Process and system for co-production of binder pitch and mesophase pitch

Abstract

The invention provides a process and system for co-production of binder pitch and mesophase pitch, and the process comprises the following steps: filtering a first aromatic hydrocarbon raw material to obtain an aromatic hydrocarbon raw material 1 *, and mixing the aromatic hydrocarbon raw material 1 * and a second aromatic hydrocarbon raw material to obtain mixed aromatic hydrocarbon oil; heating the mixed aromatic hydrocarbon oil, and distilling the mixed aromatic hydrocarbon oil to obtain an aromatic hydrocarbon base component; the preparation method comprises the following steps: heating an aromatic hydrocarbon base component and cross-linking gas, and carrying out a cross-linking reaction to obtain binder asphalt; the method comprises the following steps: heating the binder pitch and stripping gas, and performing variable-pressure pyrolysis to obtain intermediate-phase binder pitch; the heated mesophase binder pitch is subjected to a deep reaction, and the spinning-grade mesophase pitch is obtained. The raw materials from different sources are adopted, the binder pitch, the mesophase binder pitch and the spinning-grade mesophase pitch products which are excellent in performance and stable in quality can be prepared at the same time, and the purposes that products obtained through the same system are diversified, and the product structures can be flexibly adjusted can be achieved.

Description

Technical Field

[0001] This invention relates to a process and system for co-producing binder bitumen and mesophase bitumen, belonging to the field of carbon materials technology. Background Technology

[0002] Graphite electrodes, isostatic graphite, and various coarse and fine-structure graphite products all require pitch with low impurity content, sufficient carbon content, and suitable fluidity and molecular weight distribution as impregnating agents and binders. Generally, coal tar pitch and heavy petroleum oil are used as raw materials, and the inorganic and organic impurities are removed, and the degree of polymerization of aromatic molecules and the content of light components are controlled to obtain the pitch used as an impregnating agent and binder. The preparation of artificial graphite materials and special carbons also requires purified pitch with very low impurity content, especially pitch with a softening point above 150℃, to achieve high yields, structural strength, and electrochemical performance in subsequent carbonization and graphitization processes. High-performance pitch-based carbon fibers must be prepared using high-quality mesophase pitch as raw material. The mesophase content, aggregate morphology, molecular weight distribution, rheological properties, and impurity content in the pitch must all be controlled at very high levels and be highly stable. Although many research institutions and laboratories have conducted extensive work, it is still currently at the laboratory and pilot-scale levels. General-purpose pitch-based carbon fiber uses high-softening-point homopolymer pitch as raw material. This pitch can be formulated from coal-based or oil-based heavy oil. Unlike the regular arrangement of layered polycyclic aromatic hydrocarbon macromolecules in mesophase pitch, the polycyclic aromatic hydrocarbon molecules in homopolymer pitch retain more alkyl side chains or have poor planarity of the aromatic ring system. Therefore, the reaction processes and preparation technologies of mesophase pitch and homopolymer pitch differ significantly, and existing research and production facilities cannot simultaneously address both. Given the common requirements of various impregnating agent pitches, binder pitches, mesophase pitches, and homopolymer pitches for raw materials, the reaction process all involves dehydrogenation polymerization between aromatic molecules to increase molecular weight and size, while simultaneously requiring the removal of a certain amount of light components from intermediate products. Therefore, in principle, it is possible to design process technologies that meet the needs of multiple products, achieving co-production of multiple products, reducing production costs, and thus enabling the large-scale utilization of these currently high-priced products.

[0003] CN114410331A uses aromatic-rich heavy oil as feedstock. Preheated fresh feedstock is mixed with nitrogen and introduced from the top of a variable-temperature, variable-diameter tubular reactor, passing rapidly through the reactor to obtain an asphalt-like intermediate product with a softening point of 40-160℃. This product then enters a hot low-temperature separator, where nitrogen and some light components are separated from the top. The bottom product enters a scraped-film evaporator to remove and recover the light components, while the heavy components obtained at the bottom of the evaporator enter a mesophase storage tank, thus yielding high-quality spinnable mesophase asphalt. However, in this prior art, the asphalt-like intermediate product obtained from feedstock entering from the top of the reactor is prone to contain large-molecular-weight condensation polymers, affecting the optimal molecular weight distribution of the mesophase asphalt. When the degree of reaction in the tubular reactor is low, the product yield obtained through scraped-film evaporation is low.

[0004] CN115161054A describes a process where ethylene tar is distilled in two stages to obtain heavy components. These heavy components are then subjected to thermal polymerization in a two-stage reactor, during which the pH and sulfur content are adjusted. Short-path molecular distillation is then performed, followed by filtration and granulation to obtain high softening point asphalt. However, this existing technology uses ammonium phosphate in the reaction process, which is difficult to disperse in the oil-based molecular system, thus affecting the uniformity of the reaction products and increasing raw material costs.

[0005] CN113621397A first adds coumarone-indene resin to ethylene tar or petroleum-based pitch to obtain a formulation solution. Then, the formulation solution is mixed with coal tar pitch with a softening point of 30-90℃ to obtain a mixed pitch. The mixed pitch is then oxidized at 320-340℃ to obtain environmentally friendly high-softening-point pitch. However, this prior art uses a formulation solution with significantly different thermal reactivity of aromatic molecules from different sources, increasing the difficulty of reaction control. Furthermore, it cannot be used for the design and production of multiple product solutions.

[0006] CN114479895A uses catalytic or thermal cracked coal tar, FCC slurry clarified oil, reduced-pressure fourth fraction, deasphalted naphthenic vacuum residue, de-QI refined coal tar, and anthracene oil as raw materials. It utilizes a centrifugal reaction separation device, alternating between vertical and inclined rotation of the reaction sleeve 2-3 times to achieve uniform heating and polycondensation of the raw materials within the sleeve, and enrichment of the mesophase product in the lower part of the sleeve. By coordinating the opening and closing of valves at the bottom of the sleeve and the bottom of the device cavity, and by adjusting the molecular weight of the product using a flash evaporator, mesophase pitch and spinnable isotropic pitch can be obtained separately. However, in this prior art, because the density difference between mesophase pitch (softening point greater than 200℃) and isotropic pitch is small, high-speed centrifugation cannot completely separate these two different types of pitch. This operation is suitable for small-batch laboratory preparation, but industrial-scale production is extremely difficult.

[0007] Analysis of the existing technology information reveals two main problems: first, they all involve the production of a single product; second, they are suitable only for small-batch laboratory preparation, leading to reduced operability and increased equipment limitations when scaling up. Therefore, developing technologies that balance low cost and high quality through reactor design and process flow optimization, based on the properties and market size differences of various asphalt products, is the most effective way to solve these industry problems. Summary of the Invention

[0008] To address the aforementioned shortcomings and deficiencies, the present invention aims to provide a process and system for the co-production of binder bitumen and mesophase bitumen. This invention utilizes raw materials from different sources to simultaneously produce high-performance, stable-quality binder bitumen, mesophase binder bitumen, and spinning-grade mesophase bitumen products.

[0009] To achieve the above objectives, on the one hand, the present invention provides a process for co-producing binder bitumen and mesophase bitumen, wherein the process for co-producing binder bitumen and mesophase bitumen includes:

[0010] Step (a): Filter the first aromatic feedstock to obtain aromatic feedstock 1*, mix aromatic feedstock 1* and the second aromatic feedstock to obtain mixed aromatic oil; heat the mixed aromatic oil and then distill it to obtain the basic aromatic components;

[0011] Step (b): The aromatic base components and crosslinking gas are heated to carry out a crosslinking reaction to obtain the binder asphalt;

[0012] Step (c): The binder bitumen and stripping gas are heated and then subjected to pressure swing pyrolysis to obtain mesophase binder bitumen;

[0013] Step (d): Allow the heated mesophase binder pitch to undergo a deep reaction to obtain spinning-grade mesophase pitch.

[0014] As a specific embodiment of the process described above in this invention, the process further includes step (e): using a first vacuum device to sequentially heat and separate, condense and separate, and cryogenically treat the high-temperature oil and gas generated in step (a), the crosslinking reaction in step (b), and the pressure swing pyrolysis in step (c); and using a second vacuum device to sequentially heat and separate, condense and separate, and cryogenically treat the high-temperature oil and gas generated in step (d) through the deep reaction.

[0015] In one specific embodiment of the process described above in this invention, the first vacuum device includes a first oil-gas buffer tank, a first condenser, a first cryogenic cooler, and a first vacuum unit connected in sequence. During operation, high-temperature oil and gas first enter the first oil-gas buffer tank for heating and separation to separate medium-grade aromatic oil. Then, it passes through the first condenser to separate light oil, and the non-condensable vapor enters the first cryogenic cooler for cooling. In some embodiments of this invention, the condensing medium in the first condenser can be cooling water, and the cooling medium in the second cryogenic cooler is a mixture of water and ethylene glycol.

[0016] In one specific embodiment of the process described above in this invention, the second vacuum device includes a second oil-gas buffer tank, a second condenser, a second cryostat, and a second vacuum unit connected in sequence. During operation, high-temperature oil and gas first enter the second oil-gas buffer tank for heating and separation to separate heavy aromatic oil. Then, the second condenser separates medium aromatic oil, and the non-condensable vapor enters the second cryostat for cooling. In some embodiments of this invention, the condensing medium in the second condenser can be cooling water, and the cooling medium in the second cryostat can be a mixture of water and ethylene glycol.

[0017] As a specific embodiment of the process described above in this invention, the temperatures of the heating separation, the condensation separation and the cryogenic treatment are 190-220℃, 2-10℃ and -40 to -30℃, respectively; the pressure of the first vacuum system is adjustable between 1KPa and 1MPa; and the pressure of the second vacuum device is 1-10Pa.

[0018] As a specific embodiment of the process described above in this invention, when the high-temperature oil and gas generated by distillation in step (a) is sequentially heated, separated by condensation and subjected to cryogenic treatment using a first vacuum device, the pressure of the first vacuum system is adjustable between 20-50 kPa.

[0019] In one specific embodiment of the process described above in this invention, the high-temperature oil and gas generated in step (a) through distillation, the high-temperature oil and gas generated in step (b) through cross-linking reaction, and the high-temperature oil and gas generated in step (c) through pressure swing pyrolysis are sequentially heated and condensed using the first oil and gas buffer tank and the first condenser in the first vacuum device. The density of the medium-quality aromatic oil separated by heating is 0.79-0.82 g / cm³. 3 (At 20℃), the density of the light oil separated by condensation is 0.69-0.73 g / cm³. 3 (20℃).

[0020] In one specific embodiment of the process described above in this invention, the high-temperature oil and gas generated in step (d) are sequentially heated and condensed using the second oil-gas buffer tank and the second condenser in the second vacuum device. The density of the heavy aromatic oil separated by heating is 0.83-0.88 g / cm³. 3 (At 20℃), the density of the medium-quality aromatic oil separated by condensation is 0.79-0.82 g / cm³. 3 (20℃).

[0021] As a specific embodiment of the process described above in this invention, the first aromatic feedstock includes one or a combination of several of the following: catalytic cracking slurry oil or its distillate oil, catalytic cycle oil or its distillate oil, solvent-de-oiled asphalt or its distillate oil, and thermal cracking residue oil or its distillate oil.

[0022] The second aromatic feedstock includes one or a combination of several of the following: ethylene tar or its distillate oil, hydrogenated ethylene tar wax oil or its distillate oil, and deasphalted vacuum residue oil or its distillate oil.

[0023] In the process described above in this invention, the catalytic cracking slurry oil used as the first aromatic feedstock refers to the oil product obtained through a catalytic cracking unit. The feedstock processed by this catalytic cracking unit is heavy distillate oil obtained from processing naphthenic crude oil, or heavy distillate oil obtained from processing paraffinic and / or intermediate-based crude oil. The distillate oil used as the first or second aromatic feedstock refers to a portion (partial component) of the oil obtained through distillation from catalytic cracking slurry oil, catalytic cycle oil, solvent-de-oiled asphalt from residue oil, thermal cracking residue, ethylene tar, hydrogenated wax oil from ethylene tar, and de-asphalted oil from vacuum residue. For example, some catalytic cracking slurries contain lighter components; in actual operation, these lighter components are removed through processing, retaining only the heavier fractions.

