阅读说明：本技术 一种制备中间相沥青的连续式循环聚合蒸馏反应系统 (Continuous type circulation polymerization distillation reaction system of preparation mesophase pitch ) 是由 孙海成 杜军伟 康延涛 李鹏飞 于 2021-10-26 设计创作，主要内容包括：本发明属于化工领域,具体公开了一种制备中间相沥青的连续式循环聚合蒸馏反应系统,包括：异向双螺杆输送挤出机、磁力驱动恒压搅拌器、静态混合器、静置密度分离器、一级异向双螺杆脱挥挤出机、二级异向双螺杆脱挥挤出机和真空过滤缓冲罐。本发明采用管道式连续化线生产方式,从启动设备加入原料开始,可以连续不断的进行生产,整个过程经历了高温高压聚合、轻重组分分离、真空蒸馏脱挥,每个工艺阶段都互不干涉,独立工作,从加入原料到成品产出,都无需停机操作,所有操作过程都由程序控制,实现了大规模工程化制备中间相沥青的生产工艺流程。本发明制备中间相沥青,提高了生产效率,降低了生产成本,并且提高了产品的性能稳定性与一致性。(The invention belongs to the field of chemical industry, and particularly discloses a continuous cyclic polymerization distillation reaction system for preparing mesophase pitch, which comprises: a counter-rotating double-screw conveying extruder, a magnetic drive constant-pressure stirrer, a static mixer, a standing density separator, a first-stage counter-rotating double-screw devolatilizing extruder, a second-stage counter-rotating double-screw devolatilizing extruder and a vacuum filtration buffer tank. The invention adopts a pipeline type continuous line production mode, can continuously produce from the start of adding raw materials by starting equipment, and the whole process is subjected to high-temperature high-pressure polymerization, light and heavy component separation and vacuum distillation devolatilization, each process stage is not interfered with each other and works independently, and the process from adding raw materials to producing finished products does not need to stop the operation, and all the operation processes are controlled by programs, thereby realizing the production process flow of preparing mesophase asphalt in large scale engineering. The invention prepares the mesophase pitch, improves the production efficiency, reduces the production cost and improves the performance stability and consistency of the product.)

1. A continuous loop polymerization distillation reaction system for preparing mesophase pitch, comprising: a counter-rotating double-screw conveying extruder (1), a magnetic drive constant-pressure stirrer (2), a static mixer (3), a standing density separator (4), a first-stage counter-rotating double-screw devolatilization extruder (5), a second-stage counter-rotating double-screw devolatilization extruder (6) and a vacuum filtration buffer tank (7);

an upper inlet of the magnetic drive constant-pressure stirrer (2) is communicated with an outlet of the counter-rotating double-screw conveying extruder (1), and a lower outlet of the magnetic drive constant-pressure stirrer (2) is communicated with an inlet of the static mixer (3); an outlet of the static mixer (3) is connected with an inlet of the counter-rotating twin-screw conveying extruder (1); the other outlet is connected with the upper inlet of the static density separator (4); an outlet at the lower part of the standing density separator (4) is connected with the other inlet of the counter-rotating double-screw conveying extruder (1); the other outlet of the standing density separator (4) is connected with the inlet of a first-stage counter-rotating twin-screw devolatilization extruder (5); the outlet of the first-stage counter-rotating twin-screw devolatilization extruder (5) is communicated with the inlet of the second-stage counter-rotating twin-screw devolatilization extruder (6); one outlet of the second-stage counter-rotating twin-screw devolatilization extruder (6) is an asphalt outlet (67), and the other outlet is connected with the inlet of the first-stage counter-rotating twin-screw devolatilization extruder (5); the vacuum filtration buffer tank (7) is respectively connected with the first-stage counter-rotating twin-screw devolatilization extruder (5) and the second-stage counter-rotating twin-screw devolatilization extruder (6).

2. A continuous cyclic polymerization distillation reaction system for preparing mesophase pitch according to claim 1, wherein the counter-rotating twin screw conveying extruder (1) comprises a magnetically driven counter-rotating twin screw gearbox (11), a conveying cylinder (12), a small lead conveying screw (13), a first forward static mixing module (14), a first reverse static mixing module (15), a conveying extruder feed pipe (16), a conveying extruder circulating feed pipe (17), a first three-way solenoid valve (18) and a raw material feed pipe (19);

the counter-rotating double-screw conveying extruder (1) is divided into a power end and a working end, wherein the power end is a magnetic force driving counter-rotating double-shaft gear box (11), and the working end is a conveying charging barrel (12); a first-stage small-lead devolatilization screw (13) which can be driven by a power end is arranged in the conveying material cylinder (12); a first forward static mixing module (14) and a first reverse static mixing module (15) are nested inside the delivery cylinder (12); the feeding pipe (16) of the conveying extruder and the circulating feeding pipe (17) of the conveying extruder are horizontally and symmetrically arranged at the inlet of the front end of the conveying charging barrel (12); the raw material feeding pipe (19) is communicated with the feeding pipe (16) of the conveying extruder through a first three-way electromagnetic valve (18).

