Process for the gas-solid phase synthesis of acenaphthylene using oxygen-deficient air

Abstract

The present invention provides a process for the gas-solid synthesis of acenaphthylene with lean oxygen air. The method uses industrial acenaphthene as a raw material, reacts in a lean oxygen atmosphere in the presence of a vanadium-based catalyst, continuously supplements air or oxygen-rich gas during the reaction to maintain oxygen at a certain concentration, and at the same time treats and recycles the unreacted gas. This not only reduces the emissions of reaction gases, relieves the pressure of treating the three wastes, but also can weaken over-oxidation and reduce the preparation cost, having broad application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical engineering, and particularly relates to a process for synthesizing acenaphthylene by gas-solid phase reaction with oxygen-deficient air. Background Art

[0002] Industrial acenaphthene is white or slightly yellowish needle-shaped crystals. Nitrated industrial acenaphthene can produce nitroacenaphthene, and oxidized industrial acenaphthene can produce 1,8-naphthalic anhydride and acenaphthenequinone, which can be used in the synthesis of dyes. Dehydrogenated acenaphthene can produce acenaphthylene, and acenaphthylene resin can be prepared. It can also be used in the preparation of fluorescent pigments and, in recent years, in the production of high-performance water reducing agents.

[0003] The common production method for producing acenaphthylene from existing industrial acenaphthene is as follows: Industrial acenaphthene is put into a melting kettle and heated with indirect steam until completely melted. Compressed air is used to press the liquid acenaphthene into a spiral gasification mixer, where it is gasified by steam heating. The direct steam and acenaphthene vapor are mixed and enter a superheater, where they are superheated to 450 ± 20 °C and then enter a dehydrogenation reactor for catalytic dehydrogenation reaction. Then, it is condensed and dried to obtain crude acenaphthylene. The crude acenaphthylene is dissolved in ethanol to remove carbides and mechanical impurities, and then cooled, crystallized, and dried to obtain the finished product. The catalyst used is zinc oxide (85%), calcium oxide (5%), potassium sulfate (5%), potassium chromate (3%), and potassium hydroxide (2%).

[0004] However, this production method often causes excessive oxidation due to too high oxygen content, resulting in low yield and content of the produced acenaphthylene. In an oxygen-free atmosphere, the catalyst has no catalytic effect. At the same time, there are disadvantages such as a large amount of reaction gas emissions, high pressure for treating three wastes, high environmental load, and low reaction safety. Summary of the Invention

[0005] Based on the above technical background, the inventor of the present invention made unremitting efforts and found that: Using industrial acenaphthene as the raw material, preparing acenaphthylene under an oxygen-deficient atmosphere by controlling the oxygen concentration can not only weaken the excessive oxidation reaction and improve the safety of the reaction system, but also, during the preparation process, with the assistance of the vanadium-based catalyst prepared by the present invention, further improve the yield of acenaphthylene in the oxygen-deficient atmosphere. Treating the unreacted gas and recycling it can reduce the reaction gas emissions, reduce the pressure for treating three wastes, and significantly reduce the industrial preparation cost, having good application prospects, thus completing the present invention.

[0006] The first aspect of the present invention is to provide a process for synthesizing acenaphthylene by gas-solid phase reaction with oxygen-deficient air. This method uses industrial acenaphthene as the raw material and reacts under an oxygen-deficient atmosphere in the presence of a vanadium-based supported catalyst.

[0007] The method includes the following steps:

[0008] Step 1: Heat and melt industrial acenaphthene, preheat the oxygen-deficient gas, and then mix to obtain a mixed gas;

[0009] Step 2: Feed the mixed gas into a fixed-bed reactor and carry out the reaction in the presence of a vanadium-based supported catalyst;

[0010] Step 3: Collect the product, treat the reaction gas, and recycle it.

[0011] The process for the synthesis of acenaphthylene by the gas-solid phase reaction with oxygen-deficient air provided by the present invention has the following advantages:

[0012] In the industrial production of acenaphthylene from acenaphthene, it is a dehydrogenation process. Excessive oxygen content will cause over-oxidation, and without an oxygen-free atmosphere, the catalyst has no catalytic effect. Therefore, to enhance the dehydrogenation effect, the present invention weakens the oxidation reaction and releases the gas by controlling the oxygen-deficient environment. At the same time, the released gas is treated through environmental protection facilities and recycled, greatly reducing the emission of reaction gases. This process not only reduces the pressure of treating the three wastes and is environmentally friendly, but also significantly improves the safety of the entire reaction system in an oxygen-deficient environment. Description of the Drawings

[0013] Figure 1 Shows the process flow chart of the process for the synthesis of acenaphthylene by the gas-solid phase reaction with oxygen-deficient air according to the present invention;

[0014] Figure 2 Shows the gas chromatogram of the acenaphthylene prepared in Example 1 of the present invention.

