Catalyst, preparation method thereof, method for reducing viscosity of thickened oil and application of catalyst
By preparing catalysts containing zirconium and tungsten sources, the problem of the difficulty in separating and recycling existing catalysts has been solved, enabling heavy oil extraction with excellent viscosity reduction effect and low cost.
Patent Information
- Application Number
- CN202411088457.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-09
- Publication Date
- 2026-02-10
AI Technical Summary
Existing catalyst preparation processes are complex, difficult to mass-produce, difficult to separate after viscosity reduction, and cannot be recycled, resulting in high costs.
A catalyst was prepared by mixing a solution containing zirconium and tungsten sources with an alkaline solution, followed by hydrothermal reaction, solid-liquid separation, and calcination. This catalyst is used to reduce the viscosity of heavy oil and can be reused at high temperatures.
The preparation process is simple, the catalyst is easy to separate and recycle, it significantly reduces the viscosity of heavy oil, has excellent viscosity reduction effect, and reduces production costs.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention relates to the field of oil extraction, specifically to a catalyst, its preparation method, a method for reducing the viscosity of heavy oil, and their applications. Background Technology
[0002] Heavy oil extraction methods mainly include physical methods (such as steam flooding and steam huff and puff) and chemical methods (such as reservoir combustion and active water viscosity reduction). Thermal recovery is the primary method for heavy oil extraction, but it has high investment costs. Recently, chemical modification for viscosity reduction, which utilizes steam injection to increase the required reaction temperature, has made some progress, but it is ineffective at low formation temperatures. Hydrothermal catalytic viscosity reduction technology is a cutting-edge heavy oil extraction technology. It involves injecting high-temperature steam and a catalyst into the reservoir, utilizing the heat provided by the steam to catalyze the heavy oil under hydrothermal conditions, partially altering its quality and irreversibly reducing its viscosity, thus facilitating extraction. However, existing catalysts suffer from problems such as complex preparation processes, difficulty in separating the catalyst after viscosity reduction, affecting oil quality, and high costs due to the inability to reuse the catalyst.
[0003] Therefore, it is necessary to develop hydrothermal viscosity-reducing catalysts for heavy oil that are simple to prepare, easy to separate after application, recyclable, and have excellent viscosity-reducing effects. Summary of the Invention
[0004] The purpose of this invention is to overcome the above-mentioned problems existing in the prior art, and to provide a catalyst, its preparation method, a method for reducing the viscosity of heavy oil, and its application. The catalyst has excellent viscosity-reducing effect on heavy oil, and its preparation process is simple. It is easy to separate after application and can be recycled.
[0005] To achieve the above objectives, the present invention provides a method for preparing a catalyst, the method comprising:
[0006] (1) Provide a solution containing zirconium source and tungsten source, and mix the solution with an alkaline solution under stirring until the pH of the resulting suspension is 8.5-11;
[0007] (2) The suspension obtained in step (1) is subjected to a hydrothermal reaction at 100-200℃;
[0008] (3) The product obtained in step (2) is subjected to solid-liquid separation and drying, and then calcined at a temperature not lower than 460°C.
[0009] A second aspect of the present invention provides a catalyst prepared by the method described above.
[0010] A third aspect of the present invention provides the use of the catalyst as described in the second aspect in reducing the viscosity of heavy oil.
[0011] A fourth aspect of the present invention provides a method for reducing the viscosity of heavy oil, the method comprising: subjecting the heavy oil to a viscosity-reducing reaction in the presence of a catalyst;
[0012] The catalyst is as described in the second aspect.
[0013] The technical solution of the present invention has the following advantages:
[0014] 1. In view of the fact that traditional catalysts are complex and difficult to mass-produce, a hydrothermal viscosity-reducing catalyst for heavy oil with a simple preparation process and excellent viscosity-reducing effect has been found.