3. The continuous loop polymerization distillation reaction system for preparing mesophase pitch according to claim 2, wherein the magnetically-driven constant-pressure stirrer (2) comprises a stirring cylinder (21), a paddle-type stirring blade (22), an electromagnetic opening regulating valve (24), a magnetically-driven disk (25) and an exhaust port (26);

the top of the stirring cylinder (21) is provided with a magnetic driving disc (25) and an exhaust port (26); the blade type stirring paddle (22) is arranged in the stirring barrel (21) and is connected with a magnetic driving disk (25) at the top; an electromagnetic opening degree regulating valve (24) is arranged on an exhaust port (26) of the stirring cylinder (21).

4. A continuous loop polymerization distillation reaction system for producing mesophase pitch according to claim 3, wherein said static mixer (3) comprises a mixing cylinder (31), a second forward static mixing module (32), a second reverse static mixing module (33), a static mixer discharge pipe (34) and a second three-way solenoid valve (35);

the mixing material barrel (31) is communicated with a second three-way electromagnetic valve (35) through a static mixer discharging pipe (34); the second three-way electromagnetic valve (35) is provided with two passages, and the outlet of the static mixer (3) can be respectively and independently communicated with the counter-rotating double-screw conveying extruder (1) and the standing density separator (4) by controlling the second three-way electromagnetic valve (35); the second forward static mixing modules (32) and the second reverse static mixing modules (33) are alternately nested inside the mixing cylinder (31).

5. A continuous cyclic polymerization distillation reaction system for preparing mesophase pitch according to claim 4, wherein the still standing density separator (4) comprises a separator feeding pipe (41), a weight-loss type mass metering scale (42), a volumetric metering delivery pump (43), a third three-way solenoid valve (44), a heavy component delivery pipe (45) and a light component delivery pipe (46);

the main structure of the standing density separator (4) is arranged on a weight-loss type mass metering scale (42), the top of the main structure of the standing density separator (4) is provided with a separator feeding pipe (41), and the outlet at the bottom of the main structure of the standing density separator (4) is connected with the inlet of a volumetric metering conveying pump (43); the outlet of the volumetric metering delivery pump (43) is connected with a third three-way electromagnetic valve (44); the third three-way electromagnetic valve (44) is provided with two passages, and the outlet of the volumetric metering delivery pump (43) can be respectively and independently communicated with the heavy component delivery pipe (45) and the light component delivery pipe (46) by controlling the third three-way electromagnetic valve (44); the heavy component conveying pipe (45) is communicated with the first-stage counter-rotating twin-screw devolatilization extruder (5); the light component conveying pipe (46) is communicated with the counter-rotating twin-screw conveying extruder (1) through a first three-way electromagnetic valve (18) and a conveying extruder feeding pipe (16).

6. The continuous cyclic polymerization distillation reaction system for preparing mesophase pitch according to claim 5, wherein the first-stage counter-rotating twin-screw devolatilization extruder (5) comprises a first magnetically-driven counter-rotating twin-screw gearbox (51), a first-stage devolatilization barrel (52), a first-stage large-lead devolatilization screw (53), a first-stage devolatilization extruder feed pipe (54), a first-stage devolatilization extruder discharge pipe (55), a fourth three-way solenoid valve (56), and a first-stage devolatilization vacuum pump (57);

the first-stage counter-rotating twin-screw devolatilization extruder (5) is divided into a power end and a working end, wherein the power end is a first magnetic force driven counter-rotating twin-screw gear box (51), and the working end is a first-stage devolatilization charging barrel (52); a primary large-lead devolatilization screw (53) which can be driven by a power end is arranged in the primary devolatilization cylinder (52); the feeding pipe (54) of the primary devolatilization extruder is positioned at the inlet of the front end of the primary devolatilization charging barrel (52) and is communicated with a fourth three-way electromagnetic valve (56); the discharge pipe (55) of the first-stage devolatilization extruder is communicated with the inlet of the second-stage counter-rotating twin-screw devolatilization extruder (6).

7. The continuous cyclic polymerization distillation reaction system for preparing mesophase pitch according to claim 6, wherein the two-stage counter-rotating twin-screw devolatilization extruder (6) comprises a second magnetically-driven counter-rotating twin-screw gear box (61), a two-stage devolatilization cylinder (62), a two-stage large-lead devolatilization screw (63), a two-stage devolatilization extruder discharge pipe (64), a fifth three-way solenoid valve (65), a devolatilization extruder circulating flow pipe (66), a pitch outlet (67) and a two-stage devolatilization vacuum pumping pipe (68);

the two-stage counter-rotating twin-screw devolatilization extruder (6) is divided into a power end and a working end, wherein the power end is a second magnetic force driven counter-rotating twin-screw gear box (61), and the working end is a two-stage devolatilization charging barrel (62); a secondary large-lead devolatilization screw (63) which can be driven by a power end is arranged in the secondary devolatilization cylinder (62); the discharge pipe (64) of the secondary devolatilization extruder is positioned at the outlet of the tail end of the secondary devolatilization charging barrel (62) and is communicated with a fifth three-way electromagnetic valve (65); the fifth three-way electromagnetic valve (65) is provided with two passages, and the outlet of the discharge pipe (64) of the secondary devolatilization extruder can be respectively and independently communicated with the circulating flow pipe (66) of the devolatilization extruder and the asphalt outlet (67) by controlling the fifth three-way electromagnetic valve (65); a circulating flow pipe (66) of the devolatilization extruder is communicated with the first-stage counter-rotating twin-screw devolatilization extruder (5) through a fourth three-way electromagnetic valve (56) and a feeding pipe (54) of the first-stage devolatilization extruder.

