Chloroacetic acid reaction device with defoaming function and method

Abstract

The present application relates to chloroacetic acid reaction device technical field, and disclose a kind of chloroacetic acid reaction device with defoaming function, including reaction kettle body, reaction kettle cover and the stirring rod in reaction kettle body and reaction kettle cover, the stirring rod outside is fixedly installed with multiple groups of stirring vane, the present application when stirring rod passes through stirring vane and is mixed to reactant, stirring rod drives slider synchronous rotation, slider drives each sector housing rotation along the circumferential direction of reaction kettle body, sector housing in the process of rotation, its open end is constantly collected to sector housing by foam generated at liquid level, by the cooperation of horizontal groove and arc groove, realize periodic lifting motion, so that it repeatedly experiences the switching of " completely sink below liquid level " and " part is located above liquid level " two states in the process of rotation, when sector housing sinks below liquid level, the foam collected in its cavity is directly contacted with reaction liquid, rapidly dissolved or broken under the action of stirring, realize the instant melting of foam.

Description

Technical Field

[0001] This invention relates to the field of chloroacetic acid reaction apparatus technology, specifically to a chloroacetic acid reaction apparatus and method with a defoaming function. Background Technology

[0002] Methyl chloroacetate is an important organic chemical intermediate widely used in pesticides, pharmaceuticals, dyes, and solvents. Currently, its industrial production mainly involves reacting chloroacetic acid with methanol in a reactor to produce methyl chloroacetate and water. Since methyl chloroacetate, water, and methanol form a ternary azeotropic mixture under the reaction conditions, the azeotropic vapor is removed from the reaction system by distillation during the reaction process. After condensation, it enters an ester-water separator for separation, thereby promoting the forward reaction.

[0003] In the reaction of chloroacetic acid and methanol, foam generation is a significant issue affecting reaction efficiency and stable equipment operation. Analysis of raw material characteristics shows that when chloroacetic acid (solid) and methanol (liquid) are directly mixed, the surface of the solid particles dissolves rapidly upon contact, displacing surrounding air and generating a small number of bubbles on the liquid surface. However, these bubbles are temporary physical air releases and usually disappear quickly. However, when the raw materials contain impurities or moisture, the foaming problem is significantly aggravated. If the methanol contains water or the chloroacetic acid is damp, the chloroacetic acid partially hydrolyzes in the presence of trace amounts of water, releasing hydrogen chloride gas. This gas has limited solubility in methanol and escapes from the liquid surface as tiny bubbles. Furthermore, industrial-grade chloroacetic acid may contain impurities such as dichloroacetic acid, sulfates, or unreacted acetic acid, while methanol may contain impurities such as aldehydes. These impurities easily form surface-active substances under acidic heating conditions, significantly reducing the surface tension of the liquid and leading to the generation of a large amount of stable foam during the reaction.

[0004] To address the aforementioned foaming problem, current methods mostly involve adding defoaming agents, spraying with water to defoam, or using traditional demisters (such as cyclone demisters). However, while adding defoaming agents to the reaction system can quickly break up foam, these agents, as foreign impurities, are difficult to separate from methyl chloroacetate and will remain in the product, affecting product quality and interfering with subsequent distillation separation processes. Spraying water to impact and break up the foam can also be effective, but the introduction of water will directly dilute the reactants. The esterification reaction of chloroacetic acid and methanol is a reversible reaction, and the water generated in the reaction itself has an inhibitory effect on the reaction equilibrium. The additional water introduced will further disrupt the reaction equilibrium, reduce the conversion rate of chloroacetic acid, and increase the energy consumption of subsequent distillation and dehydration. For cyclone demisters, foam is drawn from the surface of the reaction liquid to the upper part of the equipment for liquid-foam separation. However, in a relatively closed reaction vessel, the drawn-out foam tends to accumulate above the demister, forming a foam layer. The presence of the foam layer hinders the mass transfer process between the gas phase (methanol vapor and water vapor generated in the reaction) and the liquid phase. Since the esterification reaction is a reversible reaction, the water generated in the reaction needs to be removed from the system in a timely manner to promote the forward reaction. After the foam "seals" the liquid surface, the water is not easily carried out by the methanol vapor, resulting in a decrease in reaction conversion rate and a prolongation of reaction time. More seriously, when the foam expands rapidly, its volume may increase several times rapidly. If the space reserved in the reaction vessel is insufficient, the foam may rush out from the feed port or condenser interface, causing material loss, equipment contamination, or even safety accidents. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a chloroacetic acid reaction apparatus and method with a defoaming function, aiming to solve the technical problem that large amounts of foam accumulate during the existing chloroacetic acid reaction process, making it difficult to eliminate and affecting reaction efficiency and operational safety.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a chloroacetic acid reaction device with defoaming function, comprising a reaction vessel body, a reaction vessel cover, and a stirring rod located inside the reaction vessel body and the reaction vessel cover. Multiple sets of stirring blades are fixedly installed on the outer side of the stirring rod. A slider is slidably fitted onto the stirring rod at the connection between the reaction vessel body and the reaction vessel cover. Multiple fan-shaped shells for collecting foam are fixedly installed around the slider. Filter screens are installed on the upper, lower, and rear sides of each fan-shaped shell. A connecting component for repeatedly raising and lowering the fan-shaped shells is installed inside the reaction vessel cover. The raising and lowering of the connecting component is used to defoam the collected foam. A spray assembly for defoaming is fixedly installed on the stirring rod. A cavity is opened inside the stirring rod, and a pull-out assembly is provided inside the cavity. The pull-out assembly is used to draw liquid from the reaction vessel body into the spray assembly. One end of the pull-out assembly is connected to the slider. A first shell is fixedly fitted onto the outer side of the reaction vessel body. An inlet and an outlet are fixedly connected to the outer side of the first shell. An observation window is provided on the reaction vessel cover.

