Solvent preparation system for high-quality aramid fiber
By designing a high-quality paraposition aramid solvent preparation system including calcium chloride aqueous solution storage tank, NMP aqueous solution storage tank, three-phase solvent preparation tank, dehydration tower and composite solvent storage tank, high-purity nitrogen protection and replacement technology are used to ensure that the entire preparation process is oxygen-free, solving the problem of difficult control of solvent preparation oxygen content in the existing technology, and achieving the preparation of high-quality composite solvents and the improvement of resin synthesis quality.
Patent Information
- Application Number
- CN202421862665.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-02
- Publication Date
- 2025-05-13
- Estimated Expiration
- 2034-08-02
AI Technical Summary
The solvent preparation process in the preparation of para-aramid resins has the problem of difficulty in controlling oxygen content, which affects the quality of the composite solvent and thus affects the synthesis quality of PPTA.
A high-quality para-aramid solvent preparation system was designed, including a calcium chloride aqueous solution storage tank, an NMP aqueous solution storage tank, a three-phase solvent preparation tank, a dehydration tower and a composite solvent storage tank. Through high-purity nitrogen protection and replacement technology, it ensures that the entire preparation process remains an oxygen-free environment and improves the quality of the composite solvent.
By strictly controlling the oxygen content of the mixed solution, the preparation of high-quality composite solvents is achieved, the quality problems in the resin synthesis process is solved, and economic benefits are improved.
Smart Images
Figure CN222855420U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of solvent preparation in the process of preparing para-aramid resin, and in particular to a solvent preparation system for high-quality aramid. Background Art
[0002] Para-aramid (PPTA), as one of the three high-performance fibers, is widely used in military, aviation, automotive and other fields due to its advantages such as high strength and high modulus. The synthesis of PPTA is mainly obtained by low-temperature solution polymerization in N-methylpyrrolidone (NMP) / calcium chloride composite solvent, with paraphenylenediamine and terephthaloyl chloride as monomers. The quality of the composite solvent directly affects the quality of PPTA. The composite solvent mainly consists of two parts, namely NMP and calcium chloride. As an organic substance, NMP is a colorless to light yellow transparent liquid with a slight ammonia smell, which can be infinitely miscible with water and many organic solvents. The preparation of the composite solvent is mainly to prepare a mixed solution of N-methylpyrrolidone and a co-solvent calcium chloride solution, which is transported to a dehydration device through a delivery pump, and dehydrated under high temperature and negative pressure conditions to prepare a composite solvent. Utility Model Content
[0003] In order to overcome the technical defects of the existing solvent preparation process conditions in the preparation of para-aramid resin, the utility model provides a solvent preparation system for high-quality para-aramid.
[0004] Based on the above purpose, the technical solution adopted by the utility model is:
[0005] A solvent preparation system for high-quality aramid fiber comprises a calcium chloride aqueous solution storage tank, an NMP aqueous solution storage tank, a three-phase solvent preparation tank, a dehydration tower and a composite solvent storage tank. The calcium chloride aqueous solution storage tank and the NMP aqueous solution storage tank are respectively connected to the calcium chloride aqueous solution inlet and the NMP aqueous solution inlet of the three-phase solvent preparation tank. The bottom outlet of the three-phase solvent preparation tank is connected to the middle of the dehydration tower through a pipeline. The bottom outlet of the dehydration tower is connected to the top inlet of the composite solvent storage tank through a pipeline. The calcium chloride aqueous solution storage tank, the NMP aqueous solution storage tank, the three-phase solvent preparation tank, the dehydration tower and the composite solvent storage tank are all connected to a high-purity nitrogen pipeline. The NMP aqueous solution storage tank, the three-phase solvent preparation tank and the composite solvent storage tank are also provided with a pressure gauge and an exhaust pipeline. The high-purity nitrogen pipeline and the exhaust pipeline of the NMP aqueous solution storage tank, the three-phase solvent preparation tank and the composite solvent storage tank are all provided with a solenoid valve, and the pressure gauge on each tank and the solenoid valve on the high-purity nitrogen pipeline and the exhaust pipeline of the tank are interlocked.
[0006] Furthermore, a delivery pump is provided on the pipeline between the calcium chloride aqueous solution storage tank and the three-phase solvent preparation tank, on the pipeline between the NMP aqueous solution storage tank and the three-phase solvent preparation tank, on the pipeline between the three-phase solvent preparation tank and the dehydration tower, and on the storage tank between the dehydration tower and the composite solvent storage tank.
[0007] Furthermore, two nitrogen nozzles are provided at the bottom of the calcium chloride aqueous solution storage tank so that high-purity nitrogen enters the calcium chloride aqueous solution storage tank from the bottom of the tank through the nozzles.
