Process for extracting low-phenanthrene oil from coal tar anthracene oil fraction

Abstract

The invention relates to the technical field of low-phenanthrene oil extraction, in particular to a process for extracting low-phenanthrene oil from coal tar anthracene oil fractions, which comprises the following steps: S1, raw material pretreatment: selecting coal tar anthracene oil fractions as raw materials, and pretreating the coal tar anthracene oil fractions for later use; s2, preparing a solvent, wherein the raw materials of the solvent are selected from heavy alkylbenzene, cyclohexanone, isopropanol, 2-methyltetrahydrofuran and aluminum chloride. According to the invention, the aluminum hydroxide powder can generate a mesoporous material with a porous structure, the sesbania powder is used as a binder in the mesoporous material, so that the aluminum hydroxide powder is in a granular state, and the granular material is soaked in a dilute nitric acid solution, so that an activation effect can be achieved, and the adsorption performance of the treating agent on a nitrogen-containing heterocyclic compound is enhanced; adsorption and impurity removal can be further carried out through bauxite powder treatment before crystallization treatment, so that impurity removal treatment on the anthracene oil fractions of the coal tar is relatively thorough in the pretreatment process, and the extraction efficiency of the anthracene oil is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of low-phenanthrene anthracene oil extraction technology, specifically a process for extracting low-phenanthrene anthracene oil from coal tar anthracene oil fractions. Background Technology

[0002] Low-phenanthrene anthracene oil is a fraction obtained during coal tar distillation and is an intermediate product of coal tar processing. Its main components include polycyclic aromatic hydrocarbons such as phenanthrene, anthracene, and fluorene, and it also contains small amounts of phenols, pyridine bases, and other substances.

[0003] In existing technologies, the extraction processes for low-phenanthrene anthracene oils do not thoroughly remove various impurities during raw material processing, resulting in poor final product yields and affecting the extraction efficiency of low-phenanthrene anthracene oils. Therefore, this invention provides a process for extracting low-phenanthrene anthracene oils from coal tar anthracene oil fractions. Summary of the Invention

[0004] The purpose of this invention is to provide a process for extracting low-phenanthrene anthracene oil from coal tar anthracene oil fraction. The low-phenanthrene anthracene oil prepared by this process not only has good yield performance but also excellent low-phenanthrene properties.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A process for extracting low-phenanthrene anthracene oil from coal tar anthracene oil fraction includes the following steps:

[0007] S1: Raw material pretreatment. The raw material is selected as coal tar anthracene oil fraction. The coal tar anthracene oil fraction is pretreated and ready for use.

[0008] S2: Solvent preparation, the raw materials for which are selected are heavy alkylbenzene, cyclohexanone, isopropanol, 2-methyltetrahydrofuran, and aluminum chloride;

[0009] S3: Mixing process: The pretreated coal tar anthracene oil fraction and solvent are mixed to obtain the base material, which is ready for use.

[0010] S4: Crystallization treatment, the base material is crystallized to obtain low-phenanthrene anthracene oil.

[0011] Further, the method for pretreatment of the raw materials is as follows: coal tar anthracene oil fraction is added to a reaction vessel, the reaction vessel is heated to 50-60°C and kept at that temperature for 2-4 hours, then a treatment agent is added to the reaction vessel, the reaction vessel is set to a temperature of 55-65°C, the stirring speed is 200-400 r / min, and the mixture is stirred at a constant temperature for 1-2 hours. The resulting product is filtered to remove the adsorbent, and the resulting product is distilled at a temperature of 280-300°C to complete the raw material pretreatment. The mass of the treatment agent is 15-25% of the mass of the coal tar anthracene oil fraction.

