A process for processing and converting medium and low temperature coal tar

Abstract

This application discloses a medium- and low-temperature coal tar processing and conversion process, comprising: feeding medium- and low-temperature coal tar feedstock into a delayed coking unit to obtain needle coke and delayed coking product oil; the delayed coking product oil entering a fractionation tower to separate phenolic oil; the phenolic oil undergoing dephenolization to obtain dephenolized oil; the dephenolized oil entering a hydrorefining section to obtain hydrorefined product oil; the hydrorefined product oil entering a fractionation tower to cut gasoline, diesel, and kerosene fractions; the kerosene fraction entering a hydroisomerization section to obtain hydroisomerized product oil; the hydroisomerized product oil entering a hydroreforming section to obtain hydroreformed product oil; and the hydroreformed product oil entering a fractionation tower to obtain aviation kerosene blank oil. Through the comprehensive utilization of coal tar through deep processing, aviation kerosene and high-value chemicals such as gasoline, diesel, phenolic chemicals, and needle coke are produced, improving the utilization rate of coal tar resources. Simultaneously, the deep processing of coal tar extends into the field of high-value materials, fully realizing the sustainable development of coal tar processing.

Description

Technical Field

[0001] This application relates to the field of coal chemical technology, specifically to a medium- and low-temperature coal tar processing and conversion process. Background Technology

[0002] With the rapid development of the aerospace industry, my country's demand for jet fuel is increasing daily. In 2021, my country's aviation kerosene consumption reached 28.175 million tons, a year-on-year increase of 7.7%. Currently, the main source of jet fuel is refined from crude oil through direct refining and secondary processing, resulting in relatively low production volumes. In recent years, my country's oil imports have been increasing year by year. In 2021, my country's crude oil imports rose to 513 million tons, with an external dependence rate of 72.1%. Moreover, 80% of crude oil imports need to pass through military-sensitive areas such as the Strait of Malacca, seriously affecting my country's energy security.

[0003] The "863" Program project "Preparation Technology of Coal-based High-Density Military Aviation Fuel," undertaken by Shenhua Group, has made breakthrough progress in the research of coal-based jet fuel. The coal-based jet fuel prepared by this project has advantages such as low sulfur and nitrogen content, high specific gravity, high heat capacity, high thermal stability, and high volumetric calorific value, with many indicators superior to petroleum-based aviation fuels. On September 10, 2021, the National Key Research and Development Project "Technology for Special Fuels and Chemicals from Coal Liquefaction and Recombination," undertaken by the Coal Chemical Branch of the China Coal Research Institute, successfully passed the comprehensive performance evaluation meeting of the Ministry of Science and Technology in Beijing. Comparative evaluation with US military standards (JP-8, JP-900), Russian military standards (T-8), and domestic petroleum-based jet fuel (RP-3) showed that the product independently developed by the China Coal Research Institute has the characteristics of high density, high volumetric calorific value, high volumetric specific heat capacity, high thermal stability (heat resistant to 485℃ without decomposition), low sulfur (<1ppm), low nitrogen (<1ppm), low pour point (-70℃), low aromatics (<2%), and corrosion resistance. However, the raw material for both of the above processes is direct coal liquefaction oil.

[0004] Coal tar, a product of coal pyrolysis / dry distillation, is produced in huge quantities annually. Currently, my country mainly uses coal tar as a raw material to produce gasoline and diesel fuel via hydrogenation. However, there are no reported technological routes for producing aviation kerosene from coal tar, and the technology lags behind advanced foreign coal tar hydroconversion technologies for jet fuel production. Summary of the Invention

[0005] To address the aforementioned shortcomings in this field, this application aims to provide a medium- and low-temperature coal tar processing and conversion process. Through a series of technical means such as delayed coking, catalytic hydrorefining, isomerization, modification, and fractionation, coal tar is processed to produce aviation kerosene, with high-value byproducts such as needle coke. This significantly improves the utilization rate of coal tar resources and, compared to traditional coal tar processing for gasoline, diesel, and naphtha production, represents a completely new processing route in the field of deep coal tar processing.

