Needle coke and preparation method therefor

Abstract

The present invention relates to the field of needle cokes. Disclosed are a needle coke and a preparation method therefor. The needle coke contains a reinforcing agent embedded between needle-shaped structures of the needle coke. The needle coke has a strength of 24-28%, a coefficient of thermal expansion of 0.9×10-6 / ºC to 1.1×10-6 / ºC, and an electrical conductivity of 1900 S / m-3000 S / m. The preparation method for the needle coke of the present invention comprises: (1) subjecting a coking raw material to a mesophase growth reaction to form mesophase spheres; and (2) subjecting the mesophase spheres to a drawing-coking reaction in a gas flow containing a reinforcing agent, wherein the mass ratio of the reinforcing agent to the coking raw material is 1:100-1:30000. The needle coke of the present invention has the advantages of higher strength, lower coefficient of thermal expansion, higher electrical conductivity, etc., and is suitable for application in materials such as metallurgical electrodes and battery electrodes.

Description

Needle coke and its preparation method

[0001] Cross-references to related applications

[0002] This application claims the benefit of Chinese Patent Application No. 202411647338.6, filed on November 18, 2024, the contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to the field of needle coke technology, and more specifically to a needle coke and its preparation method. Background Technology

[0004] Needle coke, as a high-quality carbon material, occupies an important position in this field due to its unique physical and chemical properties. With the rapid development of industrial technology, especially the increasing demands for electrode performance in steel smelting and electrolytic aluminum, the demand for graphite electrodes, particularly ultra-high power graphite electrodes, is growing rapidly. Ultra-high power graphite electrodes play an irreplaceable role in the smelting industry due to their high thermal shock resistance, high mechanical strength, excellent oxidation performance, low electrode consumption, and allowable high current density. Needle coke, as a key raw material for manufacturing ultra-high power graphite electrodes, directly affects the electrode's performance and lifespan.

[0005] Among the many performance indicators of needle coke, strength is a crucial parameter. The strength of needle coke not only affects its processing performance but also directly relates to its application in graphite electrodes. Lower needle coke strength can lead to cracks and fractures during manufacturing and use, severely impacting the integrity and performance of the electrode. Therefore, improving the strength of needle coke is of great significance for enhancing the performance of graphite electrodes and extending their service life.

[0006] Factors affecting the strength of needle coke include the size and density of the internal pores of the material, CTE (compound ester tract osmosis), composition of the coking feedstock, grain size and shape, and process conditions during preparation. Current research often improves strength by adjusting process conditions, such as thermal conversion temperature, pressure, residence time, and heating rate, which directly affect the condensation reaction and the formation of the mesophase, thus influencing the strength of the final needle coke. For example, Qi et al. (CN113698956A) proposed a production process to improve the pressure resistance of needle coke. By pretreating the coking feedstock, impurities were removed, increasing the purity of the feedstock. In the subsequent coking reaction, by optimizing parameters such as the circulation ratio of the circulating oil and the heating temperature, the coking tower was gradually heated, improving the pressure resistance of the needle coke. However, this method relies solely on process parameter control, resulting in limited improvement in strength.

[0007] In addition, there are studies that improve the strength of needle coke through post-processing. For example, Liao et al. (CN115745610A) made petroleum coke into micro powder, added graphene aqueous solution and dispersant for coating, and then calcined, impregnated and calcined the green blanks obtained by rolling and pressing, and then purified them at high temperature to obtain high-strength carbon-graphite materials. This method is complicated, requires multiple heating and has high cost. Summary of the Invention

[0008] The purpose of this invention is to solve the problems of low strength, poor conductivity and poor resistance to thermal expansion of existing needle coke, and to provide a needle coke and its preparation method. The needle coke of this invention has advantages such as higher strength, lower coefficient of thermal expansion and higher conductivity, and is suitable for use in materials such as metallurgical electrodes and battery electrodes.

[0009] To achieve the above objectives, the present invention provides a needle coke containing a reinforcing agent embedded between the needle-shaped structures of the needle coke. The needle coke has a strength of 24%-28% and a coefficient of thermal expansion of 0.9 × 10⁻⁶. -6 / ℃-1.1×10 -6 / ℃, with an electrical conductivity of 1900S / m-3000S / m.

[0010] The second aspect of the present invention provides a method for preparing needle coke, the method comprising: (1) forming mesophase spheres by a mesophase growth reaction of coking raw materials; (2) performing a coking-coking reaction of the mesophase spheres in a gas stream containing a reinforcing agent; wherein the mass ratio of the amount of the reinforcing agent to the amount of the coking raw materials is 1:100-1:30000.

[0011] A third aspect of the present invention provides needle coke prepared by the method of the present invention.

[0012] The beneficial effects of this invention are as follows:

[0013] First, increase the strength of needle coke:

[0014] The reinforcing agent is embedded between the needle-like structures of the needle coke, which can enhance the interaction force between the needle-like structure of the needle coke, the reinforcing agent, and the needle-like structure, thereby increasing the strength of the needle coke.

[0015] Second, reduce the coefficient of thermal expansion of needle coke:

[0016] The reinforcing agent is embedded between the needle-shaped structures of the needle coke, which can buffer the deformation of the needle coke when heated, so that the needle coke has a lower coefficient of thermal expansion.

[0017] Third, improve the electrical conductivity of needle coke:

[0018] The reinforcing agent is embedded between the needle-shaped structures of the needle coke, which not only improves the strength of the needle coke, but also enhances the conductivity between the needle-shaped structures, thereby enhancing the electrical conductivity of the needle coke.

[0019] Fourth, improve the thermal conductivity of needle coke:

[0020] The reinforcing agent is embedded between the needle-shaped structures of the needle coke, which also increases the heat exchange efficiency between the needle-shaped structures, thus resulting in a higher thermal conductivity. Attached Figure Description

[0021] Figure 1 is a schematic diagram of the technical route of the present invention;

[0022] Figure 2 is a flowchart of the apparatus for producing needle coke according to the present invention. Detailed Implementation

[0023] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0024] This invention provides a needle coke containing a reinforcing agent embedded between the needle-shaped structures of the needle coke. The needle coke has a strength of 24%-28% and a coefficient of thermal expansion of 0.9 × 10⁻⁶. -6 / ℃-1.1×10 -6 / ℃, with an electrical conductivity of 1900S / m-3000S / m.

[0025] According to a preferred embodiment of the present invention, the electrical conductivity of needle coke is 1900 S / m-2650 S / m. Using the aforementioned technical solution, needle coke has advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0026] According to a preferred embodiment of the present invention, the reinforcing agent content in the needle coke is 0.02wt%-1wt%. Using the aforementioned technical solution, the needle coke has advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0027] In this invention, needle coke with the aforementioned technical features can achieve the purpose of this invention. The range of possible methods for introducing the reinforcing agent is relatively wide. One embodiment is illustrated, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the reinforcing agent is introduced in situ during the coking process.