[0015] 2. The hydrothermal viscosity-reducing catalyst for heavy oil provided by this invention can break the bonds of CS, CN, CO and CC on the long chain of heavy oil, reduce the content of gum and asphaltenes, increase the content of saturated hydrocarbons and aromatic hydrocarbons, and convert heavy components into light components, resulting in a significant viscosity-reducing effect. Detailed Implementation
[0016] The endpoints and any values of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of the various ranges, the endpoint values of the various ranges and individual point values, and individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.
[0017] In a first aspect, the present invention provides a method for preparing a catalyst, the method comprising:
[0018] (1) Provide a solution containing zirconium source and tungsten source, and mix the solution with an alkaline solution under stirring until the pH of the resulting suspension is 8.5-11;
[0019] (2) The suspension obtained in step (1) is subjected to a hydrothermal reaction at 100-200℃;
[0020] (3) The product obtained in step (2) is subjected to solid-liquid separation and drying, and then calcined at a temperature not lower than 460°C.
[0021] The method described above is simple and can produce solid heteropolyacid catalysts in a one-pot process. The resulting catalyst exhibits good viscosity reduction in heavy oil, can be recycled, and reduces production costs.
[0022] Preferably, the zirconium source is selected from zirconium oxychloride and / or zirconium nitrate.
[0023] Preferably, the tungsten source is ammonium metatungstate.
[0024] Preferably, in step (1), the molar ratio of tungsten to zirconium in the solution containing the zirconium source and the tungsten source is (0.028-0.532):1, more preferably (0.062-0.177):1, and even more preferably (0.117-0.149):1. This further ensures the viscosity-reducing effect of the obtained catalyst.
[0025] Preferably, in the solution containing zirconium source and tungsten source, the concentration of zirconium is 0.2-0.5 mol / L.
[0026] Preferably, the solution containing zirconium and tungsten sources is prepared by dissolving the zirconium and tungsten sources in a solvent, preferably water. Taking zirconium oxychloride and ammonium metatungstate as examples, their corresponding powder products are taken and dissolved in water to obtain a solution containing both zirconium and tungsten sources.
[0027] Preferably, in step (1), the stirring speed is 200-500 rpm. This ensures that the zirconium source is fully converted into zirconium hydroxide.
[0028] According to the present invention, preferably, in step (1), the mixing method is as follows: an alkaline solution is added dropwise to a solution containing a zirconium source and a tungsten source. During the dropwise addition, a white precipitate is gradually formed. The dropwise addition rate can be 1-3 mL / min relative to 50 mL of the solution containing the zirconium source and the tungsten source.
[0029] Preferably, the amount of alkaline solution used is such that the pH of the suspension is 9-10. This also ensures that a large amount of precipitate exists in the suspension. It is understood that during the mixing process, the pH of the suspension may temporarily reach the above range, but then decrease and deviate from this range as the reaction progresses. Therefore, the phrase "so that the pH of the suspension is 9-10" means that the pH of the suspension is basically stable within this range. For example, if it can be stable for 30 seconds, then generally no significant changes will occur.
[0030] Preferably, the alkaline solution is ammonia water, and more preferably ammonia water with a mass concentration of 22-30 wt% (for example, it can be 22, 23, 24, 25, 26, 27, 28, 29, 30 and any two of the above values and any value within the range).
[0031] Preferably, in step (2), the temperature of the hydrothermal reaction is 110-180℃, more preferably 130-150℃ (for example, it can be 130, 132, 135, 138, 140, 142, 145, 148, 150 and any value within the range formed by any two of the above values), and more preferably 145-150℃.
[0032] The specific method of solid-liquid separation is not particularly limited, as long as it can achieve the purpose of separating the solid and liquid phases. For example, it can be at least one of centrifugation and filtration. The product obtained in step (2) can be cooled to room temperature first, and then the solid and liquid phases can be separated and dried.
[0033] Preferably, the hydrothermal reaction time is 8-20 hours, more preferably 10-14 hours. The hydrothermal reaction can be carried out in a hydrothermal reactor.
[0034] Under the above conditions, it is possible to further ensure that tungsten is uniformly loaded on zirconium hydroxide.
