Preparation method, device and application of ethylene tar-based coated asphalt

Abstract

The invention provides a preparation method of ethylene tar-based coated asphalt as well as a device and application thereof. The preparation method comprises the following steps: A) pretreating ethylene tar; b) preparing de-ashed coal tar pitch; c) mixing the raw materials: mixing the heavy component of the ethylene tar in the step A) and the de-ashed coal tar pitch in the step B) according to a mass ratio of (0.4-0.9): (0.1-0.6), controlling the reactivity index fa of the mixed pitch to be in a range of 0.72-0.8, and controlling the coking value of the mixed pitch to be 29%-38%; d) performing steam stripping pretreatment: performing steam stripping treatment on the mixed asphalt in the step C) in an inert gas atmosphere under the conditions that the steam stripping amount is 0.010-0.020 Nm < 3 > / kg, the temperature is 200-230 DEG C, the steam stripping time is 2-4 hours, and the rising range of the softening point is controlled to be 11.6-20 DEG C; and E) high-temperature polymerization reaction: introducing inert gas into the steam-stripped asphalt obtained in the step D) at 290-310 DEG C for continuous steam stripping, controlling the reaction time to be 15-30 hours, and controlling the rising range of the softening point to be 60-160 DEG C to obtain the ethylene tar-based coated asphalt with the coking value being greater than or equal to 60%.

Description

Technical Field

[0001] The present invention relates to the field of deep processing of asphalt, and particularly relates to a preparation method, a device and an application of ethylene tar-based coated asphalt. Background Art

[0002] Ethylene tar is a product of high-temperature condensation of raw materials and products during the steam cracking of ethylene cracking raw materials to produce ethylene. Its output and composition vary with different ethylene cracking raw materials and cracking conditions. In terms of its yield, it is generally 10%-15% of the ethylene output, and with the heavy quality of the ethylene cracking raw material supply, its yield will increase. The main components of the ethylene tar in the IBP-205°C distillation section are indene and its homologues, the 205-225°C distillation fraction is naphthalene, the 225-245°C distillation fraction is mainly methylnaphthalene, the 245-300°C distillation section is mainly dimethylnaphthalene, the 300-360°C distillation fraction contains a large amount of anthracene, acenaphthene, phenanthrene, etc., and the substances above 360°C are mainly gums and asphaltenes with a very high carbon-hydrogen ratio. Each distillation section of ethylene tar is an important raw material for fine chemicals, medicine, dyes, and organic synthesis. Many valuable chemical products can be extracted from it, and it has important development value. However, at present, for the utilization of ethylene tar in China, it is generally used as fuel for boilers or kilns, with low economic utilization value. Moreover, ethylene tar is a product of high-temperature condensation of ethylene raw materials, and its main components are aromatic compounds, with short side chains, high carbon-hydrogen ratio, low ash content, and very low heavy metal content. When used as fuel for boilers or cracking furnaces, due to the presence of heavy alkenyl aromatics, etc., it is easy to produce coke and black smoke during combustion, causing certain pollution to the environment. Therefore, for the large amount of by-product tar raw materials produced by the ethylene process, making full and reasonable use of this part of resources to generate the best economic benefits will have a significant impact on the overall benefits of the ethylene plant and the development of deep processing of ethylene by-products resources.

[0003] The anode material of lithium batteries is the carrier of lithium ions and electrons during the charging process of the battery, playing a role in energy storage and release. Among the costs of lithium batteries, the anode material accounts for about 5%-15%, which is one of the important raw materials for lithium-ion batteries. From 2018 to 2022, the market demand for lithium battery anode materials in China has increased steadily, with a growth rate of 347.8% in five years. It is estimated that in 2025, the demand for lithium battery anode materials in China will reach 2.217 million tons, and it is expected to reach 8.308 million tons in 2030. However, due to its structural defects, poor compatibility with organic electrolytes, and easy occurrence of solvent co-insertion during charge and discharge in lithium battery anode materials, graphite layer peeling occurs, resulting in a decrease in its Coulomb efficiency and cycle performance. Coated pitch material is one of the most important products downstream of ethylene tar. Because it can surface-modify graphite anode materials, forming an amorphous carbon coating layer on the outer surface of the anode, it can improve the Coulomb efficiency and cycle performance of electrode materials, which is crucial for improving the performance of lithium-ion batteries and has now been widely used in lithium battery anode materials. Benefiting from the expansion of the domestic lithium battery industry, after 2017, both the production capacity and output of coated pitch in China have increased. The demand for coated pitch has increased at a growth rate of more than 30%. The demand reached 150,000 tons in 2022 and is expected to reach about 280,000 tons by 2025. The technology for preparing coated pitch from ethylene tar has great market promotion prospects. However, due to the complex production process of coated pitch and the high stability requirements of downstream anode materials for product quality, there are few domestic and foreign enterprises specializing in the production of coated pitch, and the production capacity of high-quality special coated pitch cannot meet the needs of domestic lithium-ion battery anode manufacturers. Due to this production status of coated pitch materials, most lithium-ion battery anode production enterprises use high-temperature coal tar pitch instead of coated pitch as raw materials. However, coal tar pitch has high ash content and high quinoline insoluble content, which seriously affect the service performance and life of lithium-ion batteries. Therefore, there is an urgent need to develop a new process for low-cost and high-quality coated pitch materials. Summary of the Invention

[0004] Aiming at the defects of the existing technology, the purpose of the present invention is to provide a preparation method, device and application of ethylene tar-based coated pitch.