[0028] In this invention, the range of materials that can be selected for the reinforcing agent is relatively wide. One embodiment is illustrated, but this does not limit the scope of the invention. According to a preferred embodiment of the invention, the reinforcing agent includes one-dimensional carbon materials and / or two-dimensional carbon materials. Using the aforementioned technical solution, needle coke has advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0029] In this invention, the range of selectable dimensions for the reinforcing agent is relatively wide. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the equivalent diameter of the length or sheet size of the reinforcing agent along the axis or surface direction of the reinforcing agent is 0.2 μm to 200 μm.

[0030] According to a preferred embodiment of the present invention, the diameter or thickness of the reinforcing agent is 0.2 nm-15 μm in a direction perpendicular to the axis or plane of the reinforcing agent. Using the aforementioned technical solution, needle coke has advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0031] In this invention, commonly used one-dimensional carbon materials can achieve the objectives of the invention, and the range of types of one-dimensional carbon materials that can be selected is quite wide. One embodiment is illustrated, but this does not limit the scope of the invention. According to a preferred embodiment of the invention, the one-dimensional carbon material is selected from one or more of carbon nanotubes, carbon fibers, and graphite fibers. Using the aforementioned technical solution, needle coke has advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0032] In this invention, the range of selectable dimensions for the one-dimensional carbon material is relatively wide. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the length of the one-dimensional carbon material is 10 μm-150 μm along the axial direction of the one-dimensional carbon material.

[0033] According to a preferred embodiment of the present invention, the diameter of the one-dimensional carbon material is 1 nm-10 μm in a direction perpendicular to the axis of the one-dimensional carbon material. Using the aforementioned technical solution, needle coke has advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0034] In this invention, the one-dimensional carbon material uses carbon nanotubes and / or carbon fibers to illustrate the advantages of this invention. The carbon nanotubes are commercially available multi-walled carbon nanotubes with an outer diameter of 10nm-20nm and a length of 10μm-30μm; the carbon fibers are commercially available 24k carbon fibers, untreated, with a tensile modulus of 230GPa, a single filament diameter of 8μm, and pulverized, resulting in a single filament length of 100±20μm.

[0035] In this invention, a wide range of two-dimensional carbon materials can be selected. One embodiment is illustrated, but this does not limit the scope of the invention. According to a preferred embodiment of the invention, the two-dimensional carbon material is selected from graphene and / or graphite. Using the aforementioned technical solution, needle coke has advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0036] In this invention, the range of selectable dimensions for two-dimensional carbon materials is relatively wide. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the equivalent diameter of the sheet size of the two-dimensional carbon material is 20 μm-100 μm along the direction of the surface of the two-dimensional carbon material.

[0037] According to a preferred embodiment of the present invention, the two-dimensional carbon material has 1-30 carbon atom layers, such as 5, 10, 15, 20, and 25 layers. Those skilled in the art will understand that the thickness of a single carbon atom layer in a two-dimensional carbon material is approximately 0.34 nanometers. Using the aforementioned technical solution, needle coke exhibits advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0038] In this invention, the two-dimensional carbon material uses graphene and / or graphite to illustrate the advantages of this invention. Specifically, the graphene is prepared by graphite exfoliation, and the number of carbon atom layers in the graphene is: 1 layer (80%), 2 layers (20%), and the size of the graphene is 30±10 μm; the graphite is obtained by exfoliation, and the number of carbon atom layers is: 3-4 layers (60%), 5-6 layers (40%), and the size of the graphite is 50±10 μm.

[0039] According to a preferred embodiment of the present invention, the reinforcing agent comprises one-dimensional carbon material and two-dimensional carbon material, each with a content of not less than 10 wt%. By employing the aforementioned technical solution, the combined action of the one-dimensional carbon material and the two-dimensional carbon material can achieve multi-dimensional bonding forces between needle-shaped structures and construct a three-dimensional conductive network, thereby enabling the needle coke to possess advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0040] The second aspect of the present invention provides a method for preparing needle coke, the method comprising: (1) forming mesophase spheres by a mesophase growth reaction of coking raw materials; (2) performing a coking-coking reaction of the mesophase spheres in a gas stream containing a reinforcing agent; wherein the mass ratio of the amount of the reinforcing agent to the amount of the coking raw materials is 1:100-1:30000.

[0041] The method for preparing needle coke of the present invention introduces a reinforcing agent in situ during the coking-coking reaction, so that the reinforcing agent forms an oriented mosaic structure between the mesophase spherical structures. Moreover, this mosaic is combined in situ when the mesophase sphericals are transformed into needle coke, thereby realizing the in-situ strengthening of needle coke during the preparation process. The needle coke prepared has advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0042] In this invention, the method for preparing needle coke allows for a wide range of choices for the reinforcing agent. One embodiment is illustrated, but this does not limit the scope of the invention. According to a preferred embodiment, the reinforcing agent comprises one-dimensional carbon materials and / or two-dimensional carbon materials. Using the aforementioned technical solution, the prepared needle coke exhibits advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0043] In the preparation method of needle coke in this invention, the range of selectable sizes for the reinforcing agent is relatively wide. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, along the direction of the axis or surface of the reinforcing agent, the length or equivalent diameter of the lamellar size of the reinforcing agent is 0.2 μm-200 μm.

[0044] In the preparation method of needle coke according to this invention, in a preferred embodiment, the diameter or thickness of the reinforcing agent is 0.2 nm-15 μm in a direction perpendicular to the axis or plane of the reinforcing agent. Using the aforementioned technical solution, the prepared needle coke has advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0045] In this invention, the method for preparing needle coke allows for a wide range of one-dimensional carbon materials. One embodiment is illustrated, but this does not limit the scope of the invention. According to a preferred embodiment, the one-dimensional carbon material is selected from one or more of carbon nanotubes, carbon fibers, and graphite fibers. Using the aforementioned technical solution, the prepared needle coke exhibits advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0046] In this invention, the method for preparing needle coke allows for a wide range of selectable dimensions for the one-dimensional carbon material. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the length of the one-dimensional carbon material is 10 μm to 150 μm along the axial direction of the one-dimensional carbon material.

[0047] According to a preferred embodiment of the present invention, the diameter of the one-dimensional carbon material is 1 nm-10 μm in a direction perpendicular to the axis of the one-dimensional carbon material. Using the aforementioned technical solution, the prepared needle coke has advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0048] In this invention, the method for preparing needle coke uses carbon nanotubes and / or carbon fibers as the one-dimensional carbon material to illustrate the advantages of this invention. Specifically, the carbon nanotubes are commercially available multi-walled carbon nanotubes with an outer diameter of 10nm-20nm and a length of 10μm-30μm; the carbon fibers are commercially available 24k carbon fibers, untreated, with a tensile modulus of 230GPa, a single filament diameter of 8μm, and pulverized, resulting in a single filament length of 100±20μm.

[0049] In this invention, the preparation method of needle coke allows for a wide range of two-dimensional carbon materials. One embodiment is illustrated, but this does not limit the scope of the invention. According to a preferred embodiment of the invention, the two-dimensional carbon material is selected from graphene and / or graphite. Using the aforementioned technical solution, the prepared needle coke exhibits advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0050] In this invention, the method for preparing needle coke allows for a wide range of selectable dimensions for the two-dimensional carbon material. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the equivalent diameter of the sheet size of the two-dimensional carbon material is 20 μm-100 μm along the direction of the surface of the two-dimensional carbon material.

