Needle coke and preparation method thereof

Abstract

The invention relates to the field of needle coke, and discloses needle coke and a preparation method thereof, the needle coke contains a reinforcing agent, the reinforcing agent is embedded between needle-shaped structures of the needle coke, the strength of the needle coke is 24%-28%, the thermal expansion coefficient is 0.9 * 10 <-6 > / DEG C to 1.1 * 10 <-6 > / DEG C, and the conductivity is 1900S / m to 3000S / m. The preparation method of the needle coke comprises the following steps: (1) performing an intermediate phase growth reaction on a coking raw material to form an intermediate phase sphere; (2) carrying out coke drawing-coke forming reaction on the mesophase spheres in air flow containing a reinforcing agent; the mass ratio of the dosage of the reinforcing agent to the dosage of the coking raw material is (1: 100)-(1: 30000). The needle coke disclosed by the invention has the advantages of higher strength, lower thermal expansion coefficient, higher conductivity and the like, and is suitable for being applied to materials such as metallurgical electrodes, battery electrodes and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of needle coke, and particularly relates to a needle coke and a preparation method thereof. Background Art

[0002] As a high-quality carbon material, needle coke 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 requirements for electrode performance in fields such as steel smelting and electrolytic aluminum, the demand for graphite electrodes, especially ultra-high power graphite electrodes, is growing day by day. Ultra-high power graphite electrodes play an irreplaceable role in the smelting industry with their high thermal shock resistance, high mechanical strength, excellent oxidation resistance, low electrode consumption, and allowable high current density. And needle coke, as the key raw material for manufacturing ultra-high power graphite electrodes, the quality of it directly affects the performance and service life of the electrodes.

[0003] Among the numerous 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 effect in graphite electrodes. Lower needle coke strength may lead to problems such as cracks and fractures during the manufacturing and use of electrodes, seriously affecting the integrity and service performance of the electrodes. Therefore, improving the strength of needle coke is of great significance for improving the performance of graphite electrodes and extending the service life of the electrodes.

[0004] The factors affecting the strength of needle coke include the size and density of internal pores in the material, CTE, the composition of coking raw materials, the size and shape of grains, and the process conditions during the preparation process, etc. Current research mostly improves the strength by adjusting the process conditions during the preparation process. For example, process conditions such as thermal conversion temperature, pressure, residence time, and heating rate will directly affect the condensation reaction and the formation of mesophase, thereby affecting the strength of the finally formed needle coke. For example, Qi et al. (CN113698956A) proposed a production process for improving the compressive strength of needle coke. By pretreating the coking raw materials, impurities in the coking raw materials were removed, and the purity of the coking raw materials was improved. In the subsequent coke production reaction, by optimizing parameters such as the circulation ratio of recycle oil and heating temperature, the gradual heating of the coke tower was achieved, and the compressive strength of the needle coke was improved. However, this method only relies on process parameter control and has limited improvement in strength.

[0005] In addition, there is also research on improving the strength of needle coke through post-treatment. For example, Liao et al. (CN115745610A) made petroleum coke into fine powder, added graphene aqueous solution and dispersant for coating, roasted, impregnated, and secondarily roasted the green body obtained by rolling and molding, and then carried out high-temperature purification to obtain a high-strength carbonene graphite material. This method has complex processes, requires multiple temperature increases, and has a high cost. Summary of the Invention

[0006] The object of the present invention is to solve the problems of low strength, poor electrical conductivity, and poor thermal expansion resistance of existing needle coke, and to provide a needle coke and a preparation method thereof. The needle coke of the present invention has advantages such as higher strength, lower thermal expansion coefficient, and higher electrical conductivity, and is suitable for use in materials such as metallurgical electrodes and battery electrodes.

[0007] To achieve the above object, on the one hand, the present invention provides a needle coke, which contains a reinforcing agent, and the reinforcing agent is embedded between the needle-shaped structures of the needle coke. The strength of the needle coke is 24%-28%, the thermal expansion coefficient is 0.9×10 -6 / ℃ - 1.1×10 -6 / ℃, and the electrical conductivity is 1900 S / m - 3000 S / m.

[0008] On the second hand, the present invention provides a preparation method of a needle coke, which includes: (1) The coking raw material undergoes a mesophase growth reaction to form mesophase spheres; (2) In an air flow containing a reinforcing agent, the mesophase spheres undergo a pulling coke - coking reaction; the mass ratio of the dosage of the reinforcing agent to the dosage of the coking raw material is 1:100 - 1:30000.

[0009] On the third hand, the present invention provides the needle coke prepared by the method described in the present invention.

[0010] The beneficial effects of the present invention are as follows:

[0011] First, improve the strength of the needle coke:

[0012] The reinforcing agent is embedded between the needle-shaped structures of the needle coke, which can enhance the force between the needle-shaped structures - reinforcing agent - needle-shaped structures of the needle coke, thereby enhancing the strength of the needle coke;

[0013] Second, reduce the thermal expansion coefficient of the needle coke:

[0014] 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 thermal expansion coefficient;

[0015] Third, improve the electrical conductivity of the needle coke:

[0016] The reinforcing agent is embedded between the needle-shaped structures of the needle coke. While improving the strength of the needle coke, it also enhances the electrical conductivity between the needle-shaped structures, thereby enhancing the electrical conductivity of the needle coke;

[0017] Fourth, improve the thermal conductivity of the needle coke:

[0018] The reinforcing agent is embedded between the needle-shaped structures of the needle coke, and also increases the heat exchange efficiency between the needle-shaped structures, thereby having a higher thermal conductivity. Description of the Drawings

[0019] Figure 1 is a schematic diagram of the technical route of the present invention;

[0020] Figure 2 is a flowchart of the device for producing needle coke according to the present invention. Detailed implementation manners

[0021] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0022] The present invention provides a needle coke, which contains a reinforcing agent. The reinforcing agent is embedded between the needle-shaped structures of the needle coke. The strength of the needle coke is 24%-28%, the coefficient of thermal expansion is 0.9×10 -6 / °C - 1.1×10 -6 / °C, and the conductivity is 1900 S / m - 3000 S / m.

[0023] According to a preferred embodiment of the present invention, the conductivity of the needle coke is 1900 S / m - 2650 S / m. With the foregoing technical solution, the needle coke has advantages such as higher strength, lower coefficient of thermal expansion, and higher conductivity.

[0024] According to a preferred embodiment of the present invention, in the needle coke, the content of the reinforcing agent is 0.02 wt% - 1 wt%. With the foregoing technical solution, the needle coke has advantages such as higher strength, lower coefficient of thermal expansion, and higher conductivity.

[0025] In the present invention, the needle coke having the foregoing technical features can all achieve the purpose of the present invention. The optional range of the introduction method of the reinforcing agent is relatively wide. A preferred embodiment is demonstrated, but it does not limit the scope of the present invention. According to a preferred embodiment of the present invention, the reinforcing agent is introduced in situ during the coke pulling process.

[0026] In the present invention, the optional range of the type of the reinforcing agent is relatively wide. A preferred embodiment is demonstrated, but it does not limit the scope of the present invention. According to a preferred embodiment of the present invention, the reinforcing agent includes one-dimensional carbon materials and / or two-dimensional carbon materials. With the foregoing technical solution, the needle coke has advantages such as higher strength, lower coefficient of thermal expansion, and higher conductivity.

