A method for preparing high-end carbon material raw materials by supercritical extraction of oil slurry

Abstract

The present invention belongs to the field of high-end carbon materials in petrochemical industry, and specifically relates to a method for preparing high-end carbon material raw materials by supercritical extraction of oil slurry, and the specific preparation steps are: S1, the oil slurry is evenly mixed with a diluting solvent, and extracted in countercurrent contact with a main solvent in an asphalt extraction tower to obtain a by-product asphalt; S2, the raffinate phase is further extracted in an aromatic oil extraction tower to obtain aromatic oil; S3, the raffinate phase is further extracted in a supercritical light de-oiling tower to obtain a by-product alkane oil. In the extraction process of the present invention, isopentane is selected as an extraction solvent, and the extraction tower temperature and pressure are accurately controlled, and impurities such as asphaltene and ash in the asphalt are effectively stripped off, and 3-5-ring aromatics in the asphalt are extracted into aromatic oil, so that the asphalt yield is reduced to 6%-9%, and the yield of light and heavy oil is effectively improved. The needle coke obtained by the method of the present invention to obtain aromatic oil can reach the standard of Water Island X-grade coke.

Description

Technical Field

[0001] The present invention belongs to the field of high-end carbon materials in petrochemical industry, and in particular relates to a method for preparing high-end carbon material raw materials by supercritical extraction of oil slurry. Background Art

[0002] High-end carbon materials are materials with high strength, high stability, corrosion resistance and other characteristics. Due to its high electrical conductivity, thermal conductivity and tensile strength, it is widely used in aviation, aerospace, energy, automobile, electronics and other fields. Among them, high-quality oil-based needle coke is a kind of high-end carbon material. It has a metallic luster in appearance, and its structure has obvious needle-shaped texture. The length and width of the particles are relatively large, and the whole is fibrous. At the same time, it has many excellent physical and chemical properties, such as high purity, low ash content, good electrical and thermal conductivity, and excellent mechanical strength. These characteristics enable it to be used in ultra-high power graphite electrodes, lithium-ion battery negative electrode materials and isostatic graphite in the steelmaking industry.

[0003] At present, the domestic oil-based needle coke industry started late, and the product still needs to be improved in terms of stability, quality and use effect. Especially in some high-end application fields, such as graphite electrode joint coke, it still needs to rely on external imports. This not only increases the procurement cost of enterprises, but also restricts the development of related industries to a certain extent.

[0004] In the existing oil-based needle coke production process, the raw material pretreatment stage generally relies on the traditional process of vacuum decompression and furfural refining. Although this process can meet production needs to a certain extent, its inherent defects and limitations are becoming increasingly prominent. First of all, the process is relatively long and involves multiple complex operating steps and links, which undoubtedly increases the uncertainty and management difficulty in the production process. At the same time, due to the large number of equipment types required for the process, it not only leads to high investment costs, but also makes the entire production line occupy a large area, and the use of land resources is not efficient enough.

[0005] In addition, the vacuum plus furfural refining process has high energy consumption and relatively high processing costs. This is mainly because the process consumes a large amount of energy during operation, including electricity, steam, etc., and the process has obvious deficiencies in adjusting the content of aromatics in aromatic-rich oil. In the production process of oil-based needle coke, the development stage of the intermediate phase asphalt has extremely high requirements for the mother liquor environment, and the content of aromatics is one of the key factors affecting the mother liquor environment. However, the vacuum plus furfural refining process cannot effectively adjust the content of aromatics to meet the optimal mother liquor environment required for the production of high-quality needle coke, which undoubtedly limits the improvement of product quality and the optimization of production efficiency.

[0006] Therefore, it is necessary to provide a more efficient, energy-saving and environmentally friendly preparation process for needle coke raw materials, which can flexibly adjust the yield of asphalt and the content of aromatics in aromatic-rich oil to ensure the mother liquor environment required for the production of high-quality needle coke in the intermediate phase asphalt development stage. Summary of the invention

[0007] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a method for preparing high-end carbon material raw materials by supercritical extraction of oil slurry. The method for preparing high-end carbon material raw materials by supercritical extraction of oil slurry provided by the present invention meets multiple requirements such as desolidification of oil slurry, removal of heavy colloids and asphaltene, removal of metal impurities, removal of part of sulfur and nitrogen elements, and enrichment of aromatics through a process, which significantly reduces energy consumption and operating labor costs. At the same time, the yield of asphalt and the content of aromatics in aromatic-rich oil can be flexibly adjusted to ensure the mother liquor environment required for the production of high-quality needle coke in the mesophase asphalt development stage.

