An integrated reaction apparatus for the continuous chlorination production of 2,4,6-trichloroaniline

Abstract

This invention discloses an integrated reaction apparatus for the continuous chlorination preparation of 2,4,6-trichloroaniline, relating to the field of chemical equipment technology. It includes a preparation vessel, the outlet of which, along with a metering pump, is connected to the inlet of a microchannel reactor via an industrial chlorine gas pipeline. The outlet of the microchannel reactor is connected to a temporary storage vessel. An exhaust pipe is located above the temporary storage vessel and connected to an air compressor. The outlet of the air compressor is connected to the inlet of the microchannel reactor. A discharge port below the temporary storage vessel is connected to a centrifuge. The inlet of a separator is connected to the outlet of the centrifuge. The separator is connected to a magnetic circulation pump, and its outlet is connected to the preparation vessel via the magnetic circulation pump. This invention, by incorporating an air compressor and a magnetic circulation pump, allows for the reuse of byproducts such as chlorine, dilute hydrochloric acid, and water generated during the preparation process, forming a closed-loop preparation system. This effectively solves the problem of difficult waste gas and waste acid treatment and improves the safety of the apparatus.

Description

Technical Field

[0001] This application relates to the field of chemical equipment technology, and in particular to an integrated reaction apparatus for the continuous chlorination preparation of 2,4,6-trichloroaniline. Background Technology

[0002] 2,4,6-Trichloroaniline is an important fine chemical intermediate, widely used in pesticides, dyes, and pharmaceuticals. Currently, industrial production mainly employs the aniline chlorination process, but existing reaction equipment suffers from the following problems: 1. Low mass transfer efficiency: Traditional batch reactors have a small gas-liquid contact area and a mass transfer coefficient of only 0.02~0.05s⁻¹, resulting in a reaction time of 8~12 hours and low production efficiency.

[0003] 2. Low chlorine utilization rate: The existing process typically has a chlorine utilization rate of only 82-85%, with a large amount of chlorine being emitted without reacting. This not only wastes resources but also requires a complex tail gas treatment system, increasing production costs.

[0004] 3. Difficulty in waste acid treatment: The preparation reaction generates a large amount of dilute hydrochloric acid (concentration of about 18~22%), and traditional neutralization treatment methods produce a large amount of chlorine-containing waste salt, resulting in significant environmental pressure. Although the existing patent CN106866427A proposes a method for regenerating chlorine by hydrogen peroxide oxidation, hydrogen peroxide is easily decomposed under high temperature conditions, and the generated chlorine gas has a high oxygen content (>2%), posing an explosion risk.

[0005] 4. Unstable product purity: Due to insufficient reaction control precision, the product often contains byproducts such as monochloro and dichloro, and the purity is generally 95~97%, which is difficult to meet the needs of high-end applications.

[0006] 5. High safety risks: Chlorine is a highly toxic gas. Traditional processes involve large chlorine storage volumes, which pose a high risk of leakage and threaten the safety of operators and the environment. Utility Model Content

[0007] The present invention aims to provide an integrated system for the continuous chlorination of aniline to prepare 2,4,6-trichloroaniline in a highly efficient, safe and environmentally friendly manner, in order to solve the problems of low mass transfer efficiency, low chlorine utilization rate, difficult treatment of waste acid, unstable product purity and high safety risks in the prior art.

[0008] This invention provides an integrated reaction apparatus for the continuous chlorination preparation of 2,4,6-trichloroaniline, comprising an industrial chlorine gas pipeline equipped with a solenoid valve, a preparation vessel, a microchannel reactor, a temporary storage vessel, a centrifuge, a separator, an electrolytic cell, a metering pump, an air compressor, and a magnetic circulation pump. The outlet of the preparation vessel is connected to the inlet of the microchannel reactor via the metering pump and the industrial chlorine gas pipeline. The outlet of the microchannel reactor is connected to the temporary storage vessel. A gas-liquid separator is located above the temporary storage vessel and connected to the air compressor. The outlet of the air compressor is connected to the inlet of the microchannel reactor. The discharge port below the temporary storage vessel is connected to the centrifuge. The inlet of the separator is connected to the outlet of the centrifuge. The organic phase outlet of the separator is connected to the preparation vessel via the magnetic circulation pump. The aqueous phase outlet of the separator is connected to the electrolytic cell. An exhaust pipe is located above the electrolytic cell and leads to the air compressor.