[0027] In the present invention, the optional range of the size of the reinforcing agent is relatively wide. The following is a demonstration, but it does not limit the scope of the present invention. According to a preferred embodiment of the present invention, along the axis or plane direction of the reinforcing agent, the equivalent diameter of the length or sheet size of the reinforcing agent is 0.2 μm - 200 μm.

[0028] According to a preferred embodiment of the present invention, in the direction perpendicular to the axis or plane of the reinforcing agent, the diameter or thickness of the reinforcing agent is 0.2 nm - 15 μm. By adopting the foregoing technical solution, the needle coke has advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0029] In the present invention, common one-dimensional carbon materials can all achieve the purpose of the present invention. The optional range of the types of one-dimensional carbon materials is relatively wide. A demonstration of an embodiment is given below, but it does not limit the scope of the present invention. According to a preferred embodiment of the present invention, the one-dimensional carbon material is selected from one or more of carbon nanotubes, carbon fibers, and graphite fibers. By adopting the foregoing technical solution, the needle coke has advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0030] In the present invention, the optional range of the size of the one-dimensional carbon material is relatively wide. The following is a demonstration, but it does not limit the scope of the present invention. According to a preferred embodiment of the present invention, along the axis direction of the one-dimensional carbon material, the length of the one-dimensional carbon material is 10 μm - 150 μm.

[0031] According to a preferred embodiment of the present invention, in the direction perpendicular to the axis of the one-dimensional carbon material, the diameter of the one-dimensional carbon material is 1 nm - 10 μm. By adopting the foregoing technical solution, the needle coke has advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0032] In the present invention, the advantages of the present invention are illustrated by using carbon nanotubes and / or carbon fibers as the one-dimensional carbon material. Among them, the carbon nanotubes are commercially available multi-walled carbon nanotubes with an outer diameter of 10 nm - 20 nm and a length of 10 μm - 30 μm; the carbon fibers are commercially available 24k carbon fibers, without sizing treatment, a tensile modulus of 230 GPa, a single filament diameter of 8 μm, and are pulverized. The single filament length of the powder after treatment is 100 ± 20 μm.

[0033] In the present invention, the optional range of the two-dimensional carbon material is relatively wide. A demonstration of an embodiment is given below, but it does not limit the scope of the present invention. According to a preferred embodiment of the present invention, the two-dimensional carbon material is selected from graphene and / or graphite. By adopting the foregoing technical solution, the needle coke has advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0034] In the present invention, the optional range of the size of the two-dimensional carbon material is relatively wide, which is demonstrated by way of example below, but does not limit the scope of the present invention thereby. According to a preferred embodiment of the present invention, along the direction of the plane of the two-dimensional carbon material, the equivalent diameter of the sheet size of the two-dimensional carbon material is 20 μm - 100 μm.

[0035] According to a preferred embodiment of the present invention, the number of carbon atom layers of the two-dimensional carbon material is 1 - 30 layers, such as 5 layers, 10 layers, 15 layers, 20 layers and 25 layers. Those skilled in the art know that the thickness of a single carbon atom layer of the two-dimensional carbon material is about 0.34 nanometers. By adopting the foregoing technical solution, needle coke has advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0036] In the present invention, the advantages of the present invention are illustrated by using graphene and / or graphite as the two-dimensional carbon material. Among them, graphene: prepared by exfoliating graphite, the number of carbon atom layers of graphene is: 80% for 1 layer, 20% for 2 layers, and the size of graphene is 30 ± 10 μm; graphite: exfoliated to obtain the number of carbon atom layers of: 60% for 3 - 4 layers, 40% for 5 - 6 layers, and the size of graphite is 50 ± 10 μm.

[0037] According to a preferred embodiment of the present invention, the reinforcing agent includes one-dimensional carbon material and two-dimensional carbon material, and the content of each of them is not less than 10 wt%. By adopting the foregoing technical solution, under the combined action of the one-dimensional carbon material and the two-dimensional carbon material, the binding force in multiple dimensions between the needle-shaped structures can be realized and a three-dimensional conductive network can be constructed, so that needle coke has advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0038] The second aspect of the present invention provides a method for preparing needle coke, which includes: (1) the coking raw material undergoes a mesophase growth reaction to form mesophase spheres; (2) in a gas stream containing a reinforcing agent, the mesophase spheres undergo a pulling-coking and coking reaction; the mass ratio of the dosage of the reinforcing agent to the dosage of the coking raw material is 1:100 - 1:30000.

[0039] The method for preparing needle coke of the present invention in-situ introduces a reinforcing agent during the pulling-coking and coking reaction process, so that the reinforcing agent forms an oriented inlaid structure between the mesophase sphere structures, and this inlay is in-situ combined when the mesophase spheres are transformed into needle coke, realizing the in-situ strengthening of needle coke during the preparation process. The prepared needle coke has advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0040] In the present invention, in the method for preparing needle coke, the range of optional types of reinforcing agents is relatively wide. A preferred embodiment is demonstrated herein without limiting the scope of the present invention thereby. According to a preferred embodiment of the present invention, the reinforcing agent includes one-dimensional carbon materials and / or two-dimensional carbon materials. By adopting the foregoing technical solution, the prepared needle coke has advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0041] In the present invention, in the method for preparing needle coke, the range of optional sizes of the reinforcing agent is relatively wide. A demonstration is given below without limiting the scope of the present invention thereby. According to a preferred embodiment of the present invention, 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.

[0042] In the present invention, in the method for preparing needle coke, according to a preferred embodiment of the present invention, in the direction perpendicular to the axis or plane of the reinforcing agent, the diameter or thickness of the reinforcing agent is 0.2 nm - 15 μm. By adopting the foregoing technical solution, the prepared needle coke has advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0043] In the present invention, in the method for preparing needle coke, the range of optional types of one-dimensional carbon materials is relatively wide. A preferred embodiment is demonstrated herein without limiting the scope of the present invention thereby. According to a preferred embodiment of the present invention, the one-dimensional carbon material is selected from one or more of carbon nanotubes, carbon fibers, and graphite fibers. By adopting the foregoing technical solution, the prepared needle coke has advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0044] In the present invention, in the method for preparing needle coke, the range of optional sizes of the one-dimensional carbon material is relatively wide. A demonstration is given below without limiting the scope of the present invention thereby. According to a preferred embodiment of the present invention, along the axial direction of the one-dimensional carbon material, the length of the one-dimensional carbon material is 10 μm - 150 μm.

[0045] According to a preferred embodiment of the present invention, in the direction perpendicular to the axis of the one-dimensional carbon material, the diameter of the one-dimensional carbon material is 1 nm - 10 μm. By adopting the foregoing technical solution, the prepared needle coke has advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0046] In the present invention, in the method for preparing needle coke, the use of one-dimensional carbon materials, namely carbon nanotubes and / or carbon fibers, illustrates the advantages of the present invention. Among them, the carbon nanotubes are commercially available multi-walled carbon nanotubes with an outer diameter of 10 nm - 20 nm and a length of 10 μm - 30 μm; the carbon fibers are commercially available 24k carbon fibers without sizing treatment, with a tensile modulus of 230 GPa, a single filament diameter of 8 μm, and are subjected to comminution treatment, and the single filament length of the powder after treatment is 100 ± 20 μm.