[0007] Preferably, the reactor also includes a speed reducer installed on the reactor lid, the speed reducer being equipped with a stepper motor, and the upper end of the stirring rod passing through the reactor lid and connected to the speed reducer.

[0008] Preferably, the connector includes a fixing ring fixedly installed on the inner wall of the reactor lid. The fixing ring has multiple horizontal grooves and arc-shaped grooves evenly spaced on its inner side. The multiple horizontal grooves and arc-shaped grooves are alternately arranged and interconnected. The arc-shaped surface of the fan-shaped shell is equipped with a sliding rod that is slidably connected to the horizontal grooves and arc-shaped grooves.

[0009] Preferably, the spray assembly includes a spiral tube fixedly mounted on a stirring rod, the spiral tube having multiple liquid outlet holes on one side of the fan-shaped housing, and the spiral diameter of the spiral tube gradually decreasing from bottom to top.

[0010] Preferably, a second shell is fixedly fitted on the outside of the reactor body, the second shell being located outside the first shell, and the outside of the second shell is fixedly connected to an inlet and an outlet.

[0011] Preferably, the pull-out assembly includes a piston slidably connected to the cavity, a pull rod fixedly installed through the piston, the lower end of the pull rod being threadedly connected to the slider, a placement port being opened through one side of the stirring rod, an outlet pipe and an inlet pipe being installed through the upper wall of the placement port, one end of the outlet pipe being fixedly connected to the cavity and the other end being fixedly connected to the spiral tube, one end of the inlet pipe being fixedly connected to the cavity and the other end being fixedly connected to a filter ball below the liquid surface, and a one-way valve being fixedly installed at one end of the outlet pipe and the inlet pipe at the cavity.

[0012] Preferably, the spiral tube, the outlet tube, and the inlet tube are all rigid tubes.

[0013] Preferably, the stirring rod has a sliding opening on its outer side, the slider is slidably connected to the sliding opening, a guide rod is fixedly installed at the bottom of the sliding opening, and a guide groove is provided at the lower end of the slider, which is slidably connected to the guide rod.

[0014] A defoaming method for a chloroacetic acid reaction apparatus with defoaming function includes the following steps:

[0015] Step 1: Reaction preparation and initial state confirmation

[0016] The operator adds chloroacetic acid and methanol into the reactor body according to the ratio, and then confirms the position of the reaction liquid level through the observation window to ensure that the initial position of the fan-shaped shell is at the liquid level interface. The heat source is introduced into the interlayer between the first shell and the reactor body through the inlet to heat the reactor body. The heat source is circulated out through the outlet.

[0017] Step 2: Stirring and Reaction Start-up

[0018] The stepper motor is started, and after being reduced in speed by the reducer, it drives the stirring rod to rotate. The stirring rod drives multiple sets of stirring blades to mix and stir the reactants, accelerating the dissolution of chloroacetic acid and the esterification reaction. The methyl chloroacetate, water and unreacted methanol produced by the reaction form a ternary azeotropic mixture.

[0019] Step 3: Foam collection and primary defoaming

[0020] When the stirring rod rotates, it drives the slider to rotate synchronously. The slider drives each sector shell to rotate around the circumference of the reactor body. During the rotation, the opening end of the sector shell continuously collects the foam generated at the liquid surface into the sector shell. As the sector shell rotates with the stirring rod, the sliding rod on its arc surface slides along the horizontal groove and arc groove inside the fixed ring. When the sliding rod is in the horizontal groove, the lower end of the sector shell is submerged below the liquid surface and the upper end is exposed above the liquid surface. Its opening end continuously collects foam. When the sliding rod slides into the bottom of the arc groove, the sector shell is completely submerged below the liquid surface. The foam collected in its cavity comes into direct contact with the reaction liquid and dissolves rapidly under the stirring action.

[0021] Step 4: Secondary Defoaming

[0022] While the fan-shaped shell collects defoaming, the pull-out component draws the reaction liquid in the reactor to the spiral tube. The liquid is sprayed downward from the liquid outlet to form a liquid curtain, which performs secondary impact defoaming on the liquid surface and foam layer below.