[0024] As a specific embodiment of the process described above in this invention, the total aromatic hydrocarbon content in the second aromatic hydrocarbon feedstock is 80-95%, wherein, based on the total weight of the total aromatic hydrocarbons, the contents of tricyclic aromatic hydrocarbons, tetracyclic aromatic hydrocarbons, pentacyclic aromatic hydrocarbons, and aromatic hydrocarbons with more than five rings are 1-5%, 25-35%, 50-60%, and 10-20%, respectively, and it contains components with a distillation range greater than 400°C, wherein the fraction with a distillation range greater than 500°C accounts for 70-90% of the total distillation range;

[0025] The total aromatic hydrocarbon content in the aromatic hydrocarbon feedstock 1* is 60-80%, wherein, based on the total weight of the total aromatic hydrocarbons, the contents of tricyclic aromatic hydrocarbons, tetracyclic aromatic hydrocarbons, pentacyclic aromatic hydrocarbons, and aromatic hydrocarbons with more than five rings are 10-20%, 60-70%, 10-20%, and 5-10%, respectively. It contains components with a distillation range greater than 400°C, wherein the fraction with a distillation range of 500°C or higher accounts for 50-80% of the total distillation range.

[0026] In one specific embodiment of the process described above in this invention, the ash content of the second aromatic raw material is less than 10 ppm, and its density at 20°C is 1.10-1.25 g / cm³. 3 The total aromatic hydrocarbon content is 80-95%, of which, based on the total weight of total aromatic hydrocarbons, the contents of tricyclic aromatic hydrocarbons, tetracyclic aromatic hydrocarbons, pentacyclic aromatic hydrocarbons, and aromatic hydrocarbons with more than five rings are 1-5%, 25-35%, 50-60%, and 10-20%, respectively. It contains components with a distillation range greater than 400℃, of which the fraction above 500℃ accounts for 70-90% of the total distillation range. The sulfur content is 0.05-0.2%, and the nitrogen content is 0.01-0.1%. The ash content, total aromatic hydrocarbon content, sulfur content, and nitrogen content are all calculated based on the total weight of the second aromatic hydrocarbon feedstock.

[0027] The ash content of the aromatic feedstock 1* is less than 10 ppm, and its density at 20°C is 1.01-1.12 g / cm³. 3 The total aromatic hydrocarbon content is 60-80%, of which, based on the total weight of total aromatic hydrocarbons, the contents of tricyclic aromatic hydrocarbons, tetracyclic aromatic hydrocarbons, pentacyclic aromatic hydrocarbons, and aromatic hydrocarbons with more than five rings are 10-20%, 60-70%, 10-20%, and 5-10%, respectively. It contains components with a distillation range greater than 400℃, of which the fraction above 500℃ accounts for 50-80% of the total distillation range. The sulfur content is 0.1-0.3%, and the nitrogen content is 0.05-0.2%. The ash content, total aromatic hydrocarbon content, sulfur content, and nitrogen content are all calculated based on the total weight of 1* of aromatic hydrocarbon raw material.

[0028] In step (a) of the process described above in this invention, the purpose of filtering the first aromatic raw material is to remove solid particles. The filtration process has virtually no effect on parameters such as the ash content, total aromatic content, and content of tricyclic aromatics, tetracyclic aromatics, pentacyclic aromatics, and aromatics with more than five rings in the first aromatic raw material. In other words, it can be considered that the parameters of the first aromatic raw material and the aromatic raw material 1* are basically the same.

[0029] As a specific embodiment of the process described above in this invention, in step (a), aromatic raw material 1* and the second aromatic raw material are mixed in a weight ratio of 10:1-3 to obtain a mixed aromatic oil. The mixing temperature is 100-150℃ and the linear velocity is 0.3-0.5m / s.

[0030] As a specific embodiment of the process described above in this invention, in step (a), the mixing method includes online mixing or stirring mixing, preferably online mixing.

[0031] In one specific embodiment of the process described above in this invention, in step (a), the mixed aromatic oil is heated by a heat source inside the first heat exchanger tubes, such as heat transfer oil.

[0032] In one specific embodiment of the process described above in this invention, in step (a), the mixed aromatic oil is heated to 350-380°C and then distilled.

[0033] As a specific embodiment of the process described above in this invention, in step (a), the distillation is a reduced pressure operation with a pressure of 20-50 kPa. The upper temperature of the distillation apparatus used for distillation is 120-150°C, and the lower temperature is 360-380°C. The lower part yields the basic aromatic components.

[0034] In a specific embodiment of the process described above in this invention, in step (a), the heated mixed aromatic oil enters the distillation unit from the middle for component adjustment and further impurity removal. The distillation unit has 1-5 side-stream outlets and aromatic basic component outlets arranged sequentially from top to bottom on its sidewall. The first side-stream outlet yields light aromatic oil with a density of 0.71-0.78 g / cm³. 3 (20℃) Medium-quality aromatic oil was extracted from the second to the fifth sideline production outlet, with a density of 0.79-0.82 g / cm³. 3 (20℃); High-temperature oil and gas are extracted from the top of the distillation apparatus.

[0035] As a specific embodiment of the process described above in this invention, in step (a), the distillation apparatus may be, for example, a fractionation tower.

[0036] As a specific embodiment of the process described above in this invention, in step (b), the crosslinking gas and the aromatic basic component are mixed at a crosslinking gas flow rate to aromatic basic component weight ratio of 1-5:100 and then heated to 350-410°C, that is, the outlet temperature of the first heating device used for heating is 350-410°C, wherein the crosslinking gas flow rate is in L / min and the aromatic basic component weight is in kg.

[0037] As a specific embodiment of the process described above in this invention, in step (b), the first heating device used for heating can be a tubular heating furnace. In this case, the specific operation steps of the mixing process include injecting crosslinking gas into the furnace tube of the tubular heating furnace and mixing it with the passing aromatic basic components.

[0038] In one specific embodiment of the process described above in this invention, in step (b), the crosslinking gas includes an oxygen-containing gas. In some embodiments of this invention, the crosslinking gas may be, for example, air.

[0039] In step (b), a crosslinking gas is injected. This gas participates in the crosslinking reaction. During the reaction, oxygen molecules in the crosslinking gas crosslink with aromatic molecules under thermal action, thereby more easily increasing the molecular weight of the asphalt. This transforms the petroleum-derived component (i.e., the component with lower carbon content) into a binder asphalt with a higher molecular weight, i.e., a higher coking value. Furthermore, the use of the crosslinking gas can also increase the linear velocity.

[0040] In one specific embodiment of the process described above in this invention, in step (b), the crosslinking reaction is carried out in a first reactor at a temperature of 380-410°C, with a material residence time of 8-10 hours. The pressure is adjusted to 0.8-0.9 MPa for the first 4-5 hours and to 10-30 kPa for the following 4-5 hours. The target pressure in the first reactor can be adjusted by regulating the pressure valve during the crosslinking reaction.

[0041] In step (b) of the process described above in this invention, in addition to the binder asphalt, the crosslinking reaction also generates high-temperature oil and gas, which contains medium-grade aromatic oil and light oil and gas, and can be recovered by the first vacuum device.

[0042] In a specific embodiment of the process described above in this invention, in step (b), the crosslinking reaction is carried out in a first reactor. The aromatic base component enters the first reactor from the top. In the first reactor, the molecular weight of the aromatic base component increases and its distribution is adjusted to generate binder asphalt. The generated binder asphalt is discharged from the outlet located at the bottom of the first reactor. The height and other dimensions of the first reactor can be designed according to the reaction residence time of the material, and the residence time of the material in the first reactor can be controlled by combining the feed rate. The asphalt in the upper part of the first reactor is the material with a shorter reaction time, while the product at the bottom is the asphalt that has reached the reaction time and degree. The upper material has a lower density, while the lower material has a higher density. In order to facilitate the discharge of viscous asphalt, the outlet at the bottom of the first reactor can be designed as a cone (e.g., the taper can be 1:1) to facilitate cone-shaped discharge. After discharge, the material is introduced into a binder asphalt buffer tank, and then transported by a high-temperature pump (high-temperature gear pump) to a second heating device for heating before being sent to the second reactor for the next reaction.

[0043] As a specific embodiment of the process described above in this invention, step (b) further includes cooling the binder asphalt into sheets using a binder asphalt flake machine to obtain cooled binder asphalt sheets. The softening point of the cooled binder asphalt sheets is 105-120℃, the coking value is 55-58%, the content of quinoline insolubles is 2-8%, the content of toluene insolubles is 22-30%, the ash content is 0.001-0.003%, the content of mesophase with a size greater than 10μm is 0%, and the content of mesophase with a size less than 10μm is less than 0.5%. All contents are weight percentages calculated based on the total weight of the cooled binder asphalt sheets.

[0044] As a specific embodiment of the process described above in this invention, in step (c), stripping gas and binder asphalt are mixed at a ratio of stripping gas flow rate to binder asphalt weight of 1-5:100 and then heated to 400-430°C, wherein the unit of stripping gas flow rate is L / min and the unit of binder asphalt weight is kg.

[0045] As a specific embodiment of the process described above in this invention, in step (c), the second heating device used for heating can also be a tubular heating furnace. In this case, the specific operation steps of the mixing process include injecting stripping gas into the furnace tube of the tubular heating furnace and mixing it with the passing binder asphalt.

[0046] As a specific embodiment of the process described above in this invention, in step (c), the stripping gas includes, but is not limited to, nitrogen and / or water vapor.

[0047] The reaction type in step (c) of the process described above in this invention is pressure swing pyrolysis, which involves simultaneous thermal decomposition and thermal polycondensation. This means that during polymerization, some aromatic hydrocarbon side chains break down to generate small molecule hydrocarbons, which are gases at the temperature conditions in step (c). The purpose of thermal polycondensation is to further increase the molecular weight and generate an intermediate phase (a liquid crystal morphology). However, the degree of thermal polycondensation is usually difficult to control. At low temperatures, the intermediate phase cannot be generated, resulting in a lower molecular weight product. At high temperatures, excessively vigorous polycondensation generates coke, which becomes an impurity in the asphalt. Furthermore, because thermal polycondensation and thermal decomposition occur simultaneously, the reaction cannot continue towards thermal polycondensation when the gas and asphalt liquid in the reactor reach gas-liquid equilibrium. To increase the degree of polymerization, the conventional approach in the prior art is to increase the reaction temperature. However, increasing the reaction temperature easily leads to excessively high degrees of thermal polycondensation, resulting in a heterogeneous asphalt material with unstable quality and a low yield of finished products. To address this, the present invention utilizes stripping gas in step (c), which reduces the partial pressure of the gas obtained from thermal decomposition in the reaction system at a relatively low reaction temperature. This allows the thermal polycondensation reaction to proceed to a higher degree, ensuring an increase in the molecular weight of the product and improving the uniformity of the asphalt. Furthermore, using stripping gas in step (c) can also increase the linear velocity of the material flowing through the pipeline, thereby enhancing the stability of the formation process.

[0048] In one specific embodiment of the process described above in this invention, in step (c), the pressure swing pyrolysis is carried out in a second reactor at a temperature of 390-420°C, i.e., the outlet temperature of the second heating device used for heating is 390-420°C. The residence time of the binder asphalt in the second reactor is 4-8 hours, with the pressure adjusted to 3-5 MPa for the first 2-4 hours and 5-20 kPa for the following 2-4 hours. The target pressure in the second reactor can be adjusted by regulating the pressure regulating valve during the pressure swing pyrolysis process.

[0049] In step (c) of the process described above in this invention, in addition to the mesophase binder bitumen, pressure swing pyrolysis also generates high-temperature oil and gas, which contains medium-quality aromatic oil and light gas, and can be recovered by the first vacuum device.

