Multi-section temperature control continuous coupling reaction device and process

Abstract

The application relates to a multi-section temperature control continuous coupling reaction device and process, the continuous coupling reaction device comprising a high-shear stirrer, a heat exchange coil, a multi-layer stirrer, a wall scraping blade, a vertical baffle, a horizontal partition, and a temperature control jacket. The diazo liquid and the esterification liquid first enter the area where the high-shear stirrer is located, the reaction temperature is controlled at 0-5 DEG C, the coupling reaction slurry enters the multi-layer stirring area from the high-shear stirrer area upwards, and the multi-section temperature control jacket is used to control the reaction temperature of the multi-layer stirring area from the bottom to the top at 10-15 DEG C and 20-25 DEG C in sequence. The application realizes the rapid mixing and reaction of coupling reaction raw materials through the high-shear stirrer, then the multi-layer stirring reaction area is controlled in sections, and the effect of realizing the continuous and efficient coupling reaction is achieved.

Description

Technical Field

[0001] This application relates to the field of equipment for synthesizing intermediates of fine chemical dyes, and in particular to a multi-stage temperature-controlled continuous coupled reaction device and process. Background Technology

[0002] Azo dyes are a major category of organic dyes, accounting for half of the total production capacity of organic dyes. The production of azo dyes involves two chemical reaction processes: diazotization and coupling. The coupling reaction is rapid and exothermic. Furthermore, the aromatic amine diazonium salt added during coupling contains a large amount of concentrated sulfuric acid, and the mixing of materials also generates an acid dilution heat effect. Conventional coupling reactions require the addition of large amounts of ice water for cooling. Because the resulting dye is insoluble in water and the coupling reaction temperature is relatively low, the coupling reaction solution is a high-viscosity slurry.

[0003] Currently, industrial coupling reactions are generally carried out in batches using batch reactors. These reactors are large, and traditional paddle stirring methods result in poor mass and heat transfer. This can easily lead to localized overheating of the reaction solution or excessively high concentrations of the diazo component. Diazo salts are unstable and easily decompose in water and coupling components, ultimately affecting product quality and yield. Therefore, batch coupling reaction processes suffer from high energy consumption and low production capacity, necessitating the development of continuous coupling reaction technology for azo dyes to achieve energy conservation, emission reduction, and improved product quality in azo dye production.

[0004] Patent CN102796394A discloses a method for continuous dye coupling and energy utilization, wherein the coupling device adopts a continuous batch reactor, and the reaction temperature of each batch is controlled at 0~5℃. The reaction process utilizes heat exchange between the coupling liquid and washing water to recover the system's cooling capacity. Patent CN105348847A argues that the method of completely mixing the diazo liquid and coupling liquid in patent CN102796394A has drawbacks. Complete mixing of the diazo liquid and coupling liquid generates a large amount of heat, easily leading to untimely temperature control and affecting dye quality. Patent CN105348847A disperses the diazo liquid and continuously feeds it into several series-connected loop reactors for coupling, controlling the reaction temperature of each batch at 0~2℃ to achieve effective temperature control and improve product quality. Patents CN102796394A and CN105348847A employ multi-stage batch reactors or loop reactors for continuous coupling, with the multi-stage reactors overflowing into the next reaction stage. Because the low-temperature coupling reaction solution is a high-viscosity slurry, the overflow of materials between reactors can easily cause blockages in the pipes, affecting the stability of the continuous coupling process.

[0005] Patent CN107961755A discloses an apparatus and method for the coupling reaction of azo dyes. The apparatus uses a pump to pump coupling components and diazo components in a specific ratio, which are then transported to a liquid-liquid jet reactor after heat exchange via a heat exchanger. After thorough mixing and reaction, the mixture enters a tower-type coupling reactor for further reaction, with the reaction temperature controlled between 0 and 10°C. The reacted material is then heated to crystallize and subsequently filtered. This patent enhances the coupling reaction through a liquid-liquid jet mixing reactor; however, the small diameter of the liquid-liquid nozzle channel in the jet reactor makes it easy for the diazo reaction slurry to clog the jet channel. Furthermore, the tower-type reactor lacks a stirring device, leading to the deposition of solid slurry in the coupling liquid, which affects mass and heat transfer in the reaction.

[0006] Patent CN101870824A discloses a method for preparing azo dyes using a hypergravity reactor, comprising a diazotization reaction and a coupling reaction. The method is characterized by carrying out the diazotization, coupling reaction, or both of aromatic or heteroaromatic amines within a hypergravity reactor. While this method initially achieves continuous diazotization, it requires high precision in equipment manufacturing, and scaling up from laboratory to industrial levels is quite complex.

[0007] Patents CN1398282A and CN102847455A disclose microchannel continuous coupling reactors, utilizing microchannel structures to promote mixing and heat transfer during the coupling process. While tubular or microchannel reactors are typically the first-line equipment for continuous production, the high viscosity of the feed solution generated in the low-temperature coupling reaction of dyes easily leads to blockage within the tubular or microchannel reactor, severely hindering the mixing between the diazo component and the coupling component, making them unsuitable for large-scale production. Furthermore, the low temperature results in a long coupling reaction time, requiring very long tubular reactor pipes, which is difficult to implement industrially.

