Multistage reactor

Abstract

The present disclosure relates to the technical field of compound synthesis, and particularly relates to a multi-layer reactor, which comprises: a reactor body, the reactor body has at least two reaction cavities arranged in sequence in the vertical direction, and the last reaction cavity is provided with an overflow structure, the overflow structure is configured to allow the material to overflow into the next layer reaction cavity when the material height in the reaction cavity reaches a preset height, the reactor body is also provided with a feeding port communicated with the uppermost layer reaction cavity and a discharging port communicated with the lowermost layer reaction cavity; a stirring mechanism, the stirring shaft of the stirring mechanism is rotatably sealed through each reaction cavity, and each reaction cavity is provided with stirring blades rotating with the stirring shaft. The reaction cavity is provided with an overflow structure, and the material is allowed to overflow into the next layer reaction cavity only when the material in the upper layer reaction cavity reaches a preset height, which prolongs the residence time of the raw material in each layer reaction cavity and makes the reaction more complete.

Description

Technical Field

[0001] This disclosure relates to the field of compound synthesis technology, and more particularly to a multilayer reactor. Background Technology

[0002] Alkenyl succinic anhydride (ASA) is an important raw material for light industry and fine chemicals, with wide applications in lubricants, waterproofing agents, hardeners, and many other fields. Particularly in the paper industry, alkenyl succinic anhydride (ASA), as a highly efficient reactive sizing agent, can significantly enhance the tensile strength, waterproofing properties, whiteness, opacity, and abrasion resistance of paper, and helps optimize the chemical environment of the papermaking process.

[0003] Currently, the synthesis of alkenyl succinic anhydride (ASA) generally uses batch reactors as the core equipment, which has problems such as low production efficiency, difficulty in controlling process parameters between batches leading to large fluctuations in product quality, and difficulty in controlling reaction residence time leading to incomplete reaction.

[0004] In addition, although there are some continuous reactors on the market, such as microchannel reactors, their structures are complex. Furthermore, the reaction raw materials and products of alkenyl succinic anhydride (ASA) have high viscosity, which can easily cause blockage. The maintenance and cleaning difficulty and cost are far greater than those of batch reactors that can be cleaned in an open manner, which puts forward new requirements for the accuracy of reactor feeding. Utility Model Content

[0005] The purpose of this disclosure is to overcome the shortcomings of the prior art and provide a multi-layer reactor.

[0006] This disclosure provides a multilayer reactor for preparing alkenyl succinic anhydride, the multilayer reactor comprising: The reactor body has at least two reactor chambers arranged sequentially along the vertical direction, and the upper reactor chamber is provided with an overflow structure. The overflow structure is configured to allow the material to overflow into the lower reactor chamber when the material height in the reactor chamber reaches a preset height. The reactor body also has an inlet communicating with the uppermost reactor chamber and an outlet communicating with the lowermost reactor chamber. A stirring mechanism, wherein the stirring shaft of the stirring mechanism is rotatably sealed through each of the reaction chambers, and stirring blades that rotate with the stirring shaft are provided in each of the reaction chambers.

[0007] In one embodiment of this disclosure, the reactor body includes a cylindrical body and a partition that divides the cylindrical body into a plurality of reaction chambers, a liquid surface enclosure formed by extending upward from the partition and an overflow enclosure formed by extending upward from the liquid surface enclosure. The overflow enclosure has an overflow notch, and the overflow structure is formed by the overflow notch and the gaps between the partition, the liquid surface enclosure, the overflow enclosure and the inner wall of the cylindrical body.

[0008] In one embodiment of this disclosure, a flow-guiding surface is further provided on the inner wall of the cylinder, the flow-guiding surface being configured to guide the material flowing out of the gap into the liquid surface enclosure of the next reaction chamber.

[0009] In one embodiment of this disclosure, the vertical cross-sectional shape of the drainage surface includes a straight segment extending horizontally inward from the inner wall of the cylinder and an arc segment toward the next layer of reaction chamber.

[0010] In one embodiment of this disclosure, the central angle corresponding to the arc segment is 90°-180°.

