Two-stage continuous crystallization device for chipton

Abstract

The utility model belongs to the technical field of chemical production, concretely relates to a bercyclear two-stage continuous crystallization device, including primary crystallization tower, the lower part of primary crystallization tower is provided with bercyclear inlet pipeline, the upper part of primary crystallization tower is provided with spray head no. One, and spray head no. One is connected with crystal seed conveyor no. One, and the top of primary crystallization tower is connected with secondary crystallization tower through the communicating tube, and the communicating tube is connected with the lower part of secondary crystallization tower, and the upper part of secondary crystallization tower is provided with spray head no. Two, and spray head no. Two is connected with crystal seed conveyor no. Two, and the outside of primary crystallization tower is provided with thermometer no. One, thermometer no. Two and thermometer no. Three, and the outside of secondary crystallization tower is provided with thermometer no. Four, thermometer no. Five and thermometer no. Six, and thermometer no. One, thermometer no. Two, thermometer no. Three, thermometer no. Four, thermometer no. Five and thermometer no. Six are electrically connected with detection controller, and the bottom of primary crystallization tower and secondary crystallization tower is connected with crystallization pipeline. The utility model discloses the efficient operation of continuous production, can promote crystallization efficiency.

Description

Technical Field

[0001] This utility model belongs to the field of chemical production technology, specifically relating to a two-stage continuous crystallization device for chlorothalonil. Background Technology

[0002] The core challenge in chlorothalonil production regarding crystal form control lies in the fact that while highly bioactive type I crystals offer significant advantages, their industrial-scale preparation remains severely hampered. Compared to metastable type II / III crystals, type I crystals exhibit a denser molecular arrangement, with their planar molecular structure fully exposing chlorine atoms, resulting in stronger binding to the target enzyme glyceraldehyde-3-phosphate dehydrogenase and a field efficacy increase of over 70%. They are also resistant to heat and humidity, as well as ultraviolet light, extending their effective period by 5-7 days and significantly reducing application frequency. Furthermore, the crystals are less prone to clumping, with wettable powders exhibiting a suspension rate >75%, meeting the requirements of high-end formulations. However, traditional solid-to-solid crystallization processes struggle to consistently obtain high-purity type I crystals. This process requires incubating the collected metastable crystals at 90–120℃ for crystallization. Due to insufficient temperature control precision, the proportion of type I crystals in the product is generally lower than the agricultural standard (<98%). Residual type II / III crystals not only reduce efficacy but also cause clumping during storage. More importantly, the process lacks real-time control of supersaturation, and the cooling rate relies on experience. An improper cooling rate directly leads to the formation of impurities or excessive crystal growth.

[0003] In recent years, process optimization has attempted to improve efficiency through fluidized bed transformation or gas-solid contact technology, but has failed to overcome fundamental constraints: seed activity decay: pre-made type I seed crystals agglomerate and oxidize during high-temperature transport, reducing surface induction sites and decreasing template effect; the existing "first capture then transformation" segmented mode requires reheating the cooled metastable crystals to the transformation temperature, resulting in a doubling of steam energy consumption; and the lack of online monitoring of key parameters such as lattice stress and supersaturation makes it impossible to correct crystal distortion caused by local overheating in real time. Utility Model Content

[0004] In view of the shortcomings of the prior art, the technical problem to be solved by this utility model is to provide a two-stage continuous crystallization device for chlorothalonil, so as to realize the growth of chlorothalonil on seed crystals, reduce the generation of metastable crystals, obtain chlorothalonil crystals, and improve crystallization efficiency.

[0005] The technical solution adopted by this utility model to solve its technical problem is: The chlorothalonil dual-stage continuous crystallization device of this utility model includes a primary crystallization tower, a chlorothalonil air inlet pipe at the bottom of the primary crystallization tower, a nozzle 1 at the top of the primary crystallization tower connected to a seed crystal conveyor 1, a secondary crystallization tower connected to the top of the primary crystallization tower via a connecting pipe connected to the bottom of the secondary crystallization tower, a nozzle 2 at the top of the secondary crystallization tower connected to a seed crystal conveyor 2, both seed crystal conveyors 1 and 2 connected to a seed crystal tank and a nitrogen tank, thermometers 1, 2, and 3 are installed outside the primary crystallization tower, and thermometers 4, 5, and 6 are installed outside the secondary crystallization tower, all of which are electrically connected to a detection controller, and crystallization pipes are connected to the bottom of both the primary and secondary crystallization towers.