8. The continuous cyclic polymerization distillation reaction system for preparing mesophase pitch according to claim 7, wherein said vacuum filtration buffer tank (7) comprises a vacuum filtration buffer tank main body and a three-stage devolatilization vacuum pumping port (71); the vacuum filtering buffer tank (7) is communicated with the primary devolatilization barrel (52) through a primary devolatilization vacuum-pumping tube (57); the vacuum filtering buffer tank (7) is communicated with the secondary devolatilization barrel (62) through a secondary devolatilization vacuum-pumping tube (68); the three-stage devolatilization vacuumizing port (71) is connected to a vacuum device.

9. The continuous circulation polymerization distillation reaction system for preparing mesophase pitch according to claim 8, wherein the closed loop among the counter-rotating twin-screw conveying extruder (1), the magnetic-driven constant-pressure stirrer (2) and the static mixer (3) is a raw material polymerization circulation path (I); the second three-way electromagnetic valve (35) is connected with a fourth three-way electromagnetic valve (56) through a separator feeding pipe (41), a standing density separator (4), a volumetric metering delivery pump (43), a third three-way electromagnetic valve (44) and a light component delivery pipe (46) to form a raw material light and heavy component separation path (II); a closed loop formed by the first-stage counter-rotating twin-screw devolatilization extruder (5) and the second-stage counter-rotating twin-screw devolatilization extruder (6) is a heavy component raw material distillation devolatilization path (III); the first three-way electromagnetic valve (18) is connected with a third three-way electromagnetic valve (44) through a light component conveying pipe (46) to form a light component raw material repolymerization path (IV).

10. The continuous cyclic polymerization distillation reaction system for preparing mesophase pitch according to claim 1, wherein the counter-rotating twin-screw conveying extruder (1), the static mixer (3), the primary counter-rotating twin-screw devolatilization extruder (5) and the secondary counter-rotating twin-screw devolatilization extruder (6) are in a long cylindrical cavity structure; the magnetic drive constant-pressure stirrer (2) and the standing density separator (4) are cylindrical cavity structures.

Technical Field

The invention belongs to the field of chemical industry, and particularly relates to a continuous cyclic polymerization distillation reaction system for preparing mesophase pitch.

Background

The mesophase pitch-based carbon fiber is a high-performance carbon fiber, shows superiority in modulus and performance due to high orientation of the molecular structure thereof, and has great application prospects in the fields of national defense industry, aerospace, advanced science and technology, daily life and the like.

Mesophase pitch-based carbon fibers are generally produced from optically anisotropic mesophase pitch using coal pitch, petroleum pitch or other pitches as raw materials. The mesophase pitch is a mixture composed of a plurality of flat disc-shaped fused ring aromatic hydrocarbons with the relative molecular mass of 370-2000, wherein the useful part of the mesophase pitch presents an optically anisotropic turbid fluid state, is in a liquid state and has the characteristics of crystal optical anisotropy, and is called liquid crystal in crystallography and called mesophase in facies. In the process of preparing the mesophase pitch, the mesophase pitch is subjected to the processes of high-pressure polymerization, component purification, vacuum distillation and the like.

At present, in the traditional mesophase pitch preparation, reaction kettles are adopted for preparation, and the whole process belongs to an intermittent production process no matter single reaction kettle is adopted for independent preparation or a plurality of reaction kettles are adopted for multistage series preparation, so that the production time is long, the labor intensity is high, the yield is low, the production cost is high, and the stability of batches is poor. In the traditional intermediate phase asphalt preparation process, the processes such as high-pressure polymerization, vacuum distillation and the like cannot be carried out in a circulating reaction manner, the chemical reaction cannot be carried out completely, non-intermediate phase components inevitably exist, meanwhile, the generated non-intermediate phase products cannot be found and removed in real time in the traditional process, and the impurities are mixed and flow into the final stage of the product, so that the final intermediate phase asphalt components are impure and the quality is not high. Therefore, a novel device for preparing mesophase pitch is needed, which not only can produce high-performance and high-purity mesophase pitch for spinning, but also can realize large-scale engineering continuous preparation, reduce the production cost and improve the production efficiency.

Disclosure of Invention

The invention aims to provide a continuous cyclic polymerization distillation reaction system for preparing mesophase pitch, which solves the problems of low production efficiency, impure mesophase pitch components and low quality in the prior art when preparing the mesophase pitch.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a continuous cyclic polymerization distillation reaction system for preparing mesophase pitch, which comprises: a counter-rotating double-screw conveying extruder, a magnetic drive constant-pressure stirrer, a static mixer, a standing density separator, a first-stage counter-rotating double-screw devolatilizing extruder, a second-stage counter-rotating double-screw devolatilizing extruder and a vacuum filtration buffer tank;

an upper inlet of the magnetic force driving constant-pressure stirrer is communicated with an outlet of the counter-rotating double-screw conveying extruder, and a lower outlet of the magnetic force driving constant-pressure stirrer is communicated with an inlet of the static mixer; one outlet of the static mixer is connected with one inlet of the counter-rotating double-screw conveying extruder; the other outlet is connected with the upper inlet of the static density separator; an outlet at the lower part of the standing density separator is connected with the other inlet of the counter-rotating double-screw conveying extruder; the other outlet of the standing density separator is connected with the inlet of the first-stage counter-rotating twin-screw devolatilization extruder; the outlet of the first-stage counter-rotating twin-screw devolatilization extruder is communicated with the inlet of the second-stage counter-rotating twin-screw devolatilization extruder; one outlet of the second-stage counter-rotating twin-screw devolatilization extruder is an asphalt outlet, and the other outlet of the second-stage counter-rotating twin-screw devolatilization extruder is connected with the inlet of the first-stage counter-rotating twin-screw devolatilization extruder; the vacuum filtration buffer tank is respectively connected with the first-stage counter-rotating twin-screw devolatilization extruder and the second-stage counter-rotating twin-screw devolatilization extruder.

