Method and device for increasing yield of high-quality low-sulfur petroleum coke

Abstract

The invention relates to the technical field of petrochemical engineering, in particular to a method and device for increasing the yield of high-quality low-sulfur petroleum coke. The method comprises the following steps: carrying out hydrodesulfurization pretreatment on raw oil and a catalyst, carrying out heat treatment on an obtained liquid-solid component I, carrying out separation and extraction on an obtained liquid-solid component II, and carrying out coking treatment on an obtained coking raw material to obtain low-sulfur petroleum coke of which the sulfur content is less than or equal to 2wt%, wherein the catalyst is selected from at least one complex formed by bonding an active metal and an organic ligand through a coordinate bond. According to the method provided by the invention, high-efficiency conversion of the raw oil is realized, and the yield of high-quality petroleum coke is increased; meanwhile, the method also widens the raw material of the low-sulfur petroleum coke, and realizes the economic added value of the raw oil, especially the high-sulfur inferior raw oil.

Description

Technical Field

[0001] The present invention relates to the technical field of petrochemical industry, in particular to a method for increasing the production of high-quality low-sulfur petroleum coke and a device for increasing the production of high-quality low-sulfur petroleum coke. Background Art

[0002] Petroleum coke, a solid product obtained from the delayed coking unit of an oil refinery, is an irreplaceable raw material for a variety of industries, including glass, steel, and electrolytic aluminum. The quality of petroleum coke is significantly influenced by the type of crude oil processed by the refinery, as most of the sulfur and impurities in the crude oil are concentrated in the petroleum coke. Petroleum coke is categorized by sulfur content. Low-sulfur petroleum coke with a sulfur content of 3% or less is primarily used in the steel and aluminum industries to make electrodes. High-sulfur coke with a sulfur content exceeding 3% is considered an economical alternative to thermal coal and is primarily used in the cement, power, and steel industries. In most countries around the world, high-sulfur petroleum coke is still primarily used as a fuel for power plants. High-quality, low-sulfur petroleum coke is widely used in the steel, aluminum, and carbon industries, significantly increasing its value.

[0003] As the trend toward heavier petroleum resources intensifies, my country's crude oil imports, particularly high-sulfur crude oil, are gradually increasing, leading to a corresponding increase in the production of high-sulfur petroleum coke. Reducing the sulfur content of coking feedstocks is key to reducing high-sulfur coke production and producing low-sulfur coke. The combined process of residue oil hydrogenation and delayed coking can address the high sulfur content of petroleum coke faced by delayed coking. However, hydrodesulfurization inevitably results in the loss of residual carbon, an effective component in coking. Therefore, achieving coking feedstocks with high residual carbon content while achieving effective desulfurization, thereby meeting the significantly increased demand for low-sulfur coke from downstream industries, is a crucial consideration during process development.

[0004] CN201110353406.4 discloses a combined process for residue hydrotreating and delayed coking. Residue oil, coker gas oil, and hydrogen are mixed and reacted in a hydrotreating unit. The resulting hydrotreated residue oil and vacuum gas oil are then separated and mixed or mixed with other conventional feedstocks and fed into a delayed coking unit. The coking products are then separated, with the coker gas oil being recycled to the residue hydrotreating unit. This method can produce low-sulfur petroleum coke. However, the fixed bed has strict restrictions on the asphaltene and metal content of the feed.

[0005] CN201110322478.2 discloses a combined process for residue hydrotreating and delayed coking. This process utilizes an ebullated-bed hydrotreating process for residue hydrotreating. The process involves directly feeding the liquid product of the residue feedstock after ebullated-bed hydrotreating into a coking fractionator without fractionation. The liquid product then enters countercurrent contact with the coking-generated oil and gas, washing away coke fines carried by the high-temperature oil and gas. The light fractions generated by the hydrogenation are then discharged from the fractionator along with the light fractions generated by the coking process. The fractions above the wax oil are recycled back to the delayed coking unit. This process combines ebullated-bed residue hydrotreating with delayed coking, but the limited domestic industrial application of ebullated-bed residue hydrotreating units limits its widespread application.

[0006] Therefore, the development of a combined residue oil hydrogenation-delayed coking process that can increase the production of high-quality low-sulfur coke is of great significance for solving the outlet of high-sulfur coke, improving resource utilization, and meeting market demand. Summary of the Invention

[0007] The purpose of the present invention is to overcome the above technical problems and provide a method for increasing the production of high-quality low-sulfur petroleum coke and a device for increasing the production of high-quality low-sulfur petroleum coke. The method adopts a specific process to obtain high-quality and high-yield low-sulfur petroleum coke.

[0008] To achieve the above objectives, the present invention provides, in a first aspect, a method for increasing the production of high-quality low-sulfur coke, comprising: subjecting crude oil and a catalyst to a hydrodesulfurization pretreatment, heat-treating the obtained liquid-solid fraction I, separating and extracting the obtained liquid-solid fraction II, and coking the obtained coking feedstock to obtain low-sulfur petroleum coke having a sulfur content of ≤2 wt%;

[0009] Wherein, the catalyst is selected from at least one complex formed by active metal and organic ligand bonded by coordination bonds.

[0010] Preferably, the method comprises the following steps:

[0011] (1) subjecting the feedstock oil and the catalyst to the hydrodesulfurization pretreatment in the presence of hydrogen to obtain the liquid-solid component I and the gas I;

[0012] (2) subjecting the liquid-solid component I to the heat treatment to obtain the liquid-solid component II and the gas II;

[0013] (3) separating and extracting the liquid-solid component II to obtain tail oil, light components, and heavy components;

[0014] (4) using the heavy component as the coking raw material to perform the coking process to obtain the low-sulfur petroleum coke;

[0015] Wherein, the separation and extraction is selected from extraction separation-distillation coupling and distillation cutting.

[0016] A second aspect of the present invention provides a device for increasing the production of high-quality low-sulfur petroleum coke, the device comprising a reaction unit, a heat treatment unit, a separation and extraction unit, and a coking unit connected in sequence;

[0017] The reaction unit is used to perform hydrodesulfurization pretreatment on the raw oil and the catalyst in the presence of hydrogen to obtain gas I and liquid-solid component I; the heat treatment unit is used to perform heat treatment on the liquid-solid component I to obtain gas II and liquid-solid component II; the separation and extraction unit is used to separate and extract the liquid-solid component II to obtain tail oil, light components and heavy components; and the coking unit is used to perform coking treatment on the heavy components as coking raw materials to obtain low-sulfur petroleum coke with a sulfur content of ≤2wt%.

