Preparation method of tungsten-based catalyst and application thereof

Abstract

The application belongs to the technical field of catalyst preparation, and particularly relates to a preparation method of a tungsten-based catalyst and application thereof. A tungsten source, a long-chain fatty acid amide, an organic solvent and a sulfiding agent are subjected to one-pot reaction to obtain a tungsten-based precursor mixed solution; and the tungsten-based precursor mixed solution is subjected to liquid separation to obtain an oil-soluble tungsten-based catalyst. The preparation method of the tungsten-based catalyst is simple and reliable, has low requirements on temperature and equipment, and is easy to operate. When the catalyst is used, no additional sulfiding agent needs to be added, the catalyst can be self-sulfided into an active component in situ in a slurry bed reactor, the active metal is highly dispersed in raw oil, the catalyst has good hydrogenation performance and coking inhibition performance, is suitable for slurry bed hydro-upgrading of crude oil of various qualities, can provide high-quality raw materials for a process of directly preparing chemicals from crude oil, and has a very wide application prospect.

Description

Technical Field

[0001] This invention relates to the field of catalyst preparation technology, and specifically to a method for preparing a tungsten-based catalyst and its application. Background Technology

[0002] Traditional crude oil processing mainly produces refined petroleum products, which account for about 60% of the total crude oil processing volume on average. Currently, my country's refining industry faces overcapacity. In the future, influenced by the development of new energy vehicles powered by hydrogen and electricity, the growth rate of demand for liquid fuels in the transportation sector will gradually decrease, while there is a significant shortage of organic chemical raw materials such as aromatics and olefins. Therefore, the transformation of refining enterprises from "fuel-oriented" to "chemical-oriented" is an inevitable development trend. The traditional refining process that maximizes the production of chemical raw materials mainly involves separating crude oil into light and heavy fractions through atmospheric and vacuum distillation. Light fractions are directly processed through steam cracking, reforming, and aromatization units to produce olefins and aromatics, while heavy fractions are processed through fixed-bed hydrocracking and slurry-bed (suspension-bed) hydrocracking units to further enhance the production of olefins and aromatics. This process is characterized by a long overall flow, high energy consumption, and large overall investment, which is not conducive to the structural transformation of traditional existing refineries. Since 2014, major international refining companies have begun developing technologies for directly producing chemical products such as olefins and aromatics from crude oil. Currently, two typical technologies have been established: steam cracking and catalytic cracking. However, due to the high susceptibility of catalysts, the demanding operation of cracking furnaces, and poor adaptability to feedstocks, direct one-step production of chemicals is not feasible for crude oils with high metal content, high density, wide distillation range, and high heavy component content. Therefore, slurry-bed hydrotreating of crude oil to reduce metal, sulfur, and nitrogen content, asphaltene content, and increase the proportion of light oil can provide an effective feedstock for one-step crude oil-to-chemicals production, which is of great significance.

[0003] Slurry-bed hydrocracking involves dispersing a small amount of catalyst in the feedstock as a solid powder or liquid. The feedstock and hydrogen are heated to the reaction temperature and then flow upwards through the reactor as a three-phase slurry (gas, liquid, solid). This process offers advantages such as strong feedstock adaptability, simple process, and high conversion rate. Currently, many international companies are researching heavy oil slurry-bed hydrocracking technology, including the EST process from ENI (Italy), the HDHPLUS-SHP process developed by Intevep (Venezuela) and Axens (France), the VRSH process from Chevron, the VCC process developed by KBR and BP, the Uniflex process from UOP, and the (HCAT / HC3) process from Headwater.