[0008] Furthermore, a vacuum unit is connected to the top of the dehydration tower so that the dehydration tower is in a negative pressure state.
[0009] Furthermore, a high-purity nitrogen supplementary pipeline is connected to the bottom of the dehydration tower, and a manual valve is provided on the high-purity nitrogen pipeline at the bottom of the dehydration tower.
[0010] The preparation process mainly prepares NMP aqueous solution and calcium chloride aqueous solution into a mixed solution, and finally prepares a high-quality composite solvent through refined dehydration. This system mainly transports the prepared calcium chloride aqueous solution to the storage tank through a pump, and the control of oxygen content in the entire composite solvent preparation process is a key factor affecting product quality. A certain amount of oxygen is dissolved in the calcium chloride aqueous solution in the storage tank. The oxygen in the solution has a greater impact on the quality of the composite solvent during the subsequent high-temperature dehydration process. Therefore, it is necessary to set a nitrogen pipeline and nozzle at the bottom of the calcium chloride aqueous solution storage tank. High-purity nitrogen enters the calcium chloride solution storage tank from the bottom of the tank through the nozzle, thereby efficiently replacing the dissolved oxygen in the solution. Before the calcium chloride aqueous solution and the NMP aqueous solution are prepared, the calcium chloride aqueous solution needs to be replaced with nitrogen for 2-3 hours before it can be carried out; and for the N in the NMP aqueous solution storage tank The MP aqueous solution is recycled and reused under high temperature and negative pressure conditions. At the same time, the NMP aqueous solution storage tank is protected by high-purity nitrogen. The tank pressure is interlocked with the nitrogen inlet pipeline valve and the exhaust pipeline valve to maintain the nitrogen sealing environment in the tank. When the calcium chloride aqueous solution and the NMP aqueous solution are mixed, nitrogen protection is also used to ensure that the entire mixed solution is in an oxygen-free condition before entering the dehydration device. In addition, the dehydration tower is replaced with nitrogen before starting to maintain an oxygen-free environment in the tower. After uniform mixing, the mixed solution with a high water content enters the dehydration tower. The top of the tower is connected to a vacuum unit to form a negative pressure evaporation environment during the dehydration and refining process to remove the water in the mixed solution, thereby preparing a high-quality composite solvent. The entire preparation and subsequent storage process need to maintain an oxygen-free environment. The deterioration of the composite solvent can directly affect the quality of PPTA synthesis.
[0011] The utility model has a simple structure and is easy to operate. By strictly controlling the oxygen content of the mixed solution in the solution during the entire dehydration process, the preparation of a high-quality composite solvent is achieved, thereby providing a reliable guarantee for the synthesis of high-quality para-aramid resin. The method achieves good economic benefits and solves quality problems such as resin color that exist in the current resin synthesis process. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 This is a process flow chart of the utility model;
[0013] In the figure: 1. Calcium chloride aqueous solution storage tank, 2 / 3. Nitrogen nozzle, 4. High-purity nitrogen pipeline of calcium chloride aqueous solution storage tank, 5. Calcium chloride aqueous solution delivery pump, 6. Exhaust pipeline of three-phase solvent preparation tank, 7. High-purity nitrogen pipeline of three-phase solvent preparation tank, 8. Solenoid valve of high-purity nitrogen pipeline of three-phase solvent preparation tank, 9. Solenoid valve of exhaust pipeline of three-phase solvent preparation tank, 10. Pressure gauge of three-phase solvent preparation tank, 11. Three-phase solution preparation tank, 12. Feed delivery pump of dehydration tower, 13. Dehydration tower, 14. Dehydration tower bottom delivery pump, 15. Composite solvent storage tank, 16. Pressure gauge of composite solution storage tank, 17. Solenoid valve of exhaust pipeline of composite solvent storage tank, 18. Solenoid valve of high-purity nitrogen pipeline of composite solvent storage tank, 19. Exhaust pipeline of composite solvent storage tank, 20. High-purity nitrogen pipeline of composite solvent storage tank, 21. Vacuum unit, 22. 1. NMP aqueous solution delivery pump, 23. NMP aqueous solution storage tank, 24. NMP aqueous solution storage tank pressure gauge, 25. NMP aqueous solution storage tank exhaust pipeline solenoid valve, 26. NMP aqueous solution storage tank high-purity nitrogen pipeline solenoid valve, 27. NMP aqueous solution storage tank high-purity nitrogen pipeline, 28. NMP aqueous solution storage tank exhaust pipeline, 29. Dehydration tower high-purity nitrogen pipeline, 30. Manual valve. DETAILED DESCRIPTION
[0014] In order to clearly illustrate the technical features of the present invention, the present invention is described in detail below through specific implementation methods and in conjunction with the accompanying drawings.