[0035] After the hydrothermal reaction, the material can be cooled to room temperature before drying.
[0036] The present invention does not impose any particular restrictions on the drying method and temperature. For example, the drying temperature can be 90-120℃ and the time can be 8-20h.
[0037] Preferably, in step (3), the calcination temperature is 500-800℃, more preferably 600-700℃ (for example, it can be 610, 620, 630, 640, 650, 660, 670, 680, 690, 700 and any value within the range formed by any two of the above values), and more preferably 670-700℃.
[0038] Preferably, the roasting time is 2-6 hours, more preferably 3-4 hours.
[0039] Secondly, the present invention provides a catalyst prepared by the method described above.
[0040] Preferably, the catalyst contains zirconium oxide and tungsten oxide, wherein the tungsten oxide content is 3-50 wt% relative to the total weight of the catalyst, preferably 4.5-25 wt% (e.g., it can be 4.5, 4.9, 5, 8, 10, 12, 15, 18, 20, 22, 25, or any value within the range formed by any two of the above values).
[0041] Preferably, the catalyst has a specific surface area of 45-200 m². 2 / g, preferably 50-120m 2 / g, pore volume is 0.10-0.40cm³ 3 / g, preferably 0.15-0.30cm 3 / g, with an average pore size of 60-120nm, preferably 70-100nm.
[0042] The catalyst provided by this invention has a simple preparation process and is easy to separate after use, overcoming the problems of complex processes and difficulty in mass production of traditional catalysts. Furthermore, the catalyst has strong acidity and good stability.
[0043] The third aspect of the present invention provides the application of the catalyst as described in the second aspect in the viscosity reduction of heavy oil.
[0044] A fourth aspect of the present invention provides a method for reducing the viscosity of heavy oil, the method comprising: subjecting the heavy oil to a viscosity-reducing reaction in the presence of a catalyst;
[0045] The catalyst is as described in the second aspect.
[0046] Preferably, the method includes: mixing heavy oil, catalyst and water to carry out a viscosity-reducing reaction.
[0047] Preferably, the temperature of the viscosity reduction reaction is 200-300℃, and more preferably 220-260℃ (for example, it can be 220, 230, 240, 250, 260 and any value within the range formed by any two of the above values).
[0048] Preferably, the viscosity reduction reaction time is 6-48 hours, more preferably 18-24 hours (for example, it can be 18, 19, 20, 21, 22, 23, 24, or any value within the range formed by any two of the above values).
[0049] Under the above conditions, a better viscosity reduction effect can be further guaranteed.
[0050] According to the present invention, preferably, the mass ratio of heavy oil, catalyst, and water is 100:(0.25-3):(40-500), more preferably 100:(0.5-1):(60-200). This further ensures a better viscosity reduction rate.
[0051] It is understandable that heavy oil is crude oil with a high content of asphaltenes and gums and a high viscosity. It is also generally called heavy oil. The content of gums and asphaltenes in heavy oil is generally greater than 30 wt%, while the content of alkanes and aromatics is generally less than 50 wt%.
[0052] According to a preferred embodiment of the present invention, the viscosity of the heavy oil at 50°C is 40,000-100,000 mPa·s (for example, it can be 40,000, 45,000, 50,000, 55,000, 60,000, 65,000, 70,000, 75,000, 80,000, 85,000, 90,000, 95,000, 100,000, and any value within the range formed by any two of the above values).
[0053] The viscosity was determined using ASTM D2196-2015 (Test Method A, test temperature 50℃, viscometer: Shanghai Lichen NDJ-8S).
[0054] After the viscosity-reducing reaction, the catalyst can be separated by solid-liquid separation (such as centrifugation). The catalyst provided by this invention is easy to separate and convenient for recycling.
[0055] The present invention will be described in detail below through embodiments.
[0056] In the following examples, the zirconium oxychloride used has a molecular weight of 178.13 g / mol, ammonium metatungstate is its hydrate with a molecular weight of 2956.3 g / mol, and zirconium nitrate is its hydrate with a molecular weight of 423.56 g / mol.