[0047] In the present invention, in the method for preparing needle coke, the optional range of two-dimensional carbon materials is relatively wide. One embodiment is demonstrated by way of example, but this does not limit the scope of the present invention. According to a preferred embodiment of the present invention, the two-dimensional carbon material is selected from graphene and / or graphite. By adopting the foregoing technical solution, the prepared needle coke has advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0048] In the present invention, in the method for preparing needle coke, the optional range of the size of the two-dimensional carbon material is relatively wide. The following is demonstrated by way of example, but this does not limit the scope of the present invention. According to a preferred embodiment of the present invention, along the direction of the plane of the two-dimensional carbon material, the equivalent diameter of the sheet size of the two-dimensional carbon material is 20 μm - 100 μm.

[0049] In the present invention, in the method for preparing needle coke, according to a preferred embodiment of the present invention, the number of carbon atom layers of the two-dimensional carbon material is 1 - 30 layers, such as 5 layers, 10 layers, 15 layers, 20 layers, and 25 layers. Those skilled in the art know that the thickness of a single layer of carbon atom layer of two-dimensional carbon material is about 0.34 nanometers. By adopting the foregoing technical solution, the prepared needle coke has advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0050] In the present invention, in the method for preparing needle coke, the use of graphene and / or graphite as the two-dimensional carbon material illustrates the advantages of the present invention. Among them, graphene: prepared by exfoliating graphite, the number of carbon atom layers of graphene is: 80% for 1 layer, 20% for 2 layers, and the size of graphene is 30 ± 10 μm; graphite: exfoliated to obtain carbon atom layers of: 60% for 3 - 4 layers, 40% for 5 - 6 layers, and graphite with a size of 50 ± 10 μm.

[0051] In the present invention, in the method for preparing needle coke, according to a preferred embodiment of the present invention, the reinforcing agent includes one-dimensional carbon materials and two-dimensional carbon materials, and the content of each of them is not less than 10 wt%. By adopting the foregoing technical solution, under the combined action of one-dimensional carbon materials and two-dimensional carbon materials, the binding force in multiple dimensions between needle-shaped structures can be realized and a three-dimensional conductive network can be constructed. The prepared needle coke has advantages such as higher strength, lower coefficient of thermal expansion, and higher electrical conductivity.

[0052] In the present invention, in the method for preparing needle coke, in a gas stream containing a reinforcing agent, mesophase spheres undergo the processes of drawing coke and coke formation. There are no special requirements for the method of preparing the gas stream containing the reinforcing agent, and 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 is dispersed in a coke-drawing medium to form the gas stream containing the reinforcing agent. Here, the coke-drawing medium is a substance that is easily vaporized or is a gas itself, which is used to generate a coke-drawing gas stream and participates in the coke-drawing and coke-formation reactions. The range of sources and types of the coke-drawing medium is relatively wide. For example, the coke-drawing medium can come from a coking reaction system and / or be introduced from the outside, and the coke-drawing medium can be selected from one or more of a naphtha fraction, a gasoline fraction, a kerosene fraction, a diesel fraction, a wax oil fraction, gaseous hydrocarbons with 1 to 3 carbon atoms (methane, ethane, butane), inert gases (nitrogen, argon, carbon dioxide, etc.), and water (steam).

[0053] In the present invention, in the method for preparing needle coke, there are no special requirements for the dispersion method of the reinforcing agent dispersed in the coke-drawing medium to form the gas stream containing the reinforcing agent. For illustrative purposes only, but not limiting the scope of the present invention thereby, for example, the dispersion method can be one or more of shaking, stirring, and ultrasonic-assisted mixing. In the actual operation process, various stirrers can be used for mixing, and an ultrasonic device can be used for assisted mixing, etc., to uniformly disperse the reinforcing agent in the coke-drawing medium.

[0054] According to a preferred embodiment of the present invention, the coke-drawing medium includes at least two of a naphtha fraction, a diesel fraction, and a wax oil fraction. In the coke-drawing medium, the content of any one of the naphtha fraction, the diesel fraction, or the wax oil fraction is 4 - 96 wt%. By adopting the foregoing technical solution, the prepared needle coke has advantages such as higher strength, lower thermal expansion coefficient, and higher electrical conductivity.

[0055] In the present invention, in the method for preparing needle coke, the coke-drawing medium having the foregoing composition can all achieve the purpose of the present invention. There are no special requirements for the properties of the coke-drawing medium such as the naphtha fraction, the diesel fraction, and the wax oil fraction. The following is for illustrative purposes only, but not limiting the scope of the present invention thereby. According to a preferred embodiment of the present invention, the 5% distillation temperature of the naphtha fraction is 40°C - 70°C, and the 95% distillation temperature of the naphtha fraction is 150°C - 190°C.

[0056] In the present invention, in the method for preparing needle coke, according to a preferred embodiment of the present invention, the 5% distillation temperature of the diesel fraction is 190°C - 240°C, and the 95% distillation temperature of the diesel fraction is 300°C - 350°C.

[0057] In the present invention, in the preparation method of needle coke, according to a preferred embodiment of the present invention, the 5% distillation temperature of the wax oil fraction is 250°C - 300°C, and the 95% distillation temperature of the wax oil fraction is 380°C - 420°C.

[0058] In the present invention, in the preparation method of needle coke, the pulling coke medium having the foregoing technical features can all achieve the purpose of the present invention. Those skilled in the art know that the pulling coke medium from the coking reaction system is generally fractionated from the coking reaction separation oil generated during the reaction process, including top rich gas, coker naphtha, coker diesel, coker wax oil, etc.; among them, the fractionation conditions of the coking reaction separation oil do not affect the properties of the prepared needle coke, and the fractionation conditions can be operated according to the prior art. For example, the fractionation conditions include: the bottom temperature of the tower is 300°C - 380°C, the top temperature of the tower is 100°C - 130°C, and the pressure is: 0.1 MPa - 0.25 MPa; the side line extraction temperature of fractions such as coker naphtha, coker diesel, and coker wax oil can be operated according to the prior art, and the present invention will not elaborate.

[0059] In the present invention, in the preparation method of needle coke, the externally introduced pulling coke medium includes naphtha fraction, gasoline fraction, kerosene fraction, diesel fraction, wax oil fraction, gaseous hydrocarbons with 1 - 3 carbon atoms (methane, ethane, butane), inert gases (nitrogen, argon, carbon dioxide, etc.), water (steam), etc. In the embodiments of the present invention, the advantages of the present invention are demonstrated by taking the pulling coke medium selected from the substances in the coking reaction system (coker naphtha + coker diesel + coker wax oil) and / or externally introduced substances (diesel fraction, gasoline fraction) as examples, but the scope of the present invention is not limited thereby.

[0060] In the present invention, in the preparation method of needle coke, for the gas stream containing a reinforcing agent, the mass ratio range of the reinforcing agent to the pulling coke medium is relatively wide. One embodiment is demonstrated as an example, but the scope of the present invention is not limited thereby. According to a preferred embodiment of the present invention, in the gas stream containing a reinforcing agent, the mass ratio of the reinforcing agent to the pulling coke medium is 1:100 - 1:5000. By adopting the foregoing technical solution, the prepared needle coke has advantages such as higher strength, lower thermal expansion coefficient, and higher electrical conductivity.

[0061] In the present invention, in the preparation method of needle coke, the mass ratio range of the amount of the pulling coke medium to the coking raw material is relatively wide. One embodiment is demonstrated as an example, but the scope of the present invention is not limited thereby. According to a preferred embodiment of the present invention, the mass ratio of the amount of the pulling coke medium to the coking raw material is 1:0.2 - 3. By adopting the foregoing technical solution, the prepared needle coke has advantages such as higher strength, lower thermal expansion coefficient, and higher electrical conductivity.

