Continuous flow stirring reinforced tubular reactor for nitration reaction

Abstract

The invention discloses a continuous flow stirring reinforced tubular reactor for nitration reaction, and belongs to the technical field of chemical reaction devices. The reactor comprises a reactor body and a jacket arranged on the outer side of the reactor body, and a heat exchange space is formed between the jacket and the reactor body; a group of flow separation plates are arranged in the reactor body, the interior of the reactor body is divided into a plurality of stirring layers by the group of flow separation plates, and a rotatable stirring paddle is arranged in each stirring layer; the reactor body comprises an upper body and a lower body which are connected with each other, the lower body is provided with a material inlet, and the upper body is provided with a material outlet and a group of horizontal branch pipes for measuring the internal temperature of the reactor body in real time. The reactor disclosed by the invention has a relatively large specific surface area, and can effectively overcome the defects of short retention time, poor material mixing and serious backmixing of a traditional tubular reactor; the liquid-liquid chemical reactor is good in fluid mechanical property and high in mixing and mass transfer efficiency, and can be widely applied to various gas-liquid or liquid-liquid chemical reaction processes.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical reaction devices, and particularly relates to a continuous flow stirring enhanced tubular reactor for nitration reaction. Background Art

[0002] Nitration reaction is an important type of reaction in organic synthesis and is widely used in industrial fields such as pharmaceuticals, dyes, pesticides, and explosives. This reaction usually involves introducing a nitro group into an organic molecule, and due to its exothermic nature, special requirements are imposed on the design of the reactor. Traditional nitration reactors are mostly batch stirred tank reactors. Although this type of reactor has a simple structure, there are some problems that are difficult to overcome during the nitration reaction. First of all, the nitration reaction is a highly exothermic process. If the reaction heat cannot be removed in time, the reaction temperature will rise sharply, which may trigger side reactions or even safety accidents. Secondly, the thermal stress and corrosive substances generated during the nitration reaction are likely to form scale on the inner wall of the reactor, which not only affects the heat exchange efficiency of the reactor but also increases the difficulty of cleaning and maintenance. In addition, there is a serious backmixing phenomenon in the traditional batch reactor during the nitration reaction, which leads to uneven mixing of reactants and products and affects the selectivity and conversion rate of the reaction. To solve the above problems, continuous flow reactors are gradually adopted in industry. Through the continuous flow of materials, continuous flow reactors can achieve more precise temperature control and better mixing effects, thereby improving the safety and efficiency of the reaction. However, existing continuous flow reactors still have some deficiencies when dealing with nitration reactions. For example, some reactors have insufficient heat exchange and mixing performance and cannot meet the strict requirements for temperature control in nitration reactions; although some other reactors can achieve good heat exchange and mixing, their structures are complex and not easy to clean and maintain.

[0003] Therefore, developing a new type of continuous flow stirring enhanced tubular reactor to overcome the defects of the existing technology and improve the safety, efficiency, and maintainability of nitration reactions has important industrial application value and broad market prospects. Summary of the Invention

[0004] Aiming at the above problems existing in the prior art, the purpose of the present invention is to provide a continuous flow stirring enhanced tubular reactor for nitration reaction, which overcomes the problems of insufficient heat exchange and mixing performance, serious backmixing phenomenon, easy occurrence of scale formation on reaction materials, and inconvenience in cleaning and repairing the inside of the reactor.

[0005] The present invention provides the following technical solution: a continuous flow stirring intensified tubular reactor for nitration reaction, characterized in that it comprises a reactor body and a jacket arranged on the outside of the reactor body, a heat exchange space is formed between the jacket and the reactor body; a group of flow partitions are arranged in the reactor body, the group of flow partitions divides the interior of the reactor body into a plurality of stirring layers, each stirring layer is provided with a rotatable stirring paddle; the reactor body comprises an upper body and a lower body connected to each other, the lower body is provided with a material inlet, the upper body is provided with a material outlet and a group of horizontal branch pipes for real-time measurement of the internal temperature of the reactor body.

[0006] Furthermore, a support rod is fixed inside the reactor body, and a group of flow partitions are arranged on the support rod at intervals along the height direction of the reactor body.

[0007] Furthermore, a rotatable stirring rod is arranged in the reactor body, a group of stirring paddles are fixedly arranged on the stirring rod, and one end of the stirring rod is connected to a motor.

[0008] Furthermore, a gap is left between the flow partition and the inner wall of the reactor body, and a group of holes are evenly opened on the flow partition.

[0009] Furthermore, the upper body and the lower body are connected via a flange structure, a sealing gasket is provided between the flange structure and the upper and lower bodies, a bearing is provided at the flange structure, and the other end of the stirring rod is connected to the bearing.

[0010] Furthermore, the horizontal branch pipe is fixed on the side wall of the reactor body, the fixed end of the horizontal branch pipe is communicated with the interior of the reactor body, and the other end is connected to a thermocouple sensor.

