Petroleum coke, non-graphitic carbon material, negative electrode material and preparation method thereof

Abstract

The invention discloses petroleum coke, a non-graphite carbon material, a negative electrode material and a preparation method thereof. The method comprises the following steps: performing first solid removal on a first heavy oil raw material to obtain first purified heavy oil; performing second solid removal on the second heavy oil raw material to obtain second purified heavy oil; mixing the second purified heavy oil with nano-porous carbon to obtain third purified heavy oil and heavy oil containing the nano-porous carbon; carrying out solid-liquid separation on the heavy oil containing the nano-porous carbon to obtain a non-graphite carbon material precursor and fourth purified heavy oil; mixing the third purified heavy oil, the fourth purified heavy oil and the first purified heavy oil to obtain heavy mixed oil; carrying out distillation, pyrolysis and modification treatment on the heavy mixed oil to obtain petroleum coke; carbonizing the non-graphite carbon material precursor to obtain a non-graphite carbon material; the negative electrode material is prepared from petroleum coke and a non-graphite carbon material. The petroleum coke and the non-graphite carbon material with relatively high quality are prepared, and the electrochemical performance of the negative electrode material can be improved.

Description

Petroleum coke, non-graphite carbon materials and anode materials and their preparation methods Technical Field

[0001] This invention relates to petroleum coke, non-graphite carbon materials, and anode materials and their preparation methods, belonging to the field of anode material technology. Background Technology

[0002] Currently, the anode materials used in commercial lithium-ion batteries mainly include carbon materials and non-carbon materials. Carbon materials include graphite, which is currently the most widely used, as well as disordered carbon materials, hard carbon materials, and soft carbon materials. Graphite includes two main categories: artificial graphite and natural graphite. Artificial graphite is produced by graphitizing easily graphitizable carbon (such as petroleum coke, needle coke, or pitch coke) at high temperatures of 2800–3000℃ in an N2 atmosphere. Natural graphite includes amorphous graphite and flake graphite. Natural graphite has a slightly higher capacity than artificial graphite, while artificial graphite has better cycle performance than natural graphite. Due to the advantages of artificial graphite, such as high conductivity, relatively low price, and low ash content, as well as its sufficiently high lithium insertion / extraction capacity and good lithium extraction / deintercalation reversibility to ensure high voltage, large capacity, long cycle life, and current density requirements, artificial graphite anode materials have become the mainstream product in the anode material market in recent years.

[0003] Generally, high-specific-capacity artificial graphite anode materials use needle coke as raw material, while ordinary-specific-capacity anode materials use inexpensive petroleum coke. The choice of raw material has a significant impact on the performance of artificial graphite anode materials, affecting their specific capacity, cycle life, rate capability, and compaction density. Existing low-cost ordinary petroleum coke is difficult to replace needle coke as a raw material for high-specific-capacity artificial graphite. This is because petroleum coke is obtained by passing heavy oil (from crude oil distillation) or other heavy oils at high flow rates through the furnace tubes of a 500°C heating furnace, where cracking and condensation reactions occur within a coke tower, followed by cooling and decoking. Due to the significant differences in the chemical molecular structure of heavy oils obtained from different crude oil sources and processing methods, and the presence of metallic impurities and asphaltenes in the heavy oil, the formation of the ordered structure of the petroleum coke is affected, thus impacting the capacity performance of the artificial graphite anode materials prepared from it. Furthermore, the solid-phase coating technology commonly used in the preparation of artificial graphite anode materials is costly and has poor coating uniformity, and the types and sources of existing coating agents are limited.

[0004] CN114456841A discloses petroleum coke and its preparation method, as well as a carbon anode material and its preparation method. The method involves heating a low-quality raw material to 360–390°C for vacuum distillation to obtain light non-ideal components, heavy non-ideal components, and a fraction with a distillation range of 350–500°C. The 350–500°C fraction is then hydrorefined with hydrogen in the presence of a hydrorefining catalyst. The resulting product is then thermally cracked to obtain petroleum coke with a sulfur content <0.5 wt% and an ash content <0.3 wt%. This petroleum coke is then subjected to heat treatment and graphitization to obtain a carbon anode material. This carbon anode material has an initial discharge specific capacity ≥350 mAh / g and an initial coulombic efficiency ≥90%. However, it is difficult for this petroleum coke-based graphite anode material to exceed the capacity requirement of 360 mAh / g.

[0005] CN118360080A discloses a method for producing battery-grade anode material feedstock from heavy fuel oil. The method includes: feeding an oil-gas mixture from a fixed-bed hydrotreating process into a medium-pressure stripping tower for gas-liquid separation; the gas phase, along with the cold low-pressure oil from the cold low-pressure fractionation tank, entering the coking fractionation tower from the middle section; the liquid phase, after being heated in a furnace, entering the coking fractionation tower from the middle section; and loading a hydrodesulfurization catalyst into the low-temperature hydrotreating section at the top of the fixed-bed reactor; the catalyst dosage is 0.4-1 cm³. 3 / kg; The bottom oil from the heating furnace is fed into the lower part of the coking tower for treatment, and the oil and gas enter from the bottom of the coking fractionation tower to achieve circulation; the gas phase at the top of the coking fractionation tower is separated into gas and liquid phases in a buffer tank, and the liquid phase is returned to the coking fractionation tower via a second circulation pump; part of the coking circulating oil at the bottom of the coking fractionation tower is sent to the heating furnace via a feed pump for delayed coking reaction; part is heated by the first circulation pump and steam generator, and then returned to the coking fractionation tower; the high-quality, low-sulfur, low-ash petroleum coke produced by the coking fractionation tower can be used to produce battery-grade anode materials. However, this literature only explored the sulfur content of the obtained petroleum coke, and did not further study the utilization of the liquid phase oil components, the influence of the coking process on the structure of the anode material raw materials, and thus the impact on the electrochemical performance of the anode.

[0006] CN112490443A discloses a liquid-phase coated graphite anode material and its preparation method. The method includes the following steps: thermally stirring petroleum coke, then graphitizing the thermally stirred petroleum coke to obtain graphitized recycled material; mixing the graphitized recycled material with liquid phenolic resin until uniform, and then carbonizing to obtain the liquid-phase coated graphite anode material. This method improves the rate performance of the liquid-phase coated graphite anode material and ensures uniform coating. However, the highest initial discharge capacity of lithium-ion batteries prepared using this liquid-phase coated graphite anode material is 354.6 mAh / g, failing to exceed the capacity requirement of 360 mAh / g.

[0007] Therefore, existing technologies suffer from problems such as poor quality of petroleum coke produced from heavy oil, poor coating effect of artificial graphite materials, difficulty in fully utilizing heavy oil, and the need to further improve the performance of anode materials. Summary of the Invention

[0008] To address at least one of the aforementioned technical problems, the present invention aims to provide petroleum coke, non-graphite carbon materials, and anode materials, as well as methods for their preparation. The present invention can prepare high-quality petroleum coke and non-graphite carbon materials, thereby improving the electrochemical performance of the anode material.

[0009] To achieve the above objectives, the first aspect of the present invention provides a method for preparing petroleum coke, non-graphite carbon materials, and anode materials, comprising the following steps:

[0010] (1) The first heavy oil raw material is subjected to a first desolidification treatment to obtain a first purified heavy oil; the second heavy oil raw material is subjected to a second desolidification treatment to obtain a second purified heavy oil;

[0011] (2) The second purified heavy oil is mixed with nanoporous carbon to obtain the third purified heavy oil in the upper layer and the heavy oil containing nanoporous carbon in the lower layer.

[0012] (3) The heavy oil containing nanoporous carbon is subjected to solid-liquid separation to obtain a non-graphite carbon material precursor and a fourth purified heavy oil.

[0013] (4) The third purified heavy oil, the fourth purified heavy oil and the first purified heavy oil are mixed to obtain a heavy mixed oil;

[0014] (5) The heavy mixed oil is distilled to obtain coking mixed oil;

[0015] (6) The coking mixture is pyrolyzed to obtain petroleum coke precursor;

[0016] (7) Modify the petroleum coke precursor to obtain the petroleum coke;

[0017] (8) Carbonize the non-graphite carbon material precursor to obtain the non-graphite carbon material.

[0018] (9) Anode materials are prepared using the petroleum coke and the non-graphite carbon material.

[0019] According to a specific embodiment of the present invention, preferably, in step (1), based on the total mass of the first heavy oil feedstock as 100%, the content of saturated fraction is 10-17%, the content of aromatic fraction is 55-75%, the content of gum is 10-18%, the content of asphaltenes is 1-10%, the content of sulfur is 0.3-1.2%, the content of nitrogen is 0.1-0.5%, and the content of residual carbon is 13-20%; the density of the first heavy oil feedstock at 20°C is 0.97-1.04 g / cm³. 3 The dynamic viscosity at 130℃ is 0.3–0.4 Pa·s; and the ash content of the first heavy oil feedstock is 2000–5000 ppm. Specifically, the first heavy oil feedstock includes, but is not limited to, one or more of the following: catalytic cracking slurry oil, coking wax oil, thermal cracking residue oil, hydrotreated tail oil, furfural extract oil, reformed heavy aromatic oil, and vacuum distillate oil.

[0020] According to a specific embodiment of the present invention, preferably, in step (1), the first deconsolidation treatment includes one or both of sedimentation deconsolidation and electric field deconsolidation. More preferably, the first deconsolidation treatment includes electric field deconsolidation, or includes both sedimentation deconsolidation and electric field deconsolidation. Specifically, the first deconsolidation treatment includes performing sedimentation deconsolidation first, followed by electric field deconsolidation.

[0021] According to a specific embodiment of the present invention, preferably, in step (1), the sedimentation and deconsolidation includes: adding a sedimentation agent to the first heavy oil raw material for deconsolidation treatment, wherein the sedimentation agent includes a phenolic resin nonionic sedimentation agent, the amount of sedimentation agent added is 200-400 ppm of the mass of the first heavy oil raw material, the sedimentation time is 3-10 hours, and the sedimentation and deconsolidation of the heavy oil is obtained. The phenolic resin nonionic sedimentation agent can be a phenolic resin-type oil slurry sedimentation agent in the prior art, generally including alkylphenolic resins, etc. The sedimentation and deconsolidation of the present invention, through the addition of a sedimentation agent, can coagulate and flocculate metallic impurities in the first heavy oil raw material, causing the metallic impurities to settle to the lower layer of the first heavy oil raw material, thereby obtaining the sedimentation and deconsolidation of the heavy oil located in the upper layer. More preferably, the ash content of the sedimentation and deconsolidation of the heavy oil is 100-800 ppm.