[0018] Through the above technical solution, the method provided by the present invention adopts a process combining hydrodesulfurization pretreatment, heat treatment, separation and extraction, and delayed coking, and combines with a specific catalyst to obtain a coking raw material with a higher residual carbon content while effectively desulfurizing. This method not only achieves efficient conversion of raw oil and increases the production of high-quality petroleum coke; at the same time, the method also broadens the raw materials for low-sulfur petroleum coke and realizes the economic added value of raw oil, especially high-sulfur and low-quality raw oil.

[0019] Furthermore, the method provided by the present invention is also combined with a specific catalyst. In a hydrogen-rich environment, the catalyst has high oil-phase dispersibility and hydrodesulfurization selectivity, and can perform targeted adsorption and desulfurization of sulfur-containing compounds in the feedstock oil, thereby improving the desulfurization effect. In a hydrogen-poor environment, the catalyst also has a dehydrogenation and polycondensation effect, thereby obtaining a coking feedstock with a high residual carbon content. While achieving efficient conversion of high-sulfur, low-quality feedstock oil, it can also increase the production of high-quality, low-sulfur petroleum coke. Therefore, using the low-sulfur petroleum coke provided by the present invention as a negative electrode material opens up a new source of negative electrode plate raw materials while ensuring high electrochemical performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the structure of a device for increasing the production of high-quality low-sulfur petroleum coke provided by the present invention;

[0021] Figure 2 This is a schematic structural diagram of another device for increasing the production of high-quality low-sulfur petroleum coke provided by the present invention;

[0022] Figure 3 is the infrared spectrum of catalyst C1-C2 used in the examples.

[0023] Description of Reference Numerals

[0024] I. Reaction unit; II. Heat treatment unit; III. Separation and extraction unit; III-1. Extraction and separation section; III-2. Distillation section; III-3. Distillation and cutting tower; IV. Coking unit; IV-1. Coking furnace; IV-2. Fractionation tower; 1. Raw oil; 2. Catalyst; 3. Hydrogen; 4. Gas I; 5. Liquid-solid component I; 6. Gas II; 7. Liquid-solid component II; 8. External tail oil; 9. Desolidified oil; 10. Light component; 11. Heavy component; 12. Low-sulfur petroleum coke; 13. Coking gas; 14. Coking naphtha; 15. Coking diesel; 16. Coking wax oil; 17. Gas-liquid mixture. DETAILED DESCRIPTION

[0025] The endpoints of the ranges and any values ​​disclosed herein 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 endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0026] In the present invention, unless otherwise specified, the "top" of a container refers to the position of 0-10% from the top to the bottom of the container; the "upper part" of a container refers to the position of 10-40% from the top to the bottom of the container; the "middle" of a container refers to the position of 40-60% from the top to the bottom of the container; the "lower part" of a container refers to the position of 60-90% from the top to the bottom of the container; and the "bottom" of a container refers to the position of 90-100% from the top to the bottom of the container.

[0027] A first aspect of the present invention provides a method for increasing the production of high-quality low-sulfur coke, the method comprising: subjecting crude oil and a catalyst to hydrodesulfurization pretreatment, heat-treating the obtained liquid-solid component I, separating and extracting the obtained liquid-solid component II, and coking the obtained coking raw material to obtain low-sulfur petroleum coke with a sulfur content of ≤2wt%;

[0028] Wherein, the catalyst is selected from at least one complex formed by active metal and organic ligand bonded by coordination bonds.

[0029] In some embodiments of the present invention, preferably, the method comprises the following steps:

[0030] (1) subjecting the feedstock oil and the catalyst to the hydrodesulfurization pretreatment in the presence of hydrogen to obtain the liquid-solid component I and the gas I;

[0031] (2) subjecting the liquid-solid component I to the heat treatment to obtain the liquid-solid component II and the gas II;

[0032] (3) separating and extracting the liquid-solid component II to obtain tail oil, light components, and heavy components;

[0033] (4) using the heavy component as the coking raw material to perform the coking process to obtain the low-sulfur petroleum coke;

[0034] Wherein, the separation and extraction is selected from extraction separation-distillation coupling and distillation cutting.

[0035] In some embodiments of the present invention, preferably, the raw oil has a sulfur content of ≥3wt%, an asphaltene content of ≥11wt%, a heavy metal content calculated as Ni and / or V of ≥150ppm, and a kinematic viscosity at 100°C of ≥2000mm 2 / s.

[0036] In the present invention, the feedstock oil may be selected from a wide range of types, as long as the above-mentioned limitations are met. Preferably, the feedstock oil is selected from high-sulfur, low-quality oil; more preferably, the feedstock oil is selected from at least one of high-sulfur crude oil, high-sulfur deasphalted oil, and high-sulfur vacuum residue.

[0037] In the present invention, the hydrodesulfurization pretreatment is intended to remove the sulfur content in the feed oil to obtain a liquid-solid component I with a low sulfur content.

[0038] In some embodiments of the present invention, preferably, in step (1), the temperature of the hydrodesulfurization pretreatment is 380-440°C, for example, 380°C, 400°C, 410°C, 420°C, 430°C, 440°C, and any value in the range consisting of any two values, preferably 400-430°C.

[0039] In some embodiments of the present invention, preferably, in step (1), the hydrogen partial pressure of the hydrodesulfurization pretreatment is 8-20 MPa, for example, 8 MPa, 10 MPa, 11 MPa, 12 MPa, 13 MPa, 14 MPa, 15 MPa, 16 MPa, 18 MPa, 20 MPa, and any value in a range consisting of any two values, preferably 10-18 MPa. In the present invention, the hydrogen partial pressure refers to the gauge pressure.

[0040] In some embodiments of the present invention, preferably, in step (1), the volume space velocity of the hydrodesulfurization pretreatment is 0.05-0.6h -1 , for example, 0.05h -1 , 0.1h -1 , 0.2h -1 , 0.3h -1 , 0.4h -1 , 0.5h -1 , 0.6h -1, and any value in the range of any two values, preferably 0.1-0.5h -1 In the present invention, the volume space velocity refers to the volume space velocity of the feed oil.

