A production method for improving the strength of needle coke particles

Abstract

This invention discloses a production method for improving the strength of needle coke particles. The method includes the following steps: (1) high-sulfur raw material A is hydrogenated to obtain hydrogenated distillate oil; (2) the hydrogenated distillate oil is heated in a heating furnace and then introduced into a coking tower for coking; (3) after the coking process in step (2) continues for a period of time, the coking tower is switched to low-sulfur raw material B for coking; (4) after the coking of low-sulfur raw material B is completed, a wax oil coking process is carried out; (5) after the wax oil coking process is completed, a decoking process is carried out; wherein, the sulfur content of the high-sulfur raw material A is higher than 1.0%, preferably higher than 0.8%, and more preferably 0.5-0.8%; the sulfur content of the low-sulfur raw material B is lower than 0.5%, preferably lower than 0.4%, and more preferably lower than 0.3%. The needle coke prepared by the method has the advantages of high particle strength and low coefficient of thermal expansion.

Description

Technical Field

[0001] This invention belongs to the field of needle coke production and relates to a production method for improving the particle strength of needle coke, specifically a method for producing high particle strength needle coke using petroleum-based or coal-based raw materials. Background Technology

[0002] Needle coke is a solid carbon material with a metallic luster. Under a polarizing microscope, it exhibits a distinct needle-like texture. Due to its high mechanical strength, high true density, and low coefficient of thermal expansion, it is widely used in high-performance graphite electrode materials, lithium-ion batteries, electrochemical capacitors, and other fields.

[0003] US5286371 discloses a hydrotreating process for straight-run residue oil, with a hydrotreating reaction temperature of 379-480℃ and a reaction pressure of 6.8MPa-34.4MPa. The treated heavy residue oil is mixed with catalytic cracking clarified oil and fed into a solvent deasphalting unit. The stream after deasphalting is used as feedstock for needle coke.

[0004] CN202010439340.X discloses a method for preparing needle coke for ultra-high power electrodes from heavy oil. The method uses heavy oil as raw material and employs a size exclusion separation method with polystyrene as the separation column packing to separate components with a relative molecular mass distribution of 400-1000. Acidic and basic components are removed by ion exchange chromatography to obtain a neutral raw material. The treated raw material undergoes a two-stage continuous carbonization process to prepare needle coke.

[0005] CN202011305509.9 discloses a method and process system for producing needle coke from heavy oil, comprising: a fractional cutting process, using heavy oil as raw material to cut it into light distillate oil, heavy distillate oil and tailings; a hydrogenation process, wherein the heavy distillate oil is hydrogenated to obtain hydrogenated heavy distillate; a mixing process, wherein the hydrogenated heavy distillate is mixed with the light distillate oil to obtain a mixed oil; and a delayed coking process, wherein the mixed oil is subjected to delayed coking to obtain needle coke.

[0006] CN202011165491.7 discloses a method for preparing needle coke, in which a mixture of feedstock oil containing high aromatic components and light distillate oil is heated by a heating unit, and the heated material enters a coking tower to react and generate oil gas and needle coke.

[0007] US4894144 discloses a method for simultaneously preparing needle coke and high-sulfur petroleum coke. It employs a hydrotreating process to pretreat straight-run heavy oil, and the hydrotreated residue is divided into two parts, which are then coked and calcined to obtain needle coke and high-sulfur petroleum coke, respectively.

[0008] The strength of needle coke particles is one of the important indicators of needle coke performance. There are few reports in the existing technology on how to improve the strength of needle coke particles, and the particle strength of needle coke obtained by existing preparation methods still needs further improvement. Summary of the Invention

[0009] To address the shortcomings of existing technologies, this invention discloses a production method for improving the strength of needle coke particles. The needle coke prepared by this method has advantages such as high particle strength and low coefficient of thermal expansion.

[0010] A method for improving the strength of needle-shaped coke particles, the method comprising the following steps:

[0011] (1) High-sulfur feedstock A is hydrotreated to obtain hydrotreated distillate oil;

[0012] (2) The hydrogenated distillate oil is heated in a heater and then introduced into a coking tower for coking;

[0013] (3) After the coking process in step (2) continues for a period of time, switch to low-sulfur raw material B to continue coking the coke tower;

[0014] (4) After the low-sulfur raw material B is finished with coking, the wax oil coking process is carried out.