[0057] In the following examples and comparative examples, "to reach a certain pH value" means that the pH is stable (at least stable for 30 seconds) at that value.
[0058] In the following examples and comparative examples, unless otherwise specified, the dropping rate of the alkaline solution is 2 mL / min relative to 50 mL of solution containing zirconium and tungsten sources.
[0059] Example 1
[0060] 4.03 g of zirconium oxychloride powder and 0.18 g of ammonium metatungstate powder were dissolved in water to obtain a solution with a zirconium concentration of 0.3 mol / L. Ammonia solution with a mass concentration of 25 wt% was added dropwise to the solution while stirring at 400 rpm, resulting in a precipitate. The addition was stopped when the pH reached 9.2. The mixture was transferred to a hydrothermal autoclave and kept at 150 °C for 12 h. After cooling to room temperature, solid-liquid separation was performed. The solid phase was removed and dried in an oven (110 °C, 12 h). After drying, it was calcined at 700 °C for 3 h to obtain the target product, a hydrothermal viscosity-reducing catalyst for heavy oil.
[0061] Example 2
[0062] 4.03 g of zirconium oxychloride powder and 0.41 g of ammonium metatungstate powder were dissolved in water to achieve a zirconium concentration of 0.3 mol / L. Ammonia solution with a mass concentration of 25 wt% was added dropwise to the solution while stirring at 400 rpm, resulting in a precipitate. The addition was stopped when the pH reached 9.5. The mixture was transferred to a hydrothermal autoclave and kept at 150 °C for 12 h. After cooling to room temperature, solid-liquid separation was performed. The solid phase was removed and dried in an oven (110 °C, 12 h). After drying, it was calcined at 700 °C for 3 h to obtain the target product, a hydrothermal viscosity-reducing catalyst for heavy oil.
[0063] Example 3
[0064] 5.37 g of zirconium nitrate powder and 0.41 g of ammonium metatungstate powder were dissolved in water to achieve a zirconium concentration of 0.3 mol / L. Ammonia solution with a mass concentration of 25 wt% was added dropwise to the solution at 400 rpm, resulting in a precipitate. The addition was stopped when the pH reached 9.2. The mixture was transferred to a hydrothermal autoclave and kept at 150 °C for 12 h. After cooling to room temperature, solid-liquid separation was performed. The solid phase was dried in an oven (110 °C, 12 h), and then calcined at 700 °C for 3 h to obtain the target product, a hydrothermal viscosity-reducing catalyst for heavy oil.
[0065] Example 4
[0066] 4.03 g of zirconium oxychloride powder and 0.41 g of ammonium metatungstate powder were dissolved in water to achieve a zirconium concentration of 0.3 mol / L. Ammonia solution with a mass concentration of 28 wt% was added dropwise to the solution at 300 rpm, resulting in a precipitate until the pH reached 9.7. The mixture was transferred to a hydrothermal autoclave and kept at 150 °C for 12 h. After cooling to room temperature, solid-liquid separation was performed. The solid phase was dried in an oven (110 °C, 12 h), and then calcined at 700 °C for 3 h to obtain the target product, a hydrothermal viscosity-reducing catalyst for heavy oil.
[0067] Example 5
[0068] 4.03 g of zirconium oxychloride powder and 0.41 g of ammonium metatungstate powder were dissolved in water to achieve a zirconium concentration of 0.5 mol / L. Ammonia solution with a mass concentration of 25 wt% was added dropwise to the solution at 400 rpm, resulting in a precipitate until the pH reached 9.4. The mixture was transferred to a hydrothermal autoclave and kept at 130 °C for 12 h. After cooling to room temperature, solid-liquid separation was performed. The solid phase was dried in an oven (100 °C, 10 h), and then calcined at 700 °C for 3 h to obtain the target product, a hydrothermal viscosity-reducing catalyst for heavy oil.