[0022] According to a specific embodiment of the present invention, preferably, in step (1), the electric field deconsolidation includes: passing the first heavy oil raw material or the sedimentation-deconsolidated heavy oil through a filter containing filler under the action of an electric field, wherein the strength of the electric field is 4-7 kV / m, and the flow rate of the first heavy oil raw material or the sedimentation-deconsolidated heavy oil through the filter containing filler is 0.1-0.3 m / s, thereby obtaining the electric field-deconsolidated heavy oil. In this process, the molecular clusters containing metal impurities in the first heavy oil raw material are attracted to the surface of the filler by dielectric force, thereby removing the metal impurities from the first heavy oil raw material. The filler includes one or more of barium titanate, lead titanate, lead zirconate titanate, and lead magnesium niobate. The filler can be a sphere with a diameter of 200-1000 μm. The filter containing filler can be a device in the prior art, such as a hollow filter containing filler. Furthermore, the electric field can be a non-uniform electric field, with intermittent energization and backwashing. More preferably, the ash content of the heavy oil after electric field desolidification is 40-80 ppm.

[0023] According to a specific embodiment of the present invention, preferably, in step (1), the ash content of the first purified heavy oil is 40 to 80 ppm.

[0024] In this invention, ash content refers to all metallic impurities, generally including one or more of Fe, Ni, V, Al, Cu, Na and Ca.

[0025] According to a specific embodiment of the present invention, preferably, in step (1), based on the total mass of the second heavy oil feedstock as 100%, the content of saturated fraction is 0.2-28%, the content of aromatic fraction is 40-75%, the content of gum is 4-30%, the content of asphaltenes is 3-30%, the content of sulfur is 0.05-0.6%, the content of nitrogen is 0.01-0.4%, and the content of residual carbon is 13-20%; the density of the second heavy oil feedstock at 20°C is 1.05-1.18 g / cm³. 3 The dynamic viscosity at 130℃ is 0.5–0.8 Pa·s; and the ash content of the second heavy oil feedstock is 300–2000 ppm. Specifically, the second heavy oil feedstock includes, but is not limited to, one or more of ethylene tar, vacuum residue, thermal cracking residue, and deoiled bitumen from vacuum residue.

[0026] According to a specific embodiment of the present invention, preferably, in step (1), the second deconsolidation treatment includes centrifugal deconsolidation, wherein the temperature of the centrifugal deconsolidation is 130-150°C and the rotation speed is 3000-4000 rpm. Specifically, the centrifugal deconsolidation is carried out using a centrifuge, which may include at least one of a horizontal screw centrifuge, a disc centrifuge, and a horizontal screw sedimentation centrifuge. The second heavy oil raw material is heated to 130-150°C and then enters the centrifuge for centrifugal deconsolidation, and the rotation speed of the centrifuge is controlled at 3000-4000 rpm.

[0027] According to a specific embodiment of the present invention, preferably, in step (1), the ash content of the second purified heavy oil is 10 to 100 ppm.

[0028] According to a specific embodiment of the present invention, preferably, step (2) includes: mixing the second purified heavy oil with nanoporous carbon under the action of intermittently set ultrasound, wherein the power of the ultrasound is 350-400W / L, and the intermittent setting includes: generating ultrasound for 20-30 seconds, then stopping for 20-30 seconds, then generating ultrasound for 20-30 seconds, then stopping for 20-30 seconds, and so on, to obtain the third purified heavy oil in the upper layer and the heavy oil containing nanoporous carbon in the lower layer. The mixing time can be adjusted according to the mass of the second purified heavy oil being processed, and the present invention does not impose any special restrictions on it. Specifically, the mixing of the second purified heavy oil and nanoporous carbon can be carried out in a mixing tank equipped with an ultrasound generator. The mixing tank equipped with the ultrasound generator can adopt the device in the prior art, and the present invention does not impose any special restrictions on its structure.

[0029] According to a specific embodiment of the present invention, preferably, in step (2), the specific surface area of ​​the nanoporous carbon is 200–1800 m². 2 / g, with a pore size of 0.1-10nm and a D50 particle size of 10-100nm, wherein the mass content of the nanoporous carbon in the second purified heavy oil is 200-500ppm. More preferably, the nanoporous carbon includes one or more of porous graphene, porous carbon nanotubes, and nanoporous activated carbon.

[0030] This invention mixes nanoporous carbon with second purified heavy oil. Due to the small particle size and large specific surface area of ​​nanoporous carbon, it exhibits good dispersion performance in the second purified heavy oil. Simultaneously, the invention utilizes ultrasonic assistance to ensure sufficient contact between the nanoporous carbon and the second purified heavy oil, adsorbing large aromatic hydrocarbon clusters containing metallic impurities in the second purified heavy oil. This reduces the content of large aromatic hydrocarbon clusters in the third purified heavy oil, minimizing the rapid condensation and formation of pyrolysis reaction centers during subsequent deheating, thereby inhibiting the formation of smaller mesophase structures in petroleum coke. Furthermore, by controlling the performance parameters and dosage of nanoporous carbon within the aforementioned range, this invention can better regulate the structure of petroleum coke.

[0031] According to a specific embodiment of the present invention, preferably, in step (3), the solid-liquid separation of the heavy oil containing nanoporous carbon includes centrifugal separation, wherein the centrifugal separation speed is 1000-1500 r / min and the temperature is 50-70℃. Specifically, the solid-liquid separation is carried out using a continuous bag-feeding centrifuge, in which non-graphite carbon material precursors can be collected, and the fourth purified heavy oil is obtained by centrifugal separation. The non-graphite carbon material precursors include asphaltenes and nanoporous carbon. Furthermore, the fourth purified heavy oil does not contain nanoporous carbon.

[0032] According to a specific embodiment of the present invention, preferably, in step (4), the mixing mass ratio of the third purified heavy oil and the fourth purified heavy oil is (6-9):(4-0.5), and the mixing mass ratio of the total amount of the first purified heavy oil, the third purified heavy oil, and the fourth purified heavy oil is (1-5):10. More preferably, all the third purified heavy oil obtained in step (2) and all the fourth purified heavy oil obtained in step (3) are first mixed to obtain the fifth purified heavy oil; then the first purified heavy oil and the fifth purified heavy oil are mixed at a mass ratio of (1-5):10.

[0033] According to a specific embodiment of the present invention, preferably, in step (4), the mixing is carried out online, and the online mixing temperature is 100-150°C and the linear velocity is 0.3-0.5 m / s.

[0034] According to a specific embodiment of the present invention, preferably, step (5) includes: heating the heavy mixed oil to obtain heated heavy mixed oil; then subjecting the heated heavy mixed oil to vacuum distillation to obtain coking mixed oil; wherein the temperature of the heated heavy mixed oil is 350-370°C; the vacuum distillation is carried out using a fractionating column, controlling the pressure inside the fractionating column to 20-50 kPa, the upper temperature of the fractionating column to 120-150°C and the lower temperature to 360-380°C, and the coking mixed oil is obtained at the bottom of the fractionating column. The heating of the heavy mixed oil can be performed using conventional heating devices in the art, such as tubular furnaces. The present invention does not impose special limitations on the heating time of the heavy mixed oil, which can be conventionally adjusted by those skilled in the art.

[0035] According to a specific embodiment of the present invention, preferably, in step (5), the coking blend oil has a distillation range of 350–680°C and a density of 1.0–1.1 g / cm³ at 20°C. 3 Based on the total mass of the coking blend oil as 100%, the saturated content is 2-22%, the aromatic content is 50-80%, the gum content is 5-22%, the asphaltenes content is 5-22%, the sulfur content is 0.1-0.6%, the nitrogen content is 0.01-0.4%, and the residual carbon content is 5-15%.

[0036] According to a specific embodiment of the present invention, preferably, in step (5), the fractionation tower obtains gasoline, diesel, light wax oil fractions and heavy wax oil fractions through a measuring line; wherein, the density of the gasoline at 20°C is 0.76~0.78g / cm³. 3 The diesel fuel has a density of 0.80–0.85 g / cm³ at 20°C. 3 The light wax oil fraction has a density of 0.86–0.87 g / cm³ at 20°C. 3 The density of the heavy wax oil fraction at 20°C is 0.88–0.89 g / cm³. 3 .

[0037] This invention controls the conditions of the fractionation tower within the aforementioned range and designs the distillation range, thereby obtaining a coking blended oil with adjusted composition at the bottom of the fractionation tower. At the same time, gasoline, diesel, light wax oil fractions and heavy wax oil fractions byproducts can be obtained through measuring lines, which can be used as fuel oil, thus maximizing the utilization of heavy oil feedstock.

[0038] According to a specific embodiment of the present invention, preferably, step (6) includes: heating the coking mixture oil and injecting steam during the heating process to obtain heated coking mixture oil; then pyrolyzing the heated coking mixture oil to obtain petroleum coke precursor and high-temperature oil gas; wherein the ratio of the steam flow rate to the mass of the coking mixture oil is: 1-5 L / min steam: 100 kg coking mixture oil; the temperature of the heated coking mixture oil is 480-510°C; the pyrolysis temperature is 420-470°C, the time is 24-48 hours, and the pressure is 0.1-0.7 MPa. The present invention, by controlling the heating and pyrolysis conditions within the above ranges, facilitates the formation of petroleum coke with better uniformity.

[0039] In this invention, the coking oil mixture can be heated using conventional heating devices in the art, such as tubular furnaces. Furthermore, the heating can be constant-temperature heating or variable-temperature heating. Constant-temperature heating involves selecting any temperature point within the range of 480–510°C and maintaining a constant temperature throughout the entire heating process. Variable-temperature heating involves gradually increasing the temperature from one temperature point within the range of 480–510°C to another at a heating rate of 0.5–1°C / h; alternatively, variable-temperature heating can involve maintaining a constant temperature at any temperature point within the range of 480–510°C for a period of time, then increasing the temperature to another temperature point within the range of 480–510°C and maintaining that temperature for a period of time. This invention does not impose special limitations on the heating time of the coking oil mixture, and such adjustments can be made conventionally by those skilled in the art.

[0040] Furthermore, the pyrolysis of the heated coking mixture can be performed using a conventional pyrolysis reactor, and the present invention does not impose any special limitations on its structure. The pyrolysis can be constant-pressure pyrolysis or pressure-swing pyrolysis. Constant-pressure pyrolysis involves selecting any pressure point within the range of 0.1–0.7 MPa and maintaining a constant pressure throughout the entire pyrolysis process. Pressure-swing pyrolysis can involve gradually increasing or decreasing the pressure from any pressure point within the range of 0.1–0.7 MPa to another pressure point at a rate of 0.01–0.02 MPa per hour; alternatively, pressure-swing pyrolysis can involve maintaining a constant pressure at any pressure point within the range of 0.1–0.7 MPa for a period of time, then increasing or decreasing the pressure to another pressure point within the range of 0.1–0.7 MPa and maintaining this pressure at a constant pressure for a period of time.

[0041] According to a specific embodiment of the present invention, preferably, step (6) further includes: distilling the high-temperature oil gas together with the heavy mixed oil in step (5); the temperature of the high-temperature oil gas is 370-410°C. Specifically, after the high-temperature oil gas is discharged from the top of the pyrolysis reactor, it enters the fractionation tower in step (5), where it undergoes heat and mass transfer with the heavy mixed oil, and is distilled together with the heavy mixed oil to obtain coking mixed oil, as well as gasoline, diesel, light wax oil fractions and heavy wax oil fractions.