[0062] In the present invention, the coking raw materials undergo cracking reactions under high temperature and appropriate pressure. Heavy hydrocarbon molecules such as alkanes, cycloalkanes, and aromatic hydrocarbons are cracked into smaller molecules, such as reaction oil and gas composed of olefins, hydrogen, tar, etc. In addition, as the cracking reaction proceeds, intermediate products such as asphaltenes and resins begin to form mesophases. These mesophases undergo a series of chemical reactions such as dehydrogenation and condensation at high temperature, and gradually form unstable mesophase spheres.

[0063] In the method for preparing needle coke in the present invention, under the action of the coke-drawing gas flow, the unstable mesophase spheres undergo stacking and orientation to form the initial structure of needle coke. Aromatic molecules are oriented in the direction of the gas flow to form the needle-shaped structure of needle coke. The optional range of conditions for the coke-drawing and coking reactions is relatively wide. The following is a demonstration, but it does not limit the scope of the present invention. According to a preferred embodiment of the present invention, the conditions for the coke-drawing and coking reactions include: the superficial gas velocity of the coke-drawing gas flow is 0.01 m / s - 0.3 m / s, preferably 0.05 m / s - 0.2 m / s.

[0064] According to a preferred embodiment of the present invention, the conditions for the coke-drawing and coking reactions include: the temperature is 480°C - 620°C.

[0065] According to a preferred embodiment of the present invention, the conditions for the coke-drawing and coking reactions include: the pressure is 0.2 MPa - 1.2 MPa.

[0066] According to a preferred embodiment of the present invention, the conditions for the coke-drawing and coking reactions include: the time is 1 h - 48 h. By adopting the foregoing technical solution, the prepared needle coke has advantages such as higher strength, lower thermal expansion coefficient, and higher electrical conductivity.

[0067] In the method for preparing needle coke in the present invention, the optional range of conditions for the mesophase growth reaction is relatively wide. The following is a demonstration, but it does not limit the scope of the present invention. According to a preferred embodiment of the present invention, the conditions for the mesophase growth reaction include: the temperature is 420°C - 560°C.

[0068] According to a preferred embodiment of the present invention, the conditions for the mesophase growth reaction include: the pressure is 0.2 MPa - 1.2 MPa.

[0069] According to a preferred embodiment of the present invention, the conditions for the mesophase growth reaction include: the time is 1 - 48 h. By adopting the foregoing technical solution, the prepared needle coke has advantages such as higher strength, lower thermal expansion coefficient, and higher electrical conductivity.

[0070] In the present invention, in order to transfer the needle coke product out of the reaction system and prepare for the next coking reaction, after the coking reaction is completed, it generally also includes steam purging and decoking operations, which can be carried out according to the existing technology in the art, and the present invention will not elaborate on this.

[0071] In the present invention, common coking raw materials can be used in the present invention. The following is a demonstration but does not limit the scope of the present invention. For example, the coking raw materials include one or more of catalytic slurry oil, residue oil, tar, crude oil, fuel oil, and asphalt. In the embodiments of the present invention, the advantages of the present invention are demonstrated by taking the coking raw materials selected from one or more of catalytic slurry oil, vacuum residue, and ethylene tar, but this does not limit the scope of the present invention.

[0072] In the present invention, there are no special requirements for the composition of the coking raw materials. The following is a demonstration but does not limit the scope of the present invention. According to a preferred embodiment of the present invention, the density of the coking raw material is 0.8 g / cm 3 -1.1 g / cm 3 .

[0073] Those skilled in the art know that ash refers to the impurities that are not completely burned in the coke during the coking reaction, such as minerals, etc. According to a preferred embodiment of the present invention, the ash content of the coking raw material is 2 ppm - 150 ppm.

[0074] Those skilled in the art know that the four components of the coking raw material refer to four components: saturates, aromatics, resins, and asphaltenes. According to a preferred embodiment of the present invention, among the four components of the coking raw material, the content of saturates is 10 wt% - 55 wt%.

[0075] According to a preferred embodiment of the present invention, among the four components of the coking raw material, the content of aromatics is 20 wt% - 60 wt%.

[0076] According to a preferred embodiment of the present invention, among the four components of the coking raw material, the content of resins is 10 wt% - 60 wt%.

[0077] According to a preferred embodiment of the present invention, among the four components of the coking raw material, the content of asphaltenes is 0.05 wt% - 5 wt%.

[0078] The schematic diagram of the technical route of the present invention is as Figure 1 shown. The coking raw material is subjected to a coking reaction to obtain coking reaction separated oil. The reinforcing agent is uniformly dispersed in the coking reaction separated oil to obtain a composite coking medium. The composite coking medium is input into the reaction system in the coking stage of the coking reaction, and high-strength needle coke is obtained after coking.

[0079] In the present invention, the coking reaction device can be various devices capable of completing the coking reaction, such as an intermittent coking device, a delayed coking device, etc. The following is a demonstration, but it does not limit the scope of the present invention. For example, the coking reaction device includes 1 coke drum (reactor), that is, the place where the coking reaction (mesophase growth reaction, coke pulling - coke forming reaction) occurs and the needle coke product is produced; the coking reaction device can adopt an intermittent coking device with a single heating furnace and a coke drum (reactor), or a continuous device (two - furnace three - tower form) composed of 2 feed heating furnaces, 3 coke drums (reactors) and 1 fractionating tower, as well as necessary liquid conveying components, or a continuous device (one - furnace two - tower form) composed of 1 feed heating furnace, 2 coke drums (reactors) and 1 fractionating tower, and necessary liquid conveying components, etc. The advantages of the present invention are demonstrated by taking the coking reaction device in the two - furnace three - tower form as an example in the embodiments of the present invention. The device flow chart is as Figure 2 shown. The device in this embodiment can be operated singly (using any one of coke drum A, coke drum B and coke drum C) or continuously (using coke drum A, coke drum B and coke drum C). For any one of the 3 coke drums, the feed can be switched to raw oil slurry or composite coke - pulling medium. During continuous operation, when raw oil slurry is fed into coke drum A, coke drum B and coke drum C can perform composite medium coke - pulling operation or decoking operation. The advantages of the present invention are demonstrated by taking the single - operation (using coke drum A) as an example in the embodiments of the present invention.

[0080] The present invention provides needle coke prepared by the method described in the present invention.

[0081] The properties such as the strength, thermal expansion coefficient and conductivity of the needle coke prepared by the method described in the present invention have a relatively wide optional range. A demonstration of one implementation mode is given, but it does not limit the scope of the present invention. According to a preferred implementation mode of the present invention, the strength of the needle coke prepared by the method described in the present invention is 24% - 28%, the thermal expansion coefficient is 0.9×10 -6 / ℃ - 1.1×10 -6 / ℃, and the conductivity is 1900 S / m - 3000 S / m.

[0082] The beneficial effects of the present invention are as follows:

[0083] First, improve the strength of the needle coke:

[0084] The reinforcing agent is embedded between the needle - shaped structures of the needle coke, which can enhance the force between the needle - shaped structures - reinforcing agent - needle - shaped structures of the needle coke, thereby enhancing the strength of the needle coke;

[0085] Second, reduce the thermal expansion coefficient of the needle coke:

[0086] 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, enabling the needle coke to have a lower coefficient of thermal expansion;

[0087] Third, improve the electrical conductivity of the needle coke:

[0088] The reinforcing agent is embedded between the needle-shaped structures of the needle coke. While improving the strength of the needle coke, it also enhances the electrical conductivity between the needle-shaped structures, thereby enhancing the electrical conductivity of the needle coke;

[0089] Fourth, improve the thermal conductivity of the needle coke:

[0090] 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 having a higher thermal conductivity.

