Mesophase pitch and coated pitch joint production device and preparation method

Abstract

The invention relates to the technical field of teapots, in particular to a joint production device and preparation method of mesophase pitch and coated pitch. The joint production device comprises a reaction kettle, a light oil receiving kettle, a separation kettle, a mesophase pitch kettle and a coated pitch kettle, and the reaction kettle, the light oil receiving kettle, the separation kettle, the mesophase pitch kettle and the coated pitch kettle are distributed on platforms with different heights. According to the present invention, the density difference between the anisotropic structure of the mesophase pitch and the isotropic structure of the coated pitch is utilized, the viscosity of the system is optimized by reasonably adjusting the light component of the raw material so as to achieve the efficient separation, and the light component of the raw material is utilized to adjust the viscosity of the system so as to achieve the complete separation purpose; meanwhile, due to joint production of anisotropic pitch and isotropic pitch, the problem of coking in the existing mesophase pitch production process is solved, so that an oxidation process is not needed in the coated pitch production process, and the coated pitch does not have a mesophase structure.

Description

Technical Field

[0001] The invention relates to the technical field of preparation of mesophase asphalt and coated asphalt, and in particular to a combined production device and preparation method of mesophase asphalt and coated asphalt. Background Art

[0002] Mesophase asphalt is an important precursor of advanced carbon materials, and can be used to prepare high-performance asphalt-based carbon fibers, high thermal conductivity carbon foams, high-performance C / C composites, etc. Mesophase asphalt can be divided into coal-based, oil-based, naphthalene-based, etc. according to the raw materials. Coal-based and oil-based raw materials are complex, and thermal polycondensation is generally used to prepare mesophase asphalt. However, as the reaction proceeds, the mesophase content gradually increases, the viscosity of the system increases, and it is very easy to coke, resulting in an increase in the softening point, which is not conducive to the rheology of the asphalt, resulting in subsequent difficulties in spinning or uneven foaming. Naphthalene-based mesophase asphalt generally adopts catalytic polymerization, but there are problems such as high process risk factor and difficulty in removing the catalyst.

[0003] The negative electrode material of lithium battery is mainly graphite. Since graphite itself has some structural defects that affect the battery cycle performance, a coating agent is generally used to wrap the graphite surface to improve the defects and thus improve the battery performance. Isotropic asphalt is an excellent graphite coating agent. It tends to be a hard carbon structure below 1000 degrees, which can improve the rate performance of lithium battery. Coated asphalt is generally required not to contain an intermediate phase structure. The intermediate phase spheres attached to the graphite surface will increase graphite defects, affect the intercalation of lithium ions, and thus affect the cycle performance.

[0004] At present, in order to suppress the formation of mesophase structure, the coated asphalt on the market generally adopts oxidation process to increase the softening point of asphalt. The asphalt oxidation process is a nationally eliminated process. In addition, the oxidation process has the characteristics of easy coking of pipelines. Based on the current process characteristics of mesophase asphalt and coated asphalt, it is necessary to improve the existing process. Therefore, it is urgent to design a combined production device and preparation method of mesophase asphalt and coated asphalt to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide a combined production device and preparation method for mesophase asphalt and coated asphalt, so as to overcome the shortcomings of the prior art and simultaneously prepare mesophase asphalt and coated asphalt for lithium battery negative electrode.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a device for the joint production of mesophase asphalt and coated asphalt, comprising a reactor, a light oil receiving reactor, a separation reactor, a mesophase asphalt reactor and a coated asphalt reactor, wherein the reactor, the light oil receiving reactor, the separation reactor, the mesophase asphalt reactor and the coated asphalt reactor are distributed on platforms at different heights and are connected by pipelines.

[0007] Preferably, the reactor is a main asphalt polymerization reactor, a light oil outlet is provided on the upper surface of the reactor, the light oil outlet of the reactor is connected to the light oil receiving reactor, and a polymerized asphalt outlet is provided directly below the reactor and is connected to the separation reactor below.

