Safe and environment-friendly nitration reaction system

Abstract

The utility model provides a safe and environment-friendly nitration reaction system which comprises a micro-channel reactor, a dynamic tubular reactor, a first phase splitter, a nitric acid concentration unit, a circulating pump, a temperature sensor and an overtemperature safety interlocking system, a nitric acid outlet of the nitric acid concentration unit is communicated with a nitric acid inlet of the micro-channel reactor and a nitric acid inlet of the dynamic tubular reactor, the temperature sensor is arranged at the nitric acid inlet of the micro-channel reactor and the nitric acid inlet of the dynamic tubular reactor, and the overtemperature safety interlocking system is connected with the temperature sensor. According to the reaction system provided by the utility model, the temperature sensor and the overtemperature safety interlocking system are arranged, so that continuous and stable production is ensured, and the safety of automation and production is improved. And by arranging the first phase splitter and the nitric acid concentration unit, the generation of waste salt is reduced, and the environmental pollution is small.

Description

Technical Field

[0001] The utility model belongs to the technical field of chemical equipment, and in particular relates to a safe and environmentally friendly nitration reaction system. Background Art

[0002] When nitrating aromatic compounds containing electron-donating groups, only nitric acid can be used as the nitrating agent, but nitric acid is generally used in excess. This type of nitration reaction has a fast reaction speed and a large amount of heat release. During production, a large amount of waste acid and acidic wastewater containing organic matter will be produced, which seriously pollutes the environment. If the heat cannot be removed in time during the reaction, side reactions will occur to generate polynitro compounds and oxides, and even spraying and explosions will occur, which are very dangerous. As the country pays more and more attention to safety and environmental protection issues, the nitration reaction process is constantly improving, and it is imperative to find a new reaction system that matches the green and safe nitration process. Utility Model Content

[0003] The utility model provides a nitration reaction system with high energy utilization rate, high safety and green environmental protection, comprising a microchannel reactor, a dynamic tubular reactor, a first phase separator, a nitric acid concentration unit, a circulation pump, a temperature sensor and an over-temperature safety interlock system; the microchannel reactor is provided with a raw liquid inlet, a reaction liquid outlet and at least one nitric acid inlet, the dynamic tubular reactor is provided with a reaction liquid inlet, a nitration liquid outlet and at least one nitric acid inlet, the first phase separator is provided with a nitration liquid inlet, an oil phase outlet and an acid phase outlet, the nitric acid concentration unit is provided with an acid phase inlet, a light component outlet, a nitric acid outlet and a heavy component outlet; the microchannel reactor The reaction liquid outlet of the reactor is connected with the reaction liquid inlet of the dynamic tubular reactor, the nitrating liquid outlet of the dynamic tubular reactor is respectively connected with the nitrating liquid inlet of the first phase separator and the inlet of the circulation pump, the outlet of the circulation pump is connected with the raw liquid inlet of the microchannel reactor, the acid phase outlet of the first phase separator is connected with the acid phase inlet of the nitric acid concentration unit, the nitric acid outlet of the nitric acid concentration unit is connected with the nitric acid inlet of the microchannel reactor and / or the nitric acid inlet of the dynamic tubular reactor, the temperature sensor is arranged at the nitric acid inlet of the microchannel reactor and the dynamic tubular reactor, and the over-temperature safety interlock system is connected with the temperature sensor.

[0004] In an optional embodiment, the over-temperature safety interlock system includes a control system and an interlock device.

[0005] In an optional embodiment, the nitric acid concentration unit includes a primary steamer and a distillation tower; the acid phase inlet of the primary steamer is the acid phase inlet of the nitric acid concentration unit, the discharge port of the primary steamer is connected to the feed port of the distillation tower, and the nitric acid outlet of the distillation tower is the nitric acid outlet of the nitric acid concentration unit.

[0006] In an optional embodiment, it also includes a first washing and separation unit, which includes a first washing kettle and a second phase separator; the feed inlet of the first washing kettle is respectively connected to the oil phase outlet of the first phase separator and the light component outlet of the primary steaming kettle, and the discharge port of the first washing kettle is connected to the feed inlet of the second phase separator.