Furthermore, the counter-rotating twin-screw conveying extruder comprises a magnetic drive counter-rotating twin-screw gear box, a conveying charging barrel, a small-lead conveying screw, a first forward static mixing module, a first reverse static mixing module, a conveying extruder feeding pipe, a conveying extruder circulating feeding pipe, a first three-way electromagnetic valve and a raw material feeding pipe;

the counter-rotating double-screw conveying extruder is divided into a power end and a working end, wherein the power end is a magnetic force driving counter-rotating double-shaft gear box, and the working end is a conveying charging barrel; a first-stage small-lead devolatilization screw rod capable of being driven by a power end is arranged in the conveying charging barrel; the first forward static mixing module and the first reverse static mixing module are nested in the conveying material barrel; the feeding pipe of the conveying extruder and the circulating feeding pipe of the conveying extruder are horizontally and symmetrically arranged at the inlet of the front end of the conveying charging barrel; the raw material feeding pipe is communicated with the feeding pipe of the conveying extruder through a first three-way electromagnetic valve.

Furthermore, the magnetic drive constant-pressure stirrer comprises a stirring material barrel, a blade type stirring paddle, an electromagnetic opening degree regulating valve, a magnetic drive disk and an exhaust port;

the top of the stirring cylinder is provided with a magnetic driving disc and an exhaust port; the blade type stirring paddle is arranged in the stirring material barrel and is connected with the magnetic driving disk at the top; an electromagnetic opening degree regulating valve is arranged on the exhaust port of the stirring material cylinder.

Further, the static mixer comprises a mixing material barrel, a second forward static mixing module, a second reverse static mixing module, a static mixer discharging pipe and a second three-way electromagnetic valve;

the mixing material barrel is communicated with a second three-way electromagnetic valve through a discharging pipe of the static mixer; the second three-way electromagnetic valve is provided with two passages, and the outlet of the static mixer can be respectively and independently communicated with the counter-rotating double-screw conveying extruder and the standing density separator by controlling the second three-way electromagnetic valve; the second forward static mixing modules and the second reverse static mixing modules are alternately and sequentially nested and installed in the mixing barrel.

Further, the standing density separator comprises a separator feeding pipe, a weight-loss type mass metering scale, a volumetric metering delivery pump, a third three-way electromagnetic valve, a heavy component delivery pipe and a light component delivery pipe;

the main structure of the standing density separator is arranged on a weight-loss type mass metering scale, the top of the main structure of the standing density separator is a separator feeding pipe, and an outlet at the bottom of the main structure of the standing density separator is connected with an inlet of a volumetric metering conveying pump; the outlet of the volumetric metering delivery pump is connected with a third three-way electromagnetic valve; the third three-way electromagnetic valve is provided with two passages, and the outlet of the volumetric metering delivery pump can be respectively and independently communicated with the heavy component delivery pipe and the light component delivery pipe by controlling the third three-way electromagnetic valve; the heavy component conveying pipe is communicated with the first-stage counter-rotating double-screw devolatilization extruder; the light component conveying pipe is communicated with the counter-rotating double-screw conveying extruder through a first three-way electromagnetic valve and a conveying extruder feeding pipe.

Further, the first-stage counter-rotating twin-screw devolatilization extruder comprises a first magnetic force driving counter-rotating twin-screw gear box, a first-stage devolatilization material cylinder, a first-stage large-lead devolatilization screw, a first-stage devolatilization extruder feeding pipe, a first-stage devolatilization extruder discharging pipe, a fourth three-way electromagnetic valve and a first-stage devolatilization vacuumizing pipe;

the first-stage counter-rotating double-screw devolatilization extruder is divided into a power end and a working end, wherein the power end is a first magnetic force driven counter-rotating double-shaft gear box, and the working end is a first-stage devolatilization barrel; a primary large-lead devolatilization screw rod which can be driven by a power end is arranged in the primary devolatilization barrel; the feeding pipe of the primary devolatilization extruder is positioned at the inlet of the front end of the primary devolatilization charging barrel and is communicated with a fourth three-way electromagnetic valve; the discharge pipe of the first-stage devolatilization extruder is communicated with the inlet of the second-stage counter-rotating twin-screw devolatilization extruder.

