A nickel-based molecular sieve hydrocracking and isomerization catalyst, its preparation method and application

Abstract

The application provides a nickel-based molecular sieve hydrocracking and isomerization catalyst and a preparation method and application thereof, and relates to the technical field of biofuel production and molecular sieve catalyst preparation. The nickel-based molecular sieve hydrocracking and isomerization catalyst comprises 30-80% of MCM-22 molecular sieve, 15-45% of nickel metal element and gamma-Al2O3. The nickel-based molecular sieve catalyst has good isomerization and cracking performance and high stability.

Description

Technical Field

[0001] This invention relates to the field of biofuel production and molecular sieve catalyst preparation technology, specifically to a nickel-based molecular sieve hydrocracking and isomerization catalyst, its preparation method, and its application. Background Technology

[0002] Biofuels refer to fuel ethanol, biodiesel, and aviation biofuels produced from biological resources. They can replace gasoline and diesel fuel derived from petroleum and represent an important direction for the development and utilization of renewable energy. Compared with traditional fuels such as diesel or gasoline, they produce fewer harmful carbon emissions and are more environmentally friendly and energy-efficient. In recent years, some researchers at home and abroad have proposed biodiesel synthesis technology routes based on catalytic hydrogenation processes, forming hydrocarbon-based biodiesel preparation technologies.

[0003] Hydrocarbon-based biodiesel is mainly C 15 ~C 18 n-Alkanes. Due to their poor cold flow properties, n-alkanes require isomerization-depressant processes to improve the cold flow properties of the product. Typically, in the presence of an isomerization catalyst, long-chain alkanes undergo simultaneous isomerization and cracking reactions. Excessive cracking will reduce the yield of the product fuel oil; insufficient isomerization will fail to meet the cold flow requirements of biofuels. Therefore, to obtain as many valuable biofuel products as possible (biojet fuel and low-pour-point biodiesel), the hydroisomerization process of bio-based long-chain alkanes needs to be strictly controlled, and the selectivity of isomerization and cracking is closely related to the performance of the catalyst. Since the acidic sites on the catalyst surface can simultaneously catalyze the isomerization and cracking reactions of alkanes, appropriate acid strength and quantity are key to balancing the isomerization and cracking reactions.

[0004] Existing technologies for isomerization and cracking catalysts include: Patent CN200910188170.6 discloses a hydrodewaxing catalyst, its preparation method, and its application. This catalyst uses a molecular sieve support modified with metal additives and silicone oil. By sequentially depositing additives and silicone oil, the acidity and pore shape of the inner and outer surfaces of the molecular sieve support are adjusted, thereby improving the isomerization rate of the feedstock. However, it has the following shortcomings: 1) The catalyst preparation process is complex, including multiple impregnation and high-temperature calcination processes, resulting in a long preparation cycle; 2) Due to the addition of additives and silicone oil, the active metal loading is relatively low (1%–15%), leading to low reactivity.

[0005] Patent CN201810935163.7 discloses a hydrocracking catalyst, its preparation method, and its application. The catalyst is prepared by impregnation and contains different types of phosphorus-containing molecular sieves and non-precious metal components. It exhibits excellent cracking performance in the hydrocracking reaction of Saudi vacuum residue. However, this catalyst cannot achieve co-production of biojet fuel and low-pour-point biodiesel and is not suitable for C2044.15 ~C 18 Isomerization of bio-based long-chain alkanes. However, this catalyst requires sulfidation during use, making it unsuitable for processing near-sulfur-free bio-based feedstocks.

[0006] Patent CN201610412721.2 discloses an isomerization dewaxing method for producing bio-jet fuel and a catalyst used in the method. The catalyst is one or more mesoporous molecular sieves selected from ZSM-22, ZSM-23, ZSM-12, and SAPO-11 with silicon surface modification. The active metal component is selected from noble metals Pt and / or Pd with a content of 0.1wt% to 5wt%.

[0007] A paper (Toward the production of renewablediesel over robust Ninanoclusters highly dispersed on a two-dimensional zeolite, NPG AsiaMaterials, 2023, 15, 24) discloses a method for producing biodiesel. The Ni-supported ITQ-2 molecular sieve used is prepared via organic ligand chelation impregnation and grinding. This catalyst requires first preparing MCM-22, then swelling it to obtain ITQ-2, followed by organic ligand chelation, impregnation, and grinding to finally obtain the Ni / ITQ-2 catalyst. The catalyst preparation process is complex and cumbersome, and the catalyst's stability needs improvement.

[0008] CN202011264516.9 discloses a method for preparing a hydroisomerization catalyst support. This method involves first mechanically mixing molecular sieves, amorphous inorganic porous materials, and binder powder in a container to obtain a mixed powder. Then, an additive is mixed with deionized water and added dropwise to the mixed powder. The mixture is then kneaded, homogenized, dried, and calcined to obtain a catalyst support precursor. The raw material molecular sieve is then acid-treated or alkali-treated to obtain a turbid liquid containing molecular sieve fragment structural units, which is then impregnated onto the catalyst support precursor. CN202011257233.1 discloses a method for preparing a hydroisomerization catalyst and its support. This catalyst support is prepared by mixing a modified molecular sieve (including MCM-22) containing a ten-membered ring structure with a metal and / or acid impregnation method, followed by drying and calcination, and then further modifying the resulting amorphous inorganic porous material with metal and / or acid. The preparation processes of the above two catalysts are complex and cumbersome, and it is not described whether isomerization and cracking can be simultaneously achieved.

[0009] Similarly, patent CN202010497292.X discloses a hydroisomerization catalyst, its preparation method, and its application. This catalyst uses ZSM-48 molecular sieve with a hollow spherical structure as a support, and the active metal component is selected from at least one of Group VIII noble metals, prepared by impregnation. Patents US11603501B2 and US20240034945A1 disclose catalyst preparation methods and their application in the production of bio-jet fuel. The catalysts used in these patents cannot simultaneously achieve isomerization and cracking, and all use noble metals as the active component. Although noble metals exhibit high activity at low temperatures, the catalysts are expensive and sensitive to impurities, making them highly susceptible to poisoning.

[0010] Patent CN202111280384.3 discloses a method for hydrodewaxing diesel fuel. The hydrodewaxing catalyst used is a non-precious metal catalyst supported on ZSM-5 molecular sieve treated with steam and other catalysts supported on molecular sieve supports, and is used in a staged loading manner. The invention shows that the preparation process of ZSM-5 molecular sieve support is complicated, energy-intensive, and easily generates acidic and alkaline waste liquids.

