A cracking reactor for the production of 3,3-dimethicone from acetic acid.

Abstract

This utility model relates to the field of chemical reaction equipment technology, and discloses a cracking reactor for the production of 3,3-dimethylacrylic acid by acetic acid cracking. The reactor includes a support platform, a heat-insulating cylinder fixed to the upper part of the support platform, a vertical cylinder fixed to the inner wall of the heat-insulating cylinder, two fixing rings fixed to the inner wall of the vertical cylinder, multiple second air heating rods fixed to one end of the two fixing rings, a reaction cylinder fixed to the inner wall of the two fixing rings, a steam input mechanism disposed on the outer peripheral wall of the vertical cylinder for injecting steam into the reaction cylinder, a lifting mechanism disposed on the upper part of the support platform, a lifting column disposed at the output end of the lifting mechanism, a pressure plate fixed to the lower end of the lifting column, a second liquid inlet pipe fixed to the lower end of the pressure plate, and a third valve body disposed on the second liquid inlet pipe. This utility model has the advantages of precise temperature control, flexible feeding, good separation effect, and improved reaction efficiency and product quality.

Description

Technical Field

[0001] This utility model relates to the field of chemical reaction equipment technology, specifically a cracking reactor for the production of 3,3-dimethylacrylic acid by acetic acid cracking. Background Technology

[0002] Currently, in the chemical production field, the acetic acid cracking process to produce 3,3-dimethylacrylic acid is a common synthesis process. Its core equipment is the cracking reactor. Existing cracking reactors typically employ a single-layer cylindrical structure, using an external jacket or internal coil to introduce a heat transfer medium for heating, causing the raw material acetic acid to undergo a cracking reaction at high temperatures. During the reaction, to promote gas-liquid contact and heat transfer, some equipment is equipped with mechanical stirring or airflow disturbance devices. After the reaction is complete, the product is discharged through the bottom outlet.

[0003] However, the main problems with existing reactors are as follows: First, the heating method is singular and the temperature control precision is insufficient. Traditional jacket heating easily leads to local overheating of the cylinder wall, while the internal material temperature distribution is uneven, making it difficult to meet the strict temperature control requirements of the pyrolysis reaction and affecting product yield and purity. Second, the feeding and mixing methods are relatively simple. Most equipment only has a single feed port, which cannot achieve the step-by-step addition or precise proportioning of multi-component materials, and lacks an effective internal disturbance mechanism, resulting in insufficient contact of reactants and a need to improve reaction efficiency. Third, by-products or unreacted substances generated during the reaction are prone to deposit at the bottom of the cylinder, often accompanied by blockage during discharge, and the gas-liquid phase separation is incomplete, affecting the continuous operation of subsequent processes. Fourth, the equipment lacks vacuum or exhaust auxiliary functions, making operation inconvenient when it is necessary to remove non-condensable gases or adjust the reaction pressure, thus limiting the space for optimizing process conditions. Utility Model Content

[0004] The purpose of this invention is to provide a cracking reactor for the production of 3,3-dimethylacrylic acid by acetic acid cracking, which has the advantages of precise temperature control, flexible feeding, good separation effect, and can improve reaction efficiency and product quality, thus solving the problems in the prior art.