[0091] The present invention will be described in detail below through examples.

[0092] Testing methods for the properties of coking raw materials:

[0093] The density is measured by the method of GB / T 1884-1992 "Determination of Density of Petroleum and Liquid Petroleum Products (Hydrometer Method)";

[0094] The ash content is measured by the method of GB / T 508 "Determination of Ash Content of Petroleum Products";

[0095] The contents of four components: saturates, aromatics, resins, and asphaltenes are measured by the method of NBSHT 0509-2010 "Determination Method for Four Components of Petroleum Asphalt";

[0096] The distillation ranges (5% distillation temperature, 95% distillation temperature, etc.) of naphtha fraction, diesel fraction, and wax oil fraction are measured by the method in ASTM D1160;

[0097] The strength and coefficient of thermal expansion of the needle coke: The tests are carried out using a CTE tester and an automatic strength tester. The CTE test refers to the sample preparation standard of GB3074.4-2016, and the strength test refers to the standard of T / ZGS002-2019.

[0098] The electrical conductivity of the needle coke: The powder resistivity method is adopted, and the test is completed using the FT-301A type powder resistivity / compacted density meter of Ningbo Ruike Micro Intelligence Co., Ltd.

[0099] In the needle coke, the calculation method of the mass ratio of the reinforcing agent to the coke is as follows: In a reaction cycle, the feed mass is M1, the mass of the added reinforcing agent is M2, and the mass of the high-strength coke product generated is M3 (M3 includes M2). Then the mass ratio of the reinforcing agent to the coke = M3 / M2, and the mass ratio of the reinforcing agent to the raw material = M2 / M1.

[0100] The coking raw material 1 used in the embodiments of the present invention is filtered catalytic slurry oil, collected from Jinzhou Petrochemical Company, PetroChina; the coking raw material 2 is vacuum residue, collected from Liaohe Branch Company, PetroChina; the coking raw material 3 is ethylene tar, collected from Liaoyang Branch Company, PetroChina; the main properties and components of the three raw materials are shown in Table 1.

[0101] Table 1

[0102] Property Catalytic slurry oil (Raw material 1) Vacuum residue (Raw material 2) Ethylene tar (Raw material 3) Density (20°C) <![CDATA[1.0624g / cm 3 > <![CDATA[0.918g / cm 3 > <![CDATA[0.982g / cm 3 > Ash content 75 ppm 18 ppm 6 ppm Four components Content wt% Content wt% Content wt% Saturates 22.8 49.6 15.7 Aromatics 58.1 28.6 28.5 Resins 17.0 21.7 54.6 Asphaltenes 2.1 0.1 1.2

[0103] The coking media used in the embodiments and comparative examples of the present invention are naphtha fraction, diesel fraction and wax oil fraction from the coking reaction system; as well as externally-supplied diesel fraction (externally-supplied medium 1) collected from Jinzhou Branch Company, PetroChina and externally-supplied gasoline fraction (externally-supplied medium 2) collected from Daqing Branch Company, PetroChina: the main properties and main components of the externally-supplied diesel fraction (externally-supplied medium 1) and the externally-supplied gasoline fraction (externally-supplied medium 2) are shown in Table 2; the main properties and main components of the 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 such as the distillation range and main components of the naphtha fraction, diesel fraction and wax oil fraction from the coking reaction system in Examples 2-12 are similar to those in Example 1.

[0104] Table 2

[0105]

[0106]

[0107] Graphene: Prepared by exfoliating graphite, the number of carbon atom layers of graphene is: 80% with 1 layer, 20% with 2 layers, and the size of graphene (equivalent diameter of the sheet size of graphene) is 30 ± 10 μm;

[0108] Graphite: Graphite with the number of carbon atom layers exfoliated to be: 60% with 3-4 layers, 40% with 5-6 layers, and the size (equivalent diameter of the sheet size of graphene) is 50 ± 10 μm;

[0109] 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.);

[0110] Carbon fiber A: Commercially available 24k carbon fiber, without sizing treatment, tensile modulus of 230 GPa, single filament diameter of 8 μm, pulverized, and the single filament length of the powder after treatment is 100 ± 20 μm.

[0111] Carbon fiber B: Commercially available 24k carbon fiber, without sizing treatment, tensile modulus of 230 GPa, single filament diameter of 8 μm, pulverized, and the single filament length of the powder after treatment is 8 ± 1 μm.

[0112] Example 1

[0113] Using catalytic slurry as raw material, the properties are shown in Table 1. 100 kg of catalytic slurry (Raw material 1) is heated by Furnace A and then enters the coking tower for reaction. The reaction time is 18 h, and the temperature of Furnace A is controlled at 460 - 480 °C. During the reaction, the pressure at the top of the coking tower is 0.45 - 0.5 MPa. All the oil and gas generated by the reaction enter the fractionating tower. The bottom temperature of the tower is 350 - 360 °C, the top temperature is 100 - 110 °C, and the pressure of the fractionating tower is 0.15 - 0.2 MPa. The coking reaction separated oil is separated, including coker naphtha, coker diesel, and coker wax oil. 10 kg of coker naphtha, 10 kg of coker diesel, 16 kg of coker wax oil, and 14 kg of externally-supplied naphtha (Externally-supplied medium 2) are taken and added to the mixing tank; 0.01 kg of reinforcing agent graphene is added to the mixing tank. The coking medium mixing tank is stirred and mixed. The mixed composite coking medium is heated by Furnace B and pumped into the coking tower by a pump for coking. The temperature of Furnace B is controlled at 570 - 590 °C, the pressure at the top of the coking tower is 0.45 - 0.5 MPa, the empty tower linear velocity in the tower is 0.09 - 0.11 m / s, and the coking duration is 18 h. After coking, the coking tower is purged with steam and decoked to obtain 48.26 kg of needle coke. The strength, thermal expansion coefficient, conductivity of the obtained needle coke, and the content of the reinforcing agent in the needle coke are shown in Table 3.

[0114] Example 2

[0115] Using catalytic slurry as raw material, the properties are shown in Table 1. 100 kg of catalytic slurry (Raw material 1) is heated by Furnace A and then enters the coking tower for reaction. The reaction time is 24 h, and the temperature of Furnace A is controlled at 420 - 440 °C. During the reaction, the pressure at the top of the coking tower is 0.6 - 0.65 MPa. All the oil and gas generated by the reaction enter the fractionating tower. The bottom temperature of the tower is 350 - 360 °C, the top temperature is 100 - 110 °C, and the pressure of the fractionating tower is 0.15 - 0.2 MPa. The coking reaction separated oil is separated, including coker naphtha, coker diesel, and coker wax oil. 8 kg of coker naphtha, 15 kg of coker diesel, and 150 kg of externally-supplied diesel (Externally-supplied medium 1) are taken and added to the mixing tank; 0.04 kg of reinforcing agent carbon nanotubes is added to the mixing tank. The coking medium mixing tank is stirred and mixed. The mixed composite coking medium is heated by Furnace B and pumped into the coking tower by a pump for coking. The temperature of Furnace B is controlled at 490 - 510 °C, the pressure at the top of the coking tower is 0.6 - 0.65 MPa, the empty tower linear velocity in the tower is 0.11 - 0.13 m / s, and the coking duration is 24 h. After coking, the coking tower is purged with steam and decoked to obtain 46.17 kg of needle coke. The strength, thermal expansion coefficient, conductivity of the obtained needle coke, and the content of the reinforcing agent in the needle coke are shown in Table 3.