[0011] As those skilled in the art will know, petrochemical diesel and biodiesel differ significantly in composition. Petrochemical diesel contains a certain amount of cycloalkanes and aromatics, with a wide carbon number distribution; while biodiesel is almost entirely composed of n-chain alkanes, with carbon numbers concentrated between 15 and 18. Furthermore, existing petrochemical diesel aftertreatment catalysts have relatively singular functions. To ensure higher diesel yields, these catalysts tend to favor isomerization performance, making it difficult to achieve both isomerization and cracking simultaneously. The most common method is to use two reactors, one loaded with cracking catalyst and the other with isomerization catalyst, but this increases equipment investment. Therefore, conventional diesel isomerization depressant catalysts are not suitable for processing biodiesel, especially in processes aimed at producing biojet fuel and simultaneously low-pour-point biodiesel. In view of this, it is necessary to develop a nickel-based molecular sieve hydrocracking and isomerization catalyst for the simultaneous production of biojet fuel and low-pour-point biodiesel. Summary of the Invention

[0012] To address the aforementioned issues, this application provides a nickel-based molecular sieve hydrocracking and isomerization catalyst, its preparation method, and its applications. The method involves embedding nickel metal nanoparticles in situ into an MCM-22 molecular sieve precursor through a eutectic process. Nickel metal atoms are used to modify the surface of the molecular sieve particles, eliminating some acidic centers and forming a metal-MCM-22 molecular sieve catalyst with excellent cracking and isomerization properties. This metal-MCM-22 molecular sieve catalyst is then mixed and shaped to prepare a hydrocracking and isomerization catalyst, which is used in the production of oil-based biojet fuel and low-pour-point biodiesel.

[0013] The present invention provides a nickel-based molecular sieve hydrocracking and isomerization catalyst, wherein the nickel-based molecular sieve hydrocracking and isomerization catalyst comprises 30-80% MCM-22 molecular sieve, 15-45% nickel metal, and γ-Al2O3 by mass fraction, and the total mass fraction of the raw materials MCM-22 molecular sieve, nickel metal, and γ-Al2O3 is 100%.

[0014] The preparation method of the nickel-based molecular sieve hydrocracking and isomerization catalyst includes the following steps:

[0015] S1: Prepare the MCM-22 molecular sieve precursor and adjust the pH to 9-13;

[0016] S2: Nickel metal nanoparticles are embedded in situ into the MCM-22 molecular sieve precursor obtained in step S1, and the pH is adjusted to 8-12 to obtain a metal-MCM-22 molecular sieve complex.

[0017] S3: The metal-MCM-22 molecular sieve composite prepared in step S2 is treated with acid solution and / or alkaline solution, and then filtered, washed with water, dried and calcined in sequence to obtain the metal-MCM-22 molecular sieve catalyst.

[0018] S4: Add aluminum hydroxide dry adhesive powder, dilute nitric acid solution and guar gum powder to the metal-MCM-22 molecular sieve catalyst obtained in step S3, then mix, shape, dry, calcine and reduce to obtain nickel-based molecular sieve hydrocracking and isomerization catalyst; the metal loading is 6-42 wt%.

[0019] Optionally, the preparation method of the MCM-22 molecular sieve precursor in step S1 includes the following steps:

[0020] A viscous liquid was obtained by dissolving a silicon source, an aluminum source, sodium hydroxide, and a template agent in deionized water. The liquid was then hydrothermally treated at 30–80 °C to obtain the MCM-22 molecular sieve precursor.

[0021] The chemical composition of the viscous liquid, calculated by the mass of oxides, is SiO2:Al2O3:Na2O:template:H2O = (20-80):(0.5-2):(10-50):(5-30):(1000-5000). Preferably, the chemical composition of the viscous liquid is SiO2:Al2O3:Na2O:template:H2O = (20-70):(0.5-1.5):(10-40):(5-20):(1000-4000).

[0022] Furthermore, in step S1, a precursor of MCM-22 molecular sieve with a specific structure is obtained, which promotes the formation of the subsequent MCM-22 molecular sieve structure and lays the foundation for the subsequent intercalation of active metals.

[0023] Optionally, the preparation method of the metal-MCM-22 molecular sieve complex in step S2 includes the following steps:

[0024] Nickel salt was added to the MCM-22 molecular sieve precursor, and a crystallization reaction was carried out at 120-180℃ for 3-9 days. After filtration, washing and drying, a metal-MCM-22 molecular sieve composite with nickel metal nanoparticles embedded was obtained.

[0025] The chemical composition of the feed, calculated by the mass of the oxides, is SiO2:Al2O3:NiO:Na2O:template:H2O = (20-80):(0.5-2):(5-35):(10-50):(5-30):(1000-5000). Preferably, the chemical composition of the feed, calculated by the mass of the oxides, is SiO2:Al2O3:NiO:Na2O:template:H2O = (30-80):(1-2):(10-35):(20-50):(10-30):(2000-5000).

[0026] Furthermore, in step S2, nickel metal nanoparticles are in situ embedded in the molecular sieve through a co-hydrothermal process of nickel salt and MCM-22 molecular sieve precursor. On the one hand, the particle size of the molecular sieve is controlled, and on the other hand, the surface of the molecular sieve particles is modified to appropriately reduce the number and intensity of acid centers, thereby obtaining a molecular sieve material with moderate cracking performance.

[0027] Optionally, nickel salts include one or more of nitrates, nitrites, sulfates, chlorides, basic carbonates, and acetates.

[0028] Optionally, the template agent is hexamethyleneimine.

[0029] Optionally, the preparation method of the metal-MCM-22 molecular sieve catalyst in step S3 includes the following steps:

[0030] The metal-MCM-22 molecular sieve composite was treated with an acid solution at a temperature of 40–60 °C. The treated material was then filtered, washed with water, dried, and calcined at 450–600 °C to obtain the metal-MCM-22 molecular sieve catalyst.

[0031] The metal-MCM-22 molecular sieve composite was treated with an alkaline solution at a temperature of 50–80 °C. The treated material was then filtered, washed with water, dried, and calcined at 450–600 °C to obtain the metal-MCM-22 molecular sieve catalyst.

[0032] Furthermore, the preparation method of the metal-MCM-22 molecular sieve catalyst in step S3 may include the following steps: first, the metal-MCM-22 molecular sieve composite is treated with an acid solution at a temperature of 40-70°C, and then the treated material is sequentially filtered, washed with water, and dried; then, the metal-MCM-22 molecular sieve composite is treated with an alkaline solution at a temperature of 50-80°C, and then the treated material is sequentially filtered, washed with water, dried, and calcined at 450-600°C to obtain the metal-MCM-22 molecular sieve catalyst;

[0033] Alternatively, the metal-MCM-22 molecular sieve composite can be treated first with an inorganic alkaline solution at a temperature of 50–80°C, and then the treated material can be filtered, washed with water, and dried sequentially. Then, the metal-MCM-22 molecular sieve composite can be treated with an acid solution at a temperature of 40–70°C, and then the treated material can be filtered, washed with water, dried, and calcined at 450–600°C sequentially to obtain the metal-MCM-22 molecular sieve catalyst.

