Aramid polymer filtering, washing and drying system and application

Abstract

The invention provides an aramid fiber polymer filtering, washing and drying system and application. The system comprises a rotary pressure filter, a conveying unit, a gas carrying unit and a spiral-flow type drying device which are connected in sequence, the rotary pressure filter is used for filtering, washing and dehumidifying the mixture containing the aramid polymer to obtain a filter cake; the conveying unit is used for further scattering the filter cake and conveying the filter cake to the spiral-flow type drying device; the carrier gas unit is used for introducing gas into the spiral-flow type drying device and blowing the polymer so as to increase the particle rotation speed and take away moisture in the aramid polymer from the spiral-flow type drying device; the spiral-flow type drying device is used for drying particles through high-speed rotation. Through the combination of the rotary pressure filter and the spiral-flow type drying device, the energy consumption in the aramid fiber polymer drying process can be reduced.

Description

Technical Field

[0001] This application relates to the technical field of aramid polymers, and specifically relates to an aramid polymer filtration, washing, and drying system and its application. Background Art

[0002] In the production process of aramid, a liquid-solid mixture of para-aramid, N-methylpyrrolidone, calcium chloride, and sodium chloride is obtained after the polymerization of p-phenylenediamine and terephthaloyl chloride. The aramid polymer is suspended in the mixed solvent in the form of powder particles, and the liquid-solid mixture needs to be separated sequentially. The existing polymer separation is completed through the combination of a belt filter and one or more rotary drum tube-sheet dryers. Since the belt filter generally filters under negative pressure, the solvent is replaced through multiple water washes, and the moisture content of the filter cake after filtration is as high as 70-80%. Then, it is dried through a rotary drum tube-sheet dryer, and 70-80% of the moisture is taken away by heating and converted into water vapor.

[0003] Another method for filtering, washing, and drying para-aramid polymer is through the combination of a belt filter, a centrifuge, and a dryer. This method adds a centrifuge on the original basis, which can appropriately reduce the moisture content of the filter cake entering the dryer. However, because the centrifuge itself also has a relatively large energy consumption and it is difficult to reduce the moisture content of the filter cake to a satisfactory level. Summary of the Invention

[0004] In order to reduce the energy consumption during the drying process of aramid polymer, this application proposes an aramid polymer filtration, washing, and drying system and its application, and adopts the following technical solutions:

[0005] In the first aspect, this application discloses an aramid polymer filtration, washing, and drying system, which includes a rotary pressure filter, a conveying unit, a carrier gas unit, and a cyclone dryer connected in sequence;

[0006] The rotary pressure filter is used to filter, wash, and dehumidify the mixture containing aramid polymer to obtain an aramid polymer filter cake;

[0007] The conveying unit is used to break up the aramid polymer filter cake and transport it to the cyclone dryer;

[0008] The carrier gas unit is used to introduce carrier gas into the cyclone dryer, blow the aramid polymer filter cake, and take away the moisture in the aramid polymer filter cake from the cyclone dryer;

[0009] The cyclone dryer is used to dry the aramid polymer filter cake by high-speed rotation.

[0010] By adopting the above technical solution, the rotary pressure filter completes the processes of filtering, washing, and dehumidifying the aramid polymer mixture in one device, greatly reducing the floor area of the device and simplifying the material transfer process; the low-temperature non-phase-change dehydration device, the cyclone dryer, realizes the low-temperature dehydration of particles through the coupling oscillation of high-speed self-rotation and revolution, achieving the low-temperature, rapid, and low-energy consumption drying of capillary liquid, surface liquid, and pore liquid, avoiding the loss of latent heat of vaporization and reducing the energy consumption of the entire system; at the same time, the conveying unit crushes the filter cake into particles during the transportation of the filter cake, increasing the subsequent dehydration surface area of the particles and further improving the drying efficiency.

[0011] Optionally, the rotary pressure filter includes a dehumidification zone, and the dehumidification zone has a dry gas inlet for introducing dry gas into the dehumidification zone for dehumidification.

