Production process and production system of negative electrode coke and mesophase pitch

Abstract

The invention discloses a production process and a production system of negative electrode coke and mesophase pitch, the production process comprises the following steps: (1) treating a raw material A under a heat treatment condition, and separating a liquid-phase material flow obtained after treatment to obtain a material flow A and a material flow B; (2) reacting the material flow A with an auxiliary agent to obtain a material flow C, and further reacting in the presence of carrier gas to obtain mesophase pitch and a material flow D; (3) the material flow D enters a coking unit, and negative electrode coke and a material flow E are obtained after the coking reaction is completed; (4) treating the raw material B under a heat treatment condition to obtain asphalt containing mesophase pellets and a material flow F; and (5) the material flow E and the material flow F enter a separation unit, and gas, a material flow G, a material flow H and a material flow I are obtained after separation. On one hand, high value-added utilization of the raw materials can be realized, and on the other hand, different carbon material products can be obtained at the same time.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon-based materials, and in particular relates to a production process and system for negative electrode coke and mesophase asphalt. Background Art

[0002] With the vigorous development of the new energy industry and the rapid update and iteration of consumer electronic products, the lithium-ion battery industry has also ushered in a broad prospect. In recent years, as people's requirements for battery performance have become higher and higher, the demand for high-performance, low-cost negative electrode materials will become a future development trend.

[0003] CN 113716544 A discloses a method for preparing low-cost high-rate negative electrode material coke, wherein clean asphalt is obtained by cutting the components of coal-based soft asphalt, and the clean asphalt is mixed with deacidified and dried carbon particles and subjected to thermal reaction to obtain negative electrode coke.

[0004] CN 116072833 A discloses a high-capacity fast-charging negative electrode coke and a preparation method thereof. The high-capacity fast-charging negative electrode coke is obtained by adding blending materials, silicon dioxide or nano silicon to coal tar pitch and reacting.

[0005] CN 115180612 A discloses a high energy density negative electrode coke production process, wherein raw material oil and a nucleating agent, namely needle coke fine powder, are mixed and coked to obtain high energy density negative electrode coke.

[0006] Mesophase pitch is a high-quality carbon material precursor made from coal, petroleum, high molecular polymers, and other aromatic compounds. It has been widely used in the preparation of needle coke, foamed carbon, high-performance pitch-based carbon fibers and other carbon materials. High-performance pitch-based carbon fibers are widely used in the aerospace field because of their high strength, high modulus, electrical and thermal conductivity and other excellent properties.

[0007] CN112831334A and CN112645304A disclose a method for preparing mesophase asphalt and mesophase carbon microspheres, which use heavy oil as raw material, extract with n-heptane, then dope organic metal complexes / biomass materials into the deasphalted oil for shallow catalysis, add free radical additives to the heavy components obtained by vacuum distillation of the product, and prepare mesophase asphalt and mesophase carbon microspheres.

[0008] CN 114989851A discloses a foamed carbon precursor, petroleum foamed carbon and a preparation method thereof, wherein ethylene tar is used as a raw material, and a mesophase asphalt having a small domain type optical texture is prepared through component separation and thermal polymerization process.

[0009] CN108441244A discloses a preparation method of mesophase carbon microspheres and mesophase pitch. The co-carbonization raw material obtained by mixing coal-based pitch with a first solvent is subjected to a first thermal polycondensation reaction, then a second solvent is added and mixed, dissolved, and the solid component obtained after separation is dried to obtain mesophase carbon microspheres, and the liquid component is distilled and subjected to a second thermal polycondensation reaction to obtain mesophase pitch.

[0010] Ethylene tar is mainly composed of polycyclic aromatic hydrocarbons and aromatic olefins, with low contents of heteroatoms such as sulfur and nitrogen. It has a wide source and low cost, and is a raw material for preparing high-quality carbon materials such as mesophase pitch, mesophase carbon microspheres, and anode coke. However, its initial coking temperature is relatively low. When directly preparing mesophase pitch from ethylene tar, coke is easily generated, seriously affecting the quality of the product; when directly preparing anode coke from ethylene tar, coking of the heating furnace tubes is likely to occur, affecting the operation of the device. Therefore, in the process of preparing mesophase pitch and anode coke from ethylene tar, how to ensure the quality of mesophase pitch and anode coke products and ensure the normal operation of the device is a technical problem to be solved in this field currently. Summary of the Invention

[0011] The present invention provides a production method and a production system for anode coke and mesophase pitch. The main purpose is to solve the problems existing in the prior art. On the one hand, high-value utilization of raw materials can be achieved, and on the other hand, different carbon material products can be obtained simultaneously.