[0007] In an optional embodiment, it also includes a second washing and separation unit, which includes a second washing kettle and a solid-liquid separator; the feed inlet of the second washing kettle is respectively connected to the heavy component outlet of the distillation tower and the acid phase outlet of the second phase separator, the discharge port of the second washing kettle is connected to the feed inlet of the solid-liquid separator, and the discharge port of the solid-liquid separator is connected to the feed inlet of the primary steaming kettle.

[0008] In an optional embodiment, it also includes a preheater; the acid phase outlet of the first phase separator is connected to the feed inlet of the preheater, the discharge port of the preheater is connected to the acid phase inlet of the primary steamer, the nitric acid outlet of the distillation tower is connected to the heat medium inlet of the preheater, and the heat medium outlet of the preheater is connected to the nitric acid inlet of the microchannel reactor and / or the nitric acid inlet of the dynamic tubular reactor.

[0009] In an optional embodiment, it also includes a distillation kettle and a mixing kettle; the feed inlet of the distillation kettle is connected to the discharge port of the second phase separator, the solvent outlet of the distillation kettle is connected to the solvent inlet of the mixing kettle, and the discharge port of the mixing kettle is connected to the raw material liquid inlet of the microchannel reactor.

[0010] In an optional embodiment, the temperature sensor includes at least a first temperature sensor and a second temperature sensor; the first temperature sensor is arranged at the nitric acid inlet of the microchannel reactor, and the second temperature sensor is arranged at the nitric acid inlet of the dynamic tubular reactor.

[0011] Compared with the prior art, the technical solution provided by the utility model has the following advantages:

[0012] 1. The reaction system provided by the utility model adopts a microchannel reactor and a dynamic tubular reactor connected in series to carry out nitration reaction, and uses a circulating pump to force the reaction solution to circulate in the microchannel reactor and the dynamic tubular reactor, with good mass transfer and heat transfer effects, stable reaction temperature and high safety. Both stages of the reactor are provided with at least one nitric acid inlet, which avoids the potential safety hazard caused by local overheating caused by excessive local nitric acid concentration, and also reduces the generation of by-products such as nitrates and oxides. By providing a temperature sensor and an over-temperature safety interlock system, the reaction temperature is accurately controlled to ensure continuous and stable production, thereby improving the safety of automation and production.

[0013] 2. Through the post-processing devices such as the first phase separator, the nitric acid concentration unit, the first washing and separation unit, and the second washing and separation unit, the nitric acid is concentrated and recycled, and the nitric acid in the product oil phase and the heavy components of the distillation tower is fully recovered and recycled. No waste acid is generated in the reaction system, the generation of waste salt is reduced, and the environmental pollution is small.

[0014] 3. Through heat integration, the recovered nitric acid at the top of the distillation tower is used as the heat medium of the preheater to heat the acid phase separated by the first phase separator, avoiding the problem of steam heat energy waste in the distillation tower and achieving significant energy-saving effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 A schematic diagram of the structure of the device used in Example 1 of the utility model;

[0017] Figure 2 A schematic diagram of the structure of the device used in Example 2 of the present utility model;

[0018] Figure 3 A schematic diagram of the structure of the device used in Example 3 of the present utility model;

[0019] Figure 4 A schematic diagram of the structure of the device used in Example 4 of the utility model;

[0020] Figure 5 This is a schematic diagram of the structure of the device used in Example 5 of the utility model.

