Production method of impregnated asphalt for graphite electrode

Abstract

The invention discloses a production method of impregnated asphalt for a graphite electrode. The method comprises the following steps: (1) hydrofining catalytic slurry oil to obtain a hydrofined product; (2) carrying out reduced pressure distillation on the hydrofining product obtained in the step (1) to obtain light distillate oil and heavy distillate oil; (3) carrying out thermal polymerization reaction on the heavy distillate oil obtained in the step (2), and meanwhile, refluxing the flashed light distillate to a polymerization reaction system to obtain a polymerization product; and (4) carrying out carbonization reaction on the polymerization product obtained in the step (3) and the light distillate oil obtained in the step (2) to obtain the impregnated asphalt. The impregnated asphalt produced by the method is low in QI, high in beta resin content, appropriate in softening point and coking value, and low in ash content and moisture content.

Description

A method for producing impregnated bitumen for graphite electrodes Technical Field

[0001] This invention belongs to the field of carbon material preparation, and specifically relates to a method for producing impregnated pitch for ultra-high power graphite electrodes. Background Technology

[0002] With the increasing production of ultra-high power graphite electrodes, impregnating bitumen, as a filler required for the production of ultra-high power graphite electrodes, has become a hot research topic. Combining the Chinese national standard GB / T 35074-2018 coking impregnating bitumen and the Chinese industry standard YB / T 4090-2015 ultra-high power graphite electrodes, the high-standard impregnating bitumen used for ultra-high power graphite electrodes should have a quinoline insoluble (QI) content of no more than 0.5%, a toluene insoluble (TI) content of no less than 10 wt%, a β-resin content (equal to the toluene insoluble content minus the quinoline insoluble content) of no less than 15 wt%, a coking value of no less than 47 wt%, a softening point of 80℃~95℃, an ash content of no more than 0.05 wt%, a moisture content of no more than 0.2 wt%, and good high-temperature fluidity. Currently, coal tar is generally selected as the raw material for producing impregnating bitumen because it is rich in polycyclic aromatic hydrocarbons, resulting in impregnating bitumen with a high β-resin content. However, the high native QI content in coal tar (generally 3wt% to 5wt%) is not conducive to the preparation of high-quality impregnated pitch with high β resin content.

[0003] CN116790276A discloses a method for separating components from ethylene tar to prepare impregnated bitumen that meets the requirements of quinoline insoluble matter QI < 0.3% and β resin > 15%, demonstrating the possibility of producing impregnated bitumen from other heavy oils rich in aromatics. Catalytic cracking slurry oil is a byproduct of the catalytic cracking process, with low cost, containing a large amount of polycyclic aromatic hydrocarbons, and having a lower primary QI content than coal tar, thus possessing the potential for producing impregnated bitumen.

[0004] CN106701134B discloses a method for obtaining petroleum-based impregnated bitumen from heavy oils such as catalytic cracking slurry through purification, blending, thermal polymerization, refining, and molding. However, the softening point is higher than 110℃, which is difficult to meet the requirements of ultra-high power graphite electrodes.

[0005] Existing technologies using catalytic oil slurry as raw material typically involve directly polymerizing the catalytic oil slurry to prepare impregnated bitumen. However, the quality of the impregnated bitumen prepared using existing methods, such as its QI value and softening point, is insufficient in various aspects, making it difficult to meet the requirements of ultra-high power graphite electrodes. Therefore, the production method of impregnated bitumen for graphite electrodes needs further improvement. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a method for producing impregnating bitumen for graphite electrodes. The impregnating bitumen produced by this method has a low QI, high β-resin content, suitable softening point and coking value, and low ash and moisture content.

[0007] This invention provides a method for producing impregnated bitumen for graphite electrodes. The method includes:

[0008] (1) The catalytic slurry is hydrotreated to obtain the hydrotreated product;

[0009] (2) The hydrorefined product obtained in step (1) is subjected to vacuum distillation to obtain light distillate oil and heavy distillate oil;

[0010] (3) The heavy distillate oil obtained in step (2) is subjected to thermal polymerization reaction, while the light distillate that is flashed is refluxed into the polymerization reaction system to obtain the polymerization product;

[0011] (4) The polymer product obtained in step (3) is carbonized with the light distillate oil obtained in step (2) to obtain impregnated asphalt.