Further, the second-stage counter-rotating twin-screw devolatilization extruder comprises a second magnetic force driving counter-rotating twin-screw gear box, a second-stage devolatilization charging barrel, a second-stage large-lead devolatilization screw, a second-stage devolatilization extruder discharging pipe, a fifth three-way electromagnetic valve, a devolatilization extruder circulating flow pipe, an asphalt outlet and a second-stage devolatilization vacuumizing pipe;

the two-stage counter-rotating twin-screw devolatilization extruder is divided into a power end and a working end, wherein the power end is a second magnetic force driven counter-rotating double-shaft gear box, and the working end is a two-stage devolatilization barrel; a secondary large-lead devolatilization screw rod which can be driven by a power end is arranged in the secondary devolatilization cylinder; the discharge pipe of the secondary devolatilization extruder is positioned at the outlet of the tail end of the secondary devolatilization charging barrel and is communicated with a fifth three-way electromagnetic valve; the fifth three-way electromagnetic valve is provided with two passages, and the outlet of the discharge pipe of the secondary devolatilization extruder can be respectively and independently communicated with the circulating flow pipe of the devolatilization extruder and the asphalt outlet by controlling the fifth three-way electromagnetic valve; the devolatilization extruder circulating flow pipe is communicated with the first-stage counter-rotating double-screw devolatilization extruder through a fourth three-way electromagnetic valve and a first-stage devolatilization extruder feed pipe.

Further, the vacuum filtration buffer tank comprises a vacuum filtration buffer tank main body and a three-stage devolatilization vacuumizing port; the vacuum filtration buffer tank is communicated with the primary devolatilization barrel through a primary devolatilization vacuumizing tube; the vacuum filtration buffer tank is communicated with the secondary devolatilization barrel through a secondary devolatilization vacuumizing tube; the three-stage devolatilization vacuum-pumping port is connected to vacuum equipment.

Furthermore, a closed loop among the counter-rotating twin-screw conveying extruder, the magnetic drive constant-pressure stirrer and the static mixer is a raw material polymerization circulation path; the second three-way electromagnetic valve is connected with a fourth three-way electromagnetic valve through a separator feeding pipe, a standing density separator, a volumetric metering delivery pump, a third three-way electromagnetic valve and a light component delivery pipe to form a raw material light and heavy component separation path; a closed loop formed by the first-stage counter-rotating double-screw devolatilization extruder and the second-stage counter-rotating double-screw devolatilization extruder is a heavy component raw material distillation devolatilization path; the first three-way electromagnetic valve is connected with a third three-way electromagnetic valve through a light component conveying pipe to form a light component raw material repolymerization path.

Further, the counter-rotating twin-screw conveying extruder, the static mixer, the first-stage counter-rotating twin-screw devolatilization extruder and the second-stage counter-rotating twin-screw devolatilization extruder are of long cylinder cavity structures; the magnetic drive constant-pressure stirrer and the standing density separator are of cylindrical cavity structures.

Compared with the prior art, the invention has at least the following beneficial effects:

1. the invention adopts a pipeline type continuous production mode, can continuously produce after starting equipment to add raw materials, and the whole process is subjected to high-temperature high-pressure polymerization, light and heavy component separation and vacuum distillation devolatilization, each process stage is not interfered with each other and works independently, and the process from adding raw materials to producing finished products does not need to stop the machine, all the operation processes are controlled by programs, thereby realizing the production process flow of large-scale engineering preparation of mesophase pitch. The invention can improve the production efficiency, reduce the production cost and improve the performance stability and consistency of the product.

2. The polymerization distillation reaction system of the invention adds a component separation process between the high-temperature high-pressure polymerization and vacuum distillation devolatilization processes. Since the raw materials for preparing the mesophase pitch are mixtures, the molecular weight of the mixtures varies from 200 to 2000, and in the high-temperature polymerization stage, the mixtures undergo polycondensation to produce mesophase pitch starting products, and other derivatives of non-mesophase pitches are produced, and the densities are different due to the difference between the molecular weights and the molecular structures. The invention adds a component separation process, removes other mixtures outside the density range of the mesophase pitch, ensures that the content of the mesophase of the materials entering the vacuum distillation devolatilization process is highest, and finally, the quality and the performance of the mesophase pitch produced by distillation devolatilization are optimal.

3. The polymerization distillation reaction system separates the high-temperature high-pressure polymerization process from the vacuum distillation devolatilization process, and each process can form a circular flow production line, so that the chemical reaction is carried out in the flow, the mixing of the components of the raw materials is promoted, the reaction contact area is increased, and the process parameters of the materials such as the temperature, the pressure and the like at all positions of the equipment are more uniform and consistent in the flow process. The former improves the chemical reaction rate of each procedure and reduces the production period, and the latter improves the quality and performance of the product.

The method adopts a circulating flow reaction mode, controls the reaction time by adjusting the cycle times to produce mesophase pitch with different components, particularly adopts a large-lead screw extruder to carry out repeated circulating devolatilization in a vacuum distillation devolatilization stage, forms a millimeter-sized melt film on the surface of a screw by materials, and has better devolatilization effect than that of the traditional reaction kettle under vacuum. The final produced mesophase pitch is necessarily of higher quality.

4. The polymerization distillation reaction system adopts a sectional type working process, separates the polymerization process from the distillation process, and the polymerization process and the distillation process react in different equipment without mutual influence, any impurities, gel and harmful substances generated in the high-temperature polymerization stage are precipitated and adhered in the polymerization reaction equipment and cannot flow into the subsequent vacuum distillation devolatilization (rectification purification) process, so that the influence on a final product is avoided, and the final quality of a mesophase pitch finished product is improved.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic diagram of a continuous cyclic polymerization distillation reaction system for producing mesophase pitch.