[0116] Example 3

[0117] Using catalytic slurry as raw material, the properties are shown in Table 1. 100 kg of catalytic slurry (Raw material 1) is heated by Furnace A and then enters the coke drum for reaction. The reaction time is 24 h, and the temperature of Furnace A is controlled at 420 - 440 °C. During the reaction, the pressure at the top of the coke drum is 0.6 - 0.65 MPa. All the oil and gas generated by the reaction enter the fractionating tower. The bottom temperature of the tower is 350 - 360 °C, the top temperature is 100 - 110 °C, and the pressure of the fractionating tower is 0.15 - 0.2 MPa. The coking reaction separated oil is separated, including coker naphtha, coker diesel, and coker wax oil. 8 kg of coker naphtha, 15 kg of coker diesel, and 150 kg of externally-supplied diesel (Externally-supplied medium 1) are taken and added to the mixing tank. The reinforcing agents carbon nanotubes and graphene are added to the mixing tank, with the added amounts being 0.035 kg of carbon nanotubes and 0.005 kg of graphene. The mixing tank for the coke-drawing medium is stirred and mixed. The mixed composite coke-drawing medium is heated by Furnace B and pumped into the coke drum for coke-drawing by a pump. The temperature of Furnace B is controlled at 490 - 510 °C, the pressure at the top of the coke drum is 0.6 - 0.65 MPa, the superficial velocity in the empty tower inside the tower is 0.11 - 0.13 m / s, and the coke-drawing duration is 24 h. After the coke-drawing is completed, the coke drum is purged with steam and decoked to obtain 45.87 kg of needle coke. The strength, thermal expansion coefficient, conductivity of the obtained needle coke, and the content of the reinforcing agent in the needle coke are shown in Table 3.

[0118] Example 4

[0119] Using vacuum residue as raw material, the properties are shown in Table 1. 100 kg of catalytic slurry (Raw material 2) is heated by Furnace A and then enters the coke drum for reaction. The reaction time is 8 h, and the temperature of Furnace A is controlled at 480 - 520 °C. During the reaction, the pressure at the top of the coke drum is 0.85 - 0.9 MPa. All the oil and gas generated by the reaction enter the fractionating tower. The bottom temperature of the tower is 350 - 360 °C, the top temperature is 100 - 110 °C, and the pressure of the fractionating tower is 0.15 - 0.2 MPa. The coking reaction separated oil is separated, including coker naphtha, coker diesel, and coker wax oil. 15 kg of coker naphtha, 15 kg of coker diesel, 15 kg of coker wax oil, and 5 kg of externally-supplied naphtha (Externally-supplied medium 2) are taken and added to the mixing tank. The reinforcing agent graphite is added to the mixing tank, with the added amount being 0.1 kg. The mixing tank for the coke-drawing medium is stirred and mixed. The mixed composite coke-drawing medium is heated by Furnace B and pumped into the coke drum for coke-drawing by a pump. The temperature of Furnace B is controlled at 530 - 550 °C, the pressure at the top of the coke drum is 0.85 - 0.9 MPa, the superficial velocity in the empty tower inside the tower is 0.09 - 0.11 m / s, and the coke-drawing duration is 8 h. After the coke-drawing is completed, the coke drum is purged with steam and decoked to obtain 45.04 kg of needle coke. The strength, thermal expansion coefficient, conductivity of the obtained needle coke, and the content of the reinforcing agent in the needle coke are shown in Table 3.

[0120] Example 5

[0121] Using catalytic slurry and vacuum residue as raw materials, the properties are shown in Table 1. 70 kg of catalytic slurry (raw material 1) and 30 kg of vacuum residue (raw material 2) are heated by heating furnace A and then enter the coking tower for reaction. The reaction time is 48 h, and the temperature of the heating furnace is controlled at 520 - 560 °C. During the reaction process, the pressure at the top of the coking tower is 0.65 - 0.7 MPa. All the oil and gas generated by the reaction enter the fractionating tower. The bottom temperature of the tower is 350 - 360 °C, the top temperature of the tower is 100 - 110 °C, and the pressure of the fractionating tower is 0.15 - 0.2 MPa. The coking reaction separated oil is separated out, including coker naphtha, coker diesel, and coker wax oil. 15 kg of coker naphtha, 15 kg of coker diesel, 15 kg of coker wax oil, and 5 kg of externally supplemented naphtha (externally supplemented medium 2) are taken and added to the mixing tank; 0.4 kg of reinforcing agent carbon fiber A is added to the mixing tank. The coking medium mixing tank is stirred and mixed. The mixed composite coking medium is heated by heating furnace B and pumped into the coking tower by a pump for coking. The temperature of the heating furnace is controlled at 590 - 610 °C, the pressure at the top of the coking tower is 0.65 - 0.7 MPa, the empty tower linear velocity in the tower is 0.13 - 0.15 m / s, and the coking duration is 48 h. After the coking is completed, the coking tower is purged with steam and decoked to obtain 45.56 kg of needle coke. The strength, thermal expansion coefficient, electrical conductivity of the obtained needle coke, and the content of the reinforcing agent in the needle coke are shown in Table 3.

[0122] Example 6

[0123] Using catalytic slurry and ethylene tar as raw materials, the properties are shown in Table 1. 80 kg of catalytic slurry (raw material 1) and 20 kg of ethylene tar (raw material 3) are heated by heating furnace A and then enter the coking tower for reaction. The reaction time is 18 h, and the temperature of the heating furnace is controlled at 480 - 500 °C. During the reaction process, the pressure at the top of the coking tower is 0.5 - 0.6 MPa. All the oil and gas generated by the reaction enter the fractionating tower. The bottom temperature of the tower is 350 - 360 °C, the top temperature of the tower is 100 - 110 °C, and the pressure of the fractionating tower is 0.15 - 0.2 MPa. The coking reaction separated oil is separated out, including coker naphtha, coker diesel, and coker wax oil. 10 kg of coker naphtha, 10 kg of coker diesel, 2 kg of coker wax oil, and 28 kg of externally supplemented diesel (externally supplemented medium 1) are taken and added to the mixing tank; 0.01 kg of reinforcing agent graphene is added to the mixing tank. The coking medium mixing tank is stirred and mixed. The mixed composite coking medium is heated by heating furnace B and pumped into the coking tower by a pump for coking. The temperature of the heating furnace is controlled at 580 - 600 °C, the pressure at the top of the coking tower is 0.5 - 0.6 MPa, the empty tower linear velocity in the tower is 0.08 - 0.09 m / s, and the coking duration is 18 h. After the coking is completed, the coking tower is purged with steam and decoked to obtain 44.12 kg of needle coke. The strength, thermal expansion coefficient, electrical conductivity of the obtained needle coke, and the content of the reinforcing agent in the needle coke are shown in Table 3.