[0009] Preferably, the microchannel reactor is provided with a zoned temperature control jacket, which includes a heating zone and a cooling zone. The heating zone is located at the inlet end of the microchannel reactor, and the cooling zone is located at the outlet end of the microchannel reactor. The length ratio of the heating zone to the cooling zone is (5-8):4.

[0010] Preferably, the temperature control range of the heating zone is 60-65℃, and the temperature control range of the cooling zone is 10-15℃.

[0011] Preferably, the system also includes a controller, which is electrically connected to the metering pump, the magnetic circulation pump, the air compressor, and the solenoid valve.

[0012] Preferably, the microchannel reactor is equipped with multiple temperature sensors, which are connected to a controller.

[0013] Preferably, pressure sensors are provided at the front and rear ends of the microchannel reactor, and the pressure sensors are electrically connected to the controller.

[0014] Preferably, the exhaust pipe is equipped with a hydrogen trap and an explosion-proof flame arrester, and the hydrogen trap is also equipped with a hydrogen concentration detector and an inert gas automatic release device.

[0015] Preferably, the electrolytic cell has a closed structure, and multiple chlorine leak detectors are provided on the outer surface of the electrolytic cell.

[0016] The beneficial effects of this utility model are: This invention, by incorporating an air compressor and a magnetic circulation pump, can reuse the byproducts chlorine, dilute hydrochloric acid, and water generated during the preparation process, forming a closed-loop preparation system. This effectively solves the problem of difficult-to-treat waste gas and waste acid, and improves the safety of the device.

[0017] This invention uses a pressure sensor to monitor the pressure inside the temporary storage vessel in real time and feeds the feedback to the controller to regulate the solenoid valve on the industrial chlorine pipeline. This allows for the phased, pulsed introduction of chlorine, maintaining the system pressure at +0.5 to +1.5 kPa. It effectively avoids excessive chlorine and localized overheating, increasing chlorine utilization from 82% to 98.2%.

[0018] This invention, by setting up an electrolytic cell, can further electrolyze and reduce the large amount of dilute hydrochloric acid generated in the preparation reaction into chlorine gas. The high-purity chlorine gas can then be reintroduced into the microchannel reactor for utilization using an air compressor. This not only solves the problem of handling large amounts of dilute hydrochloric acid, but also allows for its further utilization, making it highly valuable for promotion. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure and connection relationship of this utility model.

[0020] The components in the diagram are numbered as follows: 1. Preparation vessel; 2. Metering pump; 3. Industrial chlorine gas pipeline; 4. Microchannel reactor; 5. Temporary storage vessel; 6. Centrifuge; 7. Separator; 8. Magnetic circulation pump; 9. Air compressor; 10. Electrolytic cell; 11. Temperature sensor; 12. Pressure sensor; 13. Zoned temperature control jacket; 14. Gas-liquid separator; 15. Exhaust pipeline. Detailed Implementation

[0021] This invention provides an integrated reaction apparatus for the continuous chlorination preparation of 2,4,6-trichloroaniline, comprising an industrial chlorine gas pipeline 3, a preparation vessel 1, a microchannel reactor 4, a temporary storage vessel 5, a centrifuge 6, a separator 7, an electrolytic cell 10, a metering pump, an air compressor 9, and a magnetic circulation pump 8. The outlet of the preparation vessel 1 is connected to the inlet of the microchannel reactor 4 via the metering pump and the industrial chlorine gas pipeline 3. The outlet of the microchannel reactor 4 is connected to the temporary storage vessel 5. A gas-liquid separator 14 is provided above the temporary storage vessel 5 and connected to the air compressor 9. The outlet of the air compressor 9 is connected to the inlet of the microchannel reactor 4. The discharge port below the temporary storage vessel 5 is connected to the centrifuge 6. The inlet of the separator 7 is connected to the outlet of the centrifuge 6. The organic phase outlet of the separator 7 is connected to the preparation vessel 1 via the magnetic circulation pump 8. The aqueous phase outlet of the separator 7 is connected to the electrolytic cell 10. An exhaust pipe 15 is provided above the electrolytic cell 10, and the exhaust pipe 15 leads to the air compressor 9.