[0004] The key to the development of slurry-bed hydrocracking technology lies in the continuous improvement of high-quality hydrocracking catalysts. Among them, oil-soluble catalysts can be effectively dissolved in heavy feedstocks, exhibiting excellent hydrocracking effects while effectively suppressing coking, making them ideal catalysts. Chinese Patent CN201610804914.2 discloses the preparation of an active metal precursor by precipitating a soluble salt of Mo or W at 40-100℃, which is then reacted with C6-C20 organic acids to obtain an oil-soluble catalyst. Chinese Patent CN201410216485.8 discloses the preparation of an oil-soluble catalyst by reacting a reduced metal with an organic amine. Chinese Patent CN202010553349.3 describes the preparation of a suspended-bed hydrocracking catalyst by uniformly mixing a metal salt with a surfactant and thoroughly grinding the mixture. Chinese patent CN201510848631.3 discloses the preparation of oil-soluble catalysts by reacting metal salts with carboxylic acid organic compounds, alcohols, and sulfiding agents. US patent 4125455 discloses the hydrogenation application of metal salts composed of Group VIB metals (molybdenum, tungsten, and chromium) of C7-C32 fatty acids as catalysts, showing good hydrogenation performance at 430°C and 13.7 MPa with the addition of 590 ppm molybdenum octanoate as a catalyst. However, the aforementioned oil-soluble catalysts exist in the form of oxides, organometallic acid salts, or organometallic amine salts, requiring in-situ pre-sulfidation to convert inactive oxides into sulfides before use. Complete sulfidation of the active component is very difficult, which to some extent reduces catalyst performance. Furthermore, the obtained sulfide particles are difficult to disperse as oil-soluble metal precursors. Therefore, developing an oil-soluble tungsten-based catalyst containing sulfur ligands, which self-sulfidates into the active component in a slurry bed, is crucial for cost reduction and efficiency improvement in slurry bed crude oil hydrogenation processes. Summary of the Invention

[0005] In view of this, the present invention proposes a method for preparing a tungsten-based catalyst and its application. Before crude oil undergoes atmospheric and vacuum distillation or before entering a crude oil-to-chemicals unit, a slurry-bed hydrogenation pretreatment is performed under the action of an oil-soluble tungsten-based catalyst to improve the yield of light oil and provide high-quality feedstock for subsequent atmospheric and vacuum distillation processes or direct crude oil-to-chemicals production.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a tungsten-based catalyst, comprising the following steps:

[0007] S1. Take a tungsten source, long-chain fatty acid amide, organic solvent and sulfiding agent and react them in one pot to obtain a mixed solution of tungsten-based precursor;

[0008] S2. The oil-soluble tungsten-based catalyst is prepared by separating the mixed solution of tungsten-based precursors.

[0009] Preferably, in step S1, the tungsten source, long-chain fatty acid amide, organic solvent, and sulfiding agent are added together to the reactor and stirred and heated at 85℃~150℃ for 6~12h; in step S2, the solution obtained in S1 is cooled and allowed to stand to separate into layers, the aqueous phase is removed, and an oil-soluble tungsten-based catalyst dispersed in organic solvent is obtained.

[0010] Preferably, the tungsten source in step S1 is any one or a combination of tungsten trioxide, ammonium metatungstate, and ammonium paratungstate.

[0011] Preferably, the long-chain fatty acid amide in step S1 is any one or more of palmitic acid diethanolamide, lauric acid diethanolamide, stearic acid diethanolamide, oleic acid diethanolamide, betaine diethanolamide, arachidic acid diethanolamide, nonanoic acid diethanolamide, decanoic acid diethanolamide, myristic acid diethanolamide, ceramide, ceramide, beeswax diethanolamide, lacquer wax diethanolamide, decaenoic acid diethanolamide, eicostrienoic acid diethanolamide, and erucic acid diethanolamide.

[0012] Preferably, the organic solvent in step S1 is any one or more of toluene, petroleum ether, xylene, DMF, and n-butanol.

[0013] Preferably, the sulfiding agent in step S1 is one or more of ammonium sulfide, sodium sulfide, sodium hydrosulfide, sodium polysulfide, and thioacetamide.

[0014] Preferably, the molar ratio of tungsten source, long-chain fatty acid amide, organic solvent, and vulcanizing agent is 1:0.6 to 1:5 to 10:4 to 10.

[0015] The present invention also proposes an application of a tungsten-based catalyst, which is prepared by the preparation method mentioned above. The oil-soluble tungsten-based catalyst solution is mixed with crude oil in a static mixer and then introduced from the bottom of a slurry bed reactor along with hydrogen to carry out the crude oil hydrotreating reaction.

[0016] More preferably, the catalyst dosage is 50–1200 ppm, the reaction temperature is 330–460 °C, the reaction pressure is 5–20 MPa, and the liquid hourly space velocity is 0.2–1.5 h⁻¹. -1 The volume ratio of hydrogen to raw materials is 300 to 1500.

[0017] Optionally, the crude oil is one or more of paraffin-based crude oil, intermediate-based crude oil, and naphthenic crude oil.

