A method for removing sulfur-containing organic compounds in oil products by using a molybdenum phosphide composite catalyst

Abstract

The present invention discloses a method for removing sulfur-containing organic compounds from oil products using a molybdenum phosphide composite catalyst. The method comprises catalytically oxidizing the sulfur-containing organic compounds in the oil products using the molybdenum phosphide composite catalyst, wherein the molybdenum phosphide composite catalyst comprises nitrogen-phosphorus co-doped carbon nanosheets, on which molybdenum phosphide nanoparticles are loaded. The prepared molybdenum phosphide composite catalyst has the advantages of strong catalytic activity, high selectivity, and good stability. It can be widely used to remove sulfur-containing organic compounds from petroleum products, exhibits very excellent oxidative desulfurization activity, can achieve rapid and effective removal of sulfur-containing organic compounds from petroleum products, and can achieve highly selective ultra-deep oxidative desulfurization. It has the advantages of simple process, convenient operation, low cost, high removal efficiency, and good removal effect, and has good economic benefits and application prospects.

Description

Technical Field

[0001] The present invention belongs to the field of heterogeneous catalysis technology and petrochemical technology, and relates to a method for removing sulfur-containing organic compounds in oil products, and specifically to a method for removing sulfur-containing organic compounds in oil products by using a molybdenum phosphide composite catalyst. Background Art

[0002] In recent decades, the combustion of large quantities of sulfur-containing fossil fuels has led to a dramatic increase in sulfur dioxide emissions, inevitably causing a series of environmental problems and seriously affecting human health. In October 2017, the World Health Organization's International Agency for Research on Cancer classified sulfur dioxide as a Group 3 carcinogen. Thanks to the continuous regulation of fuel laws and regulations, the sulfur content in fuel used in transportation vehicles has dropped dramatically from 2000 ppm to 10 ppm over the past 20 years. This has intensified the demand for large-scale production of sulfur-free fuels. Therefore, there is an urgent need to develop a streamlined, efficient, and low-cost desulfurization technology.

[0003] Hydrodesulfurization (HDS) is the most commonly used method for removing sulfur-containing organic compounds from fuel oil. However, this method is not ideal for removing difficult-to-treat benzothiophenes, such as benzothiophene, dibenzothiophene, and 4,6-dimethyldibenzothiophene. Furthermore, the reaction requires high temperatures and pressures (300–400°C and 30–130 atm), which makes desulfurization expensive. Oxidative desulfurization (ODS) has attracted widespread attention as an alternative or complementary technology to HDS due to its mild reaction conditions (60–100°C) and high removal efficiency for refractory benzothiophenes. During ODS, sulfur-containing organic compounds are oxidized to their corresponding sulfoxides and sulfones in the presence of an oxidant and a catalyst. These oxidation products have higher polarity than other hydrocarbons and their parent sulfur compounds and can be removed from the fuel through various separation methods. However, the efficiency of ODS depends entirely on the activity of the catalyst. Therefore, the development of high-performance catalysts is a key scientific challenge for the implementation of this technology.

[0004] Among the many catalysts, molybdenum phosphide has the potential to play a huge catalytic role in the oxidative desulfurization process due to its unique electronic properties, multi-party composition and structure. First, molybdenum phosphide easily reacts with oxidants to form electrophilic reactive intermediates, which is considered to be the driving force for efficient ODS. In addition, molybdenum phosphide has abundant free electrons, which means that it is more likely to produce a large number of unsaturated metal sites, which is crucial for promoting the effective oxidation of aromatic organic sulfur compounds. Despite this, the preparation of molybdenum phosphide requires harsh conditions and uses flammable phosphorus and highly toxic phosphine as phosphating agents, which undoubtedly hinders large-scale synthesis and application. Therefore, obtaining a molybdenum phosphide composite catalyst with strong catalytic activity, high selectivity and good stability and a supporting process for its simple, easy-to-operate and low-cost preparation method are of great significance for achieving the effective conversion of sulfur-containing organic pollutants in petroleum products and improving the availability of petroleum products. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a method for removing sulfur-containing organic compounds in oil products using a molybdenum phosphide composite catalyst with low cost, high removal efficiency and good removal effect.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A method for removing sulfur-containing organic compounds in oil products using a molybdenum phosphide composite catalyst comprises catalytically oxidizing the sulfur-containing organic compounds in the oil products using the molybdenum phosphide composite catalyst; the molybdenum phosphide composite catalyst comprises nitrogen-phosphorus co-doped carbon nanosheets, on which molybdenum phosphide nanoparticles are loaded.