[0022] The centrifuge 6 is used to separate the solid and liquid phases of the discharged material. The solid phase is 2,4,6-trichloroaniline. The separator 7 further separates the liquid phase of the centrifuge 6 into an organic phase and an aqueous phase. The organic phase is transported to the preparation vessel 1 for reuse via a magnetic circulation pump 8. The aqueous phase is fed into an electrolytic cell 10 to electrolyze the dilute hydrochloric acid in the aqueous phase into hydrogen and chlorine. The hydrogen and chlorine are then recycled to the microchannel reactor 4 via an air compressor 9, effectively treating and recycling chlorine and dilute hydrochloric acid.

[0023] The microchannel reactor 4 selected in this invention adopts a composite structure of nickel-based alloy substrate and silicon carbide inner coating. The inner coating thickness is 50~100μm, the temperature resistance can reach 300℃, and the resistance to strong acid corrosion is excellent.

[0024] The volume of the temporary storage vessel 5 is 1.5 to 2 times that of the microchannel reactor 4; it can be made of Hastelloy C-276 material, which is resistant to chlorine corrosion; the top of the temporary storage vessel 5 is also equipped with a safety pressure relief valve and a gas detector.

[0025] Specifically, the gas-liquid separator 14 is used to separate the unreacted chlorine gas in the temporary storage vessel 5. The gas-liquid separator can be any mature product on the market with a separation efficiency of >99%.

[0026] Specifically, the exhaust pipe 15 is equipped with a hydrogen trap and an explosion-proof flame arrester, and the hydrogen trap is also equipped with a hydrogen concentration detector and an inert gas automatic release device.

[0027] Specifically, the electrolytic cell 10 is a closed structure, and its outer surface is equipped with multiple chlorine leak detectors. When a chlorine leak is detected, the power supply to the pump is immediately cut off, and all valves are controlled to disconnect the pipeline connection to achieve shutdown.

[0028] Specifically, the microchannel reactor 4 is provided with a zoned temperature control jacket 13 around its periphery. The zoned temperature control jacket 13 includes a heating zone and a cooling zone. The heating zone is located at the inlet end of the microchannel reactor 4, and the cooling zone is located at the outlet end of the microchannel reactor 4. The length ratio of the heating zone to the cooling zone is 6:4.

[0029] Specifically, the temperature control range of the heating zone is 60-65℃, which is used to promote the reaction; the temperature control range of the cooling zone is 10-15℃, which is used to inhibit excessive chlorination.

[0030] Specifically, it also includes a controller, which is electrically connected to the metering pump, the magnetic circulation pump 8, the air compressor 9, and the solenoid valve. The controller can be any Reynolds number controller, MCU control chip, or computer control terminal available on the market. In this embodiment, the controller is the JGKY-D501 Reynolds experimental apparatus.

[0031] Specifically, the microchannel reactor 4 is equipped with multiple temperature sensors 11, which are connected to a controller. These sensors monitor the temperature of each section of the microchannel reactor 4 and provide feedback to the controller to adjust the temperature of that section via the zoned temperature control jacket 13.

[0032] Specifically, pressure sensors 12 are installed at the front and rear ends of the microchannel reactor 4, and the pressure sensors 12 are electrically connected to the controller. Based on real-time monitoring of pressure changes during the reaction process, the feedback controller controls the valves of the industrial chlorine pipeline 3 to achieve staged pulsed introduction of chlorine. This not only maintains the system pressure within the range of +0.5~1.5 kPa, but also effectively avoids excessive chlorine and local overheating, increasing the chlorine utilization rate to 98.2%.