[0050] In a specific embodiment of the process described above in this invention, in step (c), the pressure swing pyrolysis is carried out in a second reactor. Heated binder asphalt enters the second reactor from the middle. In the second reactor, the binder asphalt undergoes a deep reaction / pyrolysis reaction to generate mesophase binder asphalt and high-temperature oil and gas. The pyrolysis reaction includes thermal decomposition and thermal polycondensation. When aromatic molecules react, the aromatic core (center) undergoes thermal polymerization to obtain mesophase binder asphalt, and the side chains of the aromatic core (center side chains) undergo pyrolysis to generate high-temperature oil and gas. The second reactor has an oil and gas outlet at the top and a discharge port at the bottom. The high-temperature oil and gas is discharged through the oil and gas outlet and then recovered by a first vacuum device. The mesophase binder asphalt is discharged from the discharge port. To facilitate the discharge of viscous asphalt, the discharge port at the bottom of the second reactor can also be designed as conical (e.g., the taper can be 1:1) to facilitate conical discharge. After discharge, the material is fed into the mesophase binder asphalt buffer tank, and then transported to the second heat exchanger by a high-temperature pump (high-temperature gear pump). After being heated by the heat source inside the tubes of the second heat exchanger, the material is sent to the third reactor to continue the next reaction.

[0051] As a specific embodiment of the process described above in this invention, in step (c), the pressure swing pyrolysis is carried out under stirring conditions. Accordingly, the second reactor is a heating reactor with a stirring paddle. The stirring paddle can be an anchor frame paddle and / or a ribbon paddle. The stirring paddle and the interior of the second reactor are in direct contact. The stirring speed can be, for example, 50-100 r / min.

[0052] As a specific embodiment of the process described above in this invention, step (c) further includes cooling the mesophase binder asphalt into flakes using a mesophase binder asphalt flake machine and then discharging the cooled mesophase binder asphalt flakes. The cooled mesophase binder asphalt flakes have a softening point of 160-190℃, a coking value of 60-70%, a quinoline insoluble content of 7-10%, a toluene insoluble content of 35-45%, an ash content of 0.002-0.004%, and a mesophase content of 50-60%. The mesophase consists of small spheres with a size of 10-30μm. All contents are calculated as weight percentages based on the total weight of the cooled mesophase binder asphalt flakes.

[0053] In one specific embodiment of the process described above in this invention, in step (d), the temperature of the heated mesophase binder asphalt is 380-410°C.

[0054] As a specific embodiment of the process described above in this invention, in step (d), the mesophase binder asphalt is heated by a heat source in the tubes of the second heat exchanger. The heat source / heat exchange medium includes, but is not limited to, saturated steam, heat transfer oil or molten salt, preferably heat transfer oil, and more preferably, the temperature of the heat transfer oil is 370-390°C.

[0055] In one specific embodiment of the process described above in this invention, in step (d), the mesophase binder pitch is heated and mixed with an inert gas and then subjected to a deep reaction to obtain spinning-grade mesophase pitch. The deep reaction in step (d) involves thermal polymerization while removing volatiles. The purpose is to enhance the exit of unreacted molecules (i.e., molecules that cannot polymerize or have a low degree of polymerization in steps (b) and (c)) from the reactant system at a lower temperature. However, the mesophase binder pitch obtained in step (c) contains mesophase liquid crystals, has a high viscosity, and is more prone to localized coking reactions under heat. Furthermore, due to the high viscosity of the system, the heat of reaction is not easily transferred. Therefore, in step (d), this invention introduces an inert gas as a carrier gas to assist these unreacted molecules in leaving the reactant system, thereby obtaining spinning-grade mesophase pitch with superior quality and stability.

[0056] In addition, in step (d), heating and mixing the mesophase binder pitch with the inert gas together is better than heating the mesophase binder pitch separately first and then mixing the heated mesophase binder pitch with the inert gas, because simultaneous heating of gas and liquid materials will increase the linear velocity of both during heating, reducing the chance of high viscosity materials being overheated and coking due to slow flow and stagnation.

[0057] In some embodiments of the present invention, the inert gas in step (d) includes nitrogen and the like.

[0058] As a specific embodiment of the process described above in this invention, step (d) further includes: discharging the spinning-grade mesophase pitch at a heating temperature of 330-350°C and filtering it through a filter medium during the discharge process. The filter medium is a filter layer with a pore size of 300-400 mesh formed by ceramic particles. Then, the filtered pitch is passed through a magnetic field with a magnetic field strength of 0.5-1T perpendicular to the discharge pipeline. Finally, the pitch is cooled into flakes by a spinning-grade mesophase pitch flake forming machine and discharged to obtain cooled and flake-formed spinning-grade mesophase pitch.

[0059] In one specific embodiment of the process described above in this invention, in step (d), the temperature of the heated mesophase binder asphalt is 380-410°C.

[0060] In one specific embodiment of the process described above in this invention, in step (d), the temperature of the deep reaction is 370-410°C and the material residence time is 4-8 hours.

[0061] In a specific embodiment of the process described above in this invention, in step (d), the deep reaction is carried out in a third reactor. The third reactor has an inlet at its lower part or bottom, an outlet at its upper part, and an oil and gas outlet at its top. The heated mesophase binder pitch enters the third reactor from the inlet at its lower part. After deep reaction and molecular weight adjustment, it forms spinning-grade mesophase pitch and is discharged from the outlet at the upper part of the third reactor through a high-temperature pump. The discharge pipeline is equipped with heat tracing at a temperature of 330-350°C. A filter is installed in the heat tracing area. The filter medium is a filter layer with a pore size of 300-400 mesh formed by ceramic particles. The pitch passing through the filter layer enters an external magnetic strip that generates a magnetic field perpendicular to the discharge pipeline with a magnetic field strength of 0.5-1T. Finally, the pitch is cooled into flakes by a spinning-grade mesophase pitch flake machine and discharged to obtain cooled and flake-shaped spinning-grade mesophase pitch. The high-temperature oil and gas (heavy aromatic oil and oil and gas) discharged from the oil and gas outlet is recovered by a second vacuum device. The softening point of the cooled, sheet-formed spinning-grade mesophase pitch is 275-285℃, the coking value is 72-80%, the content of quinoline insolubles is 35-40%, the content of toluene insolubles is 70-80%, the ash content is 0.003-0.005%, the mesophase content is 100%, and the yield is 35-45% (calculated based on the total weight of the starting aromatic feedstock, i.e., the first aromatic feedstock and the second aromatic feedstock). All contents are weight percentages calculated based on the total weight of the cooled, sheet-formed spinning-grade mesophase pitch.

[0062] In summary, the process provided by this invention, through the design of different properties of aromatic molecules in petroleum heavy oil feedstock, combined with the overall process flow, feeding method, internal structure of the three-stage reactor and adjustment of process parameters, has obtained special pitches (binder pitch, mesophase binder pitch and spinning-grade mesophase pitch) with different microcrystalline structures and polarization structures. Moreover, these special pitches can meet the performance requirements of various mechanical and structural carbon materials.

[0063] On the other hand, the present invention also provides a system for co-producing binder bitumen and mesophase bitumen for implementing the above-described process, wherein the system for co-producing binder bitumen and mesophase bitumen includes:

[0064] The system comprises a first aromatics feed tank, a second aromatics feed tank, an aromatics feed tank 1*, a filtration device, a first heat exchanger, a distillation device, a gas source, a first heating device, a first reactor, a second heating device, a second reactor, a second heat exchanger, and a third reactor.

[0065] The first aromatic feed tank is connected to the inlet of the aromatic feed 1* tank via a pipeline and a filter device. The outlets of the aromatic feed 1* tank and the second aromatic feed tank are connected to the inlet of the distillation unit via a pipeline and a first heat exchanger. The aromatic basic component outlet of the distillation unit is connected to the inlet of the first reactor via a pipeline and a first heating device. The gas source is connected to the first heating device via a pipeline. The binder pitch outlet of the first reactor is connected to the inlet of the second reactor via a pipeline and a second heating device. The mesophase binder pitch outlet of the second reactor is connected to the inlet of the third reactor via a pipeline and a second heat exchanger.

[0066] As a specific embodiment of the system described above in this invention, the system further includes a first vacuum device and a second vacuum device. The high-temperature oil and gas outlets of the distillation device, the first reactor, and the second reactor are respectively connected to the first vacuum device via pipelines. The high-temperature oil and gas outlet of the third reactor is connected to the second vacuum device via a pipeline. The first vacuum device includes a first oil and gas buffer tank, a first condenser, a first cryogenic reactor, and a first vacuum unit connected in sequence via pipelines. The second vacuum device includes a second oil and gas buffer tank, a second condenser, a second cryogenic reactor, and a second vacuum unit connected in sequence via pipelines.

[0067] In one specific embodiment of the system described above, the system further includes a ceramic filter, an external magnetic strip, and a spinning-grade mesophase pitch flake machine. The spinning-grade mesophase pitch outlet of the third reactor is connected to the spinning-grade mesophase pitch flake machine via a pipeline, passing sequentially through the ceramic filter and the external magnetic strip. A heat tracing device is installed in the pipeline between the spinning-grade mesophase pitch outlet of the third reactor and the ceramic filter. In principle, all pipelines through which the pitch flows require heat tracing in the system described above. However, the heat tracing device installed in the pipeline between the spinning-grade mesophase pitch outlet of the third reactor and the ceramic filter is particularly important, and its temperature is higher than that of the heat tracing devices installed in other pipelines.

[0068] As a specific embodiment of the system described above in this invention, the system further includes a binder asphalt buffer tank and a binder asphalt flake machine. The binder asphalt outlet of the first reactor is connected to the inlet of the second reactor via a pipeline through the binder asphalt buffer tank and the second heating device. The binder asphalt buffer tank is also connected to the binder asphalt flake machine via a pipeline.

[0069] As a specific embodiment of the system described above in this invention, the system further includes a mesophase binder asphalt buffer tank and a mesophase binder asphalt flake machine. The mesophase binder asphalt outlet of the second reactor is connected to the inlet of the third reactor via a pipeline through the mesophase binder asphalt buffer tank and the second heat exchanger. The mesophase binder asphalt buffer tank is also connected to the mesophase binder asphalt flake machine via a pipeline.

[0070] In one specific embodiment of the system described above in this invention, the distillation apparatus may be a fractionation tower or the like.

[0071] As a specific embodiment of the system described above in this invention, the first heating device and the second heating device may be heating furnaces, preferably tubular heating furnaces.

[0072] In one specific embodiment of the system described above, the second reactor is further provided with a stirrer / stirring paddle, which is in direct contact with the interior of the second reactor. In some embodiments of the present invention, the stirring paddle may be selected from anchor-frame paddles and / or ribbon paddles, etc.

[0073] In one specific embodiment of the system described above in this invention, the ceramic filter uses a filter layer with a pore size of 300-400 mesh formed by ceramic particles as the filter medium.

[0074] Compared with the prior art, the beneficial technical effects achieved by the present invention include:

[0075] The process for co-producing binder pitch and mesophase pitch provided by this invention uses a mixture of aromatic raw material 1* and a second aromatic raw material as raw materials. First, the raw materials are fractionated or purified to obtain heavy aromatic basic components. Then, a cross-linking reaction is conducted to obtain binder pitch with suitable molecular weight and reasonable component distribution. Next, the binder pitch undergoes a pressure swing pyrolysis reaction to obtain mesophase binder pitch. Further thermal polymerization and removal of light components result in a further pyrolysis reaction to obtain spinning-grade mesophase pitch. The process provided by this invention uses raw materials from different sources and can simultaneously produce high-performance, stable-quality binder pitch, mesophase binder pitch, and spinning-grade mesophase pitch products, achieving the goal of obtaining product diversification and flexible adjustment of product structure within the same system.

[0076] Compared with existing technologies, the entire process makes full use of equipment, minimizes investment, facilitates large-scale continuous production through equipment selection and design, reduces production costs, and ensures stable product quality. It can meet the requirements of different products and industries, such as graphite electrodes, isostatic graphite, lithium battery anodes, and high-performance carbon fibers. Attached Figure Description

[0077] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0078] Figure 1 This is a schematic diagram of the system for co-producing binder bitumen and mesophase bitumen provided in Embodiment 1 of the present invention.

