Method for producing high-quality oil-based needle coke

Abstract

The invention provides a method for producing high-quality oil-based needle coke, which comprises the following steps: (1) in the presence of hydrogen, catalytic slurry oil and active metal are mixed and enter an active metal impurity removal reaction zone for reaction; (2) carrying out separation treatment on the reacted material obtained in the step (1) to obtain a solid-phase material and a liquid-phase material; and (3) feeding the liquid-phase material obtained in the step (2) into a needle coke production device to obtain a final needle coke product. According to the method, an active metal impurity removal technology and a delayed coking process are combined for producing the oil-based needle coke for the first time, the operation is simple, the process operation conditions can be reduced, and heteroatoms contained in the catalytic slurry oil can be removed with high selectivity, so that high-quality raw materials are provided for the delayed coking process, and the high-quality oil-based needle coke is produced.

Description

Technical Field

[0001] The invention belongs to the technical field of petrochemical industry and relates to a method for producing high-quality oil-based needle coke, in particular to a method for producing high-quality oil-based needle coke using catalytic oil slurry as raw material. Background Art

[0002] As the global energy structure undergoes profound changes, the new energy vehicle and energy storage markets continue to develop rapidly, driving rapid growth in the lithium-ion battery industry. As a key raw material for lithium-ion batteries, the anode material industry is also facing historic development opportunities. Needle coke is a high-quality raw material for the production of lithium-ion battery anode materials, leading to strong demand for high-quality raw materials for needle coke production. As one of the primary raw materials for needle coke production, the properties of catalytic cracking slurry oil are crucial factors affecting the quality of needle coke production.

[0003] As a raw material for needle coke production, the presence of heteroatoms can seriously affect the production and performance of needle coke. Therefore, it is usually required to reduce the heteroatom content of FCC slurry, especially the sulfur content.

[0004] CN113862035A discloses a method for producing high-end needle coke raw materials from catalytic cracking slurry. The process involves membrane material desolidification, vacuum distillation enrichment of the filtrate, and hydrogenation of the intermediate fraction, thereby efficiently removing catalyst dust and metal impurities from the catalytic cracking slurry, deeply desulfurizing it, and retaining the aromatic components. The hydrogenation process conditions are a temperature of 350-380°C, a pressure of 3.5-4.0 MPa, and a space velocity of 0.8-1.0 h / min. -1 The sulfur content of refined oil is ≤0.55wt%, and the aromatic content is ≥60wt%.

[0005] CN103013567A discloses a method for producing needle coke raw material from catalytic cracking slurry. The method removes catalyst powder from the slurry by setting up a protection zone, and then removes most of the sulfur in the catalytic cracking slurry by hydrogenation and refining the slurry, thereby producing qualified needle coke raw material.

[0006] The above-mentioned patents generally adopt conventional hydrogenation methods to treat catalytic cracking oil slurry. The conditions of catalytic cracking oil slurry hydrogenation treatment, such as the selection of hydrogenation catalyst, temperature, pressure, treatment degree, etc., have an important impact on the quality of the produced needle coke. The control requirements for the catalytic cracking oil slurry hydrogenation treatment process are high and the operation is relatively complicated. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention provides a method for producing high-quality oil-based needle coke. This method, for the first time, combines active metal removal technology with a delayed coking process to produce oil-based needle coke. This method is simple to operate, reduces process operating conditions, and highly selectively removes heteroatoms from the catalytic oil slurry, thereby providing high-quality raw materials for the delayed coking process and producing high-quality oil-based needle coke.

[0008] A first aspect of the present invention provides a method for producing high-quality oil-based needle coke, the method comprising the following steps:

[0009] (1) In the presence of hydrogen, the catalytic slurry and active metal are mixed and enter the active metal dedoping reaction zone to react;

[0010] (2) separating the reaction material obtained in step (1) to obtain a solid phase material and a liquid phase material;

[0011] (3) The liquid phase material obtained in step (2) enters the needle coke production device to obtain the final needle coke product.