[0034] Furthermore, in step S3, removing the template agent through high-temperature treatment can improve the thermal and chemical stability of the molecular sieve.

[0035] Optionally, in step S4, the mass ratio of the metal-MCM-22 molecular sieve catalyst, aluminum hydroxide dry adhesive powder, dilute nitric acid solution, and guar gum powder is (30-70):(2-4):(2-4):(10-30). Preferably, in step S4, the mass ratio of the metal-MCM-22 molecular sieve catalyst, aluminum hydroxide dry adhesive powder, dilute nitric acid solution, and guar gum powder is (30-50):(2-4):(2-4):(10-20).

[0036] Optionally, the properties of the metal-MCM-22 molecular sieve catalyst are as follows: BET specific surface area of ​​200–500 m². 2 The total pore volume is 0.30–0.90 cm³. 3 / g, SiO2:Al2O3 molar ratio = 15~80.

[0037] Optionally, the acid solution includes one or more of hydrochloric acid, phosphoric acid, nitric acid, acetic acid, tartaric acid, and citric acid; the concentration of the acid solution is 0.1 to 0.5 mol / L; preferably, the acid solution is a mixed acid solution of hydrochloric acid and phosphoric acid, with a mass ratio of hydrochloric acid to phosphoric acid of 1:1.

[0038] Optionally, the alkaline solution includes one or more of sodium hydroxide, potassium hydroxide, and ammonia water; the concentration of the alkaline solution is 0.1 to 0.5 mol / L; preferably, the alkaline solution is a mixed alkaline solution of sodium hydroxide and ammonia water, with a mass ratio of sodium hydroxide to ammonia water of 1:1.

[0039] Optionally, the silicon source may include one or two of silica sol, silica, sodium silicate, and kaolin.

[0040] Optionally, the aluminum source may include one or two of aluminum sulfate, aluminum nitrate, aluminum chloride, and sodium aluminate.

[0041] Another aspect of this invention provides the application of a nickel-based molecular sieve hydrocracking and isomerization catalyst in the hydroisomerization / cracking reaction of bio-based long-chain alkanes, wherein the bio-based long-chain alkanes are derived from the hydrodeoxygenation process of bio-oils and have a C60-400 ppm composition. 15 ~C 18 A mixture of straight-chain alkanes with a sulfur content of <3 ppmw.

[0042] Furthermore, regarding C 15 ~C 18 For n-alkane-based biodiesel, existing catalysts have relatively simple structures and uneven acid strength and quantity distribution, resulting in an inability to simultaneously achieve isomerization and cracking performance during hydroisomerization or cracking. This application utilizes nickel metal atoms to induce the growth of MCM-22 molecular sieve precursors and modifies the surface of the molecular sieve particles to eliminate some acidic centers, forming a metal-MCM-22 molecular sieve catalyst with excellent cracking and isomerization performance. Application in C 15 ~C 18 For n-alkane-based biodiesel, under mild conditions (e.g., 260°C), the cracking rate is not less than 43%, and the isomerization rate is not less than 42%, simultaneously achieving good isomerization and cracking performance. Preferably, when the reaction is carried out at elevated temperatures (e.g., 300°C), the cracking rate is not less than 61%, and the isomerization rate is not less than 52%.

[0043] Optionally, the hydrocracking and isomerization reaction conditions are: reaction temperature 200–300℃, reaction pressure 3–8 MPa, and liquid hourly space velocity 0.2–3.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 400–800.

[0044] Optionally, the bio-oil is selected from waste cooking oil, swill oil, palm oil, soybean oil, rapeseed oil, palm oil, cottonseed oil, jatropha oil, peanut oil, tallow or lard, and / or natural oils.

[0045] Compared with the prior art, the present invention achieves at least one of the following beneficial effects:

[0046] (1) For the first time, a catalyst prepared by combining nickel metal nanoparticles and MCM-22 molecular sieve was applied to hydrocracking and isomerization reactions.

[0047] Furthermore, the prepared metal (nickel)-MCM-22 molecular sieve catalyst simultaneously possesses isomerization and cracking properties, overcoming the technical obstacle of existing catalysts that cannot simultaneously exhibit both isomerization and cracking performance. This is because this application uses a eutectic process to in-situ embed a specific amount of nickel metal nanoparticles into the MCM-22 molecular sieve, achieving nickel metal atom modification of the MCM-22 molecular sieve particle surface, eliminating some acidic centers, and thus obtaining a metal-MCM-22 molecular sieve catalyst that simultaneously possesses isomerization and cracking properties.

[0048] Furthermore, the selectivity of isomerization and cracking performance of the metal-MCM-22 molecular sieve catalyst can be adjusted by changing the nickel and molecular sieve content, thereby improving the flexibility of the entire production process. The ratio of biojet fuel and biodiesel can be flexibly adjusted according to market demand.

[0049] (2) The catalyst of this invention is a reduced catalyst, which does not require sulfidation before use and does not require sulfur replenishment during use. It will not affect the sulfur content of the product, nor will it generate sulfur-containing waste gas, thus avoiding environmental pollution. The catalyst prepared by this invention does not contain precious metals, and its production cost is much lower than that of precious metal catalysts. It is also more tolerant to raw materials.

[0050] (3) The catalyst prepared by the method of the present invention is unsupported and the active metal content is 2 to 3 times that of conventional supported catalysts. The nickel metal loading in the catalyst prepared by the present invention can be as high as 42%, exhibiting higher catalytic activity, and the reaction can be carried out at a lower temperature. Attached Figure Description

[0051] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0052] Figure 1 The scanning electron microscope (SEM) energy dispersive spectroscopy (EDS) spectrum of the metal-MCM-22 molecular sieve catalyst in Example 1 of this invention is shown.

[0053] Figure 2 The gas chromatogram of the liquid product obtained when the metal-MCM-22 molecular sieve catalyst of Example 2 of the present invention is applied to the hydrocracking and isomerization (260°C) of hydrocarbon-based biodiesel is shown.

[0054] Figure 3 A photograph of the metal-MCM-22 molecular sieve catalyst of Example 3 of the present invention is shown. Detailed Implementation

[0055] To more clearly illustrate the overall concept of the present invention, a detailed description will be provided below with reference to the accompanying drawings and examples.

[0056] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0057] Example 1

[0058] A nickel-based molecular sieve hydrocracking and isomerization catalyst, comprising, by mass fraction, 65% MCM-22 molecular sieve, 25% elemental nickel, and 10% γ-Al2O3.

[0059] The preparation method of nickel-based molecular sieve hydrocracking and isomerization catalyst includes the following steps:

[0060] S1: Dissolve the silicon source (silica sol), aluminum source (aluminum sulfate), sodium hydroxide, and template agent (hexamethyleneimine) in deionized water to obtain a viscous liquid. The feed ratio, calculated by the mass of oxides, is SiO2:Al2O3:Na2O:template agent:H2O = 60:1:30:10:4000. Then, perform hydrothermal treatment at 60℃ for 5 hours to obtain the MCM-22 molecular sieve precursor. Adjust the pH to 9.

