Method for enriching polycyclic aromatic hydrocarbons in a hydrocarbon oil, method for extracting pure anthracene from a hydrocarbon oil and separation system

Abstract

The application discloses a method for enriching polycyclic aromatic hydrocarbons in hydrocarbon oil, a method for extracting pure anthracene from the hydrocarbon oil and a separation system, and the method for enriching polycyclic aromatic hydrocarbons in hydrocarbon oil comprises the following steps: S1, catalytic cycle oil is subjected to rectification cutting in a rectification tower to obtain a three-ring aromatic hydrocarbon-rich fraction segment with a distillation range of 310-365 DEG C; S2, the three-ring aromatic hydrocarbon-rich fraction segment is added into a first crystallizer to perform cooling crystallization to obtain a first crystal slurry; and S3, the first crystal slurry is subjected to solid-liquid separation to obtain three-ring aromatic hydrocarbon-rich first crystals and a first mother liquor. The method combines rectification and crystallization to enrich polycyclic aromatic hydrocarbons from oil products, obtain crude anthracene products and further separate and purify the crude anthracene products to obtain pure anthracene products. The method provided by the application expands the production raw materials of polycyclic aromatic hydrocarbons, reduces the raw material cost, provides an outlet for heavy oil lightening products, is low-carbon and high-efficiency, reasonable and feasible, and has good economic and social benefits.

Description

Technical Field

[0001] This invention relates to a method for separating mixtures, and more specifically, to a method for separating and purifying polycyclic aromatic hydrocarbons from oil products. Background Technology

[0002] Anthracene, phenanthrene, and other polycyclic aromatic hydrocarbons (PAHs) are important chemical raw materials, widely used in dyes, pharmaceuticals, plastics, pesticides, papermaking, and optoelectronic materials. With the development of fine chemicals and advancements in organic synthesis technology, the demand for PAHs is gradually increasing. Currently, 90% of the anthracene and phenanthrene raw materials on the market are refined from coal tar produced through coal chemical processes. Considering the increasing national environmental protection requirements, coke production may gradually decline, and the cost of coal tar may rise significantly in the future.

[0003] With the increasing demand for lighter oil products and the trend towards heavier crude oil, the proportion of heavy oil products such as catalytic cracking light diesel, catalytic cracking intermediate cycle oil, and catalytic recycle oil in heavy oil processing is rising, and their production is increasing year by year. However, these products cannot yet be converted into finished products, making their deep processing a focus and an inevitable trend in the refining industry.

[0004] Catalytic cracking light diesel oil contains approximately 4%-6% tricyclic and higher polycyclic aromatic hydrocarbons (PAHs). On the one hand, these components lead to problems in hydrotreating and catalytic cracking, including cycle mismatch, high hydrotreating pressure, high hydrogen consumption, difficult conversion, low efficiency, and high cost. On the other hand, these PAHs, mainly anthracene and phenanthrene, are important intermediates in fine chemicals, organic chemicals, and pharmaceuticals, possessing high economic value. Extracting PAHs from catalytic cracking light diesel oil and other petroleum products is significant for the conversion of catalytic cracking light diesel oil into aromatics and the development of new products. Besides catalytic cracking light diesel oil, the catalytic cycle oil and catalytic recycle oil, which are byproducts of petroleum catalytic cracking, contain even higher levels of PAHs, with PAH content exceeding 35% in both cases. Therefore, they are also ideal feedstocks for PAH extraction.

[0005] The content of tricyclic and higher-order polycyclic aromatic hydrocarbons (PAHs) in catalytic cracking light diesel oil, catalytic cracking intermediate cycle oil, and catalytic recycle oil is higher than or close to that in ordinary coal tar, and the sources are abundant. Using these as raw materials for the purification of anthracene, phenanthrene, and other chemical products has excellent economic and social benefits and promising prospects for widespread application. However, no patent reports have been found regarding the extraction of anthracene, phenanthrene, and other PAHs from oil products. Therefore, developing technologies for extracting PAHs from oil products is of significant strategic importance.