[0012] Optionally, the rotary pressure filter further includes a filtration zone, a washing zone, and a discharging zone; the filtration zone, the washing zone, the dehumidification zone, and the discharging zone are circumferentially distributed along the rotary pressure filter.

[0013] By adopting the above technical solution, the processes of filtering, washing, and dehumidifying the aramid polymer are sequentially completed by the rotary pressure filter, and the sequence and quantity of each functional zone can be adjusted according to actual requirements, improving the overall drying efficiency.

[0014] Optionally, the pressure range of the filtration zone is 0.4 - 0.6 MPaG, the pressure range of the washing zone is 0.3 - 0.7 MPaG, and the pressure range of the dehumidification zone is 0.2 - 0.5 MPaG.

[0015] Optionally, the temperature range of the filtration zone is 100 - 180 °C, the temperature range of the washing zone is 60 - 175 °C, and the temperature range of the dehumidification zone is 50 - 120 °C.

[0016] Optionally, the washing zone includes a primary washing zone and a secondary washing zone;

[0017] The primary washing zone is used for water washing the mixture;

[0018] The secondary washing zone is used for steam washing the mixture.

[0019] By adopting the above technical solution, the aramid polymer is washed in the form of a combination of water washing and steam washing. The steam can penetrate into the tiny pores and fine gaps on the surface of the object, and the water in the fine pores can still continue to be removed.

[0020] Optionally, the pressure range of the primary washing zone is 0.3 - 0.4 MPaG, and the temperature range is 80 - 100 °C;

[0021] The pressure range of the secondary washing area is 0.35 - 0.7 MPaG, and the temperature range is 100 - 175 °C.

[0022] Optionally, the filtration area has a steam inlet for introducing steam to filter the mixture.

[0023] By adopting the above technical solution, since the thick capillary pores in the filter cake often dehydrate first and then air enters, it is extremely easy to form a short circuit, making it difficult to remove the water in the fine pores. Therefore, steam pressurization filtration is adopted in the filtration area. By adding saturated steam, while the water in the thick pores is dehydrated, the steam condensate can block the thick pores, preventing air short circuit, and the water in the fine pores can still continue to be removed.

[0024] Optionally, the high-pressure steam pressure is 0.35 - 0.7 MPaG, and the temperature is 100 - 175 °C.

[0025] In a second aspect, the present application provides an application of the aramid polymer filtration, washing, and drying system as described in the first aspect in the production of para-aramid polymer.

[0026] Based on the above technical solution, the beneficial effects of the present application compared with the prior art are as follows:

[0027] In the present application, the filtration, washing, and dehumidification processes of the para-aramid polymer mixture are concentrated in one device by a rotary pressure filter, greatly reducing the floor area of the device and simplifying the material transfer process; a low-temperature non-phase change dehydration device, a cyclone dryer, is used to achieve low-temperature dehydration of particles through the coupling oscillation of high-speed self-rotation and revolution, realizing low-temperature, fast, and low-consumption drying of capillary liquid, surface liquid, and pore liquid, avoiding the loss of latent heat of vaporization and reducing the energy consumption of the entire system; at the same time, the conveying unit crushes the filter cake into particles during the transportation of the filter cake, increasing the subsequent dehydration surface area of the particles, thereby improving the drying efficiency. By combining the rotary pressure filter and the cyclone dryer, the moisture content of the para-aramid polymer particles in the present application can be reduced to less than 0.5%. Description of the Drawings

[0028] Figure 1 is the overall schematic diagram of the drying system in the embodiment of the present application;

[0029] Figure 2 is the schematic diagram of the rotary pressure filter in the embodiment of the present application;

[0030] Description of the Reference Numerals:

[0031] 1. Rotary pressure filter; 11. Filtration area; 12. Primary washing area; 13. Secondary washing area; 14. Dehumidification area; 15. Discharge area; 2. Conveying unit; 3. Carrier gas unit; 4. Cyclone dryer. Detailed Embodiments

[0032] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be fully conveyed to those skilled in the art.