[0005] To achieve the above objectives, this utility model provides the following technical solution: A cracking reactor for producing 3,3-dimethylacrylic acid by acetic acid cracking includes a support platform, an insulation cylinder fixed to the upper part of the support platform, a vertical cylinder fixed to the inner wall of the insulation cylinder, two fixing rings fixed to the inner wall of the vertical cylinder, a plurality of second air heating rods fixed to one end of the two fixing rings close to each other, a reaction cylinder fixed to the inner wall of the two fixing rings, a steam input mechanism disposed on the outer peripheral wall of the vertical cylinder for injecting steam into the reaction cylinder, a lifting mechanism disposed on the upper part of the support platform, a lifting column disposed at the output end of the lifting mechanism, a pressure plate fixed to the lower end of the lifting column, a second liquid inlet pipe fixed to the lower end of the pressure plate, a third valve body disposed on the second liquid inlet pipe, a first liquid inlet mechanism disposed at the upper end of the reaction cylinder, a second liquid inlet mechanism disposed on the outer peripheral wall of the reaction cylinder, a first fixing plate fixed to the middle part of the inner wall of the reaction cylinder, a fixing pipe fixed to the lower end of the first fixing plate, a fifth valve body disposed on the fixing pipe, and a separation mechanism fixed to the lower part of the inner wall of the reaction cylinder. A limiting hole is opened through the upper end of the reaction cylinder, and the inner wall of the limiting hole fits against the outer peripheral wall of the lifting column; The insulation cylinder has a hollow structure, and multiple first air heating rods are fixed to the bottom surface of the inner wall of the insulation cylinder. The first fixed plate is equipped with a temperature detection mechanism inside its wall, and the lower end of the reaction cylinder is equipped with a discharge mechanism and a vacuum tube.

[0006] Preferably, the steam input mechanism includes a steam input pipe that is fixed to the outer peripheral wall of the vertical cylinder and a first valve body disposed on the steam input pipe. The outlet end of the steam input pipe passes through the outer peripheral walls of the vertical cylinder and the reaction cylinder and extends to the inner wall of the reaction cylinder.

[0007] It is worth noting that by setting up the aforementioned steam input mechanism, the function of directly injecting steam into the inside of the reaction cylinder is realized. This allows for the rapid and uniform introduction of water vapor into the reaction system, providing the necessary gaseous environment and heat transfer medium for the acetic acid cracking reaction. The outlet of the steam input pipe extends directly to the inner wall of the reaction cylinder, which can prevent the high-temperature steam from condensing in the pipeline and ensure that the steam enters the reaction area directly in gaseous form, thereby improving the thermal energy utilization efficiency. At the same time, the first valve body set on the steam input pipe can precisely control the steam injection flow rate and timing. In conjunction with other liquid inlet mechanisms, the gas phase composition and pressure inside the reaction cylinder can be flexibly adjusted, thereby improving the product yield and purity.

[0008] Preferably, the lifting mechanism includes a bracket fixed to the upper end of the support platform and an electric cylinder fixed to the bracket, wherein the lower end of the output shaft of the electric cylinder is in contact with the upper end of the lifting column.

[0009] It is worth noting that by adopting the above-mentioned lifting mechanism, the lifting column is driven by an electric cylinder to perform vertical reciprocating motion within the limit hole, which enables precise control of the pressure plate position, thereby changing the effective volume of the upper part of the reaction cylinder or applying specific pressure to the material. This lifting mechanism can provide stable and reliable power output, avoid the cumbersome and inaccurate nature of manual operation, and significantly improve the automation level of the equipment.

[0010] Preferably, the first liquid inlet mechanism includes a first liquid inlet pipe that is fixedly connected to the upper end of the reaction cylinder and a second valve body disposed on the first liquid inlet pipe.

[0011] It is worth noting that the first liquid inlet mechanism provides an independent material inlet at the top of the reactor. Its advantage lies in its primary use for introducing low-boiling-point raw materials or raw materials that need to be distributed from the top into the reaction vessel, such as some acetic acid or reaction solvents. The materials added through the first liquid inlet pipe can flow down naturally by gravity, forming a distribution at the top of the reaction vessel. This facilitates countercurrent contact with the rising steam or hot gas from the bottom, preheating the materials and achieving preliminary gas-liquid exchange. The presence of the second valve body allows the operator to independently control the opening, closing, and flow rate of this feed path according to process requirements, enabling time-sharing or coordinated feeding with the second liquid inlet mechanism. This optimizes the mixing ratio and contact sequence of the reactants, helping to improve the conversion rate and selectivity of the pyrolysis reaction.