[0006] Currently, almost all anthracene and phenanthrene raw materials on the market are refined from coal tar produced by coal chemical industry. The mainstream technical route in China is to prepare crude anthracene from anthracene oil, followed by separation and refining of the crude anthracene. CN1487910A discloses a method for preparing refined anthracene from coal tar. Through multi-stage melt crystallization and sweating, crude anthracene with an anthracene content of 63% is prepared, and high-purity anthracene is obtained by distillation. CN103232318A discloses a method and apparatus for producing refined anthracene, refined carbazole, and phenanthrene products from anthracene oil as raw material, providing a process for obtaining refined anthracene with a purity of over 95% using anthracene oil as raw material through multi-stage crystallization and separation + dispersed distillation.

[0007] Baosteel has introduced anthracene oil processing technology from the French company BEFS. Using anthracene oil as raw material, and employing a combination of crystallization and depressurization distillation, it can produce 96% refined anthracene, making it one of the most advanced anthracene oil processing technologies in China. In summary, based on current technology, there are currently no reports on the extraction of anthracene and other polycyclic aromatic hydrocarbons from oil products. Summary of the Invention

[0008] One of the technical problems solved by this invention is to address the issue of the single source of polycyclic aromatic hydrocarbons in the prior art, and to provide a method for extracting polycyclic aromatic hydrocarbons from hydrocarbon oil fractions.

[0009] The second technical problem solved by this invention is to provide a method for separating and refining polycyclic aromatic hydrocarbon products from hydrocarbon oil fractions.

[0010] In a first aspect, the present invention provides a method for enriching polycyclic aromatic hydrocarbons in hydrocarbon oil, comprising the following steps:

[0011] S1. The catalytic cycle oil is distilled and cut in a distillation column to obtain a tricyclic aromatic hydrocarbon-rich fraction with a distillation range of 310-365℃.

[0012] S2. The tricyclic aromatic hydrocarbon-rich fraction is added to the first crystallizer for cooling and crystallization to obtain the first crystal slurry;

[0013] S3. Separate the first crystal slurry into solid and liquid phases to obtain a first crystal rich in polycyclic aromatic hydrocarbons and a first mother liquor.

[0014] The first crystal is a crude anthracene product enriched with polycyclic aromatic hydrocarbons.

[0015] In a second aspect, the present invention provides a method for extracting refined anthracene from hydrocarbon oils, wherein the above-mentioned method for enriching polycyclic aromatic hydrocarbons in hydrocarbon oils is used to obtain a first crystal rich in polycyclic aromatic hydrocarbons; further comprising:

[0016] S4. The first crystal is mixed with the first solvent and then crystallized in the second crystallizer to obtain the second crystal slurry. After solid-liquid separation, the second crystal and the second mother liquor rich in phenanthrene are obtained. The second crystal is washed and dried to obtain the secondary crystal.

[0017] S5. The secondary crystals are mixed with the second solvent and then crystallized in the third crystallizer to obtain the third crystal slurry. The third crystal slurry is separated into a third crystal and a third mother liquor. The third crystal is washed and dried to obtain the refined anthracene product.

[0018] Thirdly, the present invention provides a separation system for extracting refined anthracene from hydrocarbon oils, and a method for extracting refined anthracene from hydrocarbon oils as described above. The system comprises a distillation column, a first crystallization unit, a second crystallization unit, and a third crystallization unit connected in sequence. The first crystallization unit includes a first crystallizer and a corresponding liquid-solid separation device; the second crystallization unit includes a second crystallizer and a corresponding liquid-solid separation device; and the third crystallization unit includes a third crystallizer and a corresponding liquid-solid separation device. The bottom outlet of the distillation column is connected to the inlet of the first crystallizer; the solid phase outlet of the liquid-solid separation device of the first crystallization unit is connected to the inlet of the second crystallizer; and the solid phase outlet of the liquid-solid separation device of the second crystallization unit is connected to the inlet of the third crystallizer.