[0006] According to one aspect of this application, a medium-low temperature coal tar processing and conversion process is provided, comprising:

[0007] Medium- and low-temperature coal tar feedstock is fed into a delayed coking unit to obtain needle coke and delayed coking product oil; the reaction temperature of the delayed coking is 300-500℃ and the reaction pressure is 0.2MPa-1MPa.

[0008] The delayed coking product oil is fed into a fractionation tower for fractionation to separate phenolic oil;

[0009] The phenolic oil is subjected to dephenolization to obtain dephenolized oil;

[0010] The dephenolized oil is then fed into a hydrorefining section to obtain a hydrorefined product oil. The hydrorefining reaction temperature is 150-400℃, the pressure is 5-20 MPa, the hydrogen-to-oil volume ratio is 800:1-3000:1, and the liquid hourly space velocity is 0.2-2 h⁻¹. -1 ;

[0011] The hydrotreated product oil is fed into a fractionating tower for fractionation to separate gasoline, diesel and kerosene fractions.

[0012] The kerosene fraction is fed into a hydroisomerization section to obtain hydroisomerized product oil; the hydroisomerization reaction temperature is 200-450℃, the pressure is 2-15MPa, the hydrogen-to-oil volume ratio is 800:1-3000:1, and the liquid hourly space velocity is 0.2-2h. -1 ;

[0013] The hydrotreated isomerized product oil is fed into a hydrotreating section to obtain a hydrotreated product oil. The hydrotreating reaction temperature is 80-300℃, the pressure is 5-20MPa, the hydrogen-to-oil volume ratio is 800:1-3000:1, and the liquid hourly space velocity is 0.2-2h. -1 ;

[0014] The hydrotreated product oil is fed into a fractionation tower to obtain aviation kerosene blank oil;

[0015] The catalyst for hydrorefining uses alumina as a support, with one or more of Ni, Mo, and W as active metals, at a loading of 1%-15%, and a specific surface area of ​​100-300 m². 2 / g, with a length of 3-10mm;

[0016] The catalyst for hydroisomerization uses molecular sieves as a support, with noble metals such as Pt and Pd as active components, a loading of 5-40%, and a specific surface area of ​​150-350 m². 2 / g, length 1.4-2mm;

[0017] The catalyst for hydrogenation reforming uses alumina as a support, with one or more of Ni, Mo, and W as active metals, at a loading of 1%-15%, and a specific surface area of ​​200-400 m². 2 / g, length 1-3mm.

[0018] According to some embodiments of this application, the distillation column is an atmospheric distillation apparatus.

[0019] According to some embodiments of this application, the hydrogen in the hydrorefining, hydroisomerization and hydromodification sections is raw coal gas and pyrolysis gas produced by coal dry distillation and coal pyrolysis.

[0020] According to some embodiments of this application, the S and N contents of the hydrorefined product oil are both less than 2 ppm.

[0021] According to some embodiments of this application, in industrial production, the mechanical impurity content in medium- and low-temperature coal tar is less than 0.55%, and the moisture content is less than 2.5%.

[0022] Compared with the prior art, this application has at least the following beneficial effects:

[0023] This application provides a medium-low temperature coal tar processing and conversion process. Using medium-low temperature coal tar as raw material, the process comprehensively utilizes the deep processing of coal tar to produce aviation kerosene, gasoline, diesel, phenolic chemicals, needle coke, and other high-value chemicals. This greatly improves the utilization rate of coal tar resources and extends the deep processing of coal tar into the field of high-value materials, thus fully realizing the sustainable development of coal tar processing.

[0024] The process route described in this application removes phenolic oil, which can effectively improve the H / C ratio and cleanliness of the hydrogenation feedstock, reduce the hydrogen consumption in subsequent hydrogenation processes, and produce high-value chemicals such as phenol and o-cresol, effectively increasing the added value of coal tar. Attached Figure Description

[0025] Figure 1 This is a flowchart of a medium- and low-temperature coal tar processing and conversion process in an example embodiment of this application. Detailed Implementation

[0026] The technical solution of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] It should be particularly noted that similar substitutions and modifications made to this application are obvious to those skilled in the art, and they are all considered to be included in this application. Those skilled in the art can obviously make modifications or appropriate alterations and combinations to the methods and applications described herein without departing from the content, spirit, and scope of this application to implement and apply the technology of this application. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0028] Unless otherwise specified, this application shall be made in accordance with conventional conditions or conditions recommended by the manufacturer. The raw materials or excipients used, as well as the reagents or instruments used, whose manufacturers are not specified, are all conventional products that can be obtained commercially.