[0012] Further, the treatment agent is prepared by the following method: aluminum hydroxide powder, deionized water, guar gum powder, and silica sol are added to a mixer, which is set to 400-600 r / min and stirred for 20-40 min. The resulting product is fed into a screw extruder, and the extruded product is slit to obtain granules. The granules are then fed into an oven, which is set to 60-80℃ for drying for 4-6 h, followed by heating to 100-120℃ for drying for 1-2 h. The resulting product is then added to a tube furnace, which is purged with nitrogen gas. The flow rate is 0.5–1 L / min, the heating rate is 4–6 °C / min, the temperature is raised to 300–340 °C, and held for 40–60 min. Then the heating rate is set to 2–4 °C / min, the temperature is raised to 500–540 °C, and held for 2–3 h. The resulting product is immersed in dilute nitric acid solution and activated by stirring in a water bath at 60–70 °C for 2–4 h. The resulting product is rinsed with deionized water and then placed in an oven at 90–110 °C for 3–5 h to obtain the treatment agent.

[0013] Furthermore, the particle size of the aluminum hydroxide powder is 10–30 μm, the mass ratio of aluminum hydroxide powder, deionized water, guar gum powder, and silica sol is 1:(1.3–1.5):(0.04–0.06):(0.08–0.1), and the mass concentration of the dilute nitric acid solution is 8–10%.

[0014] Further, the solvent preparation method is as follows: heavy alkylbenzene, cyclohexanone, isopropanol, 2-methyltetrahydrofuran, and aluminum chloride are added to a mixer, and the mixer is set to 400-600 r / min and stirred for 40-60 min to obtain the solvent.

[0015] Furthermore, the mass ratio of heavy alkylbenzene, cyclohexanone, isopropanol, 2-methyltetrahydrofuran, and aluminum chloride is 1:(0.4-0.6):(0.1-0.2):(0.03-0.05):(0.02-0.04).

[0016] Further, the mixing process is as follows: the pretreated coal tar anthracene oil fraction and solvent are added to a reaction vessel, the reaction vessel is set to a temperature of 60-80°C, the stirring speed is 60-100 r / min, and the mixture is stirred at a constant temperature for 20-40 min to complete the mixing process and obtain the base material.

[0017] Further, the crystallization process is as follows: the base material and bauxite powder are added to a mixer, which is set to 200-400 r / min and stirred for 10-20 min. After that, the bauxite powder is removed by filtration. The resulting product is heated to 60-80℃ and held for 2-4 h. Then, the cooling rate is set to 2-4℃ / h and the temperature is lowered to 44-46℃. The temperature is held for 40-60 min. Then, the cooling rate is set to 1-3℃ / h and the temperature is lowered to 20-25℃. The temperature is held for 2-4 h. The resulting product is cooled to 15-20℃ and filtered under vacuum using a filter cloth to obtain a filter cake. The filter cake is sent to an oven and dried at 50-60℃ for 4-6 h. After that, a melting process is performed to complete the crystallization process and obtain low-phenanthrene anthracene oil.

[0018] Furthermore, the filter cloth has a pore size of 5–10 μm and a vacuum degree of -0.08 MPa.

[0019] Furthermore, the mass of the solvent is 2 to 3 times the mass of the coal tar anthracene oil fraction.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] 1. In this invention, during the extraction of low-phenanthrene anthracene oil, the coal tar anthracene oil fraction is pretreated with a treatment agent. Aluminum hydroxide powder is the main material in the treatment agent. After high-temperature treatment, the aluminum hydroxide powder generates a mesoporous material with a porous structure. Guar sesame powder acts as a binder, causing the aluminum hydroxide powder to form granules. Soaking the granules in dilute nitric acid solution activates the agent and enhances its adsorption performance on nitrogen-containing heterocyclic compounds. Further adsorption and impurity removal are achieved through bauxite powder treatment before crystallization. Therefore, the impurity removal of the coal tar anthracene oil fraction is more thorough during pretreatment, effectively improving the extraction efficiency of anthracene oil.

[0022] 2. In this invention, 2-methyltetrahydrofuran, as an ether solvent, has good solubility for polycyclic aromatic hydrocarbons due to the ether bonds in its molecular structure. At the same time, it can be highly miscible with other components in the solvent. For the anthracene component in the anthracene oil fraction of coal tar, the anthracene component can be enhanced by interacting with its aromatic ring through van der Waals forces, thereby improving the solubility and extraction efficiency. Attached Figure Description

[0023] Figure 1 The present invention provides a flowchart of a process for extracting low-phenanthrene anthracene oil from coal tar anthracene oil fraction. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] It should be noted that the raw materials used in the following embodiments are all commercially available.