[0041] In some embodiments of the present invention, preferably, in step (1), the conditions of the hydrodesulfurization pretreatment further include: the concentration of the catalyst calculated as metal element is 200-20000 μg / g, for example, 200 μg / g, 500 μg / g, 1000 μg / g, 2000 μg / g, 5000 μg / g, 8000 μg / g, 10000 μg / g, 15000 μg / g, 20000 μg / g, and any value in the range consisting of any two values, preferably 500-10000 μg / g.

[0042] In some embodiments of the present invention, preferably, in step (1), the hydrodesulfurization pretreatment is carried out in a slurry bed reactor. The gas, liquid, and solid three-phase distribution in a slurry bed reactor is uniform, and the highly dispersed catalyst is suspended in the liquid medium, which can achieve effective contact with the hydrogen and oil phases; heat transfer is uniform, the reaction temperature is uniform, and there are no hot spots in the reactor; no online loading and unloading of agents is required, and the catalyst and the feedstock oil enter the reactor together for reaction.

[0043] In some embodiments of the present invention, preferably, the catalyst has a composition shown in formula (I): MO a [R(COO) x ] b (I), wherein M is selected from at least one metal element of Group VB, Group VIB, Group VIII and Group IB, and R is selected from C3-C 20 Hydrocarbyl, x is selected from 1, 2, 3, a is selected from a positive number of 0-5, and b is selected from a positive number of 1-6.

[0044] In the present invention, unless otherwise specified, in Formula I, a is a positive number selected from 0-5, which means a is a positive number greater than 0 and not greater than 5.

[0045] In the present invention, as shown in the catalyst of formula I, M represents an active metal, R(COO) x represents an organic ligand, R represents a hydrocarbon group in the organic ligand, COO represents a coordinating group in the organic ligand, x represents the number of coordinating groups in the organic ligand, a represents the molar ratio of non-coordinating oxygen atoms connected to the active metal M to the total amount of metal, and b represents the molar ratio of the organic ligand to the total amount of metal. That is, the catalyst provided by the present invention is selected from at least one complex formed by a coordinate bond between an active metal and an organic ligand, wherein the organic ligand comprises a hydrocarbon group and a coordinating group, wherein the coordinating group is a -C(=O)-O group, and forms a coordination bond with the active metal central atom or central ion via an oxygen atom.

[0046] According to the present invention, in the catalyst of the present invention, the Group VB metal, Group VIB metal, Group VIII metal and Group IB metal having hydrogenation properties may be in the form of a central atom or a central ion or a central ion, depending on the metal used.

[0047] According to the present invention, the catalyst can be a mixture of multiple different complexes, and the molar ratios a and b of oxygen atoms and organic ligands to the total amount of metal in the catalyst composition are calculated values ​​based on metal content and elemental composition analysis, and can therefore be non-integer.

[0048] In some embodiments of the present invention, further preferably, in Formula I, M is selected from at least one metal element selected from V, Cr, Mo, W, Fe, Co, Ru, Ni, Cu and Pd, and R is selected from C4-C 20 Normal alkyl, C4-C 20 Isomeric alkyl, C5-C 20 Containing cycloalkyl and C6-C 20 Aryl, x is selected from 1 and 2, a is selected from a positive number of 1-3, and b is selected from a positive number of 2-5.

[0049] In some embodiments of the present invention, more preferably, in Formula I, M is selected from at least one metal element of Mo, W, Ni, V, Co and Fe, and R is selected from C5-C 11 Normal alkyl, C5-C 11 Isomeric alkyl, C5-C 12 Containing cycloalkyl and C6-C 12 Aryl.

[0050] In some embodiments of the present invention, in the catalyst, the organic ligand is selected from at least one of succinic acid, hexanoic acid, adipic acid, heptanoic acid, octanoic acid, nonanoic acid, ethylhexanoic acid, oleic acid, petroleum acid, salicylic acid, benzoic acid and phenylacetic acid.

[0051] In some embodiments of the present invention, the catalyst includes but is not limited to (MoCo)O 1.27 [(C7H 16 )(COO)] 2.45 、(Mo 0.7 Ni 0.3 )O 1.4 [(C7H 16 )(COO)] 3.27 、MoO[(i-C7H 16 )(COO)] 2.88 wait.

[0052] In some embodiments of the present invention, preferably, the infrared spectrum of the catalyst is between 700-1000 cm-1 There are MO and M=O vibration characteristic peaks at 1350-1450cm -1 and 1500-1610cm -1 The position has a characteristic peak of -C(=O)-O group coordinated with metal M;

[0053] In the present invention, unless otherwise specified, the catalyst consists solely of the complex and does not contain any solid support component. However, as needed, the catalyst of the present invention may also be present and used in the form of a composition with a liquid component capable of dispersing the catalyst, such as an organic solvent and an organic ligand compound.

[0054] In order to ensure the performance of the catalyst while reducing production costs, the content of active metals in the catalyst can be limited. Preferably, the active metal content in the catalyst, calculated as M, is 5-35wt%, for example, 5wt%, 8wt%, 10wt%, 12wt%, 15wt%, 18wt%, 20wt%, 22wt%, 25wt%, 30wt%, 35wt%, and any value in a range consisting of any two of these values, preferably 8-25wt%, more preferably 10-25wt%, and even more preferably 10-20wt%.

[0055] In the present invention, the purpose of the heat treatment is to enable the catalyst to have a dehydrogenation and polycondensation effect under a hydrogen-poor environment, thereby obtaining a coking raw material with a higher residual carbon content, while achieving efficient conversion of high-sulfur low-quality raw oil and increasing the production of high-quality low-sulfur petroleum coke.

[0056] In the present invention, unless otherwise specified, hydrogen-rich refers to an atmosphere containing hydrogen; hydrogen-poor refers to an atmosphere containing an inert gas, and the inert gas includes but is not limited to nitrogen, helium, argon, neon, etc., preferably nitrogen.

[0057] In some embodiments of the present invention, preferably, the heat treatment is performed in an air atmosphere or an inert atmosphere, preferably in an inert atmosphere, which includes but is not limited to a nitrogen atmosphere, an argon atmosphere, a helium atmosphere, and the like.

[0058] In some embodiments of the present invention, preferably, in step (2), the temperature of the heat treatment is 380-440°C, for example, 380°C, 400°C, 410°C, 420°C, 430°C, 440°C, and any value in the range consisting of any two values, preferably 400-430°C.

[0059] In some embodiments of the present invention, preferably, in step (2), the pressure of the heat treatment is 0.1-4 MPa, for example, 0.1 MPa, 0.5 MPa, 1 MPa, 2 MPa, 3 MPa, 4 MPa, and any value in the range consisting of any two values, preferably 1-3 MPa.