[0069] Example 6
[0070] 4.03 g of zirconium oxychloride powder and 0.41 g of ammonium metatungstate powder were dissolved in water to achieve a zirconium concentration of 0.5 mol / L. Ammonia solution with a mass concentration of 25 wt% was added dropwise to the solution at 400 rpm, resulting in a precipitate until the pH reached 9.8. The mixture was transferred to a hydrothermal autoclave and kept at 150 °C for 12 h. After cooling to room temperature, solid-liquid separation was performed. The solid phase was dried in an oven (110 °C, 12 h), and then calcined at 600 °C for 4 h to obtain the target product, a hydrothermal viscosity-reducing catalyst for heavy oil.
[0071] Comparative Example 1
[0072] 4.03 g of zirconium oxychloride (without a tungsten source) was dissolved in water to achieve a zirconium concentration of 0.3 mol / L. Ammonia solution with a mass concentration of 25 wt% was added dropwise to the solution while stirring at 400 rpm, resulting in a precipitate. The addition was stopped when the pH reached 9.2. The mixture was transferred to a hydrothermal autoclave and kept at 150 °C for 12 h. After cooling to room temperature, solid-liquid separation was performed. The solid phase was dried in an oven (110 °C, 12 h), and then calcined at 700 °C for 3 h to obtain the target product, a hydrothermal viscosity-reducing catalyst for heavy oil.
[0073] Comparative Example 2
[0074] 4.03 g of zirconium oxychloride powder and 0.41 g of ammonium metatungstate powder were dissolved in water to achieve a zirconium concentration of 0.3 mol / L. While stirring at 400 rpm, 25 wt% ammonia solution was added dropwise until the pH reached 7.6. The mixture was transferred to a hydrothermal autoclave and kept at 150 °C for 12 h. After cooling to room temperature, solid-liquid separation was performed. The solid phase was dried in an oven (110 °C, 12 h), and then calcined at 700 °C for 3 h to obtain the target product, a hydrothermal viscosity reducer for heavy oil.
[0075] Comparative Example 3
[0076] 4.03 g of zirconium oxychloride powder and 0.41 g of ammonium metatungstate powder were dissolved in water to achieve a zirconium concentration of 0.3 mol / L. While stirring at 400 rpm, 25 wt% ammonia solution was added dropwise until the pH reached 9.5. The mixture was transferred to a hydrothermal autoclave and kept at 80 °C for 12 h. After cooling to room temperature, solid-liquid separation was performed. The solid phase was dried in an oven (110 °C, 12 h), and then calcined at 700 °C for 3 h to obtain the target product, a hydrothermal viscosity reducer for heavy oil.
[0077] Comparative Example 4
[0078] 4.03 g of zirconium oxychloride powder and 0.41 g of ammonium metatungstate powder were dissolved in water to achieve a zirconium concentration of 0.3 mol / L. Ammonia solution with a mass concentration of 25 wt% was added dropwise to the solution while stirring at 400 rpm until the pH reached 9.5. The mixture was transferred to a hydrothermal autoclave and kept at 120 °C for 12 h. After cooling to room temperature, solid-liquid separation was performed. The solid phase was dried in an oven (110 °C, 12 h) and then calcined at 400 °C for 3 h to obtain the target product, a hydrothermal viscosity-reducing catalyst for heavy oil.
[0079] Comparative Example 5
[0080] 0.41 g of ammonium metatungstate (zirconium-free) powder was dissolved in water to achieve a tungsten concentration of 0.3 mol / L. Ammonia solution with a mass concentration of 25 wt% was added dropwise to the solution while stirring at 400 rpm until the pH reached 7.6. The mixture was transferred to a hydrothermal autoclave and kept at 150 °C for 12 h. After cooling to room temperature, solid-liquid separation was performed. The solid phase was dried in an oven (110 °C, 12 h) and then calcined at 700 °C for 3 h to obtain the target product, a hydrothermal viscosity reducer for heavy oil.