[0042] According to a specific embodiment of the present invention, preferably, in step (7), the modification treatment includes: heating the light wax oil fraction obtained in step (5) to 480-510°C, and then introducing it into the petroleum coke precursor for modification treatment for 3-6 hours. By performing this modification treatment, the present invention achieves better uniformity of the petroleum coke in the upper and lower parts of the pyrolysis reactor. After the modification treatment, the obtained petroleum coke can be cooled to 100-150°C by low-temperature steam and / or water, and then cut out of the pyrolysis reactor by high-pressure water, thereby obtaining blocky petroleum coke.

[0043] According to a specific embodiment of the present invention, preferably, in step (8), the carbonization temperature is 1000–1400°C and the time is 3–6 hours. Furthermore, the carbonization is carried out in a protective gas atmosphere, such as nitrogen and / or argon. The carbonization can be carried out in conventional equipment, such as a carbonization furnace. After the carbonization is completed, a protective gas can be introduced for cooling, and after cooling to room temperature, the non-graphite carbon material is obtained. The non-graphite carbon material precursor of the present invention includes asphaltene and nanoporous carbon, wherein smaller asphaltene particles enter the pores of the nanoporous carbon, and larger asphaltene particles coat the surface of the nanoporous carbon. Therefore, the inventors speculate that the non-graphite carbon material formed after carbonization includes: a carbon skeleton, carbon microcrystals distributed in the pores of the carbon skeleton, and carbon microcrystals coating the surface of the carbon skeleton.

[0044] According to a specific embodiment of the present invention, preferably, step (9) includes:

[0045] (9)-1. The petroleum coke is subjected to at least pulverization, liquid phase coating, heat treatment and graphitization to obtain artificial graphite material;

[0046] (9)-2. Mix the artificial graphite material and the non-graphite carbon material to obtain the negative electrode material.

[0047] According to a specific embodiment of the present invention, preferably, in step (9)-1, the D10 particle size of the pulverized petroleum coke is 2-3 μm, the D50 particle size is 14-16 μm, and the D90 particle size is 21-23 μm. Specifically, the pulverization may include sequential coarse crushing and fine crushing; coarse crushing may be carried out using a jaw crusher or similar device to crush the petroleum coke into particles of 1-3 mm; fine crushing may be carried out using an air jet mill and / or a mechanical grinder, etc., and these devices should have pulverization and grading functions to obtain petroleum coke with the particle size range described above in the present invention. In addition, drying may be carried out before pulverization, and indirect drying may be carried out using steam at a temperature of 150-200°C for 2-4 hours.

[0048] According to a specific embodiment of the present invention, preferably, in step (9)-1, the liquid phase coating includes: using the heavy wax oil fraction (obtained in step (5)) as a coating agent, heating the coating agent to 50-100°C, then pressurizing it to 2-3 MPa, and then spraying the coating agent onto the pulverized petroleum coke being stirred through a spray head with a diameter of 0.5-1 mm, a stirring speed of 500-1000 r / min, and the amount of coating agent used being 1-10% of the mass of the pulverized petroleum coke, thereby obtaining petroleum coke with a coating layer. Specifically, the coating can be carried out using a liquid phase coating machine, and the residence time of the pulverized petroleum coke in the liquid phase coating machine can be 20-40 min. By using the coating method of the present invention, the coating agent is sprayed out at high speed and contacts the stirred petroleum coke, thereby making the formed coating layer more uniform. After coating is completed, nitrogen gas can be introduced into the liquid phase coating machine for cooling. After cooling to room temperature, petroleum coke with a coating layer is obtained.

[0049] This invention uses heavy wax oil fraction to coat petroleum coke, which fills the pores and defects on the surface of the petroleum coke, helping to improve the heat and mass transfer efficiency in subsequent heat treatment and graphitization processes, and promoting the growth and development of graphite crystals. Furthermore, the carbonaceous structure formed by the coating layer of this invention under subsequent high-temperature conditions can prevent oxygen from contacting the interior of the petroleum coke, thereby improving the oxidation resistance of the artificial graphite material. Simultaneously, the coating layer of this invention can form a conductive network on the graphite surface during subsequent heat treatment and graphitization processes, improving the conductivity of the artificial graphite material. By using the aforementioned heavy wax oil fraction and controlling the liquid-phase coating conditions within the above-mentioned range, this invention can adjust the size, orientation, and defect density of graphite crystals in subsequent processes, thereby enabling the artificial graphite material of this invention to possess high electrochemical performance.

[0050] According to a specific embodiment of the present invention, preferably, in step (9)-1, the heat treatment temperature is 700–900°C and the time is 4–6 hours. Furthermore, the heat treatment is performed in a protective gas atmosphere, such as nitrogen and / or argon. The heat treatment can be performed in conventional equipment, such as a carbonization furnace.

[0051] According to a specific embodiment of the present invention, preferably, in step (9)-1, the graphitization temperature is 2950–3100°C and the time is 4–12 hours. Furthermore, the graphitization is carried out in a protective gas atmosphere, such as nitrogen and / or argon. The graphitization can be carried out in conventional equipment in the art, such as a graphitization furnace.

[0052] According to a specific embodiment of the present invention, preferably, in step (9)-1, the D10 particle size of the artificial graphite material is 2-3 μm, the D50 particle size is 14-16 μm, and the D90 particle size is 21-23 μm.

[0053] According to a specific embodiment of the present invention, preferably, in step (9)-2, the D10 particle size of the non-graphite carbon material is 1-2 μm, the D50 particle size is 7-9 μm, and the D90 particle size is 16-18 μm. Specifically, the non-graphite carbon material obtained above can be first subjected to pulverization treatment, for example, using an air jet mill and / or a mechanical grinder, to obtain the above particle size range, and then mixed with the graphite material.

[0054] According to a specific embodiment of the present invention, preferably, in step (9)-2, the mass ratio of the artificial graphite material to the non-graphite carbon material is 10:(0.1~1).

[0055] According to a specific embodiment of the present invention, preferably, in step (9)-2, the mixing of the artificial graphite material and the non-graphite carbon material is carried out under stirring conditions, with a stirring speed of 1000-1500 r / min and a mixing time of 20-60 min. The mixing is carried out in a conventional device in the art, such as a mixer with a high-speed stirring function.

[0056] A second aspect of the present invention provides a petroleum coke, which is prepared by the above-described method of preparing petroleum coke, non-graphite carbon material and negative electrode material.

[0057] According to a specific embodiment of the present invention, preferably, the petroleum coke contains 1-5% fine mosaic structure, 5-10% small flake structure, 40-60% large flake structure, 3-8% short fiber structure, 25-40% fine fiber structure, and 2-12% coarse fiber structure. It should be noted that the content of these microstructures is based on the total number of microstructures in the petroleum coke being 100%, where the total number of microstructures includes the total number of fine mosaic structure, small flake structure, large flake structure, short fiber structure, fine fiber structure, and coarse fiber structure.

[0058] According to a specific embodiment of the present invention, preferably, the true density of the petroleum coke is 1.4–1.6 g / cm³. 3 Furthermore, based on the total mass of the petroleum coke as 100%, the volatile matter content is 8-12%, the ash content is 0.01-0.02%, the sulfur content is 0.5-1%, and the nitrogen content is 0.1-0.3%.

[0059] The petroleum coke of this invention has a low content of fine mosaic structure, small flake structure, and short fiber structure, and a high content of large flake structure and fine fiber structure. The inventors have discovered that if the content of fine mosaic structure, small flake structure, and short fiber structure in the petroleum coke is too high, it is difficult to form a highly ordered artificial graphite material after subsequent graphitization. Furthermore, the connection relationship between graphite microcrystals becomes too complex, hindering the lithium-ion insertion and extraction process. Even when pulverized to micron-level particles later, the uniformity between particles is poor, leading to differences in electrochemical reactions at different locations, affecting the charge-discharge performance and cycle stability of the battery. The petroleum coke of this invention, with its high content of large-sheet and fine-fiber structures, is more likely to form a more regular layered graphite structure after subsequent graphitization. The larger graphite microcrystal layers provide greater ion storage space, increasing the number of lithium-ion storage sites and improving battery capacity. Simultaneously, the high content of large-sheet and fine-fiber structures in the petroleum coke of this invention, after subsequent graphitization, gives the artificial graphite material a suitable porosity, allowing it to accommodate more electrolyte, increasing the lithium-ion diffusion rate, and mitigating the volume changes caused by lithium-ion insertion and extraction. This improves both battery capacity and cycle stability. Furthermore, the petroleum coke of this invention has a lower impurity content. All of these factors contribute to the high electrochemical performance of the artificial graphite material prepared from the petroleum coke of this invention.

[0060] A third aspect of the present invention provides a non-graphite carbon material, which is prepared by the above-described methods for preparing petroleum coke, non-graphite carbon material and negative electrode material.

[0061] As described above, the inventors hypothesize that the non-graphite carbon material formed after carbonization comprises: a carbon framework, carbon microcrystals distributed within the pores of the carbon framework, and carbon microcrystals coating the surface of the carbon framework. The non-graphite carbon material of this invention can provide multi-angle and multi-channel pathways for lithium ion insertion and detachment, exhibiting high electrochemical performance.

[0062] According to a specific embodiment of the present invention, preferably, the interlayer spacing of the non-graphite carbon material is 0.354 nm to 0.358 nm.

[0063] The fourth aspect of the present invention provides a negative electrode material, which is prepared by the above-described preparation method of petroleum coke, non-graphite carbon material and negative electrode material.

[0064] The present invention has at least the following beneficial effects:

[0065] This invention uses heavy petroleum oil as a carbon source, improving the utilization rate and product diversity of heavy petroleum oil. It fully utilizes heavy petroleum oil, a byproduct of refining, and adjusts the composition of the heavy petroleum oil by introducing nanoporous carbon as a structure modifier. This adjusts the ordered structure of the petroleum coke, resulting in a superior microstructure. Simultaneously, this invention also co-produces non-graphite carbon materials. Therefore, this invention can simultaneously prepare high-quality petroleum coke and non-graphite carbon materials. Furthermore, this invention uses this petroleum coke to prepare artificial graphite materials through liquid-phase coating, using a byproduct from the overall process as the coating agent. This maximizes raw material utilization while promoting the performance of the artificial graphite materials. The negative electrode material prepared using the artificial graphite material of this invention combined with the non-graphite carbon material of this invention exhibits high electrochemical performance, showing a significant performance improvement compared to artificial graphite materials prepared from conventional petroleum coke. The negative electrode material of this invention is suitable for various high-energy-density energy storage batteries, especially lithium-ion batteries. Lithium-ion batteries prepared using the negative electrode material of this invention exhibit high capacity, efficiency, and cycle performance. This invention also has the advantages of simple process and low cost, making it suitable for large-scale industrial application. Attached Figure Description

[0066] Figure 1 is a schematic diagram of the preparation system of petroleum coke, non-graphite carbon material and negative electrode material in Examples 1 to 3 of the present invention.