[0012] According to the present invention, the 5% distillation temperature of the catalytic slurry in step (1) is 280°C to 380°C, preferably 300°C to 350°C, and the 95% distillation temperature is 510°C to 600°C, preferably 530°C to 590°C; the aromatic carbon content is 30wt% to 90wt%, preferably 50wt% to 80wt%; the ash content is <0.07wt%, preferably <0.06%; and the sulfur content is 0.85wt% to 1.20wt%.

[0013] According to the present invention, in step (1), the hydrorefining reaction of the catalytic slurry adopts a conventional hydrorefining process in the art, the purpose of which is to remove impurities such as sulfur and nitrogen from the catalytic cracking slurry, while generating a certain amount of cycloalkanes with side chains. The hydrorefining reaction adopts a fixed-bed hydrorefining process, and multiple reactors or catalyst beds can be set up. Preferably, the hydrorefining reaction is set up with at least 2 catalyst beds, and more preferably 3 to 6 catalyst beds.

[0014] According to the present invention, in step (1), the hydrorefining reaction employs a hydrorefining catalyst. The catalyst uses an oxide of at least one Group VIB metal, such as W or Mo, as its active component, and also contains Group VIII metal oxides, such as NiO and / or CoO, supported on an alumina substrate. Preferably, the catalyst, based on catalyst mass, contains 5.0 wt% to 18.0 wt% of Group VIB metals as oxides and 0.5 wt% to 5.0 wt% of Group VIII metals as oxides. The hydrorefining catalyst is preferably a residue desulfurization catalyst, and can be an existing residue desulfurization catalyst, such as the FZC-3XX series residue desulfurization catalysts developed by the Dalian Petrochemical Research Institute of China Petroleum & Chemical Corporation, such as FZC-301A and FZC-303.

[0015] According to the present invention, a hydroprotectant is preferably loaded before the hydrorefining catalyst in step (1). The hydroprotectant is preferably composed of Group VIB and / or Group VIII metal oxides as active components, preferably Mo and Ni. Preferably, based on the mass of the hydroprotectant, the content of Group VIB metal oxides in the hydroprotectant is 3 wt% to 12 wt%, and the content of Group VIII metal oxides is 0.2 wt% to 5.0 wt%. The hydroprotectant is preferably a residue hydroprotectant, and existing residue hydroprotectants can be used, such as the FZC series hydroprotectants developed by the Dalian Petrochemical Research Institute of China Petroleum & Chemical Corporation, which can slow down the deposition of raw coke and metal sulfides while having a certain capacity to accommodate them, such as FZC-103A and FZC-12B hydroprotectants.

[0016] According to the present invention, in step (1), when the hydrogenation protectant and the hydrogenation refining catalyst are loaded simultaneously, the loading volume ratio of the hydrogenation protectant and the hydrogenation refining catalyst is 1:3 to 5.5, preferably 1:3 to 5.

[0017] According to the present invention, in step (1), the reaction conditions for the hydrorefining reaction are as follows: reaction temperature is 250℃~420℃, preferably 280℃~360℃; hydrogen partial pressure is 1MPa~10MPa, preferably 2MPa~5MPa; hydrogen-to-oil volume ratio is 500~1500, preferably 700~1400; and liquid hourly space velocity is 0.1h. -1 ~1.2h -1 Preferably 0.2h -1 ~0.9h -1 .

[0018] According to the present invention, the light distillate oil in step (2) has a 95% distillation point temperature of 390℃~430℃ and a sulfur content of 0.65wt%~0.90wt%; the heavy distillate oil has a 5% distillation point temperature of 410℃~440℃ and a sulfur content of 0.75wt%~1.20wt%.

