Nylon 66 chip cooling and aqueous homogenization system and control process

Abstract

The present application belongs to the technical field of nylon 66 chip drying, and discloses a nylon 66 chip cooling and water content homogenizing system and a control process thereof, which solves the problems of high energy consumption, large temperature difference between the inside and outside of the chip, and uneven water content rate of the existing single-stage cooling mode of high-temperature chip. The system comprises a cooling homogenizing tower, a dust collector, a fan, a cooler, a humidifying metering pump and the like. The cooling homogenizing tower is divided into three sections, i.e. upper, middle and lower sections. Each section is provided with a nitrogen distributor and a temperature monitoring point. The temperature, humidity, pressure and flow of nitrogen are controlled in sections to realize the segmented cooling and water content homogenization of the chip. The method comprises: the chip flows from top to bottom, and forms countercurrent heat exchange with nitrogen flowing from bottom to top. The temperature of the upper section and the middle section is controlled by adjusting the mixing ratio of uncooled nitrogen and cooled nitrogen. The lower section adopts constant-temperature, constant-humidity and constant-flow nitrogen for water content homogenization. The present application effectively improves the cooling uniformity and water content consistency of the chip, and reduces the energy consumption.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of nylon 66 chip drying, and particularly relates to a nylon 66 chip cooling and water content homogenization system and a control process thereof. BACKGROUND

[0002] In the production of nylon 66 fibers, chip drying is a key process. In the prior art, the high-temperature chip (80-110 DEG C) treated by the drying tower is usually cooled in a single stage, and problems such as low cooling efficiency, high energy consumption, large temperature difference between the inside and outside of the chip, and uneven water content exist. Moreover, the humidity of the cooling medium lacks precision control, which further aggravates the uneven water content. This directly leads to unstable product quality in the subsequent spinning process and large performance fluctuations of the finished yarn. Therefore, a technology and system capable of realizing efficient and uniform cooling and water content homogenization are urgently needed. SUMMARY

[0003] One object of the application is to provide a nylon 66 chip cooling and water content homogenization system, which effectively solves the problems of high energy consumption, large temperature difference between the inside and outside of the chip, and uneven water content existing in the single-stage cooling mode of the existing high-temperature chip.

[0004] To solve the above technical problems, the application adopts the technical scheme of a nylon 66 chip cooling and water content homogenization system, which comprises a PLC controller, a cooling homogenization tower, a dust collector, a fan, a cooler, a humidifying metering pump, a water-gas mixer, and matched pressure, temperature, dew point, and flow detection instruments and regulating valves. The PLC controller automatically adjusts the frequency of the fan and the flow of the humidifying metering pump according to the feedback of the detection instruments.

[0005] The cooling homogenization tower is provided with a chip inlet and a nitrogen gas outlet at the top and a chip outlet at the bottom. The tower body is sequentially divided into an upper section, a middle section, and a lower section from top to bottom, and each section of the tower body is provided with a group of thermometers and a nitrogen gas distributor. A thermometer for monitoring the temperature of the chip outlet is arranged at the bottom of the tower body.

[0006] The inlet of the fan is connected with the nitrogen gas outlet through the dust collector. The outlet of the fan is divided into three paths: the first path is connected with a first-stage cooling pipeline, the outlet of the first-stage cooling pipeline is connected with the nitrogen gas distributor located in the upper section of the tower body; the second path is connected with a second-stage cooling pipeline, the outlet of the second-stage cooling pipeline is connected with the nitrogen gas distributor located in the middle section of the tower body; and the third path is connected with the inlet of the cooler. The outlet of the cooler is connected with the first inlet of the water-gas mixer. The second inlet of the water-gas mixer is connected with the outlet of the humidifying metering pump. The inlet of the humidifying metering pump is connected with a pure water tank. The outlet of the water-gas mixer is connected with a cooling homogenization pipeline. The outlet of the cooling homogenization pipeline is connected with the nitrogen gas distributor located in the lower section of the tower body.

[0007] Further, a pressure gauge, a thermometer and a dew point meter are arranged on the connecting pipeline between the nitrogen outlet of the cooling and homogenizing tower and the inlet of the dust remover, a pressure gauge and a nitrogen supplement valve are arranged on the connecting pipeline between the outlet of the dust remover and the inlet of the fan, the first-stage cooling pipeline and the second-stage cooling pipeline are both provided with an adjusting valve for adjusting the nitrogen inlet amount, the inlet pipeline of the cooler is provided with a vent valve, and the cooling and homogenizing pipeline is provided with a dew point meter, a flow meter, a pressure gauge and a thermometer.