[0061] S2: Nickel nitrate was added to the MCM-22 molecular sieve precursor, and ultrasonic crystallization was carried out at 150℃ and 300W for 4 days. The pH was adjusted to 8, and the mixture was filtered, washed and dried to obtain a Ni-MCM-22 molecular sieve composite with nickel metal nanoparticles embedded in it. The chemical composition of the feed material was calculated by the mass of oxides as SiO2:Al2O3:NiO:Na2O:template:H2O = 60:1:20:30:10:4000.

[0062] S3: The Ni-MCM-22 molecular sieve composite was added to a mixed solution of 0.15 mol / L hydrochloric acid and phosphoric acid (mass ratio 1:1) and treated at 60℃ for 6 hours. The acid-treated composite was washed until neutral, then dried and calcined at 450℃ for 4 hours to obtain the Ni-MCM-22 molecular sieve catalyst. The properties of the Ni-MCM-22 molecular sieve catalyst are as follows: BET specific surface area is 472 m². 2 The total pore volume is 0.81 cm³. 3 / g, SiO2:Al2O3 (molar ratio) = 66.

[0063] S4: Take 30g Ni-MCM-22 molecular sieve catalyst, 5g aluminum hydroxide dry adhesive powder, 2g dilute nitric acid solution and 10g guar gum powder, then mix, shape, dry, calcine at 500℃ for 4 hours, and reduce at 500℃ for 4 hours to obtain a cracking and isomerization catalyst with a nickel content of 25wt%.

[0064] Example 2

[0065] A nickel-based molecular sieve hydrocracking and isomerization catalyst, comprising, by mass fraction, 65% MCM-22 molecular sieve, 25% elemental nickel, and 10% γ-Al2O3.

[0066] S1: Dissolve silicon source (kaolin), aluminum source (aluminum chloride), sodium hydroxide and template agent (hexamethyleneimine) in deionized water to obtain a viscous liquid. The feed ratio, calculated by the mass of oxides, is SiO2:Al2O3:Na2O:template agent:H2O = 60:1:30:10:4000. Then, hydrothermally treat at 30℃ for 5 hours to obtain the MCM-22 molecular sieve precursor, and adjust the pH to 10.5.

[0067] S2: Nickel sulfate was added to the MCM-22 molecular sieve precursor, and ultrasonic crystallization was carried out at 130℃ and 300W for 6 days. The pH was adjusted to 12, and the mixture was filtered, washed and dried to obtain a Ni-MCM-22 molecular sieve composite with nickel metal nanoparticles embedded in it. The chemical composition of the feed material was calculated by the mass of oxides as SiO2:Al2O3:NiO:Na2O:template:H2O = 60:1:20:30:10:4000.

[0068] S3: The Ni-MCM-22 molecular sieve composite was added to a mixed solution of 0.15 mol / L hydrochloric acid and phosphoric acid (mass ratio 1:1) and treated at 50°C for 6 hours. The acid-treated composite was washed until neutral, then dried and calcined at 500°C for 4 hours to obtain the Ni-MCM-22 molecular sieve catalyst. The properties of the Ni-MCM-22 molecular sieve catalyst are as follows: BET specific surface area is 289 m². 2 The total pore volume is 0.53 cm³. 3 / g, SiO2:Al2O3 (molar ratio) = 67.

[0069] In step S4: Take 30g of Ni-MCM-22 molecular sieve catalyst, 5g of aluminum hydroxide dry adhesive powder, 2g of dilute nitric acid solution and 10g of guar gum powder, then mix, shape, dry, calcine at 500℃ for 4 hours, and reduce at 500℃ for 4 hours to obtain a cracking and isomerization catalyst with a nickel content of 25wt%.

[0070] Example 3

[0071] A nickel-based molecular sieve hydrocracking and isomerization catalyst, comprising, by mass fraction, 65% MCM-22 molecular sieve, 25% elemental nickel, and 10% γ-Al2O3.

[0072] S1: Dissolve silicon source (sodium silicate), aluminum source (sodium aluminate), sodium hydroxide, and template agent (hexamethyleneimine) in deionized water to obtain a viscous liquid. The feed ratio, calculated by the mass of oxides, is SiO2:Al2O3:Na2O:template agent:H2O = 60:1:30:10:4000. Then, perform hydrothermal treatment at 80℃ for 5 hours to obtain the MCM-22 molecular sieve precursor, and adjust the pH to 13.

[0073] S2: Nickel acetate was added to the MCM-22 molecular sieve precursor, and ultrasonic crystallization was carried out at 170℃ and 300W for 3 days. The pH was adjusted to 9.5, and after filtration, washing and drying, a Ni-MCM-22 molecular sieve composite with nickel metal nanoparticles embedded was obtained. The chemical composition of the feed material was calculated by the mass of oxides as SiO2:Al2O3:NiO:Na2O:template:H2O = 60:1:20:30:10:4000.

[0074] S3: The Ni-MCM-22 molecular sieve composite was added to a mixed solution of 0.15 mol / L hydrochloric acid and phosphoric acid (mass ratio 1:1) and treated at 40℃ for 6 hours. The acid-treated composite was washed until neutral, then dried and calcined at 600℃ for 4 hours to obtain the Ni-MCM-22 molecular sieve catalyst. The properties of the Ni-MCM-22 molecular sieve catalyst are as follows: BET specific surface area is 314 m². 2 The total pore volume is 0.62 cm³. 3 / g, SiO2:Al2O3 (molar ratio) = 65. The obtained catalyst sample is shown below. Figure 3 .

[0075] In step S4: Take 30g of Ni-MCM-22 molecular sieve catalyst, 5g of aluminum hydroxide dry adhesive powder, 2g of dilute nitric acid solution and 10g of guar gum powder, then mix, shape, dry, calcine at 500℃ for 4 hours, and reduce at 500℃ for 4 hours to obtain a cracking and isomerization catalyst with a nickel content of 25wt%.

[0076] Example 4

[0077] A nickel-based molecular sieve hydrocracking and isomerization catalyst, comprising, by mass fraction, 52% MCM-22 molecular sieve, 38% elemental nickel, and 10% γ-Al2O3.

[0078] Based on Example 1, the main difference is that in step S2, the chemical composition of the feed material, calculated by the mass of the oxide, is SiO2:Al2O3:NiO:Na2O:template agent:H2O = 60:1:30:40:20:3500.

[0079] In step S3: The properties of the Ni-MCM-22 molecular sieve catalyst are as follows: BET specific surface area is 285 m². 2 The total pore volume is 0.46 cm³. 3 / g, SiO2:Al2O3 (molar ratio) = 64.