[0019] According to the present invention, in the hydrocarbon composition distribution of the heavy distillate oil in step (2), the mass percentage of 3- to 5-cyclic aromatics is 58.7 wt% to 67.3 wt%, the quinoline insoluble content is <0.015 wt%, and the toluene insoluble content is 6.50 wt% to 10.0 wt%. In the hydrocarbon composition distribution of the light distillate oil in step (2), the mass percentage of monocyclic and bicyclic aromatics is 18.9 wt% to 28.6 wt%, the quinoline insoluble content is <0.015 wt%, and the toluene insoluble content is 6.50 wt% to 10.0 wt%, which contains more alkyl side chains and cycloalkanes compared to the heavy distillate oil.

[0020] According to the present invention, in step (2), the thermal polymerization reaction of the heavy distillate oil is carried out in a reactor equipped with a reflux distillation device. The conditions for the thermal polymerization reaction are: reaction pressure of 0.5 MPa to 2.0 MPa, preferably 1.2 MPa to 2.0 MPa; reaction temperature of 340°C to 460°C, preferably 350°C to 385°C; and reaction time of 4 h to 8 h, preferably 5.5 h to 7 h.

[0021] According to the present invention, in step (3), when the polymerization reaction occurs, a light distillate is flash-distilled from the system; the light distillate is refluxed back into the polymerization reaction system. This can increase the polycyclic aromatic hydrocarbon content in the reaction system, thereby polymerizing to form more toluene-insoluble matter. Further, the remixing ratio is 8wt% to 15wt%, preferably 10wt% to 12wt%, by mass. The remixing ratio is the proportion of light distillate to heavy distillate oil in the feed.

[0022] According to the present invention, in step (4), the polymerization product is co-carbonized with the light distillate oil. The mass ratio of the light distillate oil to the polymerization product is 1:4 to 6.25, preferably 1:4 to 6.

[0023] According to the present invention, in step (4), the atmosphere for the carbonization reaction is an inert atmosphere. The inert atmosphere is an inert protective gas that serves to protect the reaction. Further, the inert atmosphere includes at least one of nitrogen and rare gases, preferably nitrogen.

[0024] According to the present invention, in step (4), the reaction conditions of the carbonization reaction are: the reaction pressure is 0.3MPa to 4.0MPa, preferably 0.3MPa to 3.5MPa; the reaction temperature is 380℃ to 480℃, preferably 385℃ to 430℃; and the reaction time is 4h to 6.5h, preferably 5h to 6h.

[0025] According to the present invention, in step (4), the impregnated bitumen has, by mass, a quinoline insoluble content (QI) of <0.02wt%, a toluene insoluble content (TI) of 15wt% to 18wt%, a β-resin content (i.e., TI-QI) of 15wt% to 18wt%, a coking value of 56wt% to 64wt%, a softening point of 80℃ to 95℃, an ash content of ≤0.015wt%, and a moisture content of ≤0.2wt%.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] This invention refines catalytic oil slurry, reducing the content of quinoline insolubles, ash, heteroatoms, and moisture, resulting in higher quality impregnated asphalt. The refined oil slurry is then subjected to vacuum distillation, separating the reaction products into light and heavy distillate oils. This classification of aromatic components ensures more efficient utilization of the catalytic oil slurry fractions. The heavy distillate oil is rich in polycyclic aromatic hydrocarbons (PAHs), while the light distillate oil is rich in monocyclic and bicyclic PAHs. The polymer obtained from the thermal polymerization of the heavy distillate oil is then carbonized with the light distillate oil. On the one hand, the addition of an appropriate amount of light distillate oil lowers the softening point of the product; on the other hand, the polymer product rich in toluene-insoluble matter obtained by the thermal polymerization reaction of light and heavy distillate oils undergoes a co-carbonization thermal condensation reaction. The reaction system contains numerous cycloalkanes and long alkyl side chains, resulting in lower viscosity during layer stacking. This structure determines superior high-temperature rheological properties of the product, enabling the impregnated bitumen prepared in this invention to maintain good flowability when impregnating graphite, promoting the encapsulation and penetration of the impregnated bitumen into the impregnated graphite. This invention achieves a reduction in the softening point and optimization of high-temperature fluidity.