[0081] Comparative Example 6
[0082] 4.03 g of zirconium oxychloride (without tungsten source) powder was dissolved in water to achieve a zirconium concentration of 0.3 mol / L. While stirring at 400 rpm, 25 wt% ammonia solution was added dropwise until the pH reached 9.5, resulting in a precipitate. The precipitate was washed with deionized water until the pH reached 7. The filter cake was dried in an oven (110℃, 24 h) and then ground to obtain a white powder. 0.41 g of ammonium metatungstate (without zirconium source) powder was dissolved in water to prepare an ammonium metatungstate solution. The white powder was immersed in the ammonium metatungstate solution and refluxed at 100℃ for 18 h, then dried in an oven (110℃, 12 h). After drying, it was calcined at 700℃ for 3 h to obtain the target product: a hydrothermal viscosity reducer for heavy oil.
[0083] In the following test examples, the viscosity value at 50°C was determined according to ASTM D2196-2015 (Test Method A, test temperature 50°C, viscometer is Shanghai Lichen NDJ-8S).
[0084] Test Example 1
[0085] The catalysts prepared in the above examples and comparative examples, as well as natural heavy oil (from an oil field in Northwest China) with a viscosity of 47266 mPa·s at 50°C, were tested as follows.
[0086] 50g of heavy oil, 0.25g of catalyst, and 50ml of deionized water were added to a reaction vessel and reacted at 240℃ for 18h. After cooling to room temperature, the mixture was removed and its viscosity at 50℃ was measured. The viscosity reduction rate (%) was taken as the ratio of the viscosity difference before and after viscosity reduction to the initial viscosity. The results are as follows:
[0087] Table 1
[0088]
[0089]
[0090] Test Example 2
[0091] The catalysts prepared in the above examples and comparative examples, as well as natural heavy oil (from an oil field in Northwest China) with a viscosity of 47266 mPa·s at 50°C, were tested as follows.
[0092] 50g of heavy oil, 0.5g of catalyst, and 100ml of deionized water were added to a reaction vessel and reacted at 260℃ for 24h. After cooling to room temperature, the mixture was removed and its viscosity at 50℃ was measured. The viscosity reduction rate (%) was taken as the ratio of the viscosity difference before and after viscosity reduction to the initial viscosity. The results are as follows:
[0093] Table 2
[0094]
[0095]
[0096] Test Example 3
[0097] The catalysts prepared in the above examples and comparative examples, as well as natural heavy oil (from an oil field in Northeast China), with a viscosity of 83566 mPa·s at 50°C, were tested as follows.
[0098] 50g of heavy oil, 0.25g of catalyst, and 50ml of deionized water were added to a reaction vessel and reacted at 240℃ for 18h. After cooling to room temperature, the mixture was removed and its viscosity at 50℃ was measured. The viscosity reduction rate (%) was taken as the ratio of the viscosity difference before and after viscosity reduction to the initial viscosity. The results are as follows:
[0099] Table 3
[0100]
[0101]
[0102] Test Example 4
[0103] The catalysts prepared in the above examples and comparative examples, as well as natural heavy oil (from an oil field in Northeast China), with a viscosity of 83566 mPa·s at 50°C, were tested as follows.
[0104] 50g of heavy oil, 0.5g of catalyst, and 100ml of deionized water were added to a reaction vessel and reacted at 260℃ for 24h. After cooling to room temperature, the mixture was removed and its viscosity at 50℃ was measured. The viscosity reduction rate (%) was taken as the ratio of the viscosity difference before and after viscosity reduction to the initial viscosity. The results are as follows:
[0105] Table 4
[0106]
[0107]
[0108] The above results show that the heavy oil hydrothermal viscosity-reducing catalyst obtained by the method provided in this invention can achieve excellent viscosity-reducing effect when applied to heavy oil hydrothermal viscosity reduction.
[0109] Test Example 5
[0110] The products prepared in the above embodiments were characterized as follows:
[0111] The content of zirconium oxide and tungsten oxide in the catalyst relative to the total mass of the catalyst was determined by measuring the content of oxygen, tungsten and zirconium elements using energy dispersive spectroscopy (EDS characterization) and calculating the content of tungsten oxide and zirconium oxide.