[0008] Further, three thermometers are arranged in the upper section, the middle section and the lower section of the tower body, and the three thermometers are uniformly distributed at the same height of the tower body.

[0009] Further, the cooling and homogenizing tower is a stainless steel cylindrical structure, the inner wall of the cooling and homogenizing tower is polished, and the height ratio of the upper section, the middle section and the lower section of the tower body is 1:1:2.

[0010] Further, the nitrogen distributor adopts a horn barrel structure, the dust remover is a bag reverse blowing dust remover, the fan is a Roots fan, the cooler is a tube type cooler, the flow meter is a vortex flow meter, and the humidifying metering pump is a diaphragm pump.

[0011] Further, the tower body of the cooling and homogenizing tower is provided with a continuous material level meter for monitoring the slice level in the tower.

[0012] Another object of the present application is to provide a control process of the nylon 66 slice cooling and water-containing homogenizing system as described in the above embodiments, when the high-temperature slice of 80-100 DEG C enters the cooling and homogenizing tower, the slice flows from top to bottom; the cold nitrogen enters from the lower part of the cooling and homogenizing tower and flows out from the top, and forms a convection with the slice; the nitrogen flowing out from the top of the cooling and homogenizing tower is filtered by the dust remover and enters the fan, and the nitrogen at the outlet of the fan is divided into three paths: the first path of the uncooled nitrogen is sent to the upper section of the cooling and homogenizing tower, is mixed with the cold nitrogen coming from below through the nitrogen distributor, and the temperature of the upper section is maintained at 60-70 DEG C; the second path of the uncooled nitrogen is sent to the middle section of the cooling and homogenizing tower, is mixed with the cold nitrogen coming from below through the nitrogen distributor, and the temperature of the middle section is maintained at 35-45 DEG C; the third path of the nitrogen is cooled to 20-30 DEG C through the cooler, and then the dew point of the third path of the nitrogen is controlled at-15 DEG C through the linkage of the humidifying metering pump and the vent valve on the inlet pipeline of the cooler, and the third path of the nitrogen is sent to the nitrogen distributor of the lower section of the cooling and homogenizing tower and enters the homogenization of the slice.

[0013] Further, the pressure of the system is maintained at 10±5 kPa, and the apparent flow velocity of the nitrogen in the cooling and homogenizing tower is 0.2 m / s.

[0014] Compared with the prior art, the present application has the beneficial technical effects that: (1) the cooling and homogenizing tower of the present application realizes the functional zoning of "pre-cooling in the upper section, deep cooling in the middle section, and homogenization in the lower section" through airflow regulation instead of physical separation, and has compact structure and smooth process flow.

[0015] (2) The slices in the cooling and homogenizing tower flow from top to bottom and are countercurrently contacted with the cold nitrogen gas flowing from bottom to top, so that the heat exchange efficiency is high. By splitting the circulating nitrogen gas, only part of the nitrogen gas needs to be deeply cooled, which greatly reduces the refrigeration energy consumption of the system.

[0016] (3) The present application introduces the nitrogen gas that has been cooled and precisely humidified into the lower section of the cooling and homogenizing tower, thereby providing a stable and reliable homogenization environment for the slices, effectively eliminating the moisture content gradient between the slices, and improving the cooling uniformity and moisture content consistency of the slices.

[0017] (4) The present application controls multiple parameters such as temperature, pressure, flow rate, and dew point based on the PLC controller, ensuring the stability of the process and the consistency of the product, and improving the production efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a connection structure diagram of the nylon 66 slice cooling and moisture homogenization system of the present application, and the arrows in the figure represent the flow direction of the medium in the pipeline.

[0019] BRIEF DESCRIPTION OF DRAWINGS: cooling and homogenizing tower-1; dust collector-2; fan-3; cooler-4; humidifying metering pump-5; water-gas mixer-6; slice inlet-7; nitrogen gas outlet-8; slice outlet-9; upper section thermometer-10; first nitrogen gas distributor-11; middle section thermometer-12; second nitrogen gas distributor-13; lower section thermometer-14; third nitrogen gas distributor-15; bottom thermometer-16; first pressure gauge-17; first thermometer-18; first dew point meter-19; second pressure gauge-20; nitrogen gas supplement valve-21; pure water tank-22; regulating valve-23; vent valve-24; second dew point meter-25; flow meter-26; third pressure gauge-27; second thermometer-28. DETAILED DESCRIPTION