[0033] Working Process and Principle: Aniline, the raw material, is mixed with chlorobenzene, the solvent, in the preparation vessel 1. A metering pump 2 is started to deliver the preparation solution to the microchannel reactor 4. Temperature and pressure are monitored at various points in the microchannel reactor 4. The valve of the industrial chlorine gas pipeline 3 is opened to introduce chlorine gas into the microchannel reactor 4 for reaction. During the reaction, the temperature of each stage in the microchannel reactor 4 is monitored in real time, and feedback is used to control the zone temperature control jacket 13 to maintain the reaction temperature at 60~65℃. Simultaneously, the pressure at the inlet and outlet of the microchannel reactor 4 is monitored, and feedback is used to control the valve of the industrial chlorine gas pipeline 3 to achieve staged pulsed introduction of chlorine gas, maintaining the reaction system pressure at +0.5~+1.5 kPa. After the reaction is complete, the product falls into the temporary storage vessel 5 and is then... Gas-liquid separator 14 separates the gas, which is unreacted chlorine. This gas is then transported back to microchannel reactor 4 via air compressor 9 to participate in subsequent preparation reactions. The remaining portion falls into centrifuge 6 to separate the liquid and solid phases. The solid phase is 2,4,6-trichloroaniline. The liquid phase continues to fall into separator 7 to separate the organic and aqueous phases. The organic phase, including aniline and chlorobenzene, is transported to preparation vessel 1 via magnetic circulation pump 8 and added back to the subsequent preparation. The aqueous phase contains a large amount of HCl solution. The HCl solution is passed into electrolytic cell 10 for electrolysis to generate chlorine and hydrogen. During the process of passing through exhaust pipe 15, the hydrogen is absorbed by the gas trap, while the chlorine passes normally and is then transported to microchannel reactor 4 via air compressor 9 to continue participating in the chlorination reaction.

[0034] The above are specific embodiments of this utility model, but the protection scope of this utility model is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in this utility model, based on the technical solution and concept of this utility model, should be covered within the protection scope of the claims of this utility model.

Claims

1. An integrated reaction apparatus for the continuous chlorination preparation of 2,4,6-trichloroaniline, comprising an industrial chlorine gas pipeline, wherein the industrial chlorine gas pipeline is equipped with a solenoid valve, characterized in that: It also includes a preparation vessel, a microchannel reactor, a temporary storage vessel, a centrifuge, a separator, an electrolytic cell, a metering pump, an air compressor, and a magnetic circulation pump. The outlet of the preparation vessel is connected to the inlet of the microchannel reactor via the metering pump and an industrial chlorine gas pipeline. The outlet of the microchannel reactor is connected to the temporary storage vessel. A gas-liquid separator is installed above the temporary storage vessel and connected to the air compressor. The outlet of the air compressor is connected to the inlet of the microchannel reactor. The discharge port below the temporary storage vessel is connected to the centrifuge. The inlet of the separator is connected to the outlet of the centrifuge. The organic phase outlet of the separator is connected to the preparation vessel via the magnetic circulation pump. The aqueous phase outlet of the separator is connected to the electrolytic cell. An exhaust pipe is installed above the electrolytic cell, and the exhaust pipe leads to the air compressor.

2. The integrated reaction apparatus for the continuous chlorination preparation of 2,4,6-trichloroaniline according to claim 1, characterized in that: The microchannel reactor is surrounded by a zoned temperature control jacket, which includes a heating zone and a cooling zone. The heating zone is located at the inlet end of the microchannel reactor, and the cooling zone is located at the outlet end of the microchannel reactor.

3. The integrated reaction apparatus for the continuous chlorination preparation of 2,4,6-trichloroaniline according to claim 2, characterized in that: The length ratio of the heating zone to the cooling zone is (5-8):

4.

4. An integrated reaction apparatus for the continuous chlorination preparation of 2,4,6-trichloroaniline according to any one of claims 1-3, characterized in that: It also includes a controller, which is electrically connected to the metering pump, the magnetic circulation pump, the air compressor, and the solenoid valve.

5. The integrated reaction apparatus for the continuous chlorination preparation of 2,4,6-trichloroaniline according to claim 4, characterized in that: The microchannel reactor is equipped with multiple temperature sensors, which are connected to a controller.

6. The integrated reaction apparatus for the continuous chlorination preparation of 2,4,6-trichloroaniline according to claim 4, characterized in that: Pressure sensors are provided at the front and rear ends of the microchannel reactor, and the pressure sensors are electrically connected to the controller.

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