[0011] In one embodiment of this disclosure, the reactor body further includes a product accumulation chamber disposed below the lowest reaction chamber, and the lowest reaction chamber is connected to the discharge port through the product accumulation chamber.

[0012] In one embodiment of this disclosure, the horizontal cross-section of the cylinder and the product stacking cavity is circular.

[0013] In one embodiment of this disclosure, the diameters of the cylinder and the product stacking cavity gradually decrease from top to bottom.

[0014] In one embodiment of this disclosure, the reduction in diameter of the product stacking cavity is greater than the reduction in diameter of the cylinder.

[0015] In one embodiment of this disclosure, a jacket is provided on the outer wall of the reactor body, with a heat transfer oil inlet at the upper end and a heat transfer oil outlet at the lower end. The jacket is configured to provide heat to the reactor body.

[0016] One beneficial effect of the multi-layer reactor disclosed herein is that the reactor body is sequentially arranged with multiple reaction chambers, each equipped with stirring blades. The materials in each reaction chamber are stirred and fully reacted. Furthermore, an overflow structure is incorporated within the reaction chambers, allowing material to overflow into the next reaction chamber only when it reaches a preset height in the upper chamber. This increases the residence time of the raw materials in each reaction chamber, resulting in a more complete and thorough reaction. Moreover, materials are continuously added from the feed inlet at the top of the reactor body, and the product is collected from the discharge outlet at the bottom, achieving a continuous preparation process. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the present disclosure and, together with their description, serve to explain the principles of the present disclosure.

[0018] Figure 1 This is a schematic diagram of the structure of a multilayer reactor provided in one embodiment of the present disclosure; Figure 2 This is a schematic diagram of the overflow structure provided in one embodiment of the present disclosure.

[0019] Figure 1 and Figure 2 The one-to-one correspondence between the component names and the reference numerals in the figures is as follows: 1-Reactor body; 11-Reaction chamber; 12-Baffle; 13-Drainage surface; 14-Product accumulation chamber; 21-Liquid surface enclosure; 22-Overflow enclosure; 23-Overflow notch; 24-Gap; 3-Stirring mechanism; 31-Stirring shaft; 32-Stirring blades; 4-Jacket; 41-Heat transfer oil inlet; 42-Heat transfer oil outlet; 5-Temperature measuring port; 6-Safety valve pressure relief port; 7-Pressure measuring port. Detailed Implementation

[0020] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present disclosure.

[0021] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this disclosure or its application or use.

[0022] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0023] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0024] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0025] In this article, terms such as "up," "down," "front," "back," "left," and "right" are used only to indicate the relative positional relationship between related parts, rather than to define the absolute position of these related parts.

[0026] In this article, "first," "second," etc., are used only to distinguish one another, and not to indicate degree of importance, order, or prerequisite for each other.

[0027] In this document, terms such as “equal” and “same” are not strict mathematical and / or geometric limitations, but also include errors that are understandable to those skilled in the art and permissible in manufacturing or use.

[0028] Existing batch reactors suffer from low production efficiency, difficulty in controlling process parameters between batches leading to large fluctuations in product quality, and difficulty in controlling reaction residence time resulting in incomplete reactions. Existing continuous reactors, on the other hand, have complex structures, and the high viscosity of the reactants and products of alkenyl succinic anhydride (ASA) easily causes clogging. Their maintenance and cleaning are far more difficult and costly than those of open-type cleanable batch reactors. Therefore, this disclosure provides a multi-layer reactor. For ease of understanding, see below for reference. Figure 1 , Figure 2 The specific structure and working principle of the multilayer reactor disclosed herein will be described in detail with reference to the embodiments.

[0029] This disclosure provides a multilayer reactor for preparing alkenyl succinic anhydride. The multilayer reactor includes a reactor body 1 and a stirring mechanism 3. The reactor body 1 has at least two reaction chambers 11 arranged sequentially along the vertical direction, and the upper reaction chamber is provided with an overflow structure. The overflow structure is configured to allow the material to overflow into the lower reaction chamber when the material height in the reaction chamber 11 reaches a preset height. The reactor body 1 also has an inlet communicating with the uppermost reaction chamber and an outlet communicating with the lowermost reaction chamber. The stirring shaft 31 of the stirring mechanism 3 is rotatably sealed through each reaction chamber 11, and stirring blades 32 that rotate with the stirring shaft 31 are provided in each reaction chamber 11.