[0008] The technical solution of the present invention is:

[0009] A method for preparing a high-end carbon material raw material by supercritical extraction of oil slurry, wherein the raw material for preparing the high-end carbon material is aromatic oil obtained from oil slurry by supercritical extraction, and the specific preparation steps are as follows:

[0010] S1. Heat the slurry oil, mix it evenly with the dilution solvent, continue to heat it, and then enter it from the top of the asphalt extraction tower, and enter the main solvent from the bottom of the asphalt extraction tower, and the two phases are countercurrently contacted and extracted, and an extract containing aromatics and alkanes is obtained from the top of the tower, and the asphalt flowing out from the bottom is discharged into the asphalt collection tank;

[0011] S2, the extract containing aromatics and alkane oil obtained in step S1 enters the top of the aromatic oil extraction tower, continues extraction, obtains the extract containing alkane oil from the top of the tower, and the aromatic oil (heavy deoiling) obtained at the bottom is discharged into the aromatic oil collection tank;

[0012] S3, the extract containing alkane oil obtained in step S2 enters the top of the supercritical light de-oiling tower for supercritical extraction, and the alkane oil obtained from the bottom of the tower is discharged into the alkane oil (light de-oiling) collection tank, and the remaining solvent is obtained at the top and can be recycled.

[0013] Furthermore, in step S1, the dilution solvent and the main solvent are both C5 alkanes, preferably isopentane.

[0014] Furthermore, the purity of the isopentane is>75%.

[0015] Furthermore, in the step S1, the oil slurry is heated to 40-120°C, mixed evenly with the dilution solvent, and further heated to 130-160°C, and then enters from the top of the asphalt extraction tower, and then the main solvent enters from the bottom of the asphalt extraction tower.

[0016] Furthermore, in the step S1, the volume ratio of the oil slurry to the dilution solvent is 7-9:1; and the volume ratio of the main solvent to the dilution solvent is 7:1.

[0017] Furthermore, in the step S1, when countercurrent contact extraction is performed in the asphalt extraction tower, the temperature in the tower is 100-180° C. and the pressure is 4.0-5.0 Mpa.

[0018] In the prior art, n-butane is often used as the oil slurry extraction solvent. The asphalt yield of this method is relatively high. However, the inventors of the present application found in experiments that the solubility of carbon 5 is better than that of carbon 4. Using carbon 5 solvent as the extraction solvent can effectively reduce the asphalt yield and basically does not affect the quality of heavy oil and light oil products. Therefore, isopentane is used as the main solvent and dilution solvent for supercritical extraction in the present invention. First, in the pretreatment process of the oil slurry, the oil slurry is first diluted with isopentane, and the volume ratio of the oil slurry to the dilution solvent is 7-9:1, and the temperature, pressure and other parameters of the supercritical extraction in the asphalt extraction tower are accurately controlled. Under this condition, the solubility of isopentane is greatly improved, and most of the heavy aromatics and alkanes in the oil slurry can be dissolved. This step is crucial for the effective separation of subsequent components. The separation of asphalt and light and heavy components is achieved in the asphalt extraction tower, and the undissolved asphalt is discharged from the bottom of the tower into the asphalt collection tank, and the aromatics and alkanes are mixed with the solvent and enter the next aromatic oil extraction tower.

[0019] Furthermore, in step S2, when the extract containing aromatics and alkane oil is extracted in the aromatic oil extraction tower, the temperature in the tower is 160-230°C and the pressure is 4.0-5.0 Mpa. Under such temperature and pressure conditions, the solubility of isopentane deteriorates, and the heavier aromatic oil will be precipitated and discharged from the bottom of the tower into the aromatic oil collection tank, while the alkane oil is mixed with the solvent and enters the next supercritical light de-oiling tower.

[0020] Furthermore, in step S3, when the extract containing alkane oil is extracted in a supercritical light de-oiling tower, the temperature in the tower is 220-245°C and the pressure is 4.0-5.0 Mpa. Under such temperature, pressure and other conditions, isopentane is in a supercritical state, and the alkane oil will be separated. The alkane oil enters a collection tank from the bottom of the tower, and the solvent enters a recovery tank for recycling.

