Mo-based poor oil slurry bed hydrocracking catalyst, preparation method and application method

Abstract

This invention discloses a molybdenum-based slurry-bed hydrocracking catalyst for inferior oil, its preparation method, and its application method. The preparation method includes: mixing slurry-bed hydrocracking tailings with naphtha obtained from the process, separating and removing oil from the tailings to obtain a solid residue; calcining in air to obtain a solid powder; dissolving each gram of solid powder in 2-6 ml of ammonia water under stirring conditions, controlling the dissolution temperature at 50-100°C and dissolving for 1-6 hours to obtain a first mixture; filtering to obtain a solution; and... Under stirring conditions, a methanol solution of zinc nitrate and dimethylimidazole was added to the solvent; the reaction was carried out at room temperature for 4–12 h to obtain a second mixture; the mixture was filtered to obtain a precipitate; the precipitate was dried at 60–150 °C for 1–12 h to prepare a ZIF-8 coated molybdenum salt catalyst precursor; the ZIF-8 coated molybdenum salt catalyst precursor was calcined at 400–800 °C for 1–6 h in an oxygen-free atmosphere to obtain a molybdenum-based low-quality oil slurry bed hydrocracking catalyst.

Description

Technical Field

[0001] This invention relates to the field of inferior oil processing technology, and in particular to a molybdenum-based slurry-bed hydrocracking catalyst for inferior oil, its preparation method, and its application method. Background Technology

[0002] For the increasing availability of low-quality crude oil resources characterized by high sulfur, high metal content, and high residual carbon, slurry-bed hydrocracking technology for low-quality oil is a suitable process technology that aligns with the current trend of efficient resource utilization. The key to the development of slurry-bed hydrocracking technology for low-quality oil lies in the continuous improvement of hydrocracking catalysts. Among them, highly dispersed catalysts can be effectively dispersed in heavy feedstocks, exhibiting excellent hydrocracking activity and the ability to inhibit condensation and coking, making them relatively ideal catalysts. However, the production cost of this type of catalyst is significantly affected by fluctuations in the market prices of metals such as molybdenum, tungsten, and nickel, and its preparation cost is relatively high. Furthermore, to maintain high hydrocracking activity, a certain concentration of catalyst needs to be continuously injected into the reaction system, leading to increased processing costs and hindering the process's economic advantages.

[0003] For example, Chinese patent CN201610804914.2 discloses the preparation of an active metal precursor by precipitating a soluble salt of Mo or W at 40-100°C, and then reacting it with C6~C6. 20 Oil-soluble catalysts are prepared by reacting organic acids. Chinese patent CN201410216485.8 discloses the preparation of oil-soluble catalysts by reacting reduced metals with organic amines. Chinese patent CN201510848631.3 discloses the preparation of oil-soluble catalysts by reacting metal salts with carboxylic acid organic compounds, alcohols, and sulfiding agents. Chinese patent CN01106013.1 discloses the preparation of oil-soluble catalysts by reacting Mo and W metals with benzopyrene and its derivatives. Summary of the Invention

[0004] To enrich process routes and increase the options available, this invention provides a molybdenum-based slurry-bed hydrocracking catalyst for inferior oil, its preparation method, and its application method.

[0005] In a first aspect, embodiments of the present invention provide a method for preparing a molybdenum-based slurry-bed hydrocracking catalyst for inferior oil, which may include:

[0006] After mixing the tailings of slurry bed hydrocracking with the naphtha produced by slurry bed hydrocracking, the oil in the tailings is separated to obtain solid residue.

[0007] The solid residue was calcined in air to obtain a solid powder;

[0008] The calcined solid powder was dissolved in 2-6 ml of ammonia water per gram of solid powder under stirring conditions, and the dissolution temperature was controlled at 50-100℃ for 1-6 hours to obtain the first mixture.

[0009] The first mixture is filtered to obtain a solution;

[0010] Under stirring conditions, a methanol solution of zinc nitrate and dimethylimidazole was added to the solution; and the mixture was reacted at room temperature for 4–12 h to obtain a second mixture.

[0011] The second mixture is filtered to obtain the precipitate in the second mixture;

[0012] The precipitate was dried at 60–150 °C for 1–12 h to prepare a ZIF-8-coated molybdenum salt catalyst precursor.

[0013] The ZIF-8-coated molybdenum salt catalyst precursor was calcined in an oxygen-free atmosphere at a calcination temperature of 400–800 °C for 1–6 h to obtain a molybdenum-based slurry bed hydrocracking catalyst for inferior oil.

[0014] Optionally, the molar ratio of zinc nitrate to molybdenum in the solution is 4–16:1, and the molar ratio of dimethylimidazole to zinc nitrate is 3–6:1.

[0015] Optionally, the method may further include: dissolving the calcined solid powder in 4-6 ml of ammonia water per gram of solid powder under stirring conditions, controlling the dissolution temperature at 70-90°C and dissolving for 2-4 hours to obtain a first mixture;

[0016] The first mixture is filtered to obtain a solution;

[0017] Under stirring conditions, a methanol solution of zinc nitrate and dimethylimidazole was added to the solution; and the mixture was reacted at room temperature for 4–6 h to obtain a second mixture.