[0079] Explanation of main icon numbers:

[0080] 1. First aromatics feedstock tank; 2. Second aromatics feedstock tank; 3. Aromatics feedstock 1 * Tank; 1-1 and 1-2 are the first and second filters respectively; 1-3, 1-4, 1-5, 1-6, 1-7 and 1-8 are the first to sixth high-temperature pumps respectively; 4, first heat exchanger; 5, fractionation tower; 6, light oil tank; 7, medium oil tank; 8-1, first oil-gas buffer tank; 9-1, first condenser; 10-1, first cryogenic unit; 11-1, first vacuum unit; 8-2, second oil-gas buffer tank; 9-2, second condenser; 10-2, second cryogenic unit; 11-2, second vacuum unit. 12. Air source; 13. First tubular heater; 14. First reactor; 14-1. Binder pitch buffer tank; 14-2. Binder pitch flake machine; 15. Second reactor; 15-1. Agitator; 15-2. Mesophase binder pitch buffer tank; 15-3. Mesophase binder pitch flake machine; 16. Third reactor; 16-1. Ceramic filter; 16-2. External magnetic strip; 16-3. Spinning grade mesophase pitch flake machine; 17. Second tubular heater; 18. Second heat exchanger. Detailed Implementation

[0081] It should be noted that the term "comprising" and any variations thereof in the specification, claims, and accompanying drawings of this invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0082] The "range" disclosed in this invention is given in the form of a lower limit and an upper limit. It can be one or more lower limits and one or more upper limits, respectively. A given range is defined by selecting a lower limit and an upper limit. The selected lower and upper limits define the boundaries of the particular range. All ranges defined in this way are composable, meaning that any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for specific parameters, it is also expected that ranges of 60-110 and 80-120 are also expected. Furthermore, if the listed minimum range values ​​are 1 and 2, and the listed maximum range values ​​are 3, 4, and 5, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5.

[0083] In this invention, unless otherwise specified, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this invention, and "0-5" is simply a shortened representation of these numerical combinations.

[0084] In this invention, unless otherwise specified, all embodiments and preferred embodiments mentioned in this invention can be combined with each other to form new technical solutions.

[0085] In this invention, unless otherwise specified, all technical features and preferred features mentioned in this invention can be combined with each other to form new technical solutions.

[0086] In this invention, unless otherwise specified, all steps mentioned herein may be performed sequentially or randomly, but are preferably performed sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0087] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying tables, drawings, and embodiments. The embodiments described below are some, but not all, embodiments of this invention, and are only used to illustrate the invention, and should not be considered as limiting the scope of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0088] In this invention, the softening points of the binder pitch, mesophase binder pitch, and spinning-grade mesophase pitch were tested according to the standard test method for pitch softening point (Miller's cup method) in ASTM D3461-97 (2012). The ash content was tested according to GB / T 2295-2008, the method for determining ash content in coking solids; the coking value was tested according to GB / T 8727-2008, the method for determining coking value in coal tar pitch products; the toluene-insoluble content was tested according to GB / T 2292-2018, the method for determining toluene-insoluble content in coking products; and the quinoline-insoluble content was tested according to GB / T 2293-1997, the method for testing quinoline-insoluble content in coking solids products. The mesophase content in the binder pitch was tested according to the light reflection microscopy analysis method for determining the mesophase content in coking pitch products in GB / T 38396-2019. The mesophase content in mesophase binder pitch and spinning-grade mesophase pitch was tested according to YB / T 4822-2020, "Determination of the Optical Structure of Mesophase Coke in Coal-Series Needle Coke".

[0089] Example 1

[0090] This embodiment provides a system for co-producing binder bitumen and mesophase bitumen, the structural schematic diagram of which is shown below. Figure 1 As shown, from Figure 1 As can be seen from this, the system includes:

[0091] First aromatic feed tank 1, second aromatic feed tank 2, aromatic feed tank 1* 3, first filter 1-1, second filter 1-2, first heat exchanger 4, fractionation tower 5, gas source 12, first tubular heater 13, first reactor 14, second tubular heater 17, second reactor 15, second heat exchanger 18, third reactor 16, first vacuum device and second vacuum device.

[0092] The first aromatic feedstock tank 1 is connected to the inlet of the aromatic feedstock 1* tank 3 via a pipeline through the first filter 1-1, the second filter 1-2 and the first high-temperature pump 1-3. The outlets of the aromatic feedstock 1* tank 3 and the second aromatic feedstock tank 2 are connected to the inlet of the fractionation tower 5 via a pipeline through the second high-temperature pump 1-4 and the first heat exchanger 4. The inlet of the fractionation tower 5 is located in the middle, and its sidewall is provided with 1-5 side-stream outlets and aromatic basic component outlets from top to bottom. The first side-stream outlet is connected to the light oil tank 6 via a pipeline, and the second to fifth side-stream outlets are respectively connected to the medium oil tank 7 via pipelines. A high-temperature oil and gas outlet is provided at the top of the tower.

[0093] The aromatics base component outlet of fractionation tower 5 is connected via pipeline to the inlet of the first reactor 14 (located at the top of the first reactor 14) through the third high-temperature pump 1-5, the first tubular heater 13, and a gas source 12 is connected via pipeline to the first tubular heater 13. The binder pitch outlet of the first reactor 14 (located at the bottom of the first reactor 14) is connected via pipeline to the inlet of the second reactor 15 (located in the middle of the second reactor 15) through the binder pitch buffer tank 14-1, the fourth high-temperature pump 1-6, and the second tubular heater 17. The binder pitch buffer tank 14-1 is also connected via pipeline to the binder pitch flake machine 14-2. The mesophase binder pitch outlet of the second reactor 15 (located at the bottom of the second reactor 15) is connected via pipeline to the inlet of the third reactor 16 (located at the middle of the second reactor 15) through the mesophase binder pitch buffer tank 15-2, the fifth high-temperature pump 1-7, and the second heat exchanger 18. The mesophase binder pitch buffer tank 15-2 is connected to the lower part of the third reactor 16. It is also connected to the mesophase binder pitch flake machine 15-3 via a pipeline. The spinning-grade mesophase pitch outlet of the third reactor 16 (located at the upper part of the third reactor 16) is connected to the spinning-grade mesophase pitch flake machine 16-3 via a pipeline, sequentially passing through the sixth high-temperature pump 1-8, the ceramic filter 16-1, and the external magnetic strip 16-2. A heating device is installed in the pipeline between the spinning-grade mesophase pitch outlet of the third reactor 16 and the ceramic filter 16-1. The second reactor 15 is also equipped with a stirring paddle 15-1, which is in direct contact with the interior of the second reactor 15. The stirring paddle 15-1 can be selected from anchor-frame paddles and / or ribbon paddles, etc. The ceramic filter 16-1 uses a filter layer with a pore size of 300-400 mesh formed by ceramic particles as the filter medium.

[0094] The first vacuum device includes a first oil-gas buffer tank 8-1, a first condenser 9-1, a first cryogenic reactor 10-1, and a first vacuum unit 11-1 connected in sequence by pipelines; the second vacuum device includes a second oil-gas buffer tank 8-2, a second condenser 9-2, a second cryogenic reactor 10-2, and a second vacuum unit 11-2 connected in sequence by pipelines. The high-temperature oil-gas outlets of the fractionation tower 5, the first reactor 14, and the second reactor 15 (located at the top of the fractionation tower 5, the first reactor 14, and the second reactor 15, respectively) are connected to the first oil-gas buffer tank 8-1 in the first vacuum device by pipelines. The high-temperature oil-gas outlet of the third reactor 16 (located at the top of the third reactor 16) is connected to the second oil-gas buffer tank 8-2 in the second vacuum device by pipelines.

[0095] Example 2

[0096] This embodiment provides a process for co-producing binder bitumen and mesophase bitumen, which is implemented using the system for co-producing binder bitumen and mesophase bitumen provided in Example 1. The process includes the following specific steps:

[0097] Catalytic cracking slurry was selected as the first aromatic feedstock, and the heavy distillate of ethylene tar was selected as the second aromatic feedstock. The first aromatic feedstock was filtered through a first filter and a second filter to remove solid particles, yielding aromatic feedstock 1*. Aromatic feedstock 1* had an ash content of 6 ppm and a density of 1.02 g / cm³ (20℃). 3 The total aromatic hydrocarbon content is 62%, of which, by weight, the percentages of tricyclic aromatic hydrocarbons, tetracyclic aromatic hydrocarbons, pentacyclic aromatic hydrocarbons, and aromatic hydrocarbons with more than five rings are 17%, 61%, 13%, and 9%, respectively. It contains fractions with a distillation range greater than 500°C, which account for 52% of the total distillation range. The sulfur content is 0.24%, and the nitrogen content is 0.1%.

[0098] The ash content of aromatic feedstock 2 is 10 ppm, and its density is 1.11 g / cm³ (20℃). 3 The total aromatic hydrocarbon content is 90%, of which, by weight, the percentages of tricyclic aromatic hydrocarbons, tetracyclic aromatic hydrocarbons, pentacyclic aromatic hydrocarbons, and aromatic hydrocarbons with more than five rings are 5%, 32%, 51%, and 12%, respectively. It contains fractions with a distillation range greater than 500°C, which account for 73% of the total distillation range. The sulfur content is 0.2% and the nitrogen content is 0.1%.

[0099] Aromatic raw material 1 *The second aromatic feedstock is mixed online at a weight ratio of 10:1 at a temperature of 100℃ and a linear velocity of 0.5 m / s, yielding a mixed aromatic oil. This mixed aromatic oil is then passed through a first heat exchanger, where it undergoes heat exchange via a heat transfer oil. The mixed aromatic oil, heated to 380℃, enters a fractionation tower for component adjustment and further impurity removal. The fractionation tower operates at a pressure of 49 kPa, with an upper temperature of 140℃ and a lower temperature of 370℃. The lower part of the fractionation tower yields the basic aromatic components, while the first side stream yields a light aromatic oil with a density (at 20℃) of 0.76 g / cm³. 3 Medium-quality aromatic oil was extracted from the second to fifth lateral lines, with a density (20℃) of 0.811 g / cm³. 3 .

[0100] The aromatic basic component is passed through a first tubular heater, and air is injected into the furnace tubes of the first tubular heater. The ratio of air flow rate to the weight of the aromatic basic component is 1:100. The air flow rate is in L / min, and the weight of the aromatic basic component is in kg. The outlet temperature of the first tubular heater is 390℃. The heated aromatic basic component enters the first reactor for a cross-linking reaction at a reaction temperature of 400℃. The residence time of the material in the first reactor is 8 hours. The pressure is 0.8 MPa for the first 4 hours and 20 kPa for the last 4 hours. After the reaction, binder asphalt and high-temperature oil gas are generated, including medium-quality aromatic oil and light oil gas. The binder asphalt is cooled into sheets by a binder asphalt sheeting machine to obtain cooled and sheeted binder asphalt. Tests revealed that the softening point of the obtained binder asphalt was 110℃, the coking value was 56%, the content of quinoline insoluble matter was 3%, the content of toluene insoluble matter was 25%, the ash content was 0.0018%, the content of mesophase with a size greater than 10μm was 0%, and the content of mesophase with a size less than 10μm was 0.3%.

[0101] Steam is injected into the furnace tubes of the second tubular heater, and the steam flow rate and the weight ratio of the binder asphalt are 2:100 before heating. The steam flow rate is measured in L / min, and the weight of the binder asphalt is measured in kg. The outlet temperature of the second tubular heater is 430℃. The heated binder asphalt enters the second reactor for pressure swing pyrolysis. The internal temperature of the second reactor is maintained at 420℃, and the material residence time is 6 hours. The pressure inside the second reactor is 3 MPa for the first 3 hours of the reaction and 5 kPa for the last 3 hours. After the reaction, the mesophase binder asphalt and high-temperature oil and gas (including medium-quality aromatic oil and light oil and gas) are cooled into sheets by a mesophase binder asphalt sheeter to obtain cooled mesophase binder asphalt sheets. Tests revealed that the softening point of the mesophase binder asphalt was 170℃, the coking value was 63%, the content of quinoline insolubles was 7%, the content of toluene insolubles was 37%, the ash content was 0.0027%, and the mesophase content was 52%, with the mesophase consisting of small spheres with a size of 10-30μm.

[0102] High-temperature oil and gas (containing medium-quality aromatic oil and light oil and gas) are collected from the top of the fractionation tower, the first reactor, and the second reactor. The high-temperature oil and gas are then recovered using the first vacuum unit, specifically including:

[0103] The high-temperature oil and gas first enter the first oil and gas buffer tank at a temperature of 210℃ for heating and separation to separate the medium-quality aromatic oil. Then, it passes through the first condenser to separate the light oil. The condensing medium of the first condenser is cooling water at a temperature of 5℃. The non-condensable vapor enters the first cryogenic cooler for cooling. The cooling medium of the first cryogenic cooler is a mixture of water and ethylene glycol at a temperature of -30℃. The pressure of the first vacuum device is 5 kPa.