[0008] The above method is further improved, wherein the mass ratio of molybdenum phosphide particles to nitrogen-phosphorus co-doped carbon nanosheets in the molybdenum phosphide composite catalyst is 2 to 40; the mass fraction of nitrogen in the nitrogen-phosphorus co-doped carbon nanosheets is 2% to 8% of the nitrogen-phosphorus co-doped carbon nanosheets; and the mass fraction of phosphorus is 4% to 15% of the nitrogen-phosphorus co-doped carbon nanosheets.

[0009] The above method is further improved, and the preparation method of the molybdenum phosphide composite catalyst comprises the following steps:

[0010] S1, preparing a molybdenum-based metal-organic framework into a molybdenum-based metal-organic framework dispersion, adding a melamine dispersion, and stirring to prepare a molybdenum-based metal-organic framework / melamine dispersion;

[0011] S2, mixing the molybdenum-based metal organic framework / melamine dispersion obtained in step S1 with the phytic acid solution to perform a solvothermal reaction, centrifuging, and freeze-drying to obtain a molybdenum phosphide composite catalyst precursor powder;

[0012] S3. calcining the molybdenum phosphide composite catalyst precursor powder obtained in step S2 in an argon atmosphere to obtain a molybdenum phosphide composite catalyst.

[0013] The above method is further improved, in step S1, the preparation method of the molybdenum-based metal-organic framework comprises the following steps:

[0014] (1) adding molybdenum trioxide to ultrapure water and stirring to obtain a molybdenum trioxide dispersion; the mass ratio of the molybdenum trioxide to the ultrapure water is 1:70-100; and the stirring time is 0.5-2 hours;

[0015] (2) adding imidazole to the molybdenum trioxide dispersion obtained in step (1) to carry out a hydrothermal reaction, washing, and drying to obtain a molybdenum-based metal organic framework. The mass ratio of imidazole to molybdenum trioxide is 0.48 to 0.50:1; the hydrothermal reaction is carried out at a temperature of 100 to 140° C.; the hydrothermal reaction time is 12 to 24 hours; the washing is performed by washing the filtered product 3 to 6 times with ultrapure water; the drying process is carried out under vacuum conditions; and the drying temperature is 40 to 80° C.

[0016] The above method is further improved, in step S1, the concentration of the molybdenum-based metal organic framework dispersion is 25-200 g / L; the concentration of the melamine dispersion is 30-50 g / L; the stirring time is 0.5-2 h;

[0017] The above method is further improved, in step S2, the mass fraction of the phytic acid solution is 16% to 20%; the volume ratio of the phytic acid solution to the molybdenum-based metal organic framework / melamine dispersion is 0.5 to 0.8:1; the solvent thermal reaction temperature is 60 to 80°C; the solvent thermal reaction time is 12 to 24 hours; and the freeze drying time is 12 to 24 hours;

[0018] The above method is further improved in that in step S3, the calcination temperature is 800-900°C; and the calcination heating rate is 2-10°C / min.

[0019] The above method is further improved by using a molybdenum phosphide composite catalyst to catalytically oxidize the sulfur organic compounds in the oil product, comprising the following steps: mixing the molybdenum phosphide composite catalyst, acetonitrile and hydrogen peroxide with the sulfur organic compound oil product, physically mixing and heating to start the catalytic oxidation reaction, and extracting and separating to complete the removal of the sulfur organic compounds in the oil product.

[0020] The above method is further improved, wherein the amount of the molybdenum phosphide composite catalyst is 1 to 3 g per liter of sulfur-containing organic compound oil; the molar ratio of hydrogen peroxide to sulfur in the sulfur-containing organic compound oil is 6:1; the sulfur-containing organic compound in the sulfur-containing organic compound oil is at least one of dibenzothiophene and 4,6-dimethyldibenzothiophene; the concentration of the sulfur-containing organic compound in the sulfur-containing organic compound oil is 1000 to 2000 ppm; the catalytic oxidation reaction is carried out at a temperature of 50 to 70° C.; and the catalytic oxidation reaction time is 30 to 60 minutes.

