A process and system for co-production of mesophase pitch and mesocarbon microbeads

Abstract

This invention discloses a co-production process and system for mesophase pitch and mesophase carbon microspheres. The process includes the following steps: (1) heat-treating a first raw material, and separating the liquid stream obtained after heat treatment to obtain a first stream and a second stream; (2) contacting the first stream with an additive to carry out a first reaction, and obtaining a third stream after the reaction is completed; (3) carrying out a second reaction in the presence of a carrier gas, and obtaining mesophase pitch and a fourth stream after the reaction is completed; (4) heat-treating a second raw material under an inert atmosphere, and obtaining pitch containing mesophase microspheres and a fifth stream after the reaction; (5) mixing the fifth stream and the fourth stream, and separating to obtain gas, light distillate oil, heavy distillate oil and tail oil. The co-production process and system for mesophase pitch and mesophase carbon microspheres provided by this invention can not only convert ethylene tar into high-value-added spinnable mesophase pitch, but also co-produce mesophase carbon microspheres with uniform particle size distribution.

Description

Technical Field

[0001] This invention belongs to the field of carbon-based materials technology, and in particular relates to a co-production process of mesophase pitch and mesophase carbon microspheres. Background Technology

[0002] Mesophase pitch is a high-quality carbon material precursor made from coal-based, petroleum-based, high-molecular polymers, and other aromatic compounds. It has been widely used in the preparation of various carbon materials such as needle coke, foamed carbon, and high-performance pitch-based carbon fibers. High-performance pitch-based carbon fibers, due to their high strength, high modulus, electrical and thermal conductivity, are widely used in the aerospace field.

[0003] CN112831334A and CN112645304A disclose a method for preparing mesophase pitch and mesophase carbon microspheres. The method uses heavy oil as raw material, extracts it with n-heptane, and then does not mix it with organometallic complexes / biomass materials for shallow catalysis. The heavy components obtained by vacuum distillation of the product are then mixed with free radical auxiliaries to prepare mesophase pitch and mesophase carbon microspheres.

[0004] CN108441244A discloses a method for preparing mesophase carbon microspheres and mesophase pitch. The method involves mixing coal-based pitch with a first solvent to obtain a co-carbonized raw material, which undergoes a first thermal polycondensation reaction. Then, a second solvent is added to mix, dissolve, and separate the solid components. The resulting solid components are then dried to obtain mesophase carbon microspheres. The liquid components are then distilled and subjected to a second thermal polycondensation reaction to obtain mesophase pitch.

[0005] CN104650938A discloses a co-production process for needle coke, mesophase carbon microspheres, and high-quality asphalt. The process involves mixing heavy phase asphalt produced by pretreatment of raw asphalt with the raw asphalt to produce mesophase carbon microspheres, and mixing the high-yield asphalt with refined asphalt obtained by pretreatment of raw asphalt as the raw material for needle coke.

[0006] CN105036116A discloses a method for preparing mesophase pitch or mesophase carbon microspheres from kerosene co-liquefaction residue. The kerosene co-liquefaction residue is subjected to two-stage extraction. The asphalt obtained from the second stage extraction is mixed with heavy oil in a certain proportion and co-carbonized and thermally polycondensed to generate a thermally polycondensed product containing mesophase pitch or mesophase carbon microspheres. After washing and drying, mesophase carbon microspheres are obtained.

[0007] Ethylene tar is mainly composed of polycyclic aromatic hydrocarbons and aromatic olefins, with low levels of heteroatoms such as sulfur and nitrogen. However, its initial coking temperature is low, making it prone to generating coke and other substances that severely affect product quality when used to prepare mesophase pitch. Furthermore, current processes for preparing mesophase carbon microspheres via thermal polycondensation result in microspheres that are prone to agglomeration and have a wide size distribution. Therefore, ensuring the quality of mesophase pitch products and maintaining uniform particle size distribution of carbon microspheres during the thermal polycondensation process are key technical challenges that need to be addressed in this field. Summary of the Invention

[0008] Based on the above analysis, in order to solve the problems existing in the prior art, the core objective of this invention is to provide a co-production process and system for mesophase pitch and mesophase carbon microspheres, which can not only convert ethylene tar into high-value-added spinnable mesophase pitch, but also co-produce mesophase carbon microspheres with uniform particle size distribution.

[0009] This invention provides a process for the co-production of mesophase pitch and mesophase carbon microspheres, the process comprising the following steps:

[0010] (1) The first raw material is heat-treated, and the liquid phase stream obtained after heat treatment is separated to obtain the first stream and the second stream.