Reference numerals: 1. a counter-rotating twin-screw conveying extruder; 11. the magnetic force drives the counter-rotating double-shaft gear box; 12. a conveying barrel; 13. a small lead conveying screw; 14. a first forward static mixing module; 15. a first reverse static mixing module; 16. a feed pipe of a conveying extruder; 17. a circulating feeding pipe of the conveying extruder; 18. a first three-way solenoid valve; 19. a raw material feeding pipe;

2. magnetically driving the constant-pressure stirrer; 21. stirring the charging barrel; 22. a blade type stirring paddle; 23. an electric contact pressure gauge; 24. an electromagnetic opening degree adjusting valve; 25. a magnetic drive disk; 26. an exhaust port;

3. a static mixer; 31. a mixing barrel; 32. a second forward static mixing module; 33. a second reverse static mixing module; 34. a static mixer discharge pipe; 35. a second three-way solenoid valve;

4. standing a density separator; 41. a separator feed tube; 42. a weight loss type mass scale; 43. a positive displacement metering delivery pump; 44. a third three-way solenoid valve; 45. a heavy component delivery pipe; 46. a light component conveying pipe;

5. a first-stage counter-rotating twin-screw devolatilization extruder; 51. the first magnetic force drives the counter-rotating double-shaft gearbox; 52. a primary devolatilization barrel; 53. a first-stage large-lead devolatilization screw; 54. a feeding pipe of a first-stage devolatilization extruder; 55. a discharge pipe of the primary devolatilization extruder; 56. a fourth three-way solenoid valve; 57. a first-stage devolatilization vacuum pumping tube; 58. a first-stage vacuum pressure gauge;

6. a second-stage counter-rotating twin-screw devolatilization extruder; 61. the second magnetic force drives the counter-rotating double-shaft gearbox; 62. a secondary devolatilization barrel; 63. a secondary large-lead devolatilization screw; 64. a discharge pipe of the secondary devolatilization extruder; 65. a fifth three-way solenoid valve; 66. circulating flow pipes of the devolatilization extruder; 67. -a bitumen discharge outlet; 68. a secondary devolatilization vacuum pumping tube; 69. a second-level vacuum pressure gauge;

7. a vacuum filtration buffer tank; 71. a three-stage devolatilization vacuumizing port;

i, a raw material polymerization circulation path; II, separating a light component and a heavy component of the raw material; III, carrying out distillation devolatilization on the heavy component raw material; IV, re-polymerizing the light component raw materials.

Detailed Description

The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings. It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

The following detailed description is exemplary in nature and is intended to provide further details of the invention. Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention.

As shown in FIG. 1, the present invention provides a continuous cyclic polymerization distillation reaction system for preparing mesophase pitch, comprising: a counter-rotating double-screw conveying extruder 1, a magnetic drive constant-pressure stirrer 2, a static mixer 3, a standing density separator 4, a first-stage counter-rotating double-screw devolatilizing extruder 5, a second-stage counter-rotating double-screw devolatilizing extruder 6 and a vacuum filtration buffer tank 7.

The counter-rotating twin-screw conveying extruder 1 comprises a magnetic drive counter-rotating twin-screw gear box 11, a conveying cylinder 12, a small-lead conveying screw 13, a first forward static mixing module 14, a first reverse static mixing module 15, a conveying extruder feeding pipe 16, a conveying extruder circulating feeding pipe 17, a first three-way electromagnetic valve 18 and a raw material feeding pipe 19.

The counter-rotating double-screw conveying extruder 1 is of a long cylinder cavity structure and is divided into a power end and a working end, wherein the power end is a magnetic force driven counter-rotating double-shaft gear box 11, and the working end is a conveying charging barrel 12. The first forward static mixing module 14 and the first reverse static mixing module 15 are modular, cylindrical structural units that are nested inside the transport cartridge 12. A first-stage small-lead devolatilization screw 13 which can be driven by a power end is installed inside the conveying cylinder 12; the small-lead conveying screw 13 is a group of small-lead screw combinations which are meshed with each other and rotate in different directions, and the small-lead conveying screw has the function of pushing the raw materials to advance and providing power for conveying the raw materials. A conveying extruder feed pipe 16 and a conveying extruder circulating feed pipe 17 are horizontally and symmetrically arranged at the front end inlet of the conveying barrel 12. The feedstock feed line 19 is in communication with the conveying extruder feed line 16 via a first three-way solenoid valve 18.

The magnetic drive constant-pressure stirrer 2 comprises a stirring material cylinder 21, a blade type stirring paddle 22, an electric contact pressure gauge 23, an electromagnetic opening degree regulating valve 24, a magnetic drive disk 25 and an exhaust port 26.

The magnetic drive constant-pressure stirrer 2 is of a cylindrical cavity structure, and the top of the stirring cylinder 21 is provided with a magnetic drive disk 25 and an exhaust port 26; the blade type stirring paddle 22 is arranged in the stirring barrel 21 and is connected with a magnetic driving disk 25 at the top; the stirring part of the blade type stirring paddle 22 is a structure that a plurality of groups of propelling blades are uniformly distributed and arranged in the vertical direction. An electromagnetic opening degree adjusting valve 24 is provided at an exhaust port 26 of the stirring cylinder 21, an electric contact pressure gauge 23 is further provided at the stirring cylinder 21, and the opening and closing state of the electromagnetic opening degree adjusting valve 24 is controlled by a set pressure value of the electric contact pressure gauge 23, so that the pressure in the magnetically-driven constant pressure stirrer 2 is maintained at a constant value. The outlet of the electromagnetic opening degree regulating valve 24 is communicated with an exhaust port 26.