[0012] Preferably, the second liquid inlet mechanism includes a third liquid inlet pipe that is fixed to the outer peripheral wall of the reaction cylinder and a fourth valve body disposed on the third liquid inlet pipe.

[0013] It is worth noting that the design of the second liquid inlet mechanism, by setting a third liquid inlet pipe on the outer peripheral wall of the reaction cylinder, provides a way for the reactor to introduce materials from the middle or a specific height. Its advantage is that it can realize the directional and layered injection of materials, avoiding excessive mixing or local reaction of multiple materials in the early stage of feeding. For example, catalyst solution or high-boiling-point reactants can be directly added to the reaction zone in the middle of the reaction cylinder through this mechanism, so that they can quickly participate in the cracking reaction and reduce the contact and residence time with the reactor wall. The configuration of the fourth valve body allows the feed to be controlled independently and precisely. In conjunction with the first liquid inlet mechanism and the second liquid inlet pipe, it is possible to construct complex feeding programs to meet the process requirements of multi-component and multi-stage reactions.

[0014] Preferably, the temperature detection mechanism includes a tank, a first temperature sensor, and a second temperature sensor. The tank is formed inside the wall of the first fixed plate. The first temperature sensor is fixed to the top surface of the inner wall of the tank, and the second temperature sensor is fixed to the bottom surface of the inner wall of the tank.

[0015] It is worth noting that this temperature detection mechanism, by setting two temperature sensors, one above the other, within the first fixed plate, achieves precise monitoring of the temperature at different axial heights within the reaction chamber. Its advantage lies in its ability to acquire real-time temperature gradient data between the upper and lower parts of the reaction zone, providing crucial information for judging the progress and uniformity of the pyrolysis reaction. Since the synthesis of 3,3-dimethylacrylic acid is extremely sensitive to temperature, the dual-point detection method effectively avoids measurement deviations caused by a single sensor, promptly detecting localized overheating or insufficient temperature. Embedding the sensors within the grooves of the fixed plate wall protects them from direct material impact and allows for accurate reflection of the true temperature of the reaction system through heat conduction from the fixed plate. This provides precise feedback for adjusting the power of external heating elements (such as the first and second air heating rods), ensuring the reaction remains within the optimal temperature range throughout the entire process.

[0016] Preferably, the separation mechanism includes a second fixed plate fixed to the lower part of the inner wall of the reaction cylinder and a filter hole that extends through the lower end of the second fixed plate.

[0017] It is worth noting that the second fixed disk and the filter holes at its lower end in the separation mechanism constitute a built-in preliminary solid-liquid separation barrier. Its advantage is that it can filter the reaction products in situ after the reaction is completed or during the reaction. When the reaction mixture flows to the bottom of the reaction cylinder under the action of gravity, the second fixed disk can block unreacted solid catalyst, polymers or impurity particles generated during the reaction, while the liquid products flow into the collection area below through the filter holes. This design simplifies the post-processing process, avoids the cumbersome operation of removing the entire reaction mixture for filtration, and reduces the loss and pollution risk during material transfer.

[0018] Preferably, the discharge mechanism includes a drain pipe that is fixedly connected to the lower end of the reaction cylinder and a sixth valve body disposed on the drain pipe.

[0019] It is worth noting that the discharge mechanism, through the combination of the drain pipe and the sixth valve body, provides a controllable and safe discharge channel for the collection of products after the reaction is completed. The sixth valve body can precisely control the start and stop of the discharge and the flow rate, preventing material splashing or leakage and ensuring operational safety. In addition, this design also facilitates a closed connection with downstream storage tanks or refining equipment, enabling continuous product transfer and avoiding prolonged contact between the product and air. This plays a positive role in maintaining the purity of 3,3-dimethylacrylic acid and preventing its oxidative deterioration.

[0020] Preferably, the vacuum tube includes a suction pipe that is fixedly connected to the lower end of the reaction cylinder, a seventh valve body disposed on the suction pipe, and a U-shaped tube fixed to the upper end of the suction pipe. The U-shaped tube is an inverted U-shape, and the suction end of the U-shaped tube faces directly above the drain pipe.