[0026] Example 1:

[0027] S1: Raw material pretreatment. The raw material is selected as coal tar anthracene oil fraction. The coal tar anthracene oil fraction is pretreated and ready for use.

[0028] The raw material pretreatment method is as follows: coal tar anthracene oil fraction is added to a reactor, the reactor is set to be heated to 50℃ and kept at that temperature for 2 hours, then a treatment agent is added to the reactor, the reactor is set to be heated to 55℃, the stirring speed is 200 r / min, and the mixture is stirred at a constant temperature for 1 hour. The resulting product is filtered to remove the adsorbent, and the resulting product is distilled at a temperature of 280℃ to complete the raw material pretreatment. The mass of the treatment agent is 15% of the mass of the coal tar anthracene oil fraction.

[0029] The treatment agent was prepared by the following method: aluminum hydroxide powder, deionized water, guar gum powder, and silica sol were added to a mixer and stirred at 400 rpm for 20 minutes. The resulting product was fed into a screw extruder, and the extruded product was slit to obtain granules. The granules were then placed in an oven and dried at 60°C for 4 hours, followed by drying at 100°C for 1 hour. The resulting product was then added to a tube furnace, which was purged with nitrogen at a flow rate of 0.5 L / min and a heating rate of 4°C / min, until the temperature reached 300°C. The temperature was set at ℃ and held for 40 min. Then, the heating rate was set at 2℃ / min, and the temperature was increased to 500℃. The temperature was held for 2 h. The resulting product was immersed in dilute nitric acid solution and activated by stirring in a water bath at 60℃ for 2 h. The resulting product was rinsed with deionized water and then placed in an oven at 90℃ for 3 h to obtain the treatment agent. The particle size of the aluminum hydroxide powder was 10 μm. The mass ratio of aluminum hydroxide powder, deionized water, guar gum powder, and silica sol was 1:1.3:0.04:0.08, and the mass concentration of the dilute nitric acid solution was 8%.

[0030] S2: Solvent preparation. The raw materials for the solvent are heavy alkylbenzene, cyclohexanone, isopropanol, 2-methyltetrahydrofuran, and aluminum chloride. The mass of the solvent is twice the mass of the coal tar anthracene oil fraction.

[0031] The solvent preparation method is as follows: heavy alkylbenzene, cyclohexanone, isopropanol, 2-methyltetrahydrofuran, and aluminum chloride are added to a mixer, and the mixer is set to 400 r / min and stirred for 40 min to obtain the solvent. The mass ratio of heavy alkylbenzene, cyclohexanone, isopropanol, 2-methyltetrahydrofuran, and aluminum chloride is 1:0.4:0.1:0.03:0.02.

[0032] S3: Mixing process: The pretreated coal tar anthracene oil fraction and solvent are mixed to obtain the base material, which is ready for use.

[0033] The mixing process is as follows: the pretreated coal tar anthracene oil fraction and solvent are added to a reaction vessel, the reaction vessel is set to a temperature of 60℃, the stirring speed is 60r / min, and the mixture is stirred at a constant temperature for 20min to complete the mixing process and obtain the base material.

[0034] S4: Crystallization treatment, the base material is crystallized to obtain low-phenanthrene anthracene oil;

[0035] The crystallization process is as follows: the base material and bauxite powder are added to a mixer, which is set to 200 r / min and stirred for 10 min. After that, the bauxite powder is removed by filtration. The resulting product is heated to 60℃ and held for 2 h. Then, the cooling rate is set to 2℃ / h and the temperature is lowered to 44℃ and held for 40 min. After that, the cooling rate is set to 1℃ / h and the temperature is lowered to 20℃ and held for 2 h. The resulting product is cooled to 15℃ and filtered under vacuum using a filter cloth to obtain a filter cake. The filter cake is sent to an oven and dried at 50℃ for 4 h. After that, a melting process is performed to complete the crystallization process and obtain low-phenanthrene anthracene oil. The filter cloth has a pore size of 5 μm and a vacuum degree of -0.08 MPa.