[0019] Compared with existing technologies, the beneficial effects of the method for enriching polycyclic aromatic hydrocarbons from oil products, the method for extracting refined anthracene from oil products, and the separation system provided by this invention are as follows:

[0020] Compared to methods using distillation, this invention employs a combination of distillation and crystallization to enrich polycyclic aromatic hydrocarbons (PAHs) from oil products, yielding crude anthracene. This reduces energy consumption during the separation and purification process. Furthermore, the crude anthracene can be used as an intermediate feedstock for further separation of refined anthracene, or as a dye.

[0021] The method provided by this invention enriches, separates and purifies polycyclic aromatic hydrocarbons in oil products through distillation-cooling crystallization. The distillation section can remove most irrelevant impurities, and melt crystallization further removes multi-component impurities with large melting point differences. The selection of crystallization conditions such as solvents in solution crystallization can be precisely controlled to remove key impurities, and finally, refined anthracene products are obtained.

[0022] The method provided by this invention allows for the recycling and reuse of the remaining fractions or mother liquor from each process step, or their return to the raw materials for product extraction, or their return to the oil for other exports, and may even facilitate further hydrogenation and catalytic cracking reactions. Theoretically, there is no waste emission.

[0023] The method provided by this invention is low-carbon, efficient, reasonable, and feasible. It expands the production raw materials for polycyclic aromatic hydrocarbons and reduces raw material costs. At the same time, it provides an export for heavy oil light products such as catalytic cracking light diesel, catalytic primary cycle oil, and catalytic recycle oil, which have good economic and social benefits and promising prospects for promotion. Attached Figure Description

[0024] Figure 1 This is a schematic flowchart of the method for extracting refined anthracene from hydrocarbon oils provided by the present invention.

[0025] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof. Detailed Implementation

[0026] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0027] In a first aspect, the present invention provides a method for enriching polycyclic aromatic hydrocarbons from petroleum products, comprising:

[0028] S1. The catalytic cycle oil is distilled and split in a distillation column to obtain a tricyclic aromatic hydrocarbon-rich fraction with a distillation range of 310–365℃.

[0029] S2. The tricyclic aromatic hydrocarbon-rich fraction is added to the first crystallizer for cooling and crystallization to obtain the first crystal slurry;

[0030] S3. The first crystal slurry is subjected to solid-liquid separation to obtain the first crystal rich in polycyclic aromatic hydrocarbons and the first mother liquor.

[0031] The first crystal is a crude anthracene product enriched with polycyclic aromatic hydrocarbons, which can be used to extract anthracene, phenanthrene, etc., and can also be used to produce anthraquinone dyes, carbon black, synthetic tanning agents and various paints.

[0032] In one embodiment of the present invention, a tricyclic aromatic hydrocarbon-rich fraction with a distillation range of 310–365°C is obtained at the bottom of a distillation column. The distillation range of the tricyclic aromatic hydrocarbon-rich fraction can be any temperature range between two endpoints of 310°C–365°C, including 350°C. For example, the distillation range of the cut tricyclic aromatic hydrocarbon-rich fraction can be 310°C–345°C, 320°C–365°C, or 330°C–350°C. Preferably, the distillation range of the tricyclic aromatic hydrocarbon-rich fraction is in the range of 330°C–350°C.

[0033] The distillation column has a theoretical plate number of 10–90, preferably 30–60; and a reflux ratio of 0.5–10, preferably 2–5. The distillation operation conditions can be atmospheric or vacuum distillation; this invention does not limit this.

[0034] In the method provided by this invention, the catalytic cycle oil has a distillation range of 180℃-370℃, including but not limited to petroleum products such as catalytic cracking light diesel oil, catalytic intermediate cycle oil, and catalytic recycle oil, wherein the tricyclic aromatic hydrocarbon content is greater than 2wt%.