[0021] It is worth noting that the inverted U-shaped tube and its suction end facing directly above the drain pipe can efficiently evacuate the inside of the reaction cylinder before the reaction to remove air or low-boiling-point byproducts generated by the reaction, creating oxygen-free or negative pressure reaction conditions. This is crucial for suppressing oxidative side reactions during acetic acid cracking. The inverted U-shaped tube's structure can prevent liquid splashing or foam rising during the vacuuming process from being directly sucked into the suction line, providing a certain buffering and protection. Its suction end is deliberately facing directly above the drain pipe, which can preferentially extract the gas in that area (i.e., above the product accumulation area), ensuring that the gas phase environment in that area meets the requirements before discharge. It also helps maintain the system pressure balance during discharge, demonstrating the precision and comprehensiveness of the design.

[0022] Compared with the prior art, the beneficial effects of this utility model are as follows: 1. This utility model constructs a multi-layered, surrounding air heating structure by setting up an insulation cylinder, a vertical cylinder, a fixing ring, and multiple first and second air heating rods. When the device is running, the first air heating rods preheat the air inside the insulation cylinder cavity to form an outer insulation environment. At the same time, the second air heating rods, supported by the fixing ring, directly and uniformly radiate heat to the outer wall of the reaction cylinder. This synergistic heating method solves the problem of local overheating and uneven temperature distribution in traditional jacketed heating, achieving axial and circumferential temperature uniformity inside the reaction cylinder. Combined with two temperature sensors set at the top and bottom of the first fixing plate to monitor and provide feedback on the reaction area in real time, it can accurately control the harsh temperature conditions required for the pyrolysis reaction, thereby significantly improving the yield and purity of the product 3,3-dimethylacrylic acid. 2. This utility model achieves flexible multi-point and multi-stage feeding through the combined design of the first liquid inlet mechanism, the second liquid inlet mechanism, the lifting mechanism, and the second liquid inlet pipe on the pressure plate. When it is necessary to introduce raw materials with different boiling points or properties, light components can be added from the top through the first liquid inlet pipe, and catalysts or heavy components can be added from the middle through the third liquid inlet pipe. At the same time, the lifting mechanism drives the lifting column to move the pressure plate down, so that the second liquid inlet pipe extends below the surface of the reaction liquid for deep injection. This time-sharing, layered, and point-sharing feeding method solves the problems of single feeding method and insufficient contact of reactants in existing equipment, avoids excessive mixing of materials in the early stage of feeding, optimizes the mixing ratio and contact sequence of reactants, strengthens the gas-liquid mass transfer process, and effectively improves the conversion rate of the cracking reaction. 3. This utility model forms a built-in separation mechanism by fixing a second fixed disk with filter holes to the lower part of the inner wall of the reaction cylinder. During or after the reaction, when the reaction mixture flows to the bottom under the action of gravity, the second fixed disk can block unreacted solid catalyst, polymerization by-products and other impurities at the top, while the liquid product flows into the collection area below through the filter holes. This design solves the problems of by-products easily depositing at the bottom of the cylinder, easy blockage of the discharge, and incomplete gas-liquid phase separation. It simplifies the post-processing process, reduces the loss during material transfer, ensures the cleanliness of the final 3,3-dimethylacrylic acid solution, and ensures the continuous and stable operation of subsequent processes. 4. This utility model optimizes the gas phase management function of the reactor by setting up a vacuum pipe with an inverted U-shaped tube and pointing the suction end directly above the drain pipe. Before the reaction starts, the seventh valve body is opened to evacuate the inside of the reaction cylinder through the suction pipe. The inverted U-shaped tube can effectively prevent liquid splashing or foam from being sucked into the vacuum pipe, playing a buffering and protective role. This mechanism solves the problems of lack of exhaust auxiliary function, difficulty in removing non-condensable gases or adjusting reaction pressure. It can create an anaerobic or negative pressure optimal environment for acetic acid cracking reaction, suppress the occurrence of oxidation side reactions, and at the same time help maintain system pressure balance after the reaction, creating favorable conditions for material discharge. Attached Figure Description