[0005] The technical solution of the present invention is as follows: In the first aspect of the present invention, a preparation method of ethylene tar-based coated pitch is provided, including the following steps: A) Pretreat ethylene tar: Distill ethylene tar, intercept the heavy fraction after 250 °C, and control its softening point to be 110-130 °C and the coking value to be 25%-30%; B) Prepare deashed coal tar pitch: Perform deashing treatment on deashed coal liquefied pitch to obtain deashed coal tar pitch with a softening point of 85-110 °C and a coking value of 45%-53%; C) Raw material mixing: Recombinant fractions of ethylene tar after 250 °C in step A) and deashed coal tar pitch in step B) are mixed at a mass ratio of 0.4 - 0.9:0.1 - 0.6, controlling the reactivity index fa of the mixed pitch within the range of 0.72 - 0.8, and the coking value of the mixed pitch after mixing is 29% - 38%; D) Stripping pretreatment: The mixed pitch in step C) is subjected to stripping treatment in an inert gas atmosphere, with a stripping rate of 0.010 - 0.020 Nm 3 / kg, a temperature of 200 - 230 °C, and a stripping time of 2 - 4 hours, controlling the range of increase in softening point to be 11.6 - 20 °C; E) High-temperature polymerization reaction: The stripped pitch in step D) is continuously stripped by introducing an inert gas at 290 - 310 °C, controlling the reaction time to be 15 - 30 hours, and controlling the range of increase in softening point to be 60 - 160 °C, to obtain ethylene tar-based coated pitch with a coking value ≥ 60%.

[0006] Further, in step A), the recombinant fraction of ethylene tar after 250 °C has a softening point of 113 - 121 °C and a coking value of 26% - 27%.

[0007] Further, in step B), the deashed coal tar pitch has a softening point of 86 - 93 °C and a coking value of 47% - 49%.

[0008] Further, in step C), the reactivity index fa of the mixed pitch is controlled within the range of 0.77 - 0.78.

[0009] Further, in step E), the coking value of the ethylene tar-based coated pitch is 61% - 74%.

[0010] Further, the inert gas is N2.

[0011] In the second aspect of the present invention, an ethylene tar-based coated pitch is provided, and the coated pitch is obtained by the preparation method of the ethylene tar-based coated pitch described above.

[0012] In the third aspect of the present invention, a device used in the preparation method of the above ethylene tar-based coated pitch is provided. The device includes a distillation column, a mixer, a power device, an asphalt softening point conditioning kettle, a reactor A, and a reactor B. The distillation column is connected to the mixer; the mixer is connected to the power device, and the power device is respectively connected to the reactor A, the reactor B, and the forming cooler; in the mixer, the reactivity index fa of the mixed pitch is controlled within the range of 0.72 - 0.8.

[0013] Further, the mixer is a static mixer; the power device is a first external meshing gear pump, a second external meshing gear pump, and a third external meshing gear pump.

[0014] In the fourth aspect of the present invention, there is provided an application of the above ethylene tar-based coated asphalt in the preparation of a coated product for a negative electrode material.

[0015] Compared with the prior art, the present invention has the following beneficial effects: Domestic processes generally use methods such as oxidation or addition of initiators and crosslinking agents. These processes are complex, costly, relatively difficult to control during the reaction process, and have poor quality stability. The preparation method of the ethylene tar-based coated asphalt provided by the present invention does not add other crosslinking agents or initiators additionally. By using deashed coal liquefied asphalt as a restraint and copolymerization agent, the component distribution is adjusted, and a suitable polymerization temperature is selected to obtain a coated asphalt product with a higher softening point.

[0016] 2. In the preparation method of the ethylene tar-based coated asphalt provided by the present invention, by controlling the reaction index, the reaction time is adjusted using an external meshing gear pump. Based on the molecular similarity and solubility between coal liquefied asphalt and ethylene tar asphalt, and by applying the principle of similar phase solubility, the homogeneous regulation of components and the precise control of molecular weight distribution are achieved during the reaction process. This molecular-level design enables the finally obtained coated asphalt to not only have excellent quality stability, but also simultaneously achieve a synergistic improvement in softening point and coking value. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] By reading the following detailed description of non-limiting embodiments with reference to the accompanying drawings, other features, objectives, and advantages of the present invention will become more apparent: Figure 1 It is a schematic process flow diagram and a preparation device diagram of the ethylene tar-based coated asphalt provided by the present invention; Reference numerals: 1. Distillation column; 2. Mixer; 3. First external meshing gear pump; 4. Second external meshing gear pump; 5. Third external meshing gear pump; 6. Asphalt softening point blending kettle; 7. Reactor A; 8. Reactor B; 9. Molding cooler. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several changes and improvements can still be made, and these all fall within the protection scope of the present invention.