[0015] Description of the Reference Numerals in the Drawings

[0016] 1 - Gas buffer tank;

[0017] 2 - Mixer;

[0018] 3 - Fixed-bed reactor;

[0019] 4 - Trap;

[0020] 5 - Absorption tower;

[0021] 6 - Water remover;

[0022] 7 - Gas-liquid separator. Detailed Embodiments

[0023] The present invention will be described in detail below, and its features and advantages will become clearer and more definite with these descriptions.

[0024] In the prior art, air or carbon dioxide is often used for the preparation of acenaphthylene. Using air for the preparation of acenaphthylene will cause over-oxidation, resulting in low acenaphthylene yield and large emissions of reaction gases. While using carbon dioxide for the preparation will lead to large emissions of greenhouse gases and great environmental protection pressure.

[0025] The first aspect of the present invention lies in providing a process for synthesizing acenaphthylene by gas-solid phase reaction with oxygen-deficient air. This method uses industrial acenaphthene as the raw material, reacts in an oxygen-deficient atmosphere in the presence of a vanadium-based supported catalyst, continuously replenishes air during the reaction process, and recycles the unreacted gas after treatment. As shown in Figure 1 . It not only avoids over-oxidation caused by too high oxygen concentration and improves the yield of acenaphthylene, but also circumvents the drawback of large gas emissions through the recycling of gas, reduces the pressure of treating three wastes and production costs.

[0026] Specifically, the method includes the following steps:

[0027] Step 1: Heat and melt industrial acenaphthene, preheat the oxygen-deficient gas, and then mix to obtain a mixed gas;

[0028] Step 2: Pass the mixed gas into a fixed-bed reactor and react in the presence of a vanadium-based supported catalyst;

[0029] Step 3: Collect the product, treat the reaction gas, and then recycle it.

[0030] The following is a specific description and explanation of this step.

[0031] Step 1: Heat and melt industrial acenaphthene, preheat the oxygen-deficient gas, and then mix to obtain a mixed gas.

[0032] Industrial acenaphthene is heated to 90 - 110 °C for melting, preferably heated to 95 - 105 °C, and more preferably heated to 100 °C.

[0033] The feeding rate of industrial acenaphthene is 50 - 80 kg / h, preferably 55 - 60 kg / h.

[0034] The oxygen-deficient gas includes air and one or more of nitrogen, carbon dioxide, helium, water vapor, and argon.

[0035] Preferably, the oxygen-deficient gas includes air and one or more of nitrogen, helium, and argon.

[0036] More preferably, the oxygen-deficient gas is a mixed gas of air and nitrogen. The inventors have found that using the above gas mixed with air as the oxygen-deficient gas of the present invention can not only improve the safety of the reaction process, especially the mixed gas of nitrogen and air is also helpful for suppressing over-oxidation, improving the catalytic effect of the catalyst, increasing the yield of acenaphthylene, but also avoiding the greenhouse effect.

[0037] The mixing of the oxygen-deficient gas is carried out in gas buffer tank 1, wherein the flow rate of air is 1400 - 1700 m 3 / h, preferably 1500 - 1600 m 3 / h.

[0038] During the reaction process, the total circulation amount of the reaction gas is 2200 - 2600 m 3 / h, preferably 2300 - 2500 m 3 / h.

[0039] Specifically, the volume fraction of air in the oxygen - depleted gas is 40% - 80%, preferably 50% - 70%, and more preferably 55% - 67%.

[0040] If the oxygen content in the oxygen - depleted gas is too high, the yield of acenaphthylene will decrease due to over - oxidation. If the oxygen content is too low, the catalytic effect of the catalyst will be inhibited, which is not conducive to the progress of the reaction. Through experiments, it is found that when the volume fraction of air in the oxygen - depleted gas is within the above range, it is beneficial to increase the yield of acenaphthylene.

[0041] The pre - heating temperature is 200 - 260 °C, preferably 220 - 240 °C, and more preferably 230 °C.

[0042] The mixing is carried out in mixer 2. In the mixed gas, the molar ratio of the oxygen - depleted gas to industrial acenaphthene is (200 - 400):1, preferably (250 - 350):1, and more preferably (270 - 280):1.