[0012] Furthermore, in the above-mentioned method for producing high-quality oil-based needle coke, the catalytic slurry in step (1) is slurry discarded from a catalytic cracking unit in a refinery. The catalytic slurry has a sulfur content of 0.20-1.80 wt%, preferably 0.90-1.50 wt%, a nitrogen content of 0.01-0.45 wt%, preferably 0.01-0.15 wt%, an asphaltene content of 0.50-10.0 wt%, preferably 0.50-3.50 wt%, an ash content of 0.01-0.70 wt%, preferably 0.10-0.35 wt%, and a residual carbon content of 3.0-25.0 wt%, preferably 3.0-10.0 wt%.

[0013] Furthermore, in the above-mentioned method for producing high-quality oil-based needle coke, in step (1), the aromatic hydrocarbon content in the catalytic oil slurry is controlled to be 30-68wt%, preferably 55-65wt%; wherein the content of tricyclic and tetracyclic aromatic hydrocarbons is 25-55wt%, preferably 30-50wt%, and further preferably 35-45wt%.

[0014] Furthermore, in the above-mentioned method for producing high-quality oil-based needle coke, the active metal in step (1) is one or more of Li, Na, and K, preferably Na; and the mass ratio of the active metal to the catalytic oil slurry is 0.03-0.13:1, preferably 0.03-0.07:1.

[0015] Furthermore, in the above-mentioned method for producing high-quality oil-based needle coke, an auxiliary agent can also be introduced in step (1), and the specific introduction process is: the auxiliary agent is mixed with the catalytic oil slurry and the active metal and introduced into the active metal demixing reactor for reaction; the auxiliary agent is selected from one or more of dihydrophenanthrene, octahydrophenanthrene, tetradecahydrophenanthrene, tetrahydropyrene, hexahydropyrene and hexahydropyrene, preferably octahydrophenanthrene and / or hexahydropyrene; the molar ratio of the auxiliary agent to the active metal is 0.1-2.0, preferably 0.5-1.5.

[0016] Furthermore, in the above-mentioned method for producing high-quality oil-based needle coke, the active metal de-doping reaction zone in step (1) is provided with at least one active metal de-doping reactor, and the active metal de-doping reactor is one or more of a kettle reactor, a pipeline reactor and an ebullated bed reactor, preferably a kettle reactor and / or a pipeline reactor.

[0017] Furthermore, in the above-mentioned method for producing high-quality oil-based needle coke, the operating conditions of the active metal dedoping reaction zone in step (1) are as follows: reaction temperature is 200-360°C, preferably 280-320°C; reaction pressure is 0.5-2.0 MPa, preferably 0.5-1.0 MPa; hydrogen-to-oil volume ratio is 200-500, preferably 200-300; reaction time is 10-60 min, preferably 15-25 min.

[0018] Furthermore, in the above-mentioned method for producing high-quality oil-based needle coke, the separation treatment in step (2) is a solid-liquid separation treatment, and the solid-liquid separation treatment can adopt any means in the prior art that can achieve solid-liquid separation, such as one or more of centrifugal separation, filtration separation and cyclone separation, preferably centrifugal separation.

[0019] Furthermore, in the above-mentioned method for producing high-quality oil-based needle coke, the liquid phase material obtained by the separation treatment in step (2) can also enter a vacuum tower, and be fractionated to obtain a light fraction, an intermediate fraction and a heavy fraction, and the intermediate fraction enters a delayed coking device as the liquid phase material; the distillation range of the intermediate fraction is controlled to be 300-540°C, preferably 360-520°C; the content of three-ring and four-ring aromatic hydrocarbons is greater than 40wt%, preferably greater than 45wt%; the sulfur content is 0.01-0.30wt%, preferably 0.01-0.10wt%; and the asphaltene content is less than 1.0wt%, preferably less than 0.2wt%.