[0021] In addition, the present invention also provides an application of the aromatic oil separated by the above method in the preparation of high-end carbon materials, especially in the preparation of oil-based needle coke.

[0022] The present invention also provides a method for preparing oil-based needle coke, which adopts a conventional hydrodesulfurization process to control the sulfur content to ≤0.35wt% to obtain refined aromatic oil. The refined aromatic oil is placed in a coking pilot reactor, the reactor is maintained at 0.6 Mpa, heated to 410°C, and the internal heating furnace is heated at maximum load. After 410-430°C, the heating rate is controlled to be ≯10°C / h, and the temperature is increased at ≯5°C / h from 430-455°C. After reaching 455°C, the coke is stabilized for 10 hours. Then the temperature is increased to 470°C at a rate of 5°C / h. After stabilization at 470°C for 6 hours, the pressure is released to 0.1 Mpa, and then the temperature is increased to 500°C at a rate of 10°C / h. After reaching 500°C, the coke is maintained for 2 hours. After the raw coke is taken out, it is calcined at 1400°C for 3 hours to obtain needle coke.

[0023] The aromatics-rich oil separated and collected by the process of the present invention has low ash content, low asphaltene content, contains certain colloids, and has a 3-5 ring aromatic hydrocarbon content of more than 44%. It is the most ideal raw material for preparing needle coke, and the needle coke made through experiments can meet the standard of Water Island X-grade coke.

[0024] Compared with the prior art, the method for preparing high-end carbon material raw materials by supercritical extraction of oil slurry provided by the present invention has the following advantages:

[0025] (1) The present invention has changed the conventional extraction solvent in oil slurry extraction through a large number of creative experiments, and selected isopentane (purity>75%) as the extraction solvent, which has better solubility for asphalt and colloid. The different solubility of isopentane solvent on the components in the oil slurry is utilized to remove asphaltene, colloid and alkane in the oil slurry, while retaining the aromatic components for preparing high-end carbon materials, which are mainly 3-5 ring aromatic hydrocarbons.

[0026] (2) At the same time, the present invention also changes the extraction method. By adding a specific proportion of isopentane to the oil slurry for dilution and accurately controlling the temperature and pressure of the extraction tower, asphaltene, ash and other impurities in the asphalt are effectively stripped off, and 3-5-ring aromatic hydrocarbons in the asphalt are extracted into aromatic oil, which significantly reduces the asphalt yield. The asphalt yield of the device is reduced from the original 15%-22% (when the extractant is n-butane) to 6%-9%, effectively improving the yield of light and heavy oils, and the properties of the light and heavy oil products are not deteriorated. They can be used as raw materials for producing high-end carbon material needle coke. The needle coke obtained from aromatic oil using the method of the present invention can meet the standard of Water Island X-grade coke, thereby increasing the overall economic benefits of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the process flow of preparing high-end carbon material raw materials by supercritical extraction of oil slurry of the present invention;

[0028] Among them, 1 is an asphalt extraction tower, 2 is an aromatic oil extraction tower, 3 is a supercritical light de-oiling tower, 4 is an asphalt collecting tank, 5 is an aromatic oil collecting tank, 6 is an alkane oil collecting tank, 7 is an oil slurry and dilution solvent pipeline, 8 is a main solvent pipeline, and 9 is a solvent recovery pipeline.

[0029] Figure 2 Asphalt (a), aromatic oil (b), and alkane oil (c) separated in Example 2 of the present invention;

[0030] Figure 3 The needle coke is prepared by using the aromatic oil separated in Example 2 of the present invention as raw material. DETAILED DESCRIPTION

[0031] The present invention is further illustrated below through the description of specific implementation methods, but this is not a limitation of the present invention. Those skilled in the art can make various modifications or improvements based on the basic idea of ​​the present invention, but as long as they do not deviate from the basic idea of ​​the present invention, they are all within the protection scope of the present invention.

[0032] In the following examples and comparative examples, reagents not otherwise specified are conventional reagents and can be purchased from conventional reagent production and sales companies. The methods used are all prior art unless otherwise specified.