[0028] This invention utilizes a process of "component regulation + polycyclic aromatic hydrocarbon thermal polymerization + light component reprocessing" to increase the toluene-insoluble content in the polymerization product. Toluene-insoluble matter can be produced by the polymerization of tricyclic, tetracyclic, and pentacyclic aromatic hydrocarbons. By enriching and polymerizing polycyclic aromatic hydrocarbons and simultaneously reprocessing the light products generated from polycyclic aromatic hydrocarbon polymerization back into the reaction system, the toluene-insoluble content is significantly increased, which is beneficial for improving product quality. Detailed Implementation

[0029] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention.

[0030] The main properties of the catalytic cracking slurry feedstock used in the embodiments and comparative examples of this invention are shown in Table 1.

[0031] Table 1 Properties of Catalytic Cracking Slurry Feedstock

[0032]

[0033]

[0034] Table 2. Properties of the hydrogenation protectants used in the examples and comparative examples.

[0035]

[0036] Table 3. Properties of the hydrorefining catalysts used in the examples and comparative examples.

[0037]

[0038] Example 1

[0039] (1) The catalytic slurry undergoes a hydrorefining reaction in a fixed-bed reactor to obtain the hydrorefined product. The reactor is loaded with hydroprotectant FZC-103A and hydrorefining catalyst FZC-301A sequentially. The volume ratio of hydroprotectant to hydrorefining catalyst is 1:5. The reaction conditions in the hydrorefining reaction zone are: reaction temperature 360℃, hydrogen partial pressure 5.0MPa, hydrogen-to-oil volume ratio 1400, and liquid hourly space velocity 0.3h⁻¹. -1 .

[0040] (2) The hydrorefined product is fractionated to obtain light distillate and heavy distillate. The 95% distillate of the light distillate has a distillation point of 420°C and a sulfur content of 0.74 wt%. The 5% distillate of the heavy distillate has a distillation point of 415°C and a sulfur content of 1.20 wt%.

[0041] In the hydrocarbon composition distribution of the heavy distillate oil, the mass percentage of 3- to 5-ring aromatics is 67.3 wt%, the content of quinoline insolubles is 0.005 wt%, and the content of toluene insolubles is 7.25 wt%. In the hydrocarbon composition distribution of the light distillate oil, the mass percentage of monocyclic and bicyclic aromatics is 21.7 wt%, the content of quinoline insolubles is 0.007 wt%, and the content of toluene insolubles is 8.68 wt%.

[0042] (3) The heavy distillate oil obtained in step (2) was placed in a reactor equipped with a reflux distillation device and subjected to thermal polymerization at 2.0 MPa and 380 °C for 7 h. At the same time, the light distillate that was flash distilled was refluxed back into the polymerization reaction system. The reflux ratio was 12 wt%. The polymerization product was obtained.

[0043] (4) The polymer product obtained in step (3) and the light distillate oil obtained in step (2) are co-carbonized at a mass ratio of 6:1 under nitrogen protection at 1.5 MPa and 415 °C for 5.5 h to obtain impregnated asphalt.

[0044] The impregnated bitumen contains, by mass, 0.011 wt% quinoline insolubles (QI), 17.65 wt% toluene insolubles (TI), 17.64 wt% β-resin, 62.8 wt% coking value, 91°C softening point, 0.008 wt% ash, and 0.13 wt% moisture.

[0045] Example 2

[0046] (1) The catalytic slurry undergoes a hydrorefining reaction in a fixed-bed reactor to obtain the hydrorefined product. The reactor is loaded with hydroprotectant FZC-103A and hydrorefining catalyst FZC-301A sequentially. The volume ratio of hydroprotectant to hydrorefining catalyst is 1:3. The reaction conditions in the hydrorefining reaction zone are: reaction temperature 290℃, hydrogen partial pressure 4.0MPa, hydrogen-to-oil volume ratio 1400, and liquid hourly space velocity 0.3h⁻¹. -1 .