[0011] Furthermore, the jacket heat exchanger is welded on the outer side wall of the reactor body, cooling liquid / heating liquid is introduced into the heat exchange space, and the jacket heat exchanger is provided with a jacket water inlet and outlet.

[0012] Furthermore, the material inlet is located at the bottom or side wall of the lower body, and the material outlet is located on the side wall of the upper body. The flow field and the mixed mass transfer process in the reactor are adjusted by controlling the inlet and outlet flow rates of the materials.

[0013] By adopting the above technology, compared with the prior art, the beneficial effects of the present invention are as follows:

[0014] 1) The reactor of the present invention has a large specific surface area, which can effectively solve the defects of short residence time, poor material mixing and serious backmixing of traditional tubular reactors; it has good fluid mechanics performance, high mixing and mass transfer efficiency, and can be widely used in various gas-liquid or liquid-liquid chemical reaction processes;

[0015] 2) Anti-backmixing design: The present invention adopts the combination of "multi-layer stirring paddles + porous baffle plates" to divide the reactor into multiple independent stirring layers, and balances anti-backmixing and flow efficiency through the gap between the baffle plate and the inner wall, significantly improving the mixing uniformity.

[0016] 3) Modular and easy-to-maintain structure: The reactor body of the present invention is connected by upper and lower split flanges, and is equipped with detachable support rods and baffle plates to achieve rapid disassembly and assembly and thorough cleaning, solving the pain point of difficult maintenance of scale accumulation in traditional reactors.

[0017] 4) Precise dynamic temperature control system: The present invention is embedded with multi-point temperature measurement branch pipes to monitor the temperature in real time, and an external jacket heat exchanger is used to flexibly adjust the cold and hot media, which can ensure the high efficiency and safety of the nitrification reaction.

[0018] 5) Flexible adjustment of fluid parameters: In the present invention, the distance between baffle plates, the pore diameter and the stirring speed can all be optimized and adjusted to meet the requirements of different reaction types (gas-liquid / liquid-liquid), and strengthen mass transfer and reaction efficiency.

[0019] 6) Guarantee of mechanical stability: In the present invention, the stirring rod is fixed by bearings and combined with the gasket design to prevent the axis from shifting or the material from leaking during high-speed operation, taking into account durability and operation safety. Description of the Drawings

[0020] Figure 1 is the overall structural schematic diagram of the present invention;

[0021] Figure 2 is the schematic diagram after the explosion of the present invention;

[0022] Figure 3 is the internal structural schematic diagram of the present invention;

[0023] Figure 4 is the connection structural schematic diagram of the shaft and the blade of the present invention;

[0024] Figure 5 is the connection structural schematic diagram of the baffle plate and the support rod of the present invention;

[0025] Figure 6 is the structural schematic diagram of the connecting piece of the present invention;

[0026] Figure 7 is the structural schematic diagram of the baffle plate of the present invention. Detailed Embodiments

[0027] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings of the specification and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0028] In contrast, the present invention encompasses any substitutions, modifications, equivalent methods, and solutions that are defined by the claims and fall within the spirit and scope of the present invention. Further, in order to enable the public to better understand the present invention, some specific details are described in detail in the following detailed description of the present invention. Those skilled in the art can fully understand the present invention without the description of these details.

[0029] Reference Figures 1-7 , a continuous flow stirred intensifying tubular reactor, comprising a reactor body, a jacket is arranged outside the reactor body, the reactor body includes an upper body 2 and a lower body 4, and the upper and lower bodies are connected by a flange structure.

[0030] Specifically, the jacket is a shell structure, which is welded on the outer wall of the upper body 2 to form a relatively closed heat exchange space, and a jacket water inlet 13 and a jacket water outlet 7 are provided on the side thereof. The heat exchange medium can flow stably and efficiently in this space. When the reaction process requires increasing the temperature of the materials in the reactor, a high-temperature heat exchange medium, such as hot water or hot oil preheated to a specific temperature, can be introduced into the heat exchange space. Through the heat conduction effect, the heat is evenly transferred to the internal materials through the wall surface of the reactor body, promoting the temperature increase of the materials to meet the corresponding reaction conditions; conversely, if the temperature of the materials is too high during the reaction process and needs to be cooled and regulated, a low-temperature cooling medium, such as circulating cold water, is introduced into the heat exchange space to quickly remove the excess heat in the reactor and accurately realize the cooling operation of the materials, ensuring that the reaction is always in the ideal temperature range.

[0031] Specifically, the flange structure includes flanges provided at the ends of the upper body 2 and the lower body 4 and a connecting member 3 located between the two flanges. The two flanges and the connecting member 3 are fixedly connected by fasteners, and a bearing 1 is provided in the middle of the connecting member 3. Sealing gaskets are provided between the connecting member 3 and the upper body 2 and the lower body 4, which can effectively prevent the reaction materials from leaking from the connection part and also prevent external impurities from invading the interior of the reactor.

[0032] Specifically, a first material inlet 8, a second material inlet 14, a bottom outlet 9, and a knob switch 5 for controlling the opening and closing of the bottom outlet 9 are provided on the lower body 4 of the reactor body.