[0011] (2) The first feed stream comes into contact with the additive to carry out the first reaction, and the third feed stream is obtained after the reaction is completed;

[0012] (3) Under the condition of carrier gas, the third material stream undergoes the second reaction, and after the reaction is completed, mesophase asphalt and the fourth material stream are obtained;

[0013] (4) The second raw material was heat-treated under an inert atmosphere to obtain asphalt containing mesophase microspheres and the fifth material flow after the reaction;

[0014] (5) The fifth feed stream is mixed with the fourth feed stream and separated to obtain gas, light distillate oil, heavy distillate oil and tail oil.

[0015] Preferably, in the above-mentioned co-production process of mesophase pitch and mesophase carbon microspheres, the first raw material in step (1) is one or more of ethylene tar, butadiene tar, high-temperature coal tar, etc., with ethylene tar being preferred.

[0016] Preferably, in the above-mentioned co-production process of mesophase pitch and mesophase carbon microspheres, the heat treatment in step (1) is generally carried out under the following operating conditions: the heat treatment temperature is 120-240℃, preferably 130-220℃, the heat treatment pressure is 0.01-10MPa, preferably 0.5-5MPa, and the residence time is 0.1-12h, preferably 0.5-6h.

[0017] Preferably, in the above-mentioned co-production process of mesophase pitch and mesophase carbon microspheres, the heat treatment in step (1) is carried out in the presence of an inert atmosphere, which is nitrogen and / or an inert gas, preferably nitrogen; the inert gas can be at least one of helium, neon, argon, krypton and xenon.

[0018] Preferably, in the above-mentioned co-production process of mesophase pitch and mesophase carbon microspheres, the 95% distillation temperature of the first feed stream in step (1) is 460-540°C, preferably 460-500°C.

[0019] Preferably, in the above-mentioned co-production process of mesophase pitch and mesophase carbon microspheres, the method for separating the liquid phase stream obtained after heat treatment in step (1) can be one or more of the following methods: flash distillation, stripping, atmospheric distillation, and vacuum distillation, with vacuum distillation being the preferred method.

[0020] Preferably, in the above-mentioned co-production process of mesophase pitch and mesophase carbon microspheres, a catalyst may or may not be used during the heat treatment process in step (1), but it is preferred to use a catalyst; the catalyst may be anhydrous aluminum chloride, and the amount of catalyst added is 1wt% to 10wt% of the weight of the first raw material, preferably 2wt% to 5wt%.

[0021] Preferably, in the co-production process of the above-mentioned mesophase pitch and mesophase carbon microspheres, the additive in step (2) is a compound containing at least one aromatic ring, selected from one or more of methylnaphthalene, xylene, mesitylene, tetrahydronaphthalene, decahydronaphthalene, anthracene, and dihydroanthracene, preferably tetrahydronaphthalene. Based on weight ratio, the ratio of the additive to the first feed stream is 1:100 to 50:100, preferably 10:100 to 30:100.

[0022] Preferably, in the above-mentioned co-production process of mesophase pitch and mesophase carbon microspheres, the first reaction in step (2) is carried out under the following operating conditions: the reaction temperature is 360-500℃, preferably 360-460℃; the reaction pressure is atmospheric pressure to 5MPa, preferably 0.1-3MPa; and the residence time of the material in the reactor is 1-20h, preferably 2-10h.

[0023] Preferably, in the above-mentioned co-production process of mesophase pitch and mesophase carbon microspheres, the second reaction in step (3) is carried out under the following operating conditions: the pressure at the top of the reactor is 20pa to 1000kpa (absolute pressure), preferably 20pa to 500kpa (absolute pressure); the reaction temperature is 350 to 500℃, preferably 360 to 460℃; and the residence time is 6 to 15h, preferably 6 to 12h.

[0024] Preferably, in the above-mentioned co-production process of mesophase pitch and mesophase carbon microspheres, 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.

[0025] Preferably, in the above-mentioned co-production process of mesophase pitch and mesophase carbon microspheres, the heat treatment conditions in step (4) are as follows: the heat treatment pressure is atmospheric pressure to 5 MPa, preferably atmospheric pressure to 3 MPa; the heat treatment temperature is 360 to 480°C, preferably 380 to 450°C; and the heat treatment time is 4 to 60 h, preferably 8 to 48 h.

[0026] Preferably, in the above-mentioned co-production process of mesophase pitch and mesophase carbon microspheres, the second feed stream obtained in step (1) enters the third reaction unit and is mixed with the second raw material for heat treatment.

[0027] Preferably, in the above-mentioned co-production process of mesophase pitch and mesophase carbon microspheres, the second raw material is first subjected to a first stage heat treatment separately, and then introduced into the second material stream and mixed together for a second stage heat treatment.