[0043] The molten industrial acenaphthene and the oxygen - depleted gas are mixed in mixer 2. The mixing and the pipeline between mixer 2 and fixed - bed reactor 3 are carried out under heating. The heating temperature is the same as the pre - heating temperature of the oxygen - depleted gas. Most of the industrial acenaphthene is vaporized by the high - flow oxygen - depleted gas and enters the fixed - bed reactor in the form of unsaturated steam.

[0044] Step 2: The mixed gas is introduced into the fixed - bed reactor and reacts in the presence of a vanadium - based supported catalyst.

[0045] The reaction equation for preparing acenaphthylene from industrial acenaphthene in the present invention is as follows:

[0046]

[0047] The industrial acenaphthene and the oxygen - depleted gas are mixed in mixer 2 and then enter fixed - bed reactor 3 through a pipeline. There is a catalyst bed layer in fixed - bed reactor 3 for catalyzing the reaction. The catalyst bed layer in the present invention is provided with a vanadium - based supported catalyst.

[0048] The vanadium - based supported catalyst includes an active component and a carrier. The active component uses vanadium as the main catalyst and one or more of potassium, tin, and cobalt as co - catalysts, preferably using potassium, tin, and cobalt as co - catalysts.

[0049] The active component in the present invention can be composed of V a Sn b K c Cod It is expressed that, where a = 1, b is 0.5 to 1.0, c is 0.3 to 0.8, and d is 0.05 to 0.3. Preferably, a = 1, b is 0.7 to 0.8, c is 0.5 to 0.6, and d is 0.1 to 0.15.

[0050] When potassium, tin, and cobalt are used as cocatalysts, this vanadium-based supported catalyst has the highest catalytic activity under the above-mentioned oxygen-deficient atmosphere, which is beneficial to the improvement of the industrial acenaphthene conversion rate and the high yield of acenaphthylene.

[0051] The carrier of this vanadium-based supported catalyst is one or more of silica, alumina, diatomite, activated carbon, and pumice, and preferably pumice.

[0052] The specific surface area of the vanadium-based catalyst described in the present invention is 10 to 50 m 2 / g, and the service life is 10800 to 21600 h. This vanadium-based catalyst has a large specific surface area and a long service life. When used in the preparation of acenaphthylene, it can not only improve the yield of acenaphthylene, but also has a long service life of the catalyst, which can greatly reduce the production cost of industrial preparation of acenaphthylene.

[0053] This vanadium-based supported catalyst is prepared from raw materials including a vanadium source, and the vanadium source is selected from one or more of ammonium metavanadate, vanadium trichloride, and vanadic acid, and preferably ammonium metavanadate.

[0054] The raw materials also include one or more of a potassium source, a tin source, and a cobalt source. The potassium source is selected from one or more of potassium sulfate, potassium nitrate, and potassium chlorate, and preferably potassium sulfate.

[0055] The tin source is selected from one or more of stannous chloride, tin tetrachloride, and tin sulfide, and preferably stannous chloride.

[0056] The cobalt source is selected from one or more of cobalt acetate, cobalt nitrate, and cobalt sulfate, and preferably cobalt acetate.

[0057] According to a preferred embodiment of the present invention, this vanadium-based catalyst is prepared by the following steps:

[0058] Step a: After adding the vanadium source and the tin source to the oxalic acid solution and mixing them, then adding the potassium source and the cobalt source thereto and stirring and mixing to obtain a mixed solution;

[0059] Step b: Adding the carrier to the mixed solution, concentrating and shaping it, and then sintering to obtain the vanadium-based supported catalyst.

[0060] In step a, the oxalic acid solution is prepared by dissolving oxalic acid in a solvent, and the solvent is preferably water.

[0061] The mass ratio of oxalic acid to the solvent is 1:(5 to 10), and preferably 1:(7 to 9).

[0062] The mixing temperature is 60 to 90 °C, preferably 70 to 80 °C.

[0063] In the present invention, after adding a vanadium source and a tin source to an oxalic acid solution, stirring and mixing are carried out. The stirring time is 0.5 to 2 h, preferably 1 h.

[0064] The mass ratio of the vanadium source, the tin source and oxalic acid is (0.2 to 0.9):(0.4 to 1):1, and the preferred mass ratio is (0.4 to 0.6):(0.6 to 0.8):1.

[0065] After mixing evenly, a potassium source and a cobalt source are added thereto for stirring and mixing. The stirring and mixing time is 1 to 3 h, preferably 2 h.