[0035] In the method provided by this invention, the operating conditions of the first crystallizer are as follows: the tricyclic aromatic hydrocarbon fraction is cooled from above room temperature to -30 to 15°C, preferably, the final crystallization temperature is -10 to 10°C; the isothermal time at the final temperature is 0.5 to 10 hours, preferably 1 to 6 hours. This invention employs a slow, uniform cooling method, with a cooling rate of 0.01 to 5°C / h, preferably 3.5 to 5°C / h.

[0036] In a second aspect, the present invention provides a method for extracting refined anthracene from oil products, wherein the above-described method for enriching polycyclic aromatic hydrocarbons (PAHs) from oil products is used to obtain a first crystal rich in PAHs; further comprising:

[0037] S4. The first crystal is mixed with the first solvent and then crystallized in the second crystallizer to obtain the second crystal slurry. After solid-liquid separation, the second crystal and the second mother liquor rich in phenanthrene are obtained. After washing and drying, the second crystal is obtained as crude anthracene crystal.

[0038] S5. The secondary crystals are mixed with the second solvent and then crystallized in the third crystallizer to obtain the third crystal slurry. The third crystal slurry is separated into a third crystal and a third mother liquor. The third crystal is washed and dried to obtain a refined anthracene product with a purity greater than 95%.

[0039] The crystallization processes in the second and third crystallizers are either cooling crystallization or isothermal suspension crystallization. Cooling crystallization refers to the process where the solution system changes from a high-temperature dissolved state to a crystal slurry state through a cooling process, accompanied by crystal nucleation and growth. Isothermal suspension crystallization refers to the crystal slurry undergoing a crystallization-dissolution equilibrium process at an isothermal temperature.

[0040] Preferably, the first mother liquor is returned to the distillation column for recycling, and the second and third mother liquors are returned to the distillation column for recycling after solvent removal in the solvent recovery column.

[0041] The first solvent is selected from one or more of alcohols, ketones, ethers, aromatics, esters and amides; preferably, the first solvent is selected from one or more of ethanol, cyclohexanone, dimethylformamide, methyl tert-butyl ether, toluene, xylene and ethyl acetate; more preferably, toluene, cyclohexanone or dimethylformamide.

[0042] The second solvent is selected from one or more of alcohols, ketones, ethers, aromatics, esters and amides; preferably, the second solvent is selected from one or more of ethanol, cyclohexanone, dimethylformamide, methyl tert-butyl ether, toluene, xylene and ethyl acetate; more preferably, toluene, xylene or cyclohexanone.

[0043] In the method provided by this invention, the operating temperature of the second crystallizer is 20–110°C, preferably 30–60°C; the isothermal time is 0.5–10 h, preferably 2–6 h. The mass ratio of the first crystal to the first solvent is 1:0.2–7, preferably 1–1.4:1; the operating temperature for mixing the first crystal and the first solvent is 20–100°C.

[0044] In the method provided by this invention, the operating temperature of the third crystallizer is 20–110°C, preferably 30–60°C, and the isothermal time is 0.5–10 h, preferably 2–6 h. The mass ratio of the secondary crystal to the second solvent is 1:0.2–10, preferably 0.8–2:1; the operating temperature for mixing the secondary crystal and the second solvent is 20–110°C.

[0045] Specifically, when using cooling crystallization, the temperature of the material in the crystallizer is slowly reduced from 80–150°C to 20–110°C, preferably 30–60°C, and held at the final temperature for 0.5–10 hours, preferably 2–6 hours. The cooling rate can be 0.6–120°C / min, preferably 10–30°C / min. When using suspension isothermal crystallization, the operating temperature is 20–110°C, preferably 30–60°C; the isothermal stirring and suspension time is 0.5–10 hours, preferably 2–6 hours.

[0046] Because the raw materials have a complex system and multiple components are prone to forming eutectic compounds with the target product, the cooling endpoint is much lower than the product's melting point. This helps to enrich the target product while ensuring the enrichment yield and improving the extraction efficiency.