[0080] In step S4: Take 30g of Ni-MCM-22 molecular sieve catalyst, 5g of aluminum hydroxide dry adhesive powder, 2g of dilute nitric acid solution and 10g of guar gum powder, then mix, shape, dry, calcine at 500℃ for 4 hours, and reduce at 500℃ for 4 hours to obtain a cracking and isomerization catalyst with a nickel content of 38wt%.

[0081] Example 5

[0082] A nickel-based molecular sieve hydrocracking and isomerization catalyst, comprising, by mass fraction, 71% MCM-22 molecular sieve, 19% elemental nickel, and 10% γ-Al2O3.

[0083] Based on Example 1, the main difference is that in step S2, the chemical composition of the feed material, calculated by the mass of the oxide, is SiO2:Al2O3:NiO:Na2O:template agent:H2O = 60:1:15:25:25:3000.

[0084] In step S3: The properties of the Ni-MCM-22 molecular sieve catalyst are as follows: BET specific surface area is 348 m². 2 The total pore volume is 0.39 cm³. 3 / g, SiO2:Al2O3 (molar ratio) = 68.

[0085] In step S4: Take 30g of Ni-MCM-22 molecular sieve catalyst, 5g of aluminum hydroxide dry adhesive powder, 2g of dilute nitric acid solution and 10g of guar gum powder, then mix, shape, dry, calcine at 500℃ for 4 hours, and reduce at 500℃ for 4 hours to obtain a cracking and isomerization catalyst with a nickel content of 19wt%.

[0086] Example 6

[0087] A nickel-based molecular sieve hydrocracking and isomerization catalyst, comprising, by mass fraction, 64% MCM-22 molecular sieve, 26% elemental nickel, and 10% γ-Al2O3.

[0088] The main difference from Example 1 is that,

[0089] In step S3: the Ni-MCM-22 molecular sieve composite is added to a mixed solution of 0.15 mol / L sodium hydroxide and ammonia water, with a mass ratio of sodium hydroxide to ammonia water of 1:1, and treated at 60°C for 6 hours; the alkali-treated composite is washed until neutral, and then dried and calcined at 450°C for 4 hours to obtain the Ni-MCM-22 molecular sieve catalyst.

[0090] The properties of the Ni-MCM-22 molecular sieve catalyst are as follows: BET specific surface area is 372m². 2 The total pore volume is 0.34 cm³. 3 / g, SiO2:Al2O3 (molar ratio) = 58.

[0091] In step S4: Take 30g of Ni-MCM-22 molecular sieve catalyst, 2g of aluminum hydroxide dry adhesive powder, 2g of dilute nitric acid solution and 10g of guar gum powder, then mix, shape, dry, calcine at 500℃ for 4 hours, and reduce at 500℃ for 4 hours to obtain a cracking and isomerization catalyst with a nickel content of 26wt%.

[0092] Example 7

[0093] A nickel-based molecular sieve hydrocracking and isomerization catalyst, comprising, by mass fraction, 66% MCM-22 molecular sieve, 24% elemental nickel, and 10% γ-Al2O3.

[0094] The main difference from Example 1 is that,

[0095] In step S3: the Ni-MCM-22 molecular sieve complex is added to a mixed solution of 0.15 mol / L hydrochloric acid and phosphoric acid, with a mass ratio of hydrochloric acid to phosphoric acid of 1:1, and treated at 60°C for 6 hours; the acid-treated complex is washed until neutral and then dried.

[0096] The Ni-MCM-22 molecular sieve composite was then added to a mixed solution of 0.15 mol / L sodium hydroxide and ammonia water, with a mass ratio of sodium hydroxide to ammonia water of 1:1, and treated at 60°C for 6 hours. The alkali-treated composite was washed until neutral, and then dried and calcined at 450°C for 4 hours to obtain the Ni-MCM-22 molecular sieve catalyst.

[0097] The properties of the Ni-MCM-22 molecular sieve catalyst are as follows: BET specific surface area is 295 m². 2 The total pore volume is 0.45 cm³. 3 / g, SiO2:Al2O3 (molar ratio) = 64.

[0098] In step S4: Take 30g of Ni-MCM-22 molecular sieve catalyst, 5g of aluminum hydroxide dry adhesive powder, 2g of dilute nitric acid solution and 10g of guar gum powder, then mix, shape, dry, calcine at 500℃ for 4 hours, and reduce at 500℃ for 4 hours to obtain a cracking and isomerization catalyst with a nickel content of 24wt%.

[0099] Example 8

[0100] A nickel-based molecular sieve hydrocracking and isomerization catalyst, comprising, by mass fraction, 65% MCM-22 molecular sieve, 25% elemental nickel, and 10% γ-Al2O3.

[0101] The main difference from Example 1 is that,

[0102] In step S3: the Ni-MCM-22 molecular sieve composite is added to a mixed solution of 0.15 mol / L sodium hydroxide and ammonia, with a mass ratio of sodium hydroxide to ammonia of 1:1, and treated at 60°C for 6 hours; the alkali-treated composite is washed until neutral and then dried.

[0103] The Ni-MCM-22 molecular sieve composite was then added to a mixed solution of 0.15 mol / L hydrochloric acid and phosphoric acid (mass ratio of hydrochloric acid to phosphoric acid: 1:1) and treated at 60 °C for 6 hours. The acid-treated composite was washed until neutral, then dried and calcined at 450 °C for 4 hours to obtain the Ni-MCM-22 molecular sieve catalyst.

[0104] The properties of the Ni-MCM-22 molecular sieve catalyst are as follows: BET specific surface area is 286 m². 2 The total pore volume is 0.42 cm³. 3 / g, SiO2:Al2O3 (molar ratio) = 65.

[0105] In step S4: Take 30g of Ni-MCM-22 molecular sieve catalyst, 5g of aluminum hydroxide dry adhesive powder, 2g of dilute nitric acid solution and 10g of guar gum powder, then mix, shape, dry, calcine at 500℃ for 4 hours, and reduce at 500℃ for 4 hours to obtain a cracking and isomerization catalyst with a nickel content of 25wt%.

[0106] Example 9

[0107] A nickel-based molecular sieve hydrocracking and isomerization catalyst, comprising, by mass fraction, 66% MCM-22 molecular sieve, 24% elemental nickel, and 10% γ-Al2O3.

[0108] The main difference from Example 1 is that,

[0109] In step S2: Nickel nitrate is added to the MCM-22 molecular sieve precursor, and the mixture is mechanically stirred and crystallized for 4 days at 150℃ and 120 rpm. The pH is adjusted to 8, and the mixture is then filtered, washed, and dried to obtain a Ni-MCM-22 molecular sieve composite with nickel metal nanoparticles embedded in it. The chemical composition of the feed material, calculated by the mass of oxides, is SiO2:Al2O3:NiO:Na2O:template:H2O = 60:1:20:30:10:4000.