[0124] Example 7

[0125] Using catalytic slurry as raw material, the properties are shown in Table 1. 100 kg of catalytic slurry (Raw material 1) is heated by Heating Furnace A and then enters the coke drum for reaction. The reaction time is 18 h, and the temperature of the heating furnace is controlled at 460 - 480 °C. During the reaction process, the pressure at the top of the coke drum is 0.45 - 0.5 MPa. Take 50 kg of externally-supplied naphtha (Externally-supplied medium 2) and add it to the mixing tank; add 0.01 kg of the reinforcing agent graphene to the mixing tank. The mixing tank for the coke pulling medium is stirred and mixed. The mixed composite coke pulling medium is heated by Heating Furnace B and pumped into the coke drum by a pump for coke pulling. The temperature of the heating furnace is controlled at 570 - 590 °C, the pressure at the top of the coke drum is 0.45 - 0.5 MPa, the empty tower linear velocity in the tower is 0.09 - 0.11 m / s, and the coke pulling duration is 18 h. After the coke pulling is completed, the coke drum is purged with steam and decoked to obtain 48.07 kg of needle coke. The strength, thermal expansion coefficient, conductivity of the obtained needle coke, and the content of the reinforcing agent in the needle coke are shown in Table 3.

[0126] Example 8

[0127] Using catalytic slurry and vacuum residue as raw materials, the properties are shown in Table 1. 70 kg of catalytic slurry (Raw material 1) and 30 kg of vacuum residue (Raw material 2) are heated by Heating Furnace A and then enter the coke drum for reaction. The reaction time is 48 h, and the temperature of the heating furnace is controlled at 520 - 560 °C. During the reaction process, the pressure at the top of the coke drum is 0.65 - 0.7 MPa. All the oil and gas generated by the reaction enter the fractionating tower. The bottom temperature of the tower is 350 - 360 °C, the top temperature of the tower is 100 - 110 °C, and the pressure of the fractionating tower is 0.15 - 0.2 MPa. The coking reaction separation oil is separated out, including coker naphtha, coker diesel, and coker wax oil. Take 15 kg of coker naphtha, 15 kg of coker diesel, 15 kg of coker wax oil, and 5 kg of externally-supplied naphtha (Externally-supplied medium 2) and add them to the mixing tank; add 2 kg of the reinforcing agent carbon fiber A to the mixing tank. The mixing tank for the coke pulling medium is stirred and mixed. The mixed composite coke pulling medium is heated by Heating Furnace B and pumped into the coke drum by a pump for coke pulling. The temperature of the heating furnace is controlled at 590 - 610 °C, the pressure at the top of the coke drum is 0.65 - 0.7 MPa, the empty tower linear velocity in the tower is 0.13 - 0.15 m / s, and the coke pulling duration is 48 h. After the coke pulling is completed, the coke drum is purged with steam and decoked to obtain 47.24 kg of needle coke. The strength, thermal expansion coefficient, conductivity of the obtained needle coke, and the content of the reinforcing agent in the needle coke are shown in Table 3.

[0128] Example 9

[0129] Using catalytic slurry and vacuum residue as raw materials, the properties are shown in Table 1. 70 kg of catalytic slurry (raw material 1) and 30 kg of vacuum residue (raw material 2) are heated by furnace A and then enter the coking tower for reaction. The reaction time is 48 h, and the temperature of furnace A is controlled at 520 - 560 °C. During the reaction, the pressure at the top of the coking tower is 0.65 - 0.7 MPa. All the generated oil and gas enter the fractionating tower. The bottom temperature of the tower is 350 - 360 °C, the top temperature is 100 - 110 °C, and the pressure of the fractionating tower is 0.15 - 0.2 MPa. The coking reaction separation oil is separated, including coker naphtha, coker diesel, and coker wax oil. 15 kg of coker naphtha, 15 kg of coker diesel, 15 kg of coker wax oil, and 5 kg of externally supplemented naphtha (externally supplemented medium 2) are taken and added to the mixing tank; 0.4 kg of reinforcing agent carbon fiber B is added to the mixing tank. The coking medium mixing tank is stirred and mixed. The mixed composite coking medium is heated by furnace B and pumped into the coking tower by a pump for coking. The temperature of furnace B is controlled at 590 - 610 °C, the pressure at the top of the coking tower is 0.65 - 0.7 MPa, the empty tower linear velocity in the tower is 0.13 - 0.15 m / s, and the coking duration is 48 h. After coking, the coking tower is purged with steam and decoked to obtain 45.13 kg of needle coke. The strength, thermal expansion coefficient, conductivity of the obtained needle coke, and the content of the reinforcing agent in the needle coke are shown in Table 3.

[0130] Example 10

[0131] Using catalytic slurry as the raw material, the properties are shown in Table 1. 100 kg of catalytic slurry (raw material 1) is heated by furnace A and then enters the coking tower for reaction. The reaction time is 18 h, and the temperature of furnace A is controlled at 460 - 480 °C. During the reaction, the pressure at the top of the coking tower is 0.45 - 0.5 MPa. All the generated oil and gas enter the fractionating tower. The bottom temperature of the tower is 350 - 360 °C, the top temperature is 100 - 110 °C, and the pressure of the fractionating tower is 0.15 - 0.2 MPa. The coking reaction separation oil is separated, including coker naphtha, coker diesel, and coker wax oil. 10 kg of coker naphtha, 10 kg of coker diesel, 16 kg of coker wax oil, and 14 kg of externally supplemented naphtha (externally supplemented medium 2) are taken and added to the mixing tank; 0.01 kg of reinforcing agent graphene is added to the mixing tank. The coking medium mixing tank is stirred and mixed. The mixed composite coking medium is heated by furnace B and pumped into the coking tower by a pump for coking. The temperature of furnace B is controlled at 400 - 420 °C, the pressure at the top of the coking tower is 0.45 - 0.5 MPa, the empty tower linear velocity in the tower is 0.09 - 0.11 m / s, and the coking duration is 18 h. After coking, the coking tower is purged with steam and decoked to obtain 48.93 kg of needle coke. The strength, thermal expansion coefficient, conductivity of the obtained needle coke, and the content of the reinforcing agent in the needle coke are shown in Table 3.

[0132] Example 11

[0133] Using catalytic slurry as raw material, the properties are shown in Table 1. 100 kg of catalytic slurry (Raw material 1) is heated by Furnace A and then enters the coke tower for reaction. The reaction time is 18 h, and the temperature of Furnace A is controlled at 460 - 480 °C. During the reaction, the pressure at the top of the coke tower is 0.45 - 0.5 MPa. All the oil and gas generated by the reaction enter the fractionating tower. The bottom temperature of the tower is 350 - 360 °C, the top temperature is 100 - 110 °C, and the pressure of the fractionating tower is 0.15 - 0.2 MPa. The coking reaction separated oil is separated, including coker naphtha, coker diesel, and coker wax oil. 10 kg of coker naphtha, 10 kg of coker diesel, 16 kg of coker wax oil, and 14 kg of externally-supplied naphtha (Externally-supplied medium 2) are taken and added to the mixing tank. The reinforcing agent graphene is added to the mixing tank in an amount of 0.01 kg. The mixing tank for the coke-drawing medium is stirred and mixed. The mixed composite coke-drawing medium is heated by Furnace B and pumped into the coke tower for coke drawing by a pump. The temperature of Furnace B is controlled at 570 - 590 °C, the pressure at the top of the coke tower is 0.45 - 0.5 MPa, the empty tower linear velocity in the tower is 0.03 - 0.04 m / s, and the coke-drawing duration is 18 h. After the coke drawing is completed, the coke tower is purged with steam and decoked to obtain 48.78 kg of needle coke. The strength, thermal expansion coefficient, conductivity of the obtained needle coke, and the content of the reinforcing agent in the needle coke are shown in Table 3.