[0006] in: The first-stage crystallization tower is equipped with a Raman probe 1 at the bottom, and the second-stage crystallization tower is equipped with a Raman probe 2 at the bottom. The first Raman probe is located below the chlorothalonil inlet pipe, and the second Raman probe is located below the connecting pipe. The first Raman probe and the second Raman probe have the same structure.

[0007] The Raman probe II includes a receiving plate at the bottom, a needle on the side of the receiving plate, a nitrogen purge tube above the receiving plate, and a guide fork connected to the nitrogen purge tube.

[0008] The first nozzle is positioned opposite to the chlorothalonil air inlet pipe, and the second nozzle is positioned opposite to the second Raman probe. Both the first and second Raman probes are electrically connected to a Raman spectrometer, which is connected to a detection controller.

[0009] A fan is installed at the bottom of the seed tank, and the bottom of the nitrogen tank is electrically connected to the detection controller.

[0010] The seed transporter one and the seed transporter two have the same structure.

[0011] The seed conveyor includes a seed chamber at the top, which is connected to a seed tank. A gas channel is provided at the bottom of the seed conveyor, which is connected to a nitrogen tank. An injection inlet is provided at the connection between the seed chamber and the gas channel. The diameter of the gas channel at the injection inlet is smaller than the diameter at both ends of the gas channel.

[0012] The primary crystallization tower has three heat exchange layers arranged from top to bottom on the outer middle part of the outer side. Each heat exchange layer has a narrow channel in the middle of the primary crystallization tower. Thermometer 1, thermometer 2 and thermometer 3 are respectively arranged inside the three heat exchange layers.

[0013] The secondary crystallization tower has three heat exchange layers arranged from top to bottom on the outer middle part of the outer side. Each heat exchange layer has a narrow channel in the middle of the secondary crystallization tower. Thermometers four, five and six are respectively arranged inside the three heat exchange layers.

[0014] The top of the secondary crystallization tower is connected to a cyclone separator, the top of which is equipped with an exhaust pipe, and the bottom of which is connected to the seed tank.

[0015] The beneficial effects of this utility model are: This invention achieves improved crystal purity by enabling direct epitaxial growth of chlorothalonil on the surface of type I seed crystals through countercurrent contact and graded temperature control, bypassing metastable crystal transformation and increasing crystal purity and stability to over 99.5%. This represents a significant improvement over existing production equipment, solving the problems of product agglomeration and efficacy attenuation. The crystal transformation process is integrated into the collection stage, avoiding repeated heating and cooling of materials. Energy consumption is reduced during use, with pneumatic conveying replacing mechanical conveying and a thermal gradient design that significantly improves energy utilization.

[0016] This invention enables highly efficient continuous production, improving crystallization efficiency. The internal structure of the crystallization tower significantly increases crystal residence time, with a gas residence time of at least 9 minutes in the primary crystallization tower and at least 13 minutes in the secondary crystallization tower. Combined with the crystal growth process and continuous discharge from the crystallization pipe at the bottom of the tower, the entire process is continuously operated. Production capacity is increased compared to traditional intermittent processes. It prevents lattice defects caused by equipment start-ups and shutdowns. Continuous discharge ensures efficient and stable system operation, avoiding long-term equipment maintenance. The seed crystal conveyor features a wear-resistant silicon carbide lining and a tapered-expanding structure that creates a negative pressure ejection effect. The flow velocity at the injection inlet is 8-12 m / s, instantly mixing preheated nitrogen with the seed crystal into a uniform gas-solid flow, preventing bridging and blockage caused by mechanical conveying. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 yes Figure 1 Enlarged view of the structure at point A in the middle; Figure 3 This is a schematic diagram of the structure of the seed crystal conveyor of this utility model; In the diagram: 1. Chlorothalonil air inlet pipe; 2. Thermometer 1; 3. Raman probe 1; 4. Nozzle 1; 5. Thermometer 2; 6. Seed delivery device 1; 7. Thermometer 3; 8. Primary crystallization tower; 9. Detection controller; 10. Seed delivery device 2; 11. Connecting pipe; 12. Raman probe 2; 13. Crystallization pipe; 14. Thermometer 4; 15. Thermometer 5; 16. Nozzle 2; 17. Thermometer 6; 18. Secondary crystallization tower; 19. Exhaust pipe; 20. Cyclone separator; 21. Nitrogen tank; 22. Seed tank; 601. Seed chamber; 602. Injection inlet; 603. Gas channel; 901. Raman spectrometer; 1201. Nitrogen purge pipe; 1202. Receiver plate; 1203. Needle; 1204. Guide fork; 2201. Fan. Detailed Implementation

[0018] The embodiments of this utility model will be further described below with reference to the accompanying drawings.