[0051] In this invention, in the method for preparing needle coke, according to a preferred embodiment of the invention, the number of carbon atom layers in the two-dimensional carbon material is 1-30, for example, 5, 10, 15, 20, and 25 layers. Those skilled in the art will understand that the thickness of a single carbon atom layer in a two-dimensional carbon material is approximately 0.34 nanometers. Using the aforementioned technical solution, the prepared needle coke exhibits advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0052] In this invention, the method for preparing needle coke uses graphene and / or graphite as the two-dimensional carbon material to illustrate the advantages of this invention. Specifically, the graphene is prepared by graphite exfoliation, and the number of carbon atom layers in the graphene is: 1 layer (80%), 2 layers (20%), and the size of the graphene is 30±10 μm; the graphite is obtained by exfoliation, and the number of carbon atom layers is: 3-4 layers (60%), 5-6 layers (40%), and the size of the graphite is 50±10 μm.

[0053] In the preparation method of needle coke according to this invention, in a preferred embodiment, the reinforcing agent comprises one-dimensional carbon material and two-dimensional carbon material, each with a content of not less than 10 wt%. Using the aforementioned technical solution, the combined action of one-dimensional and two-dimensional carbon materials can achieve multi-dimensional bonding forces between needle-shaped structures and construct a three-dimensional conductive network. The prepared needle coke exhibits advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0054] In this invention, the method for preparing needle coke involves a coking-coking reaction of mesophase spheres in a gas stream containing a reinforcing agent. There are no special requirements for the preparation method of the gas stream containing the reinforcing agent; any method known to those skilled in the art can be used to form the gas stream containing the reinforcing agent. For example, the reinforcing agent can be dispersed in a coking medium to form the gas stream containing the reinforcing agent. The coking medium is a readily vaporizable or gaseous substance used to generate the coking gas stream and participate in the coking-coking reaction. The range of sources and types of the coking medium is relatively wide. For example, the coking medium can come from the coking reaction system and / or be introduced from the outside. The coking medium can be selected from one or more of naphtha fraction, gasoline fraction, kerosene fraction, diesel fraction, wax oil fraction, gaseous hydrocarbons with 1 to 3 carbon atoms (methane, ethane, butane), inert gases (nitrogen, argon, carbon dioxide, etc.), and water (water vapor).

[0055] In the preparation method of needle coke in this invention, there are no special requirements for the dispersion method of the reinforcing agent in the coking medium to form the gas flow containing the reinforcing agent. This is an illustrative example, but it does not limit the scope of the invention. For example, the dispersion method can be one or more of vibration, stirring, and ultrasonic-assisted mixing. In actual operation, various stirrers can be used for mixing, and ultrasonic devices can be used to assist mixing so that the reinforcing agent is uniformly dispersed in the coking medium.

[0056] According to a preferred embodiment of the present invention, the coking medium includes at least two of naphtha fraction, diesel fraction, and wax oil fraction, wherein the content of any one of naphtha fraction, diesel fraction, or wax oil fraction in the coking medium is 4-96 wt%. The needle coke prepared using the aforementioned technical solution has advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0057] In this invention, the coking medium having the aforementioned composition can achieve the purpose of this invention in the preparation method of needle coke. There are no special requirements for the properties of coking media such as naphtha fraction, diesel fraction, and wax oil fraction. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the 5% distillation temperature of naphtha fraction is 40℃-70℃, and the 95% distillation temperature of naphtha fraction is 150℃-190℃.

[0058] In the preparation method of needle coke according to the present invention, in a preferred embodiment of the present invention, the 5% distillation temperature of the diesel fraction is 190℃-240℃, and the 95% distillation temperature of the diesel fraction is 300℃-350℃.

[0059] In the preparation method of needle coke according to the present invention, in a preferred embodiment of the present invention, the 5% distillation temperature of the wax oil fraction is 250℃-300℃, and the 95% distillation temperature of the wax oil fraction is 380℃-420℃.

[0060] In this invention, the coking medium possessing the aforementioned technical characteristics can achieve the purpose of this invention in the method for preparing needle coke. Those skilled in the art will understand that the coking medium from the coking reaction system is generally obtained by fractionation of coking reaction separation oil produced during the reaction process, including top gas, coking naphtha, coking diesel oil, and coking wax oil. The conditions for fractionation of the coking reaction separation oil do not affect the properties of the prepared needle coke. The fractionation conditions can be operated according to existing technology. For example, the fractionation conditions include: bottom temperature 300℃-380℃, top temperature 100℃-130℃, and pressure 0.1MPa-0.25MPa. The side-stream extraction temperatures of the coking naphtha, coking diesel oil, and coking wax oil fractions can be operated according to existing technology, and will not be elaborated further in this invention.

[0061] In this invention, the coking medium introduced from the outside in the method for preparing needle coke includes naphtha fraction, gasoline fraction, kerosene fraction, diesel fraction, wax oil fraction, gaseous hydrocarbons with 1 to 3 carbon atoms (methane, ethane, butane), inert gases (nitrogen, argon, carbon dioxide, etc.), and water (water vapor). In the embodiments of this invention, the advantages of this invention are illustrated by using substances selected from the coking reaction system (coked naphtha + coked diesel + coked wax oil) and / or externally introduced substances (diesel fraction, gasoline fraction), but this does not limit the scope of the invention.

[0062] In this invention, the method for preparing needle coke allows for a wide range of selectable mass ratios of the reinforcing agent to the coking medium in the gas stream containing the reinforcing agent. This is an illustrative embodiment, but does not limit the scope of the invention. According to a preferred embodiment, the mass ratio of the reinforcing agent to the coking medium in the gas stream containing the reinforcing agent is 1:100-1:5000. Using the aforementioned technical solution, the prepared needle coke exhibits advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0063] In this invention, the mass ratio of the coking medium to the coking feedstock in the method for preparing needle coke has a wide range of selectable values. This is an illustrative embodiment, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the mass ratio of the coking medium to the coking feedstock is 1:0.2-3. Using the aforementioned technical solution, the prepared needle coke has advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0064] In this invention, coking feedstock undergoes a cracking reaction under high temperature and appropriate pressure, including the cracking of heavy hydrocarbon molecules such as alkanes, cycloalkanes and aromatics into smaller molecules, such as olefins, hydrogen, tar and other reactive oil and gas. In addition, as the cracking reaction proceeds, the intermediate products such as asphaltenes and gums produced begin to form mesophases. These mesophases undergo a series of dehydrogenation, condensation and other chemical reactions at high temperature, and gradually form unstable mesophase spheres.

[0065] In the preparation method of needle coke in this invention, under the action of the coking gas flow, unstable mesophase spheres undergo accumulation and directional arrangement to form the initial structure of needle coke. Aromatic molecules are directionally arranged according to the gas flow direction to form the needle-shaped structure of needle coke. The conditions for the coking-coking reaction can be selected within a wide range. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the conditions for the coking-coking reaction include: the empty tower linear velocity of the coking gas flow is 0.01 m / s-0.3 m / s, preferably 0.05 m / s-0.2 m / s.