[0066] The mass ratio of the potassium source, the cobalt source and oxalic acid is (0.1 to 0.5):(0.03 to 0.1):1, and the preferred mass ratio is (0.2 to 0.3):(0.06 to 0.07):1.

[0067] In step b, the particle size of the carrier is 1 to 10 mm, preferably 4 to 7 mm.

[0068] The carrier accounts for 75 to 85% of the mass of the vanadium-based supported catalyst, preferably 78 to 82%, more preferably 79 to 81%.

[0069] Before adding, the carrier is preferably pickled to remove a small amount of metal impurities existing inside the pumice, which is beneficial to improving the catalytic efficiency of the catalyst.

[0070] The concentration and shaping refer to heating the above-mentioned mixed solution until there is basically no remaining liquid.

[0071] The sintering is preferably carried out in two steps in a muffle furnace, including low-temperature sintering and high-temperature sintering.

[0072] The low-temperature sintering temperature is 300 to 400 °C, preferably 330 to 370 °C, more preferably 340 to 360 °C.

[0073] The low-temperature sintering time is 1 to 5 h, preferably 2 to 4 h, more preferably 3 h.

[0074] The high-temperature sintering temperature is 500 to 800 °C, preferably 550 to 750 °C, more preferably 600 to 700 °C.

[0075] The high-temperature sintering time is 5 to 15 h, preferably 7 to 13 h, more preferably 9 to 11 h.

[0076] The vanadium-based catalyst used in the present invention not only has a long service life, greatly reducing the cost of industrial preparation, but also when applied to the oxygen-deficient preparation of acenaphthylene, it can improve the yield and content of acenaphthylene. Especially when the oxygen-deficient gas is a mixed gas of air and nitrogen, the yield of acenaphthylene is further increased under the catalytic conditions of the vanadium-based catalyst.

[0077] The reaction pressure is 0.01 - 0.07 MPa, preferably 0.02 - 0.05 MPa, and more preferably 0.02 - 0.04 MPa.

[0078] The reaction temperature is 300 - 450 °C, preferably 320 - 400 °C, and more preferably 340 - 370 °C.

[0079] The reaction time is 0.1 - 1 s, preferably 0.2 - 0.7 s, and more preferably 0.3 - 0.4 s.

[0080] If the reaction temperature is too low or the reaction time is too short, the activity of the catalyst cannot be fully stimulated, or the contact time between industrial acenaphthene and the catalyst is too short, resulting in insufficient reaction and a decrease in the yield of acenaphthylene. If the reaction temperature is too high or the reaction time is too long, on the one hand, the reaction rate is too high and the reaction is difficult to control, and on the other hand, it will cause over-oxidation, resulting in an increase in by-products and also a decrease in the yield of acenaphthylene.

[0081] Step 3: Collect the product, and after treating the reaction gas, recycle it.

[0082] The product desorbed from the catalyst surface enters the trap 4 through the fixed-bed reactor 3 with the gas, and the trapped acenaphthylene is collected.

[0083] The treatment includes absorption and water removal. Absorption is mainly used to absorb acenaphthylene in the reaction gas. Since the melting point of acenaphthylene is only 92 - 93 °C, acenaphthylene is easily entrained in a large amount of gas. The dust (the dust includes a very small amount of products and by-products) that is not completely trapped by the trapping equipment is absorbed through the absorption tower, and the purpose of the water separator is to reduce the moisture in the carrier gas. Specifically, the reaction gas passes through the absorption tower 5 and the water separator 6 in sequence and enters the gas-liquid separator 7.

[0084] Part of the reaction gas introduced into the gas-liquid separator 7 enters the tail gas treatment system, and the other part of the gas re-enters the gas buffer tank through the pipeline to participate in the next reaction, realizing the efficient recycling of the gas.

[0085] The yield of acenaphthylene obtained by the process method of the present invention is 94% - 99%, the conversion rate of industrial acenaphthene is 96% - 99.9%, and the purity of acenaphthylene is 95% - 99.9%.

[0086] The beneficial effects of the present invention:

[0087] (1) The process for synthesizing acenaphthylene provided by the present invention has strong operability, effectively solves the problem of high industrial three wastes, improves the safety of the reaction system, reduces production costs, and can realize industrial production;

[0088] (2) The reaction system of the present invention is mainly nitrogen, mixed with air, and the oxygen concentration is controlled within a lower range. This not only improves the safety of the reaction system, but also weakens the oxidation reaction by controlling the reaction system to be an oxygen-deficient environment, thereby improving the product yield;

[0089] (3) By discharging the off-gas and treating the off-gas through environmental protection facilities, the present invention greatly reduces the emission of reaction gases;

[0090] Examples

[0091] The present invention will be further elaborated through specific examples below. These examples are only for illustrating the present invention and are not used to limit the scope of the present invention.