[0019] Example 1 like Figure 1-3 As shown, the chlorothalonil dual-stage continuous crystallization device of this utility model includes a primary crystallization tower 8, a chlorothalonil air inlet pipe 1 at the bottom of the primary crystallization tower 8, a nozzle 4 at the top of the primary crystallization tower 8, a seed crystal conveyor 6 connected to the nozzle 4, a secondary crystallization tower 18 connected to the top of the primary crystallization tower 8 via a connecting pipe 11, the connecting pipe 11 being connected to the lower part of the secondary crystallization tower 18, a nozzle 16 at the top of the secondary crystallization tower 18, and a seed crystal conveyor 10 connected to the nozzle 16 for seed crystal delivery. Both the first crystallizer 6 and the second crystallizer 10 are connected to the seed tank 22 and the nitrogen tank 21. Thermometer 12, thermometer 25 and thermometer 37 are installed on the outside of the first-stage crystallizer 8. Thermometer 414, thermometer 515 and thermometer 617 are installed on the outside of the second-stage crystallizer 18. Thermometer 12, thermometer 25, thermometer 37, thermometer 414, thermometer 515 and thermometer 617 are electrically connected to the detection controller 9. Crystallization pipes 13 are connected to the bottom of both the first-stage crystallizer 8 and the second-stage crystallizer 18.

[0020] Raman probe 13 is installed at the bottom of the primary crystallization tower 8, and Raman probe 212 is installed at the bottom of the secondary crystallization tower 18. Raman probe 13 is located below the chlorothalonil inlet pipe 1, and Raman probe 212 is located below the connecting pipe 11. Raman probe 13 and Raman probe 212 have the same structure.

[0021] Raman probe 2 12 includes a receiving plate 1202 at the bottom, a needle 1203 on the side of the receiving plate 1202, a nitrogen purge tube 1201 above the receiving plate 1202, and a guide fork 1204 connected to the nitrogen purge tube 1201.

[0022] Spray nozzle 14 is positioned opposite to the chlorothalonil air inlet pipe 1, and spray nozzle 216 is positioned opposite to Raman probe 212. Both Raman probe 13 and Raman probe 212 are electrically connected to Raman spectrometer 901, which is connected to detection controller 9.

[0023] A blower 2201 is installed at the bottom of the seed tank 22, and the bottom of the nitrogen tank 21 is electrically connected to the detection controller 9.

[0024] Seed transporter 16 and seed transporter 210 have the same structure.

[0025] The seed conveyor 6 includes a seed chamber 601 at the top, which is connected to the seed tank 22. A gas channel 603 is provided at the bottom of the seed conveyor 6, which is connected to the nitrogen tank 21. An injection inlet 602 is provided at the connection between the seed chamber 601 and the gas channel 603. The diameter of the gas channel 603 at the injection inlet 602 is smaller than the diameters at both ends of the gas channel 603.

[0026] Three heat exchange layers are arranged from top to bottom on the outer middle of the primary crystallization tower 8. Each heat exchange layer has a narrow channel in the middle of the primary crystallization tower 8. Thermometer 12, thermometer 25 and thermometer 37 are respectively arranged inside the three heat exchange layers.

[0027] The secondary crystallizer 18 has three heat exchange layers arranged from top to bottom on the outer middle part of the outer side. Each heat exchange layer has a narrow channel in the middle of the secondary crystallizer 18. Thermometer 4 14, thermometer 5 15 and thermometer 6 17 are respectively arranged inside the three heat exchange layers.

[0028] The top of the secondary crystallization tower 18 is connected to a cyclone separator 20, the top of which is equipped with an exhaust pipe 19, and the bottom of the cyclone separator 20 is connected to the seed tank 22.