[0008] Preferably, a tee is provided below the light oil receiving kettle, one of the tee output ends of the light oil receiving kettle is connected to the separation kettle, and the other end is used as a by-product transfer device.

[0009] Preferably, the intermediate phase asphalt kettle is connected directly below the separation kettle, and the side outlet below the separation kettle is connected to the coating asphalt kettle.

[0010] Preferably, the material transportation from the reaction kettle to the separation kettle, from the light oil receiving kettle to the separation kettle, from the separation kettle to the mesophase asphalt kettle, and from the separation kettle to the coated asphalt kettle is all carried out by gravity.

[0011] Preferably, an online viscometer is arranged below the asphalt discharge port of the separation kettle.

[0012] Preferably, the mesophase asphalt kettle and the coated asphalt kettle are provided with a bottom-through pipeline or a vacuum device.

[0013] A method for jointly preparing mesophase asphalt and coated asphalt comprises the following steps:

[0014] S1: The materials in the reactor are polymerized to generate masterbatch. After sampling and analysis, it is confirmed that the mesophase content of the material is between 10% and 60%, and the softening point is between 140 and 220°C. The specific value is determined according to the results of the small test;

[0015] S2: The light oil produced in the S1 polymerization stage is received in a light oil receiving tank;

[0016] S3: When the masterbatch temperature in the reactor drops below 350°C, it is discharged into the separation reactor by gravity through the discharge port directly below;

[0017] S4: slowly put the light oil in the light oil receiving tank into the separation kettle, start the separation kettle for stirring, and the amount of light oil injected shall be based on the experimental results, generally 5%-30% of the total amount of materials;

[0018] S5: When the material system of the separation kettle is stable, the stirring is stopped and the separation kettle begins to settle and separate. The settling temperature is preferably 320-350°C and the settling time is preferably 5-10h;

[0019] S6: Separate the mesophase asphalt and isotropic asphalt in the kettle. Due to the difference in density, stratification will occur. The bottom is the mesophase asphalt, and the upper part is the coating asphalt (isotropic asphalt);

[0020] S7: After the sedimentation is completed, slowly open the bottom valve to slowly flow the mesophase asphalt at the bottom into the mesophase asphalt kettle. When the viscosity of the system changes significantly, close the bottom valve and the unloading of the mesophase asphalt is completed;

[0021] S8: Open the side valve of the separation kettle, pour all the upper liquid into the coating asphalt kettle, and close the valve;

[0022] S9: maintaining the material temperature in the mesophase asphalt reactor at 350-400° C., and further purifying the material by vacuum or inert gas purging to obtain a mesophase asphalt with a mesophase content of 100% and a softening point of 260-320° C.;

[0023] S10: Maintain the material temperature in the coated asphalt kettle at 300-400°C, and use vacuum or inert gas purging to recover the light components, so as to obtain coated asphalt without intermediate phase, and the softening point is close to that of the masterbatch of S1.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention adopts a polymerization process to generate a mother liquor containing 20-50% mesophase content, rather than increasing it to 100% mesophase asphalt in one step. This strategy makes full use of the density difference between the anisotropic structure of the mesophase asphalt and the isotropic structure of the coated asphalt, and optimizes the viscosity of the system by reasonably adjusting the light components of the raw materials, thereby achieving efficient separation, and adjusting the viscosity of the system using the light components of the raw materials themselves, thereby achieving the purpose of complete separation. At the same time, the present invention realizes the joint production of anisotropic asphalt and isotropic asphalt, solves the coking problem in the current mesophase asphalt production process, does not require an oxidation process in the production process of the coated asphalt, and does not have a mesophase structure, and the material transfer of the main product of the present invention is entirely completed by gravity, with small investment and easy industrialization. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic front view of the structure of the present invention. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] See also Figure 1 , the present invention is described in further detail:

[0028] Example 1

[0029] 1000kg of treated catalytic oil slurry was transported to the reactor, reacted at 400℃ and 2MPa for 5h, and purged with nitrogen to 350℃. The light oil in the purging process entered the light oil receiving tank after heat exchange. The masterbatch in the reactor was sampled and analyzed. The softening point of the masterbatch was 172℃ and the yield was 45%. The masterbatch was unloaded into the separation tank, the stirring of the separation tank was turned on, and 50kg of light oil in the light oil tank was slowly added. The stirring was continued to maintain the system temperature at 340℃. After stirring for half an hour, the stirring of the separation tank was turned off, and the settling began. The settling time was 6 hours. After the standing was completed, the bottom valve was opened, and the lower intermediate phase asphalt was slowly flowed into the intermediate phase asphalt kettle. When the viscosity of the system changes sharply, the bottom valve was closed. The side valve was opened, and the upper isotropic asphalt was slowly flowed into the coated asphalt kettle. When it is completely in, the side valve was closed. The mesophase asphalt kettle was evacuated at 380℃ for 3h and the pressure was -0.098MPa to obtain a mesophase asphalt with a content of 100%, a softening point of 296℃, and a total of 150kg. The coated asphalt kettle was evacuated at 340℃ for 2h and the pressure was -0.098MPa to obtain a coated asphalt with a softening point of 180℃ and a mesophase content of 0%, and a total of 275kg.

[0030] Comparison case:

[0031] In the above case, if 50kg of light oil is not added, under the same process, the softening point of the obtained mesophase asphalt is 302℃, the weight is 138kg, and the mesophase content is 100%. The softening point of the obtained coated asphalt is 183℃, the mesophase content is about 2%, and the total is 283kg. The coated asphalt obtained under this process condition has a mesophase structure and does not meet the quality requirements of the coated asphalt.

[0032] An embodiment provided by the present invention:

[0033] It includes a reaction kettle, a light oil receiving kettle, a separation kettle, an intermediate phase asphalt kettle and a coated asphalt kettle. The reaction kettle, the light oil receiving kettle, the separation kettle, the intermediate phase asphalt kettle and the coated asphalt kettle are distributed on platforms at different heights and are connected by pipelines.

[0034] Furthermore, the reactor is the main asphalt polymerization reactor, and a light oil outlet is provided on the upper surface of the reactor so that the light oil generated by the reaction can be recovered in time during the polymerization reaction. The light oil outlet of the reactor is connected to the light oil receiving reactor, and an outlet for polymerized asphalt is provided directly below the reactor, and is connected to the separation reactor below to avoid reflux or leakage caused by excessive pressure. An outlet for polymerized asphalt is provided directly below the reactor, through which the asphalt after polymerization is safely and efficiently introduced into the separation reactor below. Such a configuration design not only improves the convenience and safety of material transportation, but also lays a solid foundation for subsequent processing links (such as separation and refining), and improves the automation level and production efficiency of the entire production line.

[0035] Furthermore, a tee is set below the light oil receiving kettle. The design of the tee pipeline greatly enhances the flexibility and functionality of the system. One end of the tee output of the light oil receiving kettle is connected to the separation kettle, and the other end is used as a by-product transfer device, which is convenient for collecting and processing by-products generated during the reaction. This two-way flow design effectively reduces the retention of materials and reduces the risk of system blockage.

[0036] Furthermore, the intermediate phase asphalt kettle is connected directly below the separation kettle, and the side outlet below the separation kettle is connected to the coating asphalt kettle, so as to realize efficient transfer of materials after polymerization reaction. The separation kettle is designed to make full use of the density difference of the materials to realize efficient layer separation operation.

[0037] Furthermore, the material transportation from the reaction kettle to the separation kettle, the light oil receiving kettle to the separation kettle, the separation kettle to the intermediate phase asphalt kettle and the separation kettle to the coated asphalt kettle is all carried out by gravity, without the need for an asphalt pump, thereby reducing the risk of transportation, saving transportation equipment and reducing transportation costs.

[0038] Furthermore, an online viscometer is arranged below the asphalt discharge port of the separation kettle, which can be used as a basis for the discharge amount of the intermediate phase asphalt.