[0021] Description of reference numerals:

[0022] 1-microchannel reactor, 2-dynamic tubular reactor, 3-first phase separator, 4-nitric acid concentration unit, 41-primary steam kettle, 42-distillation tower, 5-circulation pump, 6-temperature sensor, 61-first temperature sensor, 62-second temperature sensor, 63-third temperature sensor, 64-fourth temperature sensor, 7-over-temperature safety interlock system, 8-first washing and separation unit, 81-first washing kettle, 82-second phase separator, 9-second washing and separation unit, 91-second washing kettle, 92-solid-liquid separator, 10-preheater, 11-distillation kettle, 12-mixing kettle. DETAILED DESCRIPTION

[0023] The technical solution of the utility model will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0024] In the present invention, unless otherwise clearly specified or limited, the connection mode between various units or devices should be understood in a broad sense. For example, it can be direct pipeline connection, or it can be connected through pipelines connected to conventional conveying, metering, control, and temporary storage equipment such as pumping equipment, metering equipment, valves and pipe fittings, intermediate tanks, etc. It can be fixed connection or detachable connection. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] In the utility model, various components of the production device, such as microchannel reactor, dynamic tubular reactor, phase separator, preheater, primary steam kettle, distillation tower, washing kettle, solid-liquid separator, mixing kettle, as well as pipe fittings, valves, controller, feed pump, receiving tank, etc. can be purchased from the market, but the entire reaction device cannot be purchased from the market and is not known to those skilled in the art.

[0026] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0027] Please refer to Figure 1-Figure 5 The utility model provides a safe and environmentally friendly nitrification reaction system. Example

[0028] This embodiment provides a safe and environmentally friendly nitration reaction system, the structural schematic diagram of which is shown in FIG. Figure 1As shown, it includes a microchannel reactor 1, a dynamic tubular reactor 2, a first phase separator 3, a nitric acid concentration unit 4, a circulation pump 5, a temperature sensor 6, and an over-temperature safety interlock system 7; the microchannel reactor 1 is provided with a raw liquid inlet, a reaction liquid outlet, and at least one nitric acid inlet, the dynamic tubular reactor 2 is provided with a reaction liquid inlet, a nitration liquid outlet, and at least one nitric acid inlet, the first phase separator 3 is provided with a nitration liquid inlet, an oil phase outlet, and an acid phase outlet, and the nitric acid concentration unit 4 is provided with an acid phase inlet, a light component outlet, a nitric acid outlet, and a heavy component outlet; the reaction liquid outlet of the microchannel reactor 1 is connected to the dynamic tubular reactor 2. The reaction liquid inlet is connected, the nitrating liquid outlet of the dynamic tubular reactor 2 is respectively connected with the nitrating liquid inlet of the first phase separator 3 and the inlet of the circulation pump 5, the outlet of the circulation pump 5 is connected with the raw liquid inlet of the microchannel reactor 1, the acid phase outlet of the first phase separator 3 is connected with the acid phase inlet of the nitric acid concentration unit 4, the nitric acid outlet of the nitric acid concentration unit 4 is connected with the nitric acid inlet of the microchannel reactor 1 and / or the nitric acid inlet of the dynamic tubular reactor 2, the temperature sensor 6 is arranged at the nitric acid inlets of the microchannel reactor 1 and the dynamic tubular reactor 2, and the over-temperature safety interlock system 7 is connected with the temperature sensor 6.

[0029] Furthermore, in order to improve the separation efficiency and recover the nitric acid in the acid phase, the nitric acid concentration unit 4 includes a primary steamer 41 and a distillation tower 42. The acid phase inlet of the primary steamer 41 is the acid phase inlet of the nitric acid concentration unit 4, the discharge port of the primary steamer 41 is connected to the feed port of the distillation tower 42, and the nitric acid outlet of the distillation tower 42 is the nitric acid outlet of the nitric acid concentration unit 4.

[0030] In specific implementation, the raw material liquid and nitric acid enter the microchannel reactor 1 for nitration reaction, the generated reaction liquid enters the dynamic tubular reactor 2 to continue the nitration reaction with nitric acid, a part of the nitration liquid flowing out of the dynamic tubular reactor 2 is transported to the microchannel reactor 1 through the circulation pump 5 to participate in the circulation, and a part enters the first phase separator 3 to separate the organic phase and the acid phase, and the separated acid phase enters the primary steamer 41 to evaporate and remove the light component whose main component is water, and then the heavy component at the bottom of the primary steamer 41 enters the distillation tower 42 for distillation and separation of the heavy component to recover concentrated nitric acid, and the concentrated and recovered nitric acid and fresh nitric acid enter the microchannel reactor 1 and the dynamic tubular reactor 2 to continue to participate in the nitration reaction. A temperature sensor 6 is set at the nitric acid inlet of the microchannel reactor 1 and the dynamic tubular reactor 2, and the temperature sensor 6 is connected to the over-temperature safety interlock system 7 to control the amount of heat exchange medium of the continuous flow reactor. If the temperature is over, the feed pump is closed to protect the continuous production device.