[0018] Compared with existing technologies, this invention provides a method for preparing a tungsten-based catalyst and its application, which has the following beneficial effects:

[0019] This invention employs a one-pot reaction of a tungsten source, long-chain fatty acid amide, organic solvent, and sulfiding agent to obtain a mixed solution of tungsten-based precursors. The resulting oil-soluble tungsten-based catalyst is then directly prepared by liquid-liquid separation. This preparation method is simple and reliable, with low requirements for temperature and equipment, and is easy to operate. When using the catalyst, no additional sulfiding agent is needed; the catalyst can self-sulfidize in situ into the active component in a slurry bed reactor. The active metal exhibits ultra-high dispersion in the feedstock oil, demonstrating excellent hydrogenation and coking performance. It is suitable for slurry bed hydrotreating of crude oils of various qualities and can provide high-quality feedstock for crude oil-to-chemicals processes, showing a very broad application prospect. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Unless otherwise specified, the experimental methods used in the embodiments of this application are all conventional methods.

[0022] Unless otherwise specified, all experimental materials used in the examples were purchased from conventional reagent stores.

[0023] Example 1

[0024] Weigh 30g of tungsten trioxide and add it to 100ml of water. Weigh 30g of oleic acid diethanolamide, 120g of toluene, and 70g of thioacetamide, and add them sequentially to the above solution. Heat the mixture to 145℃ and stir for 3 hours. Centrifuge the resulting solution, separate the oil phase, and obtain an oil-soluble tungsten-based catalyst dispersed in an organic solvent, named W-1.

[0025] Example 2

[0026] Weigh 30g of ammonium metatungstate and add 80ml of water. Weigh 30g of palmitic acid diethanolamide, 150g of toluene, and 80g of sodium sulfide, and add them sequentially to the above solution. Heat to 130℃ and stir for 4 hours. Centrifuge the resulting solution, separate the oil phase, and obtain an oil-soluble tungsten-based catalyst dispersed in an organic solvent, named W-2.

[0027] Example 3

[0028] Weigh 30g of tungsten trioxide and add it to 100ml of water. Weigh 30g of lauric acid diethanolamide, 150g of toluene, and 70g of sodium hydrosulfide, and add them sequentially to the above solution. Heat the mixture to 150℃ and stir for 3 hours. Centrifuge the resulting solution, separate the liquid phase, and obtain an oil-soluble tungsten-based catalyst dispersed in an organic solvent, named W-3.

[0029] Example 4

[0030] Weigh 30g of ammonium metatungstate and add 100ml of water. Weigh 30g of stearic acid diethanolamide, 160g of petroleum ether, and 70g of thioacetamide, and add them sequentially to the above solution. Heat to 150℃ and stir for 3 hours. Centrifuge the resulting solution, separate the oil phase, and obtain an oil-soluble tungsten-based catalyst dispersed in an organic solvent, named W-4.

[0031] Comparative Example 1

[0032] Comparative Example 1 is a commercially available molybdenum octanoate catalyst.

[0033] Comparative Example 2

[0034] Comparative Example 2 is a commercially available nickel naphthenate catalyst.

[0035] The oil-soluble tungsten-based catalyst of this invention can be used in slurry-bed hydrocracking processes for various crude oils. The method of application involves directly adding the oil-soluble tungsten-based catalyst to the crude oil. During the heating process, it undergoes self-sulfidation to generate active metallic tungsten sulfide, exhibiting excellent hydrogenation activity. The catalyst dosage is 50–1200 ppm (based on metallic W), the reaction temperature is 330–460°C, the reaction pressure is 5–20 MPa, and the liquid hourly space velocity is 0.2–1.5 h⁻¹. -1 The volume ratio of hydrogen to raw materials is 300 to 1500.

[0036] Table 1 Properties of Saudi Crude Oil

[0037] <![CDATA[Density (20°C) / g·cm -3 > 0.8896 Viscosity (20℃) / mPa·s 22.667 S content / wt% 3.57 N content / wt% 0.19 ＜180℃ 11.51 180-350℃ 32.95 350-520℃ 32.61 ＞520℃ 22.93 ＜520℃ 77.07 Asphalt / wt% 3.16 Hydrogen to carbon ratio (H / C) 1.74

[0038] The oil-soluble tungsten-based catalysts (W-1, W-2, W-3, W-4), molybdenum octanoate catalyst, and nickel naphthenate catalyst from Examples 1, 2, 3, and 4 were used as feedstock from Saudi crude oil (properties shown in Table 1). The reaction was carried out at a reaction temperature of 390°C, a hydrogen pressure of 7 MPa, a catalyst addition of 200 μg / g (based on metallic tungsten), and a liquid hourly space velocity of 1 h⁻¹. -1 The volume ratio of hydrogen to feedstock was 1200. Table 2 shows the evaluation results of Saudi crude oil hydrotreating with different oil-soluble tungsten-based catalysts under the same reaction conditions.