[0067] Explanation of icon numbers:

[0068] 1-First heavy oil feedstock storage tank; 2-Second heavy oil feedstock storage tank; 3-Sedimentation tank; 4-Electric field deconsolidator; 5-First centrifuge; 6-Blending tank; 7-Nanoporous carbon storage tank; 8-Online mixer; 9-Second centrifuge; 10-First tubular heater; 11-Fracturing tower; 12-Second tubular heater; 13-Pyrolysis reactor; 14-Dryer; 15-Coarse crusher; 16-Fine crusher; 17-Liquid phase coating machine; 18-First carbonization furnace; 19-Graphitization furnace; 20-Second carbonization furnace; 21-Pulverizer; 22-Mixer; 601-Ultrasonic generator; 602-Data acquisition unit. Detailed Implementation

[0069] To provide a clearer understanding of the technical features, objectives, and beneficial effects of the present invention, the present invention will now be described in detail below, but this should not be construed as limiting the scope of the invention.

[0070] Test method:

[0071] The saturated content, aromatic content, resin content and asphaltene content of the oil were obtained according to the test results in SH / T 0509-2010 "Determination of Four Components of Petroleum Asphalt".

[0072] The sulfur content of the oil was determined according to the specifications in GB / T 17040-2019 "Determination of Sulfur Content in Petroleum and Petroleum Products by Energy Dispersive X-ray Fluorescence Spectrometry".

[0073] Nitrogen content of oil: Tested according to the description in SH / T 0657-2007 "Determination of trace nitrogen in liquid petroleum hydrocarbons by oxidative combustion and chemiluminescence method".

[0074] The carbon residue content of the oil was determined according to the specifications in GB / T17144-2021 "Determination of Carbon Residue in Petroleum Products (Trace Method)".

[0075] Ash content of oil: Tested according to the method for determination of ash content in petroleum products in GB / T 508-1985.

[0076] Oil density: Tested according to the specifications in GB / T 1884-2000 "Laboratory Determination of Density of Crude Oil and Liquid Petroleum Products (Density Meter Method)".

[0077] The dynamic viscosity of the oil was determined according to the specifications in GB / T 265-1988, "Determination of kinematic viscosity and calculation of dynamic viscosity of petroleum products".

[0078] The true density of petroleum coke was determined according to the method described in SH / T 0033-1990 "Determination of True Density of Petroleum Coke".

[0079] The volatile matter content, ash content, and sulfur content of petroleum coke were obtained by testing in accordance with the records in SH / T 0313-1992 "Petroleum Coke Inspection Method".

[0080] Nitrogen content of petroleum coke: Tested according to the records in SN / T 2422-2010 "Determination of Nitrogen in Imported and Exported Petroleum Coke by Thermal Conductivity Method".

[0081] The content of different microstructures of petroleum coke was obtained by testing according to the records in Appendix A of YB / T 4822-2020 "Analysis Standard of Mesophase Coke in Coal-Series Needle Coke".

[0082] The interlayer spacing of non-graphite carbon materials was measured according to the records in Appendix E of GB / T 24533-2019 "Graphite Anode Materials for Lithium-ion Batteries".

[0083] Electrochemical performance testing: The negative electrode material was mixed uniformly with carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), and conductive agent Super-p in a mass ratio of 95:1.5:2:1.5 in an appropriate amount of deionized water to obtain a negative electrode slurry. The negative electrode slurry was coated onto copper foil and then dried in a vacuum drying oven for 12 hours to obtain the negative electrode. The electrolyte was a 1 mol / L LiPF6 electrolyte, in which the solvent was a mixed solvent of ethylene carbonate (EC), diethyl carbonate (DEC), and dimethyl carbonate (DMC) in a volume ratio of 1:1:1. The separator was a PP-PE-PP composite membrane. The counter electrode was a lithium sheet. Using the above-mentioned negative electrode, electrolyte, separator, and counter electrode, a lithium-ion button half-cell was assembled in a glove box. The cell size was Φ20.0×1.6mm. A constant current charge-discharge experiment was conducted in the Xinwei Battery Testing System. The charge-discharge voltage was 0.005~2V, and the charge-discharge current was 0.1C.

[0084] It should be noted that in the following examples and comparative examples, if the sum of the contents of the four components is not equal to 100%, it is due to testing errors, which is a common occurrence in the art.

[0085] Example 1

[0086] This embodiment provides a petroleum coke, a non-graphite carbon material, and a negative electrode material, and their preparation methods include the following steps:

[0087] Catalytic cracking slurry was used as the first heavy oil feedstock. Based on the total mass of the first heavy oil feedstock (100%), the content of saturated fraction was 14%, aromatic fraction was 68%, resin content was 13%, asphaltenes content was 5%, sulfur content was 0.7%, nitrogen content was 0.2%, and residual carbon content was 15%; the density at 20℃ was 0.98 g / cm³. 3The dynamic viscosity at 130℃ is 0.33 Pa·s; and the ash content of the first heavy oil feedstock is 3200 ppm. The first heavy oil feedstock is fed into a settling tank, and a settling agent is added for settling and desolidification. The settling agent is a commercially available phenolic resin nonionic settling agent, and the amount of settling agent added is 200 ppm of the mass of the first heavy oil feedstock. The settling time is 10 hours, and the settled and desolidified heavy oil is obtained. The ash content of the settled and desolidified heavy oil is 800 ppm.

[0088] Then, the sedimented and deconsolidated heavy oil is introduced into an electric field deconsolidator. Under the action of an electric field, it passes through a hollow filter containing packing material. The electric field strength is 4 kV / m, and the flow rate of the sedimented and deconsolidated heavy oil through the filter containing packing material is 0.2 m / s, resulting in electric field deconsolidated heavy oil. The packing material consists of barium titanate microspheres with a diameter of 200 μm, and the electric field can be a non-uniform electric field, with intermittent energizing and backwashing. The ash content of the electric field deconsolidated heavy oil is 70 ppm, which is the first purified heavy oil.

[0089] Vacuum residue was used as the second heavy oil feedstock. Based on the total mass of the second heavy oil feedstock (100%), the content of saturated fraction was 22%, aromatic fraction was 48%, resin content was 24%, asphaltenes content was 6%, sulfur content was 0.4%, nitrogen content was 0.2%, and residual carbon content was 13%; the density at 20℃ was 1.07 g / cm³. 3 The dynamic viscosity at 130℃ is 0.7 Pa·s; and the ash content of the second heavy oil feedstock is 2000 ppm. The second heavy oil feedstock is heated to 135℃ and then centrifuged to remove consolidation. A horizontal screw centrifuge is used, and the centrifuge speed is controlled at 3000 r / min to obtain the second purified heavy oil. The ash content of the second purified heavy oil is 30 ppm. The second purified heavy oil is then placed in a mixing tank equipped with an ultrasonic generator, and nanoporous activated carbon with a specific surface area of ​​1800 m² is added. 2 / g, with a pore size of 0.5-4nm, a D50 particle size of 90nm, and a mass content of 200ppm of nanoporous activated carbon in the second purified heavy oil, the second purified heavy oil and nanoporous activated carbon are mixed under the action of intermittently set ultrasonic waves with a power of 350W / L. The intermittent setting method is: the ultrasonic waves are generated for 30 seconds, then stopped for 30 seconds, then generated for 30 seconds, then stopped for 30 seconds, and so on. The ultrasonic waves are generated and stopped intermittently in this manner to obtain the third purified heavy oil in the upper layer of the mixing tank and the heavy oil containing nanoporous carbon in the lower layer of the mixing tank.

[0090] Heavy oil containing nanoporous carbon is fed into a centrifuge for centrifugal separation. Specifically, a continuous bag-feeding centrifuge is used. The centrifuge speed is 1100 r / min and the temperature is 50℃. Non-graphite carbon material precursors can be collected in the bag and then centrifuged to obtain the fourth purified heavy oil.

[0091] All of the third-purified heavy oil and all of the fourth-purified heavy oil (mass ratio of 8.5:1) were mixed to obtain the fifth-purified heavy oil; then the first-purified heavy oil and the fifth-purified heavy oil were mixed online using an online mixer at a mass ratio of 1:10, a temperature of 100℃ and a linear velocity of 0.3 m / s to obtain a mixed heavy oil.

[0092] The heavy mixed oil is heated to 370℃ in a tubular heater (i.e., the outlet temperature of the tubular heater is 370℃) to obtain the heated heavy mixed oil. The heated heavy mixed oil is then fed into a fractionating tower through the middle section for vacuum distillation. The pressure inside the fractionating tower is controlled at 20 kPa, the upper temperature is 130℃, and the lower temperature is 370℃. Coking mixed oil is obtained from the bottom of the fractionating tower, and gasoline, diesel, light wax oil, and heavy wax oil fractions are obtained from the side streams of the fractionating tower. The coking mixed oil has a distillation range of 380–610℃ and a density (20℃) of 1.03 g / cm³. 3 Based on the total mass of the coking blend oil as 100%, the saturated content is 20%, the aromatic content is 53%, the gum content is 20%, the asphaltenes content is 7%, the sulfur content is 0.5%, the nitrogen content is 0.3%, and the carbon residue content is 12%; the density of the gasoline (20℃) is 0.762 g / cm³. 3 The density of diesel oil (at 20℃) is 0.83 g / cm³. 3 The density (20℃) of the light wax oil fraction is 0.863 g / cm³. 3 The density (20℃) of the heavy wax oil fraction is 0.885 g / cm³. 3 ;

[0093] The coking mixture is heated in a tubular heater while steam is injected at a ratio of 1 L / min to 100 kg of coking mixture. The heating temperature is 485°C for the first 18 hours and 500°C for the next 6 hours, with a heating time of 24 hours. The heated coking mixture is then introduced into the pyrolysis reactor from the bottom, where the temperature is controlled at 420°C and the pyrolysis pressure is 0.2 MPa for the first 18 hours and 0.1 MPa for the next 6 hours, with a pyrolysis time of 24 hours. This yields petroleum coke precursors and high-temperature oil gas. The high-temperature oil gas, at 380°C, is discharged from the top of the pyrolysis reactor and then enters the fractionation tower mentioned above for distillation together with the heated heavy mixture.

[0094] The light wax oil fraction obtained from the side stream of the above-mentioned fractionation tower is heated to 500°C and then passed into a pyrolysis reactor to modify the petroleum coke precursor. The treatment time is 4 hours to obtain petroleum coke. The obtained petroleum coke is then cooled to 100°C by low-temperature steam and then cut out from the pyrolysis reactor by high-pressure water to obtain blocky petroleum coke.