[0047] In the method provided by this invention, the content of tricyclic aromatic hydrocarbons in the catalytic cycle oil is not less than 2%; the tricyclic aromatic hydrocarbon content in the fraction rich in tricyclic aromatic hydrocarbons obtained after distillation and one-step crystallization is 45-80 wt%. The purified anthracene product obtained after two further crystallizations has a purity of at least 95 wt%. The analytical methods for the composition are all based on the industry standard "Determination of Hydrocarbon Composition in Gasoline - Multidimensional Gas Chromatography" (NB / SH / T 0741-2010).

[0048] Thirdly, the present invention provides a separation system for extracting refined anthracene from oil products, comprising a distillation column, a first crystallization unit, a second crystallization unit, and a third crystallization unit connected in sequence. The first crystallization unit includes a first crystallizer and a corresponding liquid-solid separation device; the second crystallization unit includes a second crystallizer and a corresponding liquid-solid separation device; and the third crystallization unit includes a third crystallizer and a corresponding liquid-solid separation device. The bottom outlet of the distillation column is connected to the inlet of the first crystallizer; the solid phase outlet of the liquid-solid separation device of the first crystallization unit is connected to the inlet of the second crystallizer; and the solid phase outlet of the liquid-solid separation device of the second crystallization unit is connected to the inlet of the third crystallizer.

[0049] The present invention will be described in detail below through embodiments. In the embodiments:

[0050] Dimethylformamide, toluene, and cyclohexanone are commercially available products.

[0051] The analytical method for tricyclic aromatic hydrocarbon content in hydrocarbon oils refers to the industry standard "Determination of Hydrocarbon Composition in Gasoline by Multidimensional Gas Chromatography" (NB / SH / T 0741-2010).

[0052] The anthracene content analysis method refers to the industry standard "Determination of Anthracene Content in Industrial Anthracene" (YB / T5086-2014).

[0053] Example 1

[0054] Yangzi coking diesel (distillation range 180–350℃, tricyclic aromatic hydrocarbon content 3.9 wt%) was fractionated in a distillation column. The distillation column was operated under atmospheric pressure, with 35 theoretical plates and a reflux ratio of 3.5. A tricyclic aromatic hydrocarbon-rich fraction with a temperature range of 335–350℃ and a tricyclic aromatic hydrocarbon content >50 wt% was obtained.

[0055] 200g of tricyclic aromatic hydrocarbon-rich fraction was cooled and crystallized in a first crystallizer at a rate of 4℃ / hour from room temperature to a crystallization temperature of 5℃ for 5 hours. After reaching the crystallization endpoint, the solid and liquid phases were separated by filtration to obtain the first crystal and the first mother liquor. The first crystal was washed with ethanol and dried to obtain crude anthracene, in which the anthracene content was 41wt%.

[0056] Crude anthracene was mixed with dimethylformamide at a mass ratio of 1:1 and then fed into a second crystallizer. The mixture was stirred at 80°C for 5 hours and then slowly cooled to 30°C at a cooling rate of 10°C / hour. The mixture was then kept at a constant temperature and stirred for 2 hours. After filtration, the second crystal and the second mother liquor were obtained. The second crystal was washed with ethanol and dried by forced air to obtain secondary crystals. The anthracene content was greater than 80 wt%.

[0057] The secondary crystals were mixed with xylene at a mass ratio of 2:1 and then fed into the third crystallizer. After stirring at a constant temperature of 35°C for 3 hours, the resulting slurry was filtered to obtain the third crystals and the third mother liquor. The third crystals were washed with ethanol and dried by forced air to obtain the refined anthracene product with an anthracene content of 95 wt%.

[0058] Example 2

[0059] A light diesel feedstock from Yanshan catalytic cracking (with a distillation range of 180–370°C) containing approximately 5% tricyclic aromatics was fractionated by distillation under the following conditions: 55 kPa, 30 theoretical plates, and a reflux ratio of 2.5. The fraction obtained was 310–345°C, containing 48.5 wt% bicyclic aromatics, 27.9 wt% tricyclic aromatics, and 21 wt% alkanes.