[0033] The method for preparing high-end carbon material raw materials by supercritical extraction of oil slurry provided by the present invention is to perform supercritical extraction on the oil slurry to obtain aromatic oil and other by-products, such as Figure 1 The figure is a schematic diagram of the process flow of the method for preparing high-end carbon material raw materials by supercritical extraction of oil slurry of the present invention, and the specific steps are as follows

[0034] S1, heating the slurry oil, mixing it with the dilution solvent, continuing to heat it, and then inputting it into the top of the asphalt extraction tower 1 through the slurry oil and dilution solvent pipeline 7, and the main solvent is pumped from the solvent pump into the bottom of the asphalt extraction tower 1 through the main solvent pipeline 8, and the two phases are countercurrently contacted and extracted, and an extract containing aromatics and alkanes is obtained from the top of the tower, and the asphalt flowing out from the bottom is discharged into the asphalt collection tank 4;

[0035] S2, the extract containing aromatics and alkane oil obtained in step S1 enters the top of the aromatic oil extraction tower 2, continues extraction, obtains the extract containing alkane oil from the top of the tower, and the aromatic oil obtained at the bottom is discharged into the aromatic oil collection tank 5;

[0036] S3, the extract containing alkane oil obtained in step S2 enters the top of the supercritical light de-oiling tower 3 for supercritical extraction, and the alkane oil obtained from the bottom of the tower is discharged into the alkane oil collecting tank 6, and the remaining solvent is recovered from the top. The remaining solvent separated in the asphalt collecting tank 4, the aromatic oil collecting tank 5, and the alkane oil collecting tank 6 is collected through the solvent recovery pipeline 9, and can be recycled after being treated by conventional processes.

[0037] Example 1

[0038] A method for preparing high-end carbon material raw materials by supercritical extraction of oil slurry, the specific preparation steps are as follows:

[0039] S1. Heat the slurry oil to 40°C, mix it evenly with the dilution solvent, continue to heat it to 130°C, and then enter it from the top of the asphalt extraction tower, and let the main solvent enter from the bottom of the asphalt extraction tower. Perform two-phase countercurrent contact extraction under the conditions of 100°C and 5.0 MPa in the tower, and obtain an extract containing aromatics and alkanes from the top of the tower, and discharge the asphalt flowing out from the bottom into the asphalt collection tank; the dilution solvent and the main solvent are both isopentane; the volume ratio of the slurry oil to the dilution solvent is 7:1; the volume ratio of the main solvent to the dilution solvent is 7:1;

[0040] S2, the extract containing aromatics and alkane oil obtained in step S1 enters the top of the aromatic oil extraction tower, and continues to extract at a temperature of 160° C. and a pressure of 5.0 MPa in the tower, obtaining an extract containing alkane oil from the top of the tower, and the aromatic oil obtained at the bottom is discharged into an aromatic oil collection tank;

[0041] S3, the extract containing alkane oil obtained in step S2 enters the top of the supercritical light de-oiling tower, and continues to perform supercritical extraction under the conditions of a temperature of 220° C. and a pressure of 5.0 Mpa in the tower, and the alkane oil obtained from the bottom of the tower is discharged into an alkane oil collection tank, and the remaining solvent is obtained at the top and can be recycled.

[0042] Through the above preparation steps, the raw material aromatic oil for preparing high-end carbon material needle coke, and the by-products asphalt and alkane oil in the process are obtained respectively.

[0043] Example 2

[0044] A method for preparing high-end carbon material raw materials by supercritical extraction of oil slurry, the specific preparation steps are as follows:

[0045] S1. Heat the slurry oil to 100°C, mix it with the dilution solvent, continue to heat it to 150°C, and then enter it from the top of the asphalt extraction tower, and let the main solvent enter from the bottom of the asphalt extraction tower. Perform two-phase countercurrent contact extraction under the conditions of 160°C and 4.5 MPa in the tower, and obtain an extract containing aromatics and alkanes from the top of the tower. The asphalt flowing out from the bottom is discharged into the asphalt collection tank; the dilution solvent and the main solvent are both isopentane; the volume ratio of the slurry oil to the dilution solvent is 8:1; the volume ratio of the main solvent to the dilution solvent is 7:1;

[0046] S2, the extract containing aromatics and alkane oil obtained in step S1 enters the top of the aromatic oil extraction tower, and continues to extract at a temperature of 200° C. and a pressure of 4.5 MPa in the tower, obtaining an extract containing alkane oil from the top of the tower, and the aromatic oil obtained at the bottom is discharged into an aromatic oil collection tank;

[0047] S3, the extract containing alkane oil obtained in step S2 enters the top of the supercritical light de-oiling tower, and continues to perform supercritical extraction under the conditions of a temperature of 230° C. and a pressure of 4.5 MPa in the tower, and the alkane oil obtained from the bottom of the tower is discharged into an alkane oil collection tank, and the remaining solvent is obtained at the top and can be recycled.