[0018] The second mixture is filtered to obtain the precipitate in the second mixture;

[0019] The precipitate was dried at 95–120°C for 4–6 h to prepare a ZIF-8-coated molybdenum salt catalyst precursor.

[0020] The ZIF-8-coated molybdenum salt catalyst precursor was calcined in an oxygen-free atmosphere at a calcination temperature of 450–650 °C for 3–6 h to obtain a molybdenum-based slurry bed hydrocracking catalyst for inferior oil.

[0021] Optionally, the molar ratio of zinc nitrate to molybdenum in the solution is 5 to 10:1, and the molar ratio of dimethylimidazole to zinc nitrate is 4 to 6:1.

[0022] Optionally, the mass ratio of the petroleum naphtha to the slurry bed hydrocracking tailings is 1 to 6:1.

[0023] Optionally, the mass ratio of the petroleum naphtha to the slurry bed hydrocracking tailings is 1 to 2:1.

[0024] Optionally, the temperature at which the oil is separated from the tailings is 70–100°C.

[0025] Optionally, the temperature at which the oil is separated from the tailings is 70–90°C.

[0026] Optionally, the solid residue is calcined in air at a temperature of 400–800°C for 1–6 hours to obtain a solid powder.

[0027] Optionally, the solid residue is calcined in air at a temperature of 450–650°C for 2–4 hours to obtain a solid powder.

[0028] Secondly, embodiments of the present invention provide a molybdenum-based slurry-bed hydrocracking catalyst for inferior oil, wherein the molybdenum-based slurry-bed hydrocracking catalyst for inferior oil is prepared according to the preparation method of the molybdenum-based slurry-bed hydrocracking catalyst for inferior oil described in the first aspect.

[0029] Thirdly, embodiments of the present invention provide a method for applying a molybdenum-based slurry bed hydrocracking catalyst for inferior oil in the inferior oil processing technology, wherein the molybdenum-based slurry bed hydrocracking catalyst for inferior oil is uniformly mixed with diesel fraction produced by slurry bed hydrocracking at a volume ratio of 0.05 to 0.2:1 and then added to the inferior oil feedstock;

[0030] The molybdenum-based inferior oil slurry bed hydrocracking catalyst is prepared according to the preparation method of the molybdenum-based inferior oil slurry bed hydrocracking catalyst described in the first aspect.

[0031] Optionally, the amount of the molybdenum-based low-grade oil slurry-bed hydrocracking catalyst used is 200–1000 μg / g (calculated as metallic molybdenum), and the process conditions are: reaction pressure 10–20 MPa, reaction temperature 360–450 °C, and volume hourly space velocity 0.2–1.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 300–1000.

[0032] Optionally, the molybdenum-based low-quality oil slurry bed hydrocracking catalyst and diesel fraction are uniformly mixed at a volume ratio of 0.05 to 0.1:1 and then added to the low-quality oil feedstock.

[0033] Optionally, the amount of the molybdenum-based low-quality oil slurry-bed hydrocracking catalyst used is 300–600 μg / g (calculated as metallic molybdenum), and the process conditions are: reaction pressure 10–16 MPa, reaction temperature 390–420 °C, and volume hourly space velocity 0.2–0.5 h⁻¹. -1 The hydrogen-to-oil volume ratio is 300–500.

[0034] The beneficial effects of the above-described technical solutions provided in the embodiments of the present invention include at least the following:

[0035] This invention provides a molybdenum-based slurry-bed hydrocracking catalyst for low-quality oil, its preparation method, and its application method. The preparation method has advantages such as simple process, mild conditions, high molybdenum recovery rate, and ease of low-cost industrial application. The prepared molybdenum-based catalyst exhibits excellent hydrogenation performance and is particularly suitable for low-cost slurry-bed hydrocracking processes of low-quality oils with high metal content, high carbon residue, and high sulfur content.

[0036] Specifically, the preparation method of the molybdenum-based inferior oil slurry bed hydrocracking catalyst and the prepared catalyst in the embodiments of the present invention have the following beneficial effects:

[0037] (1) Mixing the slurry bed hydrocracking tailings with the naphtha produced by the unit is beneficial to the efficient separation of oil and metal-rich solid residues in the tailings.

[0038] (2) The waste catalyst contained in the solid residue can be efficiently recovered by roasting and ammonia dissolution.

[0039] (3) The active metal molybdenum salt can be effectively inhibited by coating the metal framework material, and the active component molybdenum is dispersed in a single atom on a carbon support catalyst. It has excellent hydrogenation activity and coking suppression performance, and realizes the efficient reuse of molybdenum-based catalyst.

[0040] (4) The slurry bed catalyst prepared by the present invention is dispersed and carried by the self-produced diesel fraction, and then injected into the inferior residue oil feedstock. Since the diesel fraction used as a carrier or dispersant comes from the inferior residue oil, it is more conducive to the dispersion of the catalyst in the feedstock in terms of the original factors of hydrocarbon composition, which is beneficial to the high dispersion and efficient utilization of the catalyst.