[0015] (5) After the wax oil coking process is completed, the coking removal process is carried out;

[0016] Wherein, the high-sulfur raw material A has a sulfur content of more than 1.0%, preferably more than 0.8%, and more preferably 0.5-0.8%; the low-sulfur raw material B has a sulfur content of less than 0.5%, preferably less than 0.4%, and more preferably less than 0.3%.

[0017] In the above method, the low-sulfur raw material B can be selected from raw materials obtained after hydrogenation treatment, or from fresh raw materials obtained without hydrogenation treatment, with the latter being preferred.

[0018] In the above method, the high-sulfur feedstock A is selected from at least one of coal-based feedstocks and petroleum-based feedstocks with high sulfur content, and preferably from at least one of coal tar, coal tar pitch, heavy petroleum oil, ethylene tar, catalytic cracking slurry oil or thermal cracking residue oil.

[0019] In the above method, the low-sulfur feedstock B is selected from at least one of coal-based feedstocks and petroleum-based feedstocks with low sulfur content, and preferably from at least one of coal tar, coal tar pitch, heavy petroleum oil, ethylene tar, catalytic cracking slurry oil or thermal cracking residue oil.

[0020] In the above method, the properties of the high-sulfur raw material A are as follows: solid content is 0-500 μg / g, preferably 0-200 μg / g, and more preferably 0-50 μg / g.

[0021] In the above method, the 5% distillation point temperature of high-sulfur feedstock A is 360℃-430℃, preferably 380℃-430℃, and the 95% distillation point temperature is 460℃-550℃, preferably 490℃-520℃.

[0022] In the above method, the properties of the low-sulfur raw material B are as follows: the 5% distillation point temperature is 350℃-430℃, preferably 360℃-400℃; the 95% distillation point temperature is 430℃-520℃, preferably 450℃-500℃; and the solid content is 0-200μg / g, preferably 0-100μg / g.

[0023] In the above method, the high-sulfur raw material A has a sulfur content that is 0.1-1.5 wt% higher than that of the low-sulfur raw material B, preferably 0.2-1.0 wt%.

[0024] In the above method, the hydrotreating can be any hydrotreating technology suitable for this invention, such as fixed-bed residue hydrotreating technology, suspended-bed residue hydrotreating technology, fluidized-bed residue hydrotreating technology, moving-bed residue hydrotreating technology, etc. Taking the currently mature fixed-bed hydrotreating technology as an example, the hydrotreating catalyst used refers to a single catalyst or a combination catalyst with functions such as hydrodemetallization, hydrodesulfurization, hydrodenitrogenation, and hydrocracking. These catalysts generally use porous refractory inorganic oxides such as alumina as a support, oxides of Group VIB and / or Group VIII metals such as W, Mo, Co, Ni, etc. as active components, and selectively add various other additives such as P, Si, F, B, etc. For example, the CEN, FZC, ZTN, and ZTS series residue hydrotreating catalysts produced by the Catalyst Division of China Petroleum & Chemical Corporation, and the ZTN and ZTS series catalysts produced by the First Fertilizer Plant of Qilu Petrochemical Company belong to this type of catalyst. Currently, in fixed-bed hydrotreating technology, multiple catalysts are often used in combination, including a protective agent, a hydrodemetallization catalyst, a hydrodesulfurization catalyst, and a hydrodenitrogenation catalyst. The loading sequence is generally such that the feedstock oil comes into contact with the protective agent, hydrodemetallization catalyst, hydrodesulfurization catalyst, and hydrodenitrogenation catalyst in sequence. Of course, there are also techniques that mix and load these catalysts. Hydrotreating typically involves multiple reactors to increase processing capacity. Operation is usually carried out at an absolute pressure of 1 MPa-35 MPa, preferably 2 MPa-6 MPa, and a reaction temperature of 250℃-500℃, preferably 250℃-350℃. The liquid hourly space velocity (LHSV) and hydrogen partial pressure (HBP) are selected based on the characteristics of the feedstock, the required conversion rate, and the degree of refining. The LHSV is typically around 0.1 h⁻¹. -1 -5.0h -1 Ideally, it should be 0.15h. -1 -2.0h -1 Within the range, the total hydrogen-to-oil volume ratio is 100-5000, preferably 300-3000.