[0019] The present invention provides an ethylene tar-based coated asphalt and a preparation method thereof. The preparation process is as Figure 1 shown, and the preparation method includes the following steps: A) Pretreatment of ethylene tar: Ethylene cracking oil (PFO) is subjected to vacuum distillation to obtain ethylene tar. In distillation column 1, the ethylene tar is distilled, and the heavy fraction after 250 °C is intercepted, controlling its softening point to be 110 - 130 °C and the coking value to be 25% - 30%; further, preferably, the heavy fraction of ethylene tar after 250 °C with a softening point of 113 - 121 °C and a coking value of 26 - 27% is selected; B) Preparation of deashed coal tar pitch: Deashed coal liquefied pitch (sp 85 - 110 °C) is obtained by solvent sedimentation method and then removing the solvent by flash evaporation, and then the deashed coal liquefied pitch is deashed to obtain deashed coal tar pitch with a softening point (sp) of 85 - 110 °C and a coking value of 45% - 53%; further, preferably, deashed coal tar pitch with a softening point of 86 - 93 °C and a coking value of 47% - 49% is selected; C) Raw material mixing: The heavy fraction of ethylene tar in step A) and the deashed coal tar pitch in step B) are mixed in static mixer 2 according to a mass ratio of 0.4 - 0.9:0.1 - 0.6 to obtain a mixed pitch, controlling the reactivity index fa of the mixed pitch to be in the range of 0.72 - 0.8, and the coking value of the mixed pitch after mixing to be 29% - 38%; further, preferably, the reactivity index fa of the mixed pitch is controlled to be in the range of 0.77 - 0.78. The reactivity index fa is a raw material performance parameter, and the size of fa is controlled by the reaction temperature and reaction time; D) Stripping pretreatment: The mixed pitch in step C) is subjected to stripping treatment under an inert gas N2 atmosphere to obtain stripped pitch. In the pitch softening point blending kettle 6, the stripping amount of N2 is 0.010 - 0.020 Nm 3 / kg, set the reaction temperature to 200 - 230 °C, the stripping time to 2 - 4 hours, control the range of softening point increase to be 11.6 - 20 °C, and the softening point range of the stripped pitch to be 119 - 133.4 °C; E) High - temperature polymerization reaction: The stripped pitch in step D) is continuously stripped by introducing inert gas N2 in reactor A7 and / or reactor B8 at 290 - 310 °C, the stripping amount of N2 is 0.010 - 0.020 Nm 3 / kg, control the reaction time to be 15 - 30 hours, control the range of softening point increase to be 60 - 160 °C, to obtain ethylene - tar - based coated pitch with a coking value ≥ 60%, further, preferably, the coking value of the ethylene - tar - based coated pitch is 61% - 74%.

[0020] The present invention will be described in detail below in conjunction with specific embodiments.

[0021] First Embodiment As Figure 1As shown in the figure, this embodiment provides a device for preparing ethylene tar-based coated asphalt. In this embodiment, a static mixer 2 is selected as the mixer, and the first external meshing gear pump 3, the second external meshing gear pump 4, and the third external meshing gear pump 5 are used as the power devices of this embodiment to transport the product to the next reaction device. The device for preparing ethylene tar-based coated asphalt in this embodiment includes a distillation column 1, a static mixer 2, a first external meshing gear pump 3, a second external meshing gear pump 4, a third external meshing gear pump 5, an asphalt softening point blending kettle 6, a reactor A 7, a reactor B 8, a forming cooler 9, a wash oil tank, and a vacuum pump. The discharge port of the distillation column 1 is connected to the feed port of the static mixer 2; the discharge port of the static mixer 2 is connected to the feed port of the first external meshing gear pump 3, the discharge port of the first external meshing gear pump 3 is connected to the feed port of the reactor A 7, the discharge port of the reactor A 7 is connected to the second external meshing gear pump 4, the discharge port of the second external meshing gear pump 4 is connected to the feed port of the reactor B 8, the discharge port of the reactor B 8 is connected to the feed port of the third external meshing gear pump 5, and the discharge port of the third external meshing gear pump 5 is connected to the forming cooler 9. Ethylene tar and deashed coal tar pitch are mixed evenly by the static mixer 2, and the obtained mixture is transported to the asphalt softening point blending kettle 6 for stripping pretreatment. The stripping amount is set to 0.016 Nm 3 / kg. The stripped mixture (stripped asphalt) is transported to the reactor A 7 for high-temperature polymerization by the first external meshing gear pump 3. If the product is qualified, it can be directly transported to the forming cooler 9, cooled by cooling circulating water and bagged. If the product in the reactor A 7 does not meet the qualified standard, it needs to be transported to the reactor B 8 by the second external meshing gear pump 4. The reactor B 8 performs another high-temperature polymerization. After the product is qualified, it is transported to the forming cooler 9 by the third external meshing gear pump 5 for cooling and bagging. During the high-temperature polymerization reaction, the waste gas generated by the reactor A 7 and the reactor B 8 is discharged after being purified by the wash oil tank. Note: The judgment standard for whether the product is qualified can be determined according to whether the values of the softening point and coking value meet the requirements. In different application fields, the requirements for the softening point and coking value of the coated asphalt product are also different. Those skilled in the art can judge whether the product is qualified according to the actual situation. This embodiment does not make any limitations here.