[0104] The density (20℃) of the medium-quality aromatic oil collected by the first oil-gas buffer tank was 0.793 g / cm³. 3 The density (20℃) of the light oil collected by the first condenser is 0.712 g / cm³. 3 .

[0105] The mesophase asphalt binder is passed through a second heat exchanger and exchanges heat with the high-temperature heat transfer oil therein. After the heat exchange, the temperature of the mesophase asphalt binder is 380°C. Then, the heat-exchanged mesophase asphalt binder enters a third reactor for deep reaction and molecular weight adjustment. The internal temperature of the third reactor is 375°C, and the reaction residence time is 8 hours. After deep reaction, spinning-grade mesophase asphalt and high-temperature oil and gas (containing heavy aromatic oil and oil and gas) are formed. The mixture is discharged from the top of the third reactor through a sixth high-temperature pump via a discharge pipeline. The discharge pipeline outlet is equipped with a heating device with a heating temperature of 340°C. The spinning-grade mesophase asphalt is then filtered through a filter medium, which is a filter layer with a pore size of 300 mesh formed by ceramic particles. After passing through a magnetic field with a magnetic field strength of 0.5T, the spinning-grade mesophase asphalt is cooled into sheets by a spinning-grade mesophase asphalt sheeting machine and discharged. Tests revealed that the spinning-grade mesophase pitch had the following properties: softening point 280℃, coking value 73%, ash content 0.0033%, quinoline insoluble content 36%, toluene insoluble content 72%, mesophase content 100%, and yield 37% (calculated based on the total weight of the starting aromatic feedstock).

[0106] The high-temperature oil and gas extracted from the top of the third reactor first enters the second oil and gas buffer tank in the second vacuum unit, where heavy aromatic oil is separated. It then passes through the second condenser, where medium aromatic oil is separated. The non-condensable vapor enters the second cryocooler for cooling. The temperature of the second oil and gas buffer tank is 190℃, the condensing medium of the second condenser is cooling water at 10℃, and the cooling medium of the second cryocooler is a mixture of water and ethylene glycol at -34℃. The pressure of the second vacuum unit is 5 Pa. The density (20℃) of the heavy aromatic oil collected in the second oil and gas buffer tank is 0.84 g / cm³. 3 The density (20℃) of the medium-grade aromatic oil collected by the second condenser is 0.795 g / cm³. 3 .

[0107] Example 3

[0108] This embodiment provides a process for co-producing binder bitumen and mesophase bitumen, which is implemented using the system for co-producing binder bitumen and mesophase bitumen provided in Example 1. The process includes the following specific steps:

[0109] The distillate oil from catalytic cracking slurry was selected as the first aromatic feedstock, and the hydrogenated wax oil component of ethylene tar was selected as the second aromatic feedstock. The first aromatic feedstock was filtered through a first filter and a second filter to remove solid particles, yielding aromatic feedstock 1*. Aromatic feedstock 1* has an ash content of 9 ppm and a density of 1.12 g / cm³ (20℃). 3The total aromatic hydrocarbon content is 68%, of which, by weight, the percentages of tricyclic aromatic hydrocarbons, tetracyclic aromatic hydrocarbons, pentacyclic aromatic hydrocarbons, and aromatic hydrocarbons with more than five rings are 11%, 68%, 12%, and 9%, respectively. It contains fractions with a distillation range greater than 500°C, which account for 78% of the total distillation range. The sulfur content is 0.3%, and the nitrogen content is 0.2%.

[0110] The second aromatic feedstock has an ash content of 10 ppm and a density of 1.11 g / cm³ (20℃). 3 The total aromatic hydrocarbon content is 90%, of which, by weight, the percentages of tricyclic aromatic hydrocarbons, tetracyclic aromatic hydrocarbons, pentacyclic aromatic hydrocarbons, and aromatic hydrocarbons with more than five rings are 2%, 27%, 60%, and 11%, respectively. It contains fractions with a distillation range greater than 500°C, which account for 75% of the total distillation range. The sulfur content is 0.08%, and the nitrogen content is 0.05%.

[0111] Aromatic raw material 1 * The second aromatic feedstock was mixed online at a weight ratio of 10:3 at a temperature of 110℃ and a linear velocity of 0.4 m / s, resulting in a mixed aromatic oil. This mixed aromatic oil was then passed through a first heat exchanger, where it underwent heat exchange via a heat transfer oil. The mixed aromatic oil, heated to 370℃, entered a fractionation tower for component adjustment and further impurity removal. The fractionation tower operated at a pressure of 20 kPa, with an upper temperature of 120℃ and a lower temperature of 360℃. The lower part of the fractionation tower yielded the basic aromatic components, while the first side stream yielded a light aromatic oil with a density (at 20℃) of 0.72 g / cm³. 3 Medium-quality aromatic oil was extracted from the second to fifth lateral lines, with a density (20℃) of 0.815 g / cm³. 3 .

[0112] The aromatic basic components are passed through a first tubular heater, and air is injected into the furnace tubes of the first tubular heater. The ratio of air flow rate to the weight of the aromatic basic components is 1:100. The air flow rate is in L / min, and the weight of the aromatic basic components is in kg. The outlet temperature of the first tubular heater is 370℃. The heated aromatic basic components enter the first reactor for a cross-linking reaction at a reaction temperature of 390℃. The residence time of the material in the first reactor is 10h. The pressure is 0.9MPa for the first 5h and 10KPa for the last 5h. After the reaction, binder asphalt and high-temperature oil gas, including medium aromatic oil and light oil gas, are generated. The binder asphalt is cooled into sheets by a binder asphalt sheeting machine to obtain cooled and sheeted binder asphalt. Tests revealed that the softening point of the obtained binder asphalt was 120℃, the coking value was 57%, the content of quinoline insoluble matter was 6%, the content of toluene insoluble matter was 29%, the ash content was 0.0018%, the content of mesophase with a size greater than 10μm was 0%, and the content of mesophase with a size less than 10μm was 0.2%.

[0113] Steam is injected into the furnace tubes of the second tubular heater, and the steam flow rate to binder asphalt weight ratio is 2:100 before heating. The steam flow rate is measured in L / min, and the binder asphalt weight is measured in kg. The outlet temperature of the second tubular heater is 400℃. The heated binder asphalt enters the second reactor for pressure swing pyrolysis, maintaining the internal temperature of the second reactor at 390℃ and the material residence time at 6 hours. The pressure inside the second reactor is 3 MPa for the first 3 hours of the reaction and 10 kPa for the last 3 hours. After the reaction, the resulting mesophase binder asphalt and high-temperature oil and gas (including medium-grade aromatic oil and light oil and gas) are cooled into sheets by a mesophase binder asphalt sheeter to obtain cooled mesophase binder asphalt sheets. Tests revealed that the softening point of the mesophase binder asphalt was 160℃, the coking value was 61%, the content of quinoline insolubles was 7%, the content of toluene insolubles was 35%, the ash content was 0.0026%, the mesophase content was 50%, and the mesophase consisted of small spheres with a size of 10-30μm.

[0114] High-temperature oil and gas (containing medium-quality aromatic oil and light oil and gas) are collected from the top of the fractionation tower, the first reactor, and the second reactor. The high-temperature oil and gas are then recovered using the first vacuum unit, specifically including:

[0115] The high-temperature oil and gas first enter the first oil and gas buffer tank at a temperature of 190℃ for heating and separation to separate the medium-quality aromatic oil. Then, it passes through the first condenser to separate the light oil. The condensing medium of the first condenser is cooling water at a temperature of 8℃. The non-condensable vapor enters the first cryogenic cooler for cooling. The cooling medium of the first cryogenic cooler is a mixture of water and ethylene glycol at a temperature of -35℃. The pressure of the first vacuum device is 10 kPa.

[0116] The density (20℃) of the medium-quality aromatic oil collected by the first oil-gas buffer tank was 0.791 g / cm³. 3 The density (20℃) of the light oil collected by the first condenser is 0.695 g / cm³. 3 .

[0117] Mesophase asphalt binder and nitrogen are passed through a second heat exchanger and exchanged with high-temperature heat transfer oil. After heat exchange, the temperature of the mesophase asphalt binder is 390°C. Then, the heat-exchanged mesophase asphalt binder enters a third reactor for deep reaction and molecular weight adjustment. The internal temperature of the third reactor is 410°C, and the reaction residence time is 7 hours. After deep reaction, spinning-grade mesophase asphalt and high-temperature oil and gas (containing heavy aromatic oil and gas) are formed. The mixture is discharged from the top of the third reactor through a sixth high-temperature pump via a discharge pipeline. The discharge pipeline outlet is equipped with a heating device with a heating temperature of 340°C. The spinning-grade mesophase asphalt is then filtered through a filter medium, which is a 400-mesh filter layer formed by ceramic particles. After passing through a magnetic field with a magnetic field strength of 1T, the spinning-grade mesophase asphalt is cooled into sheets by a sheet-forming machine before being discharged. Tests revealed that the spinning-grade mesophase pitch had the following properties: softening point 285℃, coking value 76%, ash content 0.0034%, quinoline insoluble content 38%, toluene insoluble content 76%, mesophase content 100%, and yield 39% (calculated based on the total weight of the starting aromatic feedstock).

[0118] The high-temperature oil and gas extracted from the top of the third reactor first enters the second oil and gas buffer tank in the second vacuum unit, where heavy aromatic oil is separated. It then passes through the second condenser, where medium aromatic oil is separated. The non-condensable vapor enters the second cryocooler for cooling. The temperature of the second oil and gas buffer tank is 190℃. The condensing medium in the second condenser is cooling water at 8℃. The cooling medium in the second cryocooler is a mixture of water and ethylene glycol at -35℃. The pressure of the second vacuum unit is 3 Pa. The density (20℃) of the heavy aromatic oil collected in the second oil and gas buffer tank is 0.834 g / cm³. 3 The density (20℃) of the medium-grade aromatic oil collected by the second condenser is 0.815 g / cm³. 3 .

[0119] Example 4

[0120] This embodiment provides a process for co-producing binder bitumen and mesophase bitumen, which is implemented using the system for co-producing binder bitumen and mesophase bitumen provided in Example 1. The process includes the following specific steps:

[0121] The first and second aromatic raw materials are the same as in Example 2. The desolidification process of the first aromatic raw material and the resulting aromatic raw material 1* are also the same as in Example 2.

[0122] Aromatic raw material 1 * The second aromatic feedstock is mixed online at a weight ratio of 10:1 at a temperature of 130℃ and a linear velocity of 0.3 m / s, yielding a mixed aromatic oil. This mixed aromatic oil is then passed through a first heat exchanger, where it undergoes heat exchange via a heat transfer oil. The mixed aromatic oil, heated to 350℃, enters a fractionation tower for component adjustment and further impurity removal. The fractionation tower operates at a pressure of 25 kPa, with an upper temperature of 130℃ and a lower temperature of 375℃. The lower part of the fractionation tower yields the basic aromatic components, while the first side stream yields a light aromatic oil with a density (at 20℃) of 0.72 g / cm³. 3 Medium-quality aromatic oil was extracted from the second to fifth lateral lines, with a density (20℃) of 0.815 g / cm³. 3 .

[0123] The aromatic basic components are passed through a first tubular heater, and air is injected into the furnace tubes of the first tubular heater. The ratio of air flow rate to the weight of the aromatic basic components is 5:100. The air flow rate is in L / min, and the weight of the aromatic basic components is in kg. The outlet temperature of the first tubular heater is 350℃. The heated aromatic basic components enter the first reactor for a cross-linking reaction. The reaction temperature is 390℃, and the residence time of the material in the first reactor is 10h. The pressure is 0.8MPa for the first 5h and 20KPa for the last 5h. After the reaction, binder asphalt and high-temperature oil gas are generated, including medium-quality aromatic oil and light oil gas. The binder asphalt is cooled into sheets by a binder asphalt sheeting machine to obtain cooled and sheeted binder asphalt. Tests revealed that the softening point of the obtained binder asphalt was 109℃, the coking value was 56%, the content of quinoline insoluble matter was 4%, the content of toluene insoluble matter was 25%, the ash content was 0.0015%, the content of mesophase with a size greater than 10μm was 0%, and the content of mesophase with a size less than 10μm was 0.1%.