[0110] In step S3: The properties of the Ni-MCM-22 molecular sieve catalyst are as follows: BET specific surface area is 226 m². 2 The total pore volume is 0.32 cm³. 3 / g, SiO2:Al2O3 (molar ratio) = 65.

[0111] In step S4: Take 30g of Ni-MCM-22 molecular sieve catalyst, 5g of aluminum hydroxide dry adhesive powder, 2g of dilute nitric acid solution and 10g of guar gum powder, then mix, shape, dry, calcine at 500℃ for 4 hours, and reduce at 500℃ for 4 hours to obtain a cracking and isomerization catalyst with a nickel content of 24wt%.

[0112] Comparative Example 1

[0113] A nickel-based molecular sieve hydrocracking and isomerization catalyst, comprising, by mass fraction, 65% MCM-22 molecular sieve, 25% elemental nickel, and 10% γ-Al2O3.

[0114] The catalyst preparation method includes the following steps:

[0115] S1: A viscous liquid was obtained by dissolving a silicon source (silica sol), an aluminum source (aluminum sulfate), sodium hydroxide, and a template agent (hexamethyleneimine) in deionized water. The chemical composition of the feed, calculated by the mass of the oxides, was SiO2:Al2O3:Na2O:template agent:H2O = 60:1:30:10:4000. The precursor was then hydrothermally treated at 60℃ for 5 hours to obtain the MCM-22 molecular sieve precursor, and the pH was adjusted to 9.

[0116] S2: The MCM-22 molecular sieve precursor was ultrasonically crystallized at 150℃ and 300W for 4 days, and the pH was adjusted to 8. After filtration, washing and drying, the MCM-22 molecular sieve was obtained.

[0117] S3: Add MCM-22 molecular sieve to a mixed solution of 0.15 mol / L hydrochloric acid and phosphoric acid, with a mass ratio of 1:1, and treat at 60℃ for 6 hours; wash the acid-treated complex until neutral, then dry and calcine at 500℃ for 4 hours to obtain MCM-22 molecular sieve.

[0118] S4: Take 30g of MCM-22 molecular sieve, 5g of aluminum hydroxide dry adhesive powder, 2g of dilute nitric acid solution and 10g of guar gum powder, then mix, shape, dry and calcine at 500℃ for 4 hours to obtain molecular sieve carrier.

[0119] S5: Prepare an aqueous solution of nickel nitrate, and load nickel nitrate onto an MCM-22 molecular sieve support using an equal-volume impregnation method. After drying, calcination at 500℃ for 4 hours, and reduction at 500℃ for 4 hours, a cracking and isomerization catalyst Ni / MCM-22 with a nickel loading of 25wt% is obtained. The properties of the Ni / MCM-22 molecular sieve catalyst are as follows: BET specific surface area is 316 m². 2 The total pore volume is 0.30 cm³. 3 / g, SiO2:Al2O3 (molar ratio) = 66.

[0120] Comparative Example 2

[0121] A nickel-based molecular sieve hydrocracking and isomerization catalyst, comprising, by mass fraction, 89.5% MCM-22 molecular sieve, 0.5% elemental platinum, and 10% γ-Al2O3.

[0122] Based on Example 1, the main difference is that,

[0123] In step S5: A chloroplatinic acid aqueous solution was prepared, and the chloroplatinic acid was loaded onto the support using an equal-volume impregnation method. After drying, calcination at 400℃ for 4 hours, and reduction at 400℃ for 4 hours, a cracking and isomerization catalyst Pt / MCM-22 with a Pt loading of 0.5 wt% was obtained. The properties of the Pt / MCM-22 molecular sieve catalyst are as follows: BET specific surface area is 319 m². 2 The total pore volume is 0.33 cm³. 3 / g, SiO2:Al2O3 (molar ratio) = 66.

[0124] Comparative Example 3

[0125] A nickel-based molecular sieve hydrocracking and isomerization catalyst, comprising, by mass fraction, 67% MCM-22 molecular sieve, 23% elemental nickel, and 10% γ-Al2O3.

[0126] S1: A viscous liquid was obtained by dissolving a silicon source (silica sol), an aluminum source (aluminum sulfate), sodium hydroxide, a template agent (hexamethyleneimine), and a nickel source (nickel nitrate) in deionized water. The chemical composition of the feed, calculated by the mass of oxides, was SiO2:Al2O3:NiO:Na2O:template agent:H2O = 60:1:20:30:10:4000. The mixture was crystallized for 4 days under ultrasonic assistance at 150℃ and 300W power. The pH was adjusted to 8, and the mixture was then filtered, washed, and dried to obtain a metal-MCM-22 molecular sieve composite with nickel metal nanoparticles embedded in it.

[0127] S2: The metal-MCM-22 molecular sieve composite was added to a mixed solution of 0.15 mol / L hydrochloric acid and phosphoric acid (mass ratio 1:1) and treated at 60℃ for 6 hours. The acid-treated composite was washed until neutral, then dried and calcined at 450℃ for 4 hours to obtain the metal-MCM-22 molecular sieve catalyst. The properties of the metal-MCM-22 molecular sieve catalyst are as follows: BET specific surface area is 241 m². 2 The total pore volume is 0.28 cm³. 3 / g, SiO2:Al2O3 (molar ratio) = 69.

[0128] S3: Take 30g of metal-MCM-22 molecular sieve catalyst, 5g of aluminum hydroxide dry adhesive powder, 2g of dilute nitric acid solution and 10g of guar gum powder, then mix, shape, dry, calcine at 500℃ for 4 hours, and reduce at 500℃ for 4 hours to obtain a cracking and isomerization catalyst with a nickel content of 23wt%.

[0129] Comparative Example 4

[0130] A nickel-based molecular sieve hydrocracking and isomerization catalyst, comprising, by mass fraction, 65% MCM-22 molecular sieve, 25% elemental iron, and 10% γ-Al2O3.

[0131] The difference from Example 1 is that,

[0132] In step S2: replace the nickel salt with an iron salt (ferric nitrate), and the rest is the same as in Example 1.

[0133] In step S3: The properties of the Fe-MCM-22 molecular sieve catalyst are as follows: BET specific surface area is 376 m². 2 The total pore volume is 0.52 cm³. 3 / g, SiO2:Al2O3 (molar ratio) = 66.

[0134] In step S4: Take 30g of Fe-MCM-22 molecular sieve, 5g of aluminum hydroxide dry adhesive powder, 2g of dilute nitric acid solution and 10g of guar gum powder, then mix, shape, dry, calcine at 500℃ for 4 hours, and reduce at 500℃ for 4 hours to obtain a cracking and isomerization catalyst with an iron content of 25wt%.

[0135] Comparative Example 5

[0136] A nickel-based molecular sieve hydrocracking and isomerization catalyst, comprising, by mass fraction, 65% ZSM-22 molecular sieve, 25% elemental nickel, and 10% γ-Al2O3.