[0048] After the above preparation steps, the raw material aromatic oil for preparing high-end carbon material needle coke, as well as the by-products asphalt and alkane oil in the process are obtained respectively. The specific products are as follows Figure 2 As shown, a is asphalt, b is aromatic oil, and c is alkane oil.

[0049] Example 3

[0050] A method for preparing high-end carbon material raw materials by supercritical extraction of oil slurry, the specific preparation steps are as follows:

[0051] S1. Heat the slurry oil to 120°C, mix it evenly with the dilution solvent, continue to heat it to 160°C, and then enter it from the top of the asphalt extraction tower, and let the main solvent enter from the bottom of the asphalt extraction tower. Perform two-phase countercurrent contact extraction under the conditions of the temperature in the tower being 180°C and the pressure being 4.0 MPa. Obtain an extract containing aromatics and alkanes from the top of the tower, and discharge the asphalt flowing out from the bottom into an asphalt collection tank; the dilution solvent and the main solvent are both isopentane; the volume ratio of the slurry oil to the dilution solvent is 9:1; the volume ratio of the main solvent to the dilution solvent is 7:1;

[0052] S2, the extract containing aromatics and alkane oil obtained in step S1 enters the top of the aromatic oil extraction tower, and continues to extract at a temperature of 230° C. and a pressure of 4.0 MPa in the tower, obtaining an extract containing alkane oil from the top of the tower, and the aromatic oil obtained at the bottom is discharged into an aromatic oil collection tank;

[0053] S3, the extract containing alkane oil obtained in step S2 enters the top of the supercritical light de-oiling tower, and continues to perform supercritical extraction under the conditions of a temperature of 245° C. and a pressure of 4.0 Mpa in the tower, and the alkane oil obtained from the bottom of the tower is discharged into an alkane oil collection tank, and the remaining solvent is obtained at the top and can be recycled.

[0054] Through the above preparation steps, the raw material aromatic oil for preparing high-end carbon material needle coke, and the by-products asphalt and alkane oil in the process are obtained respectively.

[0055] Comparative Example 1

[0056] Compared with Example 2, the difference is that the dilution solvent and the main solvent in step S1 are both n-butane, and other parameters and operations are the same as those in Example 2.

[0057] Comparative Example 2

[0058] Compared with Example 2, the difference is that the dilution solvent and the main solvent in step S1 are both composed of a mixture of n-butane and isopentane, wherein n-butane is 90 wt% and isopentane is 10 wt%, and other parameters and operations are the same as those in Example 2.

[0059] Comparative Example 3

[0060] Compared with Example 2, the difference is that the dilution solvent and the main solvent in step S1 are both composed of a mixture of isopentane and n-butane, wherein isopentane is 90 wt% and n-butane is 10 wt%, and other parameters and operations are the same as those in Example 2.

[0061] Comparative Example 4

[0062] Compared with Example 2, the difference is that the extraction temperature in the control tower in step S1 is 90° C., and other parameters and operations are the same as those in Example 2.

[0063] Comparative Example 5

[0064] Compared with Example 2, the difference is that the extraction pressure in the control tower in step S1 is 3.0 Mpa, and other parameters and operations are the same as those in Example 2.

[0065] Comparative Example 6

[0066] Compared with Example 2, the difference is that no dilution solvent is added in step S1, that is, the oil slurry enters directly from the top of the asphalt extraction tower, and the main solvent isopentane enters from the bottom of the tower. The volume ratio of isopentane to oil slurry is 7:1, and other parameters and operations are the same as those in Example 2.

[0067] Test Example 1: Analysis of the Extraction and Separation Results of the Present Invention

[0068] 1. The yields (%) of asphalt, aromatic oil and alkane oil obtained in Examples 1 to 3 and Comparative Examples 1 to 6 were recorded respectively. The test results are shown in Table 1.

[0069] 2. The quality parameters and density of each component in the aromatic oil obtained in Examples 1 to 3 and Comparative Examples 1 to 6 were tested respectively. The experimental results are shown in Table 2.