[0036] Example 2:

[0037] S1: Raw material pretreatment. The raw material is selected as coal tar anthracene oil fraction. The coal tar anthracene oil fraction is pretreated and ready for use.

[0038] The raw material pretreatment method is as follows: coal tar anthracene oil fraction is added to a reactor, the reactor is heated to 55℃ and kept at that temperature for 3 hours, then a treatment agent is added to the reactor, the reactor temperature is set to 60℃, the stirring speed is 300 r / min, and the mixture is stirred at a constant temperature for 1.5 hours. The resulting product is filtered to remove the adsorbent, and the resulting product is distilled at a temperature of 290℃ to complete the raw material pretreatment. The mass of the treatment agent is 20% of the mass of the coal tar anthracene oil fraction.

[0039] The treatment agent was prepared by the following method: aluminum hydroxide powder, deionized water, guar gum powder, and silica sol were added to a mixer and stirred at 500 rpm for 30 minutes. The resulting product was fed into a screw extruder, and the extruded product was slit to obtain granules. The granules were then placed in an oven and dried at 70°C for 5 hours, followed by drying at 110°C for 1.5 hours. The resulting product was then added to a tube furnace, which was purged with nitrogen at a flow rate of 0.7 L / min and a heating rate of 5°C / min, until the temperature reached 320°C. The temperature was set at ℃ and held for 50 min. Then, the heating rate was set at 3℃ / min, and the temperature was raised to 520℃. The temperature was held for 2.5 h. The resulting product was immersed in dilute nitric acid solution and stirred and activated in a water bath at 65℃ for 3 h. The resulting product was rinsed with deionized water and then placed in an oven at 100℃ for 4 h to obtain the treatment agent. The particle size of the aluminum hydroxide powder was 20 μm. The mass ratio of aluminum hydroxide powder, deionized water, guar gum powder, and silica sol was 1:1.4:0.05:0.09, and the mass concentration of the dilute nitric acid solution was 9%.

[0040] S2: Solvent preparation. The raw materials for the solvent are heavy alkylbenzene, cyclohexanone, isopropanol, 2-methyltetrahydrofuran, and aluminum chloride. The mass of the solvent is 2.5 times the mass of the coal tar anthracene oil fraction.

[0041] The solvent preparation method is as follows: heavy alkylbenzene, cyclohexanone, isopropanol, 2-methyltetrahydrofuran, and aluminum chloride are added to a mixer, and the mixer is set to 500 r / min and stirred for 50 min to obtain the solvent. The mass ratio of heavy alkylbenzene, cyclohexanone, isopropanol, 2-methyltetrahydrofuran, and aluminum chloride is 1:0.5:0.15:0.04:0.03.

[0042] S3: Mixing process: The pretreated coal tar anthracene oil fraction and solvent are mixed to obtain the base material, which is ready for use.

[0043] The mixing process is as follows: the pretreated coal tar anthracene oil fraction and solvent are added to a reaction vessel, the reaction vessel is set to a temperature of 70℃, the stirring speed is 80r / min, and the mixture is stirred at a constant temperature for 30min to complete the mixing process and obtain the base material.

[0044] S4: Crystallization treatment, the base material is crystallized to obtain low-phenanthrene anthracene oil;

[0045] The crystallization process is as follows: the base material and bauxite powder are added to a mixer, which is set to 300 r / min and stirred for 15 min. After that, the bauxite powder is removed by filtration. The resulting product is heated to 70℃ and held for 3 h. Then, the cooling rate is set to 3℃ / h and the temperature is lowered to 45℃. The temperature is held for 50 min. Then, the cooling rate is set to 2℃ / h and the temperature is lowered to 22℃. The temperature is held for 3 h. The resulting product is cooled to 17℃ and filtered under vacuum using a filter cloth to obtain a filter cake. The filter cake is sent to an oven and dried at 55℃ for 5 h. After that, a melting process is performed to complete the crystallization process and obtain low-phenanthrene anthracene oil. The filter cloth has a pore size of 7 μm and a vacuum degree of -0.08 MPa.