[0039] Furthermore, the mesophase asphalt kettle and the coated asphalt kettle are provided with bottom-through pipelines or vacuum devices for extracting light components, thereby achieving the purpose of purification.

[0040] A method for jointly preparing mesophase asphalt and coated asphalt comprises the following steps:

[0041] S1: The materials in the reactor are polymerized to generate masterbatch. After sampling and analysis, it is confirmed that the mesophase content of the material is between 10% and 60%, and the softening point is between 140 and 220°C. The specific value is determined according to the results of the small test;

[0042] S2: The light oil produced in the S1 polymerization stage is received in a light oil receiving tank;

[0043] S3: When the masterbatch temperature in the reactor drops below 350°C, it is discharged into the separation reactor by gravity through the discharge port directly below;

[0044] S4: slowly put the light oil in the light oil receiving tank into the separation kettle, start the separation kettle for stirring, and the amount of light oil injected shall be based on the experimental results, generally 5%-30% of the total amount of materials;

[0045] S5: When the material system of the separation kettle is stable, the stirring is stopped and the separation kettle begins to settle and separate. The settling temperature is preferably 320-350°C and the settling time is preferably 5-10h;

[0046] S6: Separate the mesophase asphalt and isotropic asphalt in the kettle. Due to the difference in density, stratification will occur. The bottom is the mesophase asphalt, and the upper part is the coating asphalt (isotropic asphalt);

[0047] S7: After the sedimentation is completed, slowly open the bottom valve to slowly flow the mesophase asphalt at the bottom into the mesophase asphalt kettle. When the viscosity of the system changes significantly, close the bottom valve and the unloading of the mesophase asphalt is completed;

[0048] S8: Open the side valve of the separation kettle, pour all the upper liquid into the coating asphalt kettle, and close the valve;

[0049] S9: maintaining the material temperature in the mesophase asphalt reactor at 350-400° C., and further purifying the material by vacuum or inert gas purging to obtain a mesophase asphalt with a mesophase content of 100% and a softening point of 260-320° C.;

[0050] S10: Maintain the material temperature in the coated asphalt kettle at 300-400°C, and use vacuum or inert gas purging to recover the light components, so as to obtain coated asphalt without intermediate phase, and the softening point is close to that of the masterbatch of S1.

[0051] Working principle: The reactor is the main asphalt polymerization reactor. It polymerizes the raw materials to form a masterbatch. By sampling and analyzing the materials in the reactor, key parameters such as the intermediate phase content and softening point are confirmed. During the polymerization reaction, the light oil produced is introduced into the light oil receiving reactor through the light oil outlet to ensure resource recovery and subsequent treatment. The bottom outlet of the reactor is directly connected to the separation kettle. After the reaction is completed, when the temperature drops below 350°C, the asphalt produced after polymerization is safely and efficiently unloaded into the separation kettle by gravity. In the separation kettle, due to the density difference, the material begins to settle after the temperature is raised and lightly stirred. At a suitable sedimentation temperature (generally 320-350°C), after 5 to 10 hours of sedimentation, the asphalt in the separation kettle will be stratified, and the upper layer is the coated asphalt (all the same The upper layer is the intermediate phase asphalt, and the lower layer is the intermediate phase asphalt. After the sedimentation is completed, the operator will slowly open the bottom valve of the separation kettle to allow the intermediate phase asphalt to flow into the intermediate phase asphalt kettle. After the system viscosity changes significantly, the valve will be closed to complete the unloading of the intermediate phase asphalt. Subsequently, the coated asphalt of the upper layer is transferred to the coated asphalt kettle through the side valve. The intermediate phase asphalt and the coated asphalt maintain a certain temperature range in their respective kettles, usually at 350-400℃ for vacuum or inert gas purging treatment. Through this method, light component impurities can be further removed, thereby improving the purity and performance of the intermediate phase asphalt and the coated asphalt, and achieving the final required product specifications: the intermediate phase asphalt content reaches 100%, and the softening point is at 260-320℃; at the same time, the coated asphalt can obtain a high-purity product without intermediate phase components.