[0031] Furthermore, the over-temperature safety interlock system 7 is composed of a control system and a locking device. The control system is used to receive signals from the temperature sensor 6. The interlock device interlocks the control system with the flow pump, alarm device, power switch, feed pump, circulation pump and discharge valve for conveying heat exchange medium. When the temperature exceeds the safety threshold of 50°C, the control system will trigger the interlock device. The interlock device starts the alarm device and adjusts the flow of the heat exchange medium according to the instructions of the control system, and at the same time adjusts the feed flow or circulation flow or closes the feed flow. When the temperature exceeds the safety threshold of 50°C, the interlock device starts the alarm device and opens the discharge valve to transfer hazardous materials according to the instructions of the control system.

[0032] Furthermore, the microchannel reactor 1 has a reaction channel and a heat exchange channel, and the reaction materials flow and react in the reaction channel, and the heat generated by the reaction is taken away by the heat exchange medium flowing through the heat exchange channel. The dynamic tubular reactor 2 structure has a heat exchange chamber and a reaction chamber with a stirring shaft. The reaction chamber is used to provide a place for the material to react. The stirring shaft is provided with a stirring paddle or stirring fin, which plays a role in mass transfer by rotation. The heat exchange chamber is used to exchange heat in the reaction chamber by circulating a heat exchange medium.

[0033] Optionally, the first phase separator 3 is a static phase separator tank with an inclined partition or a disc-type centrifugal phase separator.

[0034] Optionally, the circulation pump 5 is a centrifugal pump or a diaphragm pump.

[0035] Further, the temperature sensor 6 includes at least a first temperature sensor 61 and a second temperature sensor 62;

[0036] Preferably, the temperature sensor 6 further includes a third temperature sensor 63 and a fourth temperature sensor 64 . Example

[0037] This embodiment provides a safe and environmentally friendly nitration reaction system, the structural schematic diagram of which is shown in FIG. Figure 2 As shown, the difference from Example 1 is that this embodiment is further provided with a first washing and separation unit 8, and the first washing and separation unit 8 includes a first washing kettle 81 and a second phase separator 82; the feed port of the first washing kettle 81 is respectively connected to the oil phase outlet of the first phase separator 3 and the light component outlet of the primary steaming kettle 41, and the discharge port of the first washing kettle 81 is connected to the feed port of the second phase separator 82.

[0038] In specific implementation, based on Example 1, the oil phase whose main component is the nitration product separated by the first phase separator 3 contains a small amount of nitric acid. Generally, chemical companies directly use alkali washing to neutralize the nitric acid in the oil phase, which produces a large amount of waste salt that is difficult to handle. The light component whose main component is water evaporated by the nitric acid concentration unit 4 is mixed and washed in the first washing kettle 81 to extract the nitric acid in the oil phase. After separation and washing, the mixed liquid can be passed through the second phase separator 82 to obtain the oil phase product and the pickling liquid.

[0039] Optionally, the second phase separator 82 is a static phase separator tank with an inclined partition or a disc-type centrifugal phase separator. Example

[0040] This embodiment provides a safe and environmentally friendly nitration reaction system, the structural schematic diagram of which is shown in FIG. Figure 3 As shown, the difference from Example 2 is that this embodiment is further provided with a second washing and separation unit 9, which includes a second washing kettle 91 and a solid-liquid separator 92; the feed port of the second washing kettle 91 is respectively connected to the heavy component outlet of the distillation tower 42 and the acid phase outlet of the second phase separator 82, the discharge port of the second washing kettle 91 is connected to the feed port of the solid-liquid separator 92, and the discharge port of the solid-liquid separator 92 is connected to the feed port of the primary steaming kettle 41.