[0012] The first aspect of the present invention provides a production process for anode coke and mesophase pitch. The production process includes the following steps:

[0013] (1) Treat raw material A under heat treatment conditions. After treatment, the obtained liquid-phase material flow is further separated to obtain material flow A and material flow B;

[0014] (2) Under contacting conditions, material flow A reacts with an auxiliary agent to obtain material flow C;

[0015] (3) The material flow C obtained in step (2) further reacts in the presence of a carrier gas to obtain mesophase pitch and material flow D;

[0016] (4) Material flow D enters a coking unit, and after the coking reaction is completed, anode coke and material flow E are obtained;

[0017] (5) Treat raw material B under heat treatment conditions to obtain pitch containing mesophase spheres and material flow F;

[0018] (6) Material flow E and material flow F enter a separation unit, and after separation, gas, material flow G, material flow H, and material flow I are obtained.

[0019] Further, as some specific embodiments, the material flow I in step (6) enters the coking unit and undergoes a coking reaction by mixing with the material flow D.

[0020] Further, as some specific embodiments, the material flow H in step (6) is mixed with the material flow C for treatment.

[0021] Further, as some specific embodiments, the raw material A in step (1) can be selected from one or more of ethylene tar, butadiene tar, high-temperature coal tar, etc., and is preferably ethylene tar.

[0022] Further, as some specific embodiments, the heat treatment conditions in step (1) can generally be controlled as follows: the heat treatment pressure is 0.01 - 10 MPa, preferably 0.5 - 5 MPa; the heat treatment temperature is 120 - 240 °C, preferably 130 - 220 °C; the residence time is 0.1 - 12 h, preferably 0.5 - 6 h.

[0023] Further, as some specific embodiments, the heat treatment mentioned in step (1) is carried out under the protection of an inert atmosphere, and the inert atmosphere is nitrogen and / or an inert gas, preferably nitrogen; the inert gas can be one or more of helium, neon, argon, krypton, and xenon.

[0024] Preferably, in the co-production process of the above mesophase pitch and mesophase carbon microspheres, the method for separating the liquid-phase material flow obtained after the heat treatment in step (1) can be one or more of flash distillation, steam stripping, atmospheric distillation, vacuum distillation, etc., and is preferably carried out by vacuum distillation.

[0025] Further, as some specific embodiments, the 95% distillation temperature of the material flow A in step (1) is 460 - 540 °C, preferably 460 - 500 °C.

[0026] Further, as some specific embodiments, the heat treatment in step (1) can optionally use or not use a catalyst, and is preferably to use a catalyst; the catalyst can be anhydrous aluminum chloride, and the addition amount of the catalyst is 1 wt% - 10 wt% of the weight of the raw material A, preferably 2 wt% - 5 wt%.

[0027] Further, as some specific embodiments, the auxiliary agent in step (2) is a compound containing at least one aromatic ring. Specific auxiliary agents can be selected from one or more of methylnaphthalene, xylene, 1,2,4,5-tetramethylbenzene, tetrahydronaphthalene, decahydronaphthalene, anthracene, and dihydroanthracene, and is preferably tetrahydronaphthalene. Further, the weight ratio of the auxiliary agent to the material flow A is 1:100 - 50:100, preferably 10:100 - 30:100.

[0028] Further, as some specific embodiments, the reaction conditions in step (2) are as follows: the reaction temperature is 360 - 500 °C, preferably 360 - 460 °C; the reaction pressure is atmospheric pressure - 5 MPa, preferably 0.1 - 3 MPa; the residence time of the material in the reactor is 1 - 20 h, preferably 2 - 10 h.

[0029] Further, as some specific embodiments, the reaction conditions in step (3) are as follows: the pressure at the top of the reactor is 20 Pa - 1000 kPa (absolute pressure), preferably 20 Pa - 500 kPa (absolute pressure); the reaction temperature is 350 - 500 °C, preferably 360 - 460 °C, and the residence time is 6 - 15 h, preferably 6 - 12 h.

[0030] Further, as some specific embodiments, the carrier gas in step (3) can be one or more of water vapor, nitrogen, hydrogen, and inert gas, preferably water vapor or nitrogen; wherein the inert gas is one or more of helium, neon, argon, krypton, and xenon.

[0031] Further, as some specific embodiments, the operating conditions of the coking unit in step (4) are as follows: the heating furnace adopts variable temperature control, and the variable temperature range is 440 - 510 °C, preferably 450 - 500 °C; the coke charging cycle is 20 - 30 h.

[0032] Further, as some specific embodiments, the heat treatment conditions in step (5) are as follows: the heat treatment pressure is atmospheric pressure - 5 MPa, preferably atmospheric pressure - 3 MPa; the heat treatment temperature is 360 - 480 °C, preferably 380 - 450 °C; the heat treatment time is 4 - 60 h, preferably 8 - 48 h.

[0033] Further, as some specific embodiments, the stream B obtained in step (1) is mixed with the raw material B for heat treatment.

[0034] Further, as some specific embodiments, the raw material B in step (5) is first subjected to a first-stage heat treatment alone, and then introduced into the stream B and mixed for a second-stage heat treatment together.

