A precipitation fiber purification device, its purification process, a precipitation fiber precipitation and purification device

Abstract

A precipitation fiber purification device, its purification process, a precipitation fiber precipitation and purification device. The purification device includes a precipitation fiber slurry feeding port (12), a purification chamber (17), a conveying device, and a discharge port (22). The precipitation fiber slurry feeding port (12) is arranged at the head of the purification chamber (17), and the discharge port (22) is arranged at the tail of the purification chamber (17). The conveying device is installed inside the purification chamber (17). The conveying device inside the purification chamber (17) conveys the unprecipitated precipitation fiber from the precipitation fiber slurry feeding port (12) to the discharge port (22), and continuously sprays and washes the precipitation fiber during the conveying process. There are washing water spray holes (21) for spraying and washing and a spray washing water recycling system inside the purification chamber (17). The whole is wet purification, which can keep the precipitation fiber at a relatively high humidity during the purification process, enable the washing water to uniformly penetrate into the material, improve the purification efficiency, and make the washing more uniform and thorough.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and particularly relates to a precipitation fiber purification device and its purification process, as well as a precipitation fiber precipitation and purification device. Background Art

[0002] During the production process of precipitation fibers, chlorine-containing by-products are generated in the polymerization stage, and polar solvents (mainly DMAc) are used in the forming process. These impurities must be purified. Otherwise, if they are introduced into aramid paper, it will greatly affect the electrical insulation performance and anti-aging performance of aramid paper.

[0003] Currently, there are two purification methods adopted in China. One is centrifuge intermittent pulp washing, such as the technical solution disclosed in Chinese Patent CN201610656707.7. The centrifuge intermittent pulp washing has low efficiency and is suitable for laboratory research work. The other is horizontal belt continuous pulp washing. Industrial production generally adopts horizontal belt continuous pulp washing. This equipment is generally used for washing inorganic substances such as minerals and rare earths. It has only been achieved in recent years through continuous optimization and transformation of the equipment for washing precipitation fibers. For example, Chinese Patent CN201610885181.X realizes countercurrent washing on the washing bed. Whether it is centrifuge intermittent pulp washing or horizontal belt continuous pulp washing, in both methods, the raw materials are first dehydrated to a relatively dry state and then washed during the purification process. The advantage of this is that it can greatly reduce the waste liquid generated during the purification process and lower the production cost. However, the disadvantage is that the final product is a filter cake with a relatively high dryness, and it needs to be further pulped and defibered during the papermaking stock preparation process. During the secondary pulping and defibering process, it will cause changes in the morphology of precipitation fibers and damage to the film structure, increasing the content of fines. At the same time, when performing belt washing or centrifuge washing at a relatively high dryness, since the precipitation fiber pulp block is in a static state and the pulp block and the washing water always maintain the same contact surface, it may lead to uneven and incomplete washing. Summary of the Invention

[0004] The technical problem to be solved by the present invention is that belt washing or centrifuge washing at a high dryness leads to uneven and incomplete washing. To overcome the above-mentioned deficiencies and defects in the background art, the present invention provides a precipitation fiber purification device and its purification process, as well as a precipitation fiber precipitation and purification device.

[0005] To solve the above technical problem, the technical solution proposed by the present invention is as follows:

[0006] A precipitation fiber purification device includes a precipitation fiber slurry inlet, a purification chamber, a conveying device, and a discharge outlet. The precipitation fiber slurry inlet is arranged at the head of the purification chamber, the discharge outlet is arranged at the tail of the purification chamber, and the conveying device is installed in the purification chamber. The conveying device in the purification chamber conveys the unprecipitated precipitation fiber from the precipitation fiber slurry inlet to the discharge outlet, and continuously sprays and washes the precipitation fiber during the conveying process. There are washing water spray holes for spraying and washing and a spray washing water recycling system in the purification chamber.

[0007] In the present invention, a screw is arranged in the purification device, and at the same time, a sieve plate and a vacuum suction box are used for filtration and purification. On the basis of conventional horizontal belt pulp washing, the precipitation fiber can also be flipped, making the material dispersion more uniform, and the fiber is washed in a liquid form, avoiding the problem of needing to break and disperse the pulp due to high dryness.

[0008] Preferably, the spray washing water recycling system includes a sieve plate arranged at the lower end of the purification chamber and a vacuum suction box connected to the lower end of the sieve plate. The water outlet at the lower end of the vacuum suction box is connected to a gas-liquid separator through a washing water pipe, and the filtrate outlet of the gas-liquid separator is communicated with the washing water spray holes.