[0041] In specific implementation, on the basis of Example 2, the acid phase separated by the second phase separator 82 enters the second washing kettle 91 and is mixed with the heavy component from the bottom of the distillation tower 42 to extract nitric acid in the heavy component. After washing, the heavy component enters the solid-liquid separator 92 to separate the solid to obtain acid solution. The acid solution is concentrated by the nitric acid concentration unit 4 and reacts with fresh nitric acid as a nitrating agent, which further reduces the generation of waste acid and protects the environment. Example

[0042] This embodiment provides a safe and environmentally friendly nitration reaction system, the structural schematic diagram of which is shown in FIG. Figure 4 As shown, the difference from Example 3 is that this embodiment is further provided with a preheater 10; the acid phase outlet of the first phase separator 3 is connected to the feed port of the preheater 10, the discharge port of the preheater 10 is connected to the acid phase inlet of the primary steamer 41, the nitric acid outlet of the distillation tower 42 is connected to the heat medium inlet of the preheater 10, and the heat medium outlet of the preheater 10 is connected to the nitric acid inlet of the microchannel reactor 1 and / or the nitric acid inlet of the dynamic tubular reactor 2.

[0043] In specific implementation, on the basis of Example 3, the acid phase separated by the first phase separator 3 enters the preheater 10 for preheating, the preheated acid phase is dehydrated by the primary steamer 41 and then enters the distillation tower 42, the recovered nitric acid flowing out of the top of the distillation tower 42 enters the preheater 10 to exchange heat with the acid phase separated by the first phase separator 3, and the condensed recovered nitric acid enters the microchannel reactor 1 and the dynamic tubular reactor 2 to participate in the reaction as a nitrating agent, thereby further improving the energy utilization rate and reducing the production energy consumption.

[0044] Optionally, the preheater 10 is a shell-and-tube heat exchanger or a wound tube heat exchanger. Example

[0045] This embodiment provides a safe and environmentally friendly nitration reaction system, the structural schematic diagram of which is shown in FIG. Figure 5 As shown, the difference from Example 4 is that this embodiment is further provided with a distillation kettle 11 and a mixing kettle 12; the feed port of the distillation kettle 11 is connected to the discharge port of the second phase separator 82, the solvent outlet of the distillation kettle 11 is connected to the solvent inlet of the mixing kettle 12, and the discharge port of the mixing kettle 12 is connected to the raw material liquid inlet of the microchannel reactor 1.

[0046] In specific implementation, on the basis of Example 4, the oil phase washed by the second phase separator 82 enters the distillation kettle 11 to distill out the organic solvent, the organic solvent returns to the mixing kettle 12 and is mixed with the raw material to prepare the raw material liquid and then put into the microchannel reactor 1 for nitration reaction, the concentrated and recovered nitric acid is heat exchanged with the acid phase separated by the first phase separator 3 in the preheater 10, and the condensed recovered nitric acid enters the dynamic tubular reactor 2 as a nitration reagent to participate in the reaction.