[0029] The following is a detailed description of this application.

[0030] In 2022, my country's coal tar production was approximately 24.62 million tons, with deep processing accounting for about 12.45 million tons. Coal tar contains a relatively large amount of aromatics, cycloalkanes, and phenolic compounds. After denitrification, desulfurization, deoxygenation, and dephenolization of coal tar, it is catalytically hydrogenated. By controlling the depth of hydrogenation, olefins and aromatic compounds can be saturated, resulting in the production of naphtha and diesel oil.

[0031] This application utilizes a series of technical means, including delayed coking, catalytic hydrogenation refining, isomerization, modification, and fractionation, to process coal tar into aviation kerosene and produce high-value byproducts such as needle coke. This significantly improves the utilization rate of coal tar resources. Compared with the traditional coal tar processing for gasoline, diesel, and naphtha production, this application represents a completely new processing route in the field of deep coal tar processing. It not only has positive development significance for alleviating my country's oil resource shortage but also for meeting the demand for special fuels.

[0032] Coal tar contains many mechanical impurities and heavy components. In this application, delayed coking technology is used to solve the problem of lightening coal tar and producing high-value needle coke. At the same time, it removes sulfur, nitrogen and heavy metals, realizing the early cracking and condensation of coal tar, effectively ensuring the cleanliness of subsequent hydrogenation products. Meanwhile, the high reaction temperature of the delayed coking unit can ensure the stability of the product oil aviation kerosene.

[0033] The technological process route of this application is as follows:

[0034] 1. Low-temperature coal tar feedstock enters the delayed coking unit to obtain needle coke and delayed coking product oil.

[0035] In industrial production, the mechanical impurity content of medium- and low-temperature coal tar is less than 0.55%, and the moisture content is less than 2.5%. Excessive mechanical impurity content can lead to pipeline blockage during industrial production; excessive moisture content can cause excessively large temperature fluctuations in the reactor, affecting product quality. The operating conditions for delayed coking are as follows: reaction temperature 300-500℃, reaction pressure 0.2MPa-1MPa.

[0036] 2. Delayed coking product oil enters the fractionation tower to separate the phenolic oil from the oil and send it to the fine powder section for further production of high-value products such as phenol and m-cresol through a dephenolization process.

[0037] The dephenolization process is a solvent extraction method. The specific process is as follows: Phenolic oil is separated from crude phenol and dephenolized oil in the extraction section. The extraction solvent is recycled within the unit, and the crude phenol is sent to the distillation section for further processing. In the refining section, the crude phenol undergoes dehydration, slag removal, and pyridine removal. Then, based on the different volatility of various phenols, it is continuously produced through phenol, o-cresol, and m-cresol distillations to extract crude phenol, o-cresol, and m-cresol fractions, respectively. Finally, through intermittent distillation, finished phenol, o-cresol, and m-cresol products are produced, respectively.

[0038] 3. The dephenolized oil from step 2 enters the hydrorefining section, where catalytic hydrogenation saturates some of the unsaturated hydrocarbons and removes heteroatoms such as S, N, and O from the oil, so that the content of S and N is less than 2 ppm.

[0039] The conditions for the hydrorefining reaction are: 150-400℃, 5-20MPa, hydrogen-to-oil volume ratio of 800:1-3000:1, and liquid hourly space velocity of 0.2-2h. -1 .

[0040] 4. The product oil from step 3 enters the fractionation tower to separate gasoline, diesel and kerosene fractions. Gasoline and diesel fractions can be used as products.

[0041] 5. The kerosene fraction enters the hydroisomerization section, which isomerizes the straight-chain alkanes in the oil, improving the oil's low-temperature fluidity.

[0042] The conditions for the hydroisomerization reaction are: 200-450℃, 2-15MPa, hydrogen-to-oil volume ratio of 800:1-3000:1, and liquid hourly space velocity of 0.2-2h. -1 .