[0060] The above-mentioned fraction was purified by suspension melt crystallization. 200g of the fraction was weighed and subjected to cooling crystallization in a jacketed crystallizer with a stirrer. The temperature was lowered from room temperature to the crystallization temperature of -5℃ at a rate of 3.5℃ / h, and the crystallization time was 8 hours after reaching the final temperature. The crystal slurry was centrifuged for solid-liquid separation. The solid phase was washed with ethanol and dried to obtain crude anthracene product, containing 42wt% tricyclic aromatic hydrocarbons.

[0061] Example 3

[0062] The fraction of the circulating oil from Yangzi Catalytic Refinery at 330–350 °C was taken, and the mass percentages of its components were as follows: monocyclic aromatic hydrocarbons 2.4%, bicyclic aromatic hydrocarbons 47.4%, and tricyclic aromatic hydrocarbons 42.3%.

[0063] 200g of the above fraction was weighed and cooled for crystallization in a first crystallizer. The temperature was lowered from room temperature to the crystallization temperature of 5℃ at a rate of 5℃ / hour, and the crystallization time was 4 hours after reaching the crystallization endpoint. The fraction was separated into solid and liquid phases by filtration. After washing and drying the solid phase with cyclohexanone, crude anthracene product with an anthracene content of 44.9wt% was obtained.

[0064] Example 4

[0065] The fraction of the circulating oil from Yangzi Catalytic Refinery at 330–350 °C was taken, and the mass percentages of its components were as follows: monocyclic aromatic hydrocarbons 2.4%, bicyclic aromatic hydrocarbons 47.4%, and tricyclic aromatic hydrocarbons 42.3%.

[0066] 200g of the fraction was weighed and subjected to cooling crystallization in the first crystallizer. The temperature was lowered from room temperature to the crystallization temperature of 0℃ at a rate of 5℃ / hour, and the crystallization time was 5 hours after reaching the crystallization endpoint. The fraction was separated into solid and liquid phases by filtration. The solid phase was washed with dimethylformamide and dried to obtain crude anthracene product with an anthracene content of 52.8wt%.

[0067] Example 5

[0068] The crude anthracene with an anthracene content of 42 wt% obtained in Example 2 was purified.

[0069] Crude anthracene and toluene were mixed in a 1:1 mass ratio and then suspended in a crystallizer for crystallization (operating temperature 30℃). After stirring for 5 hours, a second crystal slurry was obtained. After filtration, a second crystal and a second mother liquor were obtained. The second crystal was washed with toluene to obtain secondary crystals with an anthracene content of 80 wt%.

[0070] The secondary crystals were mixed with toluene at a mass ratio of 2:1 and then suspended in a crystallizer for crystallization (operating temperature 50℃). After stirring for 3 hours, the third crystal slurry was obtained. After filtration, the third crystals and the third mother liquor were obtained. The third crystals were washed with toluene and dried to obtain the refined anthracene product. The mass fraction of anthracene was 95% according to the analysis.

[0071] Example 6:

[0072] The crude anthracene with an anthracene content of approximately 44.9 wt% obtained in Example 3 was purified.

[0073] Crude anthracene and cyclohexanone were mixed in a mass ratio of 4:3 and then placed in a crystallizer for suspension crystallization (operating temperature 30℃). After stirring for 5 hours, the resulting second crystal slurry was filtered to obtain the second crystal and the second mother liquor. The second crystal was washed with cyclohexanone to obtain secondary crystals, in which the mass fraction of anthracene was 75%.

[0074] The secondary crystals were mixed with cyclohexanone at a mass ratio of 0.8:1 and then suspended in a crystallizer for crystallization (operating temperature 50℃). After stirring for 3 hours, the third crystal slurry was obtained. The third crystals and the third crystal slurry were separated by filtration. The third crystals were washed with cyclohexanone and dried to obtain the refined anthracene product, in which the mass fraction of anthracene was 95%.