[0046] Example 3:

[0047] S1: Raw material pretreatment. The raw material is selected as coal tar anthracene oil fraction. The coal tar anthracene oil fraction is pretreated and ready for use.

[0048] The raw material pretreatment method is as follows: coal tar anthracene oil fraction is added to a reactor, the reactor is heated to 60℃ and kept at that temperature for 4 hours, then a treatment agent is added to the reactor, the reactor temperature is set to 65℃, the stirring speed is 400 r / min, and the mixture is stirred at a constant temperature for 2 hours. The resulting product is filtered to remove the adsorbent, and the resulting product is distilled at a temperature of 300℃ to complete the raw material pretreatment. The mass of the treatment agent is 25% of the mass of the coal tar anthracene oil fraction.

[0049] The treatment agent was prepared by the following method: aluminum hydroxide powder, deionized water, guar gum powder, and silica sol were added to a mixer and stirred at 600 rpm for 40 minutes. The resulting product was fed into a screw extruder, and the extruded product was slit to obtain granules. The granules were then placed in an oven and dried at 80°C for 6 hours, followed by drying at 120°C for 2 hours. The resulting product was then added to a tube furnace, which was purged with nitrogen at a flow rate of 1 L / min and a heating rate of 6°C / min, until the temperature reached 340°C. The temperature was maintained for 60 min, then the heating rate was set to 4℃ / min, the temperature was raised to 540℃, and maintained for 3 h. The resulting product was immersed in dilute nitric acid solution and activated by stirring in a water bath at 70℃ for 4 h. The resulting product was rinsed with deionized water and then placed in an oven at 110℃ for 5 h to dry, thus obtaining the treatment agent. The particle size of the aluminum hydroxide powder was 30 μm, and the mass ratio of aluminum hydroxide powder, deionized water, guar gum powder, and silica sol was 1:1.5:0.06:0.1. The mass concentration of the dilute nitric acid solution was 10%.

[0050] S2: Solvent preparation. The raw materials for the solvent are heavy alkylbenzene, cyclohexanone, isopropanol, 2-methyltetrahydrofuran, and aluminum chloride. The mass of the solvent is three times the mass of the coal tar anthracene oil fraction.

[0051] The solvent preparation method is as follows: heavy alkylbenzene, cyclohexanone, isopropanol, 2-methyltetrahydrofuran, and aluminum chloride are added to a mixer, and the mixer is set to 600 r / min and stirred for 60 min to obtain the solvent. The mass ratio of heavy alkylbenzene, cyclohexanone, isopropanol, 2-methyltetrahydrofuran, and aluminum chloride is 1:0.6:0.2:0.05:0.04.

[0052] S3: Mixing process: The pretreated coal tar anthracene oil fraction and solvent are mixed to obtain the base material, which is ready for use.

[0053] The mixing process is as follows: the pretreated coal tar anthracene oil fraction and solvent are added to a reaction vessel, the reaction vessel is set to a temperature of 80℃, the stirring speed is 100r / min, and the mixture is stirred at a constant temperature for 40min to complete the mixing process and obtain the base material.

[0054] S4: Crystallization treatment, the base material is crystallized to obtain low-phenanthrene anthracene oil;

[0055] The crystallization process is as follows: the base material and bauxite powder are added to a mixer, which is set to 400 r / min and stirred for 20 min. After that, the bauxite powder is removed by filtration. The resulting product is heated to 80℃ and held for 4 h. Then, the cooling rate is set to 4℃ / h and the temperature is lowered to 46℃. The temperature is held for 60 min. Then, the cooling rate is set to 3℃ / h and the temperature is lowered to 25℃. The temperature is held for 4 h. The resulting product is cooled to 20℃ and filtered under vacuum using a filter cloth to obtain a filter cake. The filter cake is sent to an oven and dried at 60℃ for 6 h. After that, a melting process is performed to complete the crystallization process and obtain low-phenanthrene anthracene oil. The filter cloth has a pore size of 10 μm and a vacuum degree of -0.08 MPa.