[0008] Patent CN113634216A discloses a method for the continuous diazotization and coupling production of water-soluble azo dyes using a tubular reactor. The patent discloses a tubular reactor with multiple micro-stirring blades distributed axially, completing the diazotization and coupling reactions within the same reactor. At room temperature, the material solution participating in the diazotization reaction enters from the bottom of the tubular reactor. After the diazo solution is confirmed to be completely reacted at a sampling port within the tubular reactor, the coupling component solution is introduced downstream. The coupling component encounters the diazo component and undergoes a coupling reaction under the action of the micro-stirring blades, generating water-soluble azo dye, which eventually overflows from the top. Although the patent promotes the flow of the reaction solution by using micro-stirring blades in the tubular reactor, the micro-stirring blades have limited ability to improve the uniform mixing of the material, especially the micro-mixing, during operation, and the blades can cause backmixing, affecting the product properties. Furthermore, this device is only suitable for water-soluble azo dyes; in non-water-soluble slurry azo dye systems, the micro-stirring cannot promote mixing. Furthermore, the device cannot assess the location where the reaction ends during its design, thus requiring multiple sampling points and feed inlets to be set on the tubular reactor, increasing the complexity of equipment manufacturing.

[0009] Analysis of existing data shows that traditional batch stirred tank reactors struggle to achieve uniform mixing in heterogeneous solid-liquid systems, are prone to side reactions, and suffer from long reaction times and low production efficiency. Existing patents disclose continuous coupling processes where the coupling reaction is maintained at a consistently low temperature, further increasing the viscosity of the coupling slurry, affecting mass and heat transfer efficiency, and causing pipe blockages, thus hindering continuous production. Therefore, there is an urgent need to develop highly versatile continuous coupling process equipment to solve the synthesis problems of azo dyes, especially for high-viscosity slurry coupling reaction systems.

[0010] In view of the continuous coupling reaction process of azo dyes, this application provides a multi-stage temperature-controlled continuous coupling reaction device to improve the mass and heat transfer performance of the continuous coupling reaction process and improve the fluidity of the coupling liquid. Summary of the Invention

[0011] In order to improve the technical problems in the prior art, this application provides a multi-stage temperature-controlled continuous coupling reaction device and process.

[0012] The multi-segment temperature-controlled continuous coupling reaction device provided in this application adopts the following technical solution: In a first aspect, a multi-stage temperature-controlled continuous coupling reaction device includes a continuous coupling device body, a high-shear stirrer, a heat exchange coil, a multi-layer stirring mechanism, a wall scraper blade, a vertical baffle, a horizontal partition, and a multi-stage temperature-controlled jacket system. A high-shear stirrer is installed at the bottom of the continuous coupling device body, and the two raw material inlets of diazo liquid and esterification liquid are aligned with the shear head of the high-shear stirrer; a heat dissipation coil is installed in the area where the high-shear stirrer is located, and a first-section temperature control jacket is installed on the outside. The upper part of the continuous coupling device body is divided into multiple independent stirring units by several horizontal partitions. Each stirring unit is equipped with a multi-layer stirring mechanism. A vertical baffle is fixed on the inner wall of the continuous coupling device body. The outer side of the multi-layer stirring unit is provided with a second temperature control jacket (8) and a third temperature control jacket from bottom to top. The scraper blades are assembled in the upper region of the continuous coupling device, and the installation height is higher than the top discharge port of the continuous coupling device. The high-shear agitator area is temperature-controlled by chilled brine, maintaining a reaction temperature of 0-5℃; the lower part of the multi-layer agitator is temperature-controlled by low-temperature water, maintaining a reaction temperature of 10-15℃; the upper part of the multi-layer agitator is temperature-controlled by circulating water, maintaining a reaction temperature of 20-25℃; after the material completes the initiation reaction in the bottom high-shear zone, it overflows from bottom to top in stages, and after undergoing multi-stage gradient temperature reaction, it is continuously discharged from the top outlet.

[0013] By adopting the above technical solution, this device achieves instantaneous homogeneous mixing of diazo liquid and esterification liquid through a bottom high-shear stirrer. Combined with a multi-stage temperature control jacket and heat exchange coils to construct a gradient temperature control system, it sequentially completes the low-temperature initiation at 0~5℃, the medium-temperature main reaction at 10~15℃, and the high-temperature maturation at 20~25℃. The horizontal baffle separates the independent stirring units to suppress material backmixing. Combined with the wall scraper anti-wall structure, the coupled reaction is carried out continuously and stably, effectively improving the reaction conversion rate and product purity.