[0060] In some embodiments of the present invention, preferably, in step (2), the heat treatment time is 10-120 min, for example, 10 min, 20 min, 40 min, 50 min, 60 min, 80 min, 100 min, 120 min, and any value in the range consisting of any two values, preferably 20-100 min.

[0061] In some embodiments of the present invention, preferably, the liquid-solid component II satisfies: 0wt% < the increase in toluene insoluble matter ≤ 5wt%, 0wt% ≤ the reduction in the distillation section greater than 350°C < 15wt%; further preferably, the liquid-solid component II satisfies: 0wt% < the increase in toluene insoluble matter ≤ 3wt%; 0wt% ≤ the reduction in the distillation section greater than 350°C < 10wt%.

[0062] In the present invention, "0wt% < increase in toluene insoluble matter ≤ 5wt%" means that the increase in the toluene insoluble matter content does not exceed 5wt%; similarly, "0wt% ≤ reduction in the fraction greater than 350°C < 15wt%" means that the reduction in the fraction greater than 350°C is less than 15%.

[0063] In some embodiments of the present invention, preferably, the liquid-solid component II further satisfies: sulfur content ≤ 2 wt%; residual carbon content ≥ 7 wt%; further preferably, the liquid-solid component II satisfies: sulfur content ≤ 1.5 wt%; residual carbon content ≥ 10 wt%.

[0064] In the present invention, the separation and extraction is intended to remove the catalyst-containing solids from the liquid-solid component II (the reason for removing this portion is, firstly, because it contains almost all the catalyst metal components, and extraction of this portion can be used for catalyst circulation, effectively reducing the catalyst dosage; secondly, because this portion also contains metals from the raw materials, and removal can effectively reduce the ash content of the petroleum coke; at the same time, it is also desirable to retain as many coke-forming components other than metals as possible, which is beneficial to increasing the yield of petroleum coke); at the same time, a fraction suitable for coking feed is obtained by cutting (generally, a solid-free fraction with a temperature of >350°C). Therefore, the separation and extraction method is selected from extractive separation-distillation coupling and distillation cutting.

[0065] In a specific embodiment of the present invention, preferably, when the separation and extraction is selected from the extraction separation-distillation coupling, the extraction separation-distillation coupling process includes: contacting the liquid-solid component II with a solvent and performing extraction separation to obtain the external tail oil and desolidified oil; and distilling the desolidified oil to obtain the light component and the heavy component.

[0066] In some embodiments of the present invention, further preferably, the conditions for the extraction and separation include: a temperature of 40-300°C, for example, 40°C, 80°C, 100°C, 120°C, 150°C, 180°C, 200°C, 240°C, 300°C, and any value in a range consisting of any two numerical values, preferably 80-240°C; a pressure of 0.1-6 MPa, for example, 0.1 MPa, 0.5 MPa, 1 MPa, 2 MPa, 3 MPa, 5 MPa, 6 MPa, and any value in a range consisting of any two numerical values, preferably 0.1-3 MPa; and a weight ratio of the solvent to the desolidified oil of 1-10:1, for example, 1:1, 2:1, 3:1, 4:1, 5:1, 8:1, 10:1, and any value in a range consisting of any two numerical values, preferably 1-5:1.

[0067] In some embodiments of the present invention, it is further preferred that the distillation temperature is ≥330°C, for example, 330°C, 340°C, 350°C, 360°C, 370°C, and any value in the range consisting of any two values, preferably 330-370°C.

[0068] In the present invention, a wide range of solvents can be selected, as long as the solvent can remove the solid content (catalyst, heavy metals) in the liquid-solid component II. Preferably, the solvent is selected from at least one of C3-C8 alkanes, C3-C8 alkenes, toluene, and light naphtha, and more preferably selected from C4-C5 alkanes and / or toluene.

[0069] In another embodiment of the present invention, preferably, when the separation and extraction is selected from distillation cutting, the temperature of the distillation cutting is ≥330°C, for example, 330°C, 340°C, 350°C, 360°C, 370°C, and any value in the range consisting of any two values, preferably 330-370°C.

[0070] In the present invention, the light component is selected from liquid components with a distillation range of less than 330°C; the heavy component contains the main coke-forming components in the hydrodesulfurization product. Preferably, the sulfur content of the coking feedstock is ≤1.5wt%, for example, 0.1wt%, 0.5wt%, 0.8wt%, 1wt%, 1.2wt%, 1.5wt%, and any value in a range consisting of any two values, preferably 0.5-1.2wt%; the residual carbon content is ≥8wt%, for example, 8wt%, 10wt%, 12wt%, 15wt%, 18wt%, 20wt%, and any value in a range consisting of any two values, preferably 10-20wt%; and the distillation range is ≥330°C.

[0071] In some embodiments of the present invention, the method preferably further comprises: returning a portion of the off-gassing oil to undergo the hydrodesulfurization pretreatment; and discharging the remaining off-gassing oil. This arrangement can further improve the conversion rate of the feedstock oil and reduce catalyst costs.

[0072] In the present invention, the weight ratio of part of the external tail oil and the remaining part of the external tail oil has a wide selection range, that is, the weight ratio of part of the external tail oil and the remaining part of the external tail oil is 0-100:100-0. The above weight ratio is selected and adjusted based on specific working conditions.

[0073] In some embodiments of the present invention, preferably, in step (4), the conditions of the coking treatment include: a temperature of 500-600°C, for example, 500°C, 520°C, 550°C, 580°C, 600°C, and any value in a range consisting of any two numerical values; a pressure of 0.15-0.3MPa, for example, 0.15MPa, 0.2MPa, 0.25MPa, 0.3MPa, and any value in a range consisting of any two numerical values; a time of 1-5h; and a circulation ratio of 0-1, for example, 0, 0.2, 0.5, 0.6, 0.8, 1, and any value in a range consisting of any two numerical values.

[0074] In the present invention, the temperature of the coking treatment refers to the outlet temperature of the coking furnace; the pressure of the coking treatment refers to the top pressure of the coking furnace; the circulation ratio is the ratio of the circulating oil volume to the fresh raw oil volume, and the conventional circulating oil is the heaviest part of the coking distillate oil and is recycled.

[0075] In some embodiments of the present invention, preferably, the low-sulfur petroleum coke satisfies the following requirements: sulfur content ≤ 2 wt%, volatile matter content ≤ 12 wt%, and ash content ≤ 0.5 wt%.