[0137] The difference from Example 1 is that the molecular sieve is different; ZSM-22 molecular sieve is used.

[0138] In step S1: the template agent hexamethyleneimine is replaced with hexamethylenediamine, and the rest is the same as in Example 1, to obtain the ZSM-22 molecular sieve precursor.

[0139] In step S3: Ni-ZSM-22 molecular sieve catalyst was obtained, prepared using the same process as in Example 1. The properties of the Ni-ZSM-22 molecular sieve catalyst are as follows: BET specific surface area is 366 m². 2 The total pore volume is 0.57 cm³. 3 / g, SiO2:Al2O3 (molar ratio) = 66.

[0140] In step S4: Take 30g of Ni-ZSM-22 molecular sieve, 5g of aluminum hydroxide dry adhesive powder, 2g of dilute nitric acid solution and 10g of guar gum powder, then mix, shape, dry, calcine at 500℃ for 4 hours, and reduce at 500℃ for 4 hours to obtain a cracking and isomerization catalyst with a nickel content of 25wt%.

[0141] Experimental Example 1

[0142] The catalysts prepared in the examples and comparative examples were loaded into a high-pressure fixed-bed reactor and, after being sealed, treated at 200°C for 4 hours under a normal hydrogen atmosphere to remove adsorbed water and other gaseous impurities from the catalyst. Then, the hydrogen pressure in the reactor was increased to 4 MPa, and after the tail gas flow rate after the back pressure valve stabilized, the reactor temperature was programmed to 260°C. The isomerization reaction was then initiated with a volume hourly space velocity (VHSV) of 1.5 h⁻¹. -1 The hydrogen-to-oil volume ratio is 800:1. The raw material used in the reaction is waste cooking oil that has been hydrogenated and deoxygenated to obtain C2O3. 15 -C 18 A mixture of straight-chain alkanes, with a pour point of 17°C and a sulfur content of 2 ppmw. Performance tests were conducted, and the results are shown in Table 1.

[0143] The stability in the table below represents the time during which the catalytic performance of the catalyst remains essentially unchanged during the catalytic reaction in a high-pressure fixed-bed reactor.

[0144] Table 1. Catalytic performance of bio-oils on different catalysts and properties of the resulting products (reaction temperature 260℃)

[0145]

[0146] Continued from Table 1

[0147]

[0148] Continued from Table 1

[0149]

[0150] As shown in Table 1, when the nickel-based molecular sieve catalyst of this invention is applied to the hydrocracking and isomerization of hydrocarbon-based biodiesel, it achieves ideal results at relatively low reaction temperatures, with a liquid yield of not less than 95%, a product pour point not higher than -20°C, a cracking rate of not less than 38%, and an isomerization rate of not less than 42%. Comparing Examples 1 and 2, 3, 4, and 5, changes in metal content significantly affect the catalyst's performance (activity, yield, cracking rate, isomerization rate, and stability). With increasing nickel content, the catalyst activity significantly improves; however, excessive loading of metallic nickel affects the pore structure, acid properties, and nickel metal dispersion of the molecular sieve, thereby reducing the cracking rate and isomerization rate of the feedstock.

[0151] Comparing Examples 1 and 6, 7, and 8, acid-base treatment significantly affects the catalyst's structure and reaction performance (activity, yield, cracking rate, isomerization rate, and stability). Acid-base treatment also partially removes aluminum and silicon from the molecular sieve, forming more mesoporous structures, which facilitates reaction diffusion and thus improves catalyst activity. Compared to alkali treatment, acid-treated catalysts show significantly improved cracking and isomerization rates. This is because acid treatment removes highly aggregated and poorly active nickel metal, resulting in highly dispersed nickel metal.

[0152] Compared with Example 1 and Example 9, the molecular sieve catalyst obtained by ultrasonic-assisted crystallization is superior to the molecular sieve catalyst obtained by mechanical stirring-assisted crystallization in terms of activity, cracking rate and isomerization rate.

[0153] Compared with Example 1, the catalyst prepared by the conventional impregnation method has a lower metal dispersion and forms a large amount of nickel metal with a high degree of aggregation and poor activity. In addition, the excessive metal will cover a large number of acidic centers on the surface of the molecular sieve support, resulting in a significant decrease in catalyst activity, cracking, isomerization and stability.

[0154] Compared to Comparative Example 2 and Example 1, the non-precious metal catalyst prepared by this invention exhibits a relatively higher feed conversion rate compared to precious metal catalysts. Although its cracking performance is lower, its product yield is higher. The non-precious metal catalyst prepared by this invention can achieve effects comparable to those of precious metal catalysts.

[0155] Compared with Comparative Example 3 and Example 1, and compared with direct crystallization after mixing all materials, the non-precious metal catalyst prepared by the precursor method of the present invention exhibits relatively higher feed conversion rate, yield, cracking rate, isomerization rate and stability.

[0156] Compared with Comparative Example 4 and Example 1, and compared with Fe-MCM-22, the Ni-MCM-22 catalyst used in this invention exhibits higher feed conversion rate, yield, cracking rate and isomerization rate.

[0157] Compared with Comparative Example 5 and Example 1, and compared with Ni-ZSM-22, the Ni-MCM-22 catalyst used in this invention exhibits higher feed conversion rate, yield, cracking rate, isomerization rate and stability, which is attributed to the unique layered structure and abundant mesoporous structure of MCM-22 molecular sieve.

[0158] Experimental Example 2

[0159] The catalysts prepared in the examples and comparative examples were loaded into a high-pressure fixed-bed reactor and, after being sealed, treated at 200°C for 4 hours under a normal hydrogen atmosphere to remove adsorbed water and other gaseous impurities from the catalyst. Then, the hydrogen pressure in the reactor was increased to 4 MPa, and after the tail gas flow rate after the back pressure valve stabilized, the reactor temperature was programmed to 300°C. The isomerization reaction was then initiated with a volume hourly space velocity (VHSV) of 1.5 h⁻¹. -1 The hydrogen-to-oil volume ratio is 800:1. The reactant used in the reaction is gutter oil that has undergone hydrodeoxygenation to obtain C2. 15 -C 18 A mixture of straight-chain alkanes, with a pour point of 15°C and a sulfur content of 2 ppmw. Performance tests were conducted, and the results are shown in Table 2.

[0160] The stability in the table below represents the time during which the catalytic performance of the catalyst remains essentially unchanged during the catalytic reaction in a high-pressure fixed-bed reactor.