[0025] In the above method, the 5% distillation point temperature of the hydrotreated distillate oil in step (1) is 350℃-450℃, preferably 370℃-410℃, and the 95% distillation temperature is 450℃-550℃, preferably 480℃-500℃.

[0026] In the above method, the furnace outlet temperature of the heating furnace in step (2) is 400℃-580℃, preferably 450℃-550℃, and more preferably 480℃-520℃;

[0027] In the above method, the charging duration of the hydrogenated distillate oil introduced into the coke tower in step (2) is 4-30h, preferably 6-15h, and the coke tower pressure is 0.1-1.5MPa, preferably 0.3-1.0MPa, and more preferably 0.4-0.8MPa;

[0028] In the above method, the continuous charging time of raw material B to the coke tower in step (3) is 4-30h, preferably 6-15h, and the coke tower pressure is 0.1-1.5MPa, preferably 0.3-1.0MPa, and more preferably 0.4-0.8MPa;

[0029] In the above method, the furnace outlet temperature in step (3) is 5-50°C lower than the furnace outlet temperature in step (2), preferably 5-30°C.

[0030] In the above method, the coking medium for the wax oil in step (4) is coking heavy wax oil and coking light wax oil, respectively. The 5% distillation point temperature of the coking heavy wax oil fraction is 300℃-380℃, preferably 340℃-360℃, and the 95% distillation point temperature is 400℃-520℃, preferably 410℃-460℃. The 5% distillation point temperature of the coking light wax oil fraction is 250℃-350℃, preferably 280℃-320℃, and the 95% distillation point temperature is 350℃-450℃, preferably 380℃-420℃.

[0031] In the above method, during the coking heavy wax oil charging process in step (4), the outlet temperature of the heating furnace is 450℃-550℃, preferably 480℃-530℃; the coking time is 10-24h, preferably 12-18h; and the coke tower pressure is 0.1-1.0MPa, preferably 0.2-0.8MPa, more preferably 0.3-0.6MPa.

[0032] In the above method, during the coking light wax oil charging process in step (4), the outlet temperature of the heating furnace is 450℃-550℃, preferably 480℃-530℃; the charging time is 1-15h, preferably 2-10h; and the coke tower pressure is 0.1-1.0MPa, preferably 0.1-0.3MPa.

[0033] In the above method, the mass ratio of high-sulfur raw material A, low-sulfur raw material B, coking heavy wax oil, and coking light wax oil is 1:0.5-1.5:0.5-6.0:0.1-0.6.

[0034] Compared with the prior art, the production method of the present invention for improving the strength of needle coke particles has the following advantages:

[0035] (1) Through experiments, the inventors discovered that the ideal components of needle coke feedstock are tricyclic and tetracyclic short-chain aromatics. To meet downstream application requirements, low sulfur and nitrogen content is generally required. For feedstocks with high sulfur and nitrogen content, hydrorefining is necessary. However, the hydrorefining process inevitably leads to ring-opening reactions of aromatics, resulting in a significant reduction in the aromatic carbon content of the feedstock and deterioration of the ideal tricyclic and tetracyclic aromatics, resulting in poor performance of the produced needle coke. To address this issue, a common approach is to directly mix some non-hydrogenated feedstock with the hydrotreated feedstock and then pass them together through a coking furnace into the coke tower for coking, thereby reducing the degree of deterioration of the coking feedstock. However, this blending method does not fully consider the differences in temperature requirements for the thermal reaction processes of the hydrotreated and non-hydrogenated feedstocks, thus limiting its ability to improve the strength of the needle coke product. This invention, by feeding hydrotreated and non-hydrogenated feedstocks in stages and setting the furnace outlet temperature differently according to their thermal reaction performance, can significantly improve the strength of the needle coke product.