[0028] Furthermore, the conditions for the first stage of heat treatment are as follows: the pressure of the first stage of heat treatment is atmospheric pressure to 5 MPa, preferably 1 to 3 MPa; the temperature of the first stage of heat treatment is 380 to 480℃, preferably 400 to 450℃; and the time of the first stage of heat treatment is 2 to 20 hours, preferably 4 to 12 hours.

[0029] Furthermore, the conditions for the second stage of heat treatment are as follows: the pressure of the second stage of heat treatment is atmospheric pressure to 1 MPa, preferably atmospheric pressure to 0.5 MPa; the temperature of the second stage of heat treatment is 360 to 480℃, preferably 380 to 450℃; and the time of the second stage of heat treatment is 2 to 48 hours, preferably 4 to 36 hours.

[0030] Preferably, in the above-mentioned co-production process of mesophase pitch and mesophase carbon microspheres, the second raw material in step (4) can be one or more of the following: catalytic oil slurry, petroleum pitch, coal pitch, coal liquefaction residue, etc.

[0031] Preferably, in the above-mentioned co-production process of mesophase pitch and mesophase carbon microspheres, the pitch containing mesophase microspheres obtained in step (4) is further subjected to hot filtration, solvent extraction, washing and drying to obtain mesophase carbon microspheres.

[0032] Preferably, in the above-mentioned co-production process of mesophase pitch and mesophase carbon microspheres, the pitch containing mesophase microspheres obtained in step (4) is first cooled to room temperature and then added to a dispersion medium for hot filtration treatment to enrich the mesophase microspheres. Then, it is extracted with solvent until the solvent in the extractor is colorless and transparent, and then washed and dried to obtain mesophase carbon microspheres.

[0033] Furthermore, the dispersion medium is a hydrocarbon compound, specifically one or more of diesel oil, anthracene oil, naphthalene oil, etc.; the hot filtration temperature is 200-250℃, and the filtration time is 1-4h.

[0034] Furthermore, the solvent used for solvent extraction is one or more of pyridine, quinoline, and toluene, with quinoline being preferred.

[0035] Further, the washing process involves repeatedly rinsing the solvent-extracted solid material rich in mesophase carbon microspheres with acetone 2-3 times to remove residual organic solvents from the solid material.

[0036] Furthermore, the drying conditions are as follows: drying temperature is 80-120℃, and drying time is 8-24h.

[0037] Preferably, in the above-mentioned co-production process of mesophase pitch and mesophase carbon microspheres, the light distillate oil obtained in step (5) can be returned to be mixed with the first raw material for heat treatment.

[0038] Preferably, in the above-mentioned co-production process of mesophase pitch and mesophase carbon microspheres, the heavy distillate oil obtained in step (5) can be returned to be mixed with the first feed stream and / or the third feed stream for reaction.

[0039] Preferably, in the above-mentioned co-production process of mesophase pitch and mesophase carbon microspheres, the cutting temperature of light distillate oil and heavy distillate oil in step (5) is 230-250℃, preferably 230-240℃; the cutting temperature of heavy distillate oil and tail oil is 410-430℃, preferably 410-420℃.

[0040] A second aspect of the present invention provides an mesophase pitch obtained by the co-production process of the above-mentioned mesophase pitch and mesophase carbon microspheres.

[0041] Furthermore, in the above-mentioned mesophase asphalt, as a preferred embodiment, the softening point of the mesophase asphalt is 270-310°C, and the mesophase morphology exhibits a wide-area optical structure.

[0042] The third aspect of the present invention provides a method for preparing carbon fiber, the method comprising the following steps: firstly, the mesophase pitch obtained by the above-mentioned co-production process of mesophase pitch and mesophase carbon microspheres is fed into a spinning machine for spinning, and the carbon fiber obtained by spinning is subjected to pre-oxidation, carbonization and graphitization treatment to obtain carbon fiber product.

[0043] Furthermore, in the above-mentioned method for preparing carbon fiber, the spinning, pre-oxidation, carbonization, and graphitization processes can all be performed using any of the existing mature processes in the field, and the specific operating conditions can be freely selected and adjusted as needed.

[0044] In the above-mentioned method for preparing carbon fibers, the spinning process can generally be melt spinning, with the spinning temperature being 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 hours; carbonization and graphitization are carried out in an inert atmosphere, with the carbonization temperature being 1100°C and the carbonization time being 1 hour; the graphitization temperature is 2500°C and the graphitization time is 15 minutes.

[0045] A fourth aspect of the present invention provides a co-production system for mesophase pitch and mesophase carbon microspheres, the co-production system comprising a pretreatment unit, a first reaction unit, a second reaction unit, a third reaction unit, a first separation unit, and a second separation unit; wherein:

[0046] The pretreatment unit heat-treats the first raw material in the presence of an optional catalyst, and the heat-treat yields a gaseous stream and a liquid stream.