[0020] Furthermore, in the above-mentioned method for producing high-quality oil-based needle coke, the needle coke production apparatus described in step (3) is provided with a heating furnace, a coking tower, and a fractionating tower. Preferably, at least one heating furnace and two coke towers are provided, and at least one coke tower is always maintained in a reaction stage and at least one coke tower is always maintained in a decoking stage. The liquid phase material obtained in step (2) is heated in the heating furnace and then enters the coke tower. The generated needle coke is deposited at the bottom of the tower, and the generated oil and gas are discharged from the top of the tower to the fractionating tower. After separation, gas, naphtha, diesel, and wax oil are obtained.

[0021] Furthermore, in the above-mentioned method for producing high-quality oil-based needle coke, the outlet temperature of the heating furnace in step (3) adopts variable temperature operation, the temperature range is 430-550°C, preferably 450-530°C, the heating rate is 1-40°C / h, preferably 2-20°C / h; the top pressure of the coke tower is 0.2-2.5MPa, preferably 0.5-2.0MPa, and the reaction period is 15-100h, preferably 25-60h.

[0022] Furthermore, in the above method for producing high-quality oil-based needle coke, the yield of the needle coke product in step (3) is ≮33wt%, preferably ≮35wt%.

[0023] A second aspect of the present invention provides needle coke obtained by the above method.

[0024] Furthermore, in the needle coke, the needle coke particle strength coefficient is greater than 14%, preferably 14-20%; and the sulfur content is ≤ 0.27 wt%, preferably 0.05-0.20 wt%.

[0025] Compared with the prior art, the advantages of the present invention are:

[0026] (1) The method of the present invention utilizes active metal treatment technology to pretreat catalytic oil slurry for the first time, which can remove heteroatoms with high selectivity while retaining tricyclic and tetracyclic aromatic hydrocarbons contained in the catalytic oil slurry as much as possible, thereby avoiding the loss of tricyclic and tetracyclic aromatic hydrocarbons during hydrogenation; then, the catalytic oil slurry treated with active metal treatment technology is used as a raw material to produce needle coke, which can effectively reduce the impurity content in the needle coke and improve the yield and performance of the needle coke.

[0027] (2) The method of the present invention introduces special additives during the active metal treatment process, which can further improve the needle coke yield and the particle strength coefficient of the needle coke product. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The figure is a process flow chart for producing high-quality oil-based needle coke.

[0029] Among them, 1 is catalytic oil slurry; 2 is active metal; 3 is hydrogen; 4 is auxiliary agent; 5 is active metal decontamination reactor; 6 is post-reaction material; 7 is solid-liquid separation device; 8 is solid-phase material; 9 is liquid-phase material; 10 is vacuum tower; 11 is light fraction; 12 is heavy fraction; 13 is middle fraction; 14 is heating furnace; 15 is middle fraction after heating in heating furnace; 16 is coke tower; 17 is coking oil gas; 18 is fractionation tower; 19 is gas; 20 is naphtha; 21 is diesel; 22 is wax oil; 23 is needle coke. DETAILED DESCRIPTION

[0030] The method provided by the present invention is described below with reference to the accompanying drawings.

[0031] Catalytic oil slurry 1, active metal 2, hydrogen 3 and additive 4 are mixed and then enter active metal decontamination reactor 5. The reacted material 6 enters solid-liquid separation device 7 for solid-liquid separation. The separated liquid material 9 enters vacuum tower 10 for fractionation to obtain light fraction 11, heavy fraction 12 and middle fraction 13. The middle fraction 13 enters heating furnace 14 to obtain heated middle fraction 15, which then enters coke tower 16. The generated needle coke 23 is deposited at the bottom of the tower. The generated coking oil gas 17 enters fractionation tower 18 for fractionation to obtain gas 19, naphtha 20, diesel 21 and wax oil 22.

[0032] The effect and the result of the inventive method will be further described below in conjunction with the examples, but the following examples do not constitute a limitation to the inventive method. The endpoints and any values ​​of the disclosed ranges are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be considered as specifically disclosed in this article. The contents in the following examples are all weight percentages unless otherwise specified.