[0009] Preferably, the washing water pipes are connected in a multi-stage countercurrent manner. The filtrate received by the first-stage washing water pipe is transported to the solvent recovery system, the filtrate received by the subsequent multi-stage washing water pipes is transported to the washing water spray holes of the previous stage, and the washing water spray holes of the last stage are externally connected to pure water.

[0010] Adopting the multi-stage countercurrent manner can reduce the amount of waste liquid generated and increase the waste liquid concentration under the condition of ensuring the same purification degree, reduce the energy consumption of post-treatment, and reduce the production cost.

[0011] Preferably, the washing water pipes are connected to a washing liquid tank. The washing liquid tanks connected to the subsequent multi-stage washing water pipes are equipped with liquid level controllers. The received filtrate is transported to the washing water spray holes of the previous stage through a circulation pump. A filter is arranged between the circulation pump and the washing water spray holes, and the washing water spray holes are installed at the top of the purification chamber.

[0012] Preferably, the conveying device is a conveying screw. In the present invention, a screw is arranged in the purification device, and at the same time, a sieve plate and a vacuum suction box are used for filtration and purification. On the basis of conventional horizontal belt pulp washing, the precipitation fiber can also be flipped, making the material dispersion more uniform, and the fiber is washed in a liquid form, avoiding the problem of needing to break and disperse the pulp due to high dryness.

[0013] Preferably, the gap between the conveying screw and the inner wall of the purification chamber is 0.5 - 3 mm, and the aperture of the sieve plate is 50 - 180 μm.

[0014] Preferably, the lower outlet of the vacuum suction box is connected to the middle of the gas-liquid separator through a pipeline. The lower part of the gas-liquid separator is connected to the top of the washing liquid tank, and the upper part of the gas-liquid separator is connected to the vacuum pump through a vacuum pipeline.

[0015] Preferably, the purification chamber is a cylindrical purification chamber, and the sieve plate is an arc-shaped sieve plate.

[0016] Under the same technical concept, the present invention also provides a purification process for a precipitation fiber purification device. Using the precipitation fiber purification device, precipitation fiber raw materials and washing liquid are added from the precipitation fiber pulp inlet, advanced by a screw, the gas-liquid separator controls the pressure of the vacuum suction box, and after being sprayed with recycled washing water for washing, wet purification is carried out to obtain washed fibers; the washing liquid flow rate of the washing water spray holes is 0.5 - 5m 3 / h, the screw propulsion speed is 1 - 5m / min, and the pressure of the vacuum suction box is -0.02 - -0.06MPa.

[0017] Preferably, the purified washed fibers are diluted with water in a dilution tank, and the dilution water flow rate is 2 - 4m 3 / h. After the material is diluted, it passes through a refiner and a pressure screen respectively to obtain a precipitation fiber dispersion liquid.

[0018] Preferably, the liquid level controller installed in the washing liquid tank connected to the subsequent multi-stage washing water pipeline controls the liquid level. When the liquid level exceeds 95%, it overflows, and when the liquid level is lower than 35%, pure water is replenished.

[0019] Under the same technical concept, the present invention also provides a precipitation fiber precipitation and purification device, including a precipitation fiber purification device. The precipitation fiber pulp inlet of the precipitation fiber purification device is connected to a multi-stage dispersion plate precipitation forming device. The multi-stage dispersion plate precipitation forming device includes a housing, a guiding component, a forming chamber, and a shaft. The inside of the housing is hollow to form a forming chamber, the shaft is arranged in the forming chamber, the guiding component is arranged at the inlet end of the forming chamber, and two dispersion plates are arranged in multiple stages in the forming chamber. The first-stage dispersion plate includes a shearing plate that can shear the material, and the second-stage dispersion plate includes a membrane-forming plate that can form a film on the material; the material flow path arranged in the forming chamber is arranged from the inlet end, through the dispersion plates arranged in multiple stages, and then to the outlet end in sequence. The dispersion plates are sleeved on the shaft; the shearing plate and the membrane-forming plate are coaxially sleeved and arranged opposite to each other up and down.

[0020] Preferably, the shearing plate includes a shearing plate stator and a shearing plate rotor. The shearing plate stator is fixedly connected to the inner wall of the housing, and the shearing plate rotor is fixedly connected to the shaft; the membrane-forming plate includes a membrane-forming plate stator and a membrane-forming plate rotor; the membrane-forming plate stator is fixedly connected to the inner wall of the housing, and the membrane-forming plate rotor is fixedly connected to the shaft.

[0021] Preferably, a resin spinneret assembly is provided on the housing. The resin spinneret assembly passes through the housing and the shear disc stator and maintains a certain gap with the shear disc rotor. There are multiple resin spinneret assemblies, which are evenly distributed on the shear disc stator. Multiple spinneret holes are evenly distributed on the panel of the resin spinneret assembly, and the aperture of the spinneret holes is 0.1 - 1.5 mm. The gap between the resin spinneret assembly and the shear disc rotor is 0.1 - 1.5 mm, and the gap between the shear disc stator and the shear disc rotor is 0.1 - 1.5 mm.