[0041] (5) The present invention provides a method for preparing molybdenum-based slurry-bed hydrocracking catalyst from slurry-bed hydrocracking tailings and its application method. It has the advantages of simple process, mild conditions, high molybdenum recovery rate, online recovery of active metal and preparation of catalyst or offline recovery of active metal and preparation of catalyst, and low-cost industrial application.

[0042] (6) The molybdenum-based catalyst prepared by the present invention has the characteristics of low addition amount and simple application, and is suitable for slurry bed hydrocracking process of high metal, high carbon residue, high sulfur and inferior oil.

[0043] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings.

[0044] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0045] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0046] Figure 1 This is a schematic diagram of the preparation method and application process of the molybdenum-based inferior oil slurry bed hydrocracking catalyst provided in the embodiments of the present invention. Detailed Implementation

[0047] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0048] The inventors summarized reported oil-soluble catalysts, identifying them primarily as precursors of organic acid salts, organometallic compounds or complexes, and metal salts of organic amines. While these oil-soluble catalysts exhibit excellent hydrocracking performance, the precursors require the addition of sulfiding agents to convert them into catalytically active metal sulfides. This process, due to the difficulty of sulfidation, generally results in larger particle sizes of the final sulfides, reducing catalytic hydrogenation activity, leading to higher additive amounts, and increasing operating costs. Therefore, the preparation of highly active, highly dispersed, low-quality oil slurry-bed hydrocracking catalysts is a pressing technical problem that needs to be solved in this field.

[0049] Currently, slurry-bed hydrocracking processes for low-quality heavy feedstocks typically produce 1–10 wt% hydrocracking tailings. This fraction is enriched with impurities such as coke, deactivated catalyst, and metals generated during the reaction. Achieving high-value utilization of solid impurities and valuable metals in hydrocracking tailings is crucial to the economic viability of slurry-bed hydrocracking technology. Simultaneously, with increasingly stringent environmental regulations, the harmless treatment of industrial waste has attracted significant attention. If the solids in slurry-bed hydrocracking tailings are not treated, they will inevitably pollute the environment. Furthermore, these solids contain high-value active metals, and efficient recycling will generate substantial economic and social benefits. Therefore, the resource utilization of hydrocracking tailings has always been a major concern for researchers.

[0050] To address the aforementioned technical problems, some technical solutions have been proposed in the prior art. For example, the technical solution disclosed in application number 20171080154.1, entitled "Method for Recycling Oil-Soluble Molybdenum-Based Slurry Bed Hydrocracking Catalyst," is as follows: Waste catalyst is subjected to roasting, ammonia dissolution, and sulfidation processes to obtain molybdenum sulfide metal salts. Then, the molybdenum sulfide metal salts are reacted with organic acids to prepare a precursor for an oil-soluble molybdenum-based catalyst. This precursor undergoes self-sulfidation decomposition in low-quality oil to form a nanoscale dispersed catalyst, ultimately achieving the reuse of the waste catalyst. The inventors have found the following drawbacks of this technical solution: Firstly, the method for obtaining the slurry bed waste catalyst used as the catalyst preparation raw material is not clearly explained; secondly, there is a technical bottleneck in the efficient separation of the waste catalyst from the slurry bed hydrocracking tailings. Furthermore, this method requires the addition of sulfiding agents and organic acids to prepare a highly dispersed oil-soluble slurry bed hydrocracking catalyst. Because a large amount of valuable sulfiding agents and organic acids are required, the preparation cost is relatively high compared to fresh catalyst.

[0051] For example, the technical solution disclosed in application number 20171124760.0, entitled "Recovery and Application of Metals in Suspended Bed or Slurry Bed Hydrocracking Residue", is as follows: Molybdenum or molybdenum and nickel metal contained in suspended bed or slurry bed hydrocracking residue is recovered by digestion reaction using different digestion solutions. Then, a reducing agent is added for reduction reaction, and after washing, a slurry bed catalyst is obtained and injected into the feedstock system to realize the recycling of the catalyst. The inventors discovered that this technical solution first requires the use of two types of high-value digestion solutions: one is a mixture containing water, alcohol, and amine, where the alcohol and amine include various organic reagents; the other is an alkaline or acidic digestion solution containing reagents such as urea, ammonia, sulfuric acid, ethanol, and water. Secondly, this method consumes a large amount of reducing agents, including inorganic sulfides such as sodium hydrosulfide, sodium thiosulfate, carbon disulfide, sodium sulfite, sodium bisulfite, sodium sulfide, sodium disulfide, and thiourea dioxide. In summary, the slurry-bed hydrocracking catalyst prepared by this method involves complex processes and a long flow, with large quantities of various reagents used, resulting in a lack of significant advantages in environmental benefits, economic benefits, and technological advancement. Based on this, the inventors proposed this invention.