[0066] According to a preferred embodiment of the present invention, the conditions for the coking-coking reaction include a temperature of 480℃-620℃.

[0067] According to a preferred embodiment of the present invention, the conditions for the coking-coking reaction include a pressure of 0.2 MPa to 1.2 MPa.

[0068] According to a preferred embodiment of the present invention, the conditions for the coking-coking reaction include a time of 1 h to 48 h. Using the aforementioned technical solution, the prepared needle coke has advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0069] In this invention, the conditions for the mesophase growth reaction in the preparation method of needle coke are available in a wide range. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the conditions for the mesophase growth reaction include a temperature of 420°C-560°C.

[0070] According to a preferred embodiment of the present invention, the conditions for the mesophase growth reaction include a pressure of 0.2 MPa to 1.2 MPa.

[0071] According to a preferred embodiment of the present invention, the conditions for the mesophase growth reaction include a time of 1-48 hours. Using the aforementioned technical solution, the prepared needle coke exhibits advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0072] In this invention, in order to transfer the needle coke product out of the reaction system and prepare for the next coking reaction, steam purging and decoking operations are generally included after the coking reaction is completed. These operations can be carried out in accordance with the prior art, and will not be described in detail in this invention.

[0073] In this invention, commonly used coking feedstocks can be used. The following examples are illustrative but do not limit the scope of the invention. For instance, the coking feedstocks include one or more of catalytic slurry oil, residual oil, tar, crude oil, fuel oil, and asphalt. In the embodiments of this invention, the advantages of the invention are illustrated by using one or more of catalytic slurry oil, vacuum residue, and ethylene tar as coking feedstocks, but this does not limit the scope of the invention.

[0074] In this invention, there are no special requirements for the composition of the coking feedstock. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the density of the coking feedstock is 0.8 g / cm³. 3 -1.1g / cm 3 .

[0075] Those skilled in the art will understand that ash content refers to unburned impurities in coke, such as minerals, during the coking process. According to a preferred embodiment of the present invention, the ash content of the coking raw material is 2 ppm to 150 ppm.

[0076] Those skilled in the art will understand that the four components of coking feedstock refer to four components: saturated components, aromatic components, resins, and asphaltenes. According to a preferred embodiment of the present invention, the content of saturated components in the four components of the coking feedstock is 10 wt%-55 wt%.

[0077] According to a preferred embodiment of the present invention, the aromatic content of the four components of the coking feedstock is 20wt%-60wt%.

[0078] According to a preferred embodiment of the present invention, the content of gum in the four components of the coking feedstock is 10wt%-60wt%.

[0079] According to a preferred embodiment of the present invention, the content of asphaltene in the four components of the coking feedstock is 0.05wt%-5wt%.

[0080] The technical route of this invention is shown in Figure 1. The coking raw material is subjected to a coking reaction to obtain coking reaction separation oil. The reinforcing agent is uniformly dispersed in the coking reaction separation oil to obtain a composite coking medium. The composite coking medium is input into the reaction system during the coking stage of the coking reaction, and high-strength needle coke is obtained after coking.

[0081] In this invention, the coking reactor can be any type of device capable of completing the coking reaction, such as a batch coking unit or a delayed coking unit. The following is an illustrative description, but does not limit the scope of the invention. For example, the coking reactor includes one coke tower (reactor), which is the site where the coking reaction (mesophase growth reaction, coke pulling-coking reaction) occurs and needle coke products are produced; the coking reactor can be a batch coking unit with a single heating furnace and a coke tower (reactor), or a continuous unit consisting of two feed heating furnaces, three coke towers (reactors), and one fractionation tower, as well as necessary liquid conveying components (two furnaces and three towers), or a continuous unit consisting of one feed heating furnace, two coke towers (reactors), and one fractionation tower, as well as necessary liquid conveying components (one furnace and two towers), etc. The embodiments of this invention illustrate the advantages of the invention using a coking reactor with a two-furnace, three-tower configuration. The apparatus flow diagram is shown in Figure 2. This embodiment allows for either single-operation (using any one of coke towers A, B, and C) or continuous operation (using coke towers A, B, and C). For any of the three coke towers, the feed can be switched to either raw material slurry or a composite coking medium. In continuous operation, while raw material slurry is fed to coke tower A, coke towers B and C can perform composite medium coking or decoking operations. The embodiments of this invention illustrate the advantages of the invention using a single-operation configuration (using coke tower A).

[0082] This invention provides needle coke prepared by the method described in this invention.

[0083] The needle coke prepared by the method described in this invention has a wide range of selectable properties such as strength, coefficient of thermal expansion, and electrical conductivity. This invention exemplifies one implementation method but does not limit the scope of the invention. According to a preferred embodiment of this invention, the needle coke prepared by the method described in this invention has a strength of 24%-28% and a coefficient of thermal expansion of 0.9 × 10⁻⁶. -6 / ℃-1.1×10 -6 / ℃, with an electrical conductivity of 1900S / m-3000S / m.

[0084] The beneficial effects of this invention are as follows:

[0085] First, increase the strength of needle coke:

[0086] The reinforcing agent is embedded between the needle-like structures of the needle coke, which can enhance the interaction force between the needle-like structure of the needle coke, the reinforcing agent, and the needle-like structure, thereby increasing the strength of the needle coke.

[0087] Second, reduce the coefficient of thermal expansion of needle coke:

[0088] The reinforcing agent is embedded between the needle-shaped structures of the needle coke, which can buffer the deformation of the needle coke when heated, so that the needle coke has a lower coefficient of thermal expansion.

[0089] Third, improve the electrical conductivity of needle coke:

[0090] The reinforcing agent is embedded between the needle-shaped structures of the needle coke, which not only improves the strength of the needle coke, but also enhances the conductivity between the needle-shaped structures, thereby enhancing the electrical conductivity of the needle coke.

[0091] Fourth, improve the thermal conductivity of needle coke:

[0092] The reinforcing agent is embedded between the needle-shaped structures of the needle coke, which also increases the heat exchange efficiency between the needle-shaped structures, thus resulting in a higher thermal conductivity.

[0093] The present invention will be described in detail below through embodiments.

[0094] Test methods for the properties of coking feedstocks:

[0095] The density was determined according to the method specified in GB / T 1884-1992 "Determination of density of petroleum and liquid petroleum products (hydrometer method)";

[0096] Ash content was determined according to the method in GB / T 508 "Determination of Ash Content in Petroleum Products";

[0097] The contents of the four components—saturated components, aromatic components, resins, and asphaltenes—were determined by the method specified in NBSHT 0509-2010, "Determination of Four Components of Petroleum Asphalt."

[0098] The distillation ranges (5% distillation temperature, 95% distillation temperature, etc.) of naphtha, diesel, and wax oil fractions were determined by the method in ASTM D1160.

[0099] Strength and coefficient of thermal expansion of needle coke: Tested using a CTE tester and an automatic strength tester. CTE testing was performed in accordance with the sample preparation standard GB3074.4-2016, and strength testing was performed in accordance with the standard T / ZGS002-2019.