[0052] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A combined production device for mesophase asphalt and coated asphalt, characterized in that: It includes a reaction kettle, a light oil receiving kettle, a separation kettle, an intermediate phase asphalt kettle and a coated asphalt kettle. The reaction kettle, the light oil receiving kettle, the separation kettle, the intermediate phase asphalt kettle and the coated asphalt kettle are distributed on platforms at different heights and are connected by pipelines.

2. The combined production device of mesophase asphalt and coated asphalt according to claim 1 is characterized in that: The reactor is a main asphalt polymerization reactor, and a light oil outlet is provided on the upper surface of the reactor, and the light oil outlet of the reactor is connected to the light oil receiving reactor. A polymerized asphalt outlet is provided directly below the reactor and is connected to the separation reactor below.

3. The combined production device of mesophase asphalt and coated asphalt according to claim 2, characterized in that: A tee is provided below the light oil receiving kettle, one end of the tee output of the light oil receiving kettle is connected to the separation kettle, and the other end is used as a by-product transfer device.

4. The combined production device of mesophase asphalt and coated asphalt according to claim 3 is characterized in that: The middle phase asphalt kettle is connected directly below the separation kettle, and the side outlet below the separation kettle is connected to the coating asphalt kettle.

5. The combined production device of mesophase asphalt and coated asphalt according to claim 4, characterized in that: The material transportation from the reaction kettle to the separation kettle, from the light oil receiving kettle to the separation kettle, from the separation kettle to the mesophase asphalt kettle, and from the separation kettle to the coated asphalt kettle is all carried out by gravity.

6. The combined production device of mesophase asphalt and coated asphalt according to claim 1, characterized in that: An online viscometer is arranged below the asphalt discharge port of the separation kettle.

7. The combined production device of mesophase asphalt and coated asphalt according to claim 6, characterized in that: The mesophase asphalt kettle and the coated asphalt kettle are provided with a bottom-through pipeline or a vacuum device.

8. A method for the combined preparation of mesophase asphalt and coated asphalt, using a combined production device for mesophase asphalt and coated asphalt according to any one of claims 1 to 7, comprising the following steps: S1: The materials in the reactor are polymerized to generate masterbatch. After sampling and analysis, it is confirmed that the mesophase content of the material is between 10% and 60%, and the softening point is between 140 and 220°C. The specific value is determined according to the results of the small test; S2: The light oil produced in the S1 polymerization stage is received in a light oil receiving tank; S3: When the masterbatch temperature in the reactor drops below 350°C, it is discharged into the separation reactor by gravity through the discharge port directly below; S4: slowly put the light oil in the light oil receiving tank into the separation kettle, start the separation kettle for stirring, and the amount of light oil injected shall be based on the experimental results, generally 5%-30% of the total amount of materials; S5: When the material system of the separation kettle is stable, the stirring is stopped and the separation kettle begins to settle and separate. The settling temperature is preferably 320-350°C and the settling time is preferably 5-10h; S6: Separate the mesophase asphalt and isotropic asphalt in the kettle. Due to the difference in density, stratification will occur. The bottom is the mesophase asphalt, and the upper part is the coating asphalt (isotropic asphalt); S7: After the sedimentation is completed, slowly open the bottom valve to slowly flow the mesophase asphalt at the bottom into the mesophase asphalt kettle. When the viscosity of the system changes significantly, close the bottom valve and the unloading of the mesophase asphalt is completed; S8: Open the side valve of the separation kettle, pour all the upper liquid into the coating asphalt kettle, and close the valve; S9: maintaining the material temperature in the mesophase asphalt reactor at 350-400° C., and further purifying the material by vacuum or inert gas purging to obtain a mesophase asphalt with a mesophase content of 100% and a softening point of 260-320° C.; S10: Maintain the material temperature in the coated asphalt kettle at 300-400°C, and use vacuum or inert gas purging to recover the light components, so as to obtain coated asphalt without intermediate phase, and the softening point is close to that of the masterbatch of S1.

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