[0043] 6. The product oil from step 5 enters the hydrotreating section for further hydrogenation saturation of unsaturated hydrocarbons such as aromatics and olefins in the oil.

[0044] The conditions for the hydrotreating reaction are: 80-300℃, 5-20MPa, hydrogen-to-oil volume ratio of 800:1-3000:1, and liquid hourly space velocity of 0.2-2h. -1 .

[0045] 7. The product oil from step 6 enters the fractionation tower, cuts the appropriate fraction segment, obtains aviation kerosene blank oil, adds appropriate additives, and then becomes the aviation kerosene product.

[0046] The fractionation process uses conventional atmospheric distillation equipment.

[0047] The hydrogen used in this application is derived from raw coal gas and pyrolysis gas produced by coal dry distillation and coal pyrolysis, and is purified by methods such as pressure swing adsorption.

[0048] The coal tar raw material property analysis data in the embodiments of this application are as follows:

[0049]

[0050]

[0051] Example 1

[0052] The properties of the low-temperature dry distillation coal tar from Shenmu City are shown in Table 1. After being sent to the delayed coking unit, it undergoes cracking and condensation reactions to produce needle coke and coking oil. The reaction temperature is 400℃ and the pressure is 0.25 MPa.

[0053] The coking oil is sent to a fractionation tower to separate the phenolic oil fraction;

[0054] Phenolic oil is sent to the phenol refining unit to produce phenol products with a purity of over 99.5%, o-cresol products with a purity of over 99.5%, and m- and p-cresol products with a purity of over 90%.

[0055] The dephenolized oil is sent to the hydrorefining section for hydrorefining. The hydrorefined oil is then passed through a fractionation tower to obtain gasoline, diesel, and kerosene fractions. The gasoline and diesel fractions are used as products.

[0056] The kerosene fraction is then further processed into aviation kerosene through hydroisomerization and reforming reactions.

[0057] The hydrorefining reaction conditions were: 360℃, 15MPa, hydrogen-to-oil volume ratio of 1200:1, and liquid hourly space velocity of 0.5h⁻¹. -1 The hydroisomerization reaction conditions were: 360℃, 3MPa, hydrogen-to-oil volume ratio of 1000:1, and liquid hourly space velocity of 0.5h⁻¹. -1 The hydrotreating reaction conditions were: 170℃, 3MPa, hydrogen-to-oil volume ratio of 800:1, and liquid hourly space velocity of 0.3h⁻¹. -1 ;

[0058] The hydrorefining catalyst uses alumina as a support, with one or more of Ni, Mo, and W as the active metal, at a loading of 1%-15%, and a specific surface area of ​​100-300 m². 2 / g, with a length of 3-10mm;

[0059] Hydroisomerization catalysts use molecular sieves as supports and noble metals such as Pt and Pd as active components, with a loading of 5-40% and a specific surface area of ​​150-350 m². 2 / g, length 1.4-2mm;

[0060] The hydrotreating catalyst uses alumina as a support, with one or more of Ni, Mo, and W as the active metal, at a loading of 1%-15%, and a specific surface area of ​​200-400 m². 2 / g, length 1-3mm;

[0061] Hydrorefining and modification catalysts undergo routine pre-sulfurization treatment before use.

[0062] Example 2

[0063] The properties of the low-temperature dry distillation coal tar from Shenmu City are shown in Table 1. After being sent to the delayed coking unit, it undergoes cracking and condensation reactions to produce needle coke and coking oil. The reaction temperature is 440℃ and the pressure is 0.35MPa.

[0064] The coking oil is sent to a fractionation tower to separate the phenolic oil fraction. The phenolic oil is then sent to a phenol refining unit to produce phenol products with a purity of over 99.5%, o-cresol products with a purity of over 99.5%, and m-cresol products with a purity of over 90%.

[0065] The dephenolized oil is sent to the hydrorefining section for hydrorefining. The hydrorefined oil is then passed through a fractionation tower to obtain gasoline, diesel, and kerosene fractions. The gasoline and diesel fractions are used as products.

[0066] The kerosene fraction is then further processed into aviation kerosene through hydroisomerization and reforming reactions.