[0023] Step 5: Self-circulation of defoaming solution

[0024] When the slide rod drives the sector-shaped shell to reciprocate up and down under the guidance of the arc groove, the sector-shaped shell drives the slider to reciprocate up and down synchronously along the sliding port on the stirring rod. The slider drives the piston to reciprocate up and down in the cavity through the pull rod. When the piston rises, the reaction liquid inside the reactor body is sucked into the cavity through the liquid inlet pipe. The filter ball at the end of the liquid inlet pipe is used to filter solid particles. When the piston falls, the sucked reaction liquid is pressed into the spiral tube through the liquid outlet pipe and sprayed out from the liquid outlet hole to form a defoaming liquid curtain. The one-way valves at the ends of the liquid outlet pipe and the liquid inlet pipe ensure that the liquid flows in one direction and prevents backflow.

[0025] Step 6: Reaction process monitoring and emergency cooling

[0026] Operators monitor the reaction liquid level and foam status in real time through the observation window. Under normal circumstances, the reaction continues at the set temperature and the foam is removed in time. If the foam increases abnormally due to reasons such as the raw materials being damp, the operator will shut off the heat source input of the first shell and introduce cooling medium into the second shell through the liquid inlet. The cooling medium is circulated out through the liquid outlet to quickly cool the reaction vessel. At this time, the stepper motor keeps running at a low speed to ensure that the solid chloroacetic acid continues to dissolve and prevent clumping.

[0027] Step 7: Reaction ends

[0028] Once the reaction is complete, stop heating.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. To collect and treat foam promptly at the initial stage of the reaction, preventing its accumulation and subsequent difficulty in elimination, and to achieve continuous dynamic foam removal, this invention features an innovative foam collection structure. Specifically, multiple sector-shaped shells for collecting foam are fixedly installed around the slider on the stirring rod. When the stirring rod mixes and stirs the reactants with the stirring blades, the stirring rod drives the slider to rotate synchronously. The slider then drives each sector-shaped shell to rotate circumferentially around the reaction vessel. During rotation, the open ends of the sector-shaped shells continuously collect foam generated at the liquid surface into the sector-shaped shells. As the sector-shaped shells rotate with the stirring rod, they are collected horizontally... The combination of the trough and the arc-shaped trough enables periodic lifting and lowering motion, causing it to repeatedly switch between two states during rotation: "completely submerged below the liquid surface" and "partially above the liquid surface." When the fan-shaped shell is submerged below the liquid surface, the foam collected in its cavity comes into direct contact with the reaction liquid and quickly dissolves or breaks down under the stirring action, achieving immediate foam dissolution. When the fan-shaped shell is partially exposed above the liquid surface, its open end collects foam again, realizing a continuous processing mode of "immediate production, immediate collection, and immediate elimination" of foam. Foam collection begins from the initial stage of the reaction, avoiding the problem of foam accumulation that is difficult to eliminate, and controlling foam in its nascent stage.

[0031] 2. To further enhance defoaming of residual or newly formed foam based on the defoaming collection in the fan-shaped shell, this invention fixes a spiral tube to the stirring rod. The spiral tube extends upward along the stirring rod axis, and its wall is evenly distributed with multiple liquid outlet holes. With the cooperation of the pull assembly, the reaction liquid in the reactor is pumped into the spiral tube. The liquid is sprayed downward from the liquid outlet holes in the spiral tube, forming a liquid curtain, which performs secondary impact defoaming on the liquid surface and foam layer below. The spiral tube adopts a variable diameter structure, with its spiral diameter gradually decreasing from bottom to top. The lower large-diameter spiral covers the foam in the edge area of ​​the reactor, while the upper small-diameter spiral concentrates on covering the central area, so that the defoaming range covers the reactor layer by layer from the edge to the center, resulting in a more comprehensive and uniform coverage area. Moreover, the sprayed reaction liquid comes directly from inside the reactor and is completely consistent with the composition of the reaction system, without introducing any foreign impurities, and does not affect the reaction balance or product quality.

[0032] 3. This invention integrates the internal structure of the stirring rod, creating an axial cavity within the rod. A piston slides within this cavity, with a connecting rod threadedly connected to the slider. As the slider reciprocates with the stirring rod under the guidance of the arc groove, the connecting rod simultaneously drives the piston to reciprocate within the cavity. When the piston rises, the reaction liquid inside the reactor is drawn into the cavity through the inlet pipe. When the piston descends, the drawn-in reaction liquid is pumped through the outlet pipe to the spiral tube, where it is sprayed out through the outlet hole, forming a defoaming liquid curtain. The automatic suction and circulation of the defoaming liquid is achieved using the rotational power of the stirring rod itself, avoiding the increased energy consumption and structural complexity associated with adding an external circulation pump. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the present invention;

[0034] Figure 2 This is a schematic diagram of the overall and partial three-dimensional structure of the present invention;

[0035] Figure 3 for Figure 2 A magnified structural diagram of A in the middle;

[0036] Figure 4 This is a three-dimensional cross-sectional schematic diagram of the reactor lid of the present invention;

[0037] Figure 5 This is a three-dimensional structural diagram showing the disassembled fixing ring and sector-shaped housing of the present invention;

[0038] Figure 6 This is a three-dimensional cross-sectional structural diagram of the stirring rod of the present invention;

[0039] Figure 7 for Figure 6 A magnified structural diagram of B in the diagram;

[0040] Figure 8 This is a three-dimensional structural diagram of the slider and stirring rod of the present invention.