[0056] Comparative Example 1: The difference between this comparative example and Example 1 is that no bauxite powder was added during the crystallization process in this comparative example.

[0057] Comparative Example 2 differs from Example 1 in that the comparative example did not involve soaking in dilute nitric acid solution during the preparation of the treatment agent.

[0058] Comparative Example 3 differs from Example 1 in that it does not contain 2-methyltetrahydrofuran.

[0059] Comparative Example 4 differs from Example 1 in that it does not contain a treatment agent.

[0060] Performance testing: The low-phenanthrene anthracene oils prepared in Examples 1, 2, 3, 1, 2, 3, and 4 were subjected to performance testing. The test data are recorded below:

[0061] Table 1

[0062]

[0063] It is evident that the yield and low-phenanthrene performance of the low-phenanthrene anthracene oils prepared in Comparative Examples 1, 2, 3, and 4 are all lower than those in Examples 1, 2, and 3. This indicates that in the extraction process of low-phenanthrene anthracene oil, the pretreatment of the coal tar anthracene oil fraction with a pretreatment agent, in which aluminum hydroxide powder is the main material, can generate a mesoporous material with a porous structure after high-temperature treatment. Guar sesame powder acts as a binder, causing the aluminum hydroxide powder to form granules. Soaking the granules in dilute nitric acid solution can activate them and enhance the adsorption performance of the pretreatment agent for nitrogen-containing heterocyclic compounds. The bauxite powder treatment before crystallization can further remove impurities through adsorption. Thus, the impurity removal of the coal tar anthracene oil fraction is more thorough during the pretreatment process, effectively improving the extraction efficiency of anthracene oil.

[0064] In solvent processing, 2-methyltetrahydrofuran, as an ether solvent, has good solubility for polycyclic aromatic hydrocarbons due to the ether bonds in its molecular structure. At the same time, it is highly miscible with other components in the solvent. For anthracene components in coal tar anthracene oil fraction, the interaction between the anthracene components and its aromatic rings through van der Waals forces can enhance solubility and improve extraction efficiency.

[0065] By comparing and analyzing the relevant data in the table, it can be seen that the low-phenanthrene anthracene oil prepared by the process of extracting low-phenanthrene anthracene oil from coal tar anthracene oil fraction of the present invention not only has good yield performance, but also excellent low-phenanthrene properties. This indicates that the process for extracting low-phenanthrene anthracene oil from coal tar anthracene oil fraction provided by the present invention has a broader market prospect and is more suitable for promotion.

[0066] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0067] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A process for extracting low-phenanthrene anthracene oil from coal tar anthracene oil fraction, characterized in that: Includes the following steps: S1: Raw material pretreatment. The raw material is selected as coal tar anthracene oil fraction. The coal tar anthracene oil fraction is pretreated and ready for use. S2: Solvent preparation, the raw materials for which are selected are heavy alkylbenzene, cyclohexanone, isopropanol, 2-methyltetrahydrofuran, and aluminum chloride; S3: Mixing process: The pretreated coal tar anthracene oil fraction and solvent are mixed to obtain the base material, which is ready for use. S4: Crystallization treatment, the base material is crystallized to obtain low-phenanthrene anthracene oil.

2. The process for extracting low-phenanthrene anthracene oil from coal tar anthracene oil fraction according to claim 1, characterized in that, The method for pretreatment of the raw materials is as follows: coal tar anthracene oil fraction is added to a reaction vessel, the reaction vessel is heated to 50-60℃ and kept at that temperature for 2-4 hours, then a treatment agent is added to the reaction vessel, the reaction vessel is set to a temperature of 55-65℃, the stirring speed is 200-400 r / min, and the mixture is stirred at a constant temperature for 1-2 hours. The resulting product is filtered to remove the adsorbent, and the resulting product is distilled at a temperature of 280-300℃ to complete the raw material pretreatment. The mass of the treatment agent is 15-25% of the mass of the coal tar anthracene oil fraction.