[0047] (2) The hydrorefined product is fractionated to obtain light distillate and heavy distillate. The 95% distillate of the light distillate has a distillation point of 410℃ and a sulfur content of 0.80 wt%. The 5% distillate of the heavy distillate has a distillation point of 410℃ and a sulfur content of 1.02 wt%.

[0048] In the hydrocarbon composition distribution of the heavy distillate oil, the mass percentage of 3- to 5-ring aromatics is 59.6 wt%, the content of quinoline insolubles is 0.005 wt%, and the content of toluene insolubles is 9.05 wt%. In the hydrocarbon composition distribution of the light distillate oil, the mass percentage of monocyclic and bicyclic aromatics is 28.6 wt%, the content of quinoline insolubles is 0.014 wt%, and the content of toluene insolubles is 9.78 wt%.

[0049] (3) The heavy distillate oil obtained in step (2) was placed in a reactor equipped with a reflux distillation device and subjected to thermal polymerization at 1.8 MPa and 360 °C for 7 h. At the same time, the light distillate that was flash distilled was refluxed back into the polymerization reaction system. The reflux ratio was 11 wt%. The polymerization product was obtained.

[0050] (4) The polymer product obtained in step (3) and the light distillate oil obtained in step (1) are co-carbonized at 1.5 MPa and 405 °C for 6 h under nitrogen protection in a mass ratio of 7:1 to obtain impregnated asphalt.

[0051] The impregnated bitumen contains, by mass, 0.019 wt% quinoline insolubles (QI), 16.35 wt% toluene insolubles (TI), 16.33 wt% β-resin, 60.4 wt% coking value, 89 °C softening point, 0.014 wt% ash, and 0.18 wt% moisture.

[0052] Example 3

[0053] (1) The catalytic slurry undergoes a hydrorefining reaction in a fixed-bed reactor to obtain the hydrorefined product. The reactor is loaded with hydroprotectant FZC-103A and hydrorefining catalyst FZC-301A sequentially. The volume ratio of hydroprotectant to hydrorefining catalyst is 1:4. The reaction conditions in the hydrorefining reaction zone are: reaction temperature 350℃, hydrogen partial pressure 3.0MPa, hydrogen-to-oil volume ratio 1400, and liquid hourly space velocity 0.3h⁻¹. -1 .

[0054] (2) The hydrorefined product is fractionated to obtain light distillate and heavy distillate. The 95% distillate of the light distillate has a distillation point of 425°C and a sulfur content of 0.72 wt%. The 5% distillate of the heavy distillate has a distillation point of 415°C and a sulfur content of 1.13 wt%.

[0055] In the hydrocarbon composition distribution of the heavy distillate oil, the mass percentage of 3- to 5-ring aromatics is 65.6 wt%, the quinoline insoluble content is 0.004 wt%, and the toluene insoluble content is 6.62 wt%. In the hydrocarbon composition distribution of the light distillate oil, the mass percentage of monocyclic and bicyclic aromatics is 21.1 wt%, the quinoline insoluble content is 0.007 wt%, and the toluene insoluble content is 7.94 wt%.

[0056] (3) The heavy distillate oil obtained in step (2) is placed in a reactor equipped with a reflux distillation device and subjected to thermal polymerization at 1.2 MPa and 385 °C for 5.5 h. At the same time, the light distillate that has been flash-distilled is refluxed back into the polymerization reaction system. The reflux ratio is 10 wt%. The polymerization product is obtained.

[0057] (4) The polymer product obtained in step (3) and the light distillate oil obtained in step (2) are co-carbonized at a mass ratio of 5:1 under nitrogen protection at 1.0 MPa and 415 °C for 5 h to obtain impregnated asphalt.

[0058] The impregnated bitumen contains, by mass, 0.011 wt% quinoline insolubles (QI), 15.44 wt% toluene insolubles (TI), 15.43 wt% β-resin, 56 wt% coking value, 87°C softening point, 0.007 wt% ash, and 0.10 wt% moisture.