[0022] Second Embodiment This embodiment provides an ethylene tar-based coated asphalt and a preparation method thereof. The preparation method of the ethylene tar-based coated asphalt in this embodiment is as follows: A) Pretreat ethylene tar: Ethylene tar is obtained by vacuum distillation of ethylene pyrolysis oil. In the distillation column 1, ethylene tar is distilled, and the heavy fraction after 250 °C is intercepted, and its softening point is controlled at 110 °C and the coking value is 25%; B) Preparation of deashed coal tar pitch: The deashed coal liquefied pitch is obtained by solvent sedimentation method and then removing the solvent by flash evaporation. Then, the deashed coal liquefied pitch is deashed to obtain deashed coal tar pitch with a softening point of 85°C and a coking value of 45%. C) Raw material mixing: The ethylene tar heavy fraction in step A) and the deashed coal tar pitch in step B) are mixed at a mass ratio of 0.4:0.1, controlling the reactivity index fa of the mixed pitch to be 0.72. The coking value of the mixed pitch is 29%, and the softening point of the mixed pitch is 105°C. D) Stripping pretreatment: The mixed pitch in step C) is stripped under N2, with a stripping rate of 0.016 Nm³ / kg, a temperature of 200°C, and a time of 3 hours. The softening point of the mixed pitch is increased to 123°C in the asphalt softening point blending kettle 6. E) High-temperature polymerization reaction: The stripped pitch in step D) is continuously stripped by introducing N2 at 290°C, controlling the reaction time to be 15 hours to obtain ethylene tar-based coated pitch with a softening point increased to 184°C and a coking value of 62%.

[0023] Softening point: When heated slowly, the sample softens in a standard softening point sample cup and the temperature at which it flows out 20 mm from the opening of the 6.35-mm sample cup. The softening point is applicable to substances that soften when heated but do not form a low-viscosity melt, such as tar pitch, hard pitch, asphalt, bitumen, and hot melt.

[0024] Measuring method of softening point: (1) Place four metal cups on the base, and then place the positioning disk and the funnel on top in turn.

[0025] (2) Load the sample into the funnel and then use a spatula to slide a small amount of the sample into the opening above the cup.

[0026] (3) Load enough sample into the cup until the filling height is flush with the upper edge.

[0027] (4) Use the round end of the tamper to firmly press the sample in.

[0028] (5) Rotate the positioning disk and repeat steps 1 - 4 for the other cups (all cups are partially filled).

[0029] (6) Place the funnel above the first cup again, and then use the flat end of the tamper to firmly press the sample in. There should be 1 mm of sample left above the upper edge.

[0030] (7) Rotate the positioning disk to the next cup and repeat step 6 for the other cups. When rotating the positioning disk, remove the excess sample.

[0031] (8) If you want to access the cup, rotate the funnel to the position between the cups and then press the spring.

[0032] (9) Remove the positioning disc and the funnel, fill the cup with the sample, and start the instrument for measuring the softening point of the coated asphalt (DP90 from Mettler) for measurement.

[0033] Coking value: A certain amount of sample is heated in a high-temperature furnace at 550 °C ± 10 °C under specified test conditions, and then the coke residue is weighed. The percentage of the coke residue amount to the sample amount is the coking value.

[0034] The measurement method of the coking value refers to GB / T 8727-2008: (1) Weigh 1 g ± 0.05 g (accurate to 0.0001 g) of the test sample, place it in a clean and pre-weighed 20 mL porcelain crucible, and cover the lid.

[0035] (2) Place the 20 mL crucible into a 100 mL crucible pre-lined with 10 mm ± 1 mm thick coke grains, and then fill the gap between the two crucibles with coke grains until the 20 mL crucible is completely buried. Cover the outer crucible with a lid.

[0036] (3) Place the loaded crucible on the crucible rack, and then put it into a high-temperature furnace at 550 °C ± 10 °C. Restore to a constant temperature within 10 min, otherwise the test fails.

[0037] (4) After two hours, take out the crucible from the furnace, cool it in the air for 5 min - 10 min, take out the inner crucible, put the inner crucible into a desiccator, cool it to room temperature, remove the attached coke powder, and weigh (accurate to 0.0001 g).

[0038] (5) Clean the 20 ml porcelain crucible and its lid, discard the residue, put it into a muffle furnace at 900 °C for calcination, remove the residue for standby.

[0039] (6) Calculate The coking value K of the sample = (M2 - M1) / M × 100%, where M2: the mass of the inner crucible and the residue; M1: the mass of the inner crucible; M: the mass of the test sample.

[0040] The third embodiment This embodiment provides an ethylene tar-based coated asphalt and its preparation method. The preparation method of the ethylene tar-based coated asphalt in this embodiment is as follows: A) Pretreat the ethylene tar: Ethylene tar is obtained by the atmospheric and vacuum distillation of ethylene cracking fuel oil. The ethylene tar is distilled, and the heavy fraction after 250 °C is intercepted, and its softening point is controlled at 130 °C and the coking value is 30%; B) Preparation of deashed coal tar pitch: The deashed coal liquefied pitch is obtained by solvent sedimentation method and then removing the solvent by flash evaporation. Then, the deashed coal liquefied pitch is deashed to obtain deashed coal tar pitch with a softening point of 110 °C and a coking value of 53%; C) Raw material mixing: The ethylene tar heavy fraction in step A) is mixed with the deashed coal tar pitch in step B) at a mass ratio of 0.9:0.6, and the reactivity index fa of the mixed pitch is controlled within 0.8. The coking value of the mixed pitch is 39.2%, and the softening point of the mixed pitch is 121.8 °C; D) Stripping pretreatment: The mixed pitch in step C) is subjected to stripping treatment in an inert gas atmosphere. The stripping amount is 0.016 Nm³ / kg, the temperature is 230 °C, and the time is 2 hours. The softening point of the mixed pitch is increased to 133.4 °C in the asphalt softening point blending kettle 6; E) High-temperature polymerization reaction: The stripped pitch in step D) is continuously stripped by introducing an inert gas at 310 °C, and the reaction time is controlled at 23 hours to obtain ethylene tar-based coated pitch with a softening point of 225.4 °C and a coking value of 72%.