[0030] Specifically, the reactor body 1 has multiple reaction chambers 11 arranged from top to bottom. The uppermost reaction chamber is connected to the feed inlet, and the lowermost reaction chamber is connected to the discharge outlet. The feed inlet is configured according to the required reaction. Taking the preparation of alkenyl succinic anhydride as an example, the raw materials include C16 and C18 inner olefins and maleic anhydride. The raw materials are added to the reactor and mixed. 2,6-di-tert-butyl-p-cresol is added in stages as an antioxidant to inhibit the oxidation of the materials, and finally alkenyl succinic anhydride is obtained. Therefore, the feed inlets include the inner olefin feed inlet, the maleic anhydride feed inlet, and the antioxidant feed inlet, all of which are located at the top of the reactor body 1. In addition, the multi-layer reactor is also applicable to other microscopic heterogeneous high carbon number reactions, and corresponding feed inlets and discharge outlets need to be set for specific reactions.

[0031] The stirring mechanism 3 includes a stirring shaft 31, stirring blades 32 fixedly connected to the stirring shaft 31, and a driving element for driving the stirring shaft 31 to rotate. The driving element is located on the top of the outer side of the reactor body 1. The stirring shaft 31 passes through each reaction chamber 11, and the passage is sealed to prevent material from flowing into the next reaction chamber from the passage. When the stirring shaft 31 rotates, it drives the stirring blades 32 to stir the material.

[0032] The reaction chamber 11 is equipped with an overflow structure. When the material is added from the feed port to the uppermost reaction chamber, it is mixed and reacted by the stirring of the stirring blades 32. As more and more material is added, the material overflows into the next reaction chamber through the overflow structure until the height of the added material reaches the preset height.

[0033] With this configuration, the reactor body 1 is provided with multiple reaction chambers 11 in sequence, and each reaction chamber 11 is equipped with stirring blades 32. The materials in each reaction chamber 11 are stirred and fully reacted. In addition, the reaction chamber 11 is equipped with an overflow structure. When the material reaches a preset height in the upper reaction chamber, it is allowed to overflow into the next reaction chamber. This increases the residence time of the raw materials in each reaction chamber 11, making the reaction more complete. Furthermore, materials are continuously added from the feed port at the top of the reactor body 1, and the product is collected from the discharge port at the bottom, realizing the continuity of the preparation process.

[0034] In one embodiment, the reactor body 1 includes a cylinder and a partition 12 that divides the cylinder into several reaction chambers 11, as well as a liquid surface enclosure 21 formed by extending upward from the partition 12 and an overflow enclosure 22 formed by extending upward from the liquid surface enclosure 21. The overflow enclosure 22 has an overflow notch 23. The overflow structure is composed of the overflow notch 23 and the gap 24 between the partition 12, the liquid surface enclosure 21, the overflow enclosure 22 and the inner wall of the cylinder.

[0035] Specifically, the baffles 12 are horizontally arranged inside the cylinder, dividing the cylinder into several reaction chambers 11. All baffles 12 are fixed together by columns extending downwards from the top of the reactor. Through holes are provided at the points where the stirring shaft 31 penetrates the baffles 12, and bearings and mechanical seals are installed within these through holes. The baffles 12 extend upwards to form a liquid surface enclosure 21, which is the reaction space for the material. A preset height is set according to the material's residence time, and the height of the liquid surface enclosure 21 is consistent with the preset height. The liquid surface enclosure 21 continues to extend upwards to form an overflow enclosure 22. The overflow enclosure 22 has overflow notches 23 in the horizontal direction, with two overflow notches 23 on opposite sides. After the material reaches the preset height, it flows out from the overflow notches 23. There is also a gap 24 between the baffle 12, the liquid level barrier 21, the overflow barrier 22 and the inner wall of the cylinder. After the material flows out from the overflow gap 23, it enters the next reaction chamber through the gap 24, which increases the residence time of the raw material in each reaction chamber 11 and makes the reaction more complete.