[0134] Example 12

[0135] Using catalytic slurry as raw material, the properties are shown in Table 1. 100 kg of catalytic slurry (Raw material 1) is heated by Furnace A and then enters the coke tower for reaction. The reaction time is 24 h, and the temperature of Furnace A is controlled at 420 - 440 °C. During the reaction, the pressure at the top of the coke tower is 0.6 - 0.65 MPa. All the oil and gas generated by the reaction enter the fractionating tower. The bottom temperature of the tower is 350 - 360 °C, the top temperature is 100 - 110 °C, and the pressure of the fractionating tower is 0.15 - 0.2 MPa. The coking reaction separated oil is separated, including coker naphtha, coker diesel, and coker wax oil. 8 kg of coker naphtha, 15 kg of coker diesel, and 150 kg of externally-supplied diesel (Externally-supplied medium 1) are taken and added to the mixing tank. The reinforcing agent carbon nanotubes are added to the mixing tank in an amount of 0.004 kg of carbon nanotubes. The mixing tank for the coke-drawing medium is stirred and mixed. The mixed composite coke-drawing medium is heated by Furnace B and pumped into the coke tower for coke drawing by a pump. The temperature of Furnace B is controlled at 490 - 510 °C, the pressure at the top of the coke tower is 0.6 - 0.65 MPa, the empty tower linear velocity in the tower is 0.11 - 0.13 m / s, and the coke-drawing duration is 24 h. After the coke drawing is completed, the coke tower is purged with steam and decoked to obtain 46.67 kg of needle coke. The strength, thermal expansion coefficient, conductivity of the obtained needle coke, and the content of the reinforcing agent in the needle coke are shown in Table 3.

[0136] Comparative Example 1

[0137] Same as Example 1, except that no reinforcing agent was added and other conditions were the same, and 48.91 kg of needle coke was obtained. The strength, coefficient of thermal expansion, electrical conductivity of the obtained needle coke, and the content of the reinforcing agent in the needle coke are shown in Table 3.

[0138] Comparative Example 2

[0139] Same as Example 1, except that the reinforcing agent was added to the raw material slurry and entered the reaction system together with the raw material slurry, rather than being input into the reaction system during the coke pulling stage, and other conditions were the same, and 48.55 kg of needle coke was obtained. The strength, coefficient of thermal expansion, electrical conductivity of the obtained needle coke, and the content of the reinforcing agent in the needle coke are shown in Table 3.

[0140] Comparative Example 3

[0141] Same as Example 3, except that the reinforcing medium was added to the raw material slurry and entered the reaction system together with the raw material slurry, rather than being input into the reaction system during the coke pulling stage, and other conditions were the same. 45.63 kg of needle coke was obtained. The strength, coefficient of thermal expansion, electrical conductivity of the obtained needle coke, and the content of the reinforcing agent in the needle coke are shown in Table 3.

[0142] Table 3

[0143]

[0144] It can be seen from the results in Table 3 that the strength of Examples 1-4 is higher than that of Comparative Example 1 due to the addition of the reinforcing medium during the coke pulling process; in Comparative Examples 2-3, adding the reinforcing medium to the raw materials has a worse effect than adding the reinforcing medium during the coke pulling process. It is speculated that mixing the reinforcing medium before the formation of the mesophase will instead affect the formation of the mesophase and cause a decrease in strength. Therefore, the best input time of the reinforcing medium is the coke pulling stage, and the reinforcing effect of the reinforcing medium can only be exerted by relying on the distribution and orientation of the coke pulling gas flow. Combining the results of Examples 1-12 and Comparative Examples 1-3, adopting the implementation scheme provided by the present invention can better improve the performance of needle coke.

[0145] 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 technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A needle coke, characterized in that, The needle coke contains a reinforcing agent, which is embedded between the needle-shaped structures of the needle coke. The strength of the needle coke is 24%-28%, the coefficient of thermal expansion is 0.9×10 -6 / °C - 1.1×10 -6 / °C, and the conductivity is 1900 S / m - 3000 S / m.

2. The needle coke according to claim 1, wherein, The conductivity of the needle coke is 1900 S / m - 2650 S / m.

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

4. The needle coke according to claim 1 or 2, wherein the reinforcing agent comprises one-dimensional carbon materials and / or two-dimensional carbon materials; along the axis or plane direction of the reinforcing agent, the equivalent diameter of the length or sheet size of the reinforcing agent is 0.2 μm - 200 μm; perpendicular to the axis or plane direction of the reinforcing agent, the diameter or thickness of the reinforcing agent is 0.2 nm - 15 μm.

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

6. The needle coke according to claim 4, wherein the two-dimensional carbon material is selected from graphene and / or graphite. along the plane direction of the two-dimensional carbon material, the equivalent diameter of the sheet size of the two-dimensional carbon material is 20 μm - 100 μm; the number of carbon atom layers of the two-dimensional carbon material is 1 - 30 layers.

7. The needle coke according to claim 1 or 2, wherein the reinforcing agent comprises one-dimensional carbon materials and two-dimensional carbon materials, and the content of each is not less than 10 wt%.

8. A method for preparing needle coke, characterized in that, The method comprises: (1) The coking raw material undergoes a mesophase growth reaction to form mesophase spheres; (2) In an air stream containing a reinforcing agent, the mesophase spheres undergo a coking - coke formation reaction; the mass ratio of the dosage of the reinforcing agent to the dosage of the coking raw material is 1:100 - 1:30000.

9. The method according to claim 8, wherein the reinforcing agent comprises one-dimensional carbon materials and / or two-dimensional carbon materials; along the axis or plane direction of the reinforcing agent, the equivalent diameter of the length or sheet size of the reinforcing agent is 0.2 μm - 200 μm; perpendicular to the axis or plane direction of the reinforcing agent, the diameter or thickness of the reinforcing agent is 0.2 nm - 15 μm.

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

11. The method according to claim 9, wherein the two-dimensional carbon material is selected from graphene and / or graphite; along the plane direction of the two-dimensional carbon material, the equivalent diameter of the sheet size of the two-dimensional carbon material is 20 μm - 100 μm; the number of carbon atom layers of the two-dimensional carbon material is 1 - 30 layers.

12. The method according to claim 8 or 9, wherein The reinforcing agent includes one-dimensional carbon materials and two-dimensional carbon materials, and the content of each is not less than 10 wt%.

13. The method according to claim 8 or 9, wherein the reinforcing agent is dispersed in the coking medium to form the gas stream 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 - 3 carbon atoms, inert gas, and water.

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

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

16. The method according to claim 13, wherein 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 dosage of the coking raw material is 1:0.2 - 3.

17. The method according to any one of claims 8 - 11, wherein the conditions of the coking - coke formation reaction include: the superficial gas velocity of the coking gas stream is 0.01 m / s - 0.3 m / s; the temperature is 480°C - 620°C; the pressure is 0.2 MPa - 1.2 MPa; the time is 1 h - 48 h.

18. The method according to any one of claims 8 - 11, wherein the conditions of the mesophase growth reaction include: the temperature is 420°C - 560°C; the pressure is 0.2 MPa - 1.2 MPa; the time is 1 - 48 h.

19. The method according to any one of claims 8 - 11, wherein the coking raw material includes one or more of catalytic oil slurry, residue oil, tar, crude oil, fuel oil, and asphalt; The density of the coking raw material is 0.8 g / cm 3 - 1.1 g / cm 3 ; the ash content of the coking raw material is 2 ppm - 150 ppm; among the four components of the coking raw material, the content of the saturates is 10 wt% - 55 wt%, the content of the aromatics is 20 wt% - 60 wt%, the content of the resins is 10 wt% - 60 wt%, and the content of the asphaltenes is 0.05 wt% - 5 wt%.

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

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

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