An apparatus for continuously producing 2,5-dichloroaniline

Abstract

The technical scheme discloses a device for continuously preparing 2,5-dichloroaniline, which comprises a first mixer, a first fixed bed reactor, a first separator, a second mixer, a second fixed bed reactor and a second separator; the first mixer comprises a cover plate, a gland, a mixing head and a mixing shell; the mixing shell is fixed on the first fixed bed reactor and communicates with the inner cavity of the first fixed bed reactor; the inner cavity of the mixing shell is sequentially provided with the gland and the mixing head from top to bottom; the cover plate is fixed above the gland and seals the joint of the cover plate and the mixing shell; the mixing head is internally provided with multiple transverse and longitudinal channels; the longitudinal channels are in communication with the feed inlet of the cover plate; and the transverse channels are in communication with the channels of the mixing shell. The technical scheme can solve the technical problem of how to ensure the safe access of hydrogen and the sealing safety while reducing the cost.

Description

Technical Field

[0001] This utility model relates to a chemical apparatus, specifically an apparatus for the continuous preparation of 2,5-dichloroaniline. Background Technology

[0002] 2,5-Dichloroaniline is a white to pale yellow crystalline powder, slightly soluble in water, and soluble in most organic solvents. The market development trend of the 2,5-dichloroaniline industry is generally good, with a large market supply, stable prices, and fierce market competition. The large market supply is due to the rise of major enterprises across the country, whose large-scale production of 2,5-dichloroaniline not only meets domestic market demand but also generates a certain amount for export. Therefore, developing a continuous catalytic hydrogenation process for 2,5-dichloroaniline has broad market prospects.

[0003] Currently, the main domestic production process for 2,5-dichloroaniline is batch-type catalytic hydrogenation, which has the following drawbacks: 1. Risk of hydrogen leakage and explosion: Hydrogen is a flammable and explosive gas. During batch hydrogenation, if the equipment is not properly sealed or the operation is improper, hydrogen leakage may occur. When exposed to open flames or high temperatures, it can easily cause fires or explosions; 2. High cost, low yield, large amount of waste generated, and serious pollution. Utility Model Content

[0004] The purpose of this invention is to provide an apparatus for the continuous preparation of 2,5-dichloroaniline. The technical problem to be solved is how to ensure the safe access of hydrogen and the sealing safety, while reducing costs.

[0005] An apparatus for the continuous preparation of 2,5-dichloroaniline includes a first mixer, a first fixed-bed reactor, a first separator, a second mixer, a second fixed-bed reactor, and a second separator;

[0006] The first mixer includes a cover plate, a pressure cap, a mixing head, and a mixing shell. The mixing shell is fixed on the first fixed bed reactor and communicates with the inner cavity of the first fixed bed reactor. The pressure cap and the mixing head are placed sequentially from top to bottom in the inner cavity of the mixing shell. The cover plate is fixed above the pressure cap and seals the joint between the cover plate and the mixing shell. The mixing head has multiple transverse and longitudinal channels inside. The longitudinal channel communicates with the feed inlet of the cover plate, and the transverse channel communicates with the channel of the mixing shell.

[0007] The first separator is connected between the first fixed-bed reactor and the second mixer;

[0008] The second mixer has the same structure as the first mixer and is installed on the second fixed-bed reactor. The inner cavity of the second mixer is in communication with the inner cavity of the second fixed-bed reactor.

[0009] The second separator is connected to the outlet of the second fixed-bed reactor.

[0010] The overall structure of the pressure cap is a cone with flat top and bottom.

[0011] The mixing head is a cylindrical structure with grooves on its sides.

[0012] The discharge port of the first separator is also connected to a preheater, the discharge port of which is connected to the inlet of the cover plate of the first mixer.

[0013] There is also a pressure ring between the cap and the mixing head, which is a cylindrical structure with an X-shaped longitudinal section.

[0014] The beneficial effects of this invention are: by designing the first mixer and the second mixer, the raw materials such as hydrogen and 2,5-dichloronitrobenzene can be well mixed and thus react fully. At the same time, the two mixers use internally designed pressure caps and mixing heads to ensure the gas sealing requirements for gas entering the fixed bed reactor. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of an apparatus for the continuous preparation of 2,5-dichloroaniline;

[0016] Figure 2 This is a schematic diagram of the combination of a mixer and a fixed-bed reactor;

[0017] Figure 3 This is an exploded cross-sectional view of the mixer;

[0018] In the picture

[0019] 1. First mixer; 11. Cover plate; 12. Pressure cap; 13. Mixing head; 131. Channel; 132. Groove; 14. Mixing shell; 15. Pressure ring;

[0020] 2. First fixed-bed reactor;

[0021] 3. First separator;

[0022] 4. Second mixer;

[0023] 5. Second fixed-bed reactor;

[0024] 6. Second separator;

[0025] 7. Preheater;