[0067] The hydrorefining reaction conditions were: 350℃, 15MPa, hydrogen-to-oil volume ratio of 1500:1, and liquid hourly space velocity of 0.5h⁻¹. -1 The hydroisomerization reaction conditions were: 350℃, 3MPa, hydrogen-to-oil volume ratio of 1200:1, and liquid hourly space velocity of 0.5h⁻¹. -1 The hydrotreating reaction conditions were: 150℃, 3MPa, hydrogen-to-oil volume ratio of 800:1, and liquid hourly space velocity of 0.3h⁻¹. -1 .

[0068] The hydrorefining catalyst uses alumina as a support, with one or more of Ni, Mo, and W as the active metal, at a loading of 1%-15%, and a specific surface area of ​​100-300 m². 2 / g, with a length of 3-10mm;

[0069] Hydroisomerization catalysts use molecular sieves as supports and noble metals such as Pt and Pd as active components, with a loading of 5-40% and a specific surface area of ​​150-350 m². 2 / g, length 1.4-2mm;

[0070] The hydrotreating catalyst uses alumina as a support, with one or more of Ni, Mo, and W as the active metal, at a loading of 1%-15%, and a specific surface area of ​​200-400 m². 2 / g, length 1-3mm.

[0071] Hydrorefining and modification catalysts undergo routine pre-sulfurization treatment before use.

[0072] Comparative Example 1: Different pressures were applied during the hydrorefining, hydroisomerization, and hydromodification reactions.

[0073] The properties of the low-temperature dry distillation coal tar from Shenmu City are shown in Table 1. After being sent to the delayed coking unit, it undergoes cracking and condensation reactions to produce needle coke and coking oil. The reaction temperature is 440℃ and the pressure is 0.35MPa.

[0074] The coking oil is sent to a fractionation tower to separate the phenolic oil fraction. The phenolic oil is then sent to a phenol refining unit to produce phenol products with a purity of over 99.5%, o-cresol products with a purity of over 99.5%, and m-cresol products with a purity of over 90%.

[0075] The dephenolized oil is sent to the hydrorefining section for hydrorefining. The hydrorefined oil is then passed through a fractionation tower to obtain gasoline, diesel, and kerosene fractions. The gasoline and diesel fractions are used as products.

[0076] The kerosene fraction is then further processed into aviation kerosene through hydroisomerization and reforming reactions.

[0077] The hydrorefining reaction conditions were: 350℃, 15MPa, hydrogen-to-oil volume ratio of 1500:1, and liquid hourly space velocity of 0.5h⁻¹. -1 The hydroisomerization reaction conditions were: 350℃, 5MPa, hydrogen-to-oil volume ratio of 1200:1, and liquid hourly space velocity of 0.5h⁻¹. -1 The hydrotreating reaction conditions were: 150℃, 5MPa, hydrogen-to-oil volume ratio of 800:1, and liquid hourly space velocity of 0.3h⁻¹. -1 .

[0078] The hydrorefining catalyst uses alumina as a support, with one or more of Ni, Mo, and W as the active metal, at a loading of 1%-15%, and a specific surface area of ​​100-300 m². 2 / g, with a length of 3-10mm;

[0079] Hydroisomerization catalysts use molecular sieves as supports and noble metals such as Pt and Pd as active components, with a loading of 5-40% and a specific surface area of ​​150-350 m². 2 / g, length 1.4-2mm;

[0080] The hydrotreating catalyst uses alumina as a support, with one or more of Ni, Mo, and W as the active metal, at a loading of 1%-15%, and a specific surface area of ​​200-400 m². 2 / g, length 1-3mm.

[0081] Hydrorefining and modification catalysts undergo routine pre-sulfurization treatment before use.

[0082] Comparative Example 2: Different types of catalysts

[0083] The properties of the low-temperature dry distillation coal tar from Shenmu City are shown in Table 1. After being sent to the delayed coking unit, it undergoes cracking and condensation reactions to produce needle coke and coking oil. The reaction temperature is 440℃ and the pressure is 0.35MPa.