[0021] The above method is further improved by using an oxidative desulfurization reaction device to desulfurize the high-sulfur fuel; the oxidative desulfurization reaction device includes a mixing tank, a reactor, an extractor, a separator, a buffer tank and a finished product tank. The desulfurization treatment of the high-sulfur fuel includes the following steps:

[0022] 1) adding the molybdenum phosphide composite catalyst, high sulfur fuel oil, extractant and oxidant into a mixing tank and mixing them evenly;

[0023] 2) pumping the uniformly mixed solution in step 1) into a reactor to carry out an oxidative desulfurization reaction;

[0024] 3) transporting the reaction product solution obtained by the oxidative desulfurization reaction in step 2) to an extractor for extraction treatment;

[0025] 4) transferring the mixed solution obtained after the extraction treatment in step 3) to a separator and allowing it to settle naturally for 10 to 30 minutes to obtain an upper oil phase and a lower mixed phase of extractant, unconsumed oxidant, and catalyst;

[0026] 5) The upper oil phase separated in step 4) is sequentially transported to a buffer tank and a finished product tank to obtain clean fuel oil, and the lower mixed phase is returned to the mixing tank and mixed again with the high-sulfur fuel oil to complete the continuous desulfurization treatment of the high-sulfur fuel oil;

[0027] The above method is further improved in that a three-leaf agitator is provided at the bottom of the mixing tank, a heat exchange device and several three-leaf agitators are provided in the reactor; a three-leaf agitator is provided inside the extractor; and the separator is in the shape of an inverted cone and is provided with discharge pipes at the upper and lower parts.

[0028] Compared with the prior art, the advantages of the present invention are:

[0029] (1) The present invention provides a method for removing sulfur-containing organic compounds in oil products using a molybdenum phosphide composite catalyst. The molybdenum phosphide composite catalyst used has the advantages of strong catalytic activity, high selectivity, good stability, etc., and can be widely used to remove sulfur-containing organic compounds (such as dibenzothiophene and 4,6-dimethyldibenzothiophene) in petroleum products, and can achieve rapid and effective removal of sulfur-containing organic compounds in petroleum products. Therefore, when the molybdenum phosphide composite catalyst is used to catalytically oxidize sulfur-containing organic compounds in oil products, it can quickly and efficiently achieve effective conversion of sulfur-containing organic compounds in fuel products, and can achieve ultra-high efficiency and ultra-deep oxidative desulfurization. It has the advantages of simple process, convenient operation, low cost, high removal efficiency, good removal effect, etc., and has excellent economic benefits and excellent application prospects. More importantly, the molybdenum phosphide composite catalyst used in the present invention can selectively remove organic sulfur compounds in oil products, and can quickly and completely remove organic sulfur compounds in oil products while ensuring the quality of oil products, showing very good adaptability, high use value and good application prospects.

[0030] (2) In the present invention, the mass ratio of nitrogen-phosphorus co-doped carbon nanosheets to molybdenum phosphide particles in the molybdenum phosphide composite catalyst is 2 to 40. By optimizing the mass ratio of nitrogen-phosphorus co-doped carbon nanosheets to molybdenum phosphide particles, the catalytic activity of the catalyst can be more effectively improved, thereby more efficiently removing organic sulfur compounds from oil products. At the same time, the mass fraction of nitrogen in the nitrogen-phosphorus co-doped carbon nanosheets is 2% to 8%, and the mass fraction of phosphorus is 4% to 15%. The rich nitrogen and phosphorus doping can effectively adjust the electronic structure of the carbon substrate, enhance the interaction between the carbon substrate and molybdenum phosphide, and thus improve the stability of the catalyst's activity, thereby also being able to remove organic sulfur compounds from oil products in a long-term and deep manner.

[0031] (3) The present invention uses a molybdenum-based metal organic framework as a molybdenum precursor, phytic acid as a phosphorus source, and melamine as a carbon source. The precursors are prone to strong coordination to form a cross-linked structure, and a nanostructured molybdenum phosphide anchored on nitrogen and phosphorus co-doped carbon nanosheets can be obtained by a simple one-step pyrolysis. Therefore, the method for preparing the molybdenum phosphide composite catalyst in the present invention has the advantages of simple process, operation method, low cost, green and pollution-free, and does not use flammable phosphorus and highly toxic phosphine as phosphating agents. The equipment requirements are not high, the repeatability is strong, and large-scale production can be achieved, which is conducive to industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0033] Figure 1This is a comparison chart of the removal effects of the molybdenum phosphide composite catalysts (MoP@NPC-0.10, MoP@NPC-0.15, MoP@NPC-0.20, MoP@NPC-0.25, and MoP@NPC-0.30) in Example 1 of the present invention on dibenzothiophene sulfur in fuel.