[0026] 81. Feed inlet; 82. Discharge outlet; Detailed Implementation

[0027] Please refer to Figures 1 to 3The diagram shows an apparatus for the continuous preparation of 2,5-dichloroaniline, mainly designed with a first mixer 1, a first fixed-bed reactor 2, a first separator 3, a second mixer 4, a second fixed-bed reactor 5, and a second separator 6. Additional components such as a cooler and a preheater 7 can be added as needed. The mixers are used for mixing materials, the fixed-bed reactors are used for reacting the mixed materials, the separators are used for separating the reacted materials, and the cooler and preheater 7 are used for cooling and preheating the reactants. In practical applications, other components can be added to improve the overall practicality of the equipment. In this case, the raw material liquid 2,5-dichloronitrobenzene and the solvent ethanol are prepared into a raw material liquid according to a set ratio, and then combined with raw material hydrogen gas under the action of a noble metal catalyst for hydrogenation reduction to 2,5-dichloroaniline.

[0028] As shown in the diagram, each container is first purged with nitrogen. The raw material 2,5-dichloronitrobenzene and the solvent ethanol are first pumped into the inlet 81 of the first mixer 1 (the inlet 81 at the cover plate 11) to form a mixture. Then, hydrogen is introduced into another inlet 81 of the first mixer 1 (the inlet 81 at the mixing head 13), allowing both the hydrogen and the mixture to enter the first fixed-bed reactor 2. The first fixed-bed reactor 2 then utilizes an internal noble metal catalyst to catalyze the reaction between the hydrogen and the mixture. Please refer to [reference needed]. Figure 2 and Figure 3 The first mixer 1 in the figure is designed with components such as a cover plate 11, a pressure cap 12, a mixing head 13, and a mixing shell 14. External pipes are sealed to the cover plate 11 and the mixing shell 14 via corresponding connectors, thus allowing material to enter. The cover plate 11 in the figure has a flange-like structure with mounting holes on both sides, facilitating installation on a fixed platform, and a feed inlet 81 in the middle. The pressure cap 12 is a conical structure with flat bottoms, primarily used for sealing the connection between the cover plate 11 and the mixing shell 14. To improve the sealing effect, a pressure ring 15 is added below the pressure cap 12. Its overall structure is a cylindrical structure with an X-shaped longitudinal section, thus creating a double-seal effect. The mixing head 13 in the figure is a cylindrical structure with transverse and longitudinal channels 131 inside to facilitate the flow of various raw materials. For example, the transverse channel 131 facilitates the flow of gas, while the longitudinal channel 131 is used for the flow of the raw material 2,5-dichloronitrobenzene and the solvent ethanol. To increase the gas flow rate, the transverse position of the mixing head 13 can be designed with a groove 132 structure corresponding to the feed port 81 on the side wall of the mixing shell 14. The mixing shell 14 in the figure is a hollow structure with an open top. Its outer side wall has a feed port 81 that penetrates the inner cavity. This feed port 81 is assembled with a hydrogen pipeline through a connector.

[0029] The first fixed-bed reactor 2 in the figure is an existing structure with an internal spiral guide plate designed to continuously increase the contact area between various materials, thereby improving reaction efficiency. The outlet 82 of the first fixed-bed reactor 2 discharges some unreacted raw materials and reactants; these substances then enter the first separator 3 for separation and recovery. Part of the raw materials are recovered, such as hydrogen and solvent, for reuse. The remaining raw materials and reactants are introduced into the second mixer 4 for further mixing with hydrogen before being introduced into the second fixed-bed reactor 5 for further reaction. As shown in the figure, a preheater 7 is installed at the outlet 82 of the first separator 3, which first separates the remaining hydrogen after the reaction through gas-liquid separation, then pressurizes it and reuses it at the inlet 81 of the first mixer 1. Solvent recovery involves separating, purifying, and recovering the ethanol from the hydrogenation reaction, sending it to the batching unit for recycling.

[0030] In practical applications, the first fixed-bed reactor 2 can remove part of the reaction heat by circulating part of the effluent. The outlet hot spot temperature of both the first fixed-bed reactor 2 and the second fixed-bed reactor 5 can be controlled by controlling the circulation ratio. Furthermore, by controlling the hydrogen flow rate into the first fixed-bed reactor 2, the feed conversion rate within it can be controlled. Simultaneously, a slight excess of hydrogen is provided in the second fixed-bed reactor 5 to ensure complete feed conversion.

[0031] The structures of the second mixer 4 and the second fixed-bed reactor 5 are the same as those of the first mixer 1 and the first fixed-bed reactor 2. The structure, function, and relationship to the material introduction of the second mixer 4 can be found in the above description. After the reaction in the second fixed-bed reactor 5, the reacted material is introduced from the outlet 82 into the second separator 6 for material separation, i.e., distillation and purification. This removes moisture and heavy tar components, yielding a final product that meets quality requirements.

[0032] The specific embodiments described above are merely illustrative of the present technical solution and are not intended to limit the present technical solution. In the description of the present technical solution, it should be noted that terms such as "upper" and "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are only for the convenience of describing the present technical solution and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present technical solution.

[0033] Furthermore, in the description of this technical solution, it should be noted that