[0041] Softening point: When heated slowly, the sample softens in a standard softening point sample cup and the temperature at which it flows out 20 mm from the 6.35 mm opening of the sample cup. The softening point is applicable to substances that soften when heated but do not form a low-viscosity melt. Such as tar pitch, hard asphalt, bitumen, tar, hot melt.

[0042] Measurement method of softening point: (1) Place four metal cups on the base, and then place the positioning disk and the funnel on top in turn.

[0043] (2) Load the sample into the funnel and then use a spatula to slide a small amount of the sample into the opening above the cup.

[0044] (3) Fill the cup with enough sample until the filling height is flush with the upper edge.

[0045] (4) Use the round end of the tamper to firmly press the sample into the cup.

[0046] (5) Rotate the positioning disk and repeat steps 1 - 4 for the other cups (all cups are partially filled).

[0047] (6) Place the funnel above the first cup again, and then use the flat end of the tamper to firmly press the sample into the cup. There should be 1 mm of sample left above the upper edge.

[0048] (7) Rotate the positioning disk to the next cup and repeat step 6 for the other cups. When rotating the positioning disk, remove the excess sample.

[0049] (8) If you want to touch the cup, turn the funnel to the position between the cups, and then press the spring.

[0050] (9) Remove the positioning plate and the funnel, fill the cup with the sample, and start the instrument for measuring the softening point of the coated pitch (DP90 of Mettler Company) for measurement.

[0051] Coking value: A certain amount of sample is placed in a high-temperature furnace at 550 °C ± 10 °C under specified test conditions and heated, and then the coke residue is weighed. The percentage of the coke residue amount to the sample amount is the coking value.

[0052] The measurement method of the coking value refers to GB / T 8727-2008: (1) Weigh 1 g ± 0.05 g (accurate to 0.0001 g) of the test sample, place it in a clean and pre-weighed 20 mL porcelain crucible, and cover the lid.

[0053] (2) Place the 20 mL crucible into a 100 mL crucible pre-laid with 10 mm ± 1 mm thick coke particles, and then fill the gap between the two crucibles with coke particles until the 20 mL crucible is completely buried, and cover the outer crucible with a lid.

[0054] (3) Place the loaded crucible on the crucible rack, and then put it into a high-temperature furnace at 550 °C ± 10 °C. Restore to a constant temperature within 10 minutes, otherwise the test fails.

[0055] (4) After two hours, take out the crucible from the furnace, cool it in the air for 5 min - 10 min, take out the inner crucible, put the inner crucible into a desiccator, cool it to room temperature, remove the attached coke powder, and weigh (accurate to 0.0001 g).

[0056] (5) Clean the 20 ml porcelain crucible and its lid, discard the residue, put it into a muffle furnace at 900 °C for calcination, remove the residue for standby.

[0057] (6) Calculate The coking value K of the sample = (M2 - M1) / M × 100%, where M2: the mass of the inner crucible and the residue; M1: the mass of the inner crucible; M: the mass of the test sample.

[0058] Fourth Embodiment This embodiment provides an ethylene tar-based coated pitch and its preparation method. The preparation method of the ethylene tar-based coated pitch in this embodiment is as follows: A) Pretreat the ethylene tar: Ethylene tar is obtained by the atmospheric and vacuum distillation of ethylene cracking fuel oil. The ethylene tar is distilled, and the heavy fraction distillate after 250 °C is intercepted, and its softening point is controlled at 121 °C and the coking value is 27%; B) Preparation of deashed coal tar pitch: Deashed coal liquefied pitch is obtained by solvent sedimentation method followed by flash evaporation to remove the solvent. Then, the deashed coal liquefied pitch is subjected to deashing treatment to obtain deashed coal tar pitch with a softening point of 86 °C and a coking value of 47%; C) Raw material mixing: The ethylene tar heavy fraction in step A) and the deashed coal tar pitch in step B) are mixed at a mass ratio of 0.55:0.5, and the reactivity index fa of the mixed pitch is controlled to be 0.78. The coking value of the mixed pitch is 38.3%; the softening point of the mixed pitch is 103 °C; D) Stripping pretreatment: The mixed pitch in step C) is subjected to stripping treatment in an inert gas atmosphere. The stripping amount is 0.016 Nm³ / kg, the temperature is 213 °C, and the time is 3 hours. The softening point of the mixed pitch is raised to 119 °C in the pitch softening point blending kettle 6; E) High-temperature polymerization reaction: The stripped pitch in step D) is continuously stripped by introducing N2 at 300 °C, and the reaction time is controlled to be 46 hours. Finally, ethylene tar-based coated pitch with a softening point of 246 °C and a coking value of 74% is obtained.

[0059] Softening point: When heated slowly, the temperature at which the sample softens in a standard softening point sample cup and flows out 20 mm from the 6.35-mm opening of the sample cup. The softening point is applicable to substances that soften when heated but do not form a low-viscosity melt. Such as tar pitch, hard pitch, asphalt, bitumen, hot melt.

[0060] Measurement method of softening point: (1) Place four metal cups on the base, and then place the positioning disk and the funnel on top in turn.