[0124] Nitrogen gas is injected into the furnace tubes of the second tubular heater, and the nitrogen flow rate and the weight ratio of the binder asphalt are mixed at 5:100 before heating. The nitrogen flow rate is measured in L / min, the weight of the binder asphalt is measured in kg, and the outlet temperature of the second tubular heater is 430℃. The heated binder asphalt enters the second reactor for pressure swing pyrolysis, maintaining the internal temperature of the second reactor at 420℃ and the material residence time at 4h. For the first 2h of the reaction, the pressure inside the second reactor is 3MPa, and for the last 2h, the pressure inside the second reactor is 10KPa. After the reaction, the resulting mesophase binder asphalt and high-temperature oil and gas (including medium-grade aromatic oil and light oil and gas) are cooled into sheets by a mesophase binder asphalt sheeter to obtain cooled mesophase binder asphalt sheets. Tests revealed that the softening point of the mesophase binder asphalt was 180℃, the coking value was 67%, the content of quinoline insolubles was 9%, the content of toluene insolubles was 41%, the ash content was 0.0023%, and the mesophase content was 50%, with the mesophase consisting of small spheres with a size of 10-30μm.

[0125] High-temperature oil and gas (containing medium-quality aromatic oil and light oil and gas) are collected from the top of the fractionation tower, the first reactor, and the second reactor. The high-temperature oil and gas are then recovered using the first vacuum unit, specifically including:

[0126] The high-temperature oil and gas first enter the first oil and gas buffer tank at a temperature of 200℃ for heating and separation to separate the medium-quality aromatic oil. Then, it passes through the first condenser to separate the light oil. The condensing medium of the first condenser is cooling water at a temperature of 10℃. The non-condensable vapor enters the first cryogenic cooler for cooling. The cooling medium of the first cryogenic cooler is a mixture of water and ethylene glycol at a temperature of -30℃. The pressure of the first vacuum device is 1 kPa.

[0127] The density (20℃) of the medium-quality aromatic oil collected by the first oil-gas buffer tank was 0.815 g / cm³. 3 The density (20℃) of the light oil collected by the first condenser is 0.710 g / cm³. 3 .

[0128] Mesophase asphalt binder and nitrogen are passed through a second heat exchanger and exchanged with high-temperature heat transfer oil. After heat exchange, the temperature of the mesophase asphalt binder is 410°C. Then, the heat-exchanged mesophase asphalt binder enters a third reactor for deep reaction and molecular weight adjustment. The internal temperature of the third reactor is 400°C, and the reaction residence time is 5 hours. After deep reaction, spinning-grade mesophase asphalt and high-temperature oil and gas (containing heavy aromatic oil and oil and gas) are formed. The mixture is discharged from the top of the third reactor through a sixth high-temperature pump via a discharge pipeline. The discharge pipeline outlet is equipped with a heating device with a heating temperature of 340°C. The spinning-grade mesophase asphalt is then filtered through a filter medium, which is a 400-mesh filter layer formed by ceramic particles. After passing through a magnetic field with a magnetic field strength of 1T, the spinning-grade mesophase asphalt is cooled into sheets by a spinning-grade mesophase asphalt sheeter and discharged. Tests revealed that the spinning-grade mesophase pitch had the following properties: softening point 282℃, coking value 75%, ash content 0.0037%, quinoline insoluble content 35%, toluene insoluble content 72%, mesophase content 100%, and yield 42% (calculated based on the total weight of the starting aromatic feedstock).

[0129] The high-temperature oil and gas extracted from the top of the third reactor first enters the second oil and gas buffer tank in the second vacuum unit, where heavy aromatic oil is separated. It then passes through the second condenser, where medium aromatic oil is separated. The non-condensable vapor enters the second cryocooler for cooling. The temperature of the second oil and gas buffer tank is 210℃, the condensing medium of the second condenser is cooling water at 5℃, and the cooling medium of the second cryocooler is a mixture of water and ethylene glycol at -30℃. The pressure of the second vacuum unit is 10 Pa. The density (20℃) of the heavy aromatic oil collected in the second oil and gas buffer tank is 0.853 g / cm³. 3 The density (20℃) of the medium-grade aromatic oil collected by the second condenser is 0.812 g / cm³. 3 .

[0130] Comparative Example 1

[0131] This comparative example provides a process for producing binder bitumen, wherein the process includes the following specific steps:

[0132] Catalytic cracking slurry was selected as the first aromatic feedstock. After solid particles were removed by filtration in the first and second filters, aromatic feedstock 1* was obtained. Aromatic feedstock 1* had an ash content of 6 ppm and a density of 1.02 g / cm³ (20℃). 3The total aromatic hydrocarbon content is 62%, of which, by weight, the percentages of tricyclic aromatic hydrocarbons, tetracyclic aromatic hydrocarbons, pentacyclic aromatic hydrocarbons, and aromatic hydrocarbons with more than five rings are 17%, 61%, 13%, and 9%, respectively. It contains fractions with a distillation range greater than 500°C, which account for 52% of the total distillation range. The sulfur content is 0.24%, and the nitrogen content is 0.1%.

[0133] Aromatic feedstock 1* is reacted in an intermittently electrically heated reactor at a reaction temperature of 420℃ and a residence time of 12h. The pressure is 0.8MPa for the first 6h and 20KPa for the last 6h. After the reaction, binder asphalt, medium-quality aromatic oil, and light oil and gas are produced.

[0134] Tests revealed that the softening point of the obtained binder bitumen was 90℃, the coking value was 46%, the content of quinoline insoluble matter was 10%, the content of toluene insoluble matter was 32%, the ash content was 0.0014%, the content of mesophase with a size greater than 10μm was 3%, and the content of mesophase with a size less than 10μm was 1%.

[0135] Comparative Example 2

[0136] This comparative example provides a process for producing mesophase binder bitumen, wherein the process includes the following specific steps:

[0137] Catalytic cracking slurry was selected as the first aromatic feedstock. After solid particles were removed by filtration in the first and second filters, aromatic feedstock 1* was obtained. Aromatic feedstock 1* had an ash content of 6 ppm and a density of 1.02 g / cm³ (20℃). 3 The total aromatic hydrocarbon content is 62%, of which, by weight, the percentages of tricyclic aromatic hydrocarbons, tetracyclic aromatic hydrocarbons, pentacyclic aromatic hydrocarbons, and aromatic hydrocarbons with more than five rings are 17%, 61%, 13%, and 9%, respectively. It contains fractions with a distillation range greater than 500°C, which account for 52% of the total distillation range. The sulfur content is 0.24%, and the nitrogen content is 0.1%.

[0138] Aromatic feedstock 1* is reacted in an intermittently electrically heated reactor, with a residence time of 12 hours. The reaction temperature is 420°C and the pressure is 2 MPa for the first 8 hours, and the reaction temperature is 410°C and the pressure is 20 kPa for the last 4 hours. After the reaction is completed, mesophase binder asphalt, medium-quality aromatic oil, and light oil and gas are produced.

[0139] Tests revealed that the properties of the obtained mesophase binder bitumen were as follows: softening point 150℃, coking value 56%, quinoline insoluble content 12%, toluene insoluble content 45%, ash content 0.0021%, and mesophase content 40%. The mesophase is a plate-like structure with an irregular shape and a size of 10-200μm.

[0140] Comparative Example 3

[0141] This comparative example provides a process for producing mesophase binder bitumen, wherein the process includes the following specific steps:

[0142] Catalytic cracking slurry was selected as the first aromatic feedstock. After solid particles were removed by filtration in the first and second filters, aromatic feedstock 1* was obtained. Aromatic feedstock 1* had an ash content of 6 ppm and a density of 1.02 g / cm³ (20℃). 3 The total aromatic hydrocarbon content is 62%, of which, by weight, the percentages of tricyclic aromatic hydrocarbons, tetracyclic aromatic hydrocarbons, pentacyclic aromatic hydrocarbons, and aromatic hydrocarbons with more than five rings are 17%, 61%, 13%, and 9%, respectively. It contains fractions with a distillation range greater than 500°C, which account for 52% of the total distillation range. The sulfur content is 0.24%, and the nitrogen content is 0.1%.

[0143] Aromatic feedstock 1* was reacted in an intermittently electrically heated reactor at a temperature of 410℃ and a residence time of 12 h. The pressure was 2 MPa for the first 10 h and 10 kPa for the last 2 h. After the reaction, mesophase-containing asphalt, medium-quality aromatic oil, and light oil gas were produced. The obtained mesophase-containing asphalt was placed in a heated high-speed centrifuge and centrifuged at 200℃ and 1200 r / min. The results showed that the softening point of the obtained mesophase asphalt was 250℃, the coking value was 52%, the content of quinoline insolubles was 18%, the content of toluene insolubles was 61%, the ash content was 0.0028%, the mesophase content was 90%, and the yield was 12% (calculated based on the starting aromatic feedstock).

[0144] Comparing the property parameters of the mesophase binder bitumen in Examples 2-4 and Comparative Example 3, it can be seen that the mesophase binder bitumen prepared in Examples 2-4 of the present invention has better performance than the mesophase binder bitumen in Comparative Example 2.

[0145] Comparative Example 4

[0146] This comparative example provides a process for producing mesophase binder bitumen, which differs from Example 2 mainly in that it uses only aromatic raw material 1* as the raw material, and includes the following specific steps:

[0147] The same catalytic cracking slurry as in Example 2 was selected as the first aromatic feedstock. After removing solid particles through a first filter and a second filter, aromatic feedstock 1* was obtained. The ash content of aromatic feedstock 1* was 6 ppm, and its density was 1.02 g / cm³ (20°C). 3The total aromatic hydrocarbon content is 62%, of which, by weight, the percentages of tricyclic aromatic hydrocarbons, tetracyclic aromatic hydrocarbons, pentacyclic aromatic hydrocarbons, and aromatic hydrocarbons with more than five rings are 17%, 61%, 13%, and 9%, respectively. It contains fractions with a distillation range greater than 500°C, which account for 52% of the total distillation range. The sulfur content is 0.24%, and the nitrogen content is 0.1%.

[0148] Aromatic feedstock 1* is passed through a first heat exchanger and heated to 380°C via heat transfer oil. After heat exchange, aromatic feedstock 1* enters a fractionation tower for component adjustment and further impurity removal. The fractionation tower operates at a pressure of 49 kPa, with an upper temperature of 140°C and a lower temperature of 370°C. The lower part of the fractionation tower yields the basic aromatic components, while the first side stream yields a light aromatic oil with a density (20°C) of 0.72 g / cm³. 3 Medium-quality aromatic oil was extracted from the second to fifth lateral lines, with a density (20℃) of 0.832 g / cm³. 3 .

[0149] The aromatic basic component is passed through a first tubular heater, and air is injected into the furnace tubes of the first tubular heater. The ratio of air flow rate to the weight of the aromatic basic component is 1:100. The air flow rate is in L / min, and the weight of the aromatic basic component is in kg. The outlet temperature of the first tubular heater is 390℃. The heated aromatic basic component enters the first reactor for a cross-linking reaction at a reaction temperature of 400℃. The residence time of the material in the first reactor is 8 hours. The pressure is 0.8 MPa for the first 4 hours and 20 kPa for the last 4 hours. After the reaction, binder asphalt and high-temperature oil gas are generated, including medium-quality aromatic oil and light oil gas. The binder asphalt is cooled into sheets by a binder asphalt sheeting machine to obtain cooled and sheeted binder asphalt. Tests revealed that the softening point of the obtained binder asphalt was 78℃, the coking value was 39%, the content of quinoline insoluble matter was 0%, the content of toluene insoluble matter was 15%, the ash content was 0.0031%, the content of mesophase with a size greater than 10μm was 0%, and the content of mesophase with a size less than 10μm was 0%.