[0020] Example 1: The present embodiment provides a nylon 66 slice cooling and moisture homogenization system, as shown in Figure 1 , which comprises a PLC controller, a cooling and homogenizing tower 1, a dust collector 2, a fan 3, a cooler 4, a humidifying metering pump 5, a water-gas mixer 6, and matching pressure, temperature, dew point, and flow rate detection instruments and regulating valves. The system automatically adjusts the valves, the frequency of the fan 3, and the flow rate of the humidifying metering pump 5 according to the feedback of the detection instruments through the PLC controller, thereby realizing precise control of the state of the three-section nitrogen gas (mixed temperature control in the upper and middle sections, and constant temperature and humidity control in the lower section).

[0021] In this embodiment, the cooling homogenization tower 1 is a stainless steel cylindrical structure with a polished inner wall (Ra≤0.8). The top of the cooling homogenization tower 1 has a slice inlet 7 for feeding high-temperature (80-100℃) slices into the tower and a nitrogen outlet 8, while the bottom has a slice outlet 9 for discharging the cooled and homogenized slices out. The tower body of the cooling homogenization tower 1 is divided into an upper section, a middle section, and a lower section from top to bottom, with a height ratio of 1:1:2 to match the required residence time of the slices in each section (e.g., approximately 3 hours in the upper and middle sections, and approximately 6 hours in the lower section).

[0022] The upper section of the tower is equipped with a set of three upper-section thermometers 10, evenly distributed at the same height. A first nitrogen distributor 11 with a trumpet-shaped structure is also located within the upper section, connected to the first-stage cooling pipe for introducing uncooled high-temperature nitrogen. The middle section of the tower is equipped with a set of three middle-section thermometers 12 and a second nitrogen distributor 13 with a trumpet-shaped structure, also evenly distributed at the same height. The second nitrogen distributor 13 is connected to the second-stage cooling pipe for introducing uncooled high-temperature nitrogen. Similarly, the lower section of the tower is equipped with a set of three lower-section thermometers 14 and a third nitrogen distributor 15 with a trumpet-shaped structure, also evenly distributed at the same height. The third nitrogen distributor 15 is connected to a cooling homogenization pipe for introducing cooled, low-temperature nitrogen. A bottom thermometer 16 is installed at the bottom of the tower to monitor the temperature of the slices exiting the tower. A continuous level gauge is installed in the tower to monitor the level of the slices inside the tower.

[0023] The nitrogen outlet 8 at the top of the cooling homogenization tower 1 is connected to the inlet of the dust collector 2 to remove dust generated during the slicing cooling process. A first pressure gauge 17, a first thermometer 18, and a first dew point meter 19 are installed on the connecting pipe between the nitrogen outlet 8 of the cooling homogenization tower 1 and the inlet of the dust collector 2 to monitor the pressure, temperature, and dew point at the outlet of the tower. The outlet of the dust collector 2 is connected to the inlet of the fan 3. A second pressure gauge 20 and a nitrogen inlet valve 21 are installed on the connecting pipe between the outlet of the dust collector 2 and the inlet of the fan 3 to monitor the system pressure and to allow for nitrogen inlet.

[0024] The outlet of the fan 3 is divided into three paths: the first path is connected to the first stage cooling pipeline, the outlet of the first stage cooling pipeline is connected to the first nitrogen distributor 11 located at the upper section of the tower body; the second path is connected to the second stage cooling pipeline, the outlet of the second stage cooling pipeline is connected to the second nitrogen distributor 13 located at the middle section of the tower body; the third path is connected to the inlet of the cooler 4, the outlet of the cooler 4 is connected to the first inlet of the water-gas mixer 6 for water-gas mixing, the second inlet of the water-gas mixer 6 is connected to the outlet of the humidification metering pump 5 for system humidification, the inlet of the humidification metering pump 5 is connected to the pure water tank 22, and the outlet of the water-gas mixer 6 is connected to the cooling and homogenizing pipeline, and the outlet of the cooling and homogenizing pipeline is connected to the third nitrogen distributor 15 located at the lower section of the tower body. The fan 3 is used to provide power for nitrogen circulation.

[0025] The first stage cooling pipeline and the second stage cooling pipeline are each provided with an adjusting valve 23 for adjusting the nitrogen inlet amount; the inlet pipeline of the cooler 4 is provided with a vent valve 24 for adjusting the system pressure and humidity; and the cooling and homogenizing pipeline is provided with a second dew point instrument 25, a flow meter 26, a third pressure gauge 27 and a second temperature gauge 28 for monitoring the temperature, humidity, pressure and flow of the cooling and homogenizing gas.