3. The process for extracting low-phenanthrene anthracene oil from coal tar anthracene oil fraction according to claim 2, characterized in that, The treatment agent is prepared by the following method: aluminum hydroxide powder, deionized water, guar gum powder, and silica sol are added to a mixer, which is set to 400-600 r / min and stirred for 20-40 min. The resulting product is fed into a screw extruder, and the extruded product is slit to obtain granules. The granules are then fed into an oven, which is set to 60-80℃ for 4-6 h, followed by drying at 100-120℃ for 1-2 h. The resulting product is then added to a tube furnace, into which nitrogen gas is introduced. The flow rate is 0.5–1 L / min, the heating rate is 4–6 °C / min, the temperature is raised to 300–340 °C, and held for 40–60 min. Then the heating rate is set to 2–4 °C / min, the temperature is raised to 500–540 °C, and held for 2–3 h. The resulting product is immersed in dilute nitric acid solution and activated by stirring in a water bath at 60–70 °C for 2–4 h. The resulting product is rinsed with deionized water and then placed in an oven at 90–110 °C for 3–5 h to obtain the treatment agent.

4. The process for extracting low-phenanthrene anthracene oil from coal tar anthracene oil fraction according to claim 3, characterized in that, The particle size of aluminum hydroxide powder is 10-30 μm, and the mass ratio of aluminum hydroxide powder, deionized water, guar gum powder, and silica sol is 1:(1.3-1.5):(0.04-0.06):(0.08-0.1). The mass concentration of the dilute nitric acid solution is 8-10%.

5. The process for extracting low-phenanthrene anthracene oil from coal tar anthracene oil fraction according to claim 1, characterized in that, The solvent is prepared by adding heavy alkylbenzene, cyclohexanone, isopropanol, 2-methyltetrahydrofuran, and aluminum chloride into a mixer, which is then stirred at 400-600 r / min for 40-60 min to obtain the solvent.

6. The process for extracting low-phenanthrene anthracene oil from coal tar anthracene oil fraction according to claim 5, characterized in that, The mass ratio of heavy alkylbenzene, cyclohexanone, isopropanol, 2-methyltetrahydrofuran, and aluminum chloride is 1:(0.4-0.6):(0.1-0.2):(0.03-0.05):(0.02-0.04).

7. The process for extracting low-phenanthrene anthracene oil from coal tar anthracene oil fraction according to claim 1, characterized in that, The mixing process is as follows: the pretreated coal tar anthracene oil fraction and solvent are added to a reaction vessel, the reaction vessel is set to a temperature of 60-80°C, the stirring speed is 60-100 r / min, and the mixture is stirred at a constant temperature for 20-40 min to complete the mixing process and obtain the base material.

8. The process for extracting low-phenanthrene anthracene oil from coal tar anthracene oil fraction according to claim 1, characterized in that, The crystallization process is as follows: the base material and bauxite powder are added to a mixer, which is set to 200-400 r / min and stirred for 10-20 min. After that, the bauxite powder is removed by filtration. The resulting product is heated to 60-80℃ and held for 2-4 h. Then, the cooling rate is set to 2-4℃ / h and the temperature is lowered to 44-46℃. The temperature is held for 40-60 min. Then, the cooling rate is set to 1-3℃ / h and the temperature is lowered to 20-25℃. The temperature is held for 2-4 h. The resulting product is cooled to 15-20℃ and filtered under vacuum using a filter cloth to obtain a filter cake. The filter cake is sent to an oven and dried at 50-60℃ for 4-6 h. After that, a melting process is performed to complete the crystallization process and obtain low-phenanthrene anthracene oil.

9. The process for extracting low-phenanthrene anthracene oil from coal tar anthracene oil fraction according to claim 8, characterized in that, The filter cloth has a pore size of 5–10 μm and a vacuum degree of -0.08 MPa.

10. The process for extracting low-phenanthrene anthracene oil from coal tar anthracene oil fraction according to claim 1, characterized in that, The mass of the solvent is 2 to 3 times the mass of the coal tar anthracene oil fraction.

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