[0070] Table 1

[0071] Group Alkane oil yield (%) Aromatic oil yield (%) Asphalt yield (%) Example 1 15.60 76.30 8.10 Example 2 15.40 76.70 7.90 Example 3 16.70 75.80 7.50 Comparative Example 1 9.90 75.10 15.00 Comparative Example 2 9.80 76.10 14.10 Comparative Example 3 16.00 74.40 9.60 Comparative Example 4 12.20 74.20 13.60 Comparative Example 5 13.30 75.20 11.50 Comparative Example 6 13.20 76.00 10.80

[0072] Table 2

[0073] Group Saturated content wt% Aroma wt% Colloid wt% Asphaltene wt% Bicyclic wt% Tricyclic wt% Four rings wt% Five rings wt% Density kg / m3 Ash wt% Example 1 11.40 72.58 16.00 0.02 10.05 19.30 23.65 2.00 1095.9 0.001 Example 2 12.23 73.28 14.45 0.04 9.23 17.80 25.17 2.90 1095.4 0.001 Example 3 10.72 71.47 17.81 0.01 9.10 14.00 25.80 4.25 1103.8 0.001 Comparative Example 1 15.76 72.11 12.13 0.01 9.00 13.65 27.75 5.00 1090.5 0.001 Comparative Example 2 14.84 71.89 13.26 0.01 7.80 18.20 26.50 1.40 1098.2 0.001 Comparative Example 3 12.76 73.10 14.13 0.01 9.23 17.80 25.17 2.90 1094.4 0.002 Comparative Example 4 16.70 72.14 11.15 0.01 7.83 12.33 25.93 6.27 1092.8 0.001 Comparative Example 5 13.52 71.24 15.23 0.01 8.00 11.67 26.87 5.10 1096.5 0.001 Comparative Example 6 13.17 71.27 15.55 0.01 10.20 16.22 25.27 3.90 1096.0 0.002

[0074] As shown in Table 1, the yields of asphalt, aromatic oil and alkane oil obtained by the methods of Examples 1 to 3 of the present invention do not change much. The average yield of asphalt in the groups of Examples 1 to 3 is 7.8%, the average yield of aromatic oil is 76.3%, and the average yield of alkane oil is 15.9%. As shown in Table 2, the aromatic oil separated in Examples 1 to 3 of the present invention has low ash content, low asphaltene, contains certain colloids, and the content of 3-5 ring aromatics is greater than 44%, wherein the average content of aromatics is 72.44 wt%, and the average content of saturated parts is relatively low, which is 11.45 wt%, and is the most ideal raw material for preparing needle coke.

[0075] When the types of dilution solvent and main solvent were changed in Comparative Examples 1, 2 and 3, it can be seen from Table 1 that the yield of asphalt in Comparative Examples 1 to 3 increased to varying degrees, while the contents of alkane oil and aromatic oil decreased to varying degrees.

[0076] When the extraction temperature in the asphalt extraction tower was reduced to 90°C in Comparative Example 4 and the extraction pressure in the asphalt extraction tower was reduced to 3.0 MPa in Comparative Example 5, the obtained asphalt yields were 13.6% and 11.5%, respectively, which were significantly higher than those in Examples 1 to 3 of the present invention.

[0077] In Comparative Example 6, the oil slurry entered the extraction tower without being diluted with a diluent solvent, and the asphalt yield was 10.8%, which was higher than the yield with a diluent solvent, indicating that the diluent solvent can fully mix the oil slurry and the solvent, which is beneficial to improving the extraction effect.

[0078] It can be seen that, under the experimental conditions of the method provided in Examples 1 to 3 of the present invention, with isopentane (purity>75%) as the extraction solvent, the volume ratio of slurry oil to dilution solvent being 7-9:1, the temperature of the asphalt extraction tower being 100-180°C, the aromatic oil extraction tower being 160-230°C, the temperature of the supercritical light deoiling tower being 220-245°C, and the reaction pressure being 4.0-5.0 Mpa, the aromatic oil yield is the highest, the aromatic content in the aromatic oil is 72.44wt%, and the alkane content is relatively low at 11.45wt%, which provides a very favorable mother liquor environment for the development and fusion of mesophase globules when producing needle coke, and is an indispensable step in the preparation of high-quality needle coke.