[0041] In the diagram: 1. Reactor lid; 2. Stepper motor; 3. Reducer; 4. First shell; 5. Stirring blade; 6. Stirring rod; 7. Fixing ring; 8. Filter screen; 9. Reactor body; 10. Outlet; 11. Liquid inlet; 12. Second shell; 13. Inlet; 14. Liquid outlet; 15. Sliding rod; 16. Horizontal groove; 17. Fan-shaped shell; 18. Arc-shaped groove; 19. Spiral tube; 20. Placement port; 21. Piston; 22. Cavity; 23. Liquid outlet pipe; 24. Liquid inlet pipe; 25. Pull rod; 26. Filter ball; 27. Sliding port; 28. Sliding block; 29. ​​Guide groove; 30. Guide rod; 31. Liquid outlet hole; 32. Observation window. Detailed Implementation

[0042] The embodiments of this disclosure will be further described in detail below with reference to the accompanying drawings and examples. The detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of this disclosure by way of example, but should not be used to limit the scope of this disclosure. This disclosure can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0043] Please see Figures 1-8 A chloroacetic acid reaction apparatus with defoaming function includes a reaction vessel body 9, a reaction vessel cover 1, and a stirring rod 6 located inside the reaction vessel body 9 and the reaction vessel cover 1. It also includes a reducer 3 installed on the reaction vessel cover 1, a stepper motor 2 installed on the reducer 3, the housing of the reducer 3 being fixedly connected to the reaction vessel cover 1, the stepper motor 2 being fixedly installed on the housing of the reducer 3, the upper end of the stirring rod 6 penetrating through the reaction vessel cover 1 and connected to the reducer 3, and multiple sets of stirring blades 5 being fixedly installed on the outside of the stirring rod 6 (starting the stepper motor 2 controls the rotation of the stirring rod 6, driving the stirring blades 5 to mix and stir the reactants, thereby accelerating the reaction rate). A first shell 4 is fixedly sleeved on the outside of the reaction vessel body 9, and an inlet 13 and an outlet 10 are fixedly connected on the outside of the first shell 4. A heat source is input through the inlet 13 into the space between the first shell 4 and the reaction vessel body 9 to heat the reaction, and then the heat source is transported through the outlet 10.

[0044] A slider 28 is slidably mounted on the stirring rod 6 at the connection between the reactor body 9 and the reactor cover 1. To collect and process foam promptly at the initial stage of the reaction, preventing excessive foam accumulation and ensuring continuous dynamic cleaning, the present invention has multiple fan-shaped shells 17 fixedly installed around the slider 28 for collecting foam. (The stirring rod 6 has a sliding opening 27 on its outer side; the slider 28 is slidably connected to the sliding opening 27; a guide rod 30 is fixedly installed at the bottom of the sliding opening 27; and a guide groove 29 is slidably connected to the guide rod 30 at the lower end of the slider 28.) The upper side of the fan-shaped shell 17... Filter screens 8 are installed on both the lower and rear sides. A connector for controlling the repeated lifting and lowering of the fan-shaped housing 17 is installed inside the reactor lid 1. The lifting and lowering of the connector is used to defoam the collected foam. The connector includes a fixing ring 7 fixedly installed on the inner wall of the reactor lid 1. Multiple horizontal grooves 16 and arc-shaped grooves 18 are equally spaced on the inner side of the fixing ring 7. The multiple horizontal grooves 16 and arc-shaped grooves 18 are alternately arranged and interconnected. A slide rod 15 is installed on the arc-shaped surface of the fan-shaped housing 17 and is slidably connected to the horizontal grooves 16 and arc-shaped grooves 18. When the slide rod 15 is located in the horizontal groove 16, the lower end of the fan-shaped housing 17 is located at... With the upper end below the liquid surface and the lower end above the liquid surface, and the slide rod 15 at the bottom of the arc-shaped groove 18, the sector-shaped shell 17 is completely submerged below the liquid surface. When the stirring rod 6 mixes and stirs the reactants through the stirring blades 5, the stirring rod 6 drives the slider 28 to rotate synchronously. The slider 28 drives each sector-shaped shell 17 to rotate circumferentially along the reactor body 9. During the rotation, the opening end of the sector-shaped shell 17 continuously collects the foam generated at the liquid surface into the sector-shaped shell 17. As the sector-shaped shell 17 rotates with the stirring rod 6, it achieves periodic lifting and lowering motion through the cooperation of the horizontal groove 16 and the arc-shaped groove 18, making... During its rotation, it repeatedly switches between two states: "completely submerged below the liquid surface" and "partially above the liquid surface". When the fan-shaped shell 17 is submerged below the liquid surface, the foam collected in its cavity comes into direct contact with the reaction liquid and quickly dissolves or breaks under the stirring action, achieving instant foam dissolution. When the fan-shaped shell 17 is partially exposed above the liquid surface, its open end collects foam again, realizing a continuous processing mode of "immediate production, immediate collection, and immediate elimination" of foam. Foam collection begins from the initial stage of the reaction, avoiding the problem of foam being difficult to eliminate after a large amount of foam accumulates, and controlling the foam in its nascent stage.