[0092] Example 1

[0093] 46 kg of oxalic acid was added to 360 kg of deionized water, and the temperature was raised to 75 °C and stirred until completely dissolved. 23 kg of ammonium metavanadate and 33.1 kg of stannous chloride were slowly added to the above solution respectively, and stirred for 1 h. Then, 9.7 kg of potassium sulfate and 2.9 kg of cobalt acetate were added to the above solution, and stirred for 2 h. The above solution was added to 5 mm * 5 mm pumice that had been screened and pickled, stirred evenly, concentrated to form, taken out and placed in a muffle furnace, gradually heated to 350 °C and calcined for 3 h, then heated to 650 °C and kept warm for 10 h. After natural cooling to room temperature, the vanadium-based supported catalyst V1Sn 3 K 0.75 K 0.57 Co 0.13 .

[0094] Industrial acenaphthene was heated to 100 °C to melt. Nitrogen with a volume fraction of 35% and air with a volume fraction of 65% were preheated to 230 °C in the gas buffer tank 1, mixed with industrial acenaphthene in the mixer 2, and then introduced into the fixed-bed reactor 3. The reaction system pressure was set to 0.02 - 0.04 MPa, and the residence time in the fixed-bed reactor 3 was 0.3 s. The above mixture was reacted with the supported vanadium-based catalyst at a reaction temperature of 355 ± 5 °C. The product desorbed from the catalyst surface directly entered the trap 4 with the reaction gas, as Figure 1As shown, the collected acenaphthylene is collected. The reaction gas sequentially enters the absorption tower 5 and the water remover 6 and then enters the gas-liquid separator 7. A part of the treated gas is re-entered into the gas buffer tank 1 after treatment, mixed with air and then continuously used for the preparation of acenaphthylene. Another part of the purge gas enters the tail gas treatment system. In this system, the feeding rate of industrial acenaphthene is 60 kg / h, the initial air flow rate is 1560 m 3 / h, and the nitrogen flow rate is 840 m 3 / h. The molar ratio of the gas to industrial acenaphthene is 271:1. The reaction gas is recycled, and the total recycling amount of the reaction gas is constantly 2400 m 3 / h. The oxygen concentration in the reaction gas is monitored in real time by an oxygen analyzer, and the oxygen concentration is controlled at 13-14%. After the reaction is completed, it is measured that the conversion rate of industrial acenaphthene is 99.6%, the yield of acenaphthylene is 98.1%, and the content of acenaphthylene is 99.6%.

[0095] Example 2

[0096] Acenaphthylene is prepared in a manner similar to Example 1, except that: argon with a volume fraction of 35% and air with a volume fraction of 65% are preheated at 230 °C in the gas buffer tank 1. After the reaction is completed, it is measured that the conversion rate of industrial acenaphthene is 97.6%, the yield of acenaphthylene is 96.2%, and the content of acenaphthylene is 97.1%

[0097] Example 3

[0098] Acenaphthylene is prepared in a manner similar to Example 1, except that: industrial acenaphthene is heated to 100 °C for melting, and nitrogen with a volume fraction of 45% and air with a volume fraction of 55% are preheated at 230 °C in the gas buffer tank 1. After the reaction is completed, it is measured that the conversion rate of industrial acenaphthene is 96.1%, the yield of acenaphthylene is 94.8%, and the content of acenaphthylene is 95.6%.

[0099] Comparative Example

[0100] Acenaphthylene is prepared in a manner similar to Example 1, except that: the catalyst is the aluminum-chromium-based heterogeneous catalyst used in Example 1 of Patent CN101955407A. It is measured that the conversion rate of industrial acenaphthene is 71.0%, the yield of acenaphthylene is 52.3%, and the content of acenaphthylene is 59.7%.

[0101] Experimental Example

[0102] Gas Chromatography Test in Experimental Example 1

[0103] The specific test process is as follows: Sample preparation

[0104] Accurately weigh 0.0010 g (±0.0003) of the product prepared in Example 1 as a sample into a 1 ml sample dissolution bottle, add 1 ml of solvent (methanol), and place it in an ultrasonic wave to oscillate until it is completely dissolved. Injection volume: 0.5 ul.