[0076] In the present invention, unless otherwise specified, low-sulfur petroleum coke with a sulfur content ≤ 2 wt% is only subject to restrictions on the sulfur content, volatile matter content and ash content, and has no restrictions on the metal content.

[0077] Compared with the prior art of directly subjecting residual oil to coking treatment, the method provided by the present invention adopts hydrodesulfurization pretreatment, which will reduce the sulfur content in the petroleum coke, but also reduce the overall petroleum coke yield; by adding a heat treatment step and coking treatment conditions, the sulfur content can be reduced while increasing the overall petroleum coke yield.

[0078] The second aspect of the present invention provides a schematic diagram of the structure of a device for increasing the production of high-quality low-sulfur petroleum coke. Figure 1-2 As shown by Figure 1-2 It can be seen that the device includes a reaction unit I, a heat treatment unit II, a separation and extraction unit III and a coking unit IV connected in sequence;

[0079] Among them, the reaction unit I is used to perform hydrodesulfurization pretreatment on the raw oil 1 and the catalyst 2 in the presence of hydrogen 3 to obtain gas I 4 and liquid-solid components I 5; the heat treatment unit II is used to perform heat treatment on the liquid-solid components I 5 to obtain gas II 6 and liquid-solid components II 7; the separation and extraction unit III is used to separate and extract the liquid-solid components II 7 to obtain external tail oil 8, light components 10 and heavy components 11; the coking unit IV is used to perform coking treatment on the heavy components 11 as a coking raw material to obtain low-sulfur petroleum coke 12 with a sulfur content of ≤2wt%.

[0080] In the present invention, preferably, Figure 1 As shown, the separation and extraction unit III includes: an extraction and separation section III-1 and a distillation section III-2 connected in sequence, the extraction and separation section III-1 is used to contact the liquid-solid component II 7 with a solvent and perform extraction and separation, the tower bottom obtains the external tail oil 8, and the tower top obtains the desolidified oil 9; the distillation section III-2 is used to distill the desolidified oil 9, the tower top obtains the light component 10, and the tower bottom obtains the heavy component 11.

[0081] In the present invention, preferably, Figure 2 As shown, the separation and extraction unit III is selected from the distillation cutting tower III-3, which is used to distill and cut the liquid-solid component II 7, obtain the external tail oil 8 in the tower bottom, obtain the light component 10 at the tower top, and obtain the heavy component 11 in the tower side line.

[0082] In the present invention, it is further preferred that Figure 1-2 As shown, the bottom of the extraction unit III is connected to the reaction unit I, which is used to return part of the tail oil and perform the hydrodesulfurization pretreatment.

[0083] In the present invention, Figure 1 As shown, preferably, the coking unit IV includes: a coking furnace IV-1 and a fractionating tower IV-2 connected in sequence, the coking furnace IV-1 is used to coke the heavy component 11 as a coking raw material, and the bottom of the tower obtains low-sulfur petroleum coke 12, and the top of the tower obtains a gas-liquid mixture 17; the fractionating tower IV-2 is used to fractionate the gas-liquid mixture 17 to obtain coking gas 13, coking naphtha 14, coking diesel 15 and coking wax oil 16.

[0084] In the present invention, Figure 1-2 As shown, the reaction unit I is selected from a slurry bed reactor, and gas I4 is obtained at the top of the tower, and liquid-solid components I5 are obtained in the bottom of the tower; the heat treatment unit II is selected from a reactor, including but not limited to a fixed bed reactor, a high-pressure reactor, etc., and gas II6 is obtained at the top of the tower, and liquid-solid components II7 are obtained in the bottom of the tower; the extraction separation part III-1 is selected from a solid-liquid separation device, including but not limited to an extraction tower, etc.; the distillation part III-2 includes but is not limited to a distillation tower; the distillation cutting tower III-3 includes but is not limited to a distillation tower.

[0085] The present invention provides a schematic diagram of the structure of a device for increasing the production of high-quality low-sulfur petroleum coke, as shown in FIG. Figure 1 As shown, the device includes a reaction unit I, a heat treatment unit II, a separation and extraction unit III and a coking unit IV connected in sequence;

[0086] Wherein, the reaction unit I is selected from a slurry bed reactor, which is used to perform hydrodesulfurization pretreatment on the raw oil 1 and the catalyst 2 in the presence of hydrogen 3, and obtain gas I 4 at the top of the tower and liquid-solid components I 5 at the bottom of the tower;

[0087] The heat treatment unit II is selected from a fixed bed reactor, which is used to heat treat the liquid-solid components I 5, obtain gas II 6 at the top of the tower, and obtain liquid-solid components II 7 at the bottom of the tower;

[0088] The separation and extraction unit III includes an extraction and separation section III-1 and a distillation section III-2 connected in sequence. The extraction and separation section III-1 is selected from a solvent extraction column, and is used to contact the liquid-solid component II 7 with a solvent and perform extraction and separation, thereby obtaining a desolidified oil 9 at the top of the column and an external tail oil 8 at the bottom of the column; the distillation section III-2 is selected from a distillation column, and is used to distill the desolidified oil 9, thereby obtaining a light component 10 at the top of the column and a heavy component 11 at the bottom of the column;

[0089] The coking unit IV includes a coking furnace IV-1 and a fractionating tower IV-2 connected in sequence. The coking furnace IV-1 is used to use the heavy component 11 as a coking raw material for the coking process, and a gas-liquid mixture 17 is obtained at the top of the tower, and low-sulfur petroleum coke 12 is obtained at the bottom of the tower; the fractionating tower IV-2 is used to fractionate the gas-liquid mixture 17, and coking gas 13 is obtained at the top of the tower. Coking naphtha 14 and coking diesel 15 are drawn out from the side of the tower, and coking wax oil 16 is obtained at the bottom of the tower.