[0100] Electrical conductivity of needle coke: The powder resistivity method was used, and the test was completed using a Ningbo Ruike Micro Intelligent Co., Ltd. FT-301A powder resistivity / compacted density meter.

[0101] In needle coke, the mass ratio of reinforcing agent to coke is calculated as follows: In one reaction cycle, the mass of feed is M1, the mass of added reinforcing agent is M2, and the mass of high-strength coke product is M3 (M3 contains M2). Then, the mass ratio of reinforcing agent to coke = M3 / M2, and the mass ratio of reinforcing agent to raw material = M2 / M1.

[0102] In this embodiment of the invention, coking feedstock 1 is filtered catalytic slurry collected from PetroChina Jinzhou Petrochemical Company; coking feedstock 2 is vacuum residue collected from PetroChina Liaohe Branch; and coking feedstock 3 is ethylene tar collected from PetroChina Liaoyang Branch. The main properties and components of the three feedstocks are shown in Table 1.

[0103] Table 1

[0104] The coking media used in the embodiments and comparative examples of this invention are naphtha fraction, diesel fraction, and wax oil fraction from the coking reaction system; and externally supplemented diesel fraction (external supplemented medium 1) collected from PetroChina Jinzhou Branch and externally supplemented gasoline fraction (external supplemented medium 2) collected from PetroChina Daqing Branch: the main properties and main components of externally supplemented diesel fraction (external supplemented medium 1) and externally supplemented gasoline fraction (external supplemented medium 2) are shown in Table 2; the main properties and main components of naphtha fraction, diesel fraction, and wax oil fraction from the coking reaction system in Example 1 are shown in Table 2, wherein the main properties and main components such as the distillation range of naphtha fraction, diesel fraction, and wax oil fraction from the coking reaction system in Examples 2-12 are similar to those in Example 1.

[0105] Table 2

[0106] Graphene: Prepared by graphite exfoliation, the number of carbon atom layers in graphene is: 80% with 1 layer and 20% with 2 layers, and the size of graphene (equivalent diameter of graphene sheet size) is 30±10μm.

[0107] Graphite: graphite with 3-4 layers of carbon atoms obtained by exfoliation (60%), 5-6 layers (40%), and a size (equivalent diameter of graphene sheet size) of 50±10μm.

[0108] Carbon nanotubes: Commercially available single-walled carbon nanotubes with an outer diameter of 4-10 nm and a length of 10-30 μm (purchased from Jiangsu Tiannai Co., Ltd.);

[0109] Carbon fiber A: Commercially available 24k carbon fiber, unsized, with a tensile modulus of 230 GPa and a single filament diameter of 8 μm. After pulverization, the single filament length of the powder is 100 ± 20 μm.

[0110] Carbon fiber B: Commercially available 24k carbon fiber, unsized, with a tensile modulus of 230 GPa and a single filament diameter of 8 μm. After pulverization, the single filament length of the powder is 8 ± 1 μm.

[0111] Example 1

[0112] Using catalytic oil slurry as raw material (properties shown in Table 1), 100 kg of catalytic oil slurry (raw material 1) was heated in heater A and then fed into a coking tower for reaction. The reaction time was 18 hours, and the heater temperature was controlled at 460-480℃. During the reaction, the pressure at the top of the coking tower was 0.45-0.5 MPa. All the oil and gas generated from the reaction entered a fractionation tower. The bottom temperature of the fractionation tower was 350-360℃, the top temperature was 100-110℃, and the pressure was 0.15-0.2 MPa. Coking reaction separation oil was separated, including coking naphtha, coking diesel, and coking wax oil. Coke was collected. 10 kg of naphtha, 10 kg of coking diesel, 16 kg of coking wax oil coke, and 14 kg of external naphtha (external supplement medium 2) were added to a mixing tank. 0.01 kg of reinforcing agent graphene was added to the mixing tank. The coking medium mixture was stirred and then pumped into the coke tower for coking after heating in furnace B. The furnace temperature was controlled at 570-590℃, the coke tower top pressure was 0.45-0.5 MPa, and the empty tower linear velocity was 0.09-0.11 m / s. The coking duration was 18 hours. After coking, the coke tower was purged with steam and decoked, yielding 48.26 kg of needle coke. The strength, coefficient of thermal expansion, electrical conductivity, and reinforcing agent content of the obtained needle coke are shown in Table 3.

[0113] Example 2

[0114] Using catalytic oil slurry as raw material (properties shown in Table 1), 100 kg of catalytic oil slurry (raw material 1) was heated in heater A and then fed into a coking tower for reaction. The reaction time was 24 hours, and the heater temperature was controlled at 420-440℃. During the reaction, the pressure at the top of the coking tower was 0.6-0.65 MPa. All the oil and gas generated from the reaction entered a fractionation tower. The bottom temperature of the fractionation tower was 350-360℃, the top temperature was 100-110℃, and the pressure was 0.15-0.2 MPa. Coking reaction separation oil was separated, including coking naphtha, coking diesel, and coke. For coking, 8 kg of coking naphtha, 15 kg of coking diesel oil, and 150 kg of externally supplemented diesel oil (external supplement medium 1) were added to a mixing tank. 0.04 kg of reinforcing carbon nanotubes were added to the mixing tank. The coking medium mixture was stirred and then pumped into the coke tower for coking after heating in furnace B. The furnace temperature was controlled at 490-510℃, the pressure at the top of the coke tower was 0.6-0.65 MPa, and the empty tower linear velocity was 0.11-0.13 m / s. The coking duration was 24 hours. After coking, the coke tower was purged with steam and coke was removed, yielding 46.17 kg of needle coke. The strength, coefficient of thermal expansion, electrical conductivity, and reinforcing agent content of the obtained needle coke are shown in Table 3.

[0115] Example 3

[0116] Using catalytic oil slurry as raw material (properties shown in Table 1), 100 kg of catalytic oil slurry (raw material 1) was heated in heater A and then fed into a coking tower for reaction. The reaction time was 24 hours, and the heater temperature was controlled at 420-440℃. During the reaction, the pressure at the top of the coking tower was 0.6-0.65 MPa. All the oil and gas generated from the reaction entered a fractionation tower. The bottom temperature of the fractionation tower was 350-360℃, the top temperature was 100-110℃, and the pressure was 0.15-0.2 MPa. Coking reaction separation oil was separated, including coking naphtha, coking diesel, and coking wax oil. 8 kg of coking naphtha was taken. 15 kg of coking diesel and 150 kg of externally supplemented diesel (external supplement medium 1) were added to a mixing tank. Reinforcing agents carbon nanotubes and graphene were added to the mixing tank at amounts of 0.035 kg of carbon nanotubes and 0.005 kg of graphene, respectively. The coking medium was mixed using a stirring tank. The mixed composite coking medium was heated in furnace B and pumped into the coke tower for coking. The furnace temperature was controlled at 490-510℃, the pressure at the top of the coke tower was 0.6-0.65 MPa, and the empty tower linear velocity was 0.11-0.13 m / s. The coking duration was 24 hours. After coking, the coke tower was purged with steam and coke was removed, yielding 45.87 kg of needle coke. The strength, coefficient of thermal expansion, electrical conductivity, and reinforcing agent content of the obtained needle coke are shown in Table 3.