[0033] Exemplary embodiments will be described in detail herein, and examples thereof are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0034] In the description of the present disclosure, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. These are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present disclosure. In addition, the terms "first", "second", "third" are only used for descriptive purposes and should not be construed as indicating or implying relative importance.

[0035] In the description of the present disclosure, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present disclosure can be understood according to specific circumstances.

[0036] When the inventor washed, filtered, dehumidified, and dried aramid polymers with reference to the prior art, it was found that: during the entire drying process of aramid polymers, a variety of devices are often required, which not only occupy a large area but also consume a large amount of energy to dry the para-aramid polymer to a required degree. Currently, aramid polymers usually adopt the principle of heat drying. When heat drying, the water in the para-aramid polymer will undergo a phase change, changing from a liquid state to a gaseous state. During the phase change process, due to the latent heat of vaporization, huge energy consumption is generated.

[0037] In order to reduce the overall energy consumption during the drying process of para-aramid polymer, the inventor has conducted further research and made this invention.

[0038] In a first aspect, the present application discloses an aramid polymer filtration, washing, and drying system. Referring to Figure 1 , the polymer filtration, washing, and drying system includes a rotary pressure filter 1, a conveying unit 2, a carrier gas unit 3, and a cyclone dryer 4. The rotary pressure filter 1 is used to filter, wash, and dehumidify the mixture containing aramid polymer to obtain a filter cake; the conveying unit 2 is used to break up the filter cake and transport it to the cyclone dryer 4; the carrier gas unit 3 is used to introduce carrier gas into the cyclone dryer 4 to blow the aramid polymer filter cake and take away the moisture in the aramid polymer filter cake from the cyclone dryer 4; the cyclone dryer 4 is used to dry the aramid polymer filter cake by high-speed rotation.

[0039] In the aramid polymer filtration, washing, and drying system of the present application, the processes of filtering, washing, and dehumidifying the mixture containing aramid polymer are concentrated in one device, namely the rotary pressure filter 1, which greatly reduces the floor area of the device and simplifies the material transfer process. While transporting the filter cake, the conveying unit 2 further breaks up the dehumidified filter cake to reduce the particle size of the material entering the cyclone dryer, increase the drying surface area of the material, and improve the subsequent drying efficiency. The cyclone dryer realizes the low-temperature dehydration of particles through the coupling oscillation of high-speed self-rotation and revolution, without phase change. By using the self-revolution coupling-induced microchannel oscillation centrifugal force to overcome the micro-interface capillary force, it realizes the low-temperature, fast, and low-energy consumption drying of capillary liquid, surface liquid, and pore liquid, avoids the loss of latent heat of vaporization, does not require converting water into water vapor, and reduces the energy consumption of the entire system.

[0040] In an optional embodiment, referring to Figure 2 , the rotary pressure filter 1 includes a circumferentially distributed filtration area 11, a washing area, a dehumidification area 14, and a discharging area 15. In other embodiments, according to different working conditions, it may also include a pre-drying area. It should be noted that the number and sequence of each functional area of the rotary pressure filter 1 can be adjusted according to actual needs. For example, it can be 1-2 filtration areas 11, 1-3 washing areas, 1-3 dehumidification areas 14, 1 discharging area 15, and 1-3 pre-drying areas, and can be arranged in the order of pre-drying area, filtration area 11, washing area, dehumidification area 14, filtration area 11, washing area, dehumidification area 14, discharging area 15, or can also be arranged in the order of pre-drying area, filtration area 11, filtration area 11, washing area, washing area, dehumidification area 14, dehumidification area 14, discharging area 15.

[0041] In an optional embodiment, the rotary pressure filter 1 includes four functional zones, namely a filtration zone 11, a washing zone, a dehumidification zone 14, and a discharging zone 15. Among them, the pressure range of the filtration zone 11 is 0.4 - 0.6 MPaG, the pressure range of the washing zone is 0.3 - 0.7 MPaG, and the pressure range of the dehumidification zone 14 is 0.2 - 0.5 MPaG. The temperature range of the filtration zone 11 is 100 - 180 °C, the temperature range of the washing zone is 60 - 175 °C, and the temperature range of the dehumidification zone 14 is 50 - 120 °C. The para-aramid polymer wet material first enters the filtration zone 11 and flows out from the discharging zone 15 after filtration, washing, and dehumidification.