[0061] (2) Load the sample into the funnel and then use a spatula to slide a small amount of the sample into the opening above the cup.

[0062] (3) Load enough sample into the cup until the filling height is flush with the upper edge.

[0063] (4) Use the round end of the tamper to firmly press the sample into the cup.

[0064] (5) Rotate the positioning disk and repeat steps 1 - 4 for the other cups (all cups are partially filled).

[0065] (6) Place the funnel above the first cup again, and then use the flat end of the tamper to firmly press the sample into the cup. There should be a 1-mm sample left above the upper edge.

[0066] (7) Rotate the positioning disk to the next cup and repeat step 6 for the other cups. When rotating the positioning disk, remove the excess sample.

[0067] (8) If you need to access the cup, rotate the funnel to the position between the cups and then press the spring.

[0068] (9) Remove the positioning disk and the funnel, fill the cup with the sample, and start the instrument for measuring the softening point of the coated asphalt (DP90 of Mettler) for measurement.

[0069] Coking value: A certain amount of sample is heated in a high-temperature furnace at 550 °C ± 10 °C under specified test conditions, and then the coke residue is weighed. The percentage of the coke residue amount to the sample amount is the coking value.

[0070] The measuring method of the coking value refers to GB / T 8727-2008: (1) Weigh 1 g ± 0.05 g (accurate to 0.0001 g) of the test sample, place it in a clean and pre-weighed 20 mL porcelain crucible, and cover the lid.

[0071] (2) Place the 20 mL crucible into a 100 mL crucible pre-lined with 10 mm ± 1 mm thick coke particles, and then fill the gap between the two crucibles with coke particles until the 20 mL crucible is completely buried, and cover the outer crucible with a lid.

[0072] (3) Place the loaded crucible on the crucible rack, and then put it into a high-temperature furnace at 550 °C ± 10 °C. Restore to a constant temperature within 10 min, otherwise the test fails.

[0073] (4) After two hours, take out the crucible from the furnace, cool it in the air for 5 min - 10 min, take out the inner crucible, put the inner crucible into a desiccator, cool it to room temperature, remove the attached coke powder, and weigh (accurate to 0.0001 g).

[0074] (5) Clean the 20 ml porcelain crucible and its lid, discard the residue, put it into a muffle furnace at 900 °C for calcination, remove the residue for standby.

[0075] (6) Calculate The coking value K of the sample = (M2 - M1) / M × 100%, where M2: the mass of the inner crucible and the residue; M1: the mass of the inner crucible; M: the mass of the test sample.

[0076] The Fifth Embodiment This embodiment provides an ethylene tar-based coated asphalt and its preparation method. The preparation method of the ethylene tar-based coated asphalt in this embodiment is as follows: A) Pretreat the ethylene tar: Ethylene tar is obtained by the atmospheric and vacuum distillation of ethylene cracking fuel oil. The ethylene tar is distilled, and the heavy fraction after 250 °C is intercepted, and its softening point is controlled at 113 °C and the coking value is 30%; B) Preparation of deashed coal tar pitch: The deashed coal liquefied pitch is obtained by solvent sedimentation method and then removing the solvent by flash evaporation. Then, the deashed coal liquefied pitch is deashed to obtain deashed coal tar pitch with a softening point of 93 °C and a coking value of 49%; C) Raw material mixing: The heavy fraction of ethylene tar in step A) is mixed with the deashed coal tar pitch in step B) at a mass ratio of 0.45:0.1, and the reactivity index fa is controlled to be 0.77. The coking value of the mixed pitch is 33.5%; the softening point of the mixed pitch is 107 °C; D) Stripping pretreatment: The mixed pitch in step C) is stripped in an inert gas atmosphere. The stripping amount is 0.016 Nm 3 / kg, the temperature is 210 °C, and the time is 3 hours. The softening point of the mixed pitch is raised to 124 °C in the asphalt softening point blending kettle 6; E) High-temperature polymerization reaction: The stripped pitch in step D) is continuously stripped by introducing an inert gas at 305 °C, and the reaction time is controlled to be 28 hours. Finally, ethylene tar-based coated pitch with a softening point of 186 °C and a coking value of 61% is obtained.

[0077] Softening point: When heated slowly, the sample softens in a standard softening point sample cup and the temperature at which it flows out 20 mm from the 6.35-mm opening of the sample cup. The softening point is applicable to substances that soften when heated but do not form a low-viscosity melt. Such as tar pitch, hard pitch, asphalt, tar, hot melt.

[0078] Measurement method of softening point: (1) Place four metal cups on the base, and then place the positioning disk and the funnel on top in turn.

[0079] (2) Load the sample into the funnel and then use a spatula to slide a small amount of the sample into the opening above the cup.

[0080] (3) Fill the cup with enough sample until the filling height is flush with the upper edge.

[0081] (4) Use the round end of the tamper to firmly press the sample in.

[0082] (5) Rotate the positioning disk and repeat steps 1 - 4 for the other cups (all cups are partially filled).

[0083] (6) Place the funnel above the first cup again, and then use the flat end of the tamper to firmly press the sample in. There should be 1 mm of sample left above the upper edge.

[0084] (7) Rotate the positioning disk to the next cup and repeat step 6 for the other cups. When rotating the positioning disk, remove the excess sample.

[0085] (8)If you want to touch the cup, turn the funnel to the position between the cups, and then press the spring.