[0045] A defoaming spray assembly is fixedly installed on the stirring rod 6. A cavity 22 is formed inside the stirring rod 6, and a pull-out assembly is installed within the cavity 22. The pull-out assembly is used to draw the liquid inside the reactor body 9 into the spray assembly. One end of the pull-out assembly is connected to a slider 28. The spray assembly includes a spiral tube 19 fixedly installed on the stirring rod 6. The spiral tube 19 has multiple liquid outlet holes 31 on one side of the fan-shaped shell 17. With the cooperation of the pull-out assembly, the reaction liquid inside the reactor body 9 is drawn into the spiral tube 19. The liquid is sprayed downwards from the liquid outlet holes 31 within the spiral tube 19, forming a liquid curtain that sprays downwards. The liquid surface and foam layer undergo secondary impact defoaming. The spiral tube 19 gradually decreases in diameter from bottom to top. The lower large-diameter spiral covers the foam in the edge area of ​​the reactor body 9, while the upper small-diameter spiral concentrates on covering the central area. This allows the defoaming range to cover the reactor body 9 layer by layer from the edge to the center, resulting in a more comprehensive and uniform coverage area. Furthermore, the sprayed reaction liquid comes directly from inside the reactor body 9 and is completely consistent with the composition of the reaction system, without introducing any foreign impurities, thus not affecting the reaction balance or product quality. Based on the defoaming collected by the fan-shaped shell 17, secondary enhanced defoaming is performed on the residual or newly generated foam.

[0046] As a further technical solution of the present invention, an observation window 32 is provided on the reactor cover 1, and a second shell 12 is fixedly sleeved on the outside of the reactor body 9. The second shell 12 is located outside the first shell 4, and an inlet 11 and an outlet 14 are fixedly connected to the outside of the second shell 12. In case of sudden problems, such as if chloroacetic acid is severely damp and not detected in time, it will be put into the reactor body 9, which will produce a lot of foam. A lot of foam can be seen through the observation window 32. At this time, it is necessary to cool down immediately. This can be done by turning off the heat source input, inputting the cooling medium into the second shell 12 through the inlet 11, and then outputting it from the outlet 14. At this time, the stepper motor 2 still needs to keep running at a low speed. Stirring cannot be stopped when the solid chloroacetic acid has not completely dissolved, otherwise it will cause clumping. At this time, the stirring rod 6 continues to run to cooperate with defoaming.

[0047] As a further technical solution of the present invention, the pull-out assembly includes a piston 21 slidably connected to the cavity 22. A pull rod 25 is fixedly installed through the piston 21. The lower end of the pull rod 25 is threadedly connected to the slider 28. A placement port 20 is opened through one side of the stirring rod 6. An outlet pipe 23 and an inlet pipe 24 are installed through the upper wall of the placement port 20. One end of the outlet pipe 23 is fixedly connected to the cavity 22, and the other end is fixedly connected to the spiral tube 19. One end of the inlet pipe 24 is fixedly connected to the cavity 22, and the other end is fixedly connected to a filter ball 26 below the liquid surface. One-way valves are fixedly installed at one end of the outlet pipe 23 and the inlet pipe 24 at the cavity 22. The spiral tube 19, the outlet pipe 23, and the inlet pipe 24 are all rigid pipes. When the slider 15... Guided by the arc-shaped groove 18, the stirring rod 6 rotates and moves up and down, while the sliding rod 15 drives the fan-shaped shell 17 to move up and down. The fan-shaped shell 17 drives the slider 28 to move up and down. The slider 28 pulls the pull rod 25 to drive the piston 21 to move up and down in the cavity 22. When the piston 21 rises, it draws the reaction liquid inside the reactor body 9 into the cavity 22 through the liquid inlet pipe 24. When the piston 21 falls, it pushes the drawn-in reaction liquid through the liquid outlet pipe 23 to the spiral tube 19, and sprays it out from the liquid outlet hole 31 on the spiral tube 19 to form a defoaming liquid curtain. The automatic suction and circulation of the defoaming liquid is achieved by using the rotational power of the stirring rod 6 itself, avoiding the problems of increased energy consumption and structural complexity caused by adding an external circulation pump.