[0042] Specifically, the filtration zone 11 has a steam inlet for introducing steam to pressurize and filter the mixture. The steam can be water vapor, with a steam pressure of 0.35 - 0.7 MPaG and a temperature of 100 - 175 °C, preferably 0.45 MPaG and 150 °C. At the same time, the pressure difference across the filter cake is maintained at 0.15 - 0.2 MPaG. Since the thick capillary pores in the filter cake often dehydrate first and then air enters, it is extremely easy to form a short circuit, making it difficult to remove the water in the fine pores. Therefore, steam pressurization filtration is adopted. While the thick pores are dehydrating, the steam condensate can block the thick pores, preventing air short circuits, and the water in the fine pores can still continue to be removed.

[0043] Furthermore, the washing zone includes a primary washing zone 12 and a secondary washing zone 13 arranged in sequence. The filtration zone 11, the primary washing zone 12, the secondary washing zone 13, the dehumidification zone 14, and the discharging zone 15 are sequentially and evenly spaced along the circumferential direction. The primary washing zone 12 is used for water washing the mixture; the secondary washing zone 13 is used for steam washing the water-washed mixture, and the steam can be water vapor. The aramid polymer is washed in a combination of water washing and steam washing. The steam can penetrate into the tiny pores and fine gaps on the surface of the object, and the water in the fine pores can still continue to be removed.

[0044] Specifically, the pressure range of the primary washing zone 12 is 0.3 - 0.5 MPaG, preferably 0.3 MPaG, and the temperature range is 80 - 90 °C, preferably 85 °C; the pressure range of the secondary washing zone 13 is 0.35 - 0.7 MPaG, preferably 0.45 MPaG, and the temperature range is 100 - 175 °C, preferably 150 °C.

[0045] Furthermore, the dehumidification zone 14 has a dry gas inlet for introducing dry gas into the dehumidification zone 14 to perform pneumatic dehumidification. Specifically, the dry gas can be air, nitrogen, or an inert gas. The carrier gas pressure is 0.25 - 0.5 MPaG, preferably 0.3 MPaG, and the temperature is 50 - 120 °C, preferably 90 °C.

[0046] Furthermore, the unloading area 15 is also provided with a back-flushing gas inlet for introducing back-flushing gas, and the back-flushing gas causes the filter cake to fall off by reverse blowing.

[0047] In an optional embodiment, the metal material in contact with the medium in the rotary pressure filter 1 of the present invention is selected from austenitic stainless steel, duplex steel, Hastelloy or titanium, etc.; the non-metallic material is selected from PTFE, PEEK, etc.

[0048] In an optional embodiment, the conveying unit 2 in this embodiment may be a screw conveyor, which breaks up the aramid polymer filter cake during the process of transporting the filter cake so as to facilitate the subsequent rotary drying process.

[0049] Furthermore, the cyclone dryer 4 in the present application is a low-temperature non-phase-change dehydration device, and the operating temperature is 50-90°C, preferably 50°C. The carrier gas unit 3 can be a gas compressor, and the carrier gas unit 3 can increase the rotation speed of the aramid polymer while blowing the aramid polymer to the cyclone dryer 4, and the rotation speed of the aramid polymer reaches 20000-50000r / min. Specifically, the carrier gas used in the carrier gas system 3 can be nitrogen, air or an inert gas, and the water in the aramid polymer is removed by the dispersed filter cake under the action of rotation and revolution in the cyclone dryer, and the aramid polymer falls from the wall of the device, and the carrier gas leaves the cyclone dryer 4 from the carrier gas outlet with the water.