[0022] Preferably, the forming cavity sequentially includes a feeding channel, a shearing channel, a transition channel, a membrane-forming channel, and a discharging channel from top to bottom.

[0023] Preferably, the material flowing downward in the feeding channel diffuses to the periphery of the forming cavity to the shearing channel, the material flowing downward in the shearing channel diffuses to the middle of the forming cavity and is dispersed to the transition channel, and the material flowing downward in the transition channel enters the discharging channel after passing through the membrane-forming channel.

[0024] Preferably, the guiding component is a spiral rod. The spiral rod and multiple dispersing discs arranged in multiple stages are coaxially sleeved, and the bottom of the shaft is connected to the driving device through a transmission component.

[0025] The guiding component is a spiral rod. Combined with the flow channels designed in the forming cavity of the present application, during the transportation of the precipitation liquid, the fluid forms a regular and stable flow state. In terms of the design of the forming cavity, by changing the flow channel direction, the material is evenly dispersed in the forming cavity, which is beneficial to the uniformity of the product shape.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] (1) The present invention designs a purification device and process, which is a wet purification as a whole. It can keep the precipitation fibers at a relatively high humidity during the purification process. And through the cooperation of the screw, the sieve plate, and the vacuum suction water tank, the material has a turning action in the device, playing a stirring role, enabling the washing water to penetrate evenly in the material, improving the purification efficiency, and making the washing more uniform and thorough.

[0028] (2) The present invention is a wet purification process. During the purification process, the material always maintains a relatively high water content. After purification, it does not require secondary pulping, which can maximize the protection of the film-like structure from being damaged, contributing to the final preparation of film-like precipitation fibers. And the material with a relatively high water content can be directly connected to a dilution tank, a pressure pump, etc., simplifying the production process. Description of the Drawings

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0030] Figure 1 It is the flowchart for the preparation of the precipitated fiber in Example 1;

[0031] Figure 2 It is the schematic diagram of the purification device for the precipitated fiber in Example 1;

[0032] Figure 3 It is the cross-sectional schematic diagram of the purification chamber of the purification device for the precipitated fiber in Example 1;

[0033] Figure 4 It is the schematic diagram of the structure of the multi-stage dispersion disk precipitation forming device in Example 1;

[0034] Figure 5 It is the schematic diagram of the spinneret assembly of the multi-stage dispersion disk precipitation forming device in Example 1;

[0035] Figure 6 It is the scanning electron micrograph of the precipitated fiber.

[0036] In the figure: 1, the diversion component; 2, the forming cavity; 2-1, the feed channel; 2-2, the shear channel; 2-3, the transition channel; 2-4, the membrane-forming channel; 2-5, the discharge channel; 3, the shaft; 4, the resin spinneret assembly; 5, the shear disk stator; 6, the shear disk rotor; 7, the membrane-forming disk stator; 8, the membrane-forming disk rotor; 9, the spinneret hole; 10, the locking nut; 11, the precipitated fiber discharge port; 12, the precipitated fiber pulp distribution port; 13, the conveying screw; 14, the sieve plate; 15, the vacuum suction water tank; 16, the gas-liquid separator; 17, the purification chamber; 18, the washing liquid tank; 18-1, the first-stage washing liquid tank; 18-2, the second-stage washing liquid tank; 18-8, the eighth-stage washing liquid tank; 19, the vacuum pump; 20, the circulation pump; 21, the washing water spray hole; 22, the discharge port; 23, the filter; 24, the dilution tank; 25, the defibrator; 26, the conveying pump; 27, the pressure screen. Specific Embodiments

[0037] To facilitate the understanding of the present invention, the following will describe the present invention more comprehensively and meticulously in combination with the specification drawings and preferred embodiments, but the protection scope of the present invention is not limited to the following specific embodiments.

[0038] Unless otherwise defined, all technical terms used hereinafter have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the scope of the present invention.

[0039] Unless otherwise specifically stated, various raw materials, reagents, instruments, and equipment used in the present invention can be obtained through the market or prepared by existing methods.

[0040] Example 1:

[0041] The overall process steps refer to Figure 1 the precipitation fiber preparation flow chart. The precipitation fiber obtained by the multi-stage dispersion disk precipitation forming device enters the purification device together with the washing liquid from the precipitation fiber pulp inlet.