[0052] Reference Figure 1 As shown in the embodiments of the present invention, the preparation method of the molybdenum-based slurry-bed hydrocracking catalyst for inferior oil and the application method of the molybdenum-based slurry-bed hydrocracking catalyst for inferior oil in the inferior oil processing process are as follows:

[0053] (1) The tailings from the fractionation system of the slurry bed hydrocracking process of inferior oil are removed by the naphtha produced by the unit to obtain solid residue;

[0054] (2) Solid residue is calcined with oxygen to obtain solid powder;

[0055] (3) Dissolve the metallic molybdenum in the solid powder using ammonia water to obtain a solution;

[0056] (4) Add a methanol solution of zinc nitrate and dimethylimidazole to the solution and react to prepare the catalyst precursor C1;

[0057] (5) C1 was calcined under anaerobic conditions to prepare slurry bed hydrocracking catalyst C2.

[0058] Information on the sources of raw materials or equipment in the embodiments of the present invention is shown in Table 1.

[0059] Table 1 Raw Material and Equipment Information

[0060]

[0061] The evaluation and analysis methods for the prepared catalysts in this embodiment of the invention are as follows:

[0062] The test raw materials and the prepared slurry bed catalyst were analyzed and tested according to the national standards and conventional test methods in this technical field, and the catalyst cracking performance was evaluated using a slurry bed pilot plant (in this embodiment of the invention, the tailings produced by a 100-ton-level slurry bed pilot plant were used as the raw material for the preparation of molybdenum-based inferior oil slurry bed hydrocracking catalyst). Specific implementation examples:

[0064] Naphtha and slurry bed hydrocracking tailings were mixed at different mass ratios and then separated to remove oil at 80°C to obtain solid residue. In this embodiment of the invention, the separation and removal of solid residue can be carried out by hydrocyclone separator, centrifuge, plate and frame filter press, etc. The oil temperature during the separation operation is 70-100°C. The results of the oil removal test are shown in Table 2.

[0065] Table 2 Results of oil removal tests on slurry-bed hydrocracking tailings

[0066]

[0067] Note: Separation time refers to the total working time for removing oil from hydrocracking tailings using naphtha.

[0068] The solid residue was calcined in air in two stages: (1) calcined at 400℃ for 0.5 hours and 600℃ for 0.5 hours to obtain solid powder G1-1; (2) calcined at 400℃ for 1 hour and 600℃ for 1 hour to obtain solid powder G1-2; (3) calcined at 450℃ for 2 hours and 650℃ for 2 hours to obtain solid powder G1-3; (4) calcined at 550℃ for 2 hours and 700℃ for 2 hours to obtain solid powder G1-4; (5) calcined at 550℃ for 3 hours and 800℃ for 3 hours to obtain solid powder G1-5. The composition of solid powder G1 is shown in Table 3.

[0069] Table 3. Analysis of solid content in products obtained by roasting solids in slurry-bed hydrocracking tailings in air atmosphere.

[0070]

[0071] Example 1

[0072] 100g of solid powder G1 from slurry-bed hydrocracking tailings was weighed. Under stirring, the calcined solid powder was dissolved in ammonia water at a ratio of ammonia water / solid powder = 2 / 1 (mL / g) at 50℃ for 1 hour, yielding a solution Y1 and ammonia-insoluble matter, which were separated by filtration. A methanol solution of zinc nitrate and dimethylimidazole was added to solution Y1, with a molar ratio of zinc nitrate to molybdenum of 4 / 1 and a molar ratio of dimethylimidazole to zinc nitrate of 3 / 1. The reaction was stirred at room temperature for 4 hours. The resulting turbid liquid was filtered using a Buchner funnel, washed with distilled water, and dried at 60℃ for 1 hour. Then, it was calcined in an oxygen-free atmosphere at 400℃ for 1 hour to obtain carbon-supported catalyst C2-1 with molybdenum dispersed in a single atom. The recovery rate of metallic molybdenum was 80.1%.

[0073] Example 2

[0074] 100g of solid powder G1 from slurry-bed hydrocracking tailings was weighed. Under stirring, the calcined solid powder was dissolved in ammonia water (ammonia / solid powder = 2 / 1, mL / g), at 50℃ for 1 hour, yielding solution Y1 and ammonia-insoluble matter, which were separated by filtration. A methanol solution of zinc nitrate and dimethylimidazole was added to solution Y1, with a molar ratio of zinc nitrate to molybdenum of 4 / 1 and a molar ratio of dimethylimidazole to zinc nitrate of 3 / 1. The reaction was stirred at room temperature for 4 hours. The resulting turbid liquid was filtered using a Buchner funnel, washed with distilled water, and dried at 60℃ for 1 hour. Then, it was calcined in an oxygen-free atmosphere at 450℃ for 1.5 hours to obtain carbon-supported catalyst C2-2 with molybdenum dispersed in a single atom. The recovery rate of metallic molybdenum was 80.6%.

[0075] Example 3

[0076] 100g of solid powder G1 from slurry-bed hydrocracking tailings was weighed. Under stirring, the calcined solid powder was dissolved in ammonia water at a ratio of ammonia water / solid powder of 3 / 1 (mL / g) at 70℃ for 2 hours, yielding a solution Y1 and ammonia-insoluble matter, which were separated by filtration. A methanol solution of zinc nitrate and dimethylimidazole was added to solution Y1, with a molar ratio of zinc nitrate to molybdenum of 5 / 1 and a molar ratio of dimethylimidazole to zinc nitrate of 4 / 1. The reaction was stirred at room temperature for 4.5 hours. The resulting turbid liquid was filtered using a Buchner funnel, washed with distilled water, and dried at 95℃ for 4 hours. Then, it was calcined in an oxygen-free atmosphere at 600℃ for 2 hours to obtain carbon-supported catalyst C2-3 with molybdenum dispersed in a single atom. The recovery rate of metallic molybdenum was 85.5%.