[0015] A solvent preparation system for high quality aramid fibers, such as Figure 1As shown, it includes a calcium chloride aqueous solution storage tank 1, an NMP aqueous solution storage tank 23, a three-phase solvent preparation tank 11, a dehydration tower 13 and a composite solvent storage tank 15, wherein the calcium chloride aqueous solution storage tank 1 is connected to the calcium chloride aqueous solution inlet of the three-phase solvent preparation tank 11 through a pipeline and a calcium chloride aqueous solution delivery pump 5 provided on the pipeline, and the NMP aqueous solution storage tank 23 is connected to the NMP aqueous solution inlet of the three-phase solvent preparation tank 11 through a pipeline and an NMP aqueous solution delivery pump 22 provided on the pipeline, and the bottom of the three-phase solvent preparation tank 11 is connected to the NMP aqueous solution inlet of the three-phase solvent preparation tank 11. The outlet of the dehydration tower 13 is connected to the middle inlet of the dehydration tower 13 through a pipeline and a dehydration tower feed delivery pump 12 arranged on the pipeline, the bottom outlet of the dehydration tower 13 is connected to the top inlet of the composite solvent storage tank 15 through a pipeline and a dehydration tower bottom delivery pump 14 arranged on the pipeline, the bottom of the calcium chloride aqueous solution storage tank 1 is connected to a calcium chloride aqueous solution storage tank high-purity nitrogen pipeline 4, and two nitrogen nozzles 2 and 3 are arranged in the calcium chloride aqueous solution storage tank 1, and the two nitrogen nozzles (2 and 3) are both connected to the calcium chloride aqueous solution storage tank high-purity nitrogen pipeline 4;
[0016] An NMP aqueous solution storage tank pressure gauge 24, an NMP aqueous solution storage tank high-purity nitrogen pipeline 27 and an NMP aqueous solution storage tank exhaust pipeline 28 are provided on the top of the NMP aqueous solution storage tank 23. An NMP aqueous solution storage tank high-purity nitrogen pipeline solenoid valve 26 is provided on the NMP aqueous solution storage tank high-purity nitrogen pipeline pipeline 27, and an NMP aqueous solution storage tank exhaust pipeline solenoid valve 25 is provided on the NMP aqueous solution storage tank exhaust pipeline 28. The NMP aqueous solution storage tank pressure gauge 24, the NMP aqueous solution storage tank exhaust pipeline solenoid valve 25 and the NMP aqueous solution storage tank high-purity nitrogen pipeline solenoid valve 26 are interlocked.
[0017] The top of the three-phase solvent preparation tank 11 is provided with a three-phase solvent preparation tank pressure gauge 10, a three-phase solvent preparation tank exhaust pipeline 6 and a three-phase solvent preparation tank high-purity nitrogen pipeline 7. The three-phase solvent preparation tank exhaust pipeline 6 is provided with a three-phase solvent preparation tank exhaust pipeline solenoid valve 9. The three-phase solvent preparation tank high-purity nitrogen pipeline 7 is provided with a three-phase solvent preparation tank high-purity nitrogen pipeline solenoid valve 8. The three-phase solvent preparation tank pressure gauge 10, the three-phase solvent preparation tank high-purity nitrogen pipeline solenoid valve 8 and the three-phase solvent preparation tank exhaust pipeline solenoid valve 9 are interlocked.
[0018] A composite solution storage tank pressure gauge 16, a composite solvent storage tank exhaust pipeline 19 and a composite solvent storage tank high-purity nitrogen pipeline 20 are provided on the top of the composite solvent storage tank 15; a composite solvent storage tank exhaust pipeline solenoid valve 17 is provided on the composite solvent storage tank exhaust pipeline 19; a composite solvent storage tank high-purity nitrogen pipeline solenoid valve 18 is provided on the composite solvent storage tank high-purity nitrogen pipeline 20; the composite solution storage tank pressure gauge 16, the composite solvent storage tank exhaust pipeline solenoid valve 17 and the composite solvent storage tank high-purity nitrogen pipeline solenoid valve 18 are interlocked.
[0019] The top of the dehydration tower 13 is connected to a vacuum unit 21 so that the dehydration tower 13 is in a negative pressure state.
[0020] A dehydration tower high-purity nitrogen pipeline 29 is provided at the bottom of the dehydration tower 13 , and a manual valve 30 is provided on the dehydration tower high-purity nitrogen pipeline 29 .