[0033] In this paper, the particle strength coefficient was determined using a fully automatic particle strength tester (model LD-KD3) from Shandong Laind Intelligent Technology Co., Ltd. The measurement was performed using the QBSDYD-001 corporate standard of Shandong Yida New Materials Co., Ltd. The main steps involved weighing 100g of needle coke with a particle size of 3.2mm to 7.0mm onto a sample table. An automatic extrusion test pressure of 20kN and a hold time of 60s were then applied. After the automatic extrusion was completed, the percentage of the sample mass greater than 3.2mm in diameter relative to the total sample mass was calculated as the particle strength coefficient.

[0034] In this paper, sulfur content was measured using a fully automatic sulfur analyzer (WDL-HN900A) from Hebi Huaneng Electronic Technology Co., Ltd., in accordance with the national standard GB / T2286-2017, "Determination of Total Sulfur Content in Coke." The main steps involved weighing approximately 0.5g of sample into the sulfur analyzer and recording the mass. A mixture of approximately 5g of sodium carbonate and 3g of potassium hydroxide was added, and the sample was heated to convert the sulfur into sulfur dioxide, which was then blown out. The airflow velocity was measured, the result recorded, and the sulfur content was calculated.

[0035] In the examples and comparative examples of the present invention, the needle coke yield is calculated as follows: S = W1 / W2, wherein: S is the needle coke yield, wt%; W1 is the mass of the obtained needle coke, g; and W2 is the mass of the coking device feed, g.

[0036] In the examples and comparative examples of the present invention, the raw material used is catalytic oil slurry discharged from a catalytic cracking unit of a refinery, which has a sulfur content of 1.31 wt%, a nitrogen content of 0.09 wt%, an asphaltene content of 1.50 wt%, an ash content of 0.15 wt%, a residual carbon content of 4.68 wt%, and an aromatic hydrocarbon content of 62 wt%, of which the content of tri-ring and tetra-ring aromatic hydrocarbons is 39 wt%.

[0037] Example 1

[0038] Catalytic oil slurry, sodium metal, an additive (octahydrophenanthrene), and hydrogen were mixed and introduced into a tubular reactor. The mass ratio of sodium metal to catalytic oil slurry was 0.03:1, and the molar ratio of additive (octahydrophenanthrene) to sodium metal was 0.5. The operating conditions were as follows: reaction temperature 280°C, hydrogen pressure 1.0 MPa, hydrogen-to-oil volume ratio 200, and reaction time 16 minutes.

[0039] After the reaction, the material enters a centrifuge for separation at a speed of 3000 rpm for 10 minutes, yielding solid and liquid phases. The liquid phase enters a vacuum tower for fractional distillation to yield a light fraction, a middle fraction, and a heavy fraction. The middle fraction has a distillation range of 380-500°C and contains 46% by weight of tri- and tetra-ring aromatics, 0.10% by weight of sulfur, and 0.32% by weight of asphaltene.

[0040] The intermediate fraction enters the needle coke production unit, where it is heated in a heating furnace before entering the coke drum. The coking furnace outlet temperature is 450-490°C, with a heating rate of 5°C / hour. The coke drum operates at a constant pressure of 0.7 MPa at the top, and the reaction cycle is 25 hours. The needle coke yield is 35.1% by weight, with a particle strength coefficient of 16.2% and a sulfur content of 0.19% by weight.

[0041] Example 2

[0042] Catalytic oil slurry, sodium metal, an additive (octahydrophenanthrene), and hydrogen were mixed and introduced into a tubular reactor. The mass ratio of sodium metal to catalytic oil slurry was 0.05:1, and the molar ratio of the additive (octahydrophenanthrene) to sodium metal was 0.9. Operating conditions were as follows: reaction temperature 300°C, hydrogen pressure 1.5 MPa, hydrogen-to-oil volume ratio 250, and reaction time 20 minutes.