[0036] (2) The strength of needle coke is also closely related to the medium and operating conditions of the coking process. Especially in the later stage of coking, the main product of needle coke has been solidified and formed. The coking medium continues to react and form coke, resulting in very low strength of petroleum coke. In this invention, coking light wax oil and heavy wax oil are used to carry out the coking process of needle coke. Heavy wax oil coking realizes the solidification and formation of the system. The main function of light wax oil coking is to further provide heat to the solidified needle coke product to improve the product strength, while significantly reducing the generation of low-strength needle coke by the coking medium. Attached Figure Description

[0037] Figure 1 This is a flow chart of a combined process for preparing needle coke according to the present invention, wherein 1 is raw material A, 2 is a hydrotreating unit, 3 is a hydrotreating product pipeline, 4 is a fractionation tower, 5 is a hydrotreating gas product pipeline, 6 is a pipeline for light diesel oil and below, 7 is hydrotreating distillate oil, 8 is raw material B, 9 is a heating furnace, 10 is a coke tower, 11 is a coking product pipeline, 12 is a coking fractionation tower, 13 is coking gas, 14 is coking gasoline, 15 is coking diesel, 16 is coking heavy wax oil, and 17 is coking light wax oil. Detailed Implementation

[0038] The specific embodiments of the present invention will be described in detail below. However, it should be noted that the scope of protection of the present invention is not limited to these specific embodiments, but is determined by the claims in the appendix.

[0039] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In case of conflict, the definitions in this specification shall prevail.

[0040] When this specification uses the prefixes “known to those skilled in the art,” “prior art,” or similar terms to derive materials, substances, methods, steps, apparatus, or components, the objects derived from such prefixes cover those commonly used in the art at the time of this application, but also include those that are not currently commonly used but will become generally recognized in the art as suitable for similar purposes.

[0041] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this specification are based on weight, unless being based on weight would not be in accordance with the common understanding of those skilled in the art.

[0042] In the context of this specification, any two or more embodiments of the present invention can be arbitrarily combined, and the resulting technical solutions are part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0043] According to one embodiment of the present invention, there is no particular limitation on the type of separation tower. Any separation device that can separate the material fed to the separation tower into multiple components according to predetermined requirements can be used. Specifically, distillation towers, flash distillation towers, evaporation towers, or fractionation towers can be used, with fractionation towers being preferred.

[0044] In the context of this invention, including in the embodiments and comparative examples, the coefficient of thermal expansion was determined according to the international standard GB / T3074.4 "Method for Determination of Coefficient of Thermal Expansion (CTE) of Graphite Electrodes", the volatile matter was determined according to the petrochemical standard SH / T0313 "Test Method for Petroleum Coke", the true density was determined according to the international standard GB / T6155 "Method for Determination of True Density of Carbon Materials", the resistivity was determined according to GB24525-2009 "Method for Determination of Resistivity of Carbon Materials", and the streamlined texture of the needle coke appearance was directly evaluated by visual inspection.

[0045] The present invention will be further described in detail below through embodiments and comparative examples, but the present invention is not limited to the following embodiments.

[0046] like Figure 1As shown: Raw material A passes through hydrogenation unit 2, and the hydrogenation product enters hydrogenation fractionation tower 4 via pipeline 3, separating gas, light diesel oil and lower fractions, and hydrogenated distillate oil. The gas and light diesel oil and lower fractions exit the unit via pipelines 5 and 6, respectively. The hydrogenated distillate oil enters coke tower 10 via pipeline 7, heater 9, and four-way valve. Raw material B enters coke tower 10 via pipeline 8, heater 9, and four-way valve. The oil and gas generated from coking enter the coking fractionation tower 12 from the top of the coke tower via pipeline 11, separating coking gas, coking gasoline, coking diesel, and coking wax oil fractions. The coking gas, coking gasoline, and coking diesel fractions exit the unit via pipelines 13, 14, and 15, respectively. The coking heavy wax oil and coking light wax oil enter coke tower 10 via pipelines 16 and 17, heater 9, and four-way valve. The produced needle coke exits the unit from the bottom of the coke tower.

[0047] Example 1

[0048] The properties of feedstock A and feedstock B provided by a refinery are shown in Table 1. The catalyst used in the hydrotreating unit is the CEN, FZC, ZTN, and ZTS series of residue hydrotreating catalysts produced by the Catalyst Division of China Petroleum & Chemical Corporation (Sinopec). Specifically, it includes a protective agent, a demetallization catalyst, a desulfurization catalyst, and a denitrification catalyst. The loading sequence is generally to allow the feedstock to contact the protective agent, hydrodemetallization catalyst, hydrodesulfurization catalyst, and hydronitrification catalyst in sequence. Of course, there are also techniques that mix and load these catalysts. The catalyst loading techniques described above are well-known to those skilled in the art. The hydrotreating process conditions are shown in Table 2.