[0023] Figure 1 The diagram shown is a three-dimensional structural schematic of this utility model; Figure 2 The diagram shown is a three-dimensional cross-sectional view of the present invention. Figure 3 The diagram shown is a three-dimensional cross-sectional view of the first and second liquid inlet mechanisms of this utility model. Figure 4 The diagram shown is a three-dimensional cross-sectional view of the steam input mechanism of this utility model. Figure 5 The diagram shown is a three-dimensional cross-sectional view of the temperature detection mechanism of this utility model. Figure 6 The diagram shown is a three-dimensional cross-sectional view of the separation mechanism of this utility model. Figure 7 The diagram shown is a three-dimensional cross-sectional view of the material discharge mechanism and vacuum tube of this utility model.

[0024] Reference numerals: 1. Support platform; 2. Insulation cylinder; 201. First air heating rod; 3. Vertical cylinder; 4. Fixing ring; 5. Second air heating rod; 6. Reaction cylinder; 7. Steam input pipe; 8. First valve body; 9. Bracket; 10. Electric cylinder; 11. Lifting column; 12. First liquid inlet pipe; 13. Second valve body; 14. Limiting hole; 15. Pressure plate; 16. Second liquid inlet pipe; 17. Third valve body; 18. Third liquid inlet pipe; 19. Fourth valve body; 20. First fixing plate; 21. Fixing pipe; 22. Fifth valve body; 23. Tank; 24. First temperature sensor; 25. Second temperature sensor; 26. Second fixing plate; 27. Filter hole; 28. Drain pipe; 29. ​​Sixth valve body; 30. Suction pipe; 31. Seventh valve body; 32. U-shaped pipe. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0026] To address the problems in existing technologies, such as uneven heating leading to poor temperature control accuracy, limited feeding methods resulting in insufficient mixing, easy product deposition and blockage with incomplete gas-liquid phase separation, and lack of vacuum regulation capabilities, the following technical solution is proposed. Please refer to [link / reference needed]. Figures 1-7 ; A cracking reactor for producing 3,3-dimethylacrylic acid by acetic acid cracking includes a support platform 1, an insulation cylinder 2 fixed to the upper end of the support platform 1, a vertical cylinder 3 fixed to the inner wall of the insulation cylinder 2, two fixing rings 4 fixed to the inner wall of the vertical cylinder 3, a plurality of second air heating rods 5 fixed to one end of the two fixing rings 4, a reaction cylinder 6 fixed to the inner wall of the two fixing rings 4, a steam input mechanism disposed on the outer peripheral wall of the vertical cylinder 3 for injecting steam into the reaction cylinder 6, a lifting mechanism disposed on the upper end of the support platform 1, and a lifting mechanism disposed on the elevator. The structure includes a lifting column 11 at the output end, a pressure plate 15 fixed to the lower end of the lifting column 11, a second liquid inlet pipe 16 fixed to the lower end of the pressure plate 15, a third valve body 17 on the second liquid inlet pipe 16, a first liquid inlet mechanism on the upper end of the reaction cylinder 6, a second liquid inlet mechanism on the outer peripheral wall of the reaction cylinder 6, a first fixed plate 20 fixed to the middle of the inner wall of the reaction cylinder 6, a fixed pipe 21 fixed to the lower end of the first fixed plate 20, a fifth valve body 22 on the fixed pipe 21, and a separation mechanism fixed to the lower part of the inner wall of the reaction cylinder 6. A limiting hole 14 is provided through the upper end of the reaction cylinder 6, and the inner wall of the limiting hole 14 is in contact with the outer peripheral wall of the lifting column 11. The heat insulation cylinder 2 has a hollow structure, and multiple first air heating rods 201 are fixed to the bottom surface of the inner wall of the cavity of the heat insulation cylinder 2. The first fixed plate 20 is equipped with a temperature detection mechanism inside its wall, and the lower end of the reaction cylinder 6 is equipped with a discharge mechanism and a vacuum tube.