[0117] Example 4

[0118] Using vacuum residue as feedstock (properties shown in Table 1), 100 kg of catalytic oil slurry (feedstock 2) was heated in heater A and then fed into a coking tower for reaction. The reaction time was 8 hours, and the heater temperature was controlled at 480-520℃. During the reaction, the pressure at the top of the coking tower was 0.85-0.9 MPa. All the oil and gas generated from the reaction entered a fractionation tower. The bottom temperature of the fractionation tower was 350-360℃, the top temperature was 100-110℃, and the pressure was 0.15-0.2 MPa. Coking reaction separation oil was obtained, including coking naphtha, coking diesel, and coking wax oil. 15 kg of coking naphtha, 15 kg of coking diesel oil, 15 kg of coking wax oil coke, and 5 kg of externally applied naphtha (external supplement medium 2) were added to a mixing tank. 0.1 kg of reinforcing graphite was added to the mixing tank. The coking medium mixture was stirred and then pumped into the coke tower for coking after heating in furnace B. The furnace temperature was controlled at 530-550℃, the pressure at the top of the coke tower was 0.85-0.9 MPa, and the empty tower linear velocity was 0.09-0.11 m / s. The coking duration was 8 hours. After coking, the coke tower was purged with steam and coke was removed, yielding 45.04 kg of needle coke. The strength, coefficient of thermal expansion, electrical conductivity, and the content of reinforcing agent in the needle coke are shown in Table 3.

[0119] Example 5

[0120] Using catalytic slurry oil and vacuum residue as feedstocks (properties shown in Table 1), 70 kg of catalytic slurry oil (feedstock 1) and 30 kg of vacuum residue oil (feedstock 2) were heated in heater A and then fed into a coking tower for reaction. The reaction time was 48 hours, and the heater temperature was controlled at 520-560℃. During the reaction, the pressure at the top of the coking tower was 0.65-0.7 MPa. All the oil and gas generated from the reaction entered a fractionation tower. The bottom temperature of the fractionation tower was 350-360℃, the top temperature was 100-110℃, and the pressure was 0.15-0.2 MPa. Coking reaction separation oil was separated, including coking naphtha and coking oil. Diesel fuel, coking wax oil, and 15 kg of coking naphtha, 15 kg of coking diesel fuel, 15 kg of coking wax oil, and 5 kg of externally applied naphtha (external supplementary medium 2) were added to a mixing tank. 0.4 kg of reinforcing agent carbon fiber A was added to the mixing tank. The coking medium mixture was stirred and mixed. The resulting composite coking medium was heated in furnace B and pumped into the coke tower for coking. The furnace temperature was controlled at 590-610℃, the coke tower top pressure was 0.65-0.7 MPa, and the empty tower linear velocity was 0.13-0.15 m / s. The coking duration was 48 hours. After coking, the coke tower was purged with steam and decoked, yielding 45.56 kg of needle coke. The strength, coefficient of thermal expansion, electrical conductivity, and reinforcing agent content of the obtained needle coke are shown in Table 3.

[0121] Example 6

[0122] Using catalytic oil slurry and ethylene tar as raw materials (properties shown in Table 1), 80 kg of catalytic oil slurry (raw material 1) and 20 kg of ethylene tar (raw material 3) were heated in heater A and then fed into a coking tower for reaction. The reaction time was 18 hours, and the heater temperature was controlled at 480-500℃. During the reaction, the pressure at the top of the coking tower was 0.5-0.6 MPa. All the oil and gas generated from the reaction entered a fractionation tower. The bottom temperature of the fractionation tower was 350-360℃, the top temperature was 100-110℃, and the pressure was 0.15-0.2 MPa. Coking reaction separation oil, including coking naphtha and coke, was separated. Diesel fuel, coking wax oil, 10 kg of coking naphtha, 10 kg of coking diesel fuel, 2 kg of coking wax oil, and 28 kg of externally supplemented diesel fuel (external supplementation medium 1) were added to a mixing tank. 0.01 kg of reinforcing agent graphene was added to the mixing tank. The coking medium was mixed by stirring. The mixed composite coking medium was heated in furnace B and pumped into the coke tower for coking. The furnace temperature was controlled at 580-600℃, the pressure at the top of the coke tower was 0.5-0.6 MPa, and the empty tower linear velocity was 0.08-0.09 m / s. The coking duration was 18 hours. After coking, the coke tower was purged with steam for coke removal, yielding 44.12 kg of needle coke. The strength, coefficient of thermal expansion, electrical conductivity, and the content of reinforcing agent in the needle coke are shown in Table 3.

[0123] Example 7

[0124] Using catalytic oil slurry as raw material (properties shown in Table 1), 100 kg of catalytic oil slurry (raw material 1) was heated in heater A and then fed into the coking tower for reaction. The reaction time was 18 hours, and the heater temperature was controlled at 460-480℃. During the reaction, the pressure at the top of the coking tower was 0.45-0.5 MPa. 50 kg of external naphtha (external feed medium 2) was added to the mixing tank. 0.01 kg of reinforcing agent graphene was added to the mixing tank. The coking medium was mixed by stirring. The mixed composite coking medium was heated in heater B and pumped into the coking tower for coking. The heater temperature was controlled at 570-590℃, the pressure at the top of the coking tower was 0.45-0.5 MPa, and the empty tower linear velocity was 0.09-0.11 m / s. The coking duration was 18 hours. After coking, the coking tower was purged with steam and decoked, yielding 48.07 kg of needle coke. The strength, coefficient of thermal expansion, electrical conductivity, and content of reinforcing agent in the obtained needle coke are shown in Table 3.

[0125] Example 8

[0126] Using catalytic slurry oil and vacuum residue as feedstocks (properties shown in Table 1), 70 kg of catalytic slurry oil (feedstock 1) and 30 kg of vacuum residue oil (feedstock 2) were heated in heater A and then fed into a coking tower for reaction. The reaction time was 48 hours, and the heater temperature was controlled at 520-560℃. During the reaction, the pressure at the top of the coking tower was 0.65-0.7 MPa. All the oil and gas generated from the reaction entered a fractionation tower. The bottom temperature of the fractionation tower was 350-360℃, the top temperature was 100-110℃, and the pressure was 0.15-0.2 MPa. Coking reaction separation oil, including coking naphtha and coke, was separated. Diesel fuel, coking wax oil, and 15 kg of coking naphtha, 15 kg of coking diesel fuel, 15 kg of coking wax oil, and 5 kg of externally supplemented naphtha (external supplement medium 2) were added to a mixing tank. 2 kg of reinforcing agent carbon fiber A was added to the mixing tank. The coking medium was mixed using a stirring motion. The mixed composite coking medium was heated in furnace B and pumped into a coke tower for coking. The furnace temperature was controlled at 590-610℃, the coke tower top pressure was 0.65-0.7 MPa, and the empty tower linear velocity was 0.13-0.15 m / s. The coking duration was 48 hours. After coking, the coke tower was purged with steam for purging and coke removal, yielding 47.24 kg of needle coke. The strength, coefficient of thermal expansion, electrical conductivity, and reinforcing agent content of the obtained needle coke are shown in Table 3.