[0090] Another schematic diagram of the device structure for increasing the production of high-quality low-sulfur petroleum coke provided by the present invention is as follows: Figure 2 As shown, the device includes a reaction unit I, a heat treatment unit II, a separation and extraction unit III and a coking unit IV connected in sequence;

[0091] Wherein, the reaction unit I is selected from a slurry bed reactor, which is used to perform hydrodesulfurization pretreatment on the raw oil 1 and the catalyst 2 in the presence of hydrogen 3, and obtain gas I 4 at the top of the tower and liquid-solid components I 5 at the bottom of the tower;

[0092] The heat treatment unit II is selected from a fixed bed reactor, which is used to heat treat the liquid-solid components I 5, obtain gas II 6 at the top of the tower, and obtain liquid-solid components II 7 at the bottom of the tower;

[0093] The separation and extraction unit III is selected from the distillation cutting tower III-3, which is used to distill and cut the liquid-solid component II 7, obtain the external tail oil 8 in the tower bottom, obtain the light component 10 at the top of the tower, and obtain the heavy component 11 in the side line of the tower;

[0094] The coking unit IV includes a coking furnace IV-1 and a fractionating tower IV-2 connected in sequence. The coking furnace IV-1 is used to use the heavy component 11 as a coking raw material for the coking process, and a gas-liquid mixture 17 is obtained at the top of the tower, and low-sulfur petroleum coke 12 is obtained at the bottom of the tower; the fractionating tower IV-2 is used to fractionate the gas-liquid mixture 17, and coking gas 13 is obtained at the top of the tower. Coking naphtha 14 and coking diesel 15 are drawn out from the side line of the tower, and coking wax oil 16 is obtained at the bottom of the tower.

[0095] According to a particularly preferred embodiment of the present invention, a method for increasing the production of high-quality low-sulfur petroleum coke comprises the following steps:

[0096] (1) performing a hydrodesulfurization pretreatment on the crude oil and the catalyst in the presence of hydrogen to obtain a liquid-solid component I and a gas I;

[0097] (2) heat-treating the liquid-solid component I to obtain a liquid-solid component II and a gas II;

[0098] (3) separating and extracting the liquid-solid component II to obtain tail oil, light components, and heavy components;

[0099] (4) coking the heavy component as the coking raw material to obtain low-sulfur petroleum coke with a sulfur content of ≤2 wt%;

[0100] The separation and extraction is selected from extraction separation-distillation coupling and distillation cutting; the extraction separation-distillation coupling process comprises: contacting the liquid-solid component II with a solvent and performing extraction separation to obtain the external tail oil and desolidified oil, and distilling the desolidified oil to obtain the light component and the heavy component; the distillation and distillation cutting temperatures are each independently 330-370°C;

[0101] Wherein, the catalyst has the composition shown in formula (I): MO a [R(COO) x ] b (I), wherein M is selected from at least one metal element of Group VB, Group VIB, Group VIII and Group IB, and R is selected from C3-C 20 Hydrocarbyl, x is selected from 1, 2, 3, a is selected from a positive number of 0-5, and b is selected from a positive number of 1-6.

[0102] The present invention will be described in detail below through examples.

[0103] The raw oil A is a high-sulfur low-quality raw oil, and its specific properties are shown in Table 1.

[0104] Table 1

[0105]

[0106] The metal content of the obtained product was determined using a SPECTRO ARCOS SOP plasma optical emission spectrometer using inductively coupled plasma optical emission spectrometry (ICP-OES). The measurement conditions were a closed optical chamber filled with argon, vertical observation, and a wavelength range of 130-770 nm.

[0107] The elemental composition of the obtained product was determined as follows: the C and H contents were determined using the SH 0656 method using an Italian Cara Erba EA1110 elemental analyzer; the S content was determined using the energy dispersive X-ray fluorescence spectrometry method GB17040 using an Oxford Lab-X3500 desktop XRF analyzer; and the O content was determined using the O-content method.

[0108] The infrared spectrum of the obtained product was measured using a NICOLET IS50 spectrometer from Thermo Fisher Scientific. The measurement conditions were as follows: the scanning wavelength was from 400 cm -1 -4000cm -1The number of scans is 16. ZnSe crystal and HgCdTe infrared detector are used together to measure the attenuated total reflectance (ATR) of the sample with a resolution of 4cm -1 .

[0109] The metal content of the catalysts C1-C2 was determined by inductively coupled plasma optical emission spectrometry (ICP-OES), and the elemental composition of the catalysts C1-C2 was determined by the corresponding method. Based on the measured metal content and elemental composition, the compositions of the catalysts C1-C2 were (MoCo)O 1.27 (C7H 16 COO) 2.45 and(Mo 0.7 Ni 0.3 )O 1.4 (C7H 16 COO) 3.27 Wherein, the infrared spectrum of the above catalyst C1-C2 is as follows Figure 3 As shown by Figure 3 It can be seen that the catalysts C1-C2 are all in the range of 700-1000cm -1 、1350-1450cm -1 and 1500-1610cm -1 There is a characteristic peak at the position. That is, 700-1000cm -1 There are MO and M=O vibration characteristic peaks at 1350-1450cm -1 and 1500-1610cm -1 There is a characteristic peak of -C(=O)-O group coordinated with metal at the position, and 1350-1450cm -1 A characteristic peak at 1500-1610 cm -1 The distance between the peaks of a characteristic peak at the position is greater than 145 cm -1 , indicating that at least part of the complexes of catalysts C1-C2 have a bimetallic monodentate coordination structure (ELN: 120063-1-2021-7789-043, 120063-1-2021-7789-011; lims: YN-20210308-00604-1).

[0110] Example 1

[0111] (1) The above-mentioned raw oil A and catalyst C1 ((Mo 0.7 Ni 0.3 )O 1.4 [(C7H 16 )COO)] 3.27, active metal content of 12.76 wt%) was subjected to hydrodesulfurization pretreatment in a slurry bed reactor in the presence of hydrogen to obtain gas I and liquid-solid component I. The operating conditions of the above hydrodesulfurization pretreatment are shown in Table 2;

[0112] (2) The liquid-solid component I was heat-treated in a nitrogen atmosphere to obtain a gas II and a liquid-solid component II. The operating conditions, product distribution, and properties of the heat treatment are shown in Table 2.

[0113] (3) contacting the liquid-solid fraction II with a solvent and performing extraction separation to obtain desolidified oil and external tail oil, distilling the desolidified oil at 350° C. to obtain light components and heavy components, and using the heavy components as a coking feedstock. The above operating conditions and product properties are shown in Table 3;

[0114] (4) The above coking raw materials are subjected to coking treatment to obtain coking gas, coking naphtha, coking diesel, coking wax oil and low-sulfur petroleum coke. The operating conditions, product distribution and properties of the low-sulfur petroleum coke of the above coking treatment are shown in Table 4.