[0112] Specific surface area, pore volume, and pore size were determined by physical adsorption (BET method).
[0113] The results are shown in Table 5.
[0114] Table 5
[0115]
[0116]
[0117] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.
Claims
1. A method for preparing a catalyst, characterized in that, The method includes: (1) Provide a solution containing zirconium source and tungsten source, and mix the solution with an alkaline solution under stirring until the pH of the resulting suspension is 8.5-11; (2) The suspension obtained in step (1) is subjected to a hydrothermal reaction at 100-200℃; (3) The product obtained in step (2) is subjected to solid-liquid separation and drying, and then calcined at a temperature not lower than 460°C.
2. The method according to claim 1, wherein, The zirconium source is selected from zirconium oxychloride and / or zirconium nitrate; And / or, the tungsten source is ammonium metatungstate.
3. The method according to claim 1, wherein, In step (1), the molar ratio of tungsten to zirconium in the solution containing zirconium source and tungsten source is (0.028-0.532):1, preferably (0.062-0.177):1, and more preferably (0.117-0.149):1; And / or, in solutions containing zirconium and tungsten sources, the concentration of zirconium is 0.2-0.5 mol / L.
4. The method according to any one of claims 1-3, wherein, The solution containing zirconium and tungsten sources is prepared by dissolving the zirconium and tungsten sources in a solvent, preferably water.
5. The method according to claim 1, wherein, In step (1), the stirring speed is 200-500 rpm; And / or, in step (1), the mixing method is: adding an alkaline solution dropwise to a solution containing a zirconium source and a tungsten source; And / or, the amount of alkaline solution used makes the pH of the suspension 9-10; And / or, the alkaline solution is ammonia water, preferably ammonia water with a mass concentration of 22-30 wt%.
6. The method according to any one of claims 1-3, wherein, In step (2), the temperature of the hydrothermal reaction is 110-180℃, preferably 130-150℃, and more preferably 145-150℃; Preferably, the hydrothermal reaction time is 8-20 hours, and more preferably 10-14 hours.
7. The method according to any one of claims 1-3, wherein, In step (3), the roasting temperature is 500-800℃, preferably 600-700℃, and more preferably 670-700℃; Preferably, the roasting time is 2-6 hours, and more preferably 3-4 hours.
8. The catalyst prepared by the method according to any one of claims 1-7.
9. The catalyst according to claim 8, wherein, The catalyst contains zirconium oxide and tungsten oxide, wherein the tungsten oxide content is 3-50 wt% relative to the total weight of the catalyst, preferably 4.5-25 wt%.
10. The catalyst according to claim 8 or 9, wherein, The catalyst has a specific surface area of 45-200 m². 2 / g, preferably 50-120m 2 / g, pore volume is 0.10-0.40cm³ 3 / g, preferably 0.15-0.30cm 3 / g, with an average pore size of 60-120nm, preferably 70-100nm.
11. The use of the catalyst according to any one of claims 8-10 in reducing the viscosity of heavy oil.
12. A method for reducing the viscosity of heavy oil, characterized in that, The method includes: subjecting heavy oil to a viscosity-reducing reaction in the presence of a catalyst; The catalyst is as described in any one of claims 8-10.
13. The method according to claim 12, wherein, The method includes: mixing heavy oil, catalyst and water to carry out a viscosity-reducing reaction; And / or, the temperature of the viscosity-reducing reaction is 200-300℃, preferably 220-260℃; And / or, the viscosity reduction reaction time is 6-48 hours, preferably 18-24 hours.
14. The method according to claim 12 or 13, wherein, The mass ratio of heavy oil, catalyst and water is 100:(0.25-3):(40-500), preferably 100:(0.5-1):(60-200); And / or, the viscosity of the heavy oil at 50°C is 40,000-100,000 mPa·s.