[0029] Working principle and process: First, type I chlorothalonil seeds with an average particle size of 40μm in seed tank 22 are quantitatively transported by blower 2201 to seed chamber 601 in seed conveyor 6 to avoid agglomeration and oxidation. At the same time, nitrogen in nitrogen tank 21 is transported to gas channel 603, and then nitrogen and seeds are made to meet at injection inlet 602 to make nitrogen and seeds uniformly mixed for easy seed carrying. Then, the gas-solid mixture is transported to the upper part of primary crystallization tower 8 and sprayed to the lower part of primary crystallization tower 8 through nozzle 4. Chlorothalonil gas is transported to the lower part of primary crystallization tower 8 through chlorothalonil inlet pipe 1 at a ratio of seed to raw material gas of 1:10-15. The upward flow of gas achieves counter-current mixing of seed and chlorothalonil gas, so that chlorothalonil gas grows directionally on the seed surface. The seed crystals undergo a process of rising and growing under the influence of gravity, gas thrust, and resistance, followed by a descent under gravity once they reach a certain size, thus increasing the crystal's residence time. The top temperature of the primary crystallization tower 8 is maintained above 360℃ to prevent chlorothalonil from crystallizing on the inner wall surface and pipes of the tower. The middle section of the primary crystallization tower 8 is the growth zone, where optimal crystallization temperature is maintained through heat transfer oil in three heat exchange layers. Temperature is monitored in real-time by thermometers 7, 5, and 2 (located from top to bottom) in the growth zone, and the data is fed back to the detection controller 9. The monitored temperatures are 245-265℃, 250-300℃, and 320-280℃ respectively. If the temperature in any of the three sections of the growth zone is too high, the heat transfer oil circulation rate is increased to lower the temperature; if the temperature is too low, the heat transfer oil flow rate is reduced, utilizing the heat from the raw material gas to raise the temperature. The bottom of the primary crystallization tower 8 is insulated to prevent caking and ensure settling. Simultaneously, the Raman probe 3 scans the crystals every 2 minutes, and the relevant data is analyzed by the Raman spectrometer 901 to check if the peak values ​​are within the product specifications. If the product data does not meet the requirements, the crystallization conditions inside the primary crystallization tower 8 are adjusted, stabilized for 8 minutes, and then scanned again until the obtained product meets the specifications. The crystals precipitated from the primary crystallization tower 8, under the influence of gravity, pass through the middle section of the tower. The narrow diameter of the middle section slows down the crystal's descent, increasing the crystal growth time. Qualified crystals settle at a reduced speed and are continuously discharged from the bottom of the primary crystallization tower 8 into the crystallization pipe 13, resulting in finished crystals with an average diameter of approximately 0.5 mm. The remaining gas is transported to the lower part of the secondary crystallization tower 18 via the connecting pipe 11.

[0030] The seeds in seed tank 22 and the nitrogen in nitrogen tank 21 are transported to seed conveyor 10. The mixing process of the seeds and nitrogen is the same as that of seed conveyor 6. Then, the mixture is transported to the upper part of the secondary crystallization tower 18. At this time, the amount of seeds added is 35% of that added to the primary crystallization tower 8. The gas-solid mixture is sprayed downward from the upper part of nozzle 16 in the secondary crystallization tower 18. The remaining gas comes into countercurrent contact with the gas-solid mixture, and the chlorothalonil gas grows directionally on the surface of the seeds. The crystallization process is the same as that of the primary crystallization tower 8. Thermometers 17, 15, and 14, which are set from top to bottom in the growth zone of the secondary crystallization tower 18, monitor the temperature of each section in real time. The data is fed back to the detection controller 9. The monitored temperatures are 110-160℃, 200-180℃, and 240-200℃, respectively. The crystallization and sedimentation process is the same as that of the primary crystallization tower 8.

[0031] Raman probe 12 scans the crystals on receiving plate 1202 every 4 minutes, and nitrogen purging tube 1201 is started simultaneously to clean the fine dust on the window surface to ensure accurate detection. Mature crystals fall and accumulate on crystal receiving plate 1202. The probe 1203 scans and detects the crystals. During the detection interval, the atmospheric velocity is increased to blow away the crystal seeds on receiving plate 1202. New crystal seeds are then received for the next scan. Every 4 minutes, the crystals on the receiving plate are cleared to reset the sample. The relevant data detected by Raman probe 12 are analyzed by Raman spectrometer 901. The detection principle is the same as that of the first-stage crystallization tower 8.

[0032] Unsettled fine powder and gas enter the cyclone separator 20 directly from the top of the secondary crystallization tower 18. The purified gas is recovered and processed through the exhaust pipe 19. The separated dust is collected, screened, and transported back to the seed tank 22 as regenerated seed crystals for reuse, forming a closed loop.