[0077] Example 4

[0078] 100g of solid powder G1 from slurry-bed hydrocracking tailings was weighed. Under stirring, the calcined solid powder was dissolved in ammonia water at a ratio of ammonia water / solid powder of 3 / 1 (mL / g) at 70℃ for 2 hours, yielding a solution Y1 and ammonia-insoluble matter, which were separated by filtration. A methanol solution of zinc nitrate and dimethylimidazole was added to solution Y1, with a molar ratio of zinc nitrate to molybdenum of 5 / 1 and a molar ratio of dimethylimidazole to zinc nitrate of 4 / 1. The reaction was stirred at room temperature for 4.5 hours. The resulting turbid liquid was filtered using a Buchner funnel, washed with distilled water, and dried at 95℃ for 4 hours. Then, it was calcined in an oxygen-free atmosphere at 650℃ for 2.5 hours to obtain carbon-supported catalyst C2-4 with molybdenum dispersed in a single atom. The recovery rate of metallic molybdenum was 86.4%.

[0079] Example 5

[0080] 100g of solid powder G1 from slurry-bed hydrocracking tailings was weighed. Under stirring, the calcined solid powder was dissolved in ammonia water at a ratio of ammonia water / solid powder = 4 / 1 (mL / g) at 80℃ for 2 hours, yielding solution Y1 and ammonia-insoluble matter, which were separated by filtration. A methanol solution of zinc nitrate and dimethylimidazole was added to solution Y1, with a molar ratio of zinc nitrate to molybdenum of 8 / 1 and a molar ratio of dimethylimidazole to zinc nitrate of 4 / 1. The reaction was stirred at room temperature for 6 hours. The resulting turbid liquid was filtered using a Buchner funnel, washed with distilled water, and dried at 100℃ for 4.5 hours. Then, it was calcined in an oxygen-free atmosphere at 750℃ for 3 hours to obtain carbon-supported catalyst C2-5 with molybdenum dispersed in a single atom. The recovery rate of metallic molybdenum was 95.5%.

[0081] Example 6

[0082] 100g of solid powder G1 from slurry-bed hydrocracking tailings was weighed. Under stirring, the calcined solid powder was dissolved in ammonia water (ammonia / solid powder = 4 / 1, mL / g), at 80℃ for 3 hours, yielding solution Y1 and ammonia-insoluble matter, which were separated by filtration. A methanol solution of zinc nitrate and dimethylimidazole was added to solution Y1, with a molar ratio of zinc nitrate to molybdenum of 10 / 1 and a molar ratio of dimethylimidazole to zinc nitrate of 5 / 1. The reaction was stirred at room temperature for 8 hours. The resulting turbid liquid was filtered using a Buchner funnel, washed with distilled water, and dried at 120℃ for 6 hours. Then, it was calcined in an oxygen-free atmosphere at 800℃ for 4 hours to obtain carbon-supported catalyst C2-6 with molybdenum dispersed in a single atom. The recovery rate of metallic molybdenum was 97.4%.

[0083] Example 7

[0084] 100g of solid powder G1 from slurry-bed hydrocracking tailings was weighed. Under stirring, the calcined solid powder was dissolved in ammonia water at a ratio of ammonia water / solid powder = 5 / 1 (mL / g) at 90℃ for 4 hours, yielding a solution Y1 and ammonia-insoluble matter, which were separated by filtration. A methanol solution of zinc nitrate and dimethylimidazole was added to solution Y1, with a molar ratio of zinc nitrate to molybdenum of 12 / 1 and a molar ratio of dimethylimidazole to zinc nitrate of 5 / 1. The reaction was stirred at room temperature for 12 hours. The resulting turbid liquid was filtered using a Buchner funnel, washed with distilled water, and dried at 120℃ for 12 hours. Then, it was calcined in an oxygen-free atmosphere at 800℃ for 3 hours to obtain carbon-supported catalyst C2-7 with molybdenum in a single-atom dispersion. The recovery rate of metallic molybdenum was 98.9%.

[0085] Example 8

[0086] 100g of solid powder G1 from slurry-bed hydrocracking tailings was weighed. Under stirring, the calcined solid powder was dissolved in ammonia water at a ratio of ammonia water / solid powder = 6 / 1 (mL / g) at 100℃ for 6 hours, yielding a solution Y1 and ammonia-insoluble matter, which were separated by filtration. A methanol solution of zinc nitrate and dimethylimidazole was added to solution Y1, with a molar ratio of zinc nitrate to molybdenum of 16 / 1 and a molar ratio of dimethylimidazole to zinc nitrate of 6 / 1. The reaction was stirred at room temperature for 12 hours. The resulting turbid liquid was filtered using a Buchner funnel, washed with distilled water, and dried at 150℃ for 12 hours. Then, it was calcined in an oxygen-free atmosphere at 800℃ for 6 hours to obtain carbon-supported catalyst C2-8 with molybdenum dispersed in a single atom. The recovery rate of metallic molybdenum was 99.1%.