[0014] Optionally, the high-shear stirrer is vertically installed at the bottom of the continuous coupling device, and the high-shear head speed is 500~5000 rpm, preferably 1000~3000 rpm; the height to diameter ratio of the reaction zone where the high-shear stirrer is located is 1.5~3:1. The reaction chamber corresponding to the high-shear stirrer is configured with a gradient diameter structure that is narrow at the bottom and wide at the top, with a diameter expansion gradient of 5%~15% / 100mm in height, which is used to stabilize the overflow flow rate of materials and suppress material turbulence and reaction fluctuations.

[0015] By adopting the above technical solution, the high-shear structure with adjustable rotation speed can enhance the micro-mixing of the two raw materials. Combined with a specific height-to-diameter ratio and a gradient variable diameter cavity, it can buffer the material flow rate, reduce fluid turbulence, and stabilize the reaction environment in the low-temperature initiation stage at the bottom.

[0016] Optionally, the multi-layer stirring mechanism has no less than 6 layers of blades; the ratio of the distance between adjacent horizontal baffles to the reactor diameter is 1 / 3 to 1:1. The horizontal baffle is provided with an adjustable overflow hole at its center, and each layer of stirring unit forms an independent micro-reaction zone to achieve step-by-step overflow and suppress material back-mixing and short circuit; the diameter of the blade of the multi-layer stirring mechanism is 1 / 3 to 1 / 2 of the diameter of the main body of the continuous coupling device, and the blade adopts one or a combination of axial flow blade and inclined blade disc blade.

[0017] By adopting the above technical solution, multi-layer stirring paddles and horizontal baffles are used to divide the multi-level independent reaction zones. Adjustable overflow holes are used to achieve orderly overflow of materials at each level, effectively suppressing material back-mixing and short-circuiting. Combined with combined paddle blades, the uniformity of material mixing in each layer is improved, ensuring the stable progress of the gradient reaction.

[0018] Optionally, the multi-layer stirring mechanism is an adjustable-angle composite impeller structure. The lower and middle high-concentration reaction zone uses a large-angle inclined blade disc impeller, and the upper and middle maturation zone uses a small-angle axial flow impeller. The adjustable blade angle range is 15°~45°, which is suitable for coupled reaction systems with different material viscosities and raw material ratios.

[0019] By adopting the above technical solution and using an adjustable-angle composite paddle structure, different paddle types and angles are matched in different zones to specifically enhance the material conveying in the mixing and maturation zones of high-concentration materials. This allows for flexible adaptation to coupled reaction systems with different viscosities and ratios, improving the device's versatility and adaptability.

[0020] Optionally, the scraping blades are made of elastic and wear-resistant material, and the gap between the scraping blades and the inner wall of the continuous coupling device is less than 5mm; the blade edges are provided with a micro-arc guide structure, which can realize the self-cleaning of materials on the inner wall, prevent wall adhesion, and prevent retention and deterioration. The heat exchange coil is arranged in the low-temperature reaction zone where the high-shear stirrer is located; the overall diameter of the heat exchange coil is 0.6 to 0.7 times the diameter of the continuous coupling device; the heat exchange coverage area accounts for more than 85% of the cross-sectional area of ​​the shear zone. The multi-segment temperature control jacket system is provided with no less than 3 independent jackets; the bottom high-shear section temperature control jacket is connected to the chilled brine circulation system, the middle layer stirring section temperature control jacket is connected to the low-temperature water circulation system, and the upper layer stirring section temperature control jacket is connected to the normal temperature circulating water system. Temperature sensors and flow sensors are installed at the inlet and outlet of the medium in each section of the temperature control jacket and heat exchange coil, forming a temperature-flow dual closed-loop adaptive temperature control system, with a temperature control accuracy of ±0.5℃ in each temperature zone.

[0021] By adopting the above technical solutions, the elastic scraper removes the material adhering to the cylinder wall, the segmented independent jackets distribute different temperature control media, and a dual closed-loop temperature control system is built based on sensors to accurately control the temperature of each reaction zone, avoiding problems such as material retention and deterioration, coil scaling, and excessive temperature fluctuations, and ensuring a stable and controllable coupling reaction environment.

[0022] Optionally, the multi-segment temperature control jacket system is equipped with a tiered waste heat recovery circulation structure to realize multi-media tiered heat exchange and complementary energy recycling.

[0023] By adopting the above technical solutions, the energy complementarity and recycling between heat exchange media can be realized, the operating load of refrigeration equipment can be reduced, the energy consumption of segmented temperature control processes can be reduced, and the energy-saving and environmental protection performance of the entire coupled reaction device can be improved.

[0024] Optionally, an annular pressure-stabilizing buffer chamber is provided at the top discharge end of the continuous coupling device to form a pressure-stabilizing and graded discharge structure, stabilize the material residence time, eliminate discharge turbulence fluctuations, and avoid short-circuit discharge and excessive retention.

[0025] By adopting the above technical solution, an annular pressure-stabilizing buffer chamber is added at the reactor outlet to rectify and buffer the outflowing reaction liquid, reduce the flow rate fluctuation caused by material turbulence, stabilize the actual residence time of the material inside the device, and avoid the phenomenon of some material short-circuiting and rapid discharge or long-term retention.