[0161] Table 2 Catalytic performance of bio-oils on different catalysts and properties of the resulting products (reaction temperature 300℃)

[0162]

[0163] Continued from Table 2

[0164]

[0165]

[0166] Continued from Table 2

[0167] Referring to Table 2, when the nickel-based molecular sieve catalyst of this invention is applied to the hydrocracking and isomerization of hydrocarbon-based biodiesel, at relatively high reaction temperatures (e.g., 300°C), the liquid yield is not less than 85%, the pour point is not higher than -31°C, the cracking rate is not less than 61%, and the isomerization rate is not less than 52%. Increasing the reaction temperature can improve the catalyst's reactivity and the cracking and isomerization rates of n-alkanes, but high temperatures will significantly reduce the product yield and generate more gas. Therefore, for the same catalyst, a moderate reaction temperature can yield more of the target product. The source of the straight-chain alkane feedstock has little effect on the reaction process.

[0168] refer to Figure 1 The image shows a scanning electron microscope (SEM) energy dispersive spectroscopy (EDS) spectrum of the metal-MCM-22 molecular sieve catalyst in Example 1 of this application. As can be seen from the image, in the composite catalyst prepared by in-situ embedding, metallic nickel is uniformly dispersed inside the molecular sieve, which can provide more metal active centers and is beneficial to the activation of CH bonds in the raw material molecules.

[0169] refer to Figure 2 The figure shows a gas chromatogram of the liquid product obtained using the metal-MCM-22 molecular sieve catalyst in Example 2 of this application. As can be seen from the figure, the product consists of normal and isoalkanes with different carbon numbers, concentrated in the C8–C9 range. 16 Based on the jet fuel composition and the pour point of the products in Table 2, it can be seen that the nickel-based molecular sieve catalyst prepared in this invention exhibits excellent cracking and isomerization properties, making it very suitable for the production of bio-jet fuel products.

[0170] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A nickel-based molecular sieve hydrocracking and isomerization catalyst characterized by, The nickel-based molecular sieve hydrocracking and isomerization catalyst comprises 30-80% of MCM-22 molecular sieve, 15-45% of nickel metal, and the rest of γ-Al2O3, and the total mass fraction of the MCM-22 molecular sieve, the nickel metal and the γ-Al2O3 is 100% by mass fraction; The preparation method of the nickel-based molecular sieve hydrocracking and isomerization catalyst comprises the following steps: S1: preparing MCM-22 molecular sieve precursor and adjusting pH to 9-13; S2: in-situ embedding nickel metal nanoparticles into the MCM-22 molecular sieve precursor obtained in step S1 and adjusting pH to 8-12 to obtain a metal-MCM-22 molecular sieve composite with high metal loading; S3: treating the metal-MCM-22 molecular sieve composite obtained in step S2 with an acid solution and / or an alkali solution, and then sequentially filtering, washing with water, drying, and calcining to obtain a metal-MCM-22 molecular sieve catalyst; S4: adding aluminum hydroxide dry gel powder, dilute nitric acid solution and sesbania powder to the metal-MCM-22 molecular sieve catalyst obtained in step S3, and then kneading, shaping, drying, calcining, and reducing to obtain a nickel-based molecular sieve hydrocracking and isomerization catalyst with a metal loading of 6-42 wt%; The preparation method of the MCM-22 molecular sieve precursor in step S1 comprises the following steps: dissolving a silicon source, an aluminum source, sodium hydroxide and a template agent in deionized water to obtain a viscous liquid, and hydrothermally treating the viscous liquid at 30-80°C to obtain the MCM-22 molecular sieve precursor; wherein, calculated by the mass of oxides, the chemical composition of the viscous liquid is SiO2:Al2O3:Na2O:template agent:H2O=(20-80):(0.5-2):(10-50):(5-30):(1000-5000); The preparation method of the metal-MCM-22 molecular sieve composite in step S2 comprises the following steps: adding a nickel salt to the MCM-22 molecular sieve precursor, and performing a crystallization reaction at 120-180°C for 3-9 days to obtain a metal-MCM-22 molecular sieve composite with nickel metal nanoparticles embedded therein; the crystallization reaction process further comprises any one of ultrasonic assistance, mechanical stirring, and no mechanical stirring; and the chemical composition of the raw materials is SiO2:Al2O3:NiO:Na2O:template agent:H2O=(20-80):(0.5-2):(5-35):(10-50):(5-30):(1000-5000) by mass of oxides.

2. The nickel-based molecular sieve hydrocracking and isomerization catalyst of claim 1, wherein, The preparation method of the metal-MCM-22 molecular sieve catalyst in step S3 comprises the following steps: treating the metal-MCM-22 molecular sieve composite with an acid solution at a temperature of 40-70°C, and then sequentially filtering, washing with water, drying, and calcining at 450-600°C to obtain the metal-MCM-22 molecular sieve catalyst; and / or the metal-MCM-22 molecular sieve composite is treated with an alkali solution at a temperature of 50-80℃, and then the treated material is sequentially filtered, washed with water, dried, and calcined at 450-600℃ to obtain the metal-MCM-22 molecular sieve catalyst.

3. The nickel-based molecular sieve hydrocracking and isomerization catalyst of claim 1, wherein, The metal-MCM-22 molecular sieve catalyst obtained in step S4 has the following properties: SiO2:Al2O3 molar ratio = 15-80.

4. The nickel-based molecular sieve hydrocracking and isomerization catalyst of claim 1, wherein, The acid solution comprises one or more of hydrochloric acid, phosphoric acid, nitric acid, acetic acid, tartaric acid, and citric acid; the acid solution has a concentration of 0.1-0.5 mol / L. The alkali solution comprises one or more of sodium hydroxide, potassium hydroxide, and ammonia; the alkali solution has a concentration of 0.1-0.5 mol / L.

5. The nickel-based molecular sieve hydrocracking and isomerization catalyst of claim 4, wherein, The acid solution is a mixed acid solution of hydrochloric acid and phosphoric acid, and the mass ratio of hydrochloric acid to phosphoric acid is 1:

1.

6. The nickel-based molecular sieve hydrocracking and isomerization catalyst of claim 4, wherein, The alkali solution is a mixed alkali solution of sodium hydroxide and ammonia, and the mass ratio of sodium hydroxide to ammonia is 1:

1.

7. The nickel-based molecular sieve hydrocracking and isomerization catalyst of claim 1, wherein, The silicon source comprises one or two of silica sol, sodium silicate, kaolin, and white carbon black. The aluminum source comprises one or two of aluminum sulfate, aluminum nitrate, aluminum chloride, and sodium metaaluminate. The template agent is hexamethylene imine.

8. The nickel-based molecular sieve hydrocracking and isomerization catalyst of claim 1, wherein, The nickel salt comprises one or more of a nitrate, a nitrite, a sulfate, a chloride, an alkaline carbonate, and an acetate.

9. Use of a nickel-based molecular sieve hydrocracking and isomerization catalyst according to claim 1 in a hydroisomerization / cracking reaction of bio-based long chain paraffins, derived from a hydrodeoxygenation process of bio-oil, consisting of a mixture of linear paraffins with a carbon number in the range of C 15 ~C 18 and a sulfur content < 3 ppmw.

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