A clean production crystallization device and method for preparing salicylonitrile by using phosgene

Abstract

This invention relates to the field of crystallization equipment, and discloses a crystallization device and method for the clean production of salicylates from phosgene. It solves the problems of low stirring efficiency in existing crystallization equipment, the inability to adjust the mixing rate according to the crystallization status of the solution inside the vessel during stirring, increased mixing difficulty, and blockage of the feed pipe during material feeding. The device includes an upper vessel and a lower vessel connected to each other. The upper vessel has a power component at its upper end, a cooling component on the outside of the lower vessel, a support component on the outside of the cooling component, a feeding component at the bottom of the lower vessel, and a mixing component inside the lower vessel. The mixing component has an impact component at its bottom. This invention uses a displacement sensor in conjunction with a vertical plate to identify the crystallization effect of the solution inside the lower vessel at a specific shaft rotation speed, and then adjusts the shaft rotation speed accordingly to ensure stable stirring efficiency.

Description

Technical Field

[0001] This invention belongs to the field of crystallization equipment, specifically a crystallization equipment and method for the clean production of salicylnitrile from phosgene. Background Technology

[0002] Salicylic nitrile, also known as o-hydroxybenzonitrile, is a grayish-white powdery solid with a highly irritating odor. Even a small amount can affect respiration. It has a bitter smell and is commonly used as an intermediate in the organic synthesis of bunirol and as an intermediate in the fungicide pyraclostrobin. Currently, the main methods for synthesizing salicylic nitrile are the phosgene method and the non-phosgene method. The phosgene method uses salicylamide as a raw material, which is purified by photochemical reaction and acid-base purification to obtain salicylic nitrile. Drying and crystallization are required during purification.

[0003] For example, Chinese patent application number CN202123211206.3 discloses a salicylate crystallization device, including a tank and a heater. The top of the tank is not closed, and an mounting plate is fitted on the side wall of the tank. The tank and the mounting plate are slidably connected. A first toothed rack is fixedly connected to the side wall of the tank. Through the cooperation between the tank, the mounting plate, the motor, the horizontal plate, the horizontal rod, and the vertical rod, the motor can drive the tank to rotate forward and the stirring rod to rotate in reverse, so that the tank and the stirring rod rotate in opposite directions. This can effectively solve the problem that the stirrer only stirs in one direction and the stirring effect of the solution is not good. However, changing the stirring direction still results in uneven stirring and low stirring efficiency.

[0004] Existing crystallization equipment cannot adjust the mixing rate according to the crystallization status of the solution in the vessel during the stirring process. During the crystallization process, crystals will adhere to the inner wall of the vessel, resulting in crystal residue inside the vessel. As crystals gradually precipitate during stirring, the number of crystals inside the solution increases, the viscosity increases, and the mixing becomes more difficult. Furthermore, the feeding pipe may be blocked during the feeding process, affecting the crystallization efficiency of salicylnitrile. Summary of the Invention

[0005] To address the above issues and overcome the shortcomings of existing technologies, this invention provides a crystallization device and method for the clean production of salicylanilic acid from phosgene. This effectively solves the problems of uneven stirring and low stirring efficiency in existing crystallization equipment. Furthermore, during stirring, the mixing rate cannot be adjusted according to the crystallization status of the solution inside the vessel. Crystals adhere to the inner wall of the vessel during crystallization, resulting in residual crystals inside. As crystals gradually precipitate during stirring, the number of crystals inside the solution increases, leading to higher viscosity and greater difficulty in mixing. Additionally, the feeding pipe may become clogged during the feeding process, affecting the crystallization efficiency of salicylanilic acid.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a crystallization device for the clean production of salicylates from phosgene, comprising an upper vessel and a lower vessel, wherein the upper vessel and the lower vessel are connected to each other, a power assembly is provided at the upper end of the upper vessel, a cooling assembly is provided on the outer side of the lower vessel, a support assembly is provided on the outer side of the cooling assembly, a feeding assembly is provided at the bottom of the lower vessel, a mixing assembly is provided inside the lower vessel, and an impact assembly is provided at the bottom of the mixing assembly;

[0007] The mixing assembly includes a shaft, with two sleeves located in the middle of the shaft. The two sleeves are symmetrically arranged about the center of the shaft. A telescopic rod is slidably connected inside the sleeves, and a vertical plate is hinged to the outside of the telescopic rod. A first connecting rod is located at the top of the outer side of the sleeve, and a second connecting rod is located outside the first connecting rod. The second connecting rod is fixedly connected to the vertical plate. A slider is slidably connected inside the shaft, and two inclined rods are located outside the slider. The two inclined rods are symmetrically arranged about the center of the shaft, and the inclined rods are connected to the outer ends of the telescopic rod.