[0026] Optionally, the entire continuous coupling device adopts a modular integrated structure, including an independently detachable high-shear reaction module, a multi-layer stirring reaction module, a multi-stage temperature control module, a heat exchange circulation module, and a self-cleaning wall scraping module; each module can be independently disassembled and replaced to adapt to different production capacities and reaction types.

[0027] By adopting the above technical solution In a second aspect, a multi-stage temperature-controlled continuous coupling reaction process, applied to the reaction apparatus according to any one of claims 1 to 8, comprises the following process steps: S1. Precise raw material feeding: Diazo liquid and esterification liquid are fed at constant pressure and constant flow through a high-precision metering feeding system. The two material outlets are aligned with the core turbulent zone of the bottom high-shear stirring head, and instantaneous premixing is achieved through the atomization and diversion structure. S2. Low-temperature shear-induced reaction: Turn on the high-shear stirrer and control the speed at 1000~3000 rpm. The temperature of the bottom reaction zone is stably controlled at 0~5℃ through the heat exchange of frozen brine, so as to realize the ultra-fine homogenization and low-temperature coupling initiation reaction of the material. S3, Gradient heating staged reaction: The reactants overflow from bottom to top and enter the multi-layer stirred reaction unit; the lower and middle units are controlled at 10~15℃ by low temperature water to complete the coupling main reaction; the upper and middle units are controlled at 20~25℃ by circulating water to complete the product ripening and impurity removal reaction. S4. Self-cleaning and stable flow discharge: Throughout the reaction process, the scraper continuously cleans the material adhering to the inner wall, the top pressure stabilizing buffer chamber stabilizes the discharge flow rate, and the mature reaction liquid is continuously and stably discharged from the top outlet, completing the continuous coupled reaction production.

[0028] By adopting the above technical solution, the process relies on the device to complete the precise delivery, atomization, and premixing of raw materials. It relies on high shear to achieve ultra-fine homogeneous mixing of two-phase materials. The reaction temperature is controlled in stages to carry out low-temperature initiation, medium-temperature main reaction, and high-temperature ripening and impurity removal in sequence. The entire process is coordinated with the wall scraping structure to remove the inner wall adhering substances. The discharge end is stabilized and rectified, and the material residence time is strictly controlled to complete the multi-stage coupling reaction in an orderly manner. This enables the long-term continuous preparation of coupling products, reduces by-products, and ensures the stability of the finished product quality.

[0029] Optionally, the entire process adopts an intelligent closed-loop control system to collect parameters such as temperature, medium flow rate, stirring speed, and material level in each temperature zone in real time, so as to realize adaptive process parameter optimization and early warning and interlock protection for faults such as over-temperature, material blockage, and heat exchange failure.

[0030] By adopting the above technical solutions, the entire process uses an intelligent closed-loop control system to collect multiple operating parameters in real time and adaptively adjust various process parameters; it can promptly identify over-temperature, material blockage, and heat exchange faults, triggering early warnings and interlock protection, ensuring the safe, stable, and automated operation of the entire continuous coupled reaction process.

[0031] In summary, this application includes at least one of the following beneficial technical effects: 1. This application adopts a bottom high-shear feeding and mixing combined with a segmented gradient temperature control structure to complete the low-temperature initiation, medium-temperature main reaction and high-temperature curing processes in sequence. The materials are fully mixed, which can suppress the generation of side reactions and effectively improve the conversion rate of coupling reaction and the purity of products.

[0032] 2. Relying on horizontal baffles to separate multiple independent stirring units, adjustable overflow holes, and zoned matching stirring paddles, it suppresses material backmixing and short-circuit flow; the elastic scraper structure continuously cleans the material adhering to the cylinder wall, preventing material retention and deterioration, and is suitable for long-term continuous operation of high viscosity reaction systems.

[0033] 3. The double-layer heat exchange coil and multi-section independent temperature control jacket, combined with a dual closed-loop temperature control system, provide high temperature control accuracy.

[0034] 4. The pressure-stabilizing buffer chamber at the discharge end stabilizes the material flow rate. The modular and detachable structure facilitates maintenance and disassembly. Components can be replaced according to production capacity and reactants. The equipment is highly versatile and adaptable to various coupling processing conditions.

[0035] 5. The entire process is equipped with an intelligent closed-loop control system, which monitors operating parameters in real time, automatically optimizes operating conditions, and implements fault interlock protection, reducing manual intervention and ensuring safe and stable continuous production and uniform and stable batch product quality. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of an embodiment of this application.

[0037] Explanation of reference numerals in the attached drawings: 1. Continuous coupling device; 2. High-shear agitator; 3. Heat exchange coil; 4. Horizontal baffle; 5. Multi-layer agitator; 6. Wall scraper blade; 7. Vertical baffle; 8. Temperature control jacket. Detailed Implementation

[0038] The following is in conjunction with the appendix Figure 1 This application will be described in further detail.