[0035] Further, as some specific embodiments, the first-stage heat treatment conditions are as follows: the first-stage heat treatment pressure is atmospheric pressure - 5 MPa, preferably 1 - 3 MPa; the first-stage heat treatment temperature is 380 - 480 °C, preferably 400 - 450 °C; the first-stage heat treatment time is 2 - 20 h, preferably 4 - 12 h.

[0036] Further, as some specific embodiments, the conditions of the second-stage heat treatment are as follows: the pressure of the second-stage heat treatment is from atmospheric pressure to 1 MPa, preferably from atmospheric pressure to 0.5 MPa; the temperature of the second-stage heat treatment is 360 to 480 °C, preferably 380 to 450 °C; the time of the second-stage heat treatment is 2 to 48 h, preferably 4 to 36 h.

[0037] Further, as some specific embodiments, the raw material B in step (5) can be one or more of catalytic slurry, petroleum asphalt, coal tar pitch, coal liquefaction residue, etc., and is preferably catalytic slurry.

[0038] Further, as some specific embodiments, the pitch containing mesophase spheres obtained in step (5) is further subjected to hot filtration, solvent extraction, washing, and drying to obtain mesophase carbon microspheres.

[0039] Further, as some specific embodiments, the pitch containing mesophase spheres obtained in step (5) is first cooled to room temperature, and then added to a dispersion medium for hot filtration treatment to concentrate the mesophase spheres. Then, it is extracted with a solvent until the solvent in the extractor is colorless and transparent, and then washed and dried to obtain mesophase carbon microspheres.

[0040] Further, as some specific embodiments, the dispersion medium is a hydrocarbon-containing compound, specifically one or several of diesel oil, anthracene oil, naphthalene oil, etc.; the hot filtration temperature is 200 to 250 °C, and the filtration time is 1 to 4 h.

[0041] Further, as some specific embodiments, the solvent used for solvent extraction is one or several of pyridine, quinoline, and toluene, and quinoline is preferred.

[0042] Further, as some specific embodiments, the washing is to repeatedly rinse the solid phase material rich in mesophase carbon microspheres extracted with a solvent with acetone 2 to 3 times to wash away the residual organic solvent in the solid phase material.

[0043] Further, as some specific embodiments, the drying conditions are as follows: the drying temperature is 80 to 120 °C, and the drying time is 8 to 24 h.

[0044] Further, as some specific embodiments, the cutting temperature of the material stream G and the material stream H in step (5) is 230 to 250 °C, preferably 230 to 240 °C; the cutting temperature of the material stream H and the material stream I is 410 to 430 °C, preferably 410 to 420 °C.

[0045] The second aspect of the present invention provides a mesophase pitch obtained by the above production process.

[0046] Further, as some specific embodiments, the softening point of the mesophase pitch is 270 to 310 °C, and the mesophase morphology presents a wide-area optical structure.

[0047] In the third aspect of the present invention, a method for preparing carbon fiber is provided. The content of the preparation method is as follows: The mesophase pitch obtained from the above production process is used as a raw material and sent to a spinning machine for spinning. The carbon fiber obtained by spinning can be processed through pre-oxidation, carbonization, and graphitization to obtain a carbon fiber product.

[0048] Furthermore, in the above method for preparing carbon fiber, any one of the existing mature processes in the art can be used for the spinning, pre-oxidation, carbonization, and graphitization processes, and the specific operating conditions can be freely selected and adjusted according to needs.

[0049] In the above method for preparing carbon fiber, the spinning process is generally melt spinning, and the spinning temperature is 30 - 50°C higher than the softening point; the pre-oxidation medium is air, the pre-oxidation temperature is 250°C, and the pre-oxidation time is 2 h; the carbonization and graphitization processes are carried out in an inert atmosphere. The carbonization temperature is 1100°C, and the carbonization time is 1 h; the graphitization temperature is 2500°C, and the graphitization time is 15 min.

[0050] In the fourth aspect of the present invention, a production system for negative electrode coke and mesophase pitch is provided. The production system includes a pretreatment unit, reaction unit A, reaction unit B, reaction unit C, a coking unit, separation unit A, and separation unit B; where:

[0051] The pretreatment unit heat-treats raw material A in the presence of an optional catalyst, and after heat-treatment, a gas-phase stream and a liquid-phase stream are obtained.

[0052] Separation unit A separates the liquid-phase stream from the pretreatment unit to obtain stream A and stream B.

[0053] Reaction unit A: Stream A from separation unit A reacts with an auxiliary agent, and after the reaction is completed, stream C is obtained.

[0054] Reaction unit B: In the presence of a carrier gas, stream C from reaction unit A reacts with the carrier gas, and after the reaction is completed, mesophase pitch and stream D are obtained.

[0055] The coking unit: Stream D from reaction unit B enters the coking unit for coking reaction, and after the reaction is completed, negative electrode coke and stream E are obtained.

[0056] Reaction unit C is used to receive raw material B and heat-treat raw material B in an inert atmosphere to obtain pitch containing mesophase spheres and stream F.