[0039] Table 2 Evaluation Results of Saudi Crude Oil Hydrogenation Upgrading Experiment

[0040]

[0041]

[0042] As shown in Table 2, the oil-soluble tungsten-based catalyst prepared in this invention exhibits excellent hydrogenation performance at a reaction temperature of 390℃, an initial hydrogen pressure of 7 MPa, a catalyst dosage of 200 μg / g (based on metal), and a liquid hourly space velocity of 1 h⁻¹. -1 Under the condition of a hydrogen-to-feed volume ratio of 1200, the asphaltene content in the oil can be effectively reduced, the light oil yield can be increased by 6 percentage points, and the coke production can be <0.1 wt%. Compared with commercial molybdenum isooctanoate catalysts, the oil-soluble tungsten-based catalyst provided by this invention can significantly reduce coke formation and has a better effect on reducing the asphaltene content in Saudi crude oil, while commercial nickel naphthenate exhibits poor activity in crude oil hydrorefining processes. After hydrorefining and upgrading with the oil-soluble tungsten-based catalyst of this invention, crude oil can be directly used in downstream crude oil direct chemical production processes, reducing the stringent requirements of crude oil steam cracking and catalytic cracking on the oil quality.

[0043] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. However, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions claimed by the present invention.

Claims

1. A method for preparing a tungsten-based catalyst, characterized in that, Includes the following steps: S1. Take a tungsten source, long-chain fatty acid amide, organic solvent and sulfiding agent and react them in one pot to obtain a mixed solution of tungsten-based precursor; S2. The oil-soluble tungsten-based catalyst is prepared by separating the tungsten-based precursor mixture solution; In step S1, the tungsten source, long-chain fatty acid amide, organic solvent, and sulfiding agent are added to the reactor and stirred and heated at 85℃~150℃ for 6~12h; in step S2, the solution obtained in S1 is cooled and allowed to stand to separate into layers, the aqueous phase is removed, and an oil-soluble tungsten-based catalyst dispersed in organic solvent is obtained. The tungsten source in step S1 is any one or a combination of tungsten trioxide, ammonium metatungstate, and ammonium paratungstate. In step S1, the long-chain fatty acid amide is any one or more of the following: palmitic acid diethanolamide, lauric acid diethanolamide, stearic acid diethanolamide, oleic acid diethanolamide, behenic acid diethanolamide, arachidic acid diethanolamide, nonanoic acid diethanolamide, decanoic acid diethanolamide, myristic acid diethanolamide, ceramide, ceramide, beeswax acid diethanolamide, lacquer wax diethanolamide, decaenoic acid diethanolamide, eicostrienoic acid diethanolamide, and erucic acid diethanolamide. The sulfiding agent in step S1 is one or more of ammonium sulfide, sodium sulfide, sodium hydrosulfide, and thioacetamide; The molar ratio of tungsten source, long-chain fatty acid amide, organic solvent, and vulcanizing agent is 1:0.6~1:5~10:4~10.

2. The method for preparing a tungsten-based catalyst according to claim 1, characterized in that, In step S1, the organic solvent is either toluene or xylene, or either of both.

3. An application of a tungsten-based catalyst, prepared using the method described in claim 1 or 2, characterized in that, The oil-soluble tungsten-based catalyst solution is mixed with crude oil in a static mixer and then introduced from the bottom of the slurry bed reactor along with hydrogen to carry out the crude oil hydrotreating reaction.

4. The application of the tungsten-based catalyst according to claim 3, characterized in that, The catalyst dosage is 50~1200ppm, the reaction temperature is 330~460℃, the reaction pressure is 5~20MPa, and the liquid hourly space velocity is 0.2~1.5h. -1 The volume ratio of hydrogen to raw materials is 300~1500.

5. The application of a tungsten-based catalyst according to claim 3 or 4, characterized in that, The crude oil is one or more of the following: paraffinic crude oil, intermediate-based crude oil, and naphthenic crude oil.

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