[0049] Table 1 Properties of Raw Materials

[0050] Analysis Project Raw material A Raw material B <![CDATA[Density g / cm 3 > 1.0652 1.0432 5% distillation temperature, °C 375 380 95% distillation temperature, °C 500 490 Ash content % 0.02 0.01 C%(w) 91.95 89.63 H%(w) 7.30 9.83 S%(w) 0.81 0.32 Nppm 0.21 0.22 Four components % (w) Saturated portion 15.56 22.17 Aromatic components 79.88 75.26 gelatinous 4.21 2.36 Asphalt 0.35 0.21

[0051] Table 2 Hydrogenation Process Conditions

[0052]

[0053]

[0054] Feed A is processed through a hydrotreating unit to obtain hydrotreated distillate oil. The 5% distillation point temperature is 370℃, and the 95% distillation point temperature is 480℃. The hydrotreated distillate oil is then introduced into a coking tower via a heater. The heater outlet temperature is 490℃, and the duration is 18 hours. The coking tower pressure is 0.6 MPa. Feed B is used to charge the coking tower. The heater outlet temperature is 480℃, and the duration is 10 hours. The coking tower pressure is 0.5 MPa. Coking heavy wax oil undergoes a charging process. The 5% distillation point temperature of the heavy wax oil fraction is 350℃, and the 95% distillation point temperature is 480℃. The distillation point temperature was 460℃, the furnace outlet temperature was 500℃, the coking time was 10h, and the coke tower pressure was 0.6MPa. Light coking wax oil continued to be fed, with the 5% distillation point temperature at 300℃ and the 95% distillation point temperature at 400℃. The furnace outlet temperature was 510℃, the feeding time was 4h, and the coke tower pressure was 0.3MPa. The mass ratio of feedstock A, feedstock B, heavy coking wax oil, and light coking wax oil was 1:0.8:2.0:0.5. The properties of the obtained needle coke product are shown in Table 3.

[0055] Comparative Example 1

[0056] The same raw materials and processes as in Example 1 were used, but raw material B was replaced by hydrogenated raw material A to continue feeding the coke tower. The properties of the final needle coke product are shown in Table 3.

[0057] Example 1-1

[0058] The same raw materials and process as in Example 1 were used, but the coking light wax oil was substituted instead of coking heavy wax oil until the reaction was completed.

[0059] Example 2

[0060] Using the same raw materials and processes as in Example 1, raw material A was processed through a hydrogenation unit to obtain hydrogenated distillate oil with a 5% distillation point temperature of 400°C and a 95% distillation point temperature of 500°C. The hydrogenated distillate oil was then introduced into a coking tower via a heater, with the heater outlet temperature at 500°C for 15 hours and the coking tower pressure at 0.7 MPa. Raw material B was used to charge the coking tower, with the heater outlet temperature at 490°C for 10 hours and the coking tower pressure at 0.6 MPa. The heavy wax oil was then used for charging, with the 5% distillation point temperature of the heavy wax oil fraction at... The temperature of the coking furnace was 360℃, the 95% distillation point was 450℃, the furnace outlet temperature was 510℃, the charging time was 12h, and the coking tower pressure was 0.6MPa. Light wax oil was continuously fed, with the light wax oil fraction having a 5% distillation point of 320℃, a 95% distillation point of 420℃, a furnace outlet temperature of 500℃, a charging time of 3h, and a coking tower pressure of 0.2MPa. The mass ratio of feedstock A, feedstock B, heavy wax oil, and light wax oil was 1:1:2.5:0.5. The properties of the obtained needle coke product are shown in Table 3.

[0061] Example 3

[0062] Using the same raw materials and processes as in Example 1, raw material A was processed through a hydrogenation unit to obtain hydrogenated distillate oil with a 5% distillation point temperature of 360°C and a 95% distillation point temperature of 520°C. The hydrogenated distillate oil was then introduced into a coking tower via a heater, with the heater outlet temperature at 520°C for 20 hours and a coking tower pressure of 0.6 MPa. Raw material B was used to charge the coking tower, with the heater outlet temperature at 480°C for 8 hours and a coking tower pressure of 0.7 MPa. Coking heavy wax oil was then used for the charging process, with the 5% distillation point temperature of the heavy wax oil fraction being... The coking temperature was 320℃, the 95% distillation point was 420℃, the furnace outlet temperature was 500℃, the coking time was 15h, and the coke tower pressure was 0.7MPa. Light wax oil was continuously fed, with the light wax oil fraction having a 5% distillation point of 270℃, a 95% distillation point of 390℃, a furnace outlet temperature of 480℃, a feeding time of 5h, and a coke tower pressure of 0.2MPa. The mass ratio of feedstock A, feedstock B, heavy wax oil, and light wax oil was 1:0.7:1.5:0.6. The properties of the obtained needle coke product are shown in Table 3.