[0057] Separation unit B is used to receive and separate stream E from the coking unit and stream F from reaction unit C, and after separation, gas, stream G, stream H, and stream I are obtained.

[0058] Further, as some specific embodiments, the material stream B obtained by the separation unit A is connected to the inlet of the reaction unit C through a pipeline.

[0059] Further, as some specific embodiments, the material stream I obtained by the separation unit B is connected to the inlet of the coking unit through a pipeline, and the material stream I is mixed with the material stream D to carry out the coking reaction together.

[0060] Further, as some specific embodiments, the material stream H obtained by the separation unit B is connected to the inlet of the reaction unit B through a pipeline, and the material stream H is mixed with the material stream C for treatment.

[0061] Further, as some specific embodiments, the material stream G obtained by the separation unit B is connected to the pretreatment unit through a pipeline and is mixed with the raw material A for heat treatment.

[0062] Further, as some specific embodiments, the separation unit A and the separation unit B adopt equipment with the function of separating liquid-phase materials, which can be at least one of settings such as flash tanks and fractionating towers, and preferably a fractionating tower. The specific type of the fractionating tower can be selected according to needs.

[0063] The production process and production system of the negative electrode coke and mesophase pitch provided by the present invention have one or more of the following beneficial effects:

[0064] 1. The present invention uses heavy oils such as ethylene tar and catalytic slurry as raw materials. The raw materials are easily obtained and have low prices. Three carbon materials, namely negative electrode coke, mesophase pitch, and mesophase carbon microspheres, can be co-produced, and the process is simple, waste-free, and the product has high added value.

[0065] 2. In the production system provided by the present invention, the heavy fraction oil obtained by the separation unit B is an aromatic-rich oil with relatively high thermal stability. Entering the reaction unit B can regulate the viscosity of the reaction system. At the same time, as a co-carbonizing agent, this component can effectively improve the domain size in the microstructure of the mesophase pitch, which is beneficial to the formation and development of the wide-domain mesophase.

[0066] 3. In the production system provided by the present invention, through the compounding and synergistic action of the ethylene tar system and the catalytic slurry system, combined with the variable-temperature operation during the coking process, the coke product can have both capacity and rate performance.

[0067] 4. In the production system provided by the present invention, the material stream B obtained by the separation unit A enters the reaction unit C and reacts synergistically with the raw material B in the reaction unit C. The material stream B can not only act as a nucleating agent to promote the formation of mesophase spheres, but also act as a viscosity regulator to weaken the coalescence between the spheres, making the particle size distribution of the obtained mesophase spheres more uniform.

[0068] 5. In the production system provided by the present invention, in the pretreatment unit, preferably under the action of a catalyst, the easily coking components undergo a condensation reaction to remove the coking precursors. The liquid-phase material obtained after pretreatment flows through the separated stream A, and its carbon-carbon double bond content has been greatly reduced compared to the untreated ethylene tar raw material, and its thermal stability has been significantly improved, avoiding problems such as poor product uniformity and spinnability caused by directly using ethylene tar as a raw material to prepare mesophase pitch; the obtained mesophase pitch has high quality, its softening point can be adjusted between 270 - 330 °C, and the mesophase content is greater than 95%. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 It is a schematic diagram of the production process and production system of the negative electrode coke and mesophase pitch of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0070] The method of the present invention will be further described in detail below in conjunction with the drawings and embodiments, but the following embodiments do not limit the method of the present invention.

[0071] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0072] In this article, the negative electrode coke refers to the raw material coke for the battery negative electrode material, especially the raw material coke for the lithium battery negative electrode material.

[0073] The description of the exemplary embodiments is intended to be read in conjunction with the drawings, which are considered to be a part of the entire written description. In the specification, relative terms such as "lower", "upper", "horizontal", "vertical", "above", "below", "upward", "downward", "top" and "bottom" and their derivatives (e.g., "horizontally", "downwardly", "upwardly", etc.) should be interpreted as the directions shown in the drawings described at that time. These relative terms are for ease of description and do not require the device to be constructed or operated in a specific orientation. Unless otherwise specified, the "connection" described in the present invention refers to a relationship in which structures are directly or indirectly fixed or connected to each other through intermediate structures.