[0043] After the reaction, the material was centrifuged at 4000 rpm for 10 minutes to separate solid and liquid phases. The liquid phase then entered a vacuum tower for fractional distillation to yield a light fraction, a middle fraction, and a heavy fraction. The middle fraction had a distillation range of 385-490°C and contained 49% by weight of tri- and tetra-ring aromatics, 0.07% by weight of sulfur, and 0.20% by weight of asphaltene.

[0044] The intermediate fraction enters the needle coke production unit. After heating in a heating furnace, it enters the coke drum. The coking furnace outlet temperature is 460-500°C, with a heating rate of 10°C / hour. The coke drum operates at a constant pressure of 1.3 MPa at the top, and the reaction cycle is 40 hours. The needle coke yield is 36.5% by weight, with a particle strength coefficient of 16.8% and a sulfur content of 0.16% by weight.

[0045] Example 3

[0046] Catalytic oil slurry, sodium metal, an additive (hexahydropyrene), and hydrogen were introduced into a tubular reactor. The mass ratio of sodium metal to catalytic oil slurry was 0.07:1, and the molar ratio of the additive (hexahydropyrene) to sodium metal was 1.3. Operating conditions were as follows: reaction temperature 320°C, hydrogen pressure 2.0 MPa, hydrogen-to-oil volume ratio 300, and reaction time 25 minutes.

[0047] After the reaction, the material was centrifuged at 4000 rpm for 15 minutes to separate solid and liquid phases. The liquid phase then entered a vacuum tower for fractional distillation to yield a light fraction, a middle fraction, and a heavy fraction. The middle fraction had a distillation range of 390-485°C and contained 52% by weight of tri- and tetra-ring aromatics, 0.05% by weight of sulfur, and 0.11% by weight of asphaltene.

[0048] The intermediate fraction enters the needle coke production unit. After heating in a heating furnace, it enters the coke drum. The coking furnace outlet temperature is 480-520°C, with a heating rate of 20°C / h. The coke drum operates at a constant pressure of 2.0 MPa at the top, and the reaction cycle is 60 hours. The needle coke yield is 38.2% by weight, with a particle strength coefficient of 17.6% and a sulfur content of 0.12% by weight.

[0049] Example 4

[0050] Catalytic oil slurry, sodium metal, and hydrogen were fed into a tubular reactor at a mass ratio of 0.05:1. Operating conditions included a reaction temperature of 300°C, a hydrogen pressure of 1.5 MPa, a hydrogen-to-oil volume ratio of 300, and a reaction time of 20 minutes.

[0051] After the reaction, the material was centrifuged at 4000 rpm for 10 minutes to separate solid and liquid phases. The liquid phase then entered a vacuum tower for fractional distillation to yield a light fraction, a middle fraction, and a heavy fraction. The middle fraction had a distillation range of 385-490°C and contained 41% by weight of tri- and tetra-ring aromatics, 0.15% by weight of sulfur, and 0.26% by weight of asphaltene.

[0052] The intermediate fraction enters the needle coke production unit. After heating in a heating furnace, it enters the coke drum. The coking furnace outlet temperature is 450-500°C, with a heating rate of 15°C / hour. The coke drum operates at a constant pressure of 1.3 MPa at the top, and the reaction cycle is 40 hours. The needle coke yield is 34.2% by weight, with a particle strength coefficient of 14.4% and a sulfur content of 0.19% by weight.

[0053] Example 5

[0054] Catalytic oil slurry, sodium metal, and hydrogen were fed into a tubular reactor at a mass ratio of 0.07:1. Operating conditions included a reaction temperature of 320°C, a hydrogen pressure of 2.0 MPa, a hydrogen-to-oil volume ratio of 300, and a reaction time of 25 minutes.