[0115] Example 2

[0116] (1) The above-mentioned raw oil A and catalyst C2 ((MoCo)O 1.27 [(C7H 16 )(COO)] 2.45 , active metal content of 11.75 wt%) was subjected to hydrodesulfurization pretreatment in a slurry bed reactor in the presence of hydrogen to obtain gas I and liquid-solid component I. The operating conditions of the above hydrodesulfurization pretreatment are shown in Table 2;

[0117] (2) The liquid-solid component I was heat-treated in a nitrogen atmosphere to obtain a gas II and a liquid-solid component II. The operating conditions, product distribution, and properties of the heat treatment are shown in Table 2.

[0118] (3) The liquid-solid component II was directly distilled and cut at 350°C, and the obtained heavy component was used as a coking raw material. The above operating conditions and product properties are shown in Table 3;

[0119] (4) The above-mentioned heavy components are subjected to coking treatment to obtain coking gas, coking naphtha, coking diesel, coking gas oil and low-sulfur petroleum coke. The operating conditions, product distribution and properties of the low-sulfur petroleum coke of the above-mentioned coking treatment are shown in Table 4.

[0120] Example 3

[0121] According to the method of Example 1, the difference is that

[0122] In step (1), the conditions for hydrodesulfurization pretreatment are carried out according to the data in Table 2;

[0123] In step (2), gas II and liquid-solid component II are obtained. The product distribution and properties are shown in Table 2;

[0124] In step (3), the tail oil, light components and heavy components are obtained. The properties of the products are shown in Table 3.

[0125] In step (4), coking gas, coking naphtha, coking diesel, coking gas oil and low-sulfur petroleum coke are obtained. The product distribution and properties of low-sulfur petroleum coke are shown in Table 4.

[0126] Example 4

[0127] According to the method of Example 1, the difference is that

[0128] In step (2), the heat treatment conditions are carried out according to the data in Table 2 to obtain gas II and liquid-solid component II. The operating conditions, product distribution and properties of the above heat treatment are shown in Table 2;

[0129] In step (3), the tail oil, light components and heavy components are obtained. The properties of the products are shown in Table 3.

[0130] In step (4), coking gas, coking naphtha, coking diesel, coking gas oil and low-sulfur petroleum coke are obtained. The product distribution and properties of low-sulfur petroleum coke are shown in Table 4.

[0131] Example 5

[0132] According to the method of Example 1, the difference is that

[0133] In step (3), the distillation temperature is carried out according to the data in Table 3 to obtain the tail oil, light components and heavy components. The operating conditions and product properties of the above distillation are shown in Table 3;

[0134] In step (4), coking gas, coking naphtha, coking diesel, coking gas oil and low-sulfur petroleum coke are obtained. The product distribution and properties of low-sulfur petroleum coke are shown in Table 4.

[0135] Example 6

[0136] According to the method of Example 1, the difference is that

[0137] In step (4), the coking treatment conditions are carried out according to the data in Table 4 to obtain coking gas, coking naphtha, coking diesel, coking gas oil and low-sulfur petroleum coke. The product distribution and properties of low-sulfur petroleum coke are shown in Table 4.

[0138] Comparative Example 1

[0139] According to the method of Example 1, the difference is that

[0140] There is no step (2), that is, the liquid-solid component I obtained in step (1) is directly subjected to extraction separation, distillation, and coking treatment to obtain coking gas, coking naphtha, coking diesel, coking wax oil, and petroleum coke. The product distribution and low petroleum coke properties are shown in Table 4.

[0141] Table 2

[0142]

[0143] Table 3

[0144]

[0145] Note: *- weight ratio of solvent to desolidified oil.

[0146] Table 4

[0147]

[0148]

[0149] Note: #-Total yield of low-sulfur petroleum coke = content of fractions above 350°C in liquid-solid component II × content of low-sulfur petroleum coke in the coking product. Taking Example 1 as an example, 46.10 wt% × 32.6 wt% = 15 wt%.

[0150] It can be seen from the data in Tables 2-4 that, compared with Comparative Example 1, the method provided by the present invention has a lower coking wax oil yield and a higher low-sulfur petroleum coke yield; at the same time, the sulfur content of the low-sulfur petroleum coke can also meet the standards for high-quality low-sulfur coke, can be used for negative electrode materials, has higher value, and meets environmental protection requirements.

[0151] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A method for increasing the production of high-quality low-sulfur petroleum coke, characterized in that: The method comprises: performing hydrodesulfurization pretreatment on raw oil and catalyst, performing heat treatment on the obtained liquid-solid component I, performing separation and extraction on the obtained liquid-solid component II, and performing coking treatment on the obtained coking raw material to obtain low-sulfur petroleum coke with a sulfur content of ≤2wt%; Wherein, the catalyst is selected from at least one complex formed by active metal and organic ligand bonded by coordination bonds.

2. The method according to claim 1, wherein The method comprises the following steps: (1) subjecting the feedstock oil and the catalyst to the hydrodesulfurization pretreatment in the presence of hydrogen to obtain the liquid-solid component I and the gas I; (2) subjecting the liquid-solid component I to the heat treatment to obtain the liquid-solid component II and the gas II; (3) separating and extracting the liquid-solid component II to obtain tail oil, light components, and heavy components; (4) using the heavy component as the coking raw material to perform the coking process to obtain the low-sulfur petroleum coke; Wherein, the separation and extraction is selected from extraction separation-distillation coupling and distillation cutting.

3. The method according to claim 1 or 2, wherein: The conditions of the hydrodesulfurization pretreatment include: temperature of 380-440°C; hydrogen partial pressure of 8-20 MPa; volume space velocity of 0.05-0.6 h -1 ; The concentration of the catalyst calculated as metal element is 200-20000 μg / g; Preferably, the conditions for the hydrodesulfurization pretreatment include: a temperature of 400-430°C; a hydrogen partial pressure of 10-18 MPa; a volume space velocity of 0.1-0.5 h -1 ; The concentration of the catalyst calculated as metal element is 500-10000 μg / g; Preferably, the hydrodesulfurization pretreatment is carried out in a slurry bed reactor; Preferably, the raw oil has a sulfur content of ≥3wt%, an asphaltene content of ≥11wt%, a heavy metal content in terms of Ni and / or V of ≥150ppm, and a kinematic viscosity at 100°C of ≥2000mm 2 / s; Preferably, the feedstock oil is selected from high-sulfur low-quality oil, preferably at least one selected from high-sulfur crude oil, high-sulfur deasphalted oil and high-sulfur vacuum residue.