[0086] (9)Remove the positioning disk and the funnel, fill the cup with the sample, and start the instrument for measuring the softening point of the coated asphalt (DP90 of Mettler Company) for measurement.

[0087] Coking value: A certain amount of sample is heated in a high-temperature furnace at 550 °C ± 10 °C under specified test conditions, and then the coke residue is weighed. The percentage of the coke residue amount to the sample amount is the coking value.

[0088] The measurement method of the coking value refers to GB / T 8727-2008: (1)Weigh 1 g ± 0.05 g (accurate to 0.000 1 g) of the test sample, place it in a clean and pre-weighed 20 mL porcelain crucible, and cover the lid.

[0089] (2)Put the 20 mL crucible into a 100 mL crucible pre-lined with 10 mm ± 1 mm thick coke grains, and then fill the gap between the two crucibles with coke grains until the 20 mL crucible is completely buried, and cover the outer crucible with a lid.

[0090] (3)Place the loaded crucible on the crucible rack, and then put it into a high-temperature furnace at 550 °C ± 10 °C. Restore to a constant temperature within 10 min, otherwise the test fails.

[0091] (4)After two hours, take out the crucible from the furnace, cool it in the air for 5 min - 10 min, take out the inner crucible, put the inner crucible into a desiccator, cool it to room temperature, remove the attached coke powder, and weigh (accurate to 0.000 1 g).

[0092] (5)Clean the 20 ml porcelain crucible and its lid, discard the residue, put it into a muffle furnace at 900 °C for calcination, remove the residue for standby.

[0093] (6)Calculation The coking value K of the sample = (M2 - M1) / M × 100%, where M2: the mass of the inner crucible and the residue; M1: the mass of the inner crucible; M: the mass of the test sample.

[0094] Comparative example Through the following comparative examples, it is verified that the ethylene tar-based coated asphalt provided by the present invention has a higher softening point.

[0095] The preparation method of the ethylene tar-based coated asphalt in this comparative example is as follows: A) Pretreat ethylene tar: Ethylene tar is obtained by the atmospheric and vacuum distillation of ethylene cracking fuel oil. The ethylene tar is distilled, and the heavy fraction after 250 °C is intercepted, and its softening point is controlled at 126 °C and the coking value is 34%; B) Subject the ethylene tar heavy fraction in step A) to stripping treatment under an inert gas atmosphere, with a stripping amount of 0.016 Nm³ / kg, a temperature of 210 °C, and a time of 3 hours, and raise the softening point to 135 °C in the asphalt softening point blending kettle 6; C) High-temperature polymerization reaction: Continuously strip the stripped asphalt in step B) with N2 at 305 °C, control the reaction time to 36 hours, and finally obtain ethylene tar-based coated asphalt with a softening point of 196 °C and a coking value of 54%.

[0096] Softening point: When heated slowly, the sample softens in a standard softening point sample cup and the temperature at which it flows out 20 mm from the 6.35-mm opening of the sample cup. The softening point is applicable to substances that soften when heated but do not form a low-viscosity melt. Such as tar pitch, hard asphalt, asphalt, tar, hot melt.

[0097] Method for measuring the softening point: (1) Place four metal cups in the base, and then place the positioning disk and the funnel on top in sequence.

[0098] (2) Load the sample into the funnel and then use a spatula to slide a small amount of the sample into the opening above the cup.

[0099] (3) Fill the cup with a sufficient amount of the sample until the filling height is flush with the upper edge.

[0100] (4) Use the round end of the tamper to firmly press the sample in.

[0101] (5) Rotate the positioning disk and repeat steps 1 - 4 for the other cups (all cups are partially filled).

[0102] (6) Place the funnel above the first cup again, and then use the flat end of the tamper to firmly press the sample in. There should be 1 mm of the sample left above the upper edge.

[0103] (7) Rotate the positioning disk to the next cup and then repeat step 6 for the other cups. Remove the excess sample when rotating the positioning disk.

[0104] (8) If you want to access the cup, rotate the funnel to the position between the cups and then press the spring.

[0105] (9) Remove the positioning disk and the funnel, fill the cup with the sample, and start the instrument for measuring the softening point of the coated asphalt (DP90 from Mettler) for measurement.

[0106] Coking value: A certain amount of the sample is placed in a high-temperature furnace at 550 °C ± 10 °C under specified test conditions and heated, and then the coke residue is weighed. The percentage of the coke residue amount to the sample amount is the coking value.

[0107] The measurement method of coking value refers to GB / T 8727-2008: (1) Weigh 1 g ± 0.05 g of the sample (accurate to 0.0001 g), place it in a clean and pre-weighed 20 mL porcelain crucible, and cover the lid.

[0108] (2) Place the 20 mL crucible into a 100 mL crucible pre-lined with 10 mm ± 1 mm thick coke particles, and then fill the gap between the two crucibles with coke particles until the 20 mL crucible is completely buried. Cover the outer crucible with a lid.

[0109] (3) Place the loaded crucible on the crucible rack, and then put it into a high-temperature furnace at a temperature of 550 °C ± 10 °C. Restore to a constant temperature within 10 min, otherwise the test fails.

[0110] (4) After two hours, take out the crucible from the furnace, cool it in the air for 5 min - 10 min, take out the inner crucible, put the inner crucible into a dryer, cool it to room temperature, remove the attached coke powder, and weigh (accurate to 0.0001 g).