[0055] After the reaction, the materials were centrifuged at 4000 rpm for 15 minutes to separate solid and liquid phases. The liquid phase was then fractionated into a vacuum tower to produce a light fraction, a middle fraction, and a heavy fraction. The middle fraction had a distillation range of 390-485°C and contained 44% by weight of tri- and tetra-ring aromatics, 0.10% by weight of sulfur, and 0.14% by weight of asphaltene.

[0056] The intermediate fraction enters the needle coke production unit. After heating in a heating furnace, it enters the coke drum. The coking furnace outlet temperature is 490-530°C, with a heating rate of 25°C / h. The coke drum operates at a constant pressure of 2.0 MPa at the top, and the reaction cycle is 60 hours. The needle coke yield is 34.8% by weight, with a particle strength coefficient of 15.1% and a sulfur content of 0.16% by weight.

[0057] Example 6

[0058] Catalytic oil slurry, sodium metal, an additive (octahydrophenanthrene), and hydrogen were mixed and introduced into a tubular reactor. The mass ratio of sodium metal to catalytic oil slurry was 0.05:1, and the molar ratio of the additive (octahydrophenanthrene) to sodium metal was 0.9. Operating conditions were as follows: reaction temperature 300°C, hydrogen pressure 1.5 MPa, hydrogen-to-oil volume ratio 250, and reaction time 20 minutes.

[0059] After the reaction, the material enters the centrifuge for separation treatment at a centrifugal speed of 4000 r / min and a centrifugal time of 10 min to obtain solid phase material and liquid phase material.

[0060] The liquid phase enters the needle coke production unit, where it is heated in a heating furnace and then enters the coke drum. The coking furnace outlet temperature is 460-500°C, with a heating rate of 10°C / hour. The coke drum operates at a constant pressure of 1.3 MPa at the top, and the reaction cycle is 40 hours. The needle coke yield is 34.9% by weight, with a particle strength coefficient of 14.9% and a sulfur content of 0.17% by weight.

[0061] Comparative Example 1

[0062] After desolidification, the catalytic oil slurry is mixed with hydrogen and fed into a fixed-bed hydrogenation reactor. The reactor is loaded with FZC-33BT catalyst from Sinopec (Dalian) Petrochemical Research Institute Co., Ltd. Operating conditions are as follows: reaction temperature 380°C, hydrogen pressure 10.0 MPa, hydrogen-to-oil volume ratio 500, and space velocity 0.7 h / min. -1 .

[0063] The liquid effluent from the fixed-bed reactor enters a vacuum tower and undergoes fractional distillation to obtain a light fraction, a middle fraction, and a heavy fraction. The middle fraction has a distillation range of 380-495°C and contains 34% by weight of tri- and tetra-ring aromatics, 0.17% by weight of sulfur, and 0.2% by weight of asphaltene.

[0064] The intermediate fraction enters the needle coke production unit. After heating in a heating furnace, it enters the coke drum. The coking furnace outlet temperature is 460-510°C, with a heating rate of 20°C / hour. The coke drum operates at a constant pressure of 1.3 MPa at the top, and the reaction cycle is 40 hours. The needle coke yield is 29.2% by weight, with a particle strength coefficient of 11.5% and a sulfur content of 0.29% by weight.

Claims

1. A method for producing high-quality oil-based needle coke, characterized by: The method includes the following: (1) In the presence of hydrogen, the catalytic slurry and active metal are mixed and enter the active metal dedoping reaction zone to react; (2) separating the reaction material obtained in step (1) to obtain a solid phase material and a liquid phase material; (3) The liquid phase material obtained in step (2) enters the needle coke production device to obtain the final needle coke product.

2. The method according to claim 1, wherein: The sulfur content of the catalytic slurry in step (1) is 0.20-1.80wt%, preferably 0.90-1.50wt%; the nitrogen content is 0.01-0.45wt%, preferably 0.01-0.15wt%; The asphaltene content is 0.50-10.0wt%, preferably 0.50-3.50wt%; the ash content is 0.01-0.70wt%, preferably 0.10-0.35wt%; and the residual carbon content is 3.0-25.0wt%, preferably 3.0-10.0wt%.