[0034] Figure 2 This is a diagram showing the corresponding sulfur conversion effect when the molybdenum phosphide composite catalyst (MoP@NPC-0.25) in Example 2 of the present invention removes dibenzothiophene and 4,6-dimethyldibenzothiophene from fuel.

[0035] Figure 3 This is a diagram showing the corresponding sulfur conversion effect when the molybdenum phosphide composite catalyst (MoP@NPC-0.25) in Example 3 of the present invention removes dibenzothiophene from fuel under different oxidant dosage conditions.

[0036] Figure 4 This is a diagram showing the corresponding sulfur conversion effect when the molybdenum phosphide composite catalyst (MoP@NPC-0.25) in Example 4 of the present invention removes dibenzothiophene from fuel under different extractant dosage conditions.

[0037] Figure 5 This is a diagram showing the selective removal efficiency of dibenzothiophene in fuel by the molybdenum phosphide composite catalyst (MoP@NPC-0.25) in Example 5 of the present invention in the presence of different representative interferents.

[0038] Figure 6 Process flow chart for removing sulfur-containing organic compounds from oil products using a molybdenum phosphide composite catalyst in Example 6 of the present invention. DETAILED DESCRIPTION

[0039] The present invention will be further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the scope of protection of the present invention is not limited thereby.

[0040] In the examples of the present invention, the raw materials and instruments used are all commercially available. Unless otherwise specified, the processes used are conventional processes, the equipment used is conventional equipment, and the data obtained are the average values of more than three repeated experiments.

[0041] Example 1

[0042] A method for removing sulfur-containing organic compounds from oil products using a molybdenum phosphide composite catalyst, specifically removing dibenzothiophene from oil products using a molybdenum phosphide composite catalyst, comprising the following steps:

[0043] The catalytic oxidative desulfurization activity of the molybdenum phosphide composite catalyst of the present invention was investigated. Specifically, the molybdenum phosphide composite catalyst prepared in Examples 1-5 was used to remove dibenzothiophene from oil products, comprising the following steps:

[0044] 10 mg of each molybdenum phosphide composite catalyst (MoP@NPC-0.10, MoP@NPC-0.15, MoP@NPC-0.20, MoP@NPC-0.25, and MoP@NPC-0.30) was accurately weighed and added to 10 mL of a 1000 ppm dibenzothiophene (DBT)-n-octane solution (simulated petroleum containing DBT). 2 mL of 99% acetonitrile was then added and stirred for 10 minutes to reach extraction equilibrium. Then, 36 μL of a 30% hydrogen peroxide solution (oxidant, O / S molar ratio of 6) was added. The catalytic oxidation reaction was carried out at 60°C with magnetic stirring at 600 rpm for 60 minutes. The catalytic oxidation reaction was carried out in acetonitrile, converting DBT into dibenzothiophene sulfone, which remained in the acetonitrile, thus removing DBT from the oil. After the reaction is completed, the acetonitrile phase (lower layer) and the oil phase (upper layer) are separated to obtain clean fuel oil.

[0045] In this embodiment, after the reaction is completed, the content of sulfur in dibenzothiophene in the product solution obtained by the reaction is measured by gas chromatography, and the conversion rate of sulfur in dibenzothiophene is obtained by calculation. The results are as follows: Figure 1 shown. Figure 1 This is a comparison chart of the removal effects of the molybdenum phosphide composite catalysts (MoP@NPC-0.10, MoP@NPC-0.15, MoP@NPC-0.20, MoP@NPC-0.25, MoP@NPC-0.30) on dibenzothiophene sulfur in fuel oil in Example 1 of the present invention. Figure 1 It can be seen that all molybdenum phosphide composite catalysts can effectively catalytically oxidize and remove dibenzothiophene from fuel. Among them, MoP@NPC-0.25 and MoP@NPC-0.30 can both achieve a 100% removal rate of sulfur from dibenzothiophene in oil within 60 minutes. These results show that the molybdenum phosphide composite catalysts prepared by the present invention have excellent catalytic oxidation performance. The total sulfur content in the oil treated with the molybdenum phosphide composite catalyst prepared by the present invention is less than 10ppm, meeting the Euro V fuel standard, and the total desulfurization rate is as high as 100%. In particular, the molybdenum phosphide composite catalyst (MoP@NPC-0.25) demonstrates excellent catalytic oxidation of dibenzothiophene under conditions of low metal loading, showing good economic benefits and industrial application prospects.