[0026] In the embodiment, the dust remover 2 is a bag reverse-blowing dust remover, the fan 3 is a Roots blower, the cooler 4 is a tube-type cooler, the flow meter 26 is a vortex flow meter, and the humidification metering pump 5 is a diaphragm pump.

[0027] The control process of the embodiment is as follows: (1) when the high-temperature slice at 80-100℃ enters the cooling and homogenizing tower 1, it slowly flows from top to bottom; the cold nitrogen enters from the lower part of the cooling and homogenizing tower 1 and flows out from the top, forming convection with the slice.

[0028] (2) The nitrogen gas flowing out from the top of the cooling and homogenizing tower 1 is filtered by the dust remover 2, enters the fan 3, and the fan 3 provides power for nitrogen circulation.

[0029] The nitrogen gas from the outlet of the fan 3 is divided into three paths: the first path of the nitrogen gas without cooling is sent to the upper section of the cooling and homogenizing tower 1, and mixed with the cold nitrogen gas from below through the first nitrogen gas distributor 11. The temperature meter group of the upper section takes the average of the detected temperature, and then adjusts the valve opening degree through the PLC controller to meet the temperature setting requirement of the upper section (the temperature of the upper section is maintained at 60-70°C). The second path of the nitrogen gas without cooling is sent to the middle section of the cooling and homogenizing tower 1, and mixed with the cold nitrogen gas from below through the second nitrogen gas distributor 13. The temperature meter group of the middle section takes the average of the detected temperature, and then adjusts the valve opening degree through the PLC controller to meet the temperature setting requirement of the middle section (the temperature of the middle section is maintained at 35-45°C). The third path of the nitrogen gas is cooled to 20-30°C through the cooler 4, and then the dew point of the third path of the nitrogen gas is controlled at about -15°C through the linkage of the humidifying metering pump 5 and the vent valve 24, and is sent to the third nitrogen gas distributor 15 of the lower section of the cooling and homogenizing tower 1 to enter the water-containing homogenization of the slice.

[0030] The temperature of the second temperature meter 28 on the cooling and homogenizing pipeline can be adjusted by adjusting the valve opening degree of the pipeline cooling water of the cooler 4. The flow rate of the flow meter 26 can be adjusted by adjusting the frequency of the fan 3. The dew point of the second dew point instrument 25 can be adjusted by the humidifying metering pump 5 and the vent valve 24, and the vent valve 24 is opened when the dew point temperature is high, and the humidifying metering pump 5 is started to humidify when the dew point temperature is low. The pressure of the second pressure gauge 20 is adjusted through the nitrogen gas supplement valve 21 and the vent valve 24. The pressure difference between the first pressure gauge 17 and the third pressure gauge 27 can monitor the flow condition in the tower, and the pressure difference between the first pressure gauge 17 and the second pressure gauge 20 can reflect the blockage condition of the dust remover 2.

[0031] The whole system is automatically controlled by the PLC, and the degree of automation is high. Specifically, ① for the control of the upper section of the cooling and homogenizing tower 1: the uncooled nitrogen gas is mixed by adjusting the regulating valve 23 of the first stage cooling pipeline to maintain the temperature of the upper section at 60-70°C. ② for the control of the middle section of the cooling and homogenizing tower 1: the uncooled nitrogen gas is mixed by adjusting the regulating valve 23 of the second stage cooling pipeline to maintain the temperature of the middle section at 35-45°C. ③ for the control of the lower section of the cooling and homogenizing tower 1: the third path of the nitrogen gas is cooled to 20-30°C through the cooler 4, and then the dew point thereof is accurately controlled at about -15°C through the linkage of the humidifying metering pump 5 and the vent valve 24 to homogenize the slice in a constant state. ④ for the system pressure: the system pressure is maintained at 10±5kPa through the nitrogen gas supplement valve 21 and the vent valve 24. ⑤ for the nitrogen gas flow rate: the frequency of the fan 3 is adjusted to ensure that the apparent flow rate of the nitrogen gas in the tower is about 0.2m / s. ⑥ for the dew point temperature: the humidity of the nitrogen gas entering the lower part of the tower is adjusted to control the range of -15°C, and the humidifying metering pump 5 is started when the dew point temperature is low; when the dew point temperature is high, the vent valve 24 is opened to discharge the excess moisture, and the nitrogen gas with a dew point temperature of -40°C is supplemented.