[0047] The first separation unit separates the liquid phase stream obtained after heat treatment in the pretreatment unit into a first stream and a second stream.

[0048] In the first reaction unit, the first feed stream from the first separation unit comes into contact with the additive to carry out the first reaction, and the third feed stream is obtained after the reaction is completed.

[0049] In the second reaction unit, under the condition of carrier gas, the third material stream from the first reaction unit comes into contact with the carrier gas to carry out the second reaction. After the reaction is completed, mesophase asphalt and the fourth material stream are obtained.

[0050] The third reaction unit is used to receive the second raw material and heat treat the second raw material under an inert atmosphere to obtain asphalt containing mesophase microspheres and the fifth material stream.

[0051] The second separation unit is used to receive and separate the fourth feed stream from the second reaction unit and the fifth feed stream from the third reaction unit, and obtain gas, light distillate oil, heavy distillate oil and tail oil after separation.

[0052] In the above-mentioned co-production system of mesophase pitch and mesophase carbon microspheres, as a preferred embodiment, the light distillate oil obtained from the second separation unit is connected to the pretreatment unit via a pipeline and mixed with the first raw material for heat treatment.

[0053] In the above-mentioned co-production system of mesophase pitch and mesophase carbon microspheres, as a preferred embodiment, the heavy distillate oil obtained from the second separation unit is connected to the first reaction unit and / or the second reaction unit via pipeline, preferably connected to the second reaction unit, and mixed with the third feed stream to carry out the second reaction.

[0054] In the aforementioned co-production system of mesophase pitch and mesophase carbon microspheres, as a preferred embodiment, the first separation unit and the second separation unit employ equipment capable of separating liquid phase materials. This equipment can be at least one of a flash tank, a fractionation tower, etc., with a fractionation tower being preferred. The specific type of fractionation tower can be selected as needed.

[0055] Compared with the prior art, the beneficial effects of the co-production process and system of mesophase pitch and mesophase carbon microspheres provided by the present invention are reflected in one or more of the following aspects:

[0056] 1. The co-production process and system of mesophase pitch and mesophase carbon microspheres provided by this invention achieves the organic combination of two different raw materials (ethylene tar and catalytic slurry as representatives) to simultaneously prepare mesophase pitch and mesophase carbon microspheres through different reaction units. Moreover, the heavy distillate oil obtained by separating the heat-treated oil and gas products of the catalytic slurry system in the third reaction unit and the heat-treated oil and gas products of the ethylene tar system in the second reaction unit is a rich aromatic oil with high thermal stability. Entering the second reaction unit can regulate and reduce the viscosity of the reaction system. At the same time, with the introduction of the heavy distillate oil, some components of the second raw material slurry system can also be introduced. These components can effectively improve the size of the mesophase pitch microstructure, which is conducive to the formation and development of the broad-area mesophase.

[0057] 2. In the co-production process and system of mesophase pitch and mesophase carbon microspheres provided by this invention, the second feed stream obtained from the first separation unit enters the third reaction unit, where it reacts synergistically with the second raw material. The second feed stream acts as both a nucleating agent to promote the formation of mesophase microspheres and a viscosity modifier to reduce the agglomeration between microspheres, resulting in a more uniform particle size distribution of the obtained mesophase microspheres. Recycling the light distillate oil obtained from the second separation unit back to the pretreatment unit can improve the yield of the first feed stream.

[0058] 3. In the co-production process and system of mesophase pitch and mesophase carbon microspheres provided by this invention, ethylene tar first enters the pretreatment unit, preferably under the action of a catalyst to promote the condensation reaction of the easily coking components in the ethylene tar, thereby removing the coking precursors. The liquid phase stream obtained after pretreatment is divided into a first stream and a second stream according to the distillation range. The carbon-carbon double bond content in the first stream is significantly reduced compared to the untreated ethylene tar raw material, and the thermal stability is significantly improved. This avoids the problems of poor product uniformity and poor spinnability caused by directly using ethylene tar as raw material to prepare mesophase pitch. The obtained mesophase pitch has an adjustable softening point between 270-330℃ and a mesophase content of more than 95%. Moreover, the raw materials used in this method are readily available, and the high-quality mesophase pitch product produced has low cost, which is conducive to the large-scale production and sustainable development of high-quality mesophase pitch. It also provides a high-value-added utilization method for ethylene tar that is difficult to process.