[0059] Example 4

[0060] (1) The catalytic slurry undergoes a hydrorefining reaction in a fixed-bed reactor to obtain the hydrorefined product. The reactor is loaded with hydroprotectant FZC-103A and hydrorefining catalyst FZC-301A sequentially. The volume ratio of hydroprotectant to hydrorefining catalyst is 1:3. The reaction conditions in the hydrorefining reaction zone are: reaction temperature 300℃, hydrogen partial pressure 3.0MPa, hydrogen-to-oil volume ratio 1400, and liquid hourly space velocity 0.3h⁻¹. -1 .

[0061] (2) The hydrorefined product is fractionated to obtain light distillate and heavy distillate. The 95% distillate of the light distillate has a distillation point of 430°C and a sulfur content of 0.68 wt%. The 5% distillate of the heavy distillate has a distillation point of 425°C and a sulfur content of 1.08 wt%.

[0062] In the hydrocarbon composition distribution of the heavy distillate oil, the mass percentage of 3-5 ring aromatics is 63.2 wt%, the quinoline insoluble content is 0.005 wt%, and the toluene insoluble content is 7.82 wt%; in the hydrocarbon composition distribution of the light distillate oil, the mass percentage of monocyclic and bicyclic aromatics is 18.9 wt%, the quinoline insoluble content is 0.009 wt%, and the toluene insoluble content is 8.95 wt%.

[0063] (3) The heavy distillate oil obtained in step (2) was placed in a reactor equipped with a reflux distillation device and subjected to thermal polymerization at 2.0 MPa and 350 °C for 6 h. At the same time, the light distillate that was flash distilled was refluxed back into the polymerization reaction system. The reflux ratio was 11 wt%. The polymerization product was obtained.

[0064] (4) The polymer product obtained in step (3) and the light distillate oil obtained in step (2) are co-carbonized at a mass ratio of 6:1 under nitrogen protection at 0.7 MPa and 390 °C for 5.5 h to obtain impregnated asphalt.

[0065] The impregnated bitumen contains, by mass, 0.013 wt% quinoline insolubles (QI), 16.13 wt% toluene insolubles (TI), 16.12 wt% β-resin, 56 wt% coking value, 91°C softening point, 0.008 wt% ash, and 0.14 wt% moisture.

[0066] Comparative Example 1

[0067] Steps (1), (2), and (4) in this example are the same as in Example 1. The only difference from Example 1 is that in step (3), when the polymerization reaction occurs in this example, a light distillate will flash out of the system, and the light distillate will not reflux. Everything else is the same as in Example 1.

[0068] In this example, the impregnated bitumen contained, by mass, 0.016 wt% quinoline insolubles (QI), 9.87 wt% toluene insolubles (TI), 9.86 wt% β-resin, 60.8 wt% coking value, 103 °C softening point, 0.009 wt% ash, and 0.14 wt% moisture.

[0069] Comparative Example 2

[0070] (1) The catalytic slurry undergoes a hydrorefining reaction in a fixed-bed reactor to obtain the hydrorefined product. The reactor is loaded with hydroprotectant FZC-103A and hydrorefining catalyst FZC-301A sequentially. The volume ratio of hydroprotectant to hydrorefining catalyst is 1:5. The reaction conditions in the hydrorefining reaction zone are: reaction temperature 360℃, hydrogen partial pressure 5.0MPa, hydrogen-to-oil volume ratio 1400, and liquid hourly space velocity 0.3h⁻¹. -1 .

[0071] (2) Hydrogenated oil slurry is obtained by separation of the hydrogenated refining product.

[0072] In the hydrocarbon composition distribution of the hydrogenated slurry, the mass percentage of 3-5 ring aromatics is 58.6 wt%, the mass percentage of mono- and bi-ring aromatics is 18.75 wt%, the content of quinoline insolubles is 0.011 wt%, and the content of toluene insolubles is 8.63 wt%.

[0073] (3) The hydrogenated slurry in step (2) is carbonized for 5.5 h under nitrogen protection at 1.5 MPa and 415 °C to obtain impregnated asphalt.

[0074] The impregnated bitumen contains, by mass, 0.024 wt% quinoline insolubles (QI), 10.61 wt% toluene insolubles (TI), 14.85 wt% β-resin, 54.8 wt% coking value, 99 °C softening point, 0.016 wt% ash, and 0.23 wt% moisture.

