wt%; the Y molecular sieve has a silicon aluminum ratio of 7-30 and a unit cell parameter of 2.43-2.46 nm; and the beta molecular sieve has a silicon aluminum ratio of 20-110, a non-framework aluminum content of less than 3%, and a specific surface area of 400-600 m 2 / g.

13. A method for preparing a catalyst support, characterized in that, include: A 2% aqueous solution of methylcellulose is first mixed with SAPO-34 molecular sieve and β molecular sieve, and then mixed with amorphous silica-alumina, γ molecular sieve and alumina, extruded and dried to obtain the carrier; wherein the SAPO-34 molecular sieve is the SAPO-34 molecular sieve as described in claim 6.

14. A method for preparing the catalyst according to any one of claims 7-12, characterized in that, include: The support is impregnated in an impregnation solution containing an active metal, dried, and calcined to obtain a hydrocracking catalyst. The support includes SAPO-34 molecular sieve, which has a specific surface area of ​​300-600 m². 2 / g, pore volume 0.2-0.5cm³ 3 / g, silicon-aluminum ratio 0.01-0.

5.

15. The method of claim 14, characterized in that, The active metal impregnation solution is a W-Ni complex impregnation solution.

16. The method of claim 15, characterized in that, The W-Ni complex impregnation solution is prepared by mixing and dissolving a soluble active metal salt, phosphoric acid, and a complexing agent in deionized water or ammonia water. The complexing agent is one or more of citric acid, ethanolamine, diethanolamine, triethanolamine, aminoacetic acid, ethylenediamine, and ethylenediaminetetraacetic acid.

17. The method of claim 16, characterized in that, The complexing agent is citric acid and / or ethanolamine.

18. The use of any of the hydrocracking catalysts described in claims 7-12 in the hydrocracking reaction of straight-run wax oil and / or diesel feedstock.

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