[0084] The coking oil is sent to a fractionation tower to separate the phenolic oil fraction. The phenolic oil is then sent to a phenol refining unit to produce phenol products with a purity of over 99.5%, o-cresol products with a purity of over 99.5%, and m-cresol products with a purity of over 90%.

[0085] The dephenolized oil is sent to the hydrorefining section for hydrorefining. The hydrorefined oil is then passed through a fractionation tower to obtain gasoline, diesel, and kerosene fractions. The gasoline and diesel fractions are used as products.

[0086] The kerosene fraction is then further processed into aviation kerosene through hydroisomerization and reforming reactions.

[0087] The hydrorefining reaction conditions were: 350℃, 15MPa, hydrogen-to-oil volume ratio of 1500:1, and liquid hourly space velocity of 0.5h⁻¹. -1 The hydroisomerization reaction conditions were: 350℃, 3MPa, hydrogen-to-oil volume ratio of 1200:1, and liquid hourly space velocity of 0.5h⁻¹. -1 The hydrotreating reaction conditions were: 150℃, 3MPa, hydrogen-to-oil volume ratio of 800:1, and liquid hourly space velocity of 0.3h⁻¹. -1 .

[0088] The hydrorefining catalyst uses alumina as a support, with one or more of Ni and Mo as the active metal, at a loading of 5%-15%, and a specific surface area of ​​200-500 m². 2 / g, with a length of 3-10mm;

[0089] Hydroisomerization catalysts use molecular sieves as supports, Pt as the active component, with a loading of 5-15% and a specific surface area of ​​150-350 m². 2 / g, length 1.4-2mm;

[0090] The hydrotreating catalyst uses alumina as a support, Ni as the active metal, with a loading of 3%-10% and a specific surface area of ​​200-400 m². 2 / g, length 1-3mm.

[0091] Hydrorefining and modification catalysts undergo routine pre-sulfurization treatment before use.

[0092] Comparative Example 3: Kerosene fraction cut after hydrorefining without fractionation

[0093] The properties of the low-temperature dry distillation coal tar from Shenmu City are shown in Table 1. After being sent to the delayed coking unit, it undergoes cracking and condensation reactions to produce needle coke and coking oil. The reaction temperature is 440℃ and the pressure is 0.35MPa.

[0094] The coking oil is sent to a fractionation tower to separate the phenolic oil fraction. The phenolic oil is then sent to a phenol refining unit to produce phenol products with a purity of over 99.5%, o-cresol products with a purity of over 99.5%, and m-cresol products with a purity of over 90%.

[0095] The dephenolized oil is sent to the hydrorefining section for hydrorefining reaction. The oil obtained from hydrorefining is then further processed through hydroisomerization and modification reactions to produce aviation kerosene.

[0096] The hydrorefining reaction conditions were: 350℃, 15MPa, hydrogen-to-oil volume ratio of 1500:1, and liquid hourly space velocity of 0.5h⁻¹. -1 The hydroisomerization reaction conditions were: 350℃, 3MPa, hydrogen-to-oil volume ratio of 1200:1, and liquid hourly space velocity of 0.5h⁻¹. -1 The hydrotreating reaction conditions were: 150℃, 3MPa, hydrogen-to-oil volume ratio of 800:1, and liquid hourly space velocity of 0.3h⁻¹. -1 .

[0097] The hydrorefining catalyst uses alumina as a support, with one or more of Ni, Mo, and W as the active metal, at a loading of 1%-15%, and a specific surface area of ​​100-300 m². 2 / g, with a length of 3-10mm;

[0098] Hydroisomerization catalysts use molecular sieves as supports and noble metals such as Pt and Pd as active components, with a loading of 5-40% and a specific surface area of ​​150-350 m². 2 / g, length 1.4-2mm;

[0099] The hydrotreating catalyst uses alumina as a support, with one or more of Ni, Mo, and W as the active metal, at a loading of 1%-15%, and a specific surface area of ​​200-400 m². 2 / g, length 1-3mm.

[0100] Hydrorefining and modification catalysts undergo routine pre-sulfurization treatment before use.