[0079] Test Example 2: Performance test of needle coke prepared using the aromatic oil obtained in Example 2 of the present invention as raw material

[0080] Test method:

[0081] The aromatic oil extracted from Example 2 of the present invention is refined by a conventional hydrodesulfurization process, the temperature of the hydrogenation unit is controlled at 300-340°C, the pressure is 3-6 MPa, and the Topsoe catalyst is used to control the sulfur content to ≤0.35wt%, and the refined aromatic oil is obtained. The refined aromatic oil is placed in a coking pilot reactor, the reactor is maintained at 0.6 Mpa, and the internal heating furnace is heated to 410°C to increase the temperature at maximum load. After 410-430°C, the heating rate is controlled to be ≯10°C / h, and the temperature is increased by ≯5°C / h at 430-455°C. After reaching 455°C, the coke is stabilized for 10 hours. Then the temperature is increased to 470°C at a rate of 5°C / h. After stabilization for 6 hours at 470°C, the pressure is released to 0.1 Mpa, and then the temperature is increased to 500°C at a rate of 10°C / h. After reaching 500°C, the coke is maintained for 2 hours. After the raw coke is taken out, it is calcined at 1400℃ for 3 hours to obtain needle coke. Figure 3 shown.

[0082] Table 3 is a comparison result of parameters of needle coke prepared by the present invention and water island needle coke.

[0083] Table 3

[0084] Test items Mizushima Needle Coke X Grade Needle coke prepared by the present invention True density (g / cm3) 2.13-2.15 2.146 Sulfur content (%) 0.25-0.35 0.34 Nitrogen content (%) 0.1-0.2 - Volatile matter (%) 0.05-0.15 0.3 Ash content (%) 0.05-0.10 0.02 Particle strength (%) - 26 CTE (room temperature - 600℃) 10-6 / ℃ 0.7-1.2 0.91

[0085] It can be seen from Table 3 that the performance of the needle coke prepared by using the aromatic oil separated by the method of Example 2 of the present invention as a raw material can reach the standard of Water Island X-grade coke.

[0086] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for preparing high-end carbon material raw materials by supercritical extraction of oil slurry, characterized in that: The raw material for preparing the high-end carbon material is aromatic oil obtained from oil slurry by supercritical extraction. The specific preparation steps are as follows: S1. Heat the slurry oil, mix it evenly with the dilution solvent, continue to heat it, and then enter it from the top of the asphalt extraction tower, and enter the main solvent from the bottom of the asphalt extraction tower, and the two phases are countercurrently contacted and extracted, and an extract containing aromatics and alkanes is obtained from the top of the tower, and the asphalt flowing out from the bottom is discharged into the asphalt collection tank; S2, the extract containing aromatics and alkanes obtained in step S1 enters the top of the aromatic oil extraction tower, continues extraction, obtains an extract containing alkanes oil from the top of the tower, and discharges the aromatic oil obtained at the bottom into an aromatic oil collection tank; S3, the alkane oil extract obtained in step S2 is fed into the top of the supercritical light de-oiling tower for supercritical extraction, the alkane oil obtained from the bottom of the tower is discharged into the alkane oil collection tank, and the remaining solvent is obtained from the top for recycling; The dilution solvent and the main solvent in step S1 are both isopentane, and the purity of isopentane is greater than 75%; In the step S1, the volume ratio of the oil slurry to the dilution solvent is 7-9:1, and the volume ratio of the main solvent to the dilution solvent is 7:1; In the step S1, when countercurrent contact extraction is performed in the asphalt extraction tower, the temperature in the tower is 100-180° C. and the pressure is 4.0-5.0 Mpa; In the step S2, when the extract containing aromatics and alkanes is extracted in the aromatic oil extraction tower, the temperature in the tower is 160-230° C. and the pressure is 4.0-5.0 Mpa; In the step S3, when the alkane oil extract is extracted in the supercritical light de-oiling tower, the temperature in the tower is 220-245° C. and the pressure is 4.0-5.0 Mpa.

2. The method for preparing high-end carbon material raw materials by supercritical extraction of oil slurry according to claim 1, characterized in that: In the step S1, the oil slurry is heated to 40-120°C, mixed evenly with the dilution solvent, and further heated to 130-160°C, and then enters from the top of the asphalt extraction tower, and then the main solvent enters from the bottom of the asphalt extraction tower.

3. Use of aromatic oil obtained by the method for preparing high-end carbon material raw materials by supercritical extraction of oil slurry according to any one of claims 1 to 2 in the preparation of high-end carbon materials.

4. The use according to claim 3, characterized in that: The high-end carbon material is oil-based needle coke.

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