[0074] The present invention provides a production process and production system for negative electrode coke and mesophase pitch. The following is combined with the attached Figure 1The specific process of the production process is introduced as follows: Raw material A1 enters the pretreatment unit 2 and undergoes heat treatment in the presence of an optional catalyst. After heat treatment, a gas-phase stream 3 and a liquid-phase stream 4 are obtained. The liquid-phase stream 4 enters the separation unit A5, and after separation, a stream A6 and a stream B7 are obtained. The stream A6 enters the reaction unit A8, contacts with an auxiliary agent and undergoes a reaction. The obtained stream C9 after the reaction completion enters the reaction unit B10 and undergoes a reaction in the presence of a carrier gas 12. After the reaction, mesophase pitch 13 and a stream D11 are obtained. Among them, the generated mesophase pitch 13 is discharged from the bottom of the reaction unit B10 and can enter the subsequent spinning unit for further treatment. The stream D11 enters the coking unit 23 for coking reaction, and after the reaction completion, negative electrode coke and a stream E24 are obtained. The raw material B19 and the stream B7 (preferably, the raw material B first undergoes a one-stage heat treatment alone and then undergoes a two-stage heat treatment together with the introduced stream B) enter the reaction unit C20 and undergo heat treatment under the protection of an inert atmosphere. After the reaction, pitch containing mesophase microspheres 22 and a stream F21 are obtained. The stream E24 and the stream F21 enter the separation unit B14, and after separation, a gas 15, a stream G16, a stream H17, and a stream I18 are obtained. The stream G16 can be recycled back to the pretreatment unit 2 for treatment together with the raw material A1 (not shown in the figure). The stream H17 can be recycled back to the reaction unit B10 for treatment together with the stream C9. The stream I18 enters the coking unit 23 and undergoes a coking reaction together with the stream D11 to produce negative electrode coke. The pitch containing mesophase microspheres 22 obtained from the reaction unit C20 is subjected to hot filtration, solvent washing, and drying to obtain mesophase carbon microspheres.

[0075] In this article, the specific process for producing carbon fiber from mesophase pitch is as follows: First, the mesophase pitch enters a spinning machine for melt spinning. The spinning temperature is 30 - 50 °C higher than the softening point. The pre-oxidation medium is air, the pre-oxidation temperature is 250 °C, and the pre-oxidation time is 2 h. Carbonization and graphitization treatments are carried out in an inert atmosphere. The carbonization temperature is 1100 °C, and the carbonization time is 1 h. The graphitization temperature is 2500 °C, and the graphitization time is 15 min.

[0076] In this article, the strength of the carbon fiber is measured by the standard method of GB / T 31290 - 2014. The particle size distribution of the mesophase carbon microspheres is measured by the standard method of GB / T 19077 - 2016.

[0077] In this article, the performance evaluation test process of the negative electrode coke is as follows. The negative electrode coke is fed into a calcination furnace and calcined at 1300 °C for 5 hours, and the heating rate of the calcination furnace is 100 °C / h; then graphitization treatment is carried out at 2800 °C for 1 hour. For the sample after graphitization treatment, the assembly of the half-cell and the inspection of the electrochemical performance are carried out according to the appendix of GB / T24533-2019, and the rate performance test of the battery is carried out, so that the battery is cycled 10 times at different current densities.

[0078] In this article, raw material A uses ethylene tar, and raw material B uses catalytic oil slurry. The specific properties are shown in Table 1.

[0079] Example 1

[0080] Example 1 uses Figure 1The production process shown, in which the material stream G returns to the pretreatment unit for reaction, and the material stream H returns to the reaction unit B for reaction. The catalyst used in the pretreatment unit is anhydrous aluminum chloride, and the catalyst dosage is 3 wt% of the raw material. The reaction is carried out in the presence of nitrogen. The heat treatment conditions in the pretreatment unit are as follows: the heat treatment temperature is 150 °C, the heat treatment pressure is 5.0 MPa, and the residence time is 4 h. The 95% distillation temperature of the material stream A is 500 °C. The auxiliary agent is tetralin, and the dosage of the auxiliary agent is 10 wt% of the material stream A. The operating conditions of the reaction unit A are as follows: the reaction temperature is 450 °C, the reaction pressure is 2 MPa, and the residence time is 5 h. The obtained material stream C enters the reaction unit B and continues to react under nitrogen purging. The reaction conditions of the reaction unit B are as follows: the reaction temperature is 440 °C, the reaction pressure is 0.5 MPa, and the residence time is 20 h. The generated mesophase pitch enters the subsequent spinning unit, and carbon fiber can be obtained through spinning, pre-oxidation, carbonization, and graphitization treatments. The generated material stream D enters the coking unit to produce petroleum coke for the negative electrode material. The heating furnace adopts variable temperature control, and the variable temperature range is 470 - 500 °C. Feeding starts at 470 °C and rises to 500 °C in 8 h, and constant temperature feeding is carried out for 16 h. The catalytic slurry enters the reaction unit C and reacts in the presence of a nitrogen atmosphere. The reaction conditions of the reaction unit C are as follows: the reaction pressure is 3 MPa, the reaction temperature is 400 °C, and the reaction time is 10 h; then the material stream B is introduced into the reaction unit C to be mixed with the reaction product of the catalytic slurry for heat treatment. The mass ratio of the material stream B to the reaction product of the catalytic slurry is 10:100. At this time, the reaction conditions of the reaction unit C are as follows: carried out in the presence of a nitrogen atmosphere, the reaction pressure is 0.5 MPa, the reaction temperature is 420 °C, and the reaction time is 12 h. After the pitch containing mesophase spheres obtained from the reaction unit C is cooled to room temperature (25 °C), it is added to diesel, and hot filtration is carried out at 250 °C to concentrate the mesophase spheres. Then, it is extracted with quinoline solvent until the solvent in the extractor is colorless and transparent, washed repeatedly with acetone 3 times, and dried at 120 °C for 20 h to obtain mesophase carbon microspheres. The cutting point temperature of the material streams G and H obtained by separating the material streams E and F is 240 °C, the cutting point temperature of the material streams H and I is 420 °C. The material stream G returns to the pretreatment unit to continue the reaction, the material stream H returns to the reaction unit B to continue the reaction together with the material stream C, and the material stream I enters the coking unit to react together with the material stream D. The reaction results are shown in Tables 2, 3, 4, and 5.