[0039] This application discloses a multi-stage temperature-controlled continuous coupling reaction device and process. For example... Figure 1 As shown, the continuous coupling reaction device includes a continuous coupling device 1. Inside the continuous coupling device 1, from bottom to top, are arranged a high-shear stirrer 2, a heat exchange coil 3, a multi-layer stirrer 5, a horizontal baffle 4, a vertical baffle 7, and a wall scraping impeller 6. A temperature control jacket 8 is provided on the outer periphery of the continuous coupling device 1. A high-shear stirrer 2 is installed at the bottom of the continuous coupling device 1. The high-shear stirrer 2 is used to instantaneously and intensely mix the diazo liquid and coupling liquid entering the bottom of the reactor, ensuring rapid and uniform contact between the two reactants, shortening the mixing time, reducing local concentration differences, and improving the mass transfer efficiency in the initial stage of the coupling reaction. Preferably, the shear head rotation speed of the high-shear stirrer 2 is 1000–3000 rpm, and the ratio of the height of the high-shear reaction zone to the reactor diameter is 1.5–3:1, ensuring sufficient mixing and residence space in the high-shear zone. The heat exchange coil 3 is located in the area where the high-shear stirrer 2 is located. Preferably, the diameter of the coil is 0.6 to 0.7 times the inner diameter of the continuous coupling device 1. The heat exchange coil 3 and the temperature control jacket 8 corresponding to the high-shear area together constitute an enhanced heat exchange system. The high-shear area uses chilled brine as the heat exchange medium to keep the temperature of the high-shear reaction area stable at 0 to 5°C, remove the heat of reaction released by the coupling reaction in time, avoid local overheating and decomposition of diazo components, and improve reaction selectivity. A multi-layered agitator 5 is installed above the high-shear reaction zone. The multi-layered agitator 5 consists of no fewer than six layers, and each layer is separated by a horizontal partition 4 to form multiple relatively independent stirring units. The horizontal partition 4 restricts axial back mixing and allows the reaction liquid to overflow sequentially into the stirring unit above it, achieving an approximate plug flow reaction mode. Preferably, the ratio of the distance between adjacent horizontal partitions 4 to the reactor diameter is 1 / 3 to 1. The multi-layer agitator 5 adopts one or a combination of axial flow impeller and inclined blade disc impeller. The diameter of the impeller blade accounts for 1 / 3 to 1 / 2 of the inner diameter of the continuous coupling device 1. Through continuous agitation, the slurry is kept in uniform suspension, reducing sedimentation and local concentration fluctuations, so that the coupled slurry maintains a stable mass transfer state in each reaction unit. The inner wall of the continuous coupling device 1 is provided with several vertical baffles 7 along the axial direction. The vertical baffles 7 are used to weaken the swirling of the reaction liquid, enhance radial mixing, increase the degree of turbulence, further enhance the mixing effect of the multi-layer stirrer 5, and avoid the formation of an overall rotating flow field. A scraper blade 6 is installed at the top of the multi-layer agitator 5. The scraper blade 6 is installed at a height higher than the top outlet of the reactor. The gap between the scraper blade 6 and the inner wall of the reactor is less than 5mm. The scraper blade 6 rotates synchronously with the agitator, which can continuously scrape off the high-viscosity coupled slurry adhering to the reactor wall, reduce scaling and material accumulation on the wall surface, improve heat transfer efficiency, and avoid affecting product quality due to long-term material accumulation. The continuous coupling device 1 is equipped with three or more independent temperature control jackets 8. The temperature control jacket 8 corresponding to the high shear reaction zone uses chilled brine for heat exchange. The multiple temperature control jackets 8 corresponding to the multi-layer stirred reaction zone use low-temperature water and circulating water for temperature regulation from bottom to top, respectively, to achieve a segmented temperature control method that gradually increases the temperature along the reaction process.

[0040] This application also provides a process for performing a continuous coupling reaction using the above-mentioned continuous coupling reaction apparatus, which includes the following steps: First, the diazo liquid and the esterification liquid are continuously fed to the bottom of the continuous coupling device 1. The raw material inlet is set near the high shear stirrer 2, and the raw material outlet is located in the shearing area of ​​the high shear head, so that the two materials are immediately subjected to high shear after entering, achieving instantaneous uniform mixing and starting the coupling reaction. Subsequently, under the combined action of the heat exchange coil 3 and the corresponding temperature control jacket 8, the temperature of the high shear reaction zone is controlled at 0-5℃, and the large amount of heat released by the reaction is quickly removed, with most of the diazo components completing the reaction in this zone. After the initial coupling reaction is completed, the slurry overflows continuously upwards due to the liquid level difference, and passes through the independent stirring units formed by each layer of horizontal baffles 4 in sequence. Under the continuous stirring of the multi-layer stirrer 5 and the enhanced mixing effect of the vertical baffle 7, the slurry remains in a uniformly dispersed state and gradually completes the remaining coupling reaction. During the continuous upward flow of the slurry, the temperature control jacket 8 of each section uses heat exchange medium of different temperatures to implement segmented temperature control. The temperature of the lower reaction zone in the multi-layer stirring is controlled at 10-15℃, and the temperature of the upper reaction zone in the multi-layer stirring is controlled at 20-25℃. Since the concentration of diazonium liquid in the system is already low at this time, increasing the reaction temperature will not significantly increase the risk of diazonium component decomposition. At the same time, it can effectively reduce the viscosity of the coupling slurry, improve the mass transfer and heat transfer efficiency, and further improve the coupling reaction rate. Finally, the reaction liquid is continuously discharged from the top outlet of the continuous coupling device 1, and then enters the subsequent crystallization process. After heating and crystallization, it is sequentially subjected to pressure filtration and washing to finally obtain the target dye filter cake.