[0095] Tests revealed that the petroleum coke contained 2% fine mosaic structure, 9% small flake structure, 42% large flake structure, 8% short fiber structure, 28% fine fiber structure, and 11% coarse fiber structure. The true density of the petroleum coke sampled from the top of the pyrolysis reactor was 1.51 g / cm³. 3 The true density of petroleum coke sampled from the bottom of the pyrolysis reactor was 1.51 g / cm³. 3 The volatile matter content of petroleum coke sampled from the upper part of the pyrolysis reactor was 9.3%, and the volatile matter content of petroleum coke sampled from the lower part of the pyrolysis reactor was 9%. Therefore, the petroleum coke has good homogeneity. The samples from the upper and lower parts of the pyrolysis reactor were mixed and tested. The results showed that, based on the total mass of petroleum coke (100%), the ash content was 0.012%, the sulfur content was 0.7%, and the nitrogen content was 0.16%.

[0096] The non-graphite carbon material precursor obtained by centrifugation was fed into a carbonization furnace and carbonized at 1200°C for 6 hours in a nitrogen atmosphere. Nitrogen was then introduced into the carbonization furnace for cooling. After cooling to room temperature, the non-graphite carbon material was obtained. The non-graphite carbon material was then pulverized using an air jet mill to obtain pulverized non-graphite carbon material with a D10 particle size of 1.5 μm, a D50 particle size of 7.5 μm, and a D90 particle size of 16.8 μm. The interlamellar spacing of the non-graphite carbon material was approximately 0.355 nm.

[0097] The petroleum coke is fed into a dryer and indirectly dried using steam at 180°C for 2 hours. Then, it is crushed into 1-3 mm particles by a coarse crusher (specifically a jaw crusher), and then further crushed and classified by a fine crusher (specifically an air jet mill) to obtain pulverized petroleum coke with a D10 particle size of 2.5 μm, a D50 particle size of 14.7 μm, and a D90 particle size of 21.6 μm.

[0098] The pulverized petroleum coke is fed into a liquid phase coating machine. The heavy wax oil fraction obtained from the side stream of the fractionation tower is used as the coating agent. The coating agent is heated to 50°C and then pressurized to 2.5 MPa. The coating agent is then sprayed onto the pulverized petroleum coke being stirred through a nozzle with a diameter of 1 mm. The stirring speed is 1000 r / min. The amount of coating agent used is 3% of the mass of the pulverized petroleum coke. The residence time of the pulverized petroleum coke in the liquid phase coating machine is 30 min. Nitrogen gas is then introduced into the liquid phase coating machine for cooling. After cooling to room temperature, petroleum coke with a coating layer is obtained.

[0099] The coated petroleum coke was fed into a carbonization furnace and heat-treated in a nitrogen atmosphere at a temperature of 900°C for 4 hours. Then, it was graphitized in a graphitization furnace in a nitrogen atmosphere at a temperature of 3000°C for 4 hours to obtain artificial graphite material with a D10 particle size of 2.5 μm, a D50 particle size of 14.7 μm, and a D90 particle size of 21.6 μm, consistent with the pulverized petroleum coke described above.

[0100] The artificial graphite material and the pulverized non-graphite material were added to a mixer at a mass ratio of 10:0.1 and mixed under stirring conditions. The stirring speed was 1000 r / min and the mixing time was 30 min to obtain the negative electrode material.

[0101] Lithium-ion button half-cells were prepared using the negative electrode material as described above.

[0102] Tests showed that the initial delithiation capacity (i.e., initial reversible specific capacity) of the lithium-ion button half-cell prepared using the negative electrode material of this embodiment was 410 mAh / g, and the initial coulombic efficiency was 95%.

[0103] Example 2

[0104] This embodiment provides a petroleum coke, a non-graphite carbon material, and a negative electrode material, and their preparation methods include the following steps:

[0105] Furfural extract oil was used as the first heavy oil feedstock. Based on the total mass of the first heavy oil feedstock (100%), the saturated content was 13%, the aromatic content was 72%, the resin content was 14%, the asphaltenes content was 1%, the sulfur content was 0.4%, the nitrogen content was 0.2%, and the residual carbon content was 13%; the density at 20℃ was 0.98 g / cm³. 3 The dynamic viscosity at 130℃ is 0.32 Pas·; and the ash content of the first heavy oil feedstock is 500 ppm. The first heavy oil feedstock is introduced into an electric field deconsolidator, and under the action of an electric field, it passes through a hollow filter containing packing material. The electric field strength is 6 kV / m, and the flow rate of the first heavy oil feedstock through the filter containing packing material is 0.2 m / s, resulting in heavy oil after electric field deconsolidation. The packing material consists of barium titanate microspheres with a diameter of 1000 μm, and the electric field can be a non-uniform electric field, with intermittent energization and backwashing. The ash content of the heavy oil after electric field deconsolidation is 70 ppm, which is the first purified heavy oil.

[0106] Ethylene tar was used as the feedstock for the second heavy oil. Based on the total mass of the second heavy oil feedstock (100%), the saturated content was 0.3%, the aromatic content was 70%, the resin content was 4.5%, the asphaltenes content was 25.2%, the sulfur content was 0.05%, the nitrogen content was 0.01%, and the residual carbon content was 17%; the density at 20℃ was 1.08 g / cm³. 3 The dynamic viscosity of the second heavy oil feedstock at 130℃ is 0.7 Pa·s; and the ash content of the second heavy oil feedstock is 300 ppm. The second heavy oil feedstock is heated to 135℃ and then centrifuged to remove consolidation. A horizontal screw centrifuge is used, and the centrifuge speed is controlled at 4000 r / min to obtain the second purified heavy oil. The ash content of the second purified heavy oil is 10 ppm. The second purified heavy oil is then placed in a mixing tank equipped with an ultrasonic generator, and porous graphene with a specific surface area of ​​600 m² is added. 2 / g, with a pore size of 0.5-2nm, a D50 particle size of 15nm, and a porous graphene content of 300ppm in the second purified heavy oil, the second purified heavy oil and porous graphene were mixed under intermittent ultrasonic waves with a power of 400W / L. The intermittent setting was as follows: ultrasonic waves were generated for 30 seconds, then stopped for 30 seconds, then ultrasonic waves were generated for 30 seconds, then stopped for 30 seconds. The ultrasonic waves were generated and stopped intermittently in this manner to obtain the third purified heavy oil located in the upper layer of the mixing tank and the heavy oil containing nanoporous carbon located in the lower layer of the mixing tank.

[0107] Heavy oil containing nanoporous carbon is fed into a centrifuge for centrifugal separation. Specifically, a continuous bag-feeding centrifuge is used. The centrifuge speed is 1500 r / min and the temperature is 60℃. Non-graphite carbon material precursors can be collected in the bag and then centrifuged to obtain the fourth purified heavy oil.

[0108] All of the third-purified heavy oil and all of the fourth-purified heavy oil (mass ratio of 7:2.5) were mixed to obtain the fifth-purified heavy oil; then the first-purified heavy oil and the fifth-purified heavy oil were mixed online using an online mixer at a mass ratio of 3:10, a temperature of 100℃ and a linear velocity of 0.3 m / s to obtain a mixed heavy oil.

[0109] The heavy mixed oil is heated to 370℃ in a tubular heater (i.e., the outlet temperature of the tubular heater is 370℃) to obtain the heated heavy mixed oil. The heated heavy mixed oil is then fed into a fractionating tower through the middle section for vacuum distillation. The pressure inside the fractionating tower is controlled at 20 kPa, the upper temperature is 130℃, and the lower temperature is 370℃. Coking mixed oil is obtained from the bottom of the fractionating tower, and gasoline, diesel, light wax oil, and heavy wax oil fractions are obtained from the side streams of the fractionating tower. The coking mixed oil has a distillation range of 380–610℃ and a density (20℃) of 1.07 g / cm³. 3 Based on the total mass of the coking blend oil as 100%, the saturated content is 3%, the aromatic content is 73%, the gum content is 8%, the asphaltenes content is 16%, the sulfur content is 0.25%, the nitrogen content is 0.01%, and the carbon residue content is 15%; the density of the gasoline (20℃) is 0.771 g / cm³. 3 The density of diesel oil (at 20℃) is 0.826 g / cm³. 3 The density (20℃) of the light wax oil fraction is 0.863 g / cm³. 3 The density (20℃) of the heavy wax oil fraction is 0.882 g / cm³. 3 ;

[0110] The coking mixture is fed into a tubular heater for heating, with steam injected at a ratio of 3 L / min to 100 kg of coking mixture. The heating process involves increasing the temperature from 485°C to 509°C at a rate of 1°C / h for 24 hours, yielding the heated coking mixture. This heated coking mixture is then fed into a pyrolysis reactor from the bottom, where the temperature is controlled at 450°C. The pyrolysis process involves gradually decreasing the pressure from 0.42 MPa to 0.18 MPa at a rate of 0.01 MPa / h for 24 hours, yielding petroleum coke precursors and high-temperature oil gas. This high-temperature oil gas, at 378°C, is discharged from the top of the pyrolysis reactor and then fed into the fractionation tower mentioned above, where it is distilled together with the heated heavy mixture.

[0111] The light wax oil fraction obtained from the side stream of the above-mentioned fractionation tower is heated to 505°C and then passed into a pyrolysis reactor to modify the petroleum coke precursor. The treatment time is 3 hours to obtain petroleum coke. The obtained petroleum coke is then cooled to 100°C by low-temperature steam and then cut out from the pyrolysis reactor by high-pressure water to obtain blocky petroleum coke.

[0112] Tests revealed that the petroleum coke contained 3% fine mosaic structure, 6% small flake structure, 48% large flake structure, 4% short fiber structure, 37% fine fiber structure, and 2% coarse fiber structure. The true density of the petroleum coke sampled from the top of the pyrolysis reactor was 1.48 g / cm³. 3 The true density of petroleum coke sampled from the bottom of the pyrolysis reactor was 1.49 g / cm³. 3 The volatile matter content of petroleum coke sampled from the upper part of the pyrolysis reactor was 9.5%, and the volatile matter content of petroleum coke sampled from the lower part of the pyrolysis reactor was 9.2%. Therefore, the petroleum coke has good homogeneity. The samples from the upper and lower parts of the pyrolysis reactor were mixed and tested. The results showed that, based on the total mass of petroleum coke (100%), the ash content was 0.01%, the sulfur content was 0.7%, and the nitrogen content was 0.2%.

[0113] The non-graphite carbon material precursor obtained by centrifugation was fed into a carbonization furnace and carbonized at 1400°C for 3 hours in a nitrogen atmosphere. Nitrogen was then introduced into the carbonization furnace for cooling. After cooling to room temperature, the non-graphite carbon material was obtained. The non-graphite carbon material was then pulverized using an air jet mill to obtain pulverized non-graphite carbon material with a D10 particle size of 1.5 μm, a D50 particle size of 7.5 μm, and a D90 particle size of 16.8 μm. The interlamellar spacing of the non-graphite carbon material was approximately 0.356 nm.