[0087] Comparative Example 1

[0088] Weigh 50g of molybdenum trioxide and dissolve it in ammonia water under stirring, with an ammonia / molybdenum trioxide ratio of 4 / 1 (mL / g). The dissolution temperature is 80℃, and the dissolution time is 2 hours, yielding solution Y1. Add a methanol solution of zinc nitrate and dimethylimidazole to solution S1, with a molar ratio of zinc nitrate to molybdenum of 8 / 1 and a molar ratio of dimethylimidazole to zinc nitrate of 4 / 1. Stir the reaction at room temperature for 12 hours. Filter the resulting turbid liquid using a Buchner funnel, wash with distilled water, and dry at 100℃ for 6 hours. Then calcine in an oxygen-free atmosphere at 800℃ for 3 hours to obtain carbon-supported catalyst CD-1 with molybdenum as the active component in a single-atom dispersion.

[0089] Comparative Example 2

[0090] 100g of solid powder G1 from slurry-bed hydrocracking tailings was weighed. Under stirring, the calcined solid powder was dissolved in ammonia water at a ratio of ammonia water / solid powder of 1 / 1 (mL / g), at 40℃ for 0.5 hours, yielding solution Y1 and ammonia-insoluble matter, which were separated by filtration. A methanol solution of zinc nitrate and dimethylimidazole was added to solution Y1, with a molar ratio of zinc nitrate to molybdenum of 2 / 1 and a molar ratio of dimethylimidazole to zinc nitrate of 2 / 1. The reaction was stirred at room temperature for 2 hours. The resulting turbid liquid was filtered using a Buchner funnel, washed with distilled water, and dried at 40℃ for 0.5 hours. Then, it was calcined in an oxygen-free atmosphere at 350℃ for 1 hour to obtain carbon-supported catalyst CD-2 with molybdenum in a single-atom dispersion. The recovery rate of metallic molybdenum was 69.2%.

[0091] Comparative Example 3

[0092] 100g of solid powder G1 from slurry-bed hydrocracking tailings was weighed. Under stirring, the calcined solid powder was dissolved in ammonia water at a ratio of ammonia water / solid powder of 10 / 1 (mL / g) at 120℃ for 10 hours, yielding a solution Y1 and ammonia-insoluble matter, which were separated by filtration. A methanol solution of zinc nitrate and dimethylimidazole was added to solution Y1, with a molar ratio of zinc nitrate to molybdenum of 20 / 1 and a molar ratio of dimethylimidazole to zinc nitrate of 10 / 1. The reaction was stirred at room temperature for 20 hours. The resulting turbid liquid was filtered using a Buchner funnel, washed with distilled water, and dried at 180℃ for 20 hours. Then, it was calcined in an oxygen-free atmosphere at 850℃ for 8 hours to obtain CD-3, a carbon-supported catalyst with molybdenum in a single-atom dispersion. The recovery rate of metallic molybdenum was 99.2%.

[0093] The molybdenum-based catalysts (C2-1, C2-2, C2-3, C2-4, C2-5, C2-6, C2-7, C2-8, CD-1, CD-2, CD-3) from Examples 1-8 and Comparative Examples 1-3 were used as feedstock, and mixed vacuum residue was used as feedstock. A small-scale slurry bed test apparatus was used at a reaction temperature of 420°C, a reaction pressure of 16 MPa, a catalyst dosage of 500 μg / g (based on metallic molybdenum), and a space velocity of 0.5 h⁻¹. -1 Hydrocracking tests were conducted under a hydrogen-to-oil volume ratio of 500. The evaluation results of hydrocracking of vacuum residue with different catalysts are shown in Table 5.

[0094] Table 4 Properties of Mixed Vacuum Residue

[0095]

[0096]

[0097] Note: The mixed vacuum residue was prepared by mixing Venezuelan vacuum residue, Karamay vacuum residue and West Pacific vacuum residue in a mass ratio of 3:1:1.

[0098] Table 5 Evaluation results of vacuum residue hydrocracking

[0099]

[0100]

[0101] As shown in Examples 1-8, the catalyst prepared by the method provided by this invention can achieve efficient recovery of deactivated molybdenum-based catalysts from slurry-bed hydrocracking tailings, with a molybdenum recovery rate exceeding 80%. With optimization of process parameters, the molybdenum recovery rate exceeds 95.5%. Data in Table 5 shows that the molybdenum-based catalyst prepared from slurry-bed hydrocracking tailings provided by this invention exhibits good hydrogenation performance and coking suppression ability, comparable to the molybdenum-based catalyst prepared from pure molybdenum trioxide (Comparative Example 1). The catalyst prepared from process tailings in this invention can save significant resource costs, representing a significant improvement. Under the same reaction conditions, the single-pass conversion rate of vacuum residue is >63 wt%, and the coking rate is <0.5 wt%. The above data indicate that the molybdenum-based catalyst recovery method involved in this invention has advantages such as simple process, mild conditions, high molybdenum recovery rate, and ease of low-cost industrial application. However, as process parameters continue to increase, such as increasing the volume of ammonia water, enhancing dissolution conditions, increasing the amount of zinc nitrate and dimethylimidazole, enhancing drying conditions, and enhancing anaerobic roasting conditions, the increase in molybdenum recovery rate is no longer significant, but the economic cost increases relatively significantly. At the same time, the inventors found that after enhancing anaerobic roasting conditions, the molybdenum crystal nuclei are damaged, resulting in physical recrystallization, which makes it impossible to achieve the requirements of fine particle size and high dispersion.