[0048] A defoaming method for a chloroacetic acid reaction apparatus with defoaming function includes the following steps:

[0049] Step 1: Reaction preparation and initial state confirmation

[0050] The operator adds chloroacetic acid and methanol into the reactor body 9 according to the ratio, confirms the position of the reaction liquid level through the observation window 32, and ensures that the initial position of the fan-shaped shell 17 is at the liquid level interface. The heat source, such as steam or heat transfer oil, is introduced into the interlayer between the first shell 4 and the reactor body 9 through the inlet 13 to heat the reactor body 9. The heat source is circulated out through the outlet 10.

[0051] Step 2: Stirring and Reaction Start-up

[0052] The stepper motor 2 is started, and after being reduced in speed by the reducer 3, it drives the stirring rod 6 to rotate. The stirring rod 6 drives multiple sets of stirring blades 5 to mix and stir the reactants, accelerating the dissolution of chloroacetic acid and the esterification reaction. The methyl chloroacetate, water and unreacted methanol produced by the reaction form a ternary azeotropic mixture. The stirring action of the stirring blades 5 promotes uniform mixing of solid and liquid and accelerates the reaction rate.

[0053] Step 3: Foam collection and primary defoaming

[0054] When the stirring rod 6 rotates, it drives the slider 28 to rotate synchronously. The slider 28 drives each sector-shaped shell 17 to rotate circumferentially along the reactor body 9. During the rotation, the open end of each sector-shaped shell 17 continuously collects the foam generated at the liquid surface into the sector-shaped shell 17. As the sector-shaped shell 17 rotates with the stirring rod 6, the sliding rod 15 on its arc-shaped surface slides along the horizontal groove 16 and the arc-shaped groove 18 inside the fixing ring 7. When the sliding rod 15 is in the horizontal groove 16, the lower end of the sector-shaped shell 17 is submerged below the liquid surface and the upper end is exposed above the liquid surface, and its open end continues to collect foam. When the sliding rod 15 slides into the bottom of the arc-shaped groove 18, the sector-shaped shell... Body 17 is completely submerged below the liquid surface. The foam collected inside its cavity comes into direct contact with the reaction liquid and dissolves or breaks down rapidly under the action of stirring. As the stirring rod 6 rotates continuously, the fan-shaped shell 17 repeatedly undergoes a periodic switch of "collecting foam partially above the liquid surface - dissolving foam completely below the liquid surface", realizing the continuous treatment of foam "immediate production and immediate collection, immediate collection and immediate elimination". The fan-shaped shell 17 starts collecting foam from the initial stage of the reaction, controlling the foam in the bud stage and avoiding the difficulty in eliminating foam after a large amount of foam accumulates. The periodic sinking and floating action makes the collected foam immediately carried below the liquid surface to dissolve, without the need to add defoamer.

[0055] Step 4: Secondary Defoaming

[0056] While the fan-shaped shell 17 collects and defoams, the pull-out assembly draws the reaction liquid inside the reactor body 9 to the spiral tube 19. The spiral tube 19 extends spirally upward along the stirring rod 6, and its tube wall is evenly distributed with multiple liquid outlet holes 31. The liquid is sprayed downward from the liquid outlet holes 31 to form a liquid curtain, which performs secondary impact defoaming on the liquid surface and foam layer below. The spiral tube 19 adopts a variable diameter structure, and its spiral diameter gradually decreases from bottom to top. The lower large diameter spiral covers the foam in the edge area of ​​the reactor body 9, and the upper small diameter spiral concentrates on covering the central area, forming a layer-by-layer coverage from the reactor wall to the center. The secondary enhanced defoaming and the mechanical collection of the fan-shaped shell 17 form a dual defoaming mechanism, which significantly improves the defoaming effect. The variable diameter spiral tube 19 achieves all-round coverage, and the sprayed reaction liquid comes directly from inside the reactor, which is completely consistent with the composition of the reaction system, does not introduce foreign impurities, and does not affect the reaction balance and product quality.

[0057] Step 5: Self-circulation of defoaming solution

[0058] When the slide rod 15 drives the fan-shaped shell 17 to move up and down reciprocally under the guidance of the arc groove 18, the fan-shaped shell 17 drives the slider 28 to move up and down synchronously along the sliding port 27 on the stirring rod 6. The slider 28 drives the piston 21 to move up and down reciprocally in the cavity 22 through the pull rod 25. When the piston 21 rises, the reaction liquid inside the reactor body 9 is sucked into the cavity 22 through the liquid inlet pipe 24. The filter ball 26 at the end of the liquid inlet pipe 24 is used to filter solid particles. When the piston 21 falls, the sucked reaction liquid is pressed into the spiral tube 19 through the liquid outlet pipe 23 and sprayed out from the liquid outlet hole 31 to form a defoaming liquid curtain. The one-way valves at the ends of the liquid outlet pipe 23 and the liquid inlet pipe 24 ensure that the liquid flows in one direction and prevents backflow. This realizes the mechanical linkage between the defoaming liquid circulation system and the stirring, eliminating the need for additional circulation pumps and drive motors, simplifying the equipment structure, reducing manufacturing costs and operating energy consumption.