[0114] The petroleum coke is fed into a dryer and indirectly dried using steam at 200°C for 4 hours. Then, it is crushed into 1-2 mm particles by a coarse crusher (specifically a jaw crusher), and then further crushed and classified by a fine crusher (specifically an air jet mill) to obtain pulverized petroleum coke with a D10 particle size of 2.3 μm, a D50 particle size of 15.6 μm, and a D90 particle size of 22.5 μm.

[0115] The pulverized petroleum coke is fed into a liquid phase coating machine. The heavy wax oil fraction obtained from the side stream of the fractionation tower is used as the coating agent. The coating agent is heated to 80°C and then pressurized to 2 MPa. The coating agent is then sprayed onto the pulverized petroleum coke being stirred through a nozzle with a diameter of 0.5 mm. The stirring speed is 900 r / min. The amount of coating agent used is 8% of the mass of the pulverized petroleum coke. The residence time of the pulverized petroleum coke in the liquid phase coating machine is 40 min. Nitrogen gas is then introduced into the liquid phase coating machine for cooling. After cooling to room temperature, petroleum coke with a coating layer is obtained.

[0116] The coated petroleum coke was fed into a carbonization furnace and heat-treated in a nitrogen atmosphere at a temperature of 800°C for 4 hours. Then it was graphitized in a graphitization furnace in a nitrogen atmosphere at a temperature of 3000°C for 5 hours, yielding an artificial graphite material with a D10 particle size of 2.3 μm, a D50 particle size of 15.6 μm, and a D90 particle size of 22.5 μm, consistent with the pulverized petroleum coke described above.

[0117] The artificial graphite material and the pulverized non-graphite material were added to a mixer at a mass ratio of 10:0.3 and mixed under stirring conditions. The stirring speed was 1500 r / min and the mixing time was 20 min to obtain the negative electrode material.

[0118] Lithium-ion button half-cells were prepared using the negative electrode material as described above.

[0119] Tests showed that the lithium-ion button half-cell prepared using the negative electrode material of this embodiment had an initial delithiation capacity of 430 mAh / g and an initial coulombic efficiency of 94%.

[0120] Example 3

[0121] This embodiment provides a petroleum coke, a non-graphite carbon material, and a negative electrode material, and their preparation methods include the following steps:

[0122] Thermally cracked residue oil was used as the first heavy oil feedstock. Based on the total mass of the first heavy oil feedstock (100%), the content of saturated fraction was 17%, aromatic fraction was 62%, resin content was 18%, asphaltenes content was 3%, sulfur content was 0.4%, nitrogen content was 0.1%, and residual carbon content was 15%; the density at 20℃ was 1.01 g / cm³. 3 The dynamic viscosity at 130℃ is 0.32 Pa·s; and the ash content of the first heavy oil feedstock is 1200 ppm. The first heavy oil feedstock is introduced into an electric field deconsolidator, and under the action of an electric field, it passes through a hollow filter containing packing material. The electric field strength is 5 kV / m, and the flow rate of the first heavy oil feedstock through the filter containing packing material is 0.1 m / s, resulting in heavy oil after electric field deconsolidation. The packing material consists of barium titanate microspheres with a diameter of 500 μm, and the electric field can be a non-uniform electric field, with intermittent energization and backwashing. The ash content of the heavy oil after electric field deconsolidation is 80 ppm, which is the first purified heavy oil.

[0123] Using the ethylene tar from Example 2 as the second heavy oil feedstock, the second heavy oil feedstock was heated to 135°C and then centrifuged in a centrifuge for deconsolidation. A horizontal screw centrifuge was used, and the centrifuge speed was controlled at 3500 r / min to obtain the second purified heavy oil. The ash content of the second purified heavy oil was 30 ppm.

[0124] The second purified heavy oil is introduced into a blending tank equipped with an ultrasonic generator, and porous carbon nanotubes with a specific surface area of ​​300 m² are added. 2 / g, with a pore size of 0.1-8nm, a D50 particle size of 90nm, and a porous carbon nanotube content of 500ppm in the second purified heavy oil, the second purified heavy oil and porous carbon nanotubes are mixed under the action of intermittently set ultrasonic waves with a power of 380W / L. The intermittent setting method is: the ultrasonic waves are generated for 20 seconds, then stopped for 20 seconds, then generated for 20 seconds, then stopped for 20 seconds, and so on. The ultrasonic waves are generated and stopped intermittently in this manner to obtain the third purified heavy oil located in the upper layer of the mixing tank and the heavy oil containing nanoporous carbon located in the lower layer of the mixing tank.

[0125] Heavy oil containing nanoporous carbon is fed into a centrifuge for centrifugal separation. Specifically, a continuous bag-feeding centrifuge is used. The centrifuge speed is 1500 r / min and the temperature is 60℃. Non-graphite carbon material precursors can be collected in the bag and then centrifuged to obtain the fourth purified heavy oil.

[0126] All of the third-purified heavy oil and all of the fourth-purified heavy oil (mass ratio of 8:1.5) were mixed to obtain the fifth-purified heavy oil; then the first-purified heavy oil and the fifth-purified heavy oil were mixed online using an online mixer at a mass ratio of 5:10, a temperature of 100℃ and a linear velocity of 0.3 m / s to obtain a mixed heavy oil.

[0127] The heavy mixed oil is heated to 370℃ in a tubular heater (i.e., the outlet temperature of the tubular heater is 370℃) to obtain the heated heavy mixed oil. The heated heavy mixed oil is then fed into a fractionating tower through the middle section for vacuum distillation. The pressure inside the fractionating tower is controlled at 20 kPa, the upper temperature is 140℃, and the lower temperature is 380℃. Coking mixed oil is obtained from the bottom of the fractionating tower, and gasoline, diesel, light wax oil, and heavy wax oil fractions are obtained from the side streams of the fractionating tower. The coking mixed oil has a distillation range of 370–660℃ and a density (20℃) of 1.10 g / cm³. 3 Based on the total mass of the coking blend oil as 100%, the saturated content is 4%, the aromatic content is 70%, the gum content is 12%, the asphaltenes content is 14%, the sulfur content is 0.24%, the nitrogen content is 0.06%, and the carbon residue content is 14%; the density of the gasoline (20℃) is 0.776 g / cm³. 3 The density of diesel oil (at 20℃) is 0.835 g / cm³. 3 The density (20℃) of the light wax oil fraction is 0.865 g / cm³. 3 The density (20℃) of the heavy wax oil fraction is 0.886 g / cm³. 3 ;

[0128] The coking mixture is fed into a tubular heater for heating, with steam injected at a ratio of 5 L / min to 100 kg of coking mixture. The heating process involves increasing the temperature from 485°C to 503°C at a rate of 0.5°C / h for 36 hours, yielding the heated coking mixture. This heated coking mixture is then fed into a pyrolysis reactor from the bottom, where the temperature is controlled at 470°C. The pyrolysis process involves gradually decreasing the pressure from 0.4 MPa to 0.16 MPa at a rate of 0.01 MPa / h for 24 hours, yielding petroleum coke precursors and high-temperature oil gas. This high-temperature oil gas, at 378°C, is discharged from the top of the pyrolysis reactor and then fed into the fractionation tower mentioned above, where it is distilled together with the heated heavy mixture.

[0129] The light wax oil fraction obtained from the side stream of the above-mentioned fractionation tower is heated to 500°C and then passed into a pyrolysis reactor to modify the petroleum coke precursor. The treatment time is 4 hours to obtain petroleum coke. The obtained petroleum coke is then cooled to 100°C by low-temperature steam and then cut out from the pyrolysis reactor by high-pressure water to obtain blocky petroleum coke.

[0130] Tests revealed that the petroleum coke contained 4% fine mosaic structure, 8% small flake structure, 45% large flake structure, 3% short fiber structure, 36% fine fiber structure, and 4% coarse fiber structure. The true density of the petroleum coke sampled from the top of the pyrolysis reactor was 1.55 g / cm³. 3 The true density of petroleum coke sampled from the bottom of the pyrolysis reactor was 1.56 g / cm³. 3 The volatile matter content of petroleum coke sampled from the upper part of the pyrolysis reactor was 10.2%, and the volatile matter content of petroleum coke sampled from the lower part of the pyrolysis reactor was 10%. Therefore, the petroleum coke has good homogeneity. The samples from the upper and lower parts of the pyrolysis reactor were mixed and tested. The results showed that, based on the total mass of petroleum coke (100%), the ash content was 0.018%, the sulfur content was 0.6%, and the nitrogen content was 0.2%.

[0131] The non-graphite carbon material precursor obtained by centrifugation was fed into a carbonization furnace and carbonized at 1400°C for 3 hours in a nitrogen atmosphere. Nitrogen was then introduced into the carbonization furnace for cooling. After cooling to room temperature, the non-graphite carbon material was obtained. The non-graphite carbon material was then pulverized using an air jet mill to obtain pulverized non-graphite carbon material with a D10 particle size of 1.9 μm, a D50 particle size of 8.6 μm, and a D90 particle size of 18 μm. The interlamellar spacing of the non-graphite carbon material was approximately 0.357 nm.

[0132] The petroleum coke is fed into a dryer and indirectly dried using steam at 150°C for 3 hours. Then, it is crushed into 1-2 mm particles by a coarse crusher (specifically a jaw crusher), and then further crushed and classified by a fine crusher (specifically an air jet mill) to obtain pulverized petroleum coke with a D10 particle size of 2.6 μm, a D50 particle size of 15.7 μm, and a D90 particle size of 21.8 μm.

[0133] The pulverized petroleum coke is fed into a liquid phase coating machine. The heavy wax oil fraction obtained from the side stream of the distillation tower is used as the coating agent. The coating agent is heated to 100°C and then pressurized to 3 MPa. The coating agent is then sprayed onto the pulverized petroleum coke being stirred through a nozzle with a diameter of 0.8 mm. The stirring speed is 500 r / min. The amount of coating agent used is 7% of the mass of the pulverized petroleum coke. The residence time of the pulverized petroleum coke in the liquid phase coating machine is 30 min. Nitrogen gas is then introduced into the liquid phase coating machine for cooling. After cooling to room temperature, petroleum coke with a coating layer is obtained.

[0134] The coated petroleum coke was fed into a carbonization furnace and heat-treated in a nitrogen atmosphere at a temperature of 700°C for 6 hours. Then, it was graphitized in a graphitization furnace in a nitrogen atmosphere at a temperature of 3000°C for 6 hours to obtain artificial graphite material with a D10 particle size of 2.6 μm, a D50 particle size of 15.7 μm, and a D90 particle size of 21.8 μm, consistent with the pulverized petroleum coke described above.

[0135] The artificial graphite material and the pulverized non-graphite material were added to a mixer at a mass ratio of 10:1 and mixed under stirring conditions. The stirring speed was 1200 r / min and the mixing time was 40 min to obtain the negative electrode material.

[0136] Lithium-ion button half-cells were prepared using the negative electrode material as described above.

[0137] Tests showed that the lithium-ion button half-cell prepared using the negative electrode material of this embodiment had an initial delithiation capacity of 440 mAh / g and an initial coulombic efficiency of 94%.