[0150] Steam is injected into the furnace tubes of the second tubular heater, and the steam flow rate and the weight ratio of the binder asphalt are 2:100 before heating. The steam flow rate is measured in L / min, and the weight of the binder asphalt is measured in kg. The outlet temperature of the second tubular heater is 430℃. The heated binder asphalt enters the second reactor for pressure swing pyrolysis. The internal temperature of the second reactor is maintained at 420℃, and the material residence time is 6 hours. The pressure inside the second reactor is 3 MPa for the first 3 hours of the reaction and 5 kPa for the last 3 hours. After the reaction, the mesophase binder asphalt and high-temperature oil and gas (including medium-quality aromatic oil and light oil and gas) are cooled into sheets by a mesophase binder asphalt sheeter to obtain cooled mesophase binder asphalt sheets. Tests revealed that the softening point of the mesophase binder asphalt was 132℃, the coking value was 47%, the content of quinoline insolubles was 2%, the content of toluene insolubles was 25%, the ash content was 0.0036%, and the mesophase content was 11%, with the mesophase consisting of small spheres with a size of 30-100μm.

[0151] High-temperature oil and gas (containing medium-quality aromatic oil and light oil and gas) are collected from the top of the fractionation tower, the first reactor, and the second reactor. The high-temperature oil and gas are then recovered using the first vacuum unit, specifically including:

[0152] The high-temperature oil and gas first enter the first oil and gas buffer tank at a temperature of 210℃ for heating and separation to separate the medium-quality aromatic oil. Then, it passes through the first condenser to separate the light oil. The condensing medium of the first condenser is cooling water at a temperature of 5℃. The non-condensable vapor enters the first cryogenic cooler for cooling. The cooling medium of the first cryogenic cooler is a mixture of water and ethylene glycol at a temperature of -30℃. The pressure of the first vacuum device is 5 kPa.

[0153] The density (20℃) of the medium-quality aromatic oil collected by the first oil-gas buffer tank was 0.752 g / cm³. 3 The density (20℃) of the light oil collected by the first condenser is 0.701 g / cm³. 3 .

[0154] The mesophase asphalt binder is passed through a second heat exchanger and exchanges heat with the high-temperature heat transfer oil therein. After the heat exchange, the temperature of the mesophase asphalt binder is 380°C. Then, the heat-exchanged mesophase asphalt binder enters a third reactor for deep reaction and molecular weight adjustment. The internal temperature of the third reactor is 375°C, and the reaction residence time is 8 hours. After deep reaction, mesophase asphalt and high-temperature oil and gas (containing heavy aromatic oil and gas) are formed. The mixture is discharged from the top of the third reactor through a sixth high-temperature pump via a discharge pipeline. The discharge pipeline outlet is equipped with a heating device with a heating temperature of 340°C. The mesophase asphalt is then filtered through a filter medium, which is a filter layer with a pore size of 300 mesh formed by ceramic particles. After passing through a magnetic field with a magnetic field strength of 0.5T, it is cooled into sheets by a spinning-grade mesophase asphalt sheeter and discharged. Tests revealed that the mesophase pitch had the following properties: softening point 210℃, coking value 58%, ash content 0.0042%, quinoline insoluble content 21%, toluene insoluble content 57%, mesophase content 90%, and yield 14% (calculated based on the total weight of the starting aromatic feedstock).

[0155] The high-temperature oil and gas extracted from the top of the third reactor first enters the second oil and gas buffer tank in the second vacuum unit, where heavy aromatic oil is separated. It then passes through the second condenser, where medium aromatic oil is separated. The non-condensable vapor enters the second cryocooler for cooling. The temperature of the second oil and gas buffer tank is 190℃, the condensing medium of the second condenser is cooling water at 10℃, and the cooling medium of the second cryocooler is a mixture of water and ethylene glycol at -34℃. The pressure of the second vacuum unit is 5 Pa. The density (20℃) of the heavy aromatic oil collected in the second oil and gas buffer tank is 0.84 g / cm³. 3 The density (20℃) of the medium-grade aromatic oil collected by the second condenser is 0.761 g / cm³. 3 .

[0156] Comparative Example 5

[0157] This comparative example provides a process for producing mesophase binder bitumen, wherein the process includes the following specific steps:

[0158] The same catalytic cracking slurry as in Example 2 was used as the first aromatic feedstock, and the same heavy distillate of ethylene tar as in Example 2 was used as the second aromatic feedstock. The first aromatic feedstock was filtered through a first filter and a second filter to remove solid particles, yielding aromatic feedstock 1*. Aromatic feedstock 1* had an ash content of 6 ppm and a density of 1.02 g / cm³ (20°C). 3The total aromatic hydrocarbon content is 62%, of which, by weight, the percentages of tricyclic aromatic hydrocarbons, tetracyclic aromatic hydrocarbons, pentacyclic aromatic hydrocarbons, and aromatic hydrocarbons with more than five rings are 17%, 61%, 13%, and 9%, respectively. It contains fractions with a distillation range greater than 500°C, which account for 52% of the total distillation range. The sulfur content is 0.24%, and the nitrogen content is 0.1%.

[0159] The ash content of aromatic feedstock 2 is 10 ppm, and its density is 1.11 g / cm³ (20℃). 3 The total aromatic hydrocarbon content is 90%, of which, by weight, the percentages of tricyclic aromatic hydrocarbons, tetracyclic aromatic hydrocarbons, pentacyclic aromatic hydrocarbons, and aromatic hydrocarbons with more than five rings are 5%, 32%, 51%, and 12%, respectively. It contains fractions with a distillation range greater than 500°C, which account for 73% of the total distillation range. The sulfur content is 0.2% and the nitrogen content is 0.1%.

[0160] Aromatic raw material 1 * The second aromatic feedstock was mixed online at a weight ratio of 10:1 at a temperature of 100℃ and a linear velocity of 0.5m / s. After online mixing, a mixed aromatic oil was obtained. The mixed aromatic oil was then reacted in an intermittently electrically heated reactor at a temperature of 420℃ and a residence time of 12h. The pressure was 0.8MPa for the first 6h and 20KPa for the last 6h. After the reaction, binder asphalt, medium aromatic oil, and light oil gas were generated.

[0161] Tests revealed that the softening point of the obtained binder asphalt was 82℃, the coking value was 39%, the content of quinoline insoluble matter was 18%, the content of toluene insoluble matter was 24%, the ash content was 0.0012%, the content of mesophase with a size greater than 10μm was 2%, and the content of mesophase with a size less than 10μm was 1%.

[0162] The above-mentioned binder asphalt was allowed to continue to react in an intermittently electrically heated reactor for a residence time of 12 hours. The reaction temperature was 420°C and the pressure was 2 MPa for the first 8 hours, and the reaction temperature was 410°C and the pressure was 20 kPa for the last 4 hours. After the reaction was completed, mesophase binder asphalt, medium-quality aromatic oil, and light oil and gas were generated.

[0163] Tests revealed that the properties of the obtained mesophase binder bitumen were as follows: softening point 130℃, coking value 41%, quinoline insoluble content 15%, toluene insoluble content 32%, ash content 0.0023%, and mesophase content 20%. The mesophase is a plate-like structure with an irregular shape and a size of 10-200μm.

[0164] Comparative Example 6

[0165] This comparative example provides a process for producing mesophase binder bitumen, wherein the process includes the following specific steps:

[0166] The first and second aromatic feedstocks are the same as in Example 2, and the subsequent processing procedures are also the same. Aromatic feedstock 1 * The aromatic base component obtained by mixing and processing the second aromatic feedstock according to the conditions of Example 2 is passed through a first tubular heater with no gas injection into the furnace tubes and an outlet temperature of 390°C. The heated aromatic base component then enters a first reactor for a thermal polymerization reaction at 400°C. The residence time of the material in the first reactor is 8 hours, with a pressure of 0.8 MPa for the first 4 hours and 20 kPa for the last 4 hours. The reaction produces binder pitch and high-temperature oil and gas, including medium-grade aromatic oil and light oil and gas. The binder pitch is cooled into sheets using a binder pitch sheeter to obtain cooled binder pitch sheets. Testing revealed that the obtained binder pitch has a softening point of 68°C, a coking value of 23%, a quinoline-insoluble content of 2%, a toluene-insoluble content of 16%, an ash content of 0.0018%, a mesophase content greater than 10 μm of 0%, and a mesophase content less than 10 μm of 0.6%.

[0167] Under conditions of no gas injection into the furnace tubes of the second tubular heater and an outlet temperature of 430°C, the heated binder pitch is introduced into the second reactor for pressure swing pyrolysis. The internal temperature of the second reactor is maintained at 420°C, and the material residence time is 6 hours. For the first 3 hours of the reaction, the pressure inside the second reactor is 3 MPa, and for the next 3 hours, it is 5 kPa. The reaction is terminated in the 4th hour due to coking and blockage of the furnace tubes. The resulting mesophase binder pitch and high-temperature oil and gas (including medium-grade aromatic oil and light oil and gas) are then cooled into flakes using a mesophase binder pitch flake forming machine to obtain cooled mesophase binder pitch flakes. Tests revealed that the softening point of the mesophase binder asphalt was 130℃, the coking value was 36%, the content of quinoline insolubles was 5%, the content of toluene insolubles was 28%, the ash content was 0.0021%, and the mesophase content was 12%, with the mesophase consisting of small spheres with a size of 5-10μm.

[0168] This comparative example did not undergo further reaction.

[0169] Test Example 1

[0170] In this test example, the binder asphalt and needle coke particles prepared in Examples 2-4 and Comparative Example 1 were mixed and extruded in a certain proportion, and then carbonized and graphitized in sequence to obtain graphite electrodes. The relevant physical properties of the graphite electrodes, such as thermal expansion coefficient, resistivity, compressive strength and bulk density, were tested.

[0171] Before testing the relevant physical properties, the binder asphalt and needle coke need to be prepared into samples of a certain shape. For the specific operation steps of preparing samples of a certain shape, refer to T / ZGTS 002-2019 Oil-based needle coke for graphite electrodes, Appendix: Preparation method of thermal expansion coefficient sample of oil-based needle coke for graphite electrodes.

[0172] The coefficient of thermal expansion of the graphite electrode was tested according to GB / T3074.4, the method for determining the coefficient of thermal expansion (CTE) of graphite electrode; the compressive strength was tested according to GB / T1431-2019, the method for testing the compressive strength of carbon materials; the bulk density was tested according to YB / T 119-1997, the method for determining the bulk density of carbon materials; and the resistivity was tested according to YB / T120-1997, the method for determining the resistivity of carbon materials. The test results are shown in Table 1 below.

[0173] Table 1

[0174] Comparing the properties of the binder bitumen in Examples 2-4 and Comparative Examples 1, 4-6, it can be seen that the binder bitumen prepared in Examples 2-4 of this invention has superior performance compared to the binder bitumen in Comparative Example 1. As shown in Table 1 above, the graphite electrodes prepared with the binder bitumen in Examples 2-4 of this invention also have better performance than the graphite electrodes prepared with the binder bitumen in Comparative Examples 1 and 4-6.

[0175] Test Example 2

[0176] In this test example, the mesophase binder pitch and petroleum coke or pitch coke powder prepared in Examples 2-4 and Comparative Example 2 were mixed, isostatically pressed, carbonized, and graphitized to obtain special graphite. The thermal expansion coefficient, resistivity, compressive strength and bulk density of the special graphite were tested.

[0177] Before testing the relevant physical properties, it is necessary to prepare samples of the mesophase binder pitch and petroleum coke or pitch coke into a certain shape. The specific steps for preparing samples of a certain shape include: first, selecting representative calcined petroleum coke with a particle size of less than 30 mm, and reducing it to about 4 kg according to the specifications of TZGTS002-2019 "Oil-based Needle Coke for Graphite Electrodes"; then crushing it to less than 1 mm, and then reducing it to about 1 kg using the quartering method, and putting it into a ball mill for fine grinding. After fine grinding, the particle size composition is controlled so that the weight ratio of powder with a size of less than 10 μm is 50 ± 2%.