Claims

1. A two-stage continuous crystallization device for chlorothalonil, comprising a primary crystallization tower (8), characterized in that, The lower part of the primary crystallization tower (8) is equipped with a chlorothalonil air inlet pipe (1), and the upper part of the primary crystallization tower (8) is equipped with a nozzle (4). The nozzle (4) is connected to a seed crystal conveyor (6). The top of the primary crystallization tower (8) is connected to a secondary crystallization tower (18) through a connecting pipe (11). The connecting pipe (11) is connected to the lower part of the secondary crystallization tower (18). The upper part of the secondary crystallization tower (18) is equipped with a nozzle (16). The nozzle (16) is connected to a seed crystal conveyor (10). Both the seed crystal conveyor (6) and the seed crystal conveyor (10) are connected to seed crystal tanks. (22) and nitrogen tank (21), thermometer 1 (2), thermometer 2 (5) and thermometer 3 (7) are installed on the outside of the primary crystallizer (8), thermometer 4 (14), thermometer 5 (15) and thermometer 6 (17) are installed on the outside of the secondary crystallizer (18), thermometer 1 (2), thermometer 2 (5), thermometer 3 (7), thermometer 4 (14), thermometer 5 (15) and thermometer 6 (17) are electrically connected to a detection controller (9), and crystallization pipes (13) are connected to the bottom of the primary crystallizer (8) and the secondary crystallizer (18).

2. The chlorothalonil dual-stage continuous crystallization apparatus according to claim 1, characterized in that, Raman probe 1 (3) is installed at the bottom of the primary crystallization tower (8), and Raman probe 2 (12) is installed at the bottom of the secondary crystallization tower (18). Raman probe 1 (3) is located below the chlorothalonil air inlet pipe (1), and Raman probe 2 (12) is located below the connecting pipe (11). Raman probe 1 (3) and Raman probe 2 (12) have the same structure.

3. The chlorothalonil dual-stage continuous crystallization apparatus according to claim 2, characterized in that, Raman probe 2 (12) includes a receiving plate (1202) at the bottom, a needle (1203) on the side of the receiving plate (1202), a nitrogen purge tube (1201) above the receiving plate (1202), and a guide fork (1204) connected to the nitrogen purge tube (1201).

4. The chlorothalonil dual-stage continuous crystallization apparatus according to claim 1, characterized in that, The nozzle 1 (4) is set opposite to the chlorothalonil air inlet pipe (1), the nozzle 2 (16) is set opposite to the Raman probe 2 (12), and both the Raman probe 1 (3) and the Raman probe 2 (12) are electrically connected to the Raman spectrometer (901). The Raman spectrometer (901) is connected to the detection controller (9).

5. The chlorothalonil dual-stage continuous crystallization apparatus according to claim 1, characterized in that, A blower (2201) is installed at the bottom of the seed tank (22), and the bottom of the nitrogen tank (21) is electrically connected to the detection controller (9).

6. The chlorothalonil dual-stage continuous crystallization apparatus according to claim 1, characterized in that, Seed transporter one (6) has the same structure as seed transporter two (10).

7. The chlorothalonil dual-stage continuous crystallization apparatus according to claim 6, characterized in that, The seed delivery device (6) includes a seed chamber (601) at the top, which is connected to the seed tank (22). A gas channel (603) is provided at the bottom of the seed delivery device (6), which is connected to the nitrogen tank (21). An injection inlet (602) is provided at the connection between the seed chamber (601) and the gas channel (603). The diameter of the gas channel (603) at the injection inlet (602) is smaller than the diameter at both ends of the gas channel (603).

8. The chlorothalonil dual-stage continuous crystallization apparatus according to claim 1, characterized in that, Three heat exchange layers are arranged from top to bottom on the outer middle of the primary crystallization tower (8). A narrow channel is provided in the middle of the primary crystallization tower (8) in each heat exchange layer. Thermometer 1 (2), thermometer 2 (5) and thermometer 3 (7) are respectively arranged inside the three heat exchange layers.

9. The chlorothalonil dual-stage continuous crystallization apparatus according to claim 1, characterized in that, The secondary crystallizer (18) has three heat exchange layers from top to bottom in the middle of the outer side. Each heat exchange layer has a narrow channel in the middle of the secondary crystallizer (18). Thermometer 4 (14), thermometer 5 (15) and thermometer 6 (17) are respectively installed inside the three heat exchange layers.

10. The chlorothalonil dual-stage continuous crystallization apparatus according to claim 1, characterized in that, The top of the secondary crystallization tower (18) is connected to a cyclone separator (20), the top of the cyclone separator (20) is provided with an exhaust pipe (19), and the bottom of the cyclone separator (20) is connected to the seed tank (22).

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