[0105] The detection is carried out according to the following test conditions:

[0106] Chromatographic column: InertCap 5;

[0107] Column temperature: 180 °C, 30 min;

[0108] Vaporization chamber temperature: 260 °C;

[0109] Detector temperature: 260 °C;

[0110] Make-up gas flow rate: 30.0 ml / min;

[0111] Hydrogen flow rate: 40.0 ml / min;

[0112] Air flow rate: 400 ml / min;

[0113] Split ratio: 50:1;

[0114] The test results are as Figure 2 shown.

[0115] From Figure 2 it can be seen that the purity of the product prepared in Example 1 is 99.651%. It shows that the acenaphthylene prepared by the preparation method described in the present invention has a high purity.

[0116] The present invention has been described in detail above in conjunction with specific embodiments and exemplary examples, but these descriptions should not be construed as limiting the present invention. Those skilled in the art understand that without departing from the spirit and scope of the present invention, various equivalent substitutions, modifications or improvements can be made to the technical solutions and their implementation manners of the present invention, and these all fall within the scope of the present invention. The protection scope of the present invention shall be subject to the appended claims.

Claims

1. A process for the gas-solid phase synthesis of acenaphthylene from lean oxygen air, characterized in that, The method uses industrial acenaphthene as raw material, reacts in an oxygen-deficient atmosphere in the presence of a vanadium-based supported catalyst. The method comprises the following steps: Step 1: Heat and melt industrial acenaphthene, preheat the oxygen-deficient gas, and then mix them to obtain a mixed gas. The oxygen-deficient gas includes air and one or more of nitrogen, carbon dioxide, helium, water vapor, and argon. The volume fraction of air in the oxygen-deficient gas is 40% - 80%. Step 2: Feed the mixed gas into a fixed-bed reactor and carry out the reaction in the presence of a vanadium-based supported catalyst. The reaction pressure is 0.01 - 0.07 MPa, the reaction temperature is 300 - 450 °C, and the reaction time is 0.1 - 1 s. The vanadium-based supported catalyst includes an active component and a support. The active component uses vanadium as the main catalyst and one or several of potassium, tin, and cobalt as co-catalysts. The active component is represented by V a Sn b K c Co d , where a = 1, b is 0.5 - 1.0, c is 0.3 - 0.8, and d is 0.05 - 0.

3. The specific surface area of the vanadium-based supported catalyst is 10 - 50 m 2 / g; Step 3: Collect the product, and recycle it after treating the reaction gas.

2. The method according to claim 1, characterized in that In Step 1, The oxygen-deficient gas is a mixed gas of air and nitrogen.

3. The method according to claim 1, characterized in that, In Step 1, the volume fraction of air in the oxygen-deficient gas is 50% - 70%.

4. The method according to claim 1, wherein In Step 1, the molar ratio of the oxygen-deficient gas to industrial acenaphthene is (200 - 400):

1.

5. The method according to claim 1, characterized in that In Step 2, the active component consists of V a Sn b K c Co d represented by Wherein, a = 1, b is 0.7 - 0.8, c is 0.5 - 0.6, and d is 0.1 - 0.

15.

6. The method according to claim 1, characterized in that, In Step 2, The service life of the vanadium-based supported catalyst is 10800 - 21600 h; The carrier of the vanadium-based supported catalyst is one or more of silica, alumina, diatomite, activated carbon, and pumice.

7. The method according to any one of claims 1 to 6, characterized in that, In Step 2, the vanadium-based catalyst is prepared through the following steps: Step a: Add a vanadium source and a tin source into an oxalic acid solution and mix them, then add a potassium source and a cobalt source thereto and stir to mix, obtaining a mixed solution; Step b: Add the carrier into the mixed solution, concentrate and form it, and then sinter it to obtain the vanadium-based supported catalyst.

8. The method according to claim 1, characterized in that, In Step 2, The reaction pressure is 0.02 - 0.05 MPa, the reaction temperature is 320 - 400 °C, and the reaction time is 0.2 - 0.7 s.

9. The method according to claim 8, characterized in that, In Step 2, The reaction pressure is 0.02 - 0.04 MPa, the reaction temperature is 340 - 370 °C, and the reaction time is 0.3 - 0.4 s.

10. The method according to claim 1, wherein The yield of acenaphthylene obtained by this method is 94% - 99%, the conversion rate of industrial acenaphthene is 96% - 99.9%, and the purity of acenaphthylene is 95% - 99.9%.

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