[0042] Forming process:

[0043] Adopt a multi-stage dispersion disk precipitation forming device, such as Figure 1 , 2 . The precipitation liquid is guided into the forming cavity 2 through the screw rod 1. The screw rod is fixed on the shaft 3 by threads; the upper shear disk in the forming cavity 2 is composed of a shear disk stator 5 and a shear disk rotor 6; the shear disk stator 5 is horizontally fixed on the shell of the forming cavity 2, and the shear disk rotor 6 is horizontally fixed on the shaft 3; the middle membrane forming disk in the forming cavity 2 is composed of a membrane forming disk stator 7 and a membrane forming disk rotor 8; the membrane forming disk stator 7 is horizontally fixed on the shell of the forming cavity 2, and the membrane forming disk rotor 8 is horizontally fixed on the shaft 3; the resin spinneret assembly 4 passes through the shell of the forming cavity 2 and maintains a certain gap with the shear disk stator 5 and the shear disk rotor 6, and is fixed by a locking nut 10; the lower part of the forming cavity 2 is the precipitation fiber outlet channel, and the tail end is the precipitation fiber discharge port 11. The bottom of the shaft 3 is connected to the driving motor through a belt.

[0044] The inside of the forming cavity 2 sequentially includes a feed channel 2-1, a shear channel 2-2, a transition channel 2-3, a membrane forming channel 2-4, and a discharge channel 2-5 from top to bottom. The material descending in the feed channel 2-1 diffuses to the periphery of the forming cavity 2 to the shear channel 2-2, and the material descending in the shear channel 2-2 diffuses to the middle of the forming cavity 2 and is dispersed to the transition channel 2-3. The material descending in the transition channel 2-3 enters the discharge channel 2-5 after passing through the membrane forming channel 2-4.

[0045] There are a total of 8 resin spinneret assemblies 4, which are evenly distributed on the shear disk stator 5. There are 8 spinneret holes 9 evenly distributed on the panel of the resin spinneret assembly 4, and the pore diameter is 0.1 - 1.5 mm. The gap between the resin spinneret assembly 4 and the shear disk rotor 6 is 0.1 - 1.5 mm, and the gap between the shear disk stator 5 and the shear disk rotor 6 is 0.1 - 1.5 mm.

[0046] The aperture of the spinneret holes is 0.5 mm, the gap between the resin spinneret plate assembly and the shear disc rotor is 0.5 mm, and the gap between the shear disc stator and the shear disc rotor is 0.5 mm. The flow rate of the precipitation liquid is 3 m 3 / h, and the total resin flow rate is 0.2 m 3 / h. The rotational speeds of both the shear disc rotor and the membrane-forming disc rotor are 2000 rpm. The content of DMAc in the precipitation liquid is 30%, the calcium chloride content is 1.2%, and the temperature of the precipitation liquid is 30°C. The solid content of the precipitated resin is 10%, and the resin temperature is 40°C.

[0047] A precipitation fiber purification device, as shown in Figure 3 、 4 , the pulp inlet 12 of the precipitation fiber is connected to the discharge outlet 11 of the precipitation fiber of the forming device. A conveying screw 13 is arranged inside the cylindrical purification chamber 17. An arc-shaped sieve plate 14 is arranged at the lower end of the purification chamber 17. The lower end of the sieve plate 14 is connected to a vacuum suction water tank 15. The water outlet at the lower end of the vacuum suction water tank is connected to the middle part of a gas-liquid separator 16 through a pipeline. The lower part of the gas-liquid separator is connected to the top of a washing liquid tank 18, and the upper part of the gas-liquid separator is connected to a vacuum pump 19 through a vacuum pipeline.

[0048] The washing water pipelines are connected in an 8-stage countercurrent manner. The filtrate received by the 1st-stage washing liquid tank 18-1 is transported to the solvent recovery system. The filtrate received by the 2nd-stage washing liquid tank 18-2 is transported to the solvent recovery system, and so on until the filtrate received by the 8th-stage washing liquid tank 18-8 is transported to the solvent recovery system. The filtrate received by the 2nd to 8th-stage washing liquid tanks is transported to the washing water spray holes 21 of the previous stage through a circulation pump 20. There is a filter 23 between the circulation pump 20 and the washing water spray holes 21. The washing water spray holes 21 are installed at the top of the purification chamber 17, and the 8th-stage spray holes are externally connected to pure water.

[0049] There is a discharge outlet 22 at the tail of the purification chamber 17. The discharge outlet 22 is connected to a dilution tank 24 through a pipeline. The dilution tank 24 is equipped with a stirring device and is connected to a defibrator 25 through a delivery pump 26. The defibrator is connected to a pressure screen 27 through a pipeline.

[0050] The gap between the conveying screw 13 and the inner wall of the purification chamber 17 is 0.5 - 3 mm, and the aperture of the sieve plate 14 is 50 - 180 μm.