[0046] In this embodiment, the molybdenum phosphide composite catalyst (MoP@NPC-0.25) used includes nitrogen-phosphorus co-doped carbon nanosheets, on which nanoscale molybdenum phosphide particles are loaded. The mass ratio of the nanoscale molybdenum phosphide particles to the nitrogen-phosphorus co-doped carbon nanosheets is 26.62%. The nitrogen content of the nitrogen-phosphorus co-doped carbon nanosheets is 6.3%, and the phosphorus content is 12.9%.

[0047] In this embodiment, the preparation method of the molybdenum phosphide composite catalyst (MoP@NPC-0.25) used includes the following steps:

[0048] (1) Add 1.05 g of molybdenum trioxide to 80 mL of ultrapure water and stir for 20 min to obtain a molybdenum trioxide dispersion;

[0049] (2) adding 0.50 g of imidazole to the dispersion obtained in step (1), and then hydrothermally reacting at 120° C. for 12 h, centrifuging the solid product, and vacuum drying at 50° C. for 12 h to obtain a molybdenum-based metal-organic framework;

[0050] (3) Weighing 0.25 g of the platinum-based metal-organic framework obtained in step (2) and 1.00 g of melamine were added to 40 mL of ultrapure water and ultrasonically treated for 30 min to obtain a platinum-based metal-organic framework / melamine dispersion;

[0051] (4) adding 20 mL of a 15.3% phytic acid solution to the molybdenum-based metal organic framework / melamine dispersion obtained in step (3), stirring at 60° C. for 20 h to obtain a precursor solution;

[0052] (5) After the precursor solution obtained in step (4) is cooled to room temperature, it is centrifuged to obtain a solid product, which is freeze-dried for 12 hours and then calcined in an argon atmosphere at 800°C with a heating rate of 5°C / min for 3 hours to obtain a molybdenum phosphide composite catalyst, namely MoP@NPC-0.25.

[0053] In this embodiment, the molybdenum phosphide composite catalyst (MoP@NPC-0.10) used is basically the same as MoP@NPC-0.25, with the only difference being that in MoP@NPC-0.10, the mass ratio of nanoscale molybdenum phosphide particles to nitrogen and phosphorus co-doped carbon nanosheets is 4.21%.

[0054] In this embodiment, the molybdenum phosphide composite catalyst (MoP@NPC-0.15) used is basically the same as MoP@NPC-0.25, with the only difference being that in MoP@NPC-0.15, the mass ratio of nanoscale molybdenum phosphide particles to nitrogen and phosphorus co-doped carbon nanosheets is 8.84%.

[0055] In this embodiment, the molybdenum phosphide composite catalyst (MoP@NPC-0.20) used is basically the same as MoP@NPC-0.25, with the only difference being that in MoP@NPC-0.20, the mass ratio of nanoscale molybdenum phosphide particles to nitrogen and phosphorus co-doped carbon nanosheets is 18.93%.

[0056] In this embodiment, the molybdenum phosphide composite catalyst (MoP@NPC-0.30) used is basically the same as MoP@NPC-0.25, with the only difference being that in MoP@NPC-0.30, the mass ratio of nanoscale molybdenum phosphide particles to nitrogen and phosphorus co-doped carbon nanosheets is 36.64%.

[0057] Example 2

[0058] A method for removing sulfur-containing organic compounds from oil products using a molybdenum phosphide composite catalyst, specifically using a molybdenum phosphide composite catalyst (MoP@NPC-0.25) to remove dibenzothiophene and 4,6-dimethyldibenzothiophene from oil products, is basically the same as Example 1, except that the simulated petroleum in Example 2 is a dibenzothiophene-n-octane solution or a 4,6-dimethyldibenzothiophene-n-octane solution with a sulfur concentration of 1000 ppm.