[0102] In summary, the molybdenum-based catalyst prepared in the embodiments of this invention exhibits excellent hydrogenation performance, making it particularly suitable for low-cost slurry-bed hydrocracking processes involving high-metal, high-carbon, and high-sulfur inferior oils. Furthermore, compared to the oil-soluble catalyst prepared in the "Recycling Method of Oil-Soluble Molybdenum-Based Slurry-Bed Hydrocracking Catalysts," the highly dispersed catalyst prepared from tailings in the embodiments of this invention can be effectively dispersed in heavy feedstocks, demonstrating not only excellent hydrocracking activity and inhibition of condensation and coking performance, but also significant resource savings, making it suitable for large-scale application.

[0103] Meanwhile, the inventors analyzed the technical solution disclosed in the prior art patent document CN108441884A, entitled "Molybdenum disulfide / carbon composite hydrogen evolution electrocatalyst and its preparation method". The technical solution disclosed in the patent is as follows: (1) Preparation of carbon: Using deionized water as solvent, a mixed solution of zinc salt and dimethylimidazole is prepared. The solid substance separated after stirring and reaction is the metal-organic framework material ZIF-8. After the metal-organic framework material ZIF-8 is calcined at high temperature, it is then cleaned. After washing and drying, carbon material is obtained; (2) Hydrothermal preparation of molybdenum disulfide / carbon composite material: using deionized water as solvent, a mixed solution of sodium molybdate tetrahydrate and thiourea is prepared, with the mass ratio of sodium molybdate tetrahydrate to thiourea being 1:1.5 to 1:3; the above mixed solution and the carbon material prepared in step (1) are placed together in a reaction vessel for hydrothermal reaction, the resulting product is filtered, washed with deionized water, and dried to obtain molybdenum disulfide / carbon composite material; wherein, the mass ratio of sodium molybdate tetrahydrate to carbon material is 15:1 to 2:1.

[0104] The inventor carefully read the patent with publication number CN108441884A and believes that it belongs to the field of electrocatalytic hydrogen evolution technology. The preparation method is based on a mixed solution of zinc salt and dimethylimidazole to prepare a metal-organic framework material ZIF-8, which is a carbon-coated zinc salt catalyst (carbon material). Then, molybdenum disulfide is loaded on it as a carrier, and finally molybdenum disulfide / carbon composite material is generated.

[0105] After comparison, the inventors believe that the embodiments of the present invention and the patent CN108441884A have at least the following differences: (1) The catalyst precursor of ZIF-8 coated molybdenum salt in the embodiments of the present invention is prepared based on metallic molybdenum extracted from waste. Molybdenum itself is a precious metal, so its preparation cost is different, and the final catalyst composition is also completely different; (2) The catalyst precursor of ZIF-8 coated molybdenum salt prepared in the embodiments of the present invention is then subjected to oxygen-free calcination to obtain a highly dispersed catalyst, while the patent CN108441884A does not have this step; (3) In the process of preparing the catalyst precursor of ZIF-8 coated molybdenum salt in the embodiments of the present invention, zinc in zinc nitrate is used as an auxiliary agent, and its main purpose is to provide high dispersion of molybdenum element. The competition coefficient additive is an additive added to improve the loading rate of the main active metal in the supported catalyst, so that the molybdenum atoms are more uniformly dispersed on the support. The molybdenum atoms are the main body for constructing the ZIF-8 structure. In contrast, the catalyst with carbon-coated zinc salt in the CN108441884A patent has zinc atoms as the main active metal, which is the main body for constructing the ZIF-8 structure. The ZIF-8 structures of the two are fundamentally different. (4) The final product prepared in the embodiment of the present invention is carbon-supported molybdenum (ZIF-8 structure), while the molybdenum disulfide supported by the ZIF-8 structure (carbon-coated zinc salt) in the CN108441884A patent is molybdenum disulfide supported by the ZIF-8 structure (carbon-coated zinc salt). The structure, use and function of the above molybdenum-based catalyst and the molybdenum disulfide / carbon composite material are completely different. In summary, the inventive concept of the molybdenum-based catalyst preparation scheme in the CN108441884A patent and the embodiment of the present invention are completely different.

[0106] For those skilled in the art, the specific embodiments described are merely illustrative of the present invention. Clearly, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solutions, or the direct application of the inventive concept and technical solutions to other situations without modification, are all within the protection scope of the present invention. That is, those skilled in the art can make various modifications and variations to the present invention without departing from its spirit and scope. Therefore, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention also intends to include these modifications and variations.