[0063] Table 3 Properties of needle coke produced in the examples and comparative examples

[0064] Analysis Project Example 1 Comparative Example 1 Example 1-1 Example 2 Example 3 <![CDATA[Coefficient of thermal expansion, 10 -6 / °C]]> 0.95 1.0 0.98 0.95 0.94 Sulfur content, w% 0.39 0.40 0.4 0.38 0.36 Volatile matter, w% 5.6 6.2 7.8 6.0 5.9 Ash content, w% 0.01 0.01 0.01 0.01 0.01 <![CDATA[True density, g / cm 3 > 2.14 2.13 2.12 2.15 2.14 <![CDATA[Tap density, g / cm 3 > 0.88 0.83 0.85 0.89 0.90 Particle strength coefficient, % 23.5 17.6 21.2 23.2 23.3

Claims

1. A method for improving the strength of needle-shaped coke particles, the method comprising the following steps: (1) High-sulfur feedstock A is hydrotreated to obtain hydrotreated distillate oil; (2) The hydrogenated distillate oil is heated in a heater and then introduced into the coking tower for coking; (3) After the coking process in step (2) has lasted for a period of time, switch to low-sulfur raw material B to continue coking the coke tower; (4) After the low-sulfur raw material B is finished with coking, the wax oil coking process is carried out; (5) After the wax oil coking process is completed, the decoking process is carried out; in, The high-sulfur raw material A has a sulfur content higher than 0.8%; the low-sulfur raw material B has a sulfur content lower than 0.5%. The low-sulfur feedstock B is selected from fresh feedstock obtained without hydrogenation treatment; The outlet temperature of the heating furnace mentioned in step (2) is 400℃-580℃; The outlet temperature of the heating furnace in step (3) is 5-50°C lower than that in step (2).

2. The method according to claim 1, characterized in that: The sulfur content of the low-sulfur raw material B is less than 0.4%.

3. The method according to claim 1, characterized in that: The sulfur content of the low-sulfur raw material B is less than 0.3%.

4. The method according to claim 1, characterized in that: The high-sulfur raw material A is selected from at least one of coal-based raw materials and petroleum-based raw materials with high sulfur content.

5. The method according to claim 4, characterized in that: The high-sulfur feedstock A is selected from at least one of coal tar, coal tar pitch, heavy petroleum oil, ethylene tar, catalytic cracking slurry oil, or thermal cracking residue oil.

6. The method according to claim 1, characterized in that: The low-sulfur raw material B is selected from at least one of coal-based raw materials and petroleum-based raw materials with low sulfur content.

7. The method according to claim 6, characterized in that: The low-sulfur feedstock B is selected from at least one of coal tar, coal tar pitch, heavy petroleum oil, ethylene tar, catalytic cracking slurry oil, or thermal cracking residue oil.

8. The method according to claim 1, characterized in that: The properties of the high-sulfur raw material A are as follows: solid content is 0-500µg / g.

9. The method according to claim 8, characterized in that: The properties of the high-sulfur raw material A are as follows: solid content is 0-200µg / g.

10. The method according to claim 8, characterized in that: The properties of the high-sulfur raw material A are as follows: solid content is 0-50µg / g.

11. The method according to claim 1, characterized in that: The 5% distillation temperature of high-sulfur feedstock A is 360℃-430℃, and the 95% distillation temperature is 460℃-550℃.

12. The method according to claim 11, characterized in that: The 5% distillation temperature of high-sulfur feedstock A is 380℃-430℃, and the 95% distillation temperature is 490℃-520℃.

13. The method according to claim 1, characterized in that: The properties of the low-sulfur feedstock B are as follows: 5% distillation temperature is 350℃-430℃, 95% distillation temperature is 430℃-520℃; solid content is 0-200µg / g.