[0059] In this embodiment, the reaction system was sampled at 5 min, 10 min, 20 min, 30 min, 45 min and 60 min of reaction, and the sulfur content of dibenzothiophene and 4,6-dimethyldibenzothiophene in the product solution obtained at the reaction time was measured. The conversion rate of sulfur in dibenzothiophene and 4,6-dimethyldibenzothiophene was obtained by calculation. The results are as follows: Figure 2 shown. Figure 2 This is the sulfur conversion effect diagram corresponding to the removal of dibenzothiophene and 4,6-dimethyldibenzothiophene in fuel by the molybdenum phosphide composite catalyst (MoP@NPC-0.25) in Example 2 of the present invention. Figure 2 It can be seen that the molybdenum phosphide composite catalyst (MoP@NPC-0.25) of the present invention can quickly and efficiently remove sulfur-containing organic compounds in fuel. After 60 minutes of reaction, the removal rates of dibenzothiophene and 4,6-dimethyldibenzothiophene reach 100% and 87.45%, respectively. The apparent reaction rate constants of the oxidative desulfurization of dibenzothiophene and 4,6-dimethyldibenzothiophene by the molybdenum phosphide composite catalyst (MoP@NPC-0.25) reach 0.0698 min -1 and 0.0303min -1 .

[0060] Example 3

[0061] A method for removing sulfur-containing organic compounds from oil products using a molybdenum phosphide composite catalyst, specifically using a molybdenum phosphide composite catalyst (MoP@NPC-0.25) to remove dibenzothiophene from oil products, is basically the same as Example 1, except that the oxidative desulfurization reaction in Example 3 uses different amounts of hydrogen peroxide, namely 12 μL, 24 μL, 36 μL, 48 μL, and 60 μL, respectively.

[0062] Figure 3 The figure shows the sulfur conversion effect of the molybdenum phosphide composite catalyst (MoP@NPC-0.25) in Example 3 of the present invention when removing dibenzothiophene from fuel under different oxidant dosage conditions. Figure 3 As the amount of hydrogen peroxide increases, the catalytic oxidation efficiency of dibenzothiophene in oil by the molybdenum phosphide composite catalyst (MoP@NPC-0.25) continues to improve. When the amount of hydrogen peroxide reaches 36 μL (O:S = 6), the molybdenum phosphide composite catalyst (MoP@NPC-0.25) can completely remove dibenzothiophene at a concentration of 1000 ppm in the simulated fuel within 60 minutes. These results demonstrate that the molybdenum phosphide composite catalyst (MoP@NPC-0.25) can achieve excellent desulfurization efficiency even in the presence of relatively low amounts of oxidant, demonstrating its high economic practicality.

[0063] Example 4

[0064] A method for removing sulfur-containing organic compounds from oil products using a molybdenum phosphide composite catalyst, specifically using a molybdenum phosphide composite catalyst (MoP@NPC-0.25) to remove dibenzothiophene from oil products, is basically the same as Example 1, except that the oxidative desulfurization reaction in Example 4 uses different amounts of acetonitrile, namely 1 mL, 2 mL, 5 mL, and 10 mL, respectively.

[0065] Figure 4 The figure shows the sulfur conversion effect of the molybdenum phosphide composite catalyst (MoP@NPC-0.25) in Example 4 of the present invention when removing dibenzothiophene from fuel under different extractant dosage conditions. Figure 4 Even with just 1 mL of acetonitrile, the molybdenum phosphide composite catalyst (MoP@NPC-0.25) completely removed dibenzothiophene at a concentration of 1000 ppm in the simulated fuel within 60 minutes. These results demonstrate that the molybdenum phosphide composite catalyst (MoP@NPC-0.25) can achieve excellent desulfurization efficiency even in the presence of minimal amounts of acetonitrile, demonstrating its high economic practicality.

[0066] Example 5

[0067] A method for removing sulfur-containing organic compounds from oil products using a molybdenum phosphide composite catalyst, specifically using a molybdenum phosphide composite catalyst (MoP@NPC-0.25) to remove dibenzothiophene from oil products, is basically the same as Example 1, except that: cyclohexane, 1-butene, toluene, and naphthalene are added to the simulated petroleum of dibenzothiophene in Example 5 at a mass fraction of 10%, respectively.

[0068] Figure 5 The figure shows the selective removal efficiency of dibenzothiophene in fuel by the molybdenum phosphide composite catalyst (MoP@NPC-0.25) in Example 5 of the present invention under the conditions of the presence of different representative interferences. Figure 5 When 10% cyclohexane, 1-butene, toluene, and naphthalene are present in the oil, the molybdenum phosphide composite catalyst (MoP@NPC-0.25) achieves removal rates of 98.34%, 100%, 94.88%, and 100%, respectively, for dibenzothiophene at a concentration of 1000 ppm. These results demonstrate that the molybdenum phosphide composite catalyst (MoP@NPC-0.25) is capable of selectively removing sulfur-containing organic compounds from oil.