Claims

1. A method for preparing a molybdenum-based slurry-bed hydrocracking catalyst for inferior oil, characterized in that, include: After mixing the tailings of slurry bed hydrocracking with naphtha produced by slurry bed hydrocracking, the oil in the tailings is separated to obtain solid residue. The solid residue was calcined in air to obtain a solid powder; The calcined solid powder was dissolved in 2-6 ml of ammonia water per gram of solid powder under stirring conditions, and the dissolution temperature was controlled at 50-100℃ for 1-6 hours to obtain the first mixture. The first mixture is filtered to obtain a solution; A methanol solution of zinc nitrate and dimethylimidazole was added to the solution under stirring conditions. The mixture was reacted at room temperature for 4–12 h to obtain a second mixture; The second mixture is filtered to obtain the precipitate in the second mixture; The precipitate was dried at 60-150°C for 1-12 hours to prepare a ZIF-8-coated molybdenum salt catalyst precursor. The ZIF-8-coated molybdenum salt catalyst precursor was calcined in an oxygen-free atmosphere at a calcination temperature of 400-800°C for 1-6 hours to obtain a molybdenum-based low-quality oil slurry bed hydrocracking catalyst.

2. The method according to claim 1, characterized in that, The molar ratio of zinc nitrate to molybdenum in the solution is 4-16:1, and the molar ratio of dimethylimidazole to zinc nitrate is 3-6:

1.

3. The method according to claim 1, characterized in that, include: The calcined solid powder was dissolved in 4-6 ml of ammonia water per gram of solid powder under stirring conditions, and the dissolution temperature was controlled at 70-90℃ for 2-4 hours to obtain the first mixture. The first mixture is filtered to obtain a solution; A methanol solution of zinc nitrate and dimethylimidazole was added to the solution under stirring conditions. The mixture was reacted at room temperature for 4–6 hours to obtain a second mixture. The second mixture is filtered to obtain the precipitate in the second mixture; The precipitate was dried at 95-120°C for 4-6 hours to prepare the ZIF-8 coated molybdenum salt catalyst precursor. The ZIF-8-coated molybdenum salt catalyst precursor was calcined in an oxygen-free atmosphere at a calcination temperature of 450-650°C for 3-6 hours to obtain a molybdenum-based low-quality oil slurry bed hydrocracking catalyst.

4. The method according to claim 3, characterized in that, The molar ratio of zinc nitrate to molybdenum in the solution is 5-10:1, and the molar ratio of dimethylimidazole to zinc nitrate is 4-6:

1.

5. The method according to any one of claims 1 to 4, characterized in that, The mass ratio of naphtha to slurry bed hydrocracking tailings is 1~6:

1.

6. The method according to claim 5, characterized in that, The mass ratio of naphtha to slurry bed hydrocracking tailings is 1~2:

1.

7. The method according to claim 5, characterized in that, The temperature at which the oil is separated from the tailings is 70~100℃.

8. The method according to claim 7, characterized in that, The temperature at which the oil is separated from the tailings is 70~90℃.

9. The method according to claim 5, characterized in that, The solid residue is calcined in air at a temperature of 400-800°C for 1-6 hours to obtain solid powder.

10. The method according to claim 9, characterized in that, The solid residue is calcined in air at a temperature of 450-650°C for 2-4 hours to obtain solid powder.

11. A molybdenum-based slurry-bed hydrocracking catalyst for inferior oil, characterized in that, The molybdenum-based inferior oil slurry bed hydrocracking catalyst is prepared by the method described in any one of claims 1 to 10.

12. A method for applying a molybdenum-based slurry-bed hydrocracking catalyst for inferior oil in the processing of inferior oil, characterized in that, The molybdenum-based low-quality oil slurry bed hydrocracking catalyst and the diesel fraction produced by slurry bed hydrocracking are uniformly mixed at a volume ratio of 0.05~0.2:1 and then added to the low-quality oil feedstock. The molybdenum-based inferior oil slurry bed hydrocracking catalyst is prepared by the method described in any one of claims 1 to 10 for preparing the molybdenum-based inferior oil slurry bed hydrocracking catalyst.

13. The application method according to claim 12, characterized in that, The molybdenum-based slurry-bed hydrocracking catalyst for inferior oil is used at a dosage of 200-1000 μg / g (calculated as metallic molybdenum). The process conditions are: reaction pressure 10-20 MPa, reaction temperature 360-450 °C, and volume hourly space velocity 0.2-1.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 300-1000.

14. The application method according to claim 12, characterized in that, The molybdenum-based low-quality oil slurry bed hydrocracking catalyst and diesel fraction are uniformly mixed at a volume ratio of 0.05~0.1:1 and then added to the low-quality oil feedstock.

15. The application method according to claim 14, characterized in that, The molybdenum-based slurry-bed hydrocracking catalyst for inferior oil is used at a dosage of 300-600 μg / g (calculated as metallic molybdenum). The process conditions are: reaction pressure 10-16 MPa, reaction temperature 390-420℃, and volume hourly space velocity 0.2-0.5 h⁻¹. -1 The hydrogen-to-oil volume ratio is 300-500.

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