[0081] Example 2

[0082] It is basically the same as Example 1. The differences are as follows: the conditions of the pretreatment unit are that the catalyst dosage is 2 wt% of the raw materials, and it is carried out under nitrogen protection. The reaction conditions of the pretreatment unit are: the reaction temperature is 220 °C, the reaction pressure is 3.0 MPa, and the residence time is 0.5 h; the conditions of reaction unit A are that the co - agent is decalin, and the co - agent dosage is 20 wt% of stream A. The conditions of reaction unit A are: the reaction temperature is 420 °C, the reaction pressure is 3 MPa, and the residence time is 12 h; the conditions of reaction unit B are: the reaction temperature is 420 °C, the reaction pressure is 0.5 MPa, and the residence time is 24 h. The heating furnace of the coking unit adopts variable - temperature control, and the variable - temperature range is 470 - 500 °C. Feeding starts at 470 °C, it rises to 485 °C in 4 h, feeds at a constant temperature for 8 h, rises to 500 °C in 1 h, and feeds at a constant temperature for 11 h. The catalytic slurry is not heat - treated separately and reacts with stream B in reaction unit C together according to the mass ratio of 20:100. The conditions of reaction unit C are: nitrogen atmosphere, the reaction pressure is 0.5 MPa, the reaction temperature is 450 °C, and the reaction time is 8 h. Stream G does not return to the pretreatment unit and directly exits the device, stream H returns to reaction unit B for continuous reaction, and stream I enters the coking unit for reaction. The reaction results are shown in Tables 2, 3, 4, and 5.

[0083] Example 3

[0084] Example 3 adopts Figure 1 the production process shown, which is basically the same as Example 2. The differences are as follows: the 95% distillation temperature of stream A obtained in separation unit A is 460 °C. The conditions of reaction unit A are: the co - agent dosage is 30 wt% of stream A. The conditions of reaction unit A are: the reaction temperature is 380 °C, the reaction pressure is 2 MPa, and the residence time is 20 h; the conditions of reaction unit B are: the reaction temperature is 420 °C, the reaction pressure is 1000 Pa (absolute pressure), and the residence time is 6 h; the heating furnace of the coking unit adopts variable - temperature control, and the variable - temperature range is 450 - 500 °C. Feeding starts at 450 °C, it rises to 485 °C in 5 h, feeds at a constant temperature for 8 h, rises to 500 °C in 1 h, and feeds at a constant temperature for 10 h. Stream G separated by separation unit B does not return to the pretreatment unit and directly exits the device, stream H returns to reaction unit B for continuous reaction, and stream I enters the coking unit for reaction. The reaction results are shown in Tables 2, 3, 4, and 5.

[0085] Comparative Example 1

[0086] The difference between Comparative Example 1 and Example 1 is that: in Comparative Example 1, there is no pretreatment unit and separation unit A. The ethylene tar directly enters reaction units A and B. The stream D generated in reaction unit B enters the coking unit to produce petroleum coke for negative electrode materials. The heating furnace adopts constant - temperature control, and feeds at a constant temperature of 500 °C for 24 h; reaction unit C uses only the catalytic slurry as the raw material, and other conditions are basically the same as those in Example 1.

[0087] Comparative Example 2

[0088] The difference between Comparative Example 2 and Example 2 is as follows: in the reaction unit A of Comparative Example 2, there is no additive; the mass ratio of raw material B to stream B in Comparative Example 2 is 15:100; the stream I obtained from the separation unit B does not enter the coking unit, and other conditions are basically the same as those in Example 2.

[0089] For the mesophase pitch obtained from the above examples and comparative examples, its softening point, mesophase pitch content, and spinnability were tested. The carbon fiber obtained by spinning, pre-oxidation, carbonization, and graphitization of the mesophase pitch was tested for its tensile strength, and the results are shown in Table 2; the texture of the mesophase pitch was photographed by a polarized light microscope and quantitatively analyzed using statistical analysis software, and the texture and distribution results are shown in Table 3; the electrochemical performance of the special coke for the negative electrode material after being made into a half-cell is shown in Table 4, and the particle size distribution results of the obtained mesophase carbon microspheres are shown in Table 5.