[0050] In a specific embodiment, the rotary pressure filter 1 in the present application can reduce the moisture content of the aramid polymer to less than 10% through the combination of the filtering area 11, the washing area, the dehumidification area 14, and the unloading area 15, and can further reduce the moisture content of the aramid polymer to less than 0.5% through the cyclone dryer 4. The entire filtering, washing, and drying system is adapted to the characteristics of the aramid polymer itself, and the energy consumption is reduced by more than 30% under the premise of meeting the dehumidification rate of the aramid polymer, and has the advantages of low cost, small footprint, and high drying efficiency.

[0051] In a second aspect, the present application discloses an application of the above-mentioned aramid polymer filtering, washing and drying system in the production of para-aramid polymer.

[0052] Specifically, when the aramid polymer is dried using the drying system in the present application, the neutralized aramid polymer (polymer particle size is 80μm-2500μm) is transported to the rotary pressure filter 1 for filtration, washing, dehumidification, and unloading to obtain a filter cake; the filter cake is further broken up by the action of the spiral conveying unit 2, and is blown to the cyclone dryer 4 for final drying by the action of the carrier gas unit 3.

[0053] The present application is described in detail below through specific examples and comparative examples:

[0054] Example 1

[0055] In the mixture containing aramid polymer, the solid content of the aramid polymer is 23%, the moisture content is 77%, and the mixture temperature is 25°C. The aramid polymer mixture is fed into a rotary pressure filter. The pressure in the filtration zone 11 of the rotary pressure filter is 0.4 MPaG, and pneumatic filtration is carried out using steam in the filtration zone 11. The steam pressure is 0.45 MPaG, 150°C, and the pressure difference across the filter cake is maintained at about 0.15 MPaG. The filtered mixture enters the primary washing zone 12 and is subjected to primary washing with washing water at a pressure of 0.3 MPaG and a temperature of 80°C, and then enters the secondary washing zone 13 and is subjected to secondary washing with steam at a pressure of 0.45 MPaG and a temperature of 150°C. The washed mixture enters the dehumidification zone 14, and pneumatic dehumidification is carried out by introducing dry nitrogen into the dehumidification zone 14. The pressure of the dry nitrogen is 0.25 MPaG, and the temperature is 90°C. Finally, the filter cake drops from the discharge zone 15 to the screw conveyor, and the moisture content of the aramid polymer coming out of the rotary pressure filter is 8.5%.

[0056] The filter cake is transported by a screw conveyor into a cyclone dryer. The carrier gas unit uses nitrogen, the inlet flow rate of nitrogen is 10 m / s, the operating temperature in the cyclone dryer is 50°C, and the rotation speed of the particles in the cyclone dryer reaches 25000 r / min. The moisture content of the gas at the carrier gas outlet of the cyclone dryer is 30%, and the moisture content of the aramid polymer particles at the material outlet of the cyclone dryer is 0.3%.

[0057] Comparative Example 1

[0058] In this comparative example, a belt filter, a polymer steam tube dryer, and a rinsing tower are used comprehensively to filter and dry the mixture containing aramid polymer.

[0059] Specifically, the aramid polymer mixture from the previous process is pumped into a multi-stage belt filter (10 stages in this example) for filtration. The solid content is 23%, the moisture content is 77%, and the mixture temperature is 25°C. When flushing the first stage or the first two stages of the belt filter, NaOH with a concentration of 23% is added to adjust the pH value of the final product. The filtration mother liquor enters the recycled mother liquor storage tank and is pumped to the solvent recovery device for treatment; then the filtrates of each stage flow countercurrently back to the belt filter to rinse the polymer filter cake for reuse; after the last stage of filtration is completed, the filter cake is fed into the polymer steam tube dryer by a screw feeder through a hopper, and the filter cloth is rinsed with the rinsing liquid from the rinsing tower of the dryer. The rinsing liquid is collected and pumped to the previous stage of the belt filter for reuse. The moisture content of the aramid polymer in the filter cake of the belt filter is 33%.