[0041] Example 1

[0042] use Figure 1 The continuous coupling reaction apparatus shown is used for the continuous coupling reaction of 2-cyano-4-nitroaniline.

[0043] Among them, the high-shear stirrer 2 is installed at the bottom of the continuous coupling device 1, the shear head speed is 2000 rpm, the ratio of the height of the high-shear reaction zone to the diameter of the reactor is 2:1, the multi-layer stirrer 5 is set with a total of 8 layers, and the adjacent two layers are separated by horizontal partitions 4 to form independent reaction units. The ratio of the distance between adjacent horizontal partitions 4 to the diameter of the reactor is 1:2. The multi-layer stirrer 5 adopts an axial flow impeller, and the impeller diameter is 1 / 2 of the reactor diameter. Vertical baffles 7 are evenly arranged on the inner wall of the continuous coupling device 1 to enhance the mixing effect. The wall scraper blade 6 is installed at the top, with an installation height higher than the top discharge port. The distance between the wall scraper blade 6 and the vessel wall is 4mm. A heat exchange coil 3 is installed in the high shear zone, with a diameter of approximately 0.7 times the reactor diameter. The temperature control jacket 8 in the high shear zone uses chilled brine. The two temperature control jackets 8 in the multi-layer stirring zone use low-temperature water and circulating water, respectively. During the reaction, a mixture of 2-cyano-4-nitroaniline diazonium salt and N-ethyl-N-cyanoethylaniline aqueous solution is continuously fed into the shear zone of high-shear stirrer 2, wherein the mass ratio of water, additives and N-ethyl-N-cyanoethylaniline is 11:0.05:1, and the molar ratio of diazonium component to coupling component is 0.99:1. The temperature in the high-shear zone is controlled at 0℃; the temperature in the lower part of the multi-layer stirring is controlled at 10℃; the temperature in the upper part of the multi-layer stirring is controlled at 20℃; the total residence time is approximately 1 hour. After the reaction solution is continuously discharged, it enters the crystallization, pressure filtration, and washing processes to finally obtain the dye filter cake. The test results show that the filter cake yield obtained in this embodiment is 1461 kg, which is about 5.1% higher than that of the comparative example; the product strength reaches 460%, which is about 5.7% higher than that of the comparative example; the product color is basically the same as that of the comparative example, indicating that the continuous coupling process of the present invention can significantly improve the product yield and color strength while maintaining the stability of the product color.

[0044] Example 2

[0045] The same continuous coupling apparatus was used to carry out the continuous coupling reaction.

[0046] In this embodiment, the high-shear agitator 2 is rotated at 2500 rpm, the height to diameter ratio of the high-shear zone is 1.5:1, the multi-layer agitator 5 is set with 9 layers, the spacing between adjacent horizontal baffles 4 is 2:3 to the reactor diameter, the impeller is an axial flow impeller with a diameter of 1 / 2 of the reactor diameter, the wall scraper 6 is 4 mm away from the wall, the high-shear zone is equipped with a heat exchange coil 3, and the temperature control jacket 8 is configured in the same way as in embodiment 1. During the reaction, the temperature in the high-shear zone was controlled at 3℃, the temperature in the lower part of the multi-layer stirring was controlled at 13℃, and the temperature in the middle and upper parts was controlled at 23℃. The total residence time of the continuous reaction was about 1 hour. After the reaction, crystallization, pressure filtration and washing were carried out in sequence. The yield of the filter cake reached 1470 kg, which is about 5.7% higher than the comparative example; the product strength reached 464%, which is about 6.7% higher than the comparative example; and the product color remained consistent.

[0047] This application integrates a high-shear agitator 2, a heat exchange coil 3, a horizontal baffle 4, a multi-layer agitator 5, a wall scraper 6, a vertical baffle 7, and a multi-segment temperature control jacket 8 into a continuous coupling device 1, forming a continuous coupling process that combines high-shear rapid mixing, layered continuous reaction, and segmented temperature control. Compared with the traditional intermittent coupling process, it can significantly shorten the reaction residence time, improve production efficiency, reduce equipment size, improve the mass and heat transfer conditions of the slurry, increase the coupling reaction rate and product yield, and enhance the color strength of the product. It is especially suitable for the continuous coupling production of high-viscosity slurry systems.