[0090] Table 1 Raw Material Properties

[0091] Item Ethylene tar Catalytic slurry oil Ash, wt% 0.017 0.016 Sulfur, wt% 0.12 0.42 Distillation range distribution / °C 5％ 249.0 341.8 95％ 702.3 632.4 Four-component, wt% Saturates 2.14 21.28 Aromatics 83.19 75.39 Resin 13.65 3.19 Asphaltenes 1.02 0.14

[0092] Table 2 Properties of Mesophase Pitch and Carbon Fiber

[0093]

[0094] Table 3 Texture and Distribution of Mesophase Pitch

[0095]

[0096] Table 4 Electrochemical Properties of the Negative Electrode Coke after Being Made into a Half-Cell

[0097]

[0098]

[0099] Table 5 Particle Size Distribution of Mesophase Carbon Microspheres

[0100]

Claims

1. A production process for negative electrode coke and mesophase pitch, the production process comprising the following steps: (1) Treat raw material A under heat treatment conditions, and after separation of the resulting liquid stream, obtain stream A and stream B; (2) Under contact conditions, stream A reacts with an auxiliary agent to obtain stream C; the auxiliary agent is a compound containing at least one aromatic ring; (3) The stream C obtained in step (2) further reacts in the presence of a carrier gas to obtain mesophase pitch and stream D; (4) Stream D enters the coking unit, and after the coking reaction is completed, negative electrode coke and stream E are obtained; (5) Treat raw material B under heat treatment conditions to obtain pitch containing mesophase spheres and stream F; (6) Stream E and stream F enter the separation unit, and after separation, gas, stream G, stream H, and stream I are obtained.

2. The production process according to claim 1, characterized in that: The stream I obtained in step (6) enters the coking unit and is mixed with stream D for coking reaction.

3. The production process according to claim 1, characterized in that: The stream H obtained in step (6) returns and is mixed with stream C for further treatment.

4. The production process according to claim 1, characterized in that: The raw material A in step (1) is selected from one or more of ethylene tar, butadiene tar, and high-temperature coal tar, preferably ethylene tar.

5. The production process according to claim 1, characterized in that: The heat treatment conditions in step (1) are as follows: the heat treatment pressure is 0.01 - 10 MPa, preferably the heat treatment pressure is 0.5 - 5 MPa; the heat treatment temperature is 120 - 240 °C, preferably the heat treatment temperature is 130 - 220 °C; the residence time is 0.1 - 12 h, preferably the residence time is 0.5 - 6 h.

6. The production process according to claim 1, characterized in that: The heat treatment in step (1) is carried out under the protection of an inert atmosphere, and the inert atmosphere is nitrogen and / or inert gas, preferably nitrogen.

7. The production process according to claim 1, characterized in that: The 95% distillation temperature of the stream A in step (1) is 460 - 540 °C, preferably 460 - 500 °C.

8. The production process according to claim 1, characterized in that: The heat treatment in step (1) uses or does not use a catalyst, preferably uses a catalyst; the catalyst is anhydrous aluminum chloride, and the addition amount of the catalyst is 1 wt% - 10 wt% of the weight of raw material A, preferably 2 wt% - 5 wt%.

9. The production process according to claim 1, characterized in that: The auxiliary agent in step (2) is selected from one or more of methylnaphthalene, xylene, pyromellitene, tetrahydronaphthalene, decahydronaphthalene, anthracene, and dihydroanthracene, preferably tetrahydronaphthalene; the weight ratio of the auxiliary agent to stream A is 1:100 - 50:100, preferably 10:100 - 30:

100.

10. The production process according to claim 1, characterized in that: The reaction conditions in step (2) are as follows: the reaction temperature is 360 - 500 °C, preferably 360 - 460 °C; the reaction pressure is from atmospheric pressure to 5 MPa, preferably 0.1 - 3 MPa; the residence time of the material in the reactor is 1 - 20 h, preferably 2 - 10 h.

11. According to the production process described in claim 1, it is characterized in that: The reaction conditions in step (3) are as follows: the pressure at the top of the reactor is 20 Pa - 1000 kPa, preferably 20 Pa - 500 kPa; the reaction temperature is 350 - 500 °C, preferably 360 - 460 °C, and the residence time is 6 - 15 h, preferably 6 - 12 h.

12. According to the production process described in claim 1, it is characterized in that: The carrier gas in step (3) is one or more of steam, nitrogen, hydrogen, and inert gas, preferably steam or nitrogen.

13. According to the production process described in claim 1, it is characterized in that: The operating conditions of the coking unit in step (4) are as follows: the heating furnace adopts variable temperature control, and the variable temperature range is 440 - 510 °C, preferably 450 - 500 °C; the coking cycle is 20 - 30 h.