[0101] Experimental Example

[0102] The products were tested according to the requirements of GB 6573-2018, as follows (among which, the product of Comparative Example 3 also met the national standard requirements after fractionation, but the yield of qualified products was less than 45%):

[0103]

[0104]

[0105] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of this application. It should be noted that, for those skilled in the art, several improvements and modifications can be made to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. A process for the conversion of medium-low temperature coal tar characterized in that, include: Medium- and low-temperature coal tar feedstock is fed into a delayed coking unit to obtain needle coke and delayed coking product oil. The delayed coking product oil is fed into a fractionation tower for fractionation to separate phenolic oil; The phenolic oil is subjected to dephenolization to obtain dephenolized oil; The dephenolized oil is then fed into a hydrorefining section to obtain a hydrorefined product oil. The hydrorefining reaction temperature is 150-400℃, the pressure is 5-20 MPa, the hydrogen-to-oil volume ratio is 800:1-3000:1, and the liquid hourly space velocity is 0.2-2 h⁻¹. -1 ; The hydrotreated product oil is fed into a fractionating tower for fractionation to separate gasoline, diesel and kerosene fractions. The kerosene fraction is fed into a hydroisomerization section to obtain hydroisomerized product oil; the hydroisomerization reaction temperature is 200-450℃, the pressure is 2-15MPa, the hydrogen-to-oil volume ratio is 800:1-3000:1, and the liquid hourly space velocity is 0.2-2h. -1 ; The hydrotreated isomerized product oil is fed into a hydrotreating section to obtain a hydrotreated product oil. The hydrotreating reaction temperature is 80-300℃, the pressure is 5-20MPa, the hydrogen-to-oil volume ratio is 800:1-3000:1, and the liquid hourly space velocity is 0.2-2h. -1 ; The hydrotreated product oil is fed into a fractionation tower to obtain aviation kerosene blank oil; The catalyst for hydrorefining uses alumina as a support, and one or more of Ni, Mo, and W are active metals, with the active metal loading being 1%-15%. The catalyst for hydroisomerization uses molecular sieves as a support and Pt and Pd as active components, with the loading of the active components being 5-40%. The catalyst for hydrogenation modification uses alumina as a support, and one or more of Ni, Mo, and W as active metals, with the active metal loading being 1%-15%. wherein the hydrofining catalyst has a specific surface area of 100-300 m 2 / g; The catalyst for hydroisomerization has a specific surface area of ​​150-350 m². 2 / g; The hydro-upgrading catalyst has a specific surface area of 200-400 m 2 / g; The mechanical impurities content of the medium- and low-temperature coal tar feedstock is less than 0.55%, and the moisture content is less than 2.5%. The delayed coking reaction temperature is 300-500℃, and the reaction pressure is 0.2MPa-1MPa.

2. The medium-low temperature coal tar processing conversion process according to claim 1, characterized in that, The distillation tower is an atmospheric distillation unit.

3. The medium-low temperature coal tar processing conversion process according to claim 1, characterized in that, The hydrogen used in the hydrorefining, hydroisomerization, and hydromodification sections is pyrolysis gas produced by coal pyrolysis.

4. The medium-low temperature coal tar processing conversion process according to claim 1, characterized in that, The S and N contents of the hydrorefined product oil are both less than 2 ppm.

5. The medium-low temperature coal tar processing conversion process according to claim 1, characterized in that, The phenol removal process is a solvent extraction method.

6. The medium-low temperature coal tar processing conversion process according to claim 5, characterized by the fact that, The solvent extraction method includes: The crude phenol and the dephenolized oil are separated in the extraction section. The extraction solvent is recycled within the unit, and the crude phenol is sent to the distillation section for further processing. In the refining section, crude phenol is first dehydrated, slag removed, and pyridine removed; after continuous production in phenol, o-cresol, and m-p-cresol towers, crude products of phenol, o-cresol, and m-p-cresol fractions are extracted respectively; finally, after intermittent distillation, finished products of phenol, o-cresol, and m-p-cresol are produced respectively.

7. The medium-low temperature coal tar processing conversion process according to claim 1, characterized in that, The catalyst used for hydrorefining has a length of 3-10 mm; The catalyst for hydroisomerization has a length of 1.4-2 mm; The catalyst length for the hydrogenation modification is 1-3 mm.

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