[0021] In practice, if Figure 1 As shown in the figure, the process mainly involves transferring the NMP aqueous solution with a water content of about 10-15wt% recovered under high temperature and negative pressure conditions in the previous process in the NMP aqueous solution storage tank 23 to the three-phase solution preparation tank 11 through the NMP aqueous solution delivery pump 22. At the same time, the calcium chloride aqueous solution with a concentration of about 30-35wt% prepared in the calcium chloride aqueous solution storage tank 1 and the calcium chloride solution after high-purity nitrogen replacement for 2-3 hours are delivered to the three-phase solution preparation tank 11 through the calcium chloride solution delivery pump 5 to mix with the NMP aqueous solution. The uniformly mixed three-phase solution is delivered to the dehydration tower 13 for dehydration through the dehydration tower feed delivery pump 12. The dehydration tower 13 is connected to a vacuum negative pressure unit 21 to keep the dehydration tower 13 at about -70 kPa. After negative pressure dehydration, a high-quality composite solvent with a water content of ≤300ppm is obtained. In order to ensure that the whole process is carried out under oxygen-free conditions, the NMP aqueous solution storage tank 23 and the three-phase solution preparation tank 11 are both provided with nitrogen protection, and the tank body is fed with high-purity nitrogen, and the electromagnetic valve is interlocked with the tank body pressure gauge to control a certain pressure, and the nitrogen is automatically supplemented when the pressure is low, and the exhaust line electromagnetic valve is opened to exhaust when the pressure is high, and the storage tank is kept in a nitrogen environment to prevent oxygen from entering the system. In addition, the dehydration tower 13 needs to open the manual valve 29 before driving to pass nitrogen replacement to maintain the oxygen-free environment in the tower, and the mixed solution with a higher water content after mixing evenly enters the dehydration tower 13, and the tower top is connected to the vacuum unit 21 to form a negative pressure evaporation environment in the dehydration and refining process to remove the water in the mixed solution, thereby preparing a high-quality composite solvent.
[0022] The above-mentioned specific implementation manner cannot be used as a limitation on the protection scope of the present utility model. For those skilled in the art, any replacement, improvement or change made to the implementation manner of the present utility model falls within the protection scope of the present utility model.
[0023] The matters not described in detail in the present invention are all known technologies to those skilled in the art.
Claims
1. A solvent preparation system for high-quality aramid fiber, comprising a calcium chloride aqueous solution storage tank, an NMP aqueous solution storage tank, a three-phase solvent preparation tank, a dehydration tower and a composite solvent storage tank, characterized in that: The calcium chloride aqueous solution storage tank and the NMP aqueous solution storage tank are respectively connected to the calcium chloride aqueous solution inlet and the NMP aqueous solution inlet of the three-phase solvent preparation tank, the bottom outlet of the three-phase solvent preparation tank is connected to the middle of the dehydration tower through a pipeline, the bottom outlet of the dehydration tower is connected to the top inlet of the composite solvent storage tank through a pipeline, the calcium chloride aqueous solution storage tank, the NMP aqueous solution storage tank, the three-phase solvent preparation tank, the dehydration tower and the composite solvent storage tank are all connected to a high-purity nitrogen pipeline, the NMP aqueous solution storage tank, the three-phase solvent preparation tank and the composite solvent storage tank are also provided with a pressure gauge and an exhaust pipeline, the high-purity nitrogen pipeline and the exhaust pipeline of the NMP aqueous solution storage tank, the three-phase solvent preparation tank and the composite solvent storage tank are all provided with a solenoid valve, and the pressure gauge on each tank and the solenoid valve on the high-purity nitrogen replenishment pipeline and the exhaust pipeline of the tank are interlocked.
2. The solvent preparation system for high-quality aramid fiber according to claim 1, characterized in that: Delivery pumps are provided on the pipeline between the calcium chloride aqueous solution storage tank and the three-phase solvent preparation tank, on the pipeline between the NMP aqueous solution storage tank and the three-phase solvent preparation tank, on the pipeline between the three-phase solvent preparation tank and the dehydration tower, and on the storage tank between the dehydration tower and the composite solvent storage tank.
3. The solvent preparation system for high-quality aramid fiber according to claim 1, characterized in that: Two nitrogen nozzles are arranged at the bottom of the calcium chloride aqueous solution storage tank so that high-purity nitrogen enters the calcium chloride aqueous solution storage tank from the bottom of the tank through the nozzles.
4. The solvent preparation system for high-quality aramid fiber according to claim 1, characterized in that: The top of the dehydration tower is connected to a vacuum unit so that the dehydration tower is in a negative pressure state.
5. The solvent preparation system for high-quality aramid fiber according to claim 1, characterized in that: The high-purity nitrogen pipeline is connected to the bottom of the dehydration tower, and a manual valve is arranged on the high-purity nitrogen pipeline at the bottom of the dehydration tower.