The static mixer 3 comprises a mixing cylinder 31, a second forward static mixing module 32, a second reverse static mixing module 33, a static mixer outlet pipe 34 and a second three-way solenoid valve 35.

The static mixer 3 is a long cylinder cavity structure, and the mixing cylinder 31 is communicated with a second three-way electromagnetic valve 35 through a discharge pipe 34 of the static mixer. The second three-way electromagnetic valve 35 has two passages, and the outlet of the static mixer 3 can be separately communicated with the counter-rotating twin-screw conveying extruder 1 and the static density separator 4 by controlling the second three-way electromagnetic valve 35. The second forward static mixing modules 32 and the second reverse static mixing modules 33 are modular cylindrical structural units, alternately nested one inside the mixing barrel 31.

The standing density separator 4 comprises a separator feed pipe 41, a weight-loss mass scale 42, a volumetric metering delivery pump 43, a third three-way solenoid valve 44, a heavy component delivery pipe 45 and a light component delivery pipe 46.

The main structure of the standing density separator 4 is a cylindrical cavity structure, the main structure is arranged on a weightless mass metering scale 42, the top of the structural arrangement of the standing density separator 4 is a separator feeding pipe 41, and the bottom outlet of the structural arrangement of the standing density separator 4 is communicated with the inlet of a volumetric metering conveying pump 43. The outlet of the volumetric metering pump 43 communicates with a third three-way solenoid valve 44. The third three-way solenoid valve 44 has two passages, and the outlet of the volumetric delivery pump 43 can be independently communicated with the heavy component delivery pipe 45 and the light component delivery pipe 46 by controlling the third three-way solenoid valve 44. The heavy component conveying pipe 45 is communicated with the first-stage counter-rotating twin-screw devolatilization extruder 5 through a fourth three-way electromagnetic valve 56 and a first-stage devolatilization extruder feeding pipe 54. The light component conveying pipe 46 is communicated with the counter-rotating twin-screw conveying extruder 1 through the first three-way electromagnetic valve 18 and the conveying extruder feeding pipe 16.

The weight loss type mass scale 42 is a device for obtaining the mass flow rate of the raw material per unit time by measuring the mass data lost by the static density separator 4 per unit time. The volumetric metering delivery pump 43 is a metering delivery device in which the volume of material delivered per unit time is kept constant.

The first-stage counter-rotating twin-screw devolatilization extruder 5 comprises a first magnetic drive counter-rotating twin-screw gear box 51, a first-stage devolatilization material cylinder 52, a first-stage large-lead devolatilization screw 53, a first-stage devolatilization extruder feeding pipe 54, a first-stage devolatilization extruder discharging pipe 55, a fourth three-way electromagnetic valve 56, a first-stage devolatilization vacuumizing pipe 57 and a first-stage vacuum pressure gauge 58.

The first-stage counter-rotating twin-screw devolatilization extruder 5 is of a long cylinder cavity structure and is divided into a power end and a working end, wherein the power end is a first magnetic force driven counter-rotating twin-shaft gear box 51, and the working end is a first-stage devolatilization cylinder 52. The one-stage large-lead devolatilization screw 53 driven by a power end is a group of large-lead screw combinations which are meshed with each other and rotate in different directions, is arranged in the one-stage devolatilization material cylinder 52, and has the function of pushing the raw material to move forward and simultaneously forming a millimeter-grade film on the surface of the screw by the raw material, so that the volatile component in the screw can quickly escape. The primary devolatilization extruder feed tube 54 is located at the inlet at the front end of the primary devolatilization barrel 52 and is in communication with a fourth three-way solenoid valve 56. The discharge pipe 55 of the first-stage devolatilization extruder is communicated with the inlet of the second-stage counter-rotating twin-screw devolatilization extruder 6. A primary devolatilization vacuum pipe 57 is arranged at the middle section of the primary devolatilization barrel 52, and a primary vacuum pressure gauge 58 is arranged on the primary devolatilization vacuum pipe.

The second-stage counter-rotating twin-screw devolatilization extruder 6 comprises a second magnetic force driven counter-rotating twin-screw gear box 61, a second-stage devolatilization charging barrel 62, a second-stage large-lead devolatilization screw 63, a second-stage devolatilization extruder discharging pipe 64, a fifth three-way electromagnetic valve 65, a devolatilization extruder circulating flow pipe 66, an asphalt outlet 67, a second-stage devolatilization vacuum pumping pipe 68 and a second-stage vacuum pressure gauge 69.