[0069] Example 6

[0070] A method for removing sulfur-containing organic compounds from oil products using a molybdenum phosphide composite catalyst, specifically using a molybdenum phosphide composite catalyst to continuously desulfurize high-sulfur fuel oil, the process flow chart of which is as follows: Figure 6 As shown, the following steps are included:

[0071] 1) Add 2 g of molybdenum phosphide composite catalyst (MoP@NPC-0.25), 2 L of high-sulfur fuel oil, 200 mL of acetonitrile, and 7.2 mL of 30% hydrogen peroxide to a mixing tank (containing 2 L of 1000 ppm dibenzothiophene simulated fuel oil) and start the stirrer to mix thoroughly.

[0072] 2) pumping the uniformly mixed solution in step 1) into the reactor, turning on the agitator and the heat exchanger to carry out oxidative desulfurization reaction for 60 minutes;

[0073] 3) transferring the reaction product solution obtained by the oxidative desulfurization reaction in step 2) to an extractor, turning on the stirrer, and performing extraction treatment;

[0074] 4) transferring the mixed solution obtained after the extraction treatment in step 3) to a separator and allowing it to settle naturally for 10 to 30 minutes to obtain an upper oil phase and a lower mixed phase of extractant, unconsumed oxidant, and catalyst;

[0075] 5) The upper oil phase separated in step 4) is transported from the upper discharge pipe to the buffer tank and the finished product tank in sequence to obtain clean fuel oil, and the lower mixed phase is returned from the lower discharge pipe to the mixing tank to be mixed with the high-sulfur fuel oil again, completing the continuous desulfurization treatment of the high-sulfur fuel oil;

[0076] 6) Continue desulfurizing the sulfur-containing fuel by repeating steps (1) to (5).

[0077] In this embodiment, a three-blade agitator is provided at the bottom of the mixing tank, a heat exchange device and several three-blade agitators are provided in the reactor; a three-blade agitator is provided inside the extractor; the separator is in the shape of an inverted cone and has discharge pipes at the top and bottom.

[0078] The above embodiments are merely preferred embodiments of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. All technical solutions that fall within the scope of protection of the present invention are within the scope of protection of the present invention. It should be noted that improvements and modifications that can be made by a person skilled in the art without departing from the principles of the present invention are also considered to be within the scope of protection of the present invention.

Claims

1. A method for removing sulfur-containing organic compounds from oil products using a molybdenum phosphide composite catalyst, characterized in that: The method comprises catalytically oxidizing sulfur organic compounds in oil products using a molybdenum phosphide composite catalyst; the molybdenum phosphide composite catalyst comprises nitrogen-phosphorus co-doped carbon nanosheets, on which molybdenum phosphide nanoparticles are loaded; the mass ratio of the molybdenum phosphide particles to the nitrogen-phosphorus co-doped carbon nanosheets in the molybdenum phosphide composite catalyst is 2-40; the mass fraction of nitrogen in the nitrogen-phosphorus co-doped carbon nanosheets is 2%-8% of the nitrogen-phosphorus co-doped carbon nanosheets, and the mass fraction of phosphorus is 4%-15% of the nitrogen-phosphorus co-doped carbon nanosheets; and the preparation method of the molybdenum phosphide composite catalyst comprises the following steps: S1, preparing a molybdenum-based metal-organic framework into a molybdenum-based metal-organic framework dispersion, adding a melamine dispersion, and stirring to prepare a molybdenum-based metal-organic framework / melamine dispersion; S2, mixing the molybdenum-based metal organic framework / melamine dispersion obtained in step S1 with the phytic acid solution to perform a solvothermal reaction, centrifuging, and freeze-drying to obtain a molybdenum phosphide composite catalyst precursor powder; S3. calcining the molybdenum phosphide composite catalyst precursor powder obtained in step S2 in an argon atmosphere to obtain a molybdenum phosphide composite catalyst.