4. The method according to any one of claims 1 to 3, wherein: The catalyst has a composition shown in formula (I): MO a [R(COO) x ] b (I), wherein M is selected from at least one metal element of Group VB, Group VIB, Group VIII and Group IB, and R is selected from C3-C 20 A hydrocarbon group, x is selected from 1, 2, and 3, a is selected from a positive number of 0 to 5, and b is selected from a positive number of 1 to 6; Further preferably, in Formula I, M is selected from at least one metal element selected from V, Cr, Mo, W, Fe, Co, Ru, Ni, Cu and Pd, and R is selected from C4-C 20 Normal alkyl, C4-C 20 Isomeric alkyl, C5-C 20 Containing cycloalkyl and C6-C 20 Aryl, x is selected from 1 and 2, a is selected from a positive number of 1-3, and b is selected from a positive number of 2-5; More preferably, in Formula I, M is selected from at least one metal element of Mo, W, Ni, V, Co and Fe, and R is selected from C5-C 11 Normal alkyl, C5-C 11 Isomeric alkyl, C5-C 12 Containing cycloalkyl and C6-C 12 Aryl.

5. The method according to claim 4, wherein The infrared spectrum of the catalyst is between 700-1000 cm -1 There are MO and M=O vibration characteristic peaks at 1350-1450cm -1 and 1500-1610cm -1 The position has a characteristic peak of -C(=O)-O group coordinated with metal M; Preferably, the active metal content in the catalyst calculated as M is 5-35 wt%, preferably 8-25 wt%, more preferably 10-25 wt%, and even more preferably 10-20 wt%.

6. The method according to any one of claims 1 to 5, wherein: The heat treatment conditions include: temperature of 380-440°C, preferably 400-430°C; pressure of 0.1-4 MPa, preferably 1-3 MPa; time of 10-120 min, preferably 20-100 min; Preferably, the heat treatment is carried out in an air atmosphere or an inert atmosphere, preferably in an inert atmosphere; Preferably, the liquid-solid component II satisfies the following conditions: 0 wt% < increase in toluene insoluble matter ≤ 5 wt%; 0 wt% ≤ decrease in the fraction greater than 350°C < 15 wt%; Further preferably, the liquid-solid component II satisfies: 0 wt% < increase in toluene insoluble matter ≤ 3 wt%; 0 wt% ≤ decrease in the fraction greater than 350°C < 10 wt%; Preferably, the liquid-solid component II further satisfies: sulfur content ≤ 2 wt%; residual carbon content ≥ 7 wt%; Further preferably, the liquid-solid component II satisfies: sulfur content ≤ 1.5 wt%; residual carbon content ≥ 10 wt%.

7. The method according to any one of claims 2 to 6, wherein: When the separation and extraction is selected from the extraction separation-distillation coupling, the extraction separation-distillation coupling process includes: contacting the liquid-solid component II with a solvent and performing extraction separation to obtain the external tail oil and desolidified oil; distilling the desolidified oil to obtain the light component and the heavy component; Preferably, the extraction separation conditions include: a temperature of 40-300° C., preferably 80-240° C.; a pressure of 0.1-6 MPa, preferably 0.1-3 MPa; a weight ratio of the solvent to the desolidified oil of 1-10:1, preferably 1-5:1; Preferably, the distillation temperature is ≥330°C, preferably 330-370°C; Preferably, the solvent is selected from at least one of C3-C8 alkanes, C3-C8 olefins, toluene and light naphtha, preferably selected from C4-C5 alkanes and / or toluene; Preferably, when the separation and extraction is selected from distillation cutting, the temperature of the distillation cutting is ≥330°C, preferably 330-370°C; Preferably, the sulfur content of the coking raw material is ≤1.5wt%, preferably 0.5-1.2wt%; the residual carbon content is ≥8wt%, preferably 10-20wt%; Preferably, the method further comprises: returning part of the off-gassing tail oil and performing the hydrodesulfurization pretreatment; and discharging the remaining part of the off-gassing tail oil.

8. The method according to any one of claims 1 to 7, wherein: The coking treatment conditions include: temperature of 500-600°C; pressure of 0.15-0.3 MPa; time of 1-5 hours; circulation ratio of 0-1; Preferably, the gas-liquid mixture obtained by the coking process is fractionated to obtain coking gas, coking naphtha, coking diesel and coking gas oil; Preferably, the low-sulfur petroleum coke further meets the following requirements: volatile matter content ≤ 12 wt %, ash content ≤ 0.5 wt %.

9. A device for increasing the production of high-quality low-sulfur petroleum coke, characterized in that: The device comprises a reaction unit, a heat treatment unit, a separation and extraction unit and a coking unit connected in sequence; The reaction unit is used to perform hydrodesulfurization pretreatment on the raw oil and the catalyst in the presence of hydrogen to obtain gas I and liquid-solid component I; the heat treatment unit is used to perform heat treatment on the liquid-solid component I to obtain gas II and liquid-solid component II; the separation and extraction unit is used to separate and extract the liquid-solid component II to obtain tail oil, light components and heavy components; and the coking unit is used to perform coking treatment on the heavy components as coking raw materials to obtain low-sulfur petroleum coke with a sulfur content of ≤2wt%.

10. The device according to claim 9, wherein The reaction unit is selected from a slurry bed reactor; Preferably, the separation and extraction unit comprises: an extraction and separation section and a distillation section connected in sequence, the extraction and separation section is used to contact the liquid-solid component II with a solvent and perform extraction and separation, the tower bottom obtains the external tail oil, the tower top obtains the desolidified oil, the distillation section is used to distill the desolidified oil, the tower top obtains the light component, and the tower bottom obtains the heavy component; Alternatively, the separation and extraction unit is selected from a distillation cutting tower, which is used to distill and cut the liquid-solid component II, obtain the external tail oil in the tower bottom, obtain the light component at the tower top, and obtain the heavy component in the tower side line; Further preferably, the bottom of the extraction unit is connected to the reaction unit for returning part of the tail oil to undergo the hydrodesulfurization pretreatment; Preferably, the coking unit comprises: a coking furnace and a fractionating tower connected in sequence, the coking furnace is used to use the heavy component as the coking raw material for the coking process, low-sulfur petroleum coke is obtained at the bottom of the tower, and a gas-liquid mixture is obtained at the top of the tower; the fractionating tower is used to fractionate the gas-liquid mixture to obtain coking gas, coking naphtha, coking diesel and coking wax oil.

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