[0059] 4. In the co-production process and system of mesophase pitch and mesophase carbon microspheres provided by this invention, the thermal stability of ethylene tar is improved while the rich aromatic components are retained through low-temperature catalytic condensation, separation and other operations. Through the synergistic effect of catalysis, separation, hydrogen supply and heat treatment, high-quality mesophase pitch is prepared from ethylene tar. Attached Figure Description

[0060] Figure 1 This is a schematic diagram of the co-production process and system of mesophase pitch and mesophase carbon microspheres of the present invention. Detailed Implementation

[0061] The method of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but the following embodiments do not constitute a limitation on the method of the present invention.

[0062] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0063] The description of exemplary embodiments is intended to be read in conjunction with the accompanying drawings, which are considered an integral part of the entire written description. In this specification, relative terms such as “lower,” “upper,” “horizontal,” “vertical,” “above,” “below,” “upward,” “downward,” “top,” and “bottom,” and their derivatives (e.g., “horizontally,” “downward,” “upward,” etc.) should be interpreted as referring to the orientation shown in the accompanying drawings as described at the time. These relative terms are for ease of description and do not require the device to be constructed or operated in a particular orientation. Unless otherwise stated, “connection” as used in this invention refers to a relationship in which structures are directly or indirectly fixed or connected to each other via an intermediate structure.

[0064] like Figure 1As shown, this invention provides a co-production process and system for mesophase pitch and mesophase carbon microspheres. The specific process of the co-production is as follows: The first raw material 1 enters the pretreatment unit 2 and is heat-treated in the presence of an optional catalyst. After heat treatment, a gaseous stream 3 and a liquid stream 4 are obtained. The liquid stream 4 enters the first separation unit 5 and is separated to obtain a first stream 6 and a second stream 7. The first stream 6 enters the first reaction unit 8 and undergoes a first reaction with an additive. The third stream 9 obtained after the reaction is completed enters the second reaction unit 10 and undergoes a second reaction in the presence of a carrier gas 12. After the reaction, mesophase pitch 13 and a fourth stream 11 are obtained. The generated mesophase pitch 13 is discharged from the bottom of the second reaction unit 10 and can enter the subsequent spinning unit for further processing. The second raw material 19 and the second feed stream 7 enter the third reaction unit 20 and undergo heat treatment under an inert atmosphere. After the reaction, asphalt 22 containing mesophase microspheres and the fifth feed stream 21 are obtained. The fourth feed stream 11 and the fifth feed stream 21 enter the second separation unit 14, where they are separated to obtain gas 15, light distillate oil 16, heavy distillate oil 17, and tail oil 18. The light distillate oil can be recycled back to the pretreatment unit 2 for processing together with the first raw material 1. The heavy distillate oil can be recycled back to the first reaction unit and / or the second reaction unit for processing, preferably recycled back to the second reaction unit for processing together with the third feed stream. The asphalt 22 containing mesophase microspheres obtained in the third reaction unit is then subjected to hot filtration, solvent washing, and drying to obtain mesophase carbon microspheres.

[0065] In this paper, the specific process conditions for producing carbon fiber from mesophase pitch are as follows: First, the mesophase pitch is fed into a spinning machine for melt spinning, and the spinning temperature is 30-50℃ higher than the softening point; the pre-oxidation medium is air, the pre-oxidation temperature is 250℃, and the pre-oxidation time is 2h; carbonization and graphitization are carried out in an inert atmosphere, with a carbonization temperature of 1100℃ and a carbonization time of 1h; and a graphitization temperature of 2500℃ and a graphitization time of 15min.

[0066] In this paper, the strength of carbon fibers was determined using the standard method of GB / T 31290-2014. The particle size distribution of mesophase carbon microspheres was determined using the standard method of GB / T 19077-2016.

[0067] In this paper, the first feedstock is ethylene tar and the second feedstock is catalytic oil slurry. The specific properties are shown in Table 1.