[0048] The implementation principle of the multi-segment temperature-controlled continuous coupling reaction device and process in this application embodiment is as follows: A continuous coupling device is used to integrate functions such as high-shear mixing, multi-layer continuous stirring, segmented temperature control and enhanced heat exchange into the same reaction system, so that the coupling reaction can be carried out continuously according to the kinetic characteristics of different reaction stages. During the reaction, the diazo liquid and the coupling liquid first enter the high-shear stirring zone at the bottom of the device. Under the action of the high-shear stirrer, instantaneous uniform mixing is achieved, eliminating local concentration gradients and improving reactant contact efficiency. The temperature control jacket and heat exchange coil are used to quickly remove the large amount of reaction heat released in the early stage of the coupling reaction, so that the high-shear reaction zone is always kept at a low temperature of 0-5°C, thereby effectively inhibiting the thermal decomposition of diazo components and improving the selectivity and reaction efficiency of the coupling reaction. After the initial rapid coupling, the reaction liquid continuously overflows upwards into the multi-layer stirred reaction zone due to the liquid level difference. Under the combined action of continuous stirring by the multi-layer stirrer, elimination of swirling by vertical baffles, and separation of multiple relatively independent stirring units by horizontal baffles, the reaction liquid flows step by step in an approximately piston flow manner, reducing back mixing and making the reaction conditions at each stage more stable. At the same time, as the concentration of diazo components continues to decrease, the temperature control jackets of each section use different heat exchange media such as low-temperature water and circulating water to implement segmented temperature control of the reaction liquid from low to high, so that the reaction temperature is gradually increased to 10-25℃. Since the concentration of diazo components is low in the later stages, increasing the reaction temperature will not significantly increase its decomposition risk. On the contrary, it can reduce the viscosity of the coupling slurry, enhance the material flowability, improve mass and heat transfer efficiency, and further accelerate the coupling reaction rate, so as to achieve efficient continuous reaction process. In addition, the scraper blades set at the top of the reactor can continuously remove the high-viscosity slurry adhering to the reactor wall, reduce wall adhesion and scaling, and maintain the equipment's good heat exchange performance and continuous operation stability; the heat exchange coil and the multi-stage temperature control jacket work together to achieve precise temperature control in different reaction zones, so that the entire coupling reaction is always under the best process conditions. This application achieves continuous and stable operation of the coupling reaction through the synergistic combination of high-shear rapid mixing, layered continuous reaction, segmented gradient temperature control, enhanced heat transfer, and anti-wall adhesion structure. It can significantly shorten the reaction residence time, reduce equipment volume, improve production efficiency, and reduce energy consumption. At the same time, it can improve the dye filter cake yield and product strength, and ensure the color consistency of the product. It is especially suitable for continuous coupling production of high-viscosity slurry systems.

[0049] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A multi-stage temperature-controlled continuous coupling reaction device, characterized in that: It includes a continuous coupling device (1) body, a high shear stirrer (2), a heat exchange coil (3), a multi-layer stirring mechanism (5), a wall scraper (6), a vertical baffle (7), a horizontal baffle (4), and a multi-segment temperature control jacket system (8). The continuous coupling device (1) has a high-shear stirrer (2) installed at the bottom of its main body. The two raw material inlets of diazo liquid and esterification liquid are aligned with the shear head of the high-shear stirrer (2). The area where the high-shear stirrer (2) is located has a heat exchange coil (3) and a first-stage temperature control jacket (8) is installed on the outside. The upper part of the continuous coupling device (1) is divided into multiple independent stirring units by several horizontal partitions (4). Each stirring unit is equipped with a multi-layer stirring mechanism (5). A vertical baffle (7) is fixed on the inner wall of the continuous coupling device (1). The outer side of the multi-layer stirring unit is provided with a second temperature control jacket (8) and a third temperature control jacket (8) from bottom to top. The scraper blade (6) is mounted on the upper part of the continuous coupling device (1) and is installed at a height higher than the top discharge port of the continuous coupling device (1); Among them, the high shear stirrer (2) is located in the area where the temperature is controlled by the temperature of the frozen brine, and the reaction temperature is controlled at 0~5℃; the lower part of the multi-layer stirring mechanism (5) is controlled by the temperature of the low temperature water, and the reaction temperature is controlled at 10~15℃; the upper part of the multi-layer stirring mechanism (5) is controlled by the temperature of the temperature of the reaction of the circulating water, and the reaction temperature is controlled at 20~25℃; after the material completes the initiation reaction in the bottom high shear zone, it overflows from bottom to top in stages, and after multi-stage gradient temperature reaction, it is continuously discharged from the top outlet.

2. The multi-stage temperature-controlled continuous coupling reaction device according to claim 1, characterized in that: The high-shear stirrer (2) is vertically installed at the bottom of the continuous coupling device (1), and the high-shear head speed is 500~5000rpm, preferably 1000~3000rpm; the height to diameter ratio of the reaction zone where the high-shear stirrer (2) is located is 1.5~3:1; The reaction chamber corresponding to the high shear stirrer (2) is set as a gradient variable diameter structure with a narrow bottom and a wide top, and the expansion gradient is 5%~15% / 100mm in height, which is used to stabilize the overflow flow rate of materials and suppress material turbulence and reaction fluctuations.