The second-stage counter-rotating twin-screw devolatilization extruder 6 is of a long cylindrical cavity structure and is divided into a power end and a working end, wherein the power end is a second magnetic force driven counter-rotating twin-screw gear box 61, and the working end is a second-stage devolatilization barrel 62. The two-stage large-lead devolatilization screw 63 driven by a power end is a group of large-lead screw combinations which are meshed with each other and rotate in different directions, is arranged inside the two-stage devolatilization material barrel 62, and has the function of pushing the raw material to advance and simultaneously forming a millimeter-grade film on the surface of the screw by the raw material, so that the volatile component inside the screw can quickly escape. The discharge pipe 64 of the secondary devolatilization extruder is positioned at the outlet of the tail end of the secondary devolatilization barrel 62 and is communicated with a fifth three-way electromagnetic valve 65. The fifth three-way solenoid valve 65 has two passages, and the outlet of the discharge pipe 64 of the second-stage devolatilization extruder can be separately communicated with the circulating flow pipe 66 of the devolatilization extruder and the asphalt outlet 67 by controlling the fifth three-way solenoid valve 65. The devolatilization extruder circulating flow pipe 66 is communicated with the first-stage counter-rotating twin-screw devolatilization extruder 5 through a fourth three-way electromagnetic valve 56 and a first-stage devolatilization extruder feed pipe 54. A secondary devolatilization vacuum tube 68 is arranged at the middle section of the secondary devolatilization barrel 62, and a secondary vacuum pressure gauge 69 is arranged on the secondary devolatilization vacuum tube.

The vacuum filtration buffer tank 7 comprises a vacuum filtration buffer tank main body and a three-stage devolatilization vacuum port 71. The vacuum filtering buffer tank 7 is communicated with the primary devolatilization barrel 52 through a primary devolatilization vacuumizing tube 57; the vacuum filtration buffer tank 7 is communicated with the secondary devolatilization cylinder 62 through a secondary devolatilization vacuum pump 68. And finally, the three-stage devolatilization vacuumizing port 71 is connected to vacuum equipment, so that the first-stage counter-rotating twin-screw devolatilization extruder 5 and the second-stage counter-rotating twin-screw devolatilization extruder 6 are ensured to normally work in a vacuum state.

Wherein, the upper inlet of the magnetic force drive constant pressure stirrer 2 is communicated with the outlet of the counter-rotating double-screw conveying extruder 1, and the lower outlet of the magnetic force drive constant pressure stirrer 2 is communicated with the inlet of the static mixer 3. The outlet of the static mixer 3 is divided into two outlets by a second three-way electromagnetic valve 35, and one outlet is communicated with the conveying extruder circulating feeding pipe 17 of the counter-rotating twin-screw conveying extruder 1; the other outlet communicates with the separator feed pipe 41 of the static density separator 4. The outlet of the standing density separator 4 is divided into two outlets by a third three-way electromagnetic valve 44, and one outlet is communicated with the counter-rotating double-screw conveying extruder 1 through a light component conveying pipe 46 and a first three-way electromagnetic valve 18; the other outlet of the standing density separator 4 is communicated with the first-stage counter-rotating twin-screw devolatilization extruder 5 through a heavy component conveying pipe 45 and a fourth three-way electromagnetic valve 56. The outlet of the first-stage counter-rotating twin-screw devolatilization extruder 5 is communicated with the inlet of the second-stage counter-rotating twin-screw devolatilization extruder 6. The outlet of the second-stage counter-rotating twin-screw devolatilization extruder 6 is divided into two outlets by a fifth three-way electromagnetic valve 65, one outlet is an asphalt discharge port 67, and the other outlet is communicated with the inlet of the first-stage counter-rotating twin-screw devolatilization extruder 5 through a devolatilization extruder circulating flow pipe 66 and a fourth three-way electromagnetic valve 56. The vacuum filtration buffer tank 7 is communicated with the primary devolatilization barrel 52 of the primary counter-rotating twin-screw devolatilization extruder 5 through a primary devolatilization vacuum-pumping tube 57. The vacuum filtration buffer tank 7 is communicated with a secondary devolatilization barrel 62 of the secondary counter-rotating twin-screw devolatilization extruder 6 through a secondary devolatilization vacuum-pumping tube 68.

A closed loop among the counter-rotating double-screw conveying extruder 1, the magnetic drive constant-pressure stirrer 2 and the static mixer 3 is a raw material polymerization circulation path I; the second three-way electromagnetic valve 35 is connected with a fourth three-way electromagnetic valve 56 through a separator feeding pipe 41, a standing density separator 4, a volumetric metering delivery pump 43, a third three-way electromagnetic valve 44 and a light component delivery pipe 46 to form a raw material light and heavy component separation path II; a closed loop formed by the first-stage counter-rotating double-screw devolatilization extruder 5 and the second-stage counter-rotating double-screw devolatilization extruder 6 is a heavy component raw material distillation devolatilization path III; the first three-way solenoid valve 18 is connected to a third three-way solenoid valve 44 through a light component delivery pipe 46 to form a light component raw material repolymerization path iv.

The continuous cyclic polymerization distillation reaction system for preparing the mesophase pitch works under the high-temperature working condition, a heater or a heating medium cyclic heating system can be used for heating, and the working temperature is ensured through a temperature measuring element and a temperature controller. The whole system comprises a polymerization reaction part, a density separation part, a distillation devolatilization part and various pipeline valves, and the specific type is not limited.

It will be appreciated by those skilled in the art that the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The embodiments disclosed above are therefore to be considered in all respects as illustrative and not restrictive. All changes which come within the scope of or equivalence to the invention are intended to be embraced therein.