[0032] Of course, the above description is not a limitation on the present application, and the present application is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the spirit and scope of the present application should also be included in the protection scope of the present application.

Claims

1. A nylon 66 chip cooling and aqueous homogenizing system characterized by, The cooling and homogenizing tower, the dust remover, the fan, the cooler, the humidifying metering pump, the water-gas mixer, and the supporting pressure, temperature, dew point, and flow detection instruments and regulating valves are connected through the PLC controller, which automatically adjusts the valves, the frequency of the fan, and the flow of the humidifying metering pump according to the feedback of the detection instruments. The cooling and homogenizing tower is provided with a slice inlet and a nitrogen outlet at the top and a slice outlet at the bottom. The inlet of the fan is connected with the nitrogen outlet through the dust remover, and the outlet of the fan is divided into three paths: the first path is connected with the first-stage cooling pipeline, the outlet of the first-stage cooling pipeline is connected with the nitrogen distributor located at the upper section of the tower, the second path is connected with the second-stage cooling pipeline, the outlet of the second-stage cooling pipeline is connected with the nitrogen distributor located at the middle section of the tower, and the third path is connected with the inlet of the cooler. The connecting pipeline between the nitrogen outlet of the cooling and homogenizing tower and the inlet of the dust remover is provided with a pressure gauge, a thermometer, and a dew point meter, the connecting pipeline between the outlet of the dust remover and the inlet of the fan is provided with a pressure gauge and a nitrogen supplement valve, the first-stage cooling pipeline and the second-stage cooling pipeline are both provided with regulating valves for adjusting the nitrogen inlet amount, the inlet pipeline of the cooler is provided with a vent valve, and the cooling and homogenizing pipeline is provided with a dew point meter, a flow meter, a pressure gauge, and a thermometer.

2. The nylon 66 chip cooling and aqueous homogenizing system of claim 1, wherein, Three thermometers are arranged in the upper section, the middle section, and the lower section of the tower body, and the three thermometers are uniformly distributed at the same height of the tower body.

3. The nylon 66 chip cooling and aqueous homogenizing system of claim 2, wherein, The cooling and homogenizing tower is a stainless steel cylindrical structure, the inner wall of the cooling and homogenizing tower is polished, and the height ratio of the upper section, the middle section, and the lower section of the tower body is 1:1:

2.

4. The nylon 66 chip cooling and aqueous homogenizing system of claim 3, wherein, The nitrogen distributor adopts a horn barrel structure, the dust remover is a bag backflushing dust remover, the fan is a Roots fan, the cooler is a shell-and-tube cooler, the flow meter is a vortex flow meter, and the humidifying metering pump is a diaphragm pump.

5. The nylon 66 chip cooling and aqueous homogenizing system of claim 4, wherein, The tower body of the cooling and homogenizing tower is provided with a continuous material level meter for monitoring the slice material level in the tower.

6. The control process for a nylon 66 chip cooling and aqueous homogenizing system according to any one of claims 1-5, characterized in that, When the high-temperature slice at 80-100℃ enters the cooling and homogenizing tower, the slice flows from top to bottom, and the cold nitrogen enters from the lower part of the cooling and homogenizing tower and flows out from the top, forming a convection with the slice. The nitrogen gas from the top of the cooling homogenizing tower is filtered by a dust catcher and enters a fan. The nitrogen gas at the outlet of the fan is divided into three paths. The first path of the nitrogen gas without cooling is sent to the upper section of the cooling homogenizing tower, mixed with the cold nitrogen gas from below through a nitrogen gas distributor, and the temperature of the upper section is maintained at 60-70℃. The second path of the nitrogen gas without cooling is sent to the middle section of the cooling homogenizing tower, mixed with the cold nitrogen gas from below through a nitrogen gas distributor, and the temperature of the middle section is maintained at 35-45℃. The third path of the nitrogen gas is cooled to 20-30℃ by a cooler, and then the dew point of the third path of the nitrogen gas is controlled at -15℃ through the linkage of a humidifying metering pump and a vent valve on the inlet pipeline of the cooler, and the third path of the nitrogen gas is sent to the nitrogen gas distributor of the lower section of the cooling homogenizing tower and enters the homogenization of the slices.

7. The control process for a nylon 66 chip cooling and aqueous homogenizing system of claim 6, wherein, The pressure of the system is maintained at 10±5kPa, and the apparent flow rate of the nitrogen gas in the cooling homogenizing tower is 0.2m / s.

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