[0036] In another embodiment, the liquid surface barrier 21 extends upward from the edge of the partition 12. Similarly, the overflow barrier 22 extends upward from the liquid surface barrier 21. The horizontal cross-sectional shape of the liquid surface barrier 21 and the overflow barrier 22 is the same as the edge shape of the partition 12. After the material flows out from the overflow gap 23, it will not be blocked by the partition 12 and can fall directly into the next reaction space from the gap 24.

[0037] In one embodiment, a flow guiding surface 13 is also provided on the inner wall of the cylinder, which is configured to guide the material flowing out of the gap 24 into the liquid surface enclosure 21 of the next reaction chamber.

[0038] Specifically, the drainage surface 13 is fixed to the inner wall of the cylinder, and its position corresponds to the area directly below the gap 24 between the baffle 12, the liquid level barrier 21, the overflow barrier 22 and the inner wall of the cylinder. The drainage surface 13 can be a continuous inclined or curved surface that surrounds the inner wall of the cylinder, with its upper edge fixedly connected to the inner wall of the cylinder and its lower edge extending towards the next reaction chamber.

[0039] In the traditional structure without the flow guide surface 13, after the material flows out of the gap 24, it mainly relies on its own gravity to fall downwards in a free-fall state. This falling method is random, and some material may slide directly down the inner wall of the cylinder, forming wall flow, and fail to fully enter the strong mixing zone of the stirring blades 32 in the next layer of reaction chamber, resulting in a shorter residence time for some material and an unsatisfactory mixing effect. By setting the flow guide surface 13, when the material flows out of the gap 24 of the upper layer, it will first hit or flow through the flow guide surface 13. Due to the guiding effect of the flow guide surface 13, the flow direction of the material is forcibly changed. The material no longer falls vertically, but is guided smoothly and precisely along the inclined or curved shape of the guide surface 13 to the effective working area of ​​the stirring blades 32 in the next reaction chamber, that is, within the liquid surface enclosure 21. The guided material then enters the strong stirring zone of the next reaction chamber, ensuring that the material can stay and react fully in the reaction space of this layer. This greatly improves the uniformity and thoroughness of the material reaction in the entire reactor, and further ensures the stability and consistency of the final product quality.

[0040] In one embodiment, the vertical cross-sectional shape of the drainage surface 13 includes a straight segment extending horizontally inward from the inner wall of the cylinder and an arc segment toward the next layer of reaction chamber.

[0041] Specifically, the straight section of the guide surface 13 starts from the inner wall surface of the cylinder and extends horizontally towards the central axis of the stirring shaft 31. It precisely receives all the material flowing out from the upper gap 24. The horizontal surface provides a stable receiving platform for the falling material, avoiding splashing that could occur if the material falls directly onto the inclined surface. Under the influence of gravity, the material flows out of the gap 24 at a relatively high vertical velocity. When the material falls onto the horizontal straight section of the guide surface 13, its flow direction is forcibly changed for the first time, from vertically downward to horizontal radial flow. This process consumes some of the material's kinetic energy, effectively buffering it and preventing it from violently impacting the lower liquid surface.

[0042] The starting end of the arc segment smoothly connects to the inner end of the straight segment, and from this point, its end points towards the next reaction chamber. The material, buffered and converted to horizontal flow by the straight segment, then enters the arc segment. Under the constraint and guidance of the arc segment, the material's flow path changes again, smoothly and gradually transitioning from horizontal to a downward, oblique flow.

[0043] In one embodiment, the central angle corresponding to the arc segment is 90°-180°.

[0044] Specifically, when the central angle corresponding to the arc segment is 90°, the arc segment is in the shape of a quarter circle; when the central angle corresponding to the arc segment is 180°, the arc segment is in the shape of a semicircle. The overall curvature of the drainage surface 13 changes significantly, which can play a precise guiding role.