[0127] Example 9

[0128] Using catalytic slurry oil and vacuum residue as feedstocks (properties shown in Table 1), 70 kg of catalytic slurry oil (feedstock 1) and 30 kg of vacuum residue oil (feedstock 2) were heated in heater A and then fed into a coking tower for reaction. The reaction time was 48 hours, and the heater temperature was controlled at 520-560℃. During the reaction, the pressure at the top of the coking tower was 0.65-0.7 MPa. All the oil and gas generated from the reaction entered a fractionation tower. The bottom temperature of the fractionation tower was 350-360℃, the top temperature was 100-110℃, and the pressure was 0.15-0.2 MPa. Coking reaction separation oil was separated, including coking naphtha and coking oil. Diesel fuel, coking wax oil, and 15 kg of coking naphtha, 15 kg of coking diesel fuel, 15 kg of coking wax oil, and 5 kg of externally supplemented naphtha (external supplement medium 2) were added to a mixing tank. 0.4 kg of reinforcing agent carbon fiber B was added to the mixing tank. The coking medium mixture was stirred and mixed. The resulting composite coking medium was heated in furnace B and pumped into the coke tower for coking. The furnace temperature was controlled at 590-610℃, the coke tower top pressure was 0.65-0.7 MPa, and the empty tower linear velocity was 0.13-0.15 m / s. The coking duration was 48 hours. After coking, the coke tower was purged with steam and decoked, yielding 45.13 kg of needle coke. The strength, coefficient of thermal expansion, electrical conductivity, and reinforcing agent content of the obtained needle coke are shown in Table 3.

[0129] Example 10

[0130] Using catalytic oil slurry as raw material (properties shown in Table 1), 100 kg of catalytic oil slurry (raw material 1) was heated in heater A and then fed into a coking tower for reaction. The reaction time was 18 hours, and the heater temperature was controlled at 460-480℃. During the reaction, the pressure at the top of the coking tower was 0.45-0.5 MPa. All the oil and gas generated from the reaction entered a fractionation tower. The bottom temperature of the fractionation tower was 350-360℃, the top temperature was 100-110℃, and the pressure was 0.15-0.2 MPa. Coking reaction separation oil was separated, including coking naphtha, coking diesel oil, and coking wax oil. 10 kg of coking naphtha, 10 kg of coking diesel oil, 16 kg of coking wax oil, and 14 kg of externally supplemented naphtha (external supplement medium 2) were added to a mixing tank. 0.01 kg of reinforcing agent graphene was added to the mixing tank. The coking medium mixture was stirred and then pumped into the coke tower for coking after heating in furnace B. The furnace temperature was controlled at 400-420℃, the pressure at the top of the coke tower was 0.45-0.5 MPa, and the empty tower linear velocity was 0.09-0.11 m / s. The coking duration was 18 hours. After coking, the coke tower was purged with steam and coke was removed, yielding 48.93 kg of needle coke. The strength, coefficient of thermal expansion, electrical conductivity, and the content of reinforcing agent in the needle coke are shown in Table 3.

[0131] Example 11

[0132] Using catalytic oil slurry as raw material (properties shown in Table 1), 100 kg of catalytic oil slurry (raw material 1) was heated in heater A and then fed into a coking tower for reaction. The reaction time was 18 hours, and the heater temperature was controlled at 460-480℃. During the reaction, the pressure at the top of the coking tower was 0.45-0.5 MPa. All the oil and gas generated from the reaction entered a fractionation tower. The bottom temperature of the fractionation tower was 350-360℃, the top temperature was 100-110℃, and the pressure was 0.15-0.2 MPa. Coking reaction separation oil was separated, including coking naphtha, coking diesel oil, and coking wax oil. 10 kg of coking naphtha, 10 kg of coking diesel oil, 16 kg of coking wax oil, and 14 kg of externally supplemented naphtha (external supplement medium 2) were added to a mixing tank. 0.01 kg of reinforcing agent graphene was added to the mixing tank. The coking medium mixture was stirred and then pumped into the coke tower for coking after heating in furnace B. The furnace temperature was controlled at 570-590℃, the coke tower top pressure was 0.45-0.5 MPa, and the empty tower linear velocity was 0.03-0.04 m / s. The coking duration was 18 hours. After coking, the coke tower was purged with steam and coke was removed, yielding 48.78 kg of needle coke. The strength, coefficient of thermal expansion, electrical conductivity, and the content of reinforcing agent in the needle coke are shown in Table 3.

[0133] Example 12

[0134] Using catalytic oil slurry as raw material (properties shown in Table 1), 100 kg of catalytic oil slurry (raw material 1) was heated in heater A and then fed into a coking tower for reaction. The reaction time was 24 hours, and the heater temperature was controlled at 420-440℃. During the reaction, the pressure at the top of the coking tower was 0.6-0.65 MPa. All the oil and gas generated from the reaction entered a fractionation tower. The bottom temperature of the fractionation tower was 350-360℃, the top temperature was 100-110℃, and the pressure was 0.15-0.2 MPa. Coking reaction separation oil was separated, including coking naphtha, coking diesel oil, and coking wax oil. 8 kg of coking naphtha, 15 kg of coking diesel oil, and 150 kg of externally supplemented diesel oil (external supplement medium 1) were added to a mixing tank. 0.004 kg of carbon nanotubes, a reinforcing agent, were added to the mixing tank. The coking medium was mixed using a stirring motion. The resulting composite coking medium was heated in furnace B and pumped into the coke tower for coking. The furnace temperature was controlled at 490-510℃, the pressure at the top of the coke tower was 0.6-0.65 MPa, and the empty tower linear velocity was 0.11-0.13 m / s. The coking duration was 24 hours. After coking, the coke tower was purged with steam for scavenging and coke removal, yielding 46.67 kg of needle coke. The strength, coefficient of thermal expansion, electrical conductivity, and reinforcing agent content of the obtained needle coke are shown in Table 3.

[0135] Comparative Example 1

[0136] Similar to Example 1, except that no reinforcing agent was added, and all other conditions were the same, resulting in 48.91 kg of needle coke. The strength, coefficient of thermal expansion, electrical conductivity, and reinforcing agent content of the obtained needle coke are shown in Table 3.

[0137] Comparative Example 2

[0138] Similar to Example 1, except that the reinforcing agent was added to the feedstock slurry and entered the reaction system along with it, instead of being introduced into the reaction system during the coking stage. All other conditions were the same, yielding 48.55 kg of needle coke. The strength, coefficient of thermal expansion, electrical conductivity, and reinforcing agent content of the obtained needle coke are shown in Table 3.

[0139] Comparative Example 3

[0140] Similar to Example 3, except that the reinforcing medium was added to the feedstock slurry and entered the reaction system along with it, instead of being introduced into the reaction system during the coking stage. All other conditions remained the same. 45.63 kg of needle coke was obtained. The strength, coefficient of thermal expansion, electrical conductivity, and reinforcing agent content of the obtained needle coke are shown in Table 3.