[0068] Example 1

[0069] Example 1 uses Figure 1The co-production process shown in the diagram involves light distillate oil being returned to the pretreatment unit for further reaction, while heavy distillate oil is returned to the second reaction unit for continued reaction. Anhydrous aluminum chloride is used as the catalyst, at a dosage of 2 wt% of the feedstock, and the reaction is carried out under nitrogen conditions. The pretreatment unit reaction conditions are: reaction temperature 170℃, reaction pressure 5.0 MPa, and residence time 3 h. The 95% distillation temperature of the first feed stream is 500℃. Tetrahydronaphthalene is used as the additive, at a dosage of 10 wt% of the first feed stream. The first reaction unit conditions are: reaction temperature 450℃, reaction pressure 5 MPa, and residence time 6 h. The resulting reactant oil enters the second reaction unit for further reaction under nitrogen purging. The second reaction unit conditions are: reaction temperature 460℃, reaction pressure 0.5 MPa, and residence time 10 h. The generated mesophase pitch enters the subsequent spinning unit, where it undergoes spinning, pre-oxidation, carbonization, and graphitization to obtain carbon fibers. The catalytic slurry was introduced into the third reaction unit under a nitrogen atmosphere. The conditions of the third reaction unit were: reaction pressure 3 MPa, reaction temperature 400℃, and reaction time 10 h. Then, a second feed stream was introduced into the third reaction unit to mix with the catalytic slurry reaction product and heat-treated. The mass ratio of the second feed stream to the catalytic slurry reaction product was 10:100. At this time, the reaction conditions of the third reaction unit were: reaction pressure 0.5 MPa, reaction temperature 420℃, and reaction time 12 h under a nitrogen atmosphere. The asphalt containing mesophase microspheres obtained from the third reaction unit was cooled to room temperature (25℃) and added to diesel fuel. It was then hot-filtered at 250℃ to enrich the mesophase microspheres. Then, it was extracted with quinoline solvent until the solvent in the extractor was colorless and transparent. After washing three times with acetone, it was dried at 120℃ for 20 h to obtain mesophase carbon microspheres. The cut-off temperatures of the light and heavy distillate oils obtained after separation from the fifth and fourth feed streams are 240°C, while the cut-off temperatures of the heavy distillate oil and tail oil are 420°C. The light distillate oil is returned to the pretreatment unit for further reaction, and the heavy distillate oil is returned to the second reaction unit for further reaction. The reaction results are shown in Tables 2 and 3.

[0070] Example 2

[0071] The process is essentially the same as in Example 1. The differences are as follows: the pretreatment unit conditions are: catalyst dosage is 5 wt% of the raw material, protected under nitrogen atmosphere; reaction conditions are: reaction temperature 220°C, reaction pressure 3.0 MPa, residence time 0.5 h; the 95% distillation temperature of the first feed stream is 480°C. The first reaction unit conditions are: the auxiliary agent is decahydronaphthalene, dosage is 20 wt% of the first feed stream; reaction temperature is 420°C, reaction pressure 3 MPa, residence time 12 h; the catalytic slurry is not heat-treated and reacts with the second feed stream at a mass ratio of 20:100 in the third reaction unit; the third reaction unit conditions are: nitrogen atmosphere, reaction pressure 0.5 MPa, reaction temperature 450°C, reaction time 8 h. Additionally, the light distillate oil obtained from the fifth and fourth feed streams is discharged from the unit, while the heavy distillate oil is returned to the second reaction unit for further reaction. The reaction results are shown in Tables 2 and 3.

[0072] Example 3

[0073] Example 3 uses Figure 1 The preparation method shown is basically the same as in Example 2. The difference lies in that the 95% distillation temperature of the first feed stream in the first separation unit is 460°C, the conditions of the first reaction unit are: the amount of auxiliary agent is 30wt% of the first light oil, the reaction temperature is 380°C, the reaction pressure is 2MPa, and the residence time is 15h; the conditions of the second reaction unit are: the reaction temperature is 420°C, the reaction pressure is 1000Pa (absolute pressure), and the residence time is 5h. The reaction results are shown in Tables 2 and 3.

[0074] Comparative Example 1

[0075] The difference between Comparative Example 1 and Example 1 is that Comparative Example 1 does not have a pretreatment unit and a first separation unit, and the third reaction unit uses only catalytic oil slurry as raw material. Other conditions are basically the same as in Example 1.

[0076] Comparative Example 2

[0077] The difference between Comparative Example 2 and Example 2 is that no additives are present in the first reaction unit of Comparative Example 2; the mass ratio of the second raw material to the second feed stream in Comparative Example 2 is 15:100, and other conditions are basically the same as in Example 2.

[0078] The softening point, mesophase pitch content, and spinnability of the mesophase pitch obtained in the above examples and comparative examples were tested. The tensile strength of the carbon fibers obtained by spinning, pre-oxidation, carbonization, and graphitization of the mesophase pitch was tested, and the results are shown in Table 2. The particle size distribution of the obtained mesophase carbon microspheres is shown in Table 3.

[0079] Table 1 Properties of Raw Materials

[0080] project Ethylene tar Catalytic slurry Ash content, wt% 0.018 0.016 Sulfur, wt% 0.12 0.50 Distillation range distribution / °C 5％ 213.2 346.8 95％ 691.8 635.2 Four components, wt% Saturated fraction 0.60 23.38 Aromatic components 83.21 73.29 gelatinous 14.56 3.19 Asphalt 1.63 0.14

[0081] Table 2 Properties of mesophase pitch and carbon fiber

[0082]

[0083] Table 3. Particle size distribution of mesophase carbon microspheres

[0084]