14. The method according to claim 13, characterized in that: The properties of the low-sulfur feedstock B are as follows: 5% distillation temperature is 360℃-400℃, 95% distillation temperature is 450℃-500℃; solid content is 0-100µg / g.

15. The method according to claim 1, characterized in that: The high-sulfur raw material A has a higher sulfur content than the low-sulfur raw material B by 0.1-1.5 wt%.

16. The method according to claim 15, characterized in that: The high-sulfur raw material A has a higher sulfur content by 0.2-1.0 wt% compared to the low-sulfur raw material B.

17. The method according to claim 1, characterized in that: The hydrogenated distillate oil described in step (1) has a 5% distillation temperature of 350℃-450℃ and a 95% distillation temperature of 450℃-550℃.

18. The method according to claim 17, characterized in that: The hydrogenated distillate oil described in step (1) has a 5% distillation temperature of 370℃-410℃ and a 95% distillation temperature of 480℃-500℃.

19. The method according to claim 1, characterized in that: The outlet temperature of the heating furnace in step (2) is 450℃-550℃.

20. The method according to claim 19, characterized in that: The outlet temperature of the heating furnace in step (2) is 480℃-520℃.

21. The method according to claim 1, characterized in that: The duration of the hydrogenated distillate oil introduced into the coking tower in step (2) is 4-30 hours, and the pressure of the coking tower is 0.1-1.5 MPa.

22. The method according to claim 21, characterized in that: The duration of the hydrogenated distillate oil introduced into the coking tower in step (2) is 6-15 hours, and the pressure of the coking tower is 0.3-1.0 MPa.

23. The method according to claim 21, characterized in that: Step (2), the pressure of the coke tower is 0.4-0.8 MPa.

24. The method according to claim 1, characterized in that: In step (3), the low-sulfur raw material B is continuously fed into the coke tower for 4-30 hours, and the coke tower pressure is 0.1-1.5 MPa.

25. The method according to claim 24, characterized in that: In step (3), the low-sulfur raw material B is continuously fed into the coke tower for 6-15 hours, and the pressure of the coke tower is 0.3-1.0 MPa.

26. The method according to claim 24, characterized in that: Step (3), the pressure of the coke tower is 0.4-0.8 MPa.

27. The method according to claim 1, characterized in that: The outlet temperature of the heating furnace in step (3) is 5-30°C lower than that in step (2).

28. The method according to claim 1, characterized in that: Step (4) The coking media for the wax oil are coking heavy wax oil and coking light wax oil, respectively. The 5% distillation temperature of the coking heavy wax oil is 300℃-380℃, and the 95% distillation temperature is 400℃-520℃. The 5% distillation temperature of the coking light wax oil is 250℃-350℃, and the 95% distillation temperature is 350℃-450℃.

29. The method according to claim 28, characterized in that: The coking media for the wax oil in step (4) are coking heavy wax oil and coking light wax oil, respectively. The 5% distillation temperature of the coking heavy wax oil is 340℃-360℃, and the 95% distillation temperature is 410℃-460℃. The 5% distillation temperature of the coking light wax oil is 250℃-350℃, and the 95% distillation temperature is 380℃-420℃.

30. The method according to claim 28, characterized in that: During the coking process of heavy wax oil, the outlet temperature of the heating furnace is 450℃-550℃; the charging time is 10-24h; and the coke tower pressure is 0.1-1.0MPa.

31. The method according to claim 30, characterized in that: During the coking process of heavy wax oil, the outlet temperature of the heating furnace is 480℃-530℃; the charging time is 12-18h; and the coke tower pressure is 0.2-0.8MPa.

32. The method according to claim 30, characterized in that: During the coking process of heavy wax oil, the pressure in the coke tower is 0.3-0.6 MPa.

33. The method according to claim 28, characterized in that: During the coking process of light wax oil, the outlet temperature of the heating furnace is 450℃-550℃; the charging time is 1-15h; and the coke tower pressure is 0.1-1.0MPa.

34. The method according to claim 33, characterized in that: During the coking process of light wax oil, the outlet temperature of the heating furnace is 480℃-530℃; the charging time is 2-10h; and the coke tower pressure is 0.1-0.3MPa.

35. The method according to claim 28, characterized in that: The mass ratio of high-sulfur feedstock A, low-sulfur feedstock B, heavy coking wax oil, and light coking wax oil is 1:0.5-1.5:0.5-6.0:0.1-0.6.

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