[0045] In one embodiment, the reactor body 1 further includes a product accumulation chamber 14 disposed below the lowest reaction chamber, and the lowest reaction chamber is connected to the discharge port through the product accumulation chamber 14.

[0046] Specifically, the reactor body 1 consists of a cylindrical body and a product accumulation chamber 14 below the cylindrical body. The cylindrical body includes at least two reaction chambers 11 for carrying out the reaction. A lid is also provided on the top of the cylindrical body. The lid is fixedly connected to the stirring mechanism 3. The stirring shaft 31, baffle 12, liquid level barrier 21 and overflow barrier 22 inside can be removed together through the lid for easy cleaning.

[0047] The product accumulation chamber 14 is simply a cavity that extends downwards from the cylinder. It does not have a stirring mechanism 3. Although the material flowing out from the bottom reaction chamber has been completely reacted in its main body, its reaction degree and temperature may still have extremely slight fluctuations at the microscopic level. The material stays in the product accumulation chamber 14, which makes the material highly homogenized in terms of composition and temperature.

[0048] In one embodiment, the horizontal cross-section of the cylinder and the product stacking cavity 14 is circular.

[0049] Specifically, the horizontal cross-sections of the reactor shell and the product accumulation cavity 14 have a direct impact on the mechanical strength of the reactor body 1 and the reaction process.

[0050] A circular cross-section, when subjected to internal pressure, can evenly distribute stress throughout the entire shell, minimizing stress concentration at sharp corners or edges. With the same wall thickness and material, a circular cross-section can withstand higher internal pressures than any other shape. This provides a fundamental guarantee for the safe and stable operation of the reactor under higher pressures or potentially fluctuating conditions.

[0051] Unlike cross-sections with corners, the circular cross-section ensures a smooth and continuous interior of the cylinder and product accumulation chamber 14, eliminating "dead zones" for fluid flow. This is crucial for reaction systems like alkenyl succinic anhydride, which may generate gels or byproducts, effectively preventing material retention and accumulation in corners, thus significantly reducing the risk of reactor blockage due to scaling. Furthermore, the circular cross-section of the cylinder and product accumulation chamber 14 results in a more symmetrical and uniform radial velocity distribution. This ensures consistent residence time for all materials, avoiding over-reaction in some areas while incomplete reaction in others, ultimately significantly improving product selectivity and quality uniformity.

[0052] Of all cross-sectional shapes, the circle offers the smallest surface area for a given volume. However, in tubular reactors, a more critical metric is the flow resistance per unit heat transfer area. The circular cross-section allows the fluid to uniformly scour the entire heat transfer wall, and combined with its excellent flow characteristics, enables efficient and uniform heat transfer between the tube wall and the fluid. This is crucial for temperature control in typically exothermic reactions such as the synthesis of alkenyl succinic anhydride, effectively preventing side reactions caused by localized overheating.

[0053] The circular cross-section cylinder and product accumulation chamber 14 have smooth, dead-angle-free internal surfaces, making it easier to thoroughly clean the reactor during regular maintenance.

[0054] In one embodiment, the diameters of the cylinder and the product stacking cavity 14 gradually decrease from top to bottom.

[0055] Specifically, the alkenyl succinic anhydride molecule is mainly composed of a long-chain olefin hydrophobic framework and polar succinic anhydride groups. Due to the extremely strong intermolecular forces, the alkenyl succinic anhydride exhibits high viscosity. Both the cylinder and the product accumulation chamber 14 are inverted frustum shapes. In multi-layer continuous reactions, the overall flow direction of the material is from top to bottom. The inverted frustum structure matches this direction. Compared to a straight cylindrical structure, the inclined walls provide a smoother, more abrupt channel for the downward-flowing material, effectively reducing material adhesion and retention on the walls. When the final product flows into the bottommost product accumulation chamber 14 after the reaction, the inverted frustum bottom structure forms a natural funnel shape, guiding the material to converge unimpeded towards the central outlet, ensuring thorough discharge and reducing residue. This is particularly suitable for high-viscosity material systems or those containing solids.