[0027] In this embodiment, specifically: the steam input mechanism includes a steam input pipe 7 that is fixed to the outer peripheral wall of the vertical cylinder 3 and a first valve body 8 disposed on the steam input pipe 7. The steam outlet end of the steam input pipe 7 passes through the outer peripheral walls of the vertical cylinder 3 and the reaction cylinder 6 and extends to the inner wall of the reaction cylinder 6.

[0028] In this embodiment, specifically: the lifting mechanism includes a bracket 9 fixed to the upper end of the support platform 1 and an electric cylinder 10 fixed to the bracket 9, with the lower end of the output shaft of the electric cylinder 10 and the upper end of the lifting column 11 in contact.

[0029] In this embodiment, specifically: the first liquid inlet mechanism includes a first liquid inlet pipe 12 that is fixedly connected to the upper end of the reaction cylinder 6 and a second valve body 13 disposed on the first liquid inlet pipe 12.

[0030] In this embodiment, specifically: the second liquid inlet mechanism includes a third liquid inlet pipe 18 that is fixed to the outer peripheral wall of the reaction cylinder 6 and a fourth valve body 19 disposed on the third liquid inlet pipe 18.

[0031] In this embodiment, specifically: the temperature detection mechanism includes a tank 23, a first temperature sensor 24 and a second temperature sensor 25. The tank 23 is provided in the wall of the first fixed plate 20. The first temperature sensor 24 is fixedly connected to the top surface of the inner wall of the tank 23, and the second temperature sensor 25 is fixedly connected to the bottom surface of the inner wall of the tank 23.

[0032] In this embodiment, specifically: the separation mechanism includes a second fixed disk 26 fixed to the lower part of the inner wall of the reaction cylinder 6 and a filter hole 27 that passes through the lower end of the second fixed disk 26.

[0033] In this embodiment, specifically: the discharge mechanism includes a drain pipe 28 that is fixedly connected to the lower end of the reaction cylinder 6 and a sixth valve body 29 disposed on the drain pipe 28.

[0034] In this embodiment, specifically: the vacuum tube includes a vacuum pipe 30 that is fixedly connected to the lower end of the reaction cylinder 6, a seventh valve body 31 that is disposed on the vacuum pipe 30, and a U-shaped tube 32 that is fixed to the upper end of the vacuum pipe 30. The U-shaped tube 32 is an inverted U-shape, and the vacuum end of the U-shaped tube 32 faces directly above the drain pipe 28.