[0051] The 2nd to 8th-stage washing liquid tanks are equipped with liquid level controllers. When the liquid level is too high, it overflows, and when the liquid level is too low, pure water is replenished.

[0052] A purification process for a precipitation fiber purification device:

[0053] Purification: Using the precipitation fiber purification device described in this embodiment, the gap between the conveying screw and the inner wall of the purification chamber 12 is 1 mm, and the aperture of the sieve plate is 120 μm. The washing liquid flow rate of the washing water spray holes is 1 m 3 / h, the screw propulsion speed is 2 m / min, and the pressure of the vacuum suction box is -0.03 MPa. The material is diluted with water in the dilution tank, and the dilution water flow rate is 4 m 3 / h. After the material is diluted, it passes through a defibrator and a pressure screen respectively to obtain a precipitated fiber dispersion liquid.

[0054] The large specific surface area precipitated fibers obtained by the above precipitated fiber preparation process, the length, width, beating degree, specific surface area, DMAc absolute dry equivalent, and chlorine element absolute dry equivalent are shown in Table 1.

[0055] Figure 6 This is the scanning electron microscope image of the precipitated fibers. It can be clearly seen from the figure that the precipitated fibers are in the form of thin films, large and thin. This structure can strengthen the entanglement and bonding of the chopped fibers and improve the mechanical properties of aramid paper.

[0056] Example 2

[0057] A purification process of a precipitated fiber purification device:

[0058] Forming: A multi-stage dispersion disk precipitation forming device is used. The aperture of the spinneret hole is 0.5 mm, the gap between the resin spinneret plate and the shear disk rotor is 1 mm, and the gap between the shear disk stator and the shear disk rotor is 1 mm. The precipitation liquid flow rate is 3 m 3 / h, the total resin flow rate is 0.2 m 3 / h. The rotation speeds of the shear disk rotor and the membrane forming disk rotor are both 2000 rpm. The DMAc content of the precipitation liquid is 30%, the calcium chloride content is 1.2%, and the temperature of the precipitation liquid is 30 °C. The solid content of the precipitation resin is 10%, and the resin temperature is 40 °C.

[0059] Purification: The precipitated fiber purification device described in Example 1 is used. The gap between the conveying screw and the inner wall of the purification chamber 17 is 1 mm, and the aperture of the sieve plate is 120 μm. The washing liquid flow rate of the washing water spray holes is 1 m 3 / h, the screw propulsion speed is 2 m / min, and the pressure of the vacuum suction box is -0.03 MPa. The material is diluted with water in the dilution tank, and the dilution water flow rate is 4 m 3 / h. After the material is diluted, it passes through a defibrator and a pressure screen respectively to obtain a precipitated fiber dispersion liquid.

[0060] Example 3

[0061] Forming: A multi-stage dispersion disk precipitation forming device is used. The aperture of the spinneret hole is 0.5 mm, the gap between the resin spinneret plate and the shear disk rotor is 0.5 mm, and the gap between the shear disk stator and the shear disk rotor is 0.5 mm. The precipitation liquid flow rate is 3 m 3 / h, the total resin flow rate is 0.2 m 3 / h. The rotational speeds of both the shearing disk rotor and the membrane-forming disk rotor are 3000 rpm. The content of DMAc in the precipitation liquid is 30%, the content of calcium chloride is 1.2%, and the temperature of the precipitation liquid is 30°C. The solid content of the precipitated resin is 10%, and the resin temperature is 40°C.

[0062] Purification: Using the precipitation fiber purification device described in Example 1, the gap between the conveying screw and the inner wall of the purification chamber 17 is 1 mm, and the aperture of the sieve plate is 120 μm. The washing liquid flow rate of the washing water spray holes is 1 m 3 / h, the screw propulsion speed is 2 m / min, and the pressure of the vacuum suction water tank is -0.03 MPa. The material is diluted with water in the dilution tank, and the dilution water flow rate is 4 m 3 / h. After the material is diluted, it passes through a defibrator and a pressure screen respectively to obtain a dispersion of precipitated fibers.

[0063] Example 4

[0064] Forming: Using a multi-stage dispersion disk precipitation forming device, the aperture of the spinneret holes is 0.5 mm, the gap between the resin spinneret plate and the shearing disk rotor is 0.5 mm, and the gap between the shearing disk stator and the shearing disk rotor is 0.5 mm. The precipitation liquid flow rate is 4 m 3 / h, the total resin flow rate is 0.3 m 3 / h. The rotational speeds of both the shearing disk rotor and the membrane-forming disk rotor are 2000 rpm. The content of DMAc in the precipitation liquid is 30%, the content of calcium chloride is 1.2%, and the temperature of the precipitation liquid is 30°C. The solid content of the precipitated resin is 6%, and the resin temperature is 40°C.