2. The method for removing sulfur-containing organic compounds in oil products using a molybdenum phosphide composite catalyst according to claim 1, wherein: In step S1, the concentration of the molybdenum-based metal organic framework dispersion is 25 to 200 g / L; the concentration of the melamine dispersion is 30 to 50 g / L; and the stirring time is 0.5 to 2 h; In step S2, the mass fraction of the phytic acid solution is 16% to 20%; the volume ratio of the phytic acid solution to the molybdenum-based metal organic framework / melamine dispersion is 0.5 to 0.8:1; the solvent thermal reaction temperature is 60 to 80° C.; the solvent thermal reaction time is 12 to 24 hours; and the freeze drying time is 12 to 24 hours. In step S3, the calcination temperature is 800-900°C; and the calcination heating rate is 2-10°C / min.

3. The method for removing sulfur-containing organic compounds in oil products using a molybdenum phosphide composite catalyst according to claim 2, wherein: The preparation method of the molybdenum-based metal organic framework comprises the following steps: (1) adding molybdenum trioxide to water and stirring to obtain a molybdenum trioxide dispersion; the mass ratio of the molybdenum trioxide to water is 1:70-100; and the stirring time is 0.5-2 h; (2) adding imidazole to the molybdenum trioxide dispersion obtained in step (1) to carry out a hydrothermal reaction, washing, and drying to obtain a molybdenum-based metal organic framework; the mass ratio of imidazole to molybdenum trioxide is 0.48 to 0.50:1; the hydrothermal reaction is carried out at a temperature of 100 to 140°C; the hydrothermal reaction time is 12 to 24 hours; the washing is carried out by washing the filtered product 3 to 6 times with ultrapure water; the drying process is carried out under vacuum conditions; and the drying temperature is 40 to 80°C.

4. The method for removing sulfur-containing organic compounds from oil products using a molybdenum phosphide composite catalyst according to any one of claims 1 to 3, characterized in that: The method uses a molybdenum phosphide composite catalyst to catalytically oxidize sulfur organic compounds in oil products, comprising the following steps: mixing the molybdenum phosphide composite catalyst, acetonitrile and hydrogen peroxide with the sulfur organic compound oil products, performing physical mixing and heating to start the catalytic oxidation reaction, and extracting and separating to complete the removal of the sulfur organic compounds in the oil products.

5. The method for removing sulfur-containing organic compounds in oil products using a molybdenum phosphide composite catalyst according to claim 4, characterized in that: The molybdenum phosphide composite catalyst is used in an amount of 1 to 3 g per liter of sulfur-containing organic compound oil; the molar ratio of hydrogen peroxide to sulfur in the sulfur-containing organic compound oil is 6:1; the sulfur-containing organic compound in the sulfur-containing organic compound oil is at least one of dibenzothiophene and 4,6-dimethyldibenzothiophene; the concentration of the sulfur-containing organic compound in the sulfur-containing organic compound oil is 1000 to 2000 ppm; the catalytic oxidation reaction is carried out at a temperature of 50 to 70° C.; and the catalytic oxidation reaction time is 30 to 60 minutes.

6. The method for removing sulfur-containing organic compounds in oil products using a molybdenum phosphide composite catalyst according to claim 5, characterized in that: An oxidative desulfurization reaction device is used to desulfurize high-sulfur fuel oil; the oxidative desulfurization reaction device includes a mixing tank, a reactor, an extractor, a separator, a buffer tank, and a finished product tank. The desulfurization treatment of high-sulfur fuel oil includes the following steps: 1) Add molybdenum phosphide composite catalyst, high sulfur fuel oil, extractant and oxidant into a mixing tank and mix them evenly; 2) pumping the uniformly mixed solution in step 1) into the reactor to carry out oxidative desulfurization reaction; 3) transporting the reaction product solution obtained by the oxidative desulfurization reaction in step 2) to an extractor for extraction treatment; 4) transferring the mixed solution obtained after the extraction treatment in step 3) to a separator and allowing it to settle naturally for 10 to 30 minutes to obtain an upper oil phase and a lower mixed phase of extractant, unconsumed oxidant, and catalyst; 5) The upper oil phase separated in step 4) is sequentially transported to a buffer tank and a finished product tank to obtain clean fuel oil, and the lower mixed phase is returned to the mixing tank and mixed again with the high-sulfur fuel oil to complete the continuous desulfurization treatment of the high-sulfur fuel oil.

7. The method according to claim 6, characterized in that A three-leaf stirrer is provided at the bottom of the mixing tank, a heat exchange device and several three-leaf stirrers are provided in the reactor; a three-leaf stirrer is provided inside the extractor; the separator is in an inverted cone shape and is provided with discharge pipes at the upper and lower parts.

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