[0033] Specifically, a material outlet 6, a first horizontal branch pipe 10, a second horizontal branch pipe 11, and a third horizontal branch pipe 12 are provided on the upper body 2 of the reactor body. One end of the three horizontal branch pipes is communicated with the inside of the reactor body, and the other end is connected with a thermocouple sensor, serving as a measurement point for real-time temperature measurement, and feeding back the data to the control system in real time to adjust the temperature in a timely manner according to the reaction process requirements, ensuring that the reaction always proceeds orderly within the most suitable temperature range.

[0034] A bearing 1 is also provided on the end cover of the upper body 2.

[0035] Specifically, a support rod 17 is detachably and fixedly installed inside the reactor body. The support rod 17 is made of a high-strength material with a certain corrosion resistance to ensure its stable operation in the complex working environment of the reactor. Three baffle plates 18 are arranged at intervals along the height direction on the two support rods 17, dividing the internal space of the reactor body into multiple stirring layers. In order to avoid unnecessary losses caused by contact friction between the baffle plate and the inner wall of the reactor, and at the same time to ensure the smooth circulation of materials in the reactor, a small gap of 1 mm is reserved between the baffle plate and the inner wall of the reactor.

[0036] Specifically, a stirring rod 16 is arranged inside the reactor body. The stirring rod 16 is connected to the upper and lower bearings 1. By using the arranged bearings 1, the stirring rod 16 can always maintain a stable axial position during high-speed rotation, preventing skewing. Ensure the uniformity and sufficiency of material stirring; the upper end of the stirring rod 16 is connected to a motor, and four stirring paddles 15 are arranged on the stirring rod 16. Each stirring paddle 15 is placed in the corresponding stirring layer; the reaction rate can be increased by setting the type of the stirring paddle 15 and the number of stirring blades.

[0037] The working process of the present invention is as follows: Turn on the motor, control the flow rate of the reactant inlet through the peristaltic pump, and introduce the reactants into the reactor body from the two material inlets. Continuously introduce water at an appropriate temperature into the jacket. During the stirring process, the flow mixing of the materials is realized. It can be known whether the reaction reaches a steady state according to the temperature change monitored by the thermocouple sensor. After reaching stability, measure the product concentration at the outlet.

[0038] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A continuous flow stirred intensified tubular reactor for nitration reaction, characterized in that, The invention comprises a reactor body and a jacket arranged outside the reactor body, wherein a heat exchange space is formed between the jacket and the reactor body; a group of flow partitions (18) are arranged inside the reactor body, and the group of flow partitions (18) divide the interior of the reactor body into a plurality of stirring layers, and a rotatable stirring paddle (15) is arranged in each stirring layer; the reactor body comprises an upper body (2) and a lower body (4) connected to each other, wherein the lower body (4) is provided with a material inlet, and the upper body (2) is provided with a material outlet and a group of horizontal branch pipes for real-time measurement of the internal temperature of the reactor body.

2. The continuous flow stirred intensified tubular reactor for nitration reaction according to claim 1, wherein A support rod (17) is fixed inside the reactor body, and a group of flow partitions (18) are arranged on the support rod (17) at intervals along the height direction of the reactor body.

3. The continuous flow stirring enhanced tubular reactor for nitration reaction according to claim 2, characterized in that, A rotatable stirring rod (16) is arranged in the reactor body, a group of stirring paddles (15) are fixedly arranged on the stirring rod (16), and one end of the stirring rod (16) is connected to a motor.

4. The continuous flow stirred intensification tubular reactor for nitration reaction according to claim 3, characterized in that A gap is left between the flow partition (18) and the inner wall of the reactor body, and a group of holes are evenly opened on the flow partition (18).

5. A continuous flow stirred intensified tubular reactor for nitration reaction according to claim 1, characterized in that, The upper body (2) and the lower body (4) are connected via a flange structure. A sealing gasket is provided between the flange structure and the upper and lower bodies. A bearing (1) is provided at the flange structure. The other end of the stirring rod (16) is connected to the bearing (1).

6. The continuous flow stirred intensified tubular reactor for nitration reaction according to claim 1, wherein The horizontal branch pipe is fixed on the side wall of the reactor body, the fixed end of the horizontal branch pipe is communicated with the interior of the reactor body, and the other end is connected with a thermocouple sensor.

7. A continuous flow stirred intensified tubular reactor for nitration reaction according to claim 1, characterized in that, The jacket heat exchanger is welded on the outer side wall of the reactor body, cooling liquid / heating liquid is introduced into the heat exchange space, and the jacket heat exchanger is provided with a jacket water inlet and outlet.

8. A continuous flow stirred intensified tubular reactor for nitration reaction according to claim 1, characterized in that, The material inlet is located at the bottom or side wall of the lower body (4), and the material outlet is located on the side wall of the upper body (2). The flow field and the mixing mass transfer process in the reactor are regulated by controlling the inlet and outlet flow rates of the materials.

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