[0141] Table 3

[0142] As shown in Table 3, the strength of Examples 1-4, due to the addition of reinforcing media during the coking process, is higher than that of Comparative Example 1. In Comparative Examples 2-3, adding reinforcing media to the raw material is less effective than adding it during the coking process. It is speculated that adding reinforcing media before the formation of the mesophase may negatively impact mesophase formation, leading to a decrease in strength. Therefore, the optimal time to introduce reinforcing media is during the coking stage, and its reinforcing effect depends on the distribution and directionality of the coking airflow. Combining the results of Examples 1-12 and Comparative Examples 1-3, the implementation scheme provided by this invention can significantly improve the performance of needle coke.

[0143] The preferred 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 combinations of 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. Needle coke, characterized in that, The needle coke contains a reinforcing agent embedded between the needle-shaped structures of the needle coke. The needle coke has a strength of 24%-28% and a coefficient of thermal expansion of 0.9 × 10⁻⁶. -6 / ℃-1.1×10 -6 / ℃, with an electrical conductivity of 1900S / m-3000S / m.

2. The needle coke according to claim 1, characterized by, The electrical conductivity of needle coke is 1900 S / m-2650 S / m.

3. The needle coke according to claim 1 or 2, characterized in that, In the needle coke, the content of the reinforcing agent is 0.02wt%-1wt%; And / or the reinforcing agent is introduced in situ during the coking process.

4. The needle coke according to claim 1 or 2, characterized in that, The reinforcing agent includes one-dimensional carbon materials and / or two-dimensional carbon materials; Along the axial or planar direction of the reinforcing agent, the equivalent diameter of the length or sheet size of the reinforcing agent is 0.2 μm-200 μm; The diameter or thickness of the reinforcing agent is 0.2 nm to 15 μm in a direction perpendicular to the axis or plane of the reinforcing agent.

5. The needle coke according to claim 4, characterized in that, The one-dimensional carbon material is selected from one or more of carbon nanotubes, carbon fibers, and graphite fibers; Along the axial direction of the one-dimensional carbon material, the length of the one-dimensional carbon material is 10μm-150μm; The diameter of the one-dimensional carbon material is 1 nm-10 μm, perpendicular to the axis of the one-dimensional carbon material.

6. The needle coke according to claim 4, characterized in that, The two-dimensional carbon material is selected from graphene and / or graphite. Along the direction of the surface of the two-dimensional carbon material, the equivalent diameter of the sheet size of the two-dimensional carbon material is 20μm-100μm; The two-dimensional carbon material has 1-30 layers of carbon atoms.

7. The needle coke according to claim 1 or 2, characterized in that, The reinforcing agent includes one-dimensional carbon materials and two-dimensional carbon materials, each with a content of not less than 10 wt%.

8. A method for producing needle coke, characterized by, The method includes: (1) Coking feedstock undergoes mesophase growth reaction to form mesophase spheres; (2) In an airflow containing reinforcing agents, the mesophase spheres undergo a coking-coking reaction; The mass ratio of the amount of the reinforcing agent to the amount of the coking raw material is 1:100-1:30000.

9. The method according to claim 8, characterized in that, The reinforcing agent includes one-dimensional carbon materials and / or two-dimensional carbon materials; Along the axial or planar direction of the reinforcing agent, the equivalent diameter of the length or sheet size of the reinforcing agent is 0.2 μm-200 μm; The diameter or thickness of the reinforcing agent is 0.2 nm to 15 μm in a direction perpendicular to the axis or plane of the reinforcing agent.

10. The method according to claim 9, characterized in that, The one-dimensional carbon material is selected from one or more of carbon nanotubes, carbon fibers, and graphite fibers; Along the axial direction of the one-dimensional carbon material, the length of the one-dimensional carbon material is 10μm-150μm; The diameter of the one-dimensional carbon material is 1 nm-10 μm, perpendicular to the axis of the one-dimensional carbon material.

11. The method according to claim 9, characterized in that, The two-dimensional carbon material is selected from graphene and / or graphite; Along the direction of the surface of the two-dimensional carbon material, the equivalent diameter of the sheet size of the two-dimensional carbon material is 20μm-100μm; The two-dimensional carbon material has 1-30 layers of carbon atoms.

12. The method according to claim 8 or 9, characterized in that, The reinforcing agent includes one-dimensional carbon materials and two-dimensional carbon materials, each with a content of not less than 10 wt%.

13. The method according to claim 8 or 9, characterized in that, The reinforcing agent is dispersed in the coking medium to form the gas flow containing the reinforcing agent; the coking medium is selected from one or more of naphtha fraction, gasoline fraction, kerosene fraction, diesel fraction, wax oil fraction, gaseous hydrocarbons with 1 to 3 carbon atoms, inert gases, and water.

14. The method according to claim 13, characterized in that, The coking medium includes at least two of naphtha fraction, diesel fraction, and wax oil fraction.

15. The method according to claim 14, characterized in that, The 5% distillation temperature of naphtha fraction is 40℃-70℃, and the 95% distillation temperature of naphtha fraction is 150℃-190℃. The 5% distillation temperature of diesel fraction is 190℃-240℃, and the 95% distillation temperature of diesel fraction is 300℃-350℃. The 5% distillation temperature of the wax oil fraction is 250℃-300℃, and the 95% distillation temperature of the wax oil fraction is 380℃-420℃.

16. The method according to claim 13, characterized in that, In the gas stream containing the reinforcing agent, the mass ratio of the reinforcing agent to the coking medium is 1:100-1:5000; The mass ratio of the coking medium to the coking raw material is 1:0.2-3.

17. The method according to any one of claims 8-11, characterized in that, The conditions for the coking-coking reaction include: The linear velocity of the coking gas flow in the empty tower is 0.01 m / s - 0.3 m / s; The temperature ranges from 480℃ to 620℃. The pressure is 0.2 MPa - 1.2 MPa; The time ranges from 1 hour to 48 hours.

18. The method according to any one of claims 8-11, characterized in that, The conditions for the mesophase growth reaction include: The temperature ranges from 420℃ to 560℃. The pressure is 0.2 MPa - 1.2 MPa; The time is 1-48 hours.

19. The method according to any one of claims 8-11, characterized in that, The coking feedstock includes one or more of the following: catalytic slurry oil, residual oil, tar, crude oil, fuel oil, and asphalt; The density of the coked feedstock is 0.8 g / cm 3 -1.1 g / cm 3 ; The ash content of the coking raw material is 2ppm-150ppm; Of the four components of the coking feedstock, The content of saturated components is 10wt%-55wt%, and the content of aromatic components is 20wt%-60wt%. The content of resin is 10wt%-60wt%, and the content of asphaltene is 0.05wt%-5wt%.

20. A needle coke prepared by the method of any one of claims 8-19.

21. The needle coke according to claim 20, having a strength of 24-28%, a thermal expansion coefficient of 0.9 x 10 -6 / °C - 1.1 x 10 -6 / °C, and an electrical conductivity of 1900 S / m - 3000 S / m.

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