[0059] Step 6: Reaction process monitoring and emergency cooling

[0060] Operators monitor the reaction liquid level and foam status in real time through observation window 32. Under normal circumstances, the reaction continues at the set temperature, and the foam is cleared in time. If the foam increases abnormally due to reasons such as the raw materials being damp, the operator can detect it in time through observation window 32. When an abnormality occurs, the heat source input of the first shell 4 is turned off, and the cooling medium is introduced into the second shell 12 through the liquid inlet 11. The cooling medium is circulated out through the liquid outlet 14 to quickly cool down the reaction vessel 9. At this time, the stepper motor 2 keeps running at low speed to ensure that the solid chloroacetic acid continues to dissolve and prevent clumping. The second shell 12 provides an independent cooling circuit, which can quickly cool down and control the reaction rate when the foam is abnormal. At this time, the subsequent raw materials can be processed in time to reduce the occurrence of sudden situations in the subsequent esterification reaction.

[0061] Step 7: Reaction ends

[0062] After the reaction is complete, heating is stopped. After the reaction vessel 9 cools down, the reaction liquid is discharged through the bottom outlet. The reaction vessel 9 and the reaction vessel cover 1 are detachably connected, which facilitates subsequent cleaning of the interior.

[0063] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of the invention and should not be construed as limiting the scope of protection of the invention in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of the invention without inventive effort, and these embodiments will all fall within the scope of protection of the claims of the present invention.

Claims

1. A chloroacetic acid reaction apparatus with a defoaming function, comprising a reaction vessel body (9), a reaction vessel cover (1), and a stirring rod (6) located within the reaction vessel body (9) and the reaction vessel cover (1), characterized in that, Multiple sets of stirring blades (5) are fixedly installed on the outside of the stirring rod (6). A slider (28) is slidably sleeved on the stirring rod (6) at the connection between the reactor body (9) and the reactor cover (1). Multiple fan-shaped shells (17) for collecting foam are fixedly installed around the slider (28). Filter plates (8) are installed on the upper, lower and rear sides of the fan-shaped shells (17). A connecting piece is installed inside the reactor cover (1) to control the repeated lifting and lowering of the fan-shaped shells (17). The lifting and lowering of the connecting piece is used to defoam the collected foam. A spray assembly for defoaming is fixedly installed on the stirring rod (6). A cavity (22) is opened inside the stirring rod (6). A pull assembly is provided inside the cavity (22). The pull assembly is used to draw the liquid in the reactor body (9) into the spray assembly. One end of the pull assembly is connected to the slider (28). A first shell (4) is fixedly sleeved on the outside of the reactor body (9). An inlet (13) and an outlet (10) are fixedly connected on the outside of the first shell (4). An observation window (32) is provided on the reactor cover (1).

2. The chloroacetic acid reaction apparatus with defoaming function according to claim 1, characterized in that, It also includes a speed reducer (3) installed on the reactor cover (1), a stepper motor (2) is installed on the speed reducer (3), and the upper end of the stirring rod (6) passes through the reactor cover (1) and is connected to the speed reducer (3).

3. The chloroacetic acid reaction apparatus with defoaming function according to claim 2, characterized in that, The connector includes a fixing ring (7) fixedly installed on the inner wall of the reactor cover (1). The fixing ring (7) has multiple horizontal grooves (16) and arc grooves (18) evenly spaced on its inner side. The multiple horizontal grooves (16) and arc grooves (18) are alternately arranged and interconnected. The arc surface of the fan-shaped shell (17) is equipped with a slide rod (15) that is slidably connected to the horizontal grooves (16) and arc grooves (18).

4. A chloroacetic acid reaction apparatus with defoaming function according to claim 3, characterized in that, The spray assembly includes a spiral tube (19) fixedly installed on the stirring rod (6). The spiral tube (19) has multiple liquid outlet holes (31) on one side of the fan-shaped shell (17). The spiral diameter of the spiral tube (19) gradually decreases from bottom to top.

5. A chloroacetic acid reaction apparatus with defoaming function according to claim 4, characterized in that, The reactor body (9) is also fixedly fitted with a second shell (12), which is located outside the first shell (4). The second shell (12) is fixedly connected to the liquid inlet (11) and the liquid outlet (14).