[0047] The above description is only a specific embodiment of the present disclosure, so that those skilled in the art can understand or implement the present disclosure. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure will not be limited to the embodiments described herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A safe and environmentally friendly nitration reaction system, characterized in that: include: Microchannel reactor (1), dynamic tubular reactor (2), first phase separator (3), nitric acid concentration unit (4), circulation pump (5), temperature sensor (6), over-temperature safety interlock system (7); The microchannel reactor (1) is provided with a raw liquid inlet, a reaction liquid outlet, and at least one nitric acid inlet; the dynamic tubular reactor (2) is provided with a reaction liquid inlet, a nitration liquid outlet, and at least one nitric acid inlet; the first phase separator (3) is provided with a nitration liquid inlet, an oil phase outlet, and an acid phase outlet; the nitric acid concentration unit (4) is provided with an acid phase inlet, a light component outlet, a nitric acid outlet, and a heavy component outlet; The reaction liquid outlet of the microchannel reactor (1) is connected to the reaction liquid inlet of the dynamic tubular reactor (2); the nitrification liquid outlet of the dynamic tubular reactor (2) is respectively connected to the nitrification liquid inlet of the first phase separator (3) and the inlet of the circulation pump (5); the outlet of the circulation pump (5) is connected to the raw liquid inlet of the microchannel reactor (1); the acid phase outlet of the first phase separator (3) is connected to the acid phase inlet of the nitric acid concentration unit (4); the nitric acid outlet of the nitric acid concentration unit (4) is connected to the nitric acid inlet of the microchannel reactor (1) and / or the nitric acid inlet of the dynamic tubular reactor (2); a temperature sensor (6) is arranged at the nitric acid inlets of the microchannel reactor (1) and the dynamic tubular reactor (2); and an over-temperature safety interlock system (7) is connected to the temperature sensor (6).

2. A safe and environmentally friendly nitration reaction system according to claim 1, characterized in that: The over-temperature safety interlock system (7) comprises a control system and an interlock device.

3. A safe and environmentally friendly nitration reaction system according to claim 1, characterized in that: The nitric acid concentration unit (4) comprises a primary distillation kettle (41) and a distillation tower (42); The acid phase inlet of the primary steamer (41) is the acid phase inlet of the nitric acid concentration unit (4), the discharge port of the primary steamer (41) is connected to the feed port of the distillation tower (42), and the nitric acid outlet of the distillation tower (42) is the nitric acid outlet of the nitric acid concentration unit (4).

4. A safe and environmentally friendly nitration reaction system according to claim 3, characterized in that: It also includes a first washing and separation unit (8), the first washing and separation unit (8) including a first washing tank (81) and a second phase separator (82); The feed inlet of the first washing kettle (81) is respectively connected to the oil phase outlet of the first phase separator (3) and the light component outlet of the primary steaming kettle (41), and the discharge port of the first washing kettle (81) is connected to the feed inlet of the second phase separator (82).

5. A safe and environmentally friendly nitration reaction system according to claim 4, characterized in that: The invention also comprises a second washing and separation unit (9), wherein the second washing and separation unit (9) comprises a second washing tank (91) and a solid-liquid separator (92); The feed inlet of the second washing kettle (91) is respectively connected to the heavy component outlet of the distillation tower (42) and the acid phase outlet of the second phase separator (82); the discharge port of the second washing kettle (91) is connected to the feed inlet of the solid-liquid separator (92); and the discharge port of the solid-liquid separator (92) is connected to the feed inlet of the primary steaming kettle (41).

6. A safe and environmentally friendly nitration reaction system according to claim 3, characterized in that: Also includes a preheater (10); The acid phase outlet of the first phase separator (3) is connected to the feed inlet of the preheater (10), the discharge port of the preheater (10) is connected to the acid phase inlet of the primary steamer (41), the nitric acid outlet of the rectification tower (42) is connected to the heat medium inlet of the preheater (10), and the heat medium outlet of the preheater (10) is connected to the nitric acid inlet of the microchannel reactor (1) and / or the nitric acid inlet of the dynamic tubular reactor (2).

7. A safe and environmentally friendly nitration reaction system according to claim 4, characterized in that: It also includes a distillation kettle (11) and a mixing kettle (12); The feed inlet of the distillation kettle (11) is connected to the discharge port of the second phase separator (82), the solvent outlet of the distillation kettle (11) is connected to the solvent inlet of the mixing kettle (12), and the discharge port of the mixing kettle (12) is connected to the raw material liquid inlet of the microchannel reactor (1).

8. A safe and environmentally friendly nitration reaction system according to any one of claims 1 to 7, characterized in that: The temperature sensor (6) comprises at least a first temperature sensor (61) and a second temperature sensor (62); The first temperature sensor (61) is arranged at the nitric acid inlet of the microchannel reactor (1), and the second temperature sensor (62) is arranged at the nitric acid inlet of the dynamic tubular reactor (2).

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