[0065] Purification: Using the precipitation fiber purification device of Example 1, the gap between the conveying screw and the inner wall of the purification chamber 17 is 1 mm, and the aperture of the sieve plate is 120 μm. The washing liquid flow rate of the washing water spray holes is 1 m 3 / h, the screw propulsion speed is 2 m / min, and the pressure of the vacuum suction water tank is -0.03 MPa. The material is diluted with water in the dilution tank, and the dilution water flow rate is 4 m 3 / h. After the material is diluted, it passes through a defibrator and a pressure screen respectively to obtain a dispersion of precipitated fibers.

[0066] Example 5

[0067] Forming: Using a multi-stage dispersion disk precipitation forming device, the aperture of the spinneret holes is 0.5 mm, the gap between the resin spinneret plate and the shearing disk rotor is 0.5 mm, and the gap between the shearing disk stator and the shearing disk rotor is 0.5 mm. The precipitation liquid flow rate is 3 m 3 / h, the total resin flow rate is 0.2 m 3 / h. The rotational speeds of both the shearing disk rotor and the membrane-forming disk rotor are 2000 rpm. The content of DMAc in the precipitation liquid is 30%, the content of calcium chloride is 1.2%, and the temperature of the precipitation liquid is 30°C. The solid content of the precipitated resin is 10%, and the resin temperature is 40°C.

[0068] Purification: Using the precipitation fiber purification device of Example 1, the gap between the conveying screw and the inner wall of the purification chamber 17 is 1 mm, and the aperture of the sieve plate is 120 μm. The washing liquid flow rate of the washing water spray holes is 1.5 m 3 / h, the screw propulsion speed is 2 m / min, and the pressure of the vacuum suction water tank is -0.03 MPa. The material is diluted with water in the dilution tank, and the dilution water flow rate is 4 m 3 / h. After the material is diluted, it passes through a refiner and a pressure screen respectively to obtain a precipitation fiber dispersion liquid.

[0069] Comparative Example 1

[0070] Forming: Using a multi-stage dispersion disk precipitation forming device, the aperture of the spinneret holes is 0.5 mm, the gap between the resin spinneret plate and the shear disk rotor is 0.5 mm, and the gap between the shear disk stator and the shear disk rotor is 0.5 mm. The precipitation liquid flow rate is 3 m 3 / h, the total resin flow rate is 0.2 m 3 / h, and the rotational speeds of both the shear disk rotor and the membrane-forming disk rotor are 2000 rpm. The DMAc content of the precipitation liquid is 30%, the calcium chloride content is 1.2%, and the precipitation liquid temperature is 30 °C. The solid content of the precipitated resin is 10%, and the resin temperature is 40 °C.

[0071] Purification: Using intermittent pulp washing, the formed material is centrifuged, and the dryness after centrifugation is 12%. The filter cake is put into a pulper and pulped for 10 min, and the pulping concentration is 1%. After pulping, it is centrifuged again, and this washing process is repeated 4 times.

[0072] Comparative Example 2

[0073] Forming: Using a multi-stage dispersion disk precipitation forming device, the aperture of the spinneret holes is 0.5 mm, the gap between the resin spinneret plate and the shear disk rotor is 0.5 mm, and the gap between the shear disk stator and the shear disk rotor is 0.5 mm. The precipitation liquid flow rate is 3 m 3 / h, the total resin flow rate is 0.2 m 3 / h, and the rotational speeds of both the shear disk rotor and the membrane-forming disk rotor are 2000 rpm. The DMAc content of the precipitation liquid is 30%, the calcium chloride content is 1.2%, and the precipitation liquid temperature is 30 °C. The solid content of the precipitated resin is 10%, and the resin temperature is 40 °C.

[0074] Purification: Using the precipitation fiber purification device of Example 1, the gap between the conveying screw and the inner wall of the purification chamber 17 is 1 mm, and the aperture of the sieve plate is 120 μm. The washing liquid flow rate of the washing water spray holes is 1 m 3 / h, the screw propulsion speed is 2 m / min, and the pressure of the vacuum suction water tank is -0.03 MPa. The material is diluted with water in the dilution tank, and the dilution water flow rate is 4 m 3 / h. After the material is diluted, it does not pass through a refiner and directly passes through a pressure screen to obtain a precipitation fiber dispersion liquid.