3. The method according to claim 1, wherein: In step (1), the aromatic hydrocarbon content in the catalytic oil slurry is controlled to be 30-68wt%, preferably 55-65wt%; wherein the content of tricyclic and tetracyclic aromatic hydrocarbons is 25-55wt%, preferably 30-50wt%, and more preferably 35-45wt%.

4. The method according to claim 1, wherein: The active metal in step (1) is one or more of Li, Na, and K, preferably Na; the mass ratio of the active metal to the catalytic oil slurry is 0.03-0.13:1, preferably 0.03-0.07:

1.

5. The method according to claim 1, wherein: In step (1), an auxiliary agent is also introduced, and the specific introduction process is as follows: the auxiliary agent is mixed with the catalytic slurry and the active metal and introduced into the active metal demixing reactor for reaction; the auxiliary agent is selected from one or more of dihydrophenanthrene, octahydrophenanthrene, tetradecahydrophenanthrene, tetrahydropyrene, hexahydropyrene and hexahydropyrene, preferably octahydrophenanthrene and / or hexahydropyrene; the molar ratio of the auxiliary agent to the active metal is 0.1-2.0, preferably 0.5-1.

5.

6. The method according to claim 1, wherein: The active metal demixing reaction zone in step (1) is provided with at least one active metal demixing reactor, and the active metal demixing reactor is one or more of a kettle reactor, a pipeline reactor and an ebullating bed reactor, preferably a kettle reactor and / or a pipeline reactor.

7. The method according to claim 1, wherein: The operating conditions of the active metal dedoping reaction zone in step (1) are as follows: reaction temperature is 200-360°C, preferably 280-320°C; reaction pressure is 0.5-2.0 MPa, preferably 0.5-1.0 MPa; hydrogen-to-oil volume ratio is 200-500, preferably 200-300; reaction time is 10-60 min, preferably 15-25 min.

8. The method according to claim 1, wherein: The separation treatment in step (2) is a solid-liquid separation treatment, and the solid-liquid separation treatment adopts one or more of centrifugal separation, filtration separation and cyclone separation, preferably centrifugal separation.

9. The method according to claim 1, wherein: The liquid phase material obtained by the separation treatment in step (2) is further fed into a vacuum tower and fractionated to obtain a light fraction, a middle fraction and a heavy fraction. The middle fraction is fed into a delayed coking device as a liquid phase material; the distillation range of the middle fraction is controlled to be 300-540° C., preferably 360-520° C.; the content of tricyclic and tetracyclic aromatic hydrocarbons is greater than 40wt%, preferably greater than 45wt%; and the sulfur content is 0.01-0.30wt%, preferably 0.01-0.10wt%; Asphaltene content <1.0 wt%, preferably <0.2 wt%.

10. The method according to claim 1, wherein: The needle coke production device in step (3) is provided with a heating furnace, a coking tower and a fractionating tower, preferably at least one heating furnace and two coke towers, and at least one coke tower is always kept in the reaction stage and at least one coke tower is always kept in the decoking stage.

11. The method according to claim 1, wherein: The outlet temperature of the heating furnace in step (3) is variable temperature operation, the temperature range is 430-550°C, preferably 450-530°C, the heating rate is 1-40°C / h, preferably 2-20°C / h; the coke tower top pressure is 0.2-2.5MPa, preferably 0.5-2.0MPa, and the reaction period is 15-100h, preferably 25-60h.

12. The method according to claim 1, wherein: The yield of the needle coke product in step (3) is ≮33wt%, preferably ≮35wt%.

13. Needle coke obtained by the method according to any one of claims 1 to 12.

14. The needle coke according to claim 13, wherein: The needle coke particle strength coefficient is greater than 14%, preferably 14-20%; the sulfur content is less than or equal to 0.27 wt%, preferably 0.05-0.20 wt%.

Images