[0056] When the stirring device is working, the fluid thrown against the reactor wall by the stirring blades 32 falls along the inclined wall, promoting material exchange between different height layers and effectively alleviating the problem of material stratification in the vertical direction. In addition, the inverted frustum-shaped structure makes the outer jacket 4 wall of the reactor conducive to the flow and distribution of the heat medium, which may reduce dead zones and improve the overall heat transfer coefficient.

[0057] In one embodiment, the reduction in diameter of the product stacking cavity 14 is greater than the reduction in diameter of the cylinder.

[0058] Specifically, the diameter of the upper cylinder decreases only slightly, meaning the inner wall of the cylinder has a gentle slope, ensuring that each reaction chamber 11 has a reasonable volume. At the same time, the relatively gentle wall surface allows the material thrown out by the agitator to come into full contact with it and slide down at an appropriate speed under the action of gravity, which promotes radial mixing and ensures sufficient reaction residence time.

[0059] The lower product accumulation chamber 14 has a significantly reduced diameter, meaning its inner wall is steeply sloped, forming a funnel structure. This provides a strong driving force for material collection, guiding the material to flow extremely quickly and smoothly towards the central discharge port. This is crucial for high-viscosity materials, effectively preventing material accumulation and blockage in the bottom corners. During continuous discharge, the steep wall greatly reduces the low-speed flow zone or dead zone near the wall, ensuring that all material participates in orderly flow and renewal, avoiding long-term retention of some material.

[0060] In one embodiment, a jacket 4 is provided on the outer wall of the reactor body 1. A heat transfer oil inlet 41 is provided at the upper end of the jacket 4, and a heat transfer oil outlet 42 is provided at the lower end. The jacket 4 is configured to provide heat to the reactor body 1.

[0061] Specifically, the jacket 4 is a closed cavity structure that wraps around the outside of the reactor body 1. The jacket 4 is connected to the outer wall of the reactor body 1 by welding or other methods, ensuring a tight bond between the two to form a stable pressure-bearing structure and enabling efficient heat conduction. A heat transfer oil inlet 41 is provided at the upper part of the jacket 4, and a heat transfer oil outlet 42 is provided at its lower part. This high-level oil inlet and low-level oil outlet arrangement constitutes a top-down heating system.

[0062] High-temperature heat transfer oil is pumped in through the heat transfer oil inlet 41 located at the top of the jacket 4. Under the influence of gravity and its own momentum, it naturally flows downward along the outer wall of the reactor body 1, evenly filling the entire cavity of the jacket 4. Finally, it is collected from the heat transfer oil outlet 42 located at the bottom and returned to the external heating system for recirculation heating. This provides stable heat to all reaction chambers 11, ensuring that each reaction can proceed within the preset optimal temperature range.

[0063] A temperature measuring port 5 is also provided at the top of the reactor body 1, and the temperature measuring pipe extends all the way to the bottom reaction chamber. The temperature of each reaction chamber 11 can be precisely controlled to ensure that the chemical reaction proceeds along the predetermined path, suppress side reactions, and improve product yield and purity.

[0064] The reactor body 1 is also equipped with a pressure measuring port 7 and a safety valve pressure relief port 6, which are used to detect the pressure in the reaction chamber 11 and release the pressure when it is too high, thus ensuring the safety of the reaction process.

[0065] The multi-layer reactor disclosed herein can be directly modified from a traditional batch reactor, greatly reducing costs. It also has the advantage of an openable top cover for easy internal cleaning. Meanwhile, materials are continuously added from the feed inlet at the top of the reactor body 1, and the product is collected from the discharge outlet at the bottom, ensuring the continuity of the preparation process.

[0066] In one embodiment, four reaction spaces are provided, and the reaction conditions are shown in Table 1, while the equipment parameters are shown in Table 2.

[0067] Table 1:

[0068] Table 2:

[0069] Furthermore, to facilitate better understanding, the preparation process of alkenyl succinic anhydride using the multilayer reactor disclosed herein will be explained in detail below in conjunction with practical application scenarios.