[0075] Comparative Example 3

[0076] Forming: A multi-stage dispersion disk precipitation forming device is used. The aperture of the spinneret holes is 0.5 mm, the gap between the resin spinneret plate and the shear disk rotor is 0.5 mm, and the gap between the shear disk stator and the shear disk rotor is 0.5 mm. The flow rate of the precipitation liquid is 3 m 3 / h, and the total resin flow rate is 0.2 m 3 / h. The rotational speeds of both the shear disk rotor and the membrane-forming disk rotor are 2000 rpm. The DMAc content of the precipitation liquid is 30%, the calcium chloride content is 1.2%, and the temperature of the precipitation liquid is 30 °C. The solid content of the precipitated resin is 10%, and the resin temperature is 40 °C.

[0077] Purification: The precipitation fiber purification device of Example 1 is used. The gap between the conveying screw and the inner wall of the purification chamber 17 is 1 mm, and the aperture of the sieve plate is 120 μm. The washing liquid flow rate of the washing water spray holes is 1 m 3 / h, the screw propulsion speed is 2 m / min, and the pressure of the vacuum suction water tank is -0.03 MPa. The material is diluted with water in the dilution tank, and the dilution water flow rate is 4 m 3 / h. After the material is diluted, it passes through a refiner and does not pass through a pressure screen, obtaining a dispersion of precipitated fibers.

[0078] Table 1. Comparison of the properties of precipitated fibers in examples and comparative examples

[0079]

[0080] Analysis in combination with Table 1 shows that: The precipitated fibers prepared by the present invention have a high beating degree, specific surface area, and water content. Using the precipitation fiber purification device and process described in the present invention, the solvent content and the contents of chlorine, calcium, and iron elements in the precipitated fibers are low, meeting the requirements for use in aramid paper. The refining and screening also have a great influence on the specific surface area, indicating that the refining and screening processes after purification are also necessary.

Claims

1. A precipitation fiber precipitation and purification device, characterized in that, It includes a precipitation fiber purification device, which includes a precipitation fiber slurry feeding port (12), a purification chamber (17), a conveying device, and a discharge port (22). The precipitation fiber slurry feeding port (12) is arranged at the head of the purification chamber (17), and the discharge port (22) is arranged at the tail of the purification chamber (17). The conveying device is installed in the purification chamber (17). It is characterized in that there is a discharge port (22) at the tail of the purification chamber (17), and the discharge port (22) is connected to a dilution tank (24) through a pipeline. The dilution tank (24) is equipped with a stirring device and is connected to a defibrator (25) through a delivery pump (26). The defibrator is connected to a pressure screen (27) through a pipeline; the conveying device installed in the purification chamber (17) conveys the unprecipitated precipitation fiber from the precipitation fiber slurry feeding port (12) to the discharge port (22), and continuously sprays and washes the precipitation fiber during the conveying process. There are washing water spray holes (21) for spraying and washing and a spray washing water recycling system in the purification chamber (17). The precipitation fiber slurry feeding port (12) of the precipitation fiber purification device is connected to a multi-stage dispersion disk precipitation forming device, and the multi-stage dispersion disk precipitation forming device includes a housing, a guiding component (1), a forming chamber (2), and a shaft (3). The inside of the housing is hollow to form the forming chamber (2), and the shaft (3) is arranged in the forming chamber (2). The guiding component (1) is arranged at the inlet end of the forming chamber (2). There are two dispersion disks arranged in multiple stages in the forming chamber (2). The first-stage dispersion disk includes a shearing disk that can shear the material, and the second-stage dispersion disk includes a membrane-forming disk that can form a film on the material; the material flow channel arranged in the forming chamber (2) is arranged in sequence from the inlet end, through the dispersion disks arranged in multiple stages, and then to the outlet end. The dispersion disks are sleeved on the shaft (3); the shearing disk and the membrane-forming disk are coaxially sleeved and arranged opposite to each other up and down.

2. The precipitation fiber precipitation and purification device according to claim 1, characterized in that, The shearing disk includes a shearing disk stator (5) and a shearing disk rotor (6). The shearing disk stator (5) is fixedly connected to the inner wall of the housing, and the shearing disk rotor (6) is fixedly connected to the shaft (3); the membrane-forming disk includes a membrane-forming disk stator (7) and a membrane-forming disk rotor (8); the membrane-forming disk stator (7) is fixedly connected to the inner wall of the housing, and the membrane-forming disk rotor (8) is fixedly connected to the shaft (3).

3. The precipitation fiber precipitation and purification device according to claim 2, characterized in that, A resin spinneret plate assembly (4) is arranged on the housing. The resin spinneret plate assembly (4) passes through the housing and keeps a certain gap from the shearing disk rotor (6); there are multiple resin spinneret plate assemblies (4), which are evenly distributed on the shearing disk stator (5). Multiple spinneret holes (9) are evenly distributed on the panel of the resin spinneret plate assembly (4), and the aperture is 0.1 - 1.5 mm; the gap between the resin spinneret plate assembly (4) and the shearing disk rotor (6) is 0.1 - 1.5 mm, and the gap between the shearing disk stator (5) and the shearing disk rotor (6) is 0.1 - 1.5 mm.