[0138] The structural schematic diagram of the preparation system used in the above embodiments is shown in Figure 1. The preparation system includes: a first heavy oil raw material storage tank 1, a second heavy oil raw material storage tank 2, a settling tank 3, an electric field deconsolidator 4, a first centrifuge 5, a blending tank 6, a nanoporous carbon storage tank 7, an online mixer 8, a second centrifuge 9, a first tubular heater 10, a fractionation tower 11, a second tubular heater 12, a pyrolysis reactor 13, a dryer 14, a coarse crusher 15, a fine crusher 16, a liquid phase coating machine 17, a first carbonization furnace 18, a graphitization furnace 19, a second carbonization furnace 20, a pulverizer 21, and a mixer 22; wherein, the blending tank 6 is equipped with at least an ultrasonic generator 601 and a data acquisition unit 602.

[0139] Comparative Example 1

[0140] This comparative example provides a negative electrode material, the preparation method of which includes the following steps:

[0141] Using the catalytic cracking slurry from Example 1 as the heavy oil feedstock, the heavy oil feedstock was fed into a settling tank, where a commercially available phenolic resin-based nonionic settling agent was added for settling and desolidification. The amount of settling agent added was 200 ppm by mass of the heavy oil feedstock, and the settling time was 10 hours, resulting in the obtained settled and desolidified heavy oil. The ash content of the settled and desolidified heavy oil was 800 ppm, the distillation range was 330–560°C, and the density (20°C) was 1.01 g / cm³. 3 Furthermore, taking the total mass of the heavy oil after sedimentation and solidification as 100%, the content of saturated fraction is 26%, aromatic fraction is 55%, gum content is 18%, asphaltenes content is 1%, sulfur content is 0.7%, nitrogen content is 0.2%, and residual carbon content is 11%.

[0142] The settled and desolidified heavy oil was fed into an electrically heated reactor for pyrolysis at a temperature of 505℃ and a pressure of 0.3MPa for 10 hours to obtain pyrolytic char. The pyrolytic char was then pulverized to obtain pulverized pyrolytic char with a D10 particle size of 3.2μm, a D50 particle size of 10.3μm, and a D90 particle size of 22.6μm.

[0143] The pulverized pyrolytic carbon and porous carbon nanotubes (specific surface area of ​​300 m²) were then mixed. 2 / g, pore size of 0.1~8nm, D50 particle size of 90nm) are mixed at a mass ratio of 100:1, and then solid-phase coating is carried out by epoxy resin. The amount of epoxy resin is 10% of the total mass of the pulverized pyrolytic carbon and porous carbon nanotubes. The coating temperature is 600℃ and the time is 5 hours to obtain pyrolytic carbon with a coating layer.

[0144] The pyrolytic carbon with a coating layer was carbonized in a nitrogen atmosphere at 1000°C for 3 hours to obtain the negative electrode material.

[0145] Lithium-ion button half-cells were prepared using the negative electrode material as described above.

[0146] Tests showed that the initial delithiation capacity of the lithium-ion button half-cell prepared using the negative electrode material in this comparative example was 230 mAh / g, and the initial coulombic efficiency was 76%.

[0147] Comparative Example 2

[0148] This comparative example is basically the same as Example 1, except that the heavy wax oil fraction obtained from the distillation tower side stream was not used as a coating agent to coat the petroleum coke in the liquid phase. The remaining steps and conditions are the same as in Example 1.

[0149] Tests showed that the initial delithiation capacity of the lithium-ion button half-cell prepared using the negative electrode material in this comparative example was 223 mAh / g, and the initial coulombic efficiency was 68%.

[0150] Comparative Example 3

[0151] This comparative example is basically the same as Example 1, except that the first and second heavy oil feedstocks in Example 1 are exchanged. That is, vacuum residue is used as the first heavy oil feedstock and catalytic cracking slurry is used as the second heavy oil feedstock. The desolidification steps and conditions are the same as in Example 1. The ash content of the first purified heavy oil is 150 ppm and the ash content of the second purified heavy oil is 270 ppm. The remaining steps and conditions are the same as in Example 1.

[0152] Tests showed that the initial delithiation capacity of the lithium-ion button half-cell prepared using the negative electrode material in this comparative example was 338 mAh / g, and the initial coulombic efficiency was 78%.

[0153] Comparative Example 4

[0154] This comparative example is basically the same as Example 1, except that the light waxy oil fraction obtained from the fractionation tower side stream was not used to modify the petroleum coke precursor. Instead, the petroleum coke precursor from Example 1 was directly used as the petroleum coke for subsequent steps. All other steps and conditions were the same as in Example 1. The true density and volatile matter content of the petroleum coke sampled from the upper and lower parts of the pyrolysis reactor differed significantly. The petroleum coke obtained in this comparative example exhibited lower structural order and poorer homogeneity.

[0155] Tests showed that the initial delithiation capacity of the lithium-ion button half-cell prepared using the negative electrode material in this comparative example was 390–420 mAh / g, and the initial coulombic efficiency was 85–90%. It should be noted that due to the poor homogeneity of the petroleum coke sample in this comparative example, the performance stability of the prepared battery was poor, exhibiting significant fluctuations.

[0156] Comparative Example 5

[0157] This comparative example is basically the same as Example 1, except that: nanoporous activated carbon was not used, and the first purified heavy oil and the second purified heavy oil were mixed online at a mass ratio of 1:10 to obtain a heavy mixed oil; then, the same distillation, pyrolysis and modification treatment as in Example 1 was performed to obtain petroleum coke.

[0158] Tests revealed that the petroleum coke contained 15% fine mosaic structure, 10% small flake structure, 32% large flake structure, 9% short fiber structure, 28% fine fiber structure, and 6% coarse fiber structure. The true density of the petroleum coke sampled from the top of the pyrolysis reactor was 1.478 g / cm³. 3 The true density of petroleum coke sampled from the bottom of the pyrolysis reactor was 1.482 g / cm³. 3 The volatile matter content of petroleum coke sampled from the upper part of the pyrolysis reactor was 9.5%, and the volatile matter content of petroleum coke sampled from the lower part of the pyrolysis reactor was 9.2%. The samples from the upper and lower parts of the pyrolysis reactor were mixed, and the results showed that, based on the total mass of petroleum coke (100%), the ash content was 0.04%, the sulfur content was 0.9%, and the nitrogen content was 0.3%. Subsequently, artificial graphite material was prepared as the negative electrode material using the same steps and conditions as in Example 1.

[0159] Tests showed that the initial delithiation capacity of the lithium-ion button half-cell prepared using the negative electrode material in this comparative example was 335 mAh / g, and the initial coulombic efficiency was 88%.

[0160] Comparative Example 6

[0161] This comparative example is essentially the same as Example 1, except that: the second purified heavy oil is introduced into a mixing tank equipped with an ultrasonic generator, and nanoporous activated carbon is added. After mixing under intermittent ultrasonic waves, a second purified heavy oil containing nanoporous carbon is obtained. The third purified heavy oil in the upper layer of the mixing tank and the heavy oil containing nanoporous carbon in the lower layer are not separated. The nanoporous activated carbon used and its dosage, as well as the power and intermittent setting of the ultrasonic waves, are the same as in Example 1. Subsequently, the second purified heavy oil containing nanoporous carbon and the first purified heavy oil are mixed online at a mass ratio of 1:10 to obtain a heavy mixed oil. The online mixing temperature and linear velocity are the same as in Example 1. Then, the heavy mixed oil is heated and distilled under the same conditions as in Example 1 to obtain coking mixed oil; the coking mixed oil is then heated, pyrolyzed and modified under the same conditions as in Example 1 to obtain petroleum coke; the petroleum coke is then dried, pulverized, liquid-phase coated, heat-treated and graphitized under the same conditions as in Example 1 to obtain artificial graphite material, which is used as the negative electrode material.

[0162] Lithium-ion button half-cells were prepared using the negative electrode material as described above.

[0163] In this comparative example, the heavy oil containing nanoporous carbon was not separated and used separately, but rather mixed with the first purified heavy oil. During the preparation of petroleum coke, the nanoporous carbon formed several carbon microcrystal nuclei, and the system rapidly generated a large number of mesophase microcrystals, increasing viscosity and producing petroleum coke dominated by microcrystals. Therefore, it was impossible to prepare non-graphite structured carbon materials. Tests showed that the initial delithiation capacity of the lithium-ion button half-cell prepared using the negative electrode material of this comparative example was 332 mAh / g, and the initial coulombic efficiency was 90%.

[0164] Comparative Example 7

[0165] This comparative example is basically the same as Example 1, except that the heavy oil containing nanoporous carbon is separated by sedimentation (gravity sedimentation) instead of centrifugation. The sedimentation time is 24 hours and the temperature is 50°C, resulting in a non-graphite carbon material precursor in the lower layer and a fourth purified heavy oil in the upper layer. The remaining steps and conditions are the same as in Example 1.

[0166] Because the nanoporous carbon is well distributed in the system, the upper layer of purified heavy oil after sedimentation still contains nanoporous carbon, which subsequently affects the formation of petroleum coke structure and reduces the role of non-graphite carbon materials. Tests showed that the initial delithiation capacity of the lithium-ion button half-cell prepared using the negative electrode material of this comparative example was 358 mAh / g, and the initial coulombic efficiency was 90%.

[0167] Comparative Example 8

[0168] This comparative example is basically the same as Example 1, except that the first heavy oil feedstock is not used; only the second heavy oil feedstock is used. Therefore, after mixing all the third purified heavy oil and all the fourth purified heavy oil, a heavy mixed oil is obtained. The remaining steps and conditions are the same as in Example 1.

[0169] In this comparative example, since the first heavy oil feedstock was not involved, the petroleum coke was generated entirely from the second heavy oil feedstock. This altered the viscosity of the petroleum coke formation system, affecting the formation of the ordered structure. Tests showed that the lithium-ion button half-cell prepared using the negative electrode material of this comparative example exhibited an initial delithiation capacity of 352 mAh / g and an initial coulombic efficiency of 89%.

Claims

1. A method for preparing petroleum coke, non-graphite carbon materials, and anode materials, comprising the following steps: (1) The first heavy oil raw material is subjected to a first desolidification treatment to obtain a first purified heavy oil; the second heavy oil raw material is subjected to a second desolidification treatment to obtain a second purified heavy oil; (2) The second purified heavy oil is mixed with nanoporous carbon to obtain a third purified heavy oil in the upper layer and a heavy oil containing nanoporous carbon in the lower layer; (3) The heavy oil containing nanoporous carbon is subjected to solid-liquid separation to obtain a non-graphite carbon material precursor and a fourth purified heavy oil; (4) The third purified heavy oil is subjected to solid-liquid separation to obtain a non-graphite carbon material precursor and a fourth purified heavy oil; (5) The heavy oil, the fourth purified heavy oil, and the first purified heavy oil are mixed to obtain a heavy mixed oil; (6) The heavy mixed oil is distilled to obtain a coking mixed oil; (7) The coking mixed oil is pyrolyzed to obtain a petroleum coke precursor; (8) The petroleum coke precursor is modified to obtain the petroleum coke; (9) The non-graphite carbon material precursor is carbonized to obtain the non-graphite carbon material; (10) A negative electrode material is prepared using the petroleum coke and the non-graphite carbon material.