[0070] 1. Equipment preheating and nitrogen purging: Nitrogen gas is introduced to purge the air in the multi-layer reactor, ensuring the oxygen content is ≤0.5%. Heat transfer oil is injected into jacket 4, and the heat exchange system of jacket 4 is turned on to preheat the reaction space to 100℃.

[0071] 2. Raw material feeding and initial mixing: The inner olefin is pumped into the first reaction chamber through a metering pump. Maleic anhydride (molten state, temperature 80-90℃) is simultaneously pumped into the first reaction chamber through another metering pump. At the same time, antioxidant (mass of 0.05%-0.1% of the total mass of inner olefin and maleic anhydride) is added and stirring is started (500r / min). The temperature is then raised to 200-230℃ to start the reaction.

[0072] 3. Multi-layer continuous reaction: When the material reaches a preset height in the first reaction chamber, it falls onto the guide surface 13 through the overflow notch 23 and gap 24. Then, guided by the guide surface 13, it enters the second reaction chamber. The first layer is continuously fed to carry out the reaction, and so on until the product flows out from the bottom. The temperature fluctuation of each layer is observed through multiple thermometers.

[0073] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, and are not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein. The scope of this disclosure is defined by the appended claims.

Claims

1. A multilayer reactor for preparing alkenyl succinic anhydride, characterized in that, The multilayer reactor includes: The reactor body (1) has at least two reaction chambers (11) arranged in sequence along the vertical direction, and the upper reaction chamber is provided with an overflow structure. The overflow structure is configured to allow the material to overflow into the lower reaction chamber after the material height in the reaction chamber (11) reaches a preset height. The reactor body (1) is also provided with an inlet connected to the uppermost reaction chamber and an outlet connected to the lowermost reaction chamber. The stirring mechanism (3) has a stirring shaft (31) that is rotatably sealed through each of the reaction chambers (11), and each of the reaction chambers (11) is provided with stirring blades (32) that rotate with the stirring shaft (31).

2. The multi-layer reactor according to claim 1, characterized in that, The reactor body (1) includes a cylinder and a partition (12) that divides the cylinder into several reaction chambers (11), as well as a liquid surface enclosure (21) extending upward from the partition (12) and an overflow enclosure (22) extending upward from the liquid surface enclosure (21). The overflow enclosure (22) has an overflow notch (23). The overflow structure is formed by the overflow notch (23) and the gap (24) between the partition (12), the liquid surface enclosure (21), the overflow enclosure (22) and the inner wall of the cylinder.

3. The multi-layer reactor according to claim 2, characterized in that, The inner wall of the cylinder is also provided with a flow guiding surface (13), which is configured to guide the material flowing out of the gap (24) into the liquid surface enclosure (21) of the next reaction chamber.

4. The multi-layer reactor according to claim 3, characterized in that, The vertical cross-sectional shape of the drainage surface (13) includes a straight line segment extending horizontally inward from the inner wall of the cylinder and an arc segment toward the next layer of reaction chamber.

5. The multi-layer reactor according to claim 4, characterized in that, The central angle corresponding to the arc segment is 90°-180°.

6. The multi-layer reactor according to claim 4, characterized in that, The reactor body (1) also includes a product accumulation chamber (14) located below the lowest reaction chamber, and the lowest reaction chamber is connected to the discharge port through the product accumulation chamber (14).

7. The multi-layer reactor according to claim 6, characterized in that, The horizontal cross-section of the cylinder and the product stacking cavity (14) is circular.

8. The multi-layer reactor according to claim 7, characterized in that, The diameters of the cylinder and the product stacking cavity (14) gradually decrease from top to bottom.

9. The multilayer reactor according to claim 8, characterized in that, The reduction in diameter of the product stacking cavity (14) is greater than the reduction in diameter of the cylinder.

10. The multi-layer reactor according to any one of claims 1-9, characterized in that, The outer wall of the reactor body (1) is provided with a jacket (4), the upper end of the jacket (4) is provided with a heat transfer oil inlet (41), and the lower end is provided with a heat transfer oil outlet (42). The jacket (4) is configured to provide heat to the reactor body (1).

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