4. The precipitation fiber precipitation and purification device according to any one of claims 1-3, characterized in that, Inside the forming chamber (2), from top to bottom, it sequentially includes a feeding channel (2-1), a shearing channel (2-2), a transition channel (2-3), a membrane-forming channel (2-4), and a discharging channel (2-5).

5. The precipitation fiber precipitation and purification device according to claim 4, characterized in that, The material flowing downward in the feeding channel (2-1) diffuses to the periphery of the forming cavity (2) and then enters the shearing channel (2-2). The material flowing downward in the shearing channel (2-2) diffuses to the middle of the forming cavity (2) and is dispersed into the transition channel (2-3). The material flowing downward in the transition channel (2-3) enters the discharge channel (2-5) after passing through the membrane-forming channel (2-4).

6. The precipitation fiber precipitation and purification device according to any one of claims 1-3, characterized in that, The guiding component (1) is a screw rod. The screw rod and multiple dispersing disks arranged in multiple stages are coaxially sleeved. The bottom of the shaft (3) is connected to the driving device through a transmission component.

7. The precipitation fiber precipitation and purification device according to claim 1, characterized in that, The spray washing water recycling system includes a sieve plate (14) arranged at the lower end of the purification cavity (17) and a vacuum suction water tank (15) connected to the lower end of the sieve plate (14). The water outlet at the lower end of the vacuum suction water tank (15) is connected to the gas-liquid separator (16) through a washing water pipe. The filtrate outlet of the gas-liquid separator (16) is communicated with the washing water spray holes (21).

8. The precipitation fiber precipitation and purification device according to claim 7, characterized in that The washing water pipes are connected in a multi-stage countercurrent manner. The filtrate received by the first-stage washing water pipe is transported to the solvent recovery system. The filtrates received by the subsequent multi-stage washing water pipes are transported to the washing water spray holes (21) of the previous stage. The washing water spray holes (21) of the last stage are externally connected to pure water.

9. The precipitation fiber precipitation and purification device according to claim 8, characterized in that, The washing water pipes are connected to the washing liquid tank (18). The washing liquid tanks (18) connected by the subsequent multi-stage washing water pipes are equipped with liquid level controllers. The received filtrate is transported to the washing water spray holes (21) of the previous stage through a circulating pump (20). A filter is arranged between the circulating pump (20) and the washing water spray holes (21). The washing water spray holes (21) are installed at the top of the purification cavity (17).

10. The precipitation fiber precipitation and purification device according to claim 7, characterized in that, The conveying device is a conveying screw rod (13).

11. The precipitation fiber precipitation and purification device according to claim 10, characterized in that, The gap between the conveying screw rod (13) and the inner wall of the purification cavity (17) is 0.5 - 3 mm, and the aperture of the sieve plate (14) is 50 - 180 μm.

12. The precipitation fiber precipitation and purification device according to claim 7, characterized in that, The water outlet at the lower end of the vacuum suction water tank (15) is connected to the middle of the gas-liquid separator (16) through a pipe. The lower part of the gas-liquid separator (16) is connected to the top of the washing liquid tank (18). The upper part of the gas-liquid separator (16) is connected to a vacuum pump (19) through a vacuum pipe.

13. The precipitation fiber precipitation and purification device according to claim 7, characterized in that, The purification cavity (17) is a cylindrical purification cavity, and the sieve plate (14) is an arc-shaped sieve plate.

14. A purification process for precipitated fibers, characterized in that, Using the precipitation fiber precipitation and purification device according to any one of claims 1-13, add precipitation fiber raw materials and washing liquid from the precipitation fiber pulp inlet (12), propel with a screw, the gas-liquid separator (16) controls the pressure of the vacuum suction water tank (15), and after spray washing water is recycled for washing, wet purification is carried out to obtain washed fibers; the washing liquid flow rate of the washing water spray holes is 0.5~5m 3 / h, the screw propulsion speed is 1~5m / min, and the pressure of the vacuum suction water tank (15) is -0.02~-0.06MPa.

15. The purification process according to claim 14, wherein, The purified washed fiber is diluted with water in a dilution tank (24), and the dilution water flow rate is 2 - 4 m 3 / h. After dilution of the material, it passes through a refiner (25) and a pressure screen (27) respectively to obtain a precipitated fiber dispersion liquid.

16. The purification process according to claim 14, wherein The liquid level controllers installed in the washing liquid tanks (18) connected by the subsequent multi-stage washing water pipes control the liquid level. When the liquid level exceeds 95%, it overflows. When the liquid level is lower than 35%, pure water is replenished.

Images