[0178] Take approximately 1 kg of mesophase binder pitch and grind it finely in a ball mill. After fine grinding, the particle size distribution should be controlled such that the weight percentage of particles smaller than 3 μm is 50 ± 2%. Mix the ground petroleum coke powder with the mesophase binder pitch evenly to obtain a mixture. Then, knead this mixture in a preheated kneading pot with a volume of approximately 1 L. The kneaded sample is 1.1 kg, the kneading temperature is 190-210℃, and the kneading time is approximately 1 hour. The amount of binder (electrode pitch) depends on the degree of adsorption, and is generally approximately 27-28%. The weight percentage of the ground petroleum coke powder was calculated as 100%. The powder was then rolled and cooled. It was then ground a second time to make the weight percentage of powder with a particle size of less than 25 μm 50 ± 2%. The powder was then isostatically pressed into a round bar-shaped sample with a diameter of 30 mm and a length of 80 mm under a pressure of 35 MPa. The sample was then calcined and graphitized to obtain special graphite. The thermal expansion coefficient, resistivity, compressive strength and bulk density of the special graphite were then tested according to the test method in Test Example 1. The test results are shown in Table 2 below.

[0179] Table 2

[0180] Comparing the property parameters of the mesophase binder pitch in Examples 2-4 and Comparative Example 2, it can be seen that the mesophase binder pitch prepared in Examples 2-4 of this invention has superior performance compared to the mesophase binder pitch in Comparative Example 2. From the data in Table 2 above, it can be seen that the performance of the special graphite prepared from the mesophase binder pitch of Examples 2-4 of this invention is also superior to that prepared from the mesophase binder pitch of Comparative Example 2. In Comparative Examples 4 and 5, due to the large size distribution range of the mesophase in the binder pitch, the products are not uniform. Therefore, Table 2 shows that the test values ​​of their thermal expansion coefficient, resistivity, compressive strength, and bulk density are all within a certain range. Such products cannot be used for the preparation of products with uniform quality.

[0181] Test Example 3

[0182] In this test example, the spinning-grade mesophase pitch prepared in Examples 2-4 and the mesophase binder pitch prepared in Comparative Example 2 were melt-spun and then subjected to oxidation, carbonization, and graphitization treatments to obtain carbon fibers. The relevant physical properties of the carbon fibers, such as diameter, tensile strength, elastic modulus, and thermal conductivity, were tested.

[0183] The specific preparation method of carbon fiber includes: first, placing spinning-grade mesophase pitch into the cavity of a spinning machine and heating it to 315℃, using nitrogen as the pressurized spinning gas at a pressure of 1.5MPa. Under these conditions, the spinning-grade mesophase pitch softens and is forced into a 0.2mm spinning hole by nitrogen gas. The raw filament is collected into a roll by a take-up spool rotating at 600r / min. After melt spinning, oxidation is performed at a temperature of 300℃, an air flow rate of 100mL / min, and an oxidation time of 1h. After oxidation, carbonization is performed at a temperature of 700℃, with nitrogen gas introduced and the flow rate controlled at 200mL / min, for a carbonization time of 2h. After carbonization, graphitization is performed at a temperature of 2900℃, with argon gas introduced and the flow rate controlled at 100mL / min, for a graphitization time of 1h. After the treatment, carbon fiber is obtained.

[0184] The diameter of carbon fiber was tested according to GB / T 29762-2013, "Determination of diameter and cross-sectional area of ​​carbon fiber", and the tensile strength of carbon fiber was tested according to GB / T 31290-2014, "Determination of tensile properties of carbon fiber monofilament". The test results are shown in Table 3 below.

[0185] Table 3

[0186] As can be seen from the data in Table 3 above, the carbon fibers obtained from the spinning-grade mesophase pitch of Examples 2-4 of this invention also have better performance than the carbon fibers obtained from the mesophase binder pitch of Comparative Example 2. The mesophase pitch formed in Comparative Example 4 cannot be continuously spun and cannot form continuous filaments, so the test data shown in Table 3 above cannot be obtained.

[0187] The above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, any substitution of equivalent components or equivalent changes and modifications made within the scope of protection of this patent should still fall within the scope of this patent. Furthermore, the technical features, technical features and technical inventions, and technical inventions in this invention can be freely combined and used.

Claims

1. A process for co-producing binder bitumen and mesophase bitumen, characterized in that, The process for co-producing binder bitumen and mesophase bitumen includes: Step (a): Filter the first aromatic feedstock to obtain aromatic feedstock 1*, mix aromatic feedstock 1* and the second aromatic feedstock to obtain mixed aromatic oil; heat the mixed aromatic oil and then distill it to obtain the basic aromatic components; Step (b): The aromatic base components and crosslinking gas are heated to carry out a crosslinking reaction to obtain the binder asphalt; Step (c): The binder bitumen and stripping gas are heated and then subjected to pressure swing pyrolysis to obtain mesophase binder bitumen; Step (d): Allow the heated mesophase binder pitch to undergo a deep reaction to obtain spinning-grade mesophase pitch.

2. The process according to claim 1, characterized in that, The process further includes step (e): using a first vacuum device to sequentially heat and separate, condense and separate, and cryogenically treat the high-temperature oil and gas generated in step (a), the crosslinking reaction in step (b), and the pressure swing pyrolysis in step (c); and using a second vacuum device to sequentially heat and separate, condense and separate, and cryogenically treat the high-temperature oil and gas generated in step (d) through the deep reaction.

3. The process according to claim 2, characterized in that, The temperatures for the heating separation, the condensation separation, and the cryogenic treatment are 190-220℃, 2-10℃, and -40 to -30℃, respectively. The pressure of the first vacuum system is 1KPa-1MPa, and the pressure of the second vacuum device is 1-10Pa.

4. The process according to any one of claims 1-3, characterized in that, The first aromatic feedstock includes one or a combination of several of the following: catalytic cracking slurry oil or its distillate oil, catalytic cycle oil or its distillate oil, solvent-de-oiled asphalt or its distillate oil, and thermal cracking residue oil or its distillate oil. The second aromatic feedstock includes one or a combination of several of the following: ethylene tar or its distillate oil, hydrogenated ethylene tar wax oil or its distillate oil, and deasphalted vacuum residue oil or its distillate oil.

5. The process according to claim 4, characterized in that, The total aromatic hydrocarbon content in the second aromatic hydrocarbon feedstock is 80-95%, of which the contents of tricyclic aromatic hydrocarbons, tetracyclic aromatic hydrocarbons, pentacyclic aromatic hydrocarbons and aromatic hydrocarbons with more than five rings are 1-5%, 25-35%, 50-60% and 10-20% respectively, based on the total weight of the total aromatic hydrocarbons. It contains components with a distillation range greater than 400°C, of ​​which the fraction with a distillation range of 500°C or higher accounts for 70-90% of the total distillation range. The total aromatic hydrocarbon content in the aromatic hydrocarbon feedstock 1* is 60-80%, wherein, based on the total weight of the total aromatic hydrocarbons, the contents of tricyclic aromatic hydrocarbons, tetracyclic aromatic hydrocarbons, pentacyclic aromatic hydrocarbons, and aromatic hydrocarbons with more than five rings are 10-20%, 60-70%, 10-20%, and 5-10%, respectively. It contains components with a distillation range greater than 400°C, wherein the fraction with a distillation range of 500°C or higher accounts for 50-80% of the total distillation range.

6. The process according to claim 1, characterized in that, In step (a), aromatic raw material 1* and the second aromatic raw material are mixed in a weight ratio of 10:1-3 to obtain a mixed aromatic oil. The mixing temperature is 100-150℃ and the linear velocity is 0.3-0.5m / s.

7. The process according to claim 1 or 6, characterized in that, In step (a), the distillation is a reduced pressure operation with a pressure of 20-50 kPa. The upper temperature of the distillation apparatus is 120-150°C, and the lower temperature is 360-380°C. The lower part yields the basic aromatic components.

8. The process according to claim 1, characterized in that, In step (b), the crosslinking gas and the aromatic basic component are mixed at a crosslinking gas flow rate to aromatic basic component weight ratio of 1-5:100 and then heated to 350-410℃. The crosslinking gas flow rate is in L / min and the aromatic basic component weight is in kg.

9. The process according to claim 1 or 8, characterized in that, In step (b), the temperature of the crosslinking reaction is 380-410℃, the residence time of the material is 8-10h, the pressure is adjusted to 0.8-0.9MPa for the first 4-5h, and the pressure is adjusted to 10-30KPa for the last 4-5h.

10. The process according to claim 1, characterized in that, In step (c), stripping gas and binder asphalt are mixed at a ratio of stripping gas flow rate to binder asphalt weight of 1-5:100 and then heated to 400-430℃. The stripping gas flow rate is in L / min and the binder asphalt weight is in kg.

11. The process according to claim 1 or 10, characterized in that, In step (c), the temperature of the pressure swing pyrolysis is 390-420℃, the residence time of the binder asphalt is 4-8h, the pressure is adjusted to 3-5MPa for the first 2-4 hours, and the pressure is adjusted to 5-20KPa for the last 2-4 hours.

12. The process according to claim 1, characterized in that, Step (d) further includes: discharging the spinning-grade mesophase pitch at a heating temperature of 330-350℃ and filtering it through a filter medium during the discharge process. The filter medium is a filter layer with a pore size of 300-400 mesh formed by ceramic particles. Then, the filtered pitch is passed through a magnetic field with a magnetic field strength of 0.5-1T perpendicular to the discharge pipeline. Finally, the pitch is cooled into flakes by a spinning-grade mesophase pitch flake machine and discharged to obtain cooled and flake-shaped spinning-grade mesophase pitch.

13. The process according to claim 1 or 12, characterized in that, In step (d), the temperature of the heated mesophase binder bitumen is 380-410℃.

14. The process according to claim 1 or 12, characterized in that, In step (d), the temperature of the deep reaction is 370-410℃, and the material residence time is 4-8h.

15. A system for co-producing binder bitumen and mesophase bitumen according to any one of claims 1-14, characterized in that, The system for co-producing binder bitumen and mesophase bitumen includes: The system comprises a first aromatics feed tank, a second aromatics feed tank, an aromatics feed tank 1*, a filtration device, a first heat exchanger, a distillation device, a gas source, a first heating device, a first reactor, a second heating device, a second reactor, a second heat exchanger, and a third reactor. The first aromatic feed tank is connected to the inlet of the aromatic feed 1* tank via a pipeline and a filter device. The outlets of the aromatic feed 1* tank and the second aromatic feed tank are connected to the inlet of the distillation unit via a pipeline and a first heat exchanger. The aromatic basic component outlet of the distillation unit is connected to the inlet of the first reactor via a pipeline and a first heating device. The gas source is connected to the first heating device via a pipeline. The binder pitch outlet of the first reactor is connected to the inlet of the second reactor via a pipeline and a second heating device. The mesophase binder pitch outlet of the second reactor is connected to the inlet of the third reactor via a pipeline and a second heat exchanger.

16. The system according to claim 15, characterized in that, The system further includes a first vacuum device and a second vacuum device. The high-temperature oil and gas outlets of the distillation device, the first reactor, and the second reactor are respectively connected to the first vacuum device via pipelines. The high-temperature oil and gas outlet of the third reactor is connected to the second vacuum device via pipelines. The first vacuum device includes a first oil and gas buffer tank, a first condenser, a first cryogenic heater, and a first vacuum unit connected in sequence via pipelines. The second vacuum device includes a second oil and gas buffer tank, a second condenser, a second cryogenic heater, and a second vacuum unit connected in sequence via pipelines.

17. The system according to claim 15 or 16, characterized in that, The system also includes a ceramic filter, an external magnetic strip, and a spinning-grade mesophase pitch flake machine. The spinning-grade mesophase pitch outlet of the third reactor is connected to the spinning-grade mesophase pitch flake machine via a pipeline through the ceramic filter and the external magnetic strip in sequence. A heat tracing device is installed on the pipeline between the spinning-grade mesophase pitch outlet of the third reactor and the ceramic filter.

18. The system according to claim 15 or 16, characterized in that, The system also includes a binder asphalt buffer tank and a binder asphalt flake machine. The binder asphalt outlet of the first reactor is connected to the inlet of the second reactor via a pipeline through the binder asphalt buffer tank and the second heating device. The binder asphalt buffer tank is also connected to the binder asphalt flake machine via a pipeline.

19. The system according to claim 15 or 16, characterized in that, The system also includes a mesophase binder asphalt buffer tank and a mesophase binder asphalt flake machine. The mesophase binder asphalt outlet of the second reactor is connected to the inlet of the third reactor via a pipeline through the mesophase binder asphalt buffer tank and the second heat exchanger. The mesophase binder asphalt buffer tank is also connected to the mesophase binder asphalt flake machine via a pipeline.

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