[0035] Working principle: First, the operator injects the initial reaction material into the reaction cylinder 6 through the first liquid inlet pipe 12 and controls the liquid inlet volume through the second valve body 13. At the same time, multiple first air heating rods 201 on the bottom surface of the inner wall of the heat preservation cylinder 2 are turned on to preheat the hollow cavity of the heat preservation cylinder 2. The external part of the reaction cylinder 6 is initially heated by thermal radiation to reduce heat loss. Subsequently, multiple second air heating rods 5, which are fixed to one end of the two fixed rings 4 and close to each other, are activated to directly heat the inside of the reaction cylinder 6, so that the temperature of the reaction system gradually rises to the temperature range required for the cracking reaction. During the heating process, the first temperature sensor 24 and the second temperature sensor 25 in the groove 23 opened in the wall of the first fixed plate 20 monitor the temperature of the upper gas phase region and the lower liquid phase region in the reaction cylinder 6 in real time. The operator adjusts the heating power of the second air heating rod 5 according to the temperature feedback data to ensure that the reaction temperature is uniform and stable. Once the reaction system reaches the set temperature, heat can be added to the reaction cylinder 6 or the reaction atmosphere can be adjusted through the steam input mechanism according to process requirements. That is, the first valve body 8 is opened so that high-temperature steam enters the inner wall of the reaction cylinder 6 through the steam input pipe 7, directly contacting the reactants and promoting the decomposition and activation of acetic acid molecules. If it is necessary to replenish catalyst, additives or other liquid components during the reaction, it can be done through the second liquid inlet mechanism, that is, by opening the fourth valve body 19, so that the material enters the reaction area from the outer peripheral wall of the reaction cylinder 6 through the third liquid inlet pipe 18, so as to achieve precise replenishment at multiple locations and at multiple time periods. At the same time, the operator can start the lifting mechanism, that is, control the electric cylinder 10 on the support 9 to work. The output shaft of the electric cylinder 10 pushes the lifting column 11 to move vertically back and forth along the limiting hole 14. The lifting column 11 drives the pressure plate 15 to move up and down in the reaction cylinder 6, which generates intermittent squeezing and disturbance to the reactants, breaks the possible material agglomeration or liquid surface stratification, promotes effective collision and mixing between reactant molecules, and improves mass transfer efficiency. If it is necessary to remove some material from the liquid phase for detection or transfer during the reaction process, the fifth valve body 22 can be opened to allow the reaction liquid to flow out to the designated container through the fixed pipe 21 at the lower end of the first fixed plate 20. After the pyrolysis reaction is completed, the reaction mixture falls naturally to the lower part of the reaction cylinder 6 under the action of gravity and is initially separated by the separation mechanism. That is, solid impurities or precipitates are trapped above the second fixed plate 26, while liquid products flow into the bottom area of ​​the reaction cylinder 6 through the filter hole 27. At this time, the operator can open the seventh valve body 31 as needed, and perform vacuuming operation on the bottom of the reaction cylinder 6 through the suction pipe 30 and the inverted U-shaped pipe 32. The suction end of the U-shaped pipe 32 faces directly above the drain pipe 28, which can effectively remove non-condensable gases or low-boiling-point by-products deposited in the discharge port area and prevent gas blockage. At the same time, the inverted structure of the U-shaped pipe 32 can prevent liquid materials from being sucked into the vacuum pipeline. After the evacuation is complete, the sixth valve body 29 is opened to allow the liquid product to be discharged from the reaction cylinder 6 through the drain pipe 28, thus completing the discharge operation. Throughout the reaction process, operators can flexibly control the opening and closing status of each valve and the power of each heating element according to process requirements, so as to achieve precise operation of the entire process from feeding, heating, reaction control to discharge, and ensure that the reaction of acetic acid cracking to produce 3,3-dimethylacrylic acid is carried out efficiently and stably.

[0036] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0037] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention.

Claims

1. A cracking reactor for the production of 3,3-dimethylacrylic acid by cracking of acetic acid, characterized in that: The system includes a support platform (1), an insulation cylinder (2) fixed to the upper end of the support platform (1), a vertical cylinder (3) fixed to the inner wall of the insulation cylinder (2), two fixing rings (4) fixed to the inner wall of the vertical cylinder (3), multiple second air heating rods (5) fixed to one end of the two fixing rings (4), a reaction cylinder (6) fixed to the inner wall of the two fixing rings (4), a steam input mechanism for injecting steam into the reaction cylinder (6) on the outer peripheral wall of the vertical cylinder (3), a lifting mechanism on the upper end of the support platform (1), a lifting column (11) on the output end of the lifting mechanism, and a fixed... The pressure plate (15) at the lower end of the lifting column (11), the second liquid inlet pipe (16) fixedly connected to the lower end of the pressure plate (15), the third valve body (17) set on the second liquid inlet pipe (16), the first liquid inlet mechanism set on the upper end of the reaction cylinder (6), the second liquid inlet mechanism set on the outer peripheral wall of the reaction cylinder (6), the first fixed plate (20) fixedly connected to the middle of the inner wall of the reaction cylinder (6), the fixed pipe (21) fixedly connected to the lower end of the first fixed plate (20), the fifth valve body (22) set on the fixed pipe (21), and the separation mechanism fixedly connected to the lower part of the inner wall of the reaction cylinder (6); A limiting hole (14) is opened through the upper end of the reaction cylinder (6), and the inner wall of the limiting hole (14) is in contact with the outer peripheral wall of the lifting column (11); The heat insulation cylinder (2) is a hollow structure, and multiple first air heating rods (201) are fixed to the bottom surface of the inner wall of the heat insulation cylinder (2). The first fixed plate (20) is equipped with a temperature detection mechanism in its wall, and the lower end of the reaction cylinder (6) is equipped with a discharge mechanism and a vacuum tube.