6. A chloroacetic acid reaction apparatus with defoaming function according to claim 5, characterized in that, The pull-out assembly includes a piston (21) that is slidably connected to the cavity (22). A pull rod (25) is fixedly installed through the piston (21). The lower end of the pull rod (25) is threadedly connected to the slider (28). A placement port (20) is opened through one side of the stirring rod (6). An outlet pipe (23) and an inlet pipe (24) are installed through the upper wall of the placement port (20). One end of the outlet pipe (23) is fixedly connected to the cavity (22), and the other end is fixedly connected to the spiral tube (19). One end of the inlet pipe (24) is fixedly connected to the cavity (22), and the other end is fixedly connected to a filter ball (26) below the liquid surface. A one-way valve is fixedly installed at one end of the outlet pipe (23) and the inlet pipe (24) at the cavity (22).

7. A chloroacetic acid reaction apparatus with defoaming function according to claim 6, characterized in that, The spiral tube (19), the outlet tube (23), and the inlet tube (24) are all rigid tubes.

8. A chloroacetic acid reaction apparatus with defoaming function according to claim 7, characterized in that, The stirring rod (6) has a sliding opening (27) on its outer side. The slider (28) is slidably connected to the sliding opening (27). A guide rod (30) is fixedly installed at the bottom of the sliding opening (27). A guide groove (29) is provided at the lower end of the slider (28) and is slidably connected to the guide rod (30).

9. The defoaming method of a chloroacetic acid reaction apparatus with defoaming function according to claim 8, characterized in that, Includes the following steps: Step 1: Reaction preparation and initial state confirmation The operator puts chloroacetic acid and methanol into the reactor body (9) according to the ratio, and then confirms the position of the reaction liquid level through the observation window (32) to ensure that the initial position of the fan-shaped shell (17) is at the liquid level interface. The heat source is introduced into the interlayer between the first shell (4) and the reactor body (9) through the inlet (13) to heat the reactor body (9). The heat source is circulated out through the outlet (10). Step 2: Stirring and Reaction Start-up Start the stepper motor (2), and after the speed reduction by the reducer (3), drive the stirring rod (6) to rotate. The stirring rod (6) drives multiple sets of stirring blades (5) to mix and stir the reactants, accelerate the dissolution of chloroacetic acid and the esterification reaction. The chloroacetic acid methyl ester, water and unreacted methanol generated by the reaction form a ternary azeotropic mixture. Step 3: Foam collection and primary defoaming When the stirring rod (6) rotates, it drives the slider (28) to rotate synchronously. The slider (28) drives each sector shell (17) to rotate around the reactor body (9). During the rotation, the opening end of the sector shell (17) continuously collects the foam generated at the liquid surface into the sector shell (17). While the sector shell (17) rotates with the stirring rod (6), the sliding rod (15) on its arc surface slides along the horizontal groove (16) and arc groove (18) inside the fixed ring (7). When the sliding rod (15) is in the horizontal groove (16), the lower end of the sector shell (17) sinks below the liquid surface and the upper end is exposed above the liquid surface. Its opening end continuously collects foam. When the sliding rod (15) slides into the bottom of the arc groove (18), the sector shell (17) is completely submerged below the liquid surface. The foam collected in its cavity comes into direct contact with the reaction liquid and dissolves rapidly under the stirring action. Step 4: Secondary Defoaming While the fan-shaped shell (17) collects defoaming, the pull assembly draws the reaction liquid in the reactor body (9) to the spiral tube (19). The liquid is sprayed downward from the liquid outlet (31) to form a liquid curtain, which performs secondary impact defoaming on the liquid surface and foam layer below. Step 5: Self-circulation of defoaming solution When the slide bar (15) drives the fan-shaped shell (17) to move up and down under the guidance of the arc groove (18), the fan-shaped shell (17) drives the slider (28) to move up and down synchronously along the sliding port (27) on the stirring rod (6). The slider (28) drives the piston (21) to move up and down in the cavity (22) through the pull rod (25). When the piston (21) rises, it draws the reaction liquid inside the reactor body (9) into the cavity (22) through the liquid inlet pipe (24). The filter ball (26) at the end of the liquid inlet pipe (24) is used to filter solid particles. When the piston (21) falls, it pushes the drawn reaction liquid through the liquid outlet pipe (23) to the spiral tube (19) and sprays it out from the liquid outlet hole (31) to form a defoaming liquid curtain. The one-way valves at the ends of the liquid outlet pipe (23) and the liquid inlet pipe (24) ensure that the liquid flows in one direction and prevents backflow. Step 6: Reaction process monitoring and emergency cooling The operator monitors the reaction liquid level and foam status in real time through the observation window (32). Under normal circumstances, the reaction continues at the set temperature and the foam is removed in time. If the foam increases abnormally due to the raw material being damp, the operator will turn off the heat source input of the first shell (4) and introduce the cooling medium into the second shell (12) through the liquid inlet (11). The cooling medium is circulated out through the liquid outlet (14) to quickly cool the reaction vessel (9). At this time, the stepper motor (2) keeps running at low speed to ensure that the solid chloroacetic acid continues to dissolve and prevent caking. Step 7: Reaction ends Once the reaction is complete, stop heating.

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