2. The method for preparing petroleum coke, non-graphite carbon materials, and negative electrode materials according to claim 1, wherein, In step (1), based on the total mass of the first heavy oil feedstock as 100%, the saturated content is 10-17%, the aromatic content is 55-75%, the resin content is 10-18%, the asphaltenes content is 1-10%, the sulfur content is 0.3-1.2%, the nitrogen content is 0.1-0.5%, and the residual carbon content is 13-20%; the density of the first heavy oil feedstock at 20°C is 0.97-1.04 g / cm³. 3 The dynamic viscosity at 130℃ is 0.3~0.4Pa·s; and the ash content of the first heavy oil feedstock is 2000~5000ppm.

3. The method for preparing petroleum coke, non-graphite carbon materials, and negative electrode materials according to claim 1, wherein, In step (1), the first deconsolidation treatment includes one or both of sedimentation deconsolidation and electric field deconsolidation; the sedimentation deconsolidation includes: adding a sedimentation agent to the first heavy oil raw material for deconsolidation treatment, the sedimentation agent including a phenolic resin nonionic sedimentation agent, the amount of sedimentation agent added being 200-400 ppm of the mass of the first heavy oil raw material, the sedimentation time being 3-10 hours, to obtain sedimentation-deconsolidated heavy oil; the electric field deconsolidation includes: passing the first heavy oil raw material or the sedimentation-deconsolidated heavy oil through a filter containing packing material under the action of an electric field, the strength of the electric field being 4-7 kV / m, the flow rate of the first heavy oil raw material or the sedimentation-deconsolidated heavy oil through the filter containing packing material being 0.1-0.3 m / s, to obtain electric field-deconsolidated heavy oil; the ash content of the first purified heavy oil is 40-80 ppm.

4. The method for preparing petroleum coke, non-graphite carbon materials, and negative electrode materials according to claim 1, wherein, In step (1), based on the total mass of the second heavy oil feedstock as 100%, the saturated content is 0.2-28%, the aromatic content is 40-75%, the resin content is 4-30%, the asphaltenes content is 3-30%, the sulfur content is 0.05-0.6%, the nitrogen content is 0.01-0.4%, and the residual carbon content is 13-20%; the density of the second heavy oil feedstock at 20°C is 1.05-1.18 g / cm³. 3 The dynamic viscosity at 130℃ is 0.5–0.8 Pa·s; and the ash content of the second heavy oil feedstock is 300–2000 ppm.

5. The method for preparing petroleum coke, non-graphite carbon materials, and negative electrode materials according to claim 1, wherein, In step (1), the second deconsolidation process includes centrifugal deconsolidation, wherein the temperature of the centrifugal deconsolidation is 130-150°C and the rotation speed is 3000-4000 rpm; the ash content of the second purified heavy oil is 10-100 ppm.

6. The method for preparing petroleum coke, non-graphite carbon materials, and negative electrode materials according to claim 1, wherein, Step (2) includes: mixing the second purified heavy oil with nanoporous carbon under the action of intermittently set ultrasound, wherein the power of the ultrasound is 350-400W / L, and the intermittent setting method includes: making the ultrasound for 20-30 seconds, then stopping for 20-30 seconds, then making the ultrasound for 20-30 seconds, then stopping for 20-30 seconds, and so on, to obtain the third purified heavy oil in the upper layer and the heavy oil containing nanoporous carbon in the lower layer.

7. The method for preparing petroleum coke, non-graphite carbon materials, and negative electrode materials according to claim 1, wherein, In step (2), the specific surface area of ​​the nanoporous carbon is 200–1800 m². 2 / g, with a pore size of 0.1-10nm, a D50 particle size of 10-100nm, and the nanoporous carbon having a mass content of 200-500ppm in the second purified heavy oil.

8. The method for preparing petroleum coke, non-graphite carbon materials, and negative electrode materials according to claim 7, wherein, The nanoporous carbon includes one or more of porous graphene, porous carbon nanotubes, and nanoporous activated carbon.

9. The method for preparing petroleum coke, non-graphite carbon materials, and negative electrode materials according to claim 1, wherein, In step (3), the solid-liquid separation of the heavy oil containing nanoporous carbon includes centrifugal separation, wherein the centrifugal separation speed is 1000-1500 r / min and the temperature is 50-70℃.

10. The method for preparing petroleum coke, non-graphite carbon materials, and negative electrode materials according to claim 1, wherein, In step (4), the mixing mass ratio of the third purified heavy oil and the fourth purified heavy oil is (6-9):(4-0.5), and the mixing mass ratio of the total amount of the first purified heavy oil, the third purified heavy oil and the fourth purified heavy oil is (1-5):10; the mixing is carried out online, and the online mixing temperature is 100-150℃ and the linear velocity is 0.3-0.5m / s.

11. The method for preparing petroleum coke, non-graphite carbon materials, and negative electrode materials according to claim 1, wherein, Step (5) includes: heating the heavy mixed oil to obtain heated heavy mixed oil; then performing vacuum distillation on the heated heavy mixed oil to obtain coking mixed oil; wherein the temperature of the heated heavy mixed oil is 350-370℃; the vacuum distillation is carried out using a fractionating column, the pressure inside the fractionating column is controlled at 20-50KPa, the upper temperature of the fractionating column is 120-150℃ and the lower temperature is 360-380℃, and the coking mixed oil is obtained at the bottom of the fractionating column.

12. The method for preparing petroleum coke, non-graphite carbon materials, and negative electrode materials according to claim 1, wherein, In step (5), the coking blend oil has a distillation range of 350–680°C and a density of 1.0–1.1 g / cm³ at 20°C. 3 Based on the total mass of the coking blend oil as 100%, the saturated content is 2-22%, the aromatic content is 50-80%, the gum content is 5-22%, the asphaltenes content is 5-22%, the sulfur content is 0.1-0.6%, the nitrogen content is 0.01-0.4%, and the residual carbon content is 5-15%.

13. The method for preparing petroleum coke, non-graphite carbon materials, and negative electrode materials according to claim 11, wherein, In step (5), the fractionation tower obtains gasoline, diesel, light wax oil, and heavy wax oil fractions through measuring lines; wherein the density of the gasoline at 20°C is 0.76–0.78 g / cm³. 3 The diesel fuel has a density of 0.80–0.85 g / cm³ at 20°C. 3 The light wax oil fraction has a density of 0.86–0.87 g / cm³ at 20°C. 3 The density of the heavy wax oil fraction at 20°C is 0.88–0.89 g / cm³. 3 .

14. The method for preparing petroleum coke, non-graphite carbon materials, and negative electrode materials according to claim 1, wherein, Step (6) includes: heating the coking mixture and injecting steam during the heating process to obtain heated coking mixture; then pyrolyzing the heated coking mixture to obtain petroleum coke precursor and high-temperature oil gas; wherein the ratio of the steam flow rate to the mass of the coking mixture is: 1-5 L / min steam: 100 kg coking mixture; the temperature of the heated coking mixture is 480-510℃; the pyrolysis temperature is 420-470℃, the time is 24-48 hours, and the pressure is 0.1-0.7 MPa.

15. The method for preparing petroleum coke, non-graphite carbon materials, and negative electrode materials according to claim 14, wherein, Step (6) further includes: distilling the high-temperature oil and gas together with the heavy mixed oil in step (5); the temperature of the high-temperature oil and gas is 370-410°C.

16. The method for preparing petroleum coke, non-graphite carbon materials, and negative electrode materials according to claim 13, wherein, In step (7), the modification treatment includes: heating the light wax oil fraction obtained in step (5) to 480-510°C, and then passing it into the petroleum coke precursor for modification treatment for 3-6 hours.

17. The method for preparing petroleum coke, non-graphite carbon materials, and negative electrode materials according to claim 1, wherein, In step (8), the carbonization temperature is 1000-1400°C and the time is 3-6 hours.

18. The method for preparing petroleum coke, non-graphite carbon materials, and negative electrode materials according to claim 1, wherein, Step (9) includes: (9)-1. After crushing, liquid-phase coating, heat treatment and graphitization of the petroleum coke, artificial graphite material is obtained; (9)-2. The artificial graphite material and the non-graphite carbon material are mixed to obtain the negative electrode material.

19. The method for preparing petroleum coke, non-graphite carbon materials, and negative electrode materials according to claim 18, wherein, In step (9)-1, the liquid phase coating includes: using the heavy wax oil fraction of claim 13 as a coating agent, heating the coating agent to 50-100°C, then pressurizing it to 2-3 MPa, and then spraying the coating agent onto the pulverized petroleum coke being stirred through a spray head. The diameter of the spray head is 0.5-1 mm, the stirring speed is 500-1000 r / min, and the amount of the coating agent is 1-10% of the mass of the pulverized petroleum coke, thereby obtaining petroleum coke with a coating layer.

20. The method for preparing the negative electrode material according to claim 18, wherein, In step (9)-1, the heat treatment temperature is 700-900℃ and the time is 4-6 hours; the graphitization temperature is 2950-3100℃ and the time is 4-12 hours.

21. The method for preparing the negative electrode material according to claim 18, wherein, In step (9)-1, the D10 particle size of the artificial graphite material is 2-3 μm, the D50 particle size is 14-16 μm, and the D90 particle size is 21-23 μm.

22. The method for preparing the negative electrode material according to claim 18, wherein, In step (9)-2, the D10 particle size of the non-graphite carbon material is 1-2 μm, the D50 particle size is 7-9 μm, and the D90 particle size is 16-18 μm.

23. The method for preparing the negative electrode material according to claim 18, wherein, In step (9)-2, the mass ratio of the artificial graphite material to the non-graphite carbon material is 10:(0.1~1).

24. A type of petroleum coke, which is prepared by the method of any one of claims 1-23, comprising the petroleum coke, the non-graphite carbon material, and the negative electrode material; wherein, The petroleum coke contains 1-5% fine mosaic structure, 5-10% small flake structure, 40-60% large flake structure, 3-8% short fiber structure, 25-40% fine fiber structure, and 2-12% coarse fiber structure; and / or, the true density of the petroleum coke is 1.4-1.6 g / cm³. 3 Furthermore, based on the total mass of the petroleum coke as 100%, the volatile matter content is 8-12%, the ash content is 0.01-0.02%, the sulfur content is 0.5-1%, and the nitrogen content is 0.1-0.3%.

25. A non-graphite carbon material, which is prepared by the method of any one of claims 1-23 for preparing petroleum coke, non-graphite carbon material and negative electrode material.

26. A negative electrode material, which is prepared by the method of any one of claims 1-23 for preparing petroleum coke, non-graphite carbon material and negative electrode material.

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