[0075] The specific embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for producing impregnating bitumen for graphite electrodes, comprising: (1) The catalytic slurry is hydrotreated to obtain the hydrotreated product; (2) The hydrorefined product obtained in step (1) is subjected to vacuum distillation to obtain light distillate oil and heavy distillate oil; (3) The heavy distillate oil obtained in step (2) is subjected to thermal polymerization reaction, and the light distillate that is flashed is refluxed to the polymerization reaction system to obtain the polymerization product. (4) The polymer product obtained in step (3) is carbonized with the light distillate oil obtained in step (2) to obtain impregnated asphalt.

2. The method according to claim 1, characterized in that, The catalytic slurry described in step (1) has a 5% distillation temperature of 280℃~380℃, preferably 300℃~350℃, and a 95% distillation temperature of 510℃~600℃, preferably 530℃~590℃; an aromatic carbon content of 30wt%~90wt%, preferably 50wt%~80wt%; an ash content of <0.07wt%, preferably <0.06%; and a sulfur content of 0.85wt%~1.20wt%.

3. The method according to claim 1, characterized in that, The reaction conditions for the hydrorefining reaction in step (1) are as follows: reaction temperature is 250℃~420℃, preferably 280℃~360℃; hydrogen partial pressure is 1MPa~10MPa, preferably 2MPa~5MPa; hydrogen-to-oil volume ratio is 500~1500, preferably 700~1400; and liquid hourly space velocity is 0.1h. -1 ~1.2h -1 Preferably 0.2h -1 ~0.9h -1 .

4. The method according to claim 1, characterized in that, The light distillate oil in step (2) has a distillation point temperature of 390℃~430℃ and a sulfur content of 0.65wt%~0.90wt% for 95% of its distillate; and a heavy distillate oil has a distillation point temperature of 410℃~440℃ and a sulfur content of 0.75wt%~1.20wt% for 5% of its distillate.

5. The method according to claim 1 or 4, characterized in that, In step (2), the hydrocarbon composition of the heavy distillate oil contains 58.7 wt% to 67.3 wt% of 3- to 5-ring aromatics; and / or, in step (2), the hydrocarbon composition of the light distillate oil contains 18.9 wt% to 28.6 wt% of mono- and bi-ring aromatics.

6. The method according to claim 1, characterized in that, The conditions for the thermal polymerization reaction in step (3) are: reaction pressure of 0.5MPa to 2.0MPa, preferably 1.2MPa to 2.0MPa; reaction temperature of 340℃ to 460℃, preferably 350℃ to 385℃; and reaction time of 4h to 8h, preferably 5.5h to 7h.

7. The method according to claim 1 or 6, characterized in that, When the polymerization reaction occurs in step (3), the system flash distills out light fractions; the light fractions are refluxed back into the polymerization reaction system; the remixing ratio is 8wt% to 15wt%, preferably 10wt% to 12wt%, by mass.

8. The method according to claim 1, characterized in that, In step (4), the mass ratio of light distillate oil to polymer product is 1:4 to 6.25, preferably 1:4 to 6.

9. The method according to claim 1, characterized in that, In step (4), the atmosphere of the carbonization reaction is an inert atmosphere; the reaction conditions of the carbonization reaction are: reaction pressure of 0.3MPa~4.0MPa, preferably 0.3MPa~3.5MPa; reaction temperature of 380℃~480℃, preferably 385℃~430℃; reaction time of 4h~6.5h, preferably 5h~6h.

10. The method according to claim 1, characterized in that, In step (4), the impregnated bitumen has the following mass content: quinoline insoluble matter (QI) < 0.02 wt%, toluene insoluble matter (TI) 15 wt% to 18 wt%, β resin content (i.e., TI-QI) 15 wt% to 18 wt%, coking value 56 wt% to 64 wt%, softening point 80℃ to 95℃, ash content ≤ 0.015 wt%, and moisture content ≤ 0.2 wt%.

Images