3. The multi-stage temperature-controlled continuous coupling reaction device according to claim 1, characterized in that: The multi-layer stirring mechanism (5) has no less than 6 layers of blades; the ratio of the spacing between adjacent horizontal baffles (4) to the reactor diameter is 1 / 3 to 1:1; The horizontal baffle (4) is provided with an adjustable overflow hole in the center, and each layer of stirring unit forms an independent micro-reaction zone to achieve step-by-step overflow and suppress material back-mixing and short circuit; the blade diameter of the multi-layer stirring mechanism (5) is 1 / 3 to 1 / 2 of the main body diameter of the continuous coupling device (1), and the blade adopts one or a combination of axial flow blade and inclined blade disc blade.

4. The multi-stage temperature-controlled continuous coupling reaction device according to claim 3, characterized in that: The multi-layer stirring mechanism (5) is an adjustable tilt angle composite paddle structure. The middle and lower high-concentration reaction zone adopts a large tilt angle oblique blade disc paddle, and the middle and upper maturation zone adopts a small tilt angle axial flow paddle. The adjustable tilt angle range of the paddle blade is 15°~45°, which is suitable for coupling reaction systems with different material viscosities and raw material ratios.

5. The multi-stage temperature-controlled continuous coupling reaction device according to claim 1, characterized in that: The scraping blade (6) is made of elastic and wear-resistant material, and the gap between the scraping blade (6) and the inner wall of the continuous coupling device (1) is less than 5mm. The heat exchange coil (3) is arranged in the low-temperature reaction zone where the high-shear stirrer (2) is located; the overall diameter of the heat exchange coil (3) is 0.6 to 0.7 times the diameter of the continuous coupling device (1), and the heat exchange coverage area accounts for more than 85% of the cross-sectional area of ​​the shear zone. The multi-segment temperature control jacket system (8) is provided with no less than 3 independent jackets; the bottom high shear section temperature control jacket (8) is connected to the frozen brine circulation system, the middle layer stirring section temperature control jacket (8) is connected to the low temperature water circulation system, and the upper layer stirring section temperature control jacket (8) is connected to the normal temperature circulating water system. Temperature sensors and flow sensors are installed at the inlet and outlet of the medium in each section of the temperature control jacket (8) and heat exchange coil (3) to form a temperature-flow dual closed-loop adaptive temperature control system, and the temperature control accuracy of each temperature zone can reach ±0.5℃.

6. The multi-stage temperature-controlled continuous coupling reaction device according to claim 1, characterized in that: The continuous coupling device (1) has an annular pressure stabilizing buffer chamber at the top discharge end to form a pressure stabilizing discharge structure, stabilize the material residence time, eliminate discharge turbulence fluctuations, and avoid short-circuit discharge and excessive retention.

7. The multi-stage temperature-controlled continuous coupling reaction device according to claim 1, characterized in that: The entire continuous coupling device (1) adopts a modular integrated structure, including an independent and detachable high shear reaction module, a multi-layer stirring reaction module, a multi-stage temperature control module, a heat exchange circulation module, and a self-cleaning wall scraping module; each module can be independently disassembled and replaced to adapt to different production capacities and reaction types.

8. A multi-stage temperature-controlled continuous coupling reaction process, applied to the reaction apparatus according to any one of claims 1 to 8, characterized in that: The process includes the following steps: S1. Precise raw material feeding: Diazo liquid and esterification liquid are fed at constant pressure and constant flow through a high-precision metering feeding system. The two material outlets are aligned with the core turbulent zone of the bottom high-shear stirring head, and instantaneous premixing is achieved through the atomization and diversion structure. S2. Low-temperature shear-induced reaction: Turn on the high-shear stirrer and control the speed at 1000~3000 rpm. The temperature of the bottom reaction zone is stably controlled at 0~5℃ through heat exchange with frozen brine, so as to realize the ultra-fine homogenization and mixing of materials and the low-temperature coupled initiation reaction. S3, Gradient heating staged reaction: The reactants overflow from bottom to top and enter the multi-layer stirred reaction unit; the middle and lower unit is controlled at 10~15℃ by low temperature water to complete the coupled main reaction; the middle and upper unit is controlled at 20~25℃ by circulating water to complete the product ripening and impurity removal reaction. S4. Self-cleaning and stable flow discharge: Throughout the reaction process, the scraper continuously cleans the material adhering to the inner wall, the top pressure stabilizing buffer chamber stabilizes the discharge flow rate, and the mature reaction liquid is continuously and stably discharged from the top outlet, completing the continuous coupled reaction production.

9. The multi-stage temperature-controlled continuous coupling reaction process according to claim 8, characterized in that: The entire process adopts an intelligent closed-loop control system, which collects temperature, medium flow rate, stirring speed and material level parameters in each temperature zone in real time, so as to realize adaptive process parameter optimization and early warning and interlock protection for over-temperature, material blockage and heat exchange failure.

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