2. The splitting reactor for producing 3,3-dimethyl acrylic acid by splitting acetic acid according to claim 1, characterized in that: The steam input mechanism includes a steam input pipe (7) that is fixed to the outer peripheral wall of the vertical cylinder (3) and a first valve body (8) disposed on the steam input pipe (7). The steam outlet end of the steam input pipe (7) passes through the outer peripheral wall of the vertical cylinder (3) and the reaction cylinder (6) and extends to the inner wall of the reaction cylinder (6).

3. The splitting reactor for producing 3,3-dimethyl acrylic acid by splitting acetic acid according to claim 1, characterized in that: The lifting mechanism includes a bracket (9) fixed to the upper end of the support platform (1) and an electric cylinder (10) fixed to the bracket (9). The lower end of the output shaft of the electric cylinder (10) is attached to the upper end of the lifting column (11).

4. The splitting reactor for producing 3,3-dimethyl acrylic acid by splitting acetic acid according to claim 1, characterized in that: The first liquid inlet mechanism includes a first liquid inlet pipe (12) that is fixed to the upper end of the reaction cylinder (6) and a second valve body (13) disposed on the first liquid inlet pipe (12).

5. The splitting reactor for producing 3,3-dimethyl acrylic acid by splitting acetic acid according to claim 1, characterized in that: The second liquid inlet mechanism includes a third liquid inlet pipe (18) that is fixed to the outer peripheral wall of the reaction cylinder (6) and a fourth valve body (19) disposed on the third liquid inlet pipe (18).

6. The pyrolysis reactor for producing 3,3-dimethacrylic acid by acetic acid pyrolysis according to claim 3, characterized in that: The temperature detection mechanism includes a tank (23), a first temperature sensor (24), and a second temperature sensor (25). The tank (23) is provided in the wall of the first fixed plate (20). The first temperature sensor (24) is fixed to the top surface of the inner wall of the tank (23), and the second temperature sensor (25) is fixed to the bottom surface of the inner wall of the tank (23).

7. The splitting reactor for producing 3,3-dimethyl acrylic acid by splitting acetic acid according to claim 1, characterized in that: The separation mechanism includes a second fixed plate (26) fixed to the lower part of the inner wall of the reaction cylinder (6) and a filter hole (27) that passes through the lower end of the second fixed plate (26).

8. The splitting reactor for producing 3,3-dimethyl acrylic acid by splitting acetic acid according to claim 1, characterized in that: The discharge mechanism includes a drain pipe (28) that is fixed to the lower end of the reaction cylinder (6) and a sixth valve body (29) installed on the drain pipe (28).

9. The splitting reactor for producing 3,3-dimethyl acrylic acid by splitting acetic acid according to claim 1, characterized in that: The vacuum fitting includes a vacuum pipe (30) that is fixed to the lower end of the reaction cylinder (6), a seventh valve body (31) that is set on the vacuum pipe (30), and a U-shaped pipe (32) that is fixed to the upper end of the vacuum pipe (30). The U-shaped pipe (32) is an inverted U-shape, and the vacuum end of the U-shaped pipe (32) faces directly above the drain pipe (28).

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