Claims

1. A process for the co-production of mesophase pitch and mesophase carbon microspheres, the process comprising the following steps: (1) The first raw material is subjected to heat treatment. After the heat treatment, the liquid phase stream is separated to obtain the first stream and the second stream. The first raw material is one or more of ethylene tar, butadiene tar, and high-temperature coal tar. The heat treatment is carried out under the following operating conditions: the heat treatment temperature is 120-240℃ and the heat treatment pressure is 0.01-10MPa. The second stream enters the third reaction unit and is mixed with the second raw material for heat treatment. The 95% distillation temperature of the first stream is 460-540℃. (2) The first feed stream comes into contact with the additive to carry out the first reaction, and the third feed stream is obtained after the reaction is completed; the additive is a compound containing at least one aromatic ring; the first reaction is carried out under the following operating conditions: the reaction temperature is 360-500℃, and the reaction pressure is atmospheric pressure to 5MPa; (3) Under the condition of carrier gas, the third feed stream undergoes the second reaction, and after the reaction is completed, mesophase asphalt and the fourth feed stream are obtained; the second reaction is carried out under the following operating conditions: the pressure at the top of the reactor is 20pa~1000kpa, and the reaction temperature is 350~500℃; (4) The second raw material and the second feed stream are heat-treated under an inert atmosphere to obtain asphalt containing mesophase microspheres and the fifth feed stream after the reaction; the second raw material is one or more of catalytic oil slurry, petroleum asphalt, coal tar pitch and coal liquefaction residue; (5) The fifth stream and the fourth stream are mixed and separated to obtain gas, light distillate oil, heavy distillate oil and tail oil; the cutting temperature of light distillate oil and heavy distillate oil is 230-250℃, and the cutting temperature of heavy distillate oil and tail oil is 410-430℃; the heavy distillate oil is returned to be mixed with the first stream and / or the third stream for reaction.

2. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 1, characterized in that: The first raw material in step (1) is ethylene tar.

3. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 1, characterized in that: The heat treatment in step (1) is carried out under the following operating conditions: heat treatment temperature is 130-220℃, heat treatment pressure is 0.5-5MPa, and residence time is 0.1-12h.

4. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 3, characterized in that: The stay duration is 0.5 to 6 hours.

5. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 1, characterized in that: The heat treatment in step (1) is carried out in the presence of an inert atmosphere, which is nitrogen and / or an inert gas.

6. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 1, characterized in that: The heat treatment in step (1) is carried out in the presence of an inert atmosphere, which is nitrogen.

7. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 1, characterized in that: The 95% distillation temperature of the first feed stream in step (1) is 460-500℃.

8. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 1, characterized in that: In the heat treatment process of step (1), a catalyst may or may not be used as needed. The catalyst is anhydrous aluminum chloride, and the amount of catalyst added is 1 wt% to 10 wt% of the weight of the first raw material.

9. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 1, characterized in that: A catalyst is used in the heat treatment process in step (1); the catalyst is anhydrous aluminum chloride, and the amount of catalyst added is 2wt% to 5wt% of the weight of the first raw material.

10. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 1, characterized in that: The additives in step (2) are selected from one or more of methylnaphthalene, xylene, mesitylene, tetrahydronaphthalene, decahydronaphthalene, anthracene, and dihydroanthracene; the ratio of the additives to the first feed stream is 1:100 to 50:100 based on the weight ratio.

11. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 1, characterized in that: The additive in step (2) is tetrahydronaphthalene; the ratio of the additive to the first material flow is 10:100 to 30:100 based on the weight ratio.

12. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 1, characterized in that: The first reaction in step (2) is carried out under the following operating conditions: the reaction temperature is 360-460℃, the reaction pressure is 0.1-3MPa, and the residence time of the material in the reactor is 1-20h.

13. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 12, characterized in that: The residence time of the material in the reactor is 2 to 10 hours.

14. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 1, characterized in that: The second reaction in step (3) is carried out under the following operating conditions: the pressure at the top of the reactor is 20pa to 500kpa, the reaction temperature is 360 to 460℃, and the residence time is 6 to 15h.

15. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 14, characterized in that: The stay is 6 to 12 hours.

16. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 1, characterized in that: The carrier gas in step (3) is one or more of water vapor, nitrogen, hydrogen, and inert gas.

17. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 1, characterized in that: The carrier gas in step (3) is water vapor or nitrogen.

18. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 1, characterized in that: The heat treatment conditions in step (4) are as follows: heat treatment pressure is atmospheric pressure to 5 MPa, heat treatment temperature is 360 to 480 °C, and heat treatment time is 4 to 60 h.

19. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 1, characterized in that: The heat treatment conditions in step (4) are as follows: heat treatment pressure is atmospheric pressure to 3MPa, heat treatment temperature is 380 to 450℃, and heat treatment time is 8 to 48h.

20. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 1, characterized in that: The second raw material is first subjected to the first stage of heat treatment separately, and then introduced into the second material flow to be mixed together for the second stage of heat treatment.

21. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 20, characterized in that: The conditions for the first stage of heat treatment are as follows: the pressure for the first stage of heat treatment is atmospheric pressure to 5 MPa, the temperature for the first stage of heat treatment is 380 to 480℃, and the time for the first stage of heat treatment is 2 to 20 hours.

22. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 20, characterized in that: The conditions for the first stage of heat treatment are as follows: the pressure for the first stage of heat treatment is 1-3 MPa, the temperature for the first stage of heat treatment is 400-450℃, and the time for the first stage of heat treatment is 4-12 h.

23. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 20, characterized in that: The conditions for the second stage of heat treatment are as follows: the pressure for the second stage of heat treatment is atmospheric pressure to 1 MPa, the temperature for the second stage of heat treatment is 360 to 480℃, and the time for the second stage of heat treatment is 2 to 48 hours.

24. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 20, characterized in that: The conditions for the second stage of heat treatment are as follows: the pressure for the second stage of heat treatment is atmospheric pressure to 0.5 MPa, the temperature for the second stage of heat treatment is 380 to 450℃, and the time for the second stage of heat treatment is 4 to 36 hours.

25. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 1, characterized in that: The asphalt containing mesophase microspheres obtained in step (4) is further subjected to hot filtration, solvent extraction, washing and drying to obtain mesophase carbon microspheres.

26. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 1, characterized in that: The asphalt containing mesophase microspheres obtained in step (4) is first cooled to room temperature and then added to a dispersion medium for hot filtration to enrich the mesophase microspheres. Then, it is extracted with solvent until the solvent is colorless and transparent. After washing and drying, mesophase carbon microspheres are obtained.

27. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 26, characterized in that: The dispersion medium is a hydrocarbon compound, which is selected from one or more of diesel oil, anthracene oil, and naphthalene oil; the hot filtration temperature is 200-250℃, and the filtration time is 1-4h.

28. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 26, characterized in that: The solvent used for solvent extraction is one or more of pyridine, quinoline, and toluene.

29. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 26, characterized in that: The solvent used for solvent extraction was quinoline.

30. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 1, characterized in that: The light distillate oil obtained in step (5) is returned to be mixed with the first feedstock for heat treatment.

31. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 1, characterized in that: In step (5), the cutting temperature for light distillate oil and heavy distillate oil is 230-240℃, and the cutting temperature for heavy distillate oil and tail oil is 410-420℃.

32. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 1, characterized in that: The softening point of mesophase pitch is 270–310℃, and the mesophase morphology exhibits a wide-area optical structure.

33. The co-production process of mesophase pitch and mesophase carbon microspheres according to claim 1, characterized in that: The mesophase pitch obtained in step (3) is sent to a spinning machine for spinning. The carbon fibers obtained by spinning are pre-oxidized, carbonized and graphitized to obtain carbon fiber products.

34. A co-production system for implementing the co-production process of mesophase pitch and mesophase carbon microspheres as described in any one of claims 1-33, the co-production system comprising a pretreatment unit, a first reaction unit, a second reaction unit, a third reaction unit, a first separation unit, and a second separation unit; wherein: The pretreatment unit heat-treats the first raw material in the presence of an optional catalyst, and the heat-treat yields a gaseous stream and a liquid stream. The first separation unit separates the liquid phase stream obtained after heat treatment in the pretreatment unit into a first stream and a second stream. In the first reaction unit, the first feed stream from the first separation unit comes into contact with the additive to carry out the first reaction, and the third feed stream is obtained after the reaction is completed. In the second reaction unit, under the condition of carrier gas, the third material stream from the first reaction unit comes into contact with the carrier gas to carry out the second reaction. After the reaction is completed, mesophase asphalt and the fourth material stream are obtained. The third reaction unit is used to receive the second raw material and heat treat the second raw material under an inert atmosphere to obtain asphalt containing mesophase microspheres and the fifth material stream. The second separation unit is used to receive and separate the fourth feed stream from the second reaction unit and the fifth feed stream from the third reaction unit, and obtain gas, light distillate oil, heavy distillate oil and tail oil after separation; the heavy distillate oil is connected to the first reaction unit and / or the second reaction unit via pipeline.

35. The cogeneration system according to claim 34, characterized in that: The light distillate oil obtained from the second separation unit is connected to the pretreatment unit via pipeline and mixed with the first raw material for heat treatment.

36. The cogeneration system according to claim 34, characterized in that: The heavy distillate oil obtained from the second separation unit is connected to the second reaction unit via pipeline and mixed with the third feed stream to carry out the second reaction.

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