Claims

1. A method for extracting refined anthracene from hydrocarbon oils, characterized in that, include: S1. The catalytic cycle oil is distilled and cut in the distillation column to obtain a tricyclic aromatic hydrocarbon-rich fraction with a distillation range of 310~365℃. S2. The tricyclic aromatic hydrocarbon-rich fraction is added to the first crystallizer for cooling and crystallization to obtain the first crystal slurry; S3. The first crystal slurry is separated into solid and liquid components to obtain a first crystal rich in polycyclic aromatic hydrocarbons and a first mother liquor. In the first crystallizer, the tricyclic aromatic hydrocarbon-rich fraction is cooled from above room temperature to -30~15℃ and kept at a constant temperature to the final temperature for 0.5~10 h. S4. The first crystal is mixed with the first solvent and then crystallized in the second crystallizer to obtain the second crystal slurry. After solid-liquid separation, the second crystal and the second mother liquor rich in phenanthrene are obtained. The second crystal is washed and dried to obtain the secondary crystal. The crystallization temperature of the second crystallizer is 30℃-60℃, and the constant temperature time is 0.5~10 h. The first solvent is selected from one or more of toluene, cyclohexanone and dimethylformamide. S5. The secondary crystals are mixed with the second solvent and then crystallized in the third crystallizer to obtain the third crystal slurry. The third crystal slurry is separated into a third crystal and a third mother liquor. The third crystal is washed and dried to obtain the refined anthracene product. The crystallization temperature of the third crystallizer is 30℃-60℃ and the constant temperature time is 0.5~10 h. The second solvent is selected from one or more of toluene, xylene and cyclohexanone.

2. The method for extracting refined anthracene from hydrocarbon oil according to claim 1, characterized in that, In step S1, a tricyclic aromatic hydrocarbon-rich fraction is obtained at the bottom of the distillation column. The theoretical number of trays in the distillation column is 10 to 90, and the reflux ratio at the top of the column is 0.5 to 10.

3. The method for extracting refined anthracene from hydrocarbon oil according to claim 2, characterized in that, The distillation range of the tricyclic aromatic hydrocarbon-rich fraction is in the range of 330~350℃; the theoretical number of trays of the distillation column is 30~60; and the reflux ratio at the top of the column is 2~5.

4. The method for extracting refined anthracene from hydrocarbon oil according to claim 1, 2 or 3, characterized in that, In the first crystallizer, the tricyclic aromatic hydrocarbon-rich fraction is cooled from above room temperature to -10 to 10°C, and the isothermal time to the final temperature is 1 to 6 hours.

5. The method for extracting refined anthracene from hydrocarbon oils according to claim 1, 2, or 3, characterized in that, The catalytic cycle oil has a distillation range of 180℃-370℃ and contains more than 2wt% tricyclic aromatic hydrocarbons.

6. The method for extracting refined anthracene from hydrocarbon oil according to claim 1, characterized in that, The first mother liquor is returned to the distillation column, and the second and third mother liquors are returned to the distillation column after solvent removal in the solvent recovery column.

7. The method for extracting refined anthracene from hydrocarbon oil according to claim 1 or 6, characterized in that, The crystallization temperature of the second crystallizer is 30℃, and the constant temperature time is 2~6h.

8. The method for extracting refined anthracene from hydrocarbon oil according to claim 1 or 6, characterized in that, The crystallization temperature of the third crystallizer is 50℃, and the constant temperature time is 2~6 h.

9. The method for extracting refined anthracene from hydrocarbon oil according to claim 6, characterized in that, The mass ratio of the first crystal to the first solvent is 1:0.2~7; the mass ratio of the secondary crystal to the second solvent is 1:0.2~10.

10. The method for extracting refined anthracene from hydrocarbon oil according to claim 9, characterized in that, The mass ratio of the first crystal to the first solvent is 1~1.4:1; the mass ratio of the secondary crystal to the second solvent is 0.8~2:1.

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