14. According to the production process described in claim 1, it is characterized in that: The heat treatment conditions in step (5) are as follows: the heat treatment pressure is from atmospheric pressure to 5 MPa, preferably from atmospheric pressure to 3 MPa; the heat treatment temperature is 360 - 480 °C, preferably 380 - 450 °C; the heat treatment time is 4 - 60 h, preferably 8 - 48 h.

15. According to the production process described in claim 1, it is characterized in that: The stream B obtained in step (1) is mixed with raw material B for heat treatment.

16. According to the production process described in claim 1, it is characterized in that: The raw material B in step (5) is first subjected to a first-stage heat treatment alone, and then introduced into stream B for a second-stage heat treatment together.

17. According to the production process described in claim 16, it is characterized in that: The first-stage heat treatment conditions are as follows: the first-stage heat treatment pressure is from atmospheric pressure to 5 MPa, preferably 1 - 3 MPa; the first-stage heat treatment temperature is 380 - 480 °C, preferably 400 - 450 °C; the first-stage heat treatment time is 2 - 20 h, preferably 4 - 12 h.

18. According to the production process described in claim 16, it is characterized in that: The second-stage heat treatment conditions are as follows: the second-stage heat treatment pressure is from atmospheric pressure to 1 MPa, preferably from atmospheric pressure to 0.5 MPa; the second-stage heat treatment temperature is 360 - 480 °C, preferably 380 - 450 °C; the second-stage heat treatment time is 2 - 48 h, preferably 4 - 36 h.

19. According to the production process described in claim 1, it is characterized in that: The raw material B in step (5) is one or more of catalytic oil slurry, petroleum asphalt, coal tar pitch, and coal liquefaction residue, preferably catalytic oil slurry.

20. According to the production process described in claim 1, it is characterized in that: The pitch containing mesophase microspheres obtained in step (5) is further subjected to hot filtration, solvent extraction, washing, and drying to obtain mesophase carbon microspheres.

21. According to the production process described in claim 20, it is characterized in that: After the pitch containing mesophase spheres obtained in step (5) is cooled to room temperature, it is added to a dispersion medium for hot filtration to concentrate the mesophase spheres. Then, it is extracted with a solvent until the solvent in the extractor is colorless and transparent, and then washed and dried to obtain mesophase carbon microspheres. The dispersion medium is a hydrocarbon compound, which is one or more of diesel oil, anthracene oil, and naphthalene oil. The hot filtration temperature is 200-250°C, and the filtration time is 1-4 h. The solvent used for solvent extraction is one or more of pyridine, quinoline, and toluene, and quinoline is preferred.

22. According to the production process described in claim 1, it is characterized in that: The cutting temperature of stream G and stream H in step (5) is 230-250°C, preferably 230-240°C; the cutting temperature of stream H and stream I is 410-430°C, preferably 410-420°C.

23. A mesophase pitch obtained by using the production process described in any one of claims 1-22, wherein the softening point of the mesophase pitch is 270-310°C, and the mesophase morphology is a wide-area optical structure.

24. A method for preparing carbon fiber, the content of the preparation method is as follows: The mesophase pitch described in claim 23 is used as a raw material and sent to a spinning machine for spinning. The carbon fiber obtained by spinning can be obtained a carbon fiber product after pre-oxidation, carbonization, and graphitization treatments.

25. A production system for negative electrode coke and mesophase pitch, the production system includes a pretreatment unit, a reaction unit A, a reaction unit B, a reaction unit C, a coking unit, a separation unit A, and a separation unit B; Wherein: The pretreatment unit heat-treats raw material A in the presence of an optional catalyst, and a gas-phase stream and a liquid-phase stream are obtained after the heat treatment; The separation unit A separates the liquid-phase stream from the pretreatment unit to obtain stream A and stream B; The reaction unit A contacts stream A from the separation unit A with an additive for reaction, and stream C is obtained after the reaction is completed; The reaction unit B contacts stream C from the reaction unit A with a carrier gas for reaction in the presence of the carrier gas, and mesophase pitch and stream D are obtained after the reaction is completed; The coking unit feeds stream D from the reaction unit B into the coking unit for coking reaction, and negative electrode coke and stream E are obtained after the reaction is completed; The reaction unit C is used to receive raw material B, and heat-treats raw material B under an inert atmosphere protection condition, and pitch containing mesophase spheres and stream F are obtained after the treatment; The separation unit B is used to receive and separate stream E from the coking unit and stream F from the reaction unit C, and gas, stream G, stream H, and stream I are obtained after the separation.

26. According to the production system described in claim 25, it is characterized in that: The stream I obtained by the separation unit B is connected to the inlet of the coking unit through a pipeline, and stream I is mixed with stream D for coking reaction together.

27. According to the production system described in claim 25, it is characterized in that: The stream H obtained by the separation unit B is connected to the inlet of the reaction unit B through a pipeline, and stream H is mixed with stream C for treatment.

28. According to the production system described in claim 25, it is characterized in that: The material stream G obtained by the separation unit B is connected to the pretreatment unit through a pipeline and mixed with the raw material A for heat treatment.

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