[0060] The polymer dryer is a steam tube rotary drum dryer. The carrier gas unit uses hot nitrogen. The inlet temperature of nitrogen is 60 °C and the flow rate is 0.7 m / min. The working temperature inside the dryer is 160 °C. The residual solvent and water in the filter cake are evaporated and discharged from the feed end along with the backflush nitrogen into the scrubbing tower, where they are scrubbed with demineralized water. The uncondensed gas is transported by a fan to the nitrogen preheater for heating and then recycled, while the lost nitrogen is replenished. The moisture content of the carrier gas at the gas outlet of the dryer is 16%, and the moisture content of the aramid polymer particles at the outlet is 1%. After the dried polymer is discharged through a rotary valve, it is pneumatically conveyed to the dry polymer silo for storage.

[0061] According to the above specific embodiments and comparative examples, the combination of the rotary pressure filter 1 and the cyclone dryer 4 in the present application can reduce the moisture content of the para-aramid polymer to less than 0.5%, which is higher than that of the aramid polymer particles obtained by using a conventional filtration and drying system in the prior art.

[0062] The above description includes examples of one or more embodiments. Of course, it is impossible to describe all possible combinations of components or methods for the purpose of describing the above embodiments, but those of ordinary skill in the art should recognize that the various embodiments can be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications, and variations that fall within the scope of the appended claims. In addition, with respect to the term "comprising" used in the specification or claims, this term is covered in a manner similar to the term "including", as "including" is interpreted as a transitional term in the claims. In addition, any use of the term "or" in the specification or claims of the claims is intended to mean "non-exclusive or".

Claims

1. An aramid polymer filtration, washing, and drying system, characterized in that, It includes a rotary pressure filter, a conveying unit, a carrier gas unit and a cyclone dryer connected in sequence; The rotary pressure filter is used to filter, wash and dehumidify the mixture containing aramid polymer to obtain an aramid polymer filter cake; The conveying unit is used to break up the aramid polymer filter cake and transport it to the cyclone dryer; The carrier gas unit is used to introduce carrier gas into the cyclone dryer, blow the aramid polymer filter cake, and take away the moisture in the aramid polymer filter cake from the cyclone dryer; The cyclone dryer is used to dry the aramid polymer filter cake by high-speed rotation.

2. The aramid polymer filtration, washing, and drying system according to claim 1, characterized in that The rotary pressure filter includes a dehumidification zone; The dehumidification zone has a gas inlet for introducing dry gas into the dehumidification zone for dehumidification.

3. The aramid polymer filtration, washing, and drying system according to claim 2, characterized in that, The rotary pressure filter further includes a filtration zone, a washing zone and a discharging zone; The filtration zone, the washing zone, the dehumidification zone and the discharging zone are circumferentially distributed along the rotary pressure filter.

4. The aramid polymer filtration, washing and drying system according to claim 3, wherein, The pressure range of the filtration zone is 0.4 - 0.6 MPaG, the pressure range of the washing zone is 0.3 - 0.7 MPaG, and the pressure range of the dehumidification zone is 0.2 - 0.5 MPaG.

5. The aramid polymer filtration, washing, and drying system according to claim 2, wherein, The temperature range of the filtration zone is 100 - 180 °C, the temperature range of the washing zone is 60 - 175 °C, and the temperature range of the dehumidification zone is 50 - 120 °C.

6. The aramid polymer filtration, washing and drying system according to claim 3, wherein The washing zone includes a primary washing zone and a secondary washing zone; The primary washing zone is used to wash the mixture with water; The secondary washing zone is used to wash the mixture with steam.

7. The aramid polymer filtration, washing, and drying system according to claim 6, wherein, The pressure range of the primary washing zone is 0.3 - 0.4 MPaG, and the temperature range is 60 - 100 °C; The pressure range of the secondary washing zone is 0.35 - 0.7 MPaG, and the temperature range is 100 - 175 °C.

8. The aramid polymer filtration, washing, and drying system according to claim 2, wherein, The filtration zone has a steam inlet for introducing steam for pressurization to filter the mixture.

9. The aramid polymer filtration, washing and drying system according to claim 8, characterized in that, The steam pressure is 0.35 - 0.7 MPaG, and the temperature is 100 - 175 °C.

10. Application of the aramid polymer filtration, washing and drying system according to any one of claims 1 - 9 in the production of aramid polymer.

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