[0111] (5) Clean the 20 ml porcelain crucible and its lid, discard the residue, put it into a muffle furnace at 900 °C for burning, remove the residue for standby.

[0112] (6) Calculate The coking value K of the sample = (M2 - M1) / M × 100%, where M2 is the mass of the inner crucible and the residue; M1 is the mass of the inner crucible; M is the mass of the sample.

[0113] Compare the softening point and coking value of the coated pitch in the fourth embodiment and the fifth embodiment with those of the coated pitch in the comparative example. The fourth embodiment > the fifth embodiment > the comparative example, indicating that the preparation method provided by the present invention can effectively improve the thermal performance indexes (softening point and coking value) of the coated pitch.

[0114] The comparison results of the softening point and coking value of the coated pitch in the fourth embodiment and the fifth embodiment show that the softening point and the coking value are positively correlated. The higher the softening point, the higher the corresponding coking value.

[0115] The experimental results also show that when the softening points are similar, such as the fifth embodiment (softening point 186 °C) and the comparative example (softening point 196 °C), the coated pitch prepared by the method of the present invention (such as the fifth embodiment) has a higher coking value (61% > 54%) compared with the traditional method (comparative example). This indicates that when the softening points are at a similar level, the preparation method provided by the present invention can significantly improve the coking value of the coated pitch, which fully reflects the unique advantages of this preparation method in optimizing the material properties.

[0116] The core innovation of the preparation method provided by the present invention lies in the application of the principle of "like dissolves like". Through the molecular similarity between coal liquefaction pitch and ethylene tar pitch, the homogenization regulation of components and the precise control of molecular weight distribution are achieved during the reaction process. This molecular-level design enables the finally obtained coated pitch to not only have excellent quality stability, but also simultaneously realizes the synergistic improvement of softening point and coking value. This combination of properties makes this vinyl-coated pitch suitable for application scenarios with strict requirements for thermal properties, and particularly shows significant application advantages in the field of coating for lithium battery anode materials.

[0117] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. Without conflict, the embodiments of the present application and the features in the embodiments can be arbitrarily combined with each other.

Claims

1. A preparation method of ethylene tar-based coated asphalt, characterized in that, It includes the following steps: A) Pretreat the ethylene tar: Distill the ethylene tar, intercept the heavy fraction after 250 °C, and control its softening point to be 110 - 130 °C and the coking value to be 25% - 30%; B) Prepare deashed coal tar pitch: Conduct deashing treatment on deashed coal liquefaction pitch to obtain deashed coal tar pitch with a softening point of 85 - 110 °C and a coking value of 45% - 53%; C) Mix the raw materials: Mix the heavy fraction of ethylene tar in step A) with the deashed coal tar pitch in step B) according to a mass ratio of 0.4 - 0.9:0.1 - 0.6, control the reactivity index fa of the mixed pitch to be within the range of 0.72 - 0.8, and the coking value of the mixed pitch is 29% - 38%; D) Stripping pretreatment: The mixed asphalt from step C) is subjected to stripping treatment under an inert gas atmosphere, with a stripping amount of 0.010 - 0.020 Nm 3 / kg, a temperature of 200 - 230 °C, and a stripping time of 2 - 4 hours, controlling the softening point increase range to be 11.6 - 20 °C; E) High-temperature polymerization reaction: Continuously strip the stripped pitch in step D) with an inert gas at 290 - 310 °C, control the reaction time to be 15 - 30 hours, control the range of softening point increase to be 60 - 160 °C, and obtain ethylene tar-based coated pitch with a coking value ≥ 60%.

2. The preparation method of the ethylene tar-based coated asphalt according to claim 1, characterized in that, In step A), the heavy fraction of ethylene tar after 250 °C has a softening point of 113 - 121 °C and a coking value of 26 - 27%.

3. The preparation method of the ethylene tar-based coated asphalt according to claim 1, characterized in that, In step B), the deashed coal tar pitch has a softening point of 86 - 93 °C and a coking value of 47% - 49%.

4. The preparation method of the ethylene tar-based coated asphalt according to claim 1, characterized in that, In step C), control the reactivity index fa of the mixed pitch to be within the range of 0.77 - 0.

78.

5. The preparation method of the ethylene tar-based coated asphalt according to claim 1, characterized in that, In step E), the coking value of the ethylene tar-based coated pitch is 61% - 74%.

6. The preparation method of the ethylene tar-based coated asphalt according to claim 1, wherein The inert gas is N2.

7. An ethylene tar-based coated asphalt, characterized in that, The coated pitch is prepared by the preparation method of the ethylene tar-based coated pitch according to any one of claims 1 - 6.

8. An apparatus used in the preparation method of the ethylene tar-based coated asphalt according to any one of claims 1-6, characterized in that, The device includes a distillation column, a mixer, a power device, an asphalt softening point conditioning kettle, a reactor A, a reactor B, and a forming cooler. The distillation column is connected to the mixer; the mixer is connected to the power device, and the power device is respectively connected to the reactor A, the reactor B, and the forming cooler; in the mixer, control the reactivity index fa of the mixed pitch to be within the range of 0.72 - 0.

8.

9. The apparatus for preparing ethylene tar-based coated pitch according to claim 8, wherein The mixer is a static mixer; the power device is a first external meshing gear pump, a second external meshing gear pump, and a third external meshing gear pump.

10. Use of the ethylene tar-based coated pitch according to claim 7 in the preparation of a coated product for a negative electrode material.

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