[0008] The impact assembly includes a cylindrical body, a cylindrical rod at the bottom of the slider, the cylindrical rod being slidably connected to the shaft, a cavity at the bottom of the shaft, an electromagnet at the top of the cavity, the cylindrical rod passing through the electromagnet, a fixed magnet at the bottom of the cylindrical rod, the fixed magnet being slidably connected to the shaft, a displacement sensor at one side of the fixed magnet, a support plate at the lower end of the fixed magnet, the bottom of the support plate being connected to the cylindrical body, and a conical head at the bottom of the cylindrical body.

[0009] Preferably, a spring is sleeved on the outer side of the top of the cylindrical rod, the top of the spring is connected to the bottom of the slider, and the bottom of the spring is connected to the shaft.

[0010] Preferably, the outer side of the fixed magnet has several round holes evenly arranged, and the outer side of the cylinder is provided with two paddle plates, which are arranged symmetrically.

[0011] Preferably, the power assembly includes a motor, a reducer is provided at the bottom of the motor, a transmission rod is provided at the bottom of the reducer, the top of the transmission rod passes through the upper vessel body, and the bottom of the transmission rod is connected to the top of the shaft body.

[0012] Preferably, the cooling assembly includes a jacket, which is connected to the outside of the lower vessel body. Cooling pipes are provided inside the jacket and the lower vessel body, and the cooling pipes are spirally arranged inside the jacket.

[0013] Preferably, the bottom of the cooling pipe is connected to a water inlet pipe, and the top of the cooling pipe is connected to a water outlet pipe, with the water inlet pipe and the water outlet pipe penetrating the side wall of the lower vessel.

[0014] Preferably, the support assembly includes several frames, which are evenly arranged on the outside of the sleeve. The frames are provided with legs inside, and the bottom of the legs is provided with a base plate.

[0015] Preferably, a feed pipe is provided on one side of the top of the upper vessel, and a cover plate is provided at the top of the feed pipe. A liquid replenishment pipe is provided on the other side of the upper vessel, and a screw cap is provided at the top of the liquid replenishment pipe.

[0016] Preferably, the feeding assembly includes a feeding pipe, the top of which is connected to the bottom of the lower vessel body, the feeding pipe passes through the bottom of the jacket, and a discharge pipe is provided at the bottom of the feeding pipe.

[0017] A method for preparing salicylaniline from phosgene by crystallization includes the following steps:

[0018] S1: Add solution to the upper and lower vessel bodies, and drive the shaft to rotate via the power assembly;

[0019] S2: The shaft drives the vertical plate and the paddle plate to rotate. While the shaft rotates, the angle of the vertical plate deflects. The height of the paddle plate changes while the shaft rotates. The impact component intermittently impacts the bottom of the lower vessel to prevent blockage while the shaft rotates.

[0020] S3: The displacement sensor identifies the deflection angle of the vertical plate during rotation, detects the degree of reaction of the solution inside the lower vessel, and adjusts the rotation speed of the power component and the operating frequency of the impact component accordingly.

[0021] S4: The crystallized solution is discharged from the lower reactor body through the feed pipe, and the solution is transported through the discharge pipe.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] (1) By adjusting the rotation speed of the shaft, the vertical plate can move in a circle. While moving in a circle, its own deflection angle changes with the rotation speed, thereby changing the flow direction of the solution inside the lower vessel and achieving uniform stirring of the solution inside the lower vessel from the inside to the outside. At the same time, it drives the lower slurry plate to rotate. Combined with the intermittent spraying of the cylinder, the solution at the bottom of the lower vessel is mixed evenly.

[0024] (2) By limiting the rotation speed of the shaft and using a displacement sensor to identify the tilt state of the vertical plate, the crystallization status inside the solution can be reflected. Then, the rotation speed of the shaft is adjusted accordingly to ensure the mixing efficiency of the solution. When the gradual precipitation of crystals inside the solution is detected and the viscosity of the solution increases, the rotation speed of the shaft is reduced. By controlling the magnetic pole of the fixed magnet, the movement amplitude and angle change frequency of the vertical plate are changed. This not only reduces the load on the power components, but also does not reduce the mixing rate of the solution inside the lower vessel. Furthermore, by controlling the magnetic pole of the electromagnet to switch quickly, the fixed magnet is driven to move quickly, realizing the rapid reciprocating movement of the cylinder. The space between the cylinder and the lower end of the shaft changes drastically, and a rapid liquid pumping and spraying action is performed to prevent the problem of blockage at the discharge port as the viscosity of the solution increases.

[0025] (3) By using a displacement sensor in conjunction with an electromagnet, the movement of the vertical plate and the slurry plate is controlled so that when the vertical plate contacts the inner wall of the lower reactor, there is a certain angle between them. This not only enhances the efficiency of scraping off residues, but also effectively reduces wear on the vertical plate, increases the service life of the vertical plate, and prevents more crystal residues from appearing on the inner wall of the reactor during the crystallization process, which would lead to a decrease in the crystallization efficiency inside the reactor. Attached Figure Description

[0026] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0027] In the attached diagram:

[0028] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0029] Figure 2 This is a schematic diagram of the cross-sectional structure of the jacket of the present invention.

[0030] Figure 3 This is a schematic diagram of the cross-sectional structure of the upper and lower vessel bodies of the present invention.

[0031] Figure 4 This is a schematic diagram of the cooperation between the vertical plate and the paddle plate of the present invention.

[0032] Figure 5 This is a schematic diagram of the cooperation structure between the slider and the vertical plate of the present invention.

[0033] Figure 6 This is a schematic diagram of the state after the vertical plate angle of the present invention has been adjusted.

[0034] Figure 7 This is a schematic diagram of the structure of the telescopic rod and the vertical plate of the present invention.

[0035] Figure 8For the present invention Figure 5 A magnified view of part A in the middle.

[0036] Figure 9 For the present invention Figure 6 Enlarged view of part B in the middle.

[0037] Figure 10 This is a schematic diagram of the fit between the cylindrical rod and the cylinder body of the present invention.

[0038] Labels in the diagram: 1. Power assembly; 2. Cover plate; 3. Feed pipe; 4. Liquid replenishment pipe; 5. Screw cap; 6. Upper vessel body; 7. Jacket; 8. Frame; 9. Support leg; 10. Base plate; 11. Water inlet pipe; 12. Lower vessel body; 13. Cooling pipe; 14. Water outlet pipe; 15. Feed pipe; 16. Discharge pipe; 17. Transmission rod; 18. Shaft; 19. Slider; 20. Diagonal rod; 21. Spring; 22. Cylindrical rod; 23. Sleeve; 24. Telescopic rod; 25. First connecting rod; 26. Second connecting rod; 27. Vertical plate; 28. Cylinder; 29. ​​Conical head; 30. Slurry plate; 31. Electromagnet; 32. Fixed magnet; 33. Support plate; 34. Circular hole. Detailed Implementation

[0039] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0040] Example 1:

[0041] Depend on Figures 1-10 To address the issue of uneven solution mixing and low crystallization efficiency in existing crystallization equipment, this invention proposes a clean crystallization device for the production of salicylates from phosgene. The device comprises an upper vessel 6 and a lower vessel 12, which are interconnected. A power assembly 1 is located at the upper end of the upper vessel 6. A cooling assembly is located on the outer side of the lower vessel 12, and a support assembly is located on the outer side of the cooling assembly. A feeding assembly is located at the bottom of the lower vessel 12, and a mixing assembly is located inside the lower vessel 12. An impact assembly is located at the bottom of the mixing assembly. The cooling assembly and mixing assembly enable better uniform mixing of the solutions inside the upper vessel 6 and the lower vessel 12. Furthermore, the impact assembly accelerates the mixing of the solution at the bottom of the lower vessel 12, ensuring improved overall mixing efficiency.

[0042] To improve the mixing efficiency of the solution inside the vessel, specifically, the power assembly 1 includes a motor, a reducer at the bottom of the motor, a transmission rod 17 at the bottom of the reducer, the top of the transmission rod 17 penetrating the vessel body 6, and the bottom of the transmission rod 17 being connected to the top of the shaft 18. The mixing assembly includes the shaft 18, with two sleeves 23 in the middle of the shaft 18. The two sleeves 23 are symmetrically arranged about the center of the shaft 18. A telescopic rod 24 is slidably connected inside the sleeve 23, and a vertical plate 27 is hinged to the outside of the telescopic rod 24. A first connecting rod 25 is provided on the top outer side of the 3, and a second connecting rod 26 is provided on the outer side of the first connecting rod 25. The second connecting rod 26 is fixedly connected to the vertical plate 27. A slider 19 is slidably connected inside the shaft 18. Two inclined rods 20 are provided on the outer side of the slider 19. The two inclined rods 20 are symmetrically arranged with the center of the shaft 18 as the axis of symmetry. The inclined rods 20 are connected to the outer ends of the telescopic rod 24. A spring 21 is sleeved on the outer side of the top of the cylindrical rod 22. The top of the spring 21 is connected to the bottom of the slider 19, and the bottom of the spring 21 is connected to the shaft 18.

[0043] The motor and reducer in power assembly 1 are existing technologies and are not shown in the figure. The rotation of the motor, combined with the reducer, ensures the smooth rotation of the transmission rod 17, which drives the fixedly connected shaft 18 to rotate. When the shaft 18 rotates, it drives the sleeves 23 on both sides and the telescopic rod 24 to rotate synchronously, realizing the circumferential movement of the vertical plate 27. Under the action of centrifugal force, the telescopic rod 24 will extend outward. During the extension process, the circumferential movement radius of the vertical plate 27 will increase. As the rotation speed of the shaft 18 gradually increases, the rotation area of ​​the vertical plate 27 will increase accordingly, realizing the uniform rotation of the solution inside the lower vessel 12 from the inside to the outside. When the rotation speed of the shaft 18 increases, the vertical plate 27 is subjected to centrifugal force... As the centrifugal force gradually increases, it will drive the telescopic rod 24 to move outward. Since the first connecting rod 25 and the sleeve 23 are hinged to each other and the hinge point position remains unchanged, when the vertical plate 27 moves outward, the first connecting rod 25 will pull the hinged second connecting rod 26 to rotate. The second connecting rod 26 will drive the fixedly connected vertical plate 27 to rotate, so that the angle of the vertical plate 27 gradually changes during the outward movement, thereby changing the direction of the solution movement inside the lower float, so that solutions with different flow directions are generated inside the lower vessel 12, and the efficiency of internal solution mixing is accelerated. The tilt angle of the vertical plate 27 can be controlled by controlling the rotation speed of the shaft 18. The shaft 18 can gradually change from low speed to high speed to complete the uniform stirring inside the entire lower vessel 12.

[0044] When the telescopic rod 24 reciprocates under the action of centrifugal force, it will cause the bottom of the hinged diagonal rod 20 to shift outward, thereby pulling the diagonal rod 20 downward, causing the hinged slider 19 to descend vertically inside the shaft 18, and causing the fixedly connected cylindrical rod 22 to move inside the shaft 18. At the same time, as the slider 19 moves downward, the spring 21 is compressed. When the rotation speed of the shaft 18 decreases, the slider 19 is pushed back to its original position under the reaction force of the spring 21, so that the telescopic rod 24 is reset synchronously, and the angle of the vertical plate 27 returns to its initial state.

[0045] Existing crystallization equipment cannot accelerate the mixing of the solution at the bottom of the vessel during stirring, which easily leads to precipitation at the bottom of the vessel and uneven mixing. The impact component includes a cylinder 28, a cylindrical rod 22 at the bottom of the slider 19, the cylindrical rod 22 being slidably connected to the shaft 18, a fixed magnet 32 ​​at the bottom of the cylindrical rod 22 being slidably connected to the shaft 18, a support plate 33 at the lower end of the fixed magnet 32, the bottom of the support plate 33 being connected to the cylinder 28, a conical head 29 at the bottom of the cylinder 28, and several round holes 34 evenly arranged on the outer side of the fixed magnet 32 ​​to ensure the internal air communication. Two slurry plates 30 are symmetrically arranged on the outer side of the cylinder 28. Through the liquid extraction and spraying inside the cylinder 28, in conjunction with the conical head 29, the solution at the bottom of the lower vessel 12 can be impacted, accelerating the upward flow of the lower solution and promoting the mixing of the lower solution.

[0046] As the shaft 18 rotates, it drives the cylindrical rod 22 to rise and fall inside the shaft 18. The faster the shaft 18 rotates, the greater the descent of the cylindrical rod 22. As the shaft 18 rotates from low to high, the cylindrical rod 22 drives the fixed magnet 32 ​​and the support plate 33 to descend. At this time, the space between the cylinder 28 and the lower end of the shaft 18 gradually increases, and a negative pressure begins to form inside. As the cylinder 28 moves downward, the solution inside the lower vessel 12 is drawn into the cylinder 28. A filter screen is provided at the bottom of the conical head 29 to prevent the precipitated crystals from being sucked into the cylinder 28. Inside the cylinder 28, as the rotational speed of the shaft 18 decreases, the cylindrical rod 22 is pushed upward by the spring 21, thereby compressing the space between the cylinder 28 and the lower part of the shaft 18. The pressure inside the cylinder 28 gradually increases, and the solution inside the cylinder 28 is ejected through the conical head 29 under pressure. This can effectively increase the flow rate at the bottom of the solution and promote the upward flow of the solution at the bottom. Furthermore, as the cylinder 28 rotates, it will drive the fixedly connected slurry plates 30 on both sides to rotate. The slurry plates 30 can also be raised and lowered with the cylinder 28, thus achieving thorough mixing of the solution at the bottom of the lower vessel 12.

[0047] To accelerate crystal precipitation, the solution temperature can be reduced to increase the precipitation rate. The cooling assembly includes a jacket 7, which is connected to the outside of the lower vessel 12. Cooling pipes 13 are installed inside the jacket 7 and the lower vessel 12. The cooling pipes 13 are spirally arranged inside the jacket 7. A water inlet pipe 11 is connected to the bottom of the cooling pipe 13, and a water outlet pipe 14 is connected to the top of the cooling pipe 13. The water inlet pipe 11 and the water outlet pipe 14 penetrate the side wall of the lower vessel 12. Cooler water enters the spiral cooling pipe 13 through the water inlet pipe 11, absorbs heat from the top of the cooling pipe 13, and flows out. This ensures that the temperature inside the jacket 7 is reduced, thereby reducing the temperature inside the lower vessel 12.

[0048] The support assembly includes several frames 8, which are evenly arranged on the outside of the sleeve 7. The inside of the frame 8 is provided with support legs 9, and the bottom of the support legs 9 is provided with a base plate 10. The frame 8 is fixed to the outside of the sleeve 7, which can fix the top of the support legs 9 inside the frame 8. At the same time, the base plate 10 can increase the contact area between the device and the ground to prevent the device from tipping over.

[0049] A feed pipe 3 is provided on one side of the top of the upper vessel 6, and a cover plate 2 is provided at the top of the feed pipe 3. A replenishment pipe 4 is provided on the other side of the upper vessel 6, and a screw cap 5 is provided at the top of the replenishment pipe 4. By opening the cover plate 2, the solution inside the upper vessel 6 and the lower vessel 12 can be increased through the feed pipe 3. By opening the screw cap 5, additives and other substances can be added to the solution.

[0050] The feeding assembly includes a feeding pipe 15, the top of which is connected to the bottom of the lower vessel 12. The feeding pipe 15 passes through the bottom of the jacket 7, and a discharge pipe 16 is provided at the bottom of the feeding pipe 15. The crystallized slurry is discharged from the inside of the lower vessel 12 through the feeding pipe 15 and then filtered and dried through the discharge pipe 16.

[0051] Example 2:

[0052] Based on Embodiment 1, this embodiment takes into account that the mixing rate cannot be adjusted according to the crystallization of the solution in the lower vessel 12 during the stirring process. As the stirring and crystallization continue, the mixing difficulty gradually increases, and crystal residue will appear on the inner wall of the vessel. Furthermore, the discharge port may be blocked when discharging material at the end of the crystallization period. By providing a cavity at the bottom of the shaft 18, and an electromagnet 31 at the top of the cavity, a cylindrical rod 22 passes through the electromagnet 31, and a displacement sensor is provided on one side of the fixed magnet 32. The displacement sensor can identify the movement of the cylindrical rod 22. The electromagnet 31 at the top of the cavity can control the movement distance of the fixed magnet 32, and the movement of the fixed magnet 32 ​​can be controlled in some special cases.

[0053] During the stirring process, as the overall temperature of the solution decreases, crystals gradually precipitate. The increasing number of crystals leads to an increase in viscosity. When the viscosity reaches a certain value, it signifies the completion of crystal precipitation. Before stirring begins, a certain rotational speed of the shaft 18 is set as the detection speed—the initial speed at which stirring begins and before crystal precipitation. This means that the shaft 18 can identify the state of the solution inside the lower vessel 12 at this speed. First, the solution is added to the lower vessel 12 without cooling. The shaft 18 rotates at the detection speed. Under centrifugal force, the vertical plates 27 on both sides move outwards simultaneously, exhibiting a certain angular deflection. This deflection angle is the same as the rotation direction of the shaft 18, i.e., the shaft 18 rotates counterclockwise, and the vertical plates 27 also swing counterclockwise. Figure 5 Become Figure 6 As shown, at this rotational speed, the deflection angle of the vertical plate 27 when no crystals precipitate in the solution can be determined. The height of the cylindrical rod 22 is identified by the displacement sensor, and the state of the vertical plate 27 is reflected.

[0054] Then, the jacket 7 is controlled to cool down the solution inside the lower vessel 12. This, combined with the rotation of the shaft 18, initiates crystallization. As crystals gradually precipitate from the solution, the viscosity increases due to the crystals. This crystallization exerts a greater reaction force on the moving vertical plate 27. With the increased viscosity of the solution, without increasing the rotational speed of the shaft 18, the vertical plate 27 begins to rotate in the opposite direction. Since the position of the sleeve 23 is fixed, the vertical plate 27 drives the fixedly connected second connecting rod 26 to rotate clockwise. The movement, under the pulling force of the first connecting rod 25, drives the telescopic rod 24 to retract into the sleeve 23. The telescopic rod 24 drives the corresponding inclined rod 20 to shift upward, so that the slider 19 drives the fixedly connected cylindrical rod 22 to rise. The displacement sensor can monitor the rise of the cylindrical rod 22. The higher the rise, the higher the viscosity of the solution inside the lower vessel 12, and the higher the efficiency of crystal precipitation. The rotation speed of the control shaft 18 is stabilized in the detection state. With the help of the displacement sensor, the precipitation of crystals inside the solution can be identified.

[0055] During the stirring of the solution, the rotation speed of the shaft 18 needs to be intermittently adjusted to the detection speed. A displacement sensor is used to identify the deflection angle of the vertical plate 27 at this speed, thus determining the current crystal precipitation status. When the displacement sensor detects a small deflection angle of the vertical plate 27, it indicates that the resistance experienced by the vertical plate 27 during its circumferential movement within the solution is small. This situation only occurs when the viscosity of the solution is low, indicating that the amount of crystal precipitation inside the lower vessel 12 is low. Therefore, the power component 1 needs to be controlled to increase its rotation speed to improve the mixing rate inside the lower vessel 12 and accelerate crystal precipitation. When the displacement sensor detects a large deflection angle of the vertical plate 27, it indicates that the viscosity of the internal solution is gradually increasing, making mixing more difficult. At this point, the rotation speed should not be blindly increased to improve mixing efficiency, as the operating resistance experienced by the motor is greater, which will affect the lifespan of the power component 1.

[0056] When the displacement sensor detects a gradual increase in the viscosity of the solution inside the lower vessel 12, the rotation speed of the shaft 18 needs to be gradually reduced to lessen the resistance on the power assembly 1 and extend its lifespan. However, reducing the rotation speed of the shaft 18 will decrease the centrifugal force on the vertical plate 27, resulting in a smaller deflection angle or no deflection at all. This leads to a larger contact area between the vertical plate 27 and the liquid during rotation, increasing the operating resistance of the power assembly 1. At this point, the electromagnet 31 inside the control cavity generates a magnetic force opposite to that of the fixed magnet 32. The electromagnet 31 uses this magnetic force to push the fixed magnet 32 ​​downward, causing the cylindrical rod 22 to move downward, thus simultaneously extending the telescopic rod 24 outward. This, combined with the first connecting rod 25 and the second connecting rod 26, pulls the vertical plate 27 to rotate, ensuring that the vertical plate 27 makes contact with the solution during its circumferential movement. The change in contact angle reduces the resistance of the solution to the vertical plate 27, extending the life of the power component 1. The reduction in the rotation speed of the shaft 18 will reduce the overall mixing rate inside the lower vessel 12 to some extent, affecting the crystal precipitation effect. The electromagnet 31 is controlled to rapidly change its magnetic poles, driving the fixed magnet 32 ​​to rapidly reciprocate up and down. By increasing the swing amplitude of the vertical plate 27 and the extension amplitude of the telescopic rod 24, and simultaneously increasing the extension frequency of the cylinder 28 at the lower end of the shaft 18, the suction rate of the cylinder 28 for the solution at the bottom of the lower vessel 12 is accelerated. The greater the movement amplitude and the faster the movement speed of the fixed magnet 32, the greater the force of the solution ejected by the conical head 29, which can effectively accelerate the flow speed of the solution inside the lower vessel 12. This ensures that even with the reduction in the rotation speed of the shaft 18, the load on the power component 1 can be reduced without reducing the mixing rate of the solution inside the lower vessel 12.

[0057] When the shaft 18 is at the detection speed, the displacement sensor detects that the deflection angle of the vertical plate 27 is large. When it reaches the preset deflection angle, it indicates that the crystal precipitation inside the solution is complete. However, during the crystallization process, crystals may first appear on the side wall of the lower vessel 12. The side wall cannot be cleaned during the discharge process, resulting in crystal residue. The electromagnet 31 is controlled to generate a magnetic force with the same magnetic pole as the fixed magnet 32, causing the fixed magnet 32 ​​to drive the cylindrical rod 22 to move downward, thus moving the vertical plate 27 outward and rotating it at the same time. As the magnetic force of the fixed magnet 32 ​​continues to increase, when the displacement sensor detects that the cylindrical rod 22 no longer moves, it indicates that the vertical plate 27 has stopped moving. The outer side of 27 contacts the inner wall of the lower vessel 12. At this point, there is no need to continue adjusting the magnetic force of the electromagnet 31. As the cylindrical rod 22 descends, it will drive the cylinder 28 to descend, causing the slurry plates 30 on both sides to descend synchronously, so that the bottom of the slurry plates 30 contacts the bottom of the vessel. At the same time, the conical head 29 can extend into the interior of the feed pipe 15. On the one hand, it can clear the feed pipe 15, and on the other hand, it can not affect the contact between the ground of the slurry plate 30 and the lower vessel 12. Then, the shaft 18 is controlled to rotate. The inclined vertical plate 27 can better remove the crystals inside the lower vessel 12 and reduce the wear of the crystals on the vertical plate 27. It can also scrape off the crystals at the bottom of the lower vessel 12.

[0058] After the crystal residue is scraped off, the crystal slurry discharge operation can begin. Open the valve inside the discharge pipe 15 to allow the crystal slurry inside the lower vessel 12 to flow downwards. During the discharge process, the shaft 18 rotates slowly to prevent sedimentation at the bottom of the lower vessel 12. If the discharge port becomes blocked during the discharge process, the magnetic poles of the electromagnet 31 are switched to drive the fixed magnet 32 ​​to move rapidly, thereby achieving rapid movement of the cylinder 28. The space between the cylinder 28 and the lower end of the shaft 18 changes drastically, resulting in a rapid liquid pumping and spraying action to impact and clear the blockage at the discharge port.

[0059] It should be noted that the tilt angle of the vertical plate 27 can be identified by the displacement sensor in conjunction with the specific rotation speed of the shaft 18, thereby determining the crystallization effect of the solution inside the lower vessel 12. The rotation speed of the shaft 18 is adjusted accordingly. If the crystallization efficiency is low, the rotation speed of the shaft 18 is increased; if the crystallization efficiency is high, the rotation speed of the shaft 18 is decreased. At the same time, the changes in the magnetic poles and magnetic force of the electromagnet 31 are controlled to change the tilt angle of the vertical plate 27. On the one hand, this reduces the resistance borne by the power component 1, and on the other hand, it intensifies the movement and oscillation frequency of the vertical plate 27, ensuring the stability of the stirring efficiency. Through the cooperation of the displacement sensor and the electromagnet 31, the movement of the vertical plate 27 and the slurry plate 30 is controlled to complete the scraping of the crystal residue on the inner wall of the lower vessel 12. At the same time, when the crystal slurry is blocked at the discharge port, the change in the magnetic poles of the electromagnet 31 is intensified to achieve rapid movement of the cylinder 28, performing rapid liquid pumping and spraying actions to impact and clear the blockage at the discharge port.

[0060] Example 3:

[0061] A method for preparing salicylaniline from phosgene by crystallization, comprising the following steps:

[0062] S1: Add solution into the upper vessel body 6 and the lower vessel body 12, and drive the shaft 18 to rotate through the power component 1;

[0063] S2: The shaft 18 drives the vertical plate 27 and the paddle plate 30 to rotate. While the shaft 18 rotates, the angle of the vertical plate 27 deflects. The height of the paddle plate 30 changes while the shaft 18 rotates. The impact component intermittently impacts the bottom of the lower vessel 12 to prevent blockage while the shaft 18 rotates.

[0064] S3: The displacement sensor identifies the deflection angle of the vertical plate 27 during rotation, detects the degree of reaction of the solution inside the lower vessel 12, and adjusts the rotation speed of the power component 1 and the operating frequency of the impact component accordingly.

[0065] S4: The crystallized solution is discharged from the lower vessel 12 through the feed pipe 15, and the solution is transported through the discharge pipe 16.

[0066] By using a displacement sensor in conjunction with the vertical plate 27, the crystallization effect of the solution inside the lower vessel 12 can be identified at a specific rotational speed of the shaft 18. The rotational speed of the shaft 18 is then adjusted accordingly. Poor crystallization efficiency corresponds to increasing the rotational speed of the shaft 18, while good crystallization efficiency corresponds to decreasing the rotational speed of the shaft 18. At the same time, the changes in the magnetic poles and magnetic force of the electromagnet 31 are controlled to change the tilt angle of the vertical plate 27. This reduces the resistance borne by the power component 1 and intensifies the movement and oscillation frequency of the vertical plate 27, ensuring stable stirring efficiency. By using a displacement sensor in conjunction with the electromagnet 31, the movement of the vertical plate 27 and the slurry plate 30 is controlled, completing the scraping of crystal residue on the inner wall of the lower vessel 12. At the same time, when the crystal slurry is detected to be blocked at the discharge port, the changes in the magnetic poles of the electromagnet 31 are intensified to achieve rapid movement of the cylinder 28, performing rapid liquid pumping and spraying actions to impact and clear the blockage at the discharge port. The crystallized slurry is discharged from the interior of the lower vessel 12 through the discharge pipe 15 and then undergoes further filtration and drying through the discharge pipe 16.

Claims

1. A crystallization apparatus for the clean production of salicylnitrile from phosgene, comprising an upper vessel and a lower vessel, characterized in that: The upper and lower vessels are connected to each other. The upper vessel is equipped with a power assembly at its upper end. The lower vessel is equipped with a cooling assembly on its outer side and a support assembly on its outer side. The lower vessel is equipped with a feeding assembly at its bottom and a mixing assembly inside the lower vessel. The mixing assembly is equipped with an impact assembly at its bottom. The mixing assembly includes a shaft, with two sleeves located in the middle of the shaft. The two sleeves are symmetrically arranged about the center of the shaft. A telescopic rod is slidably connected inside the sleeves, and a vertical plate is hinged to the outside of the telescopic rod. A first connecting rod is located at the top of the outer side of the sleeve, and a second connecting rod is located outside the first connecting rod. The second connecting rod is fixedly connected to the vertical plate. A slider is slidably connected inside the shaft, and two inclined rods are located outside the slider. The two inclined rods are symmetrically arranged about the center of the shaft, and the inclined rods are connected to the outer ends of the telescopic rod. The impact assembly includes a cylindrical body, a cylindrical rod at the bottom of the slider, the cylindrical rod being slidably connected to the shaft, a cavity at the bottom of the shaft, an electromagnet at the top of the cavity, the cylindrical rod passing through the electromagnet, a fixed magnet at the bottom of the cylindrical rod, the fixed magnet being slidably connected to the shaft, a displacement sensor at one side of the fixed magnet, a support plate at the lower end of the fixed magnet, the bottom of the support plate being connected to the cylindrical body, and a conical head at the bottom of the cylindrical body.

2. The crystallization equipment for the clean production of salicylnitrile from phosgene according to claim 1, characterized in that: A spring is fitted onto the outer side of the top of the cylindrical rod. One end of the spring is connected to the bottom of the slider, and the other end of the spring is connected to the shaft.

3. The crystallization equipment for the clean production of salicylnitrile from phosgene according to claim 1, characterized in that: The outer side of the fixed magnet has several round holes evenly arranged, and the outer side of the cylinder is provided with two paddle plates, which are arranged symmetrically.

4. The crystallization equipment for the clean production of salicylnitrile from phosgene according to claim 1, characterized in that: The power assembly includes a motor, a reducer is provided at the bottom of the motor, a transmission rod is provided at the bottom of the reducer, the top of the transmission rod passes through the upper vessel body, and the bottom of the transmission rod is connected to the top of the shaft body.

5. The crystallization equipment for the clean production of salicylnitrile from phosgene according to claim 1, characterized in that: The cooling assembly includes a jacket, which is connected to the outside of the lower vessel body. Cooling pipes are provided inside the jacket and the lower vessel body, and the cooling pipes are spirally arranged inside the jacket.

6. The crystallization equipment for the clean production of salicylnitrile from phosgene according to claim 5, characterized in that: The bottom of the cooling tube is connected to a water inlet pipe, and the top of the cooling tube is connected to a water outlet pipe. The water inlet pipe and the water outlet pipe penetrate the side wall of the lower vessel.

7. The crystallization equipment for the clean production of salicylnitrile from phosgene according to claim 5, characterized in that: The support assembly includes several frames, which are evenly arranged on the outside of the sleeve. The inside of each frame is provided with a support leg, and the bottom of each support leg is provided with a base plate.

8. The crystallization equipment for the clean production of salicylnitrile from phosgene according to claim 1, characterized in that: The upper vessel body is provided with a feed pipe on one side of the top, and a cover plate is provided at the top of the feed pipe. The upper vessel body is provided with a liquid replenishment pipe on the other side, and a screw cap is provided at the top of the liquid replenishment pipe.

9. A crystallization apparatus for the clean production of salicylnitrile from phosgene according to claim 5, characterized in that: The feeding assembly includes a feeding pipe, the top of which is connected to the bottom of the lower vessel body, the feeding pipe passes through the bottom of the jacket, and a discharge pipe is provided at the bottom of the feeding pipe.

10. A crystallization method for preparing salicylate from phosgene, wherein the crystallization method utilizes a crystallization apparatus for clean production of salicylate from phosgene as described in claim 9 to achieve solution crystallization, characterized in that... Includes the following steps: S1: Add solution to the upper and lower vessel bodies, and drive the shaft to rotate via the power assembly; S2: The shaft drives the vertical plate and the paddle plate to rotate. While the shaft rotates, the angle of the vertical plate deflects. The height of the paddle plate changes while the shaft rotates. The impact component intermittently impacts the bottom of the lower vessel to prevent blockage while the shaft rotates. S3: The displacement sensor identifies the deflection angle of the vertical plate during rotation, detects the degree of reaction of the solution inside the lower vessel, and adjusts the rotation speed of the power component and the operating frequency of the impact component accordingly. S4: The crystallized solution is discharged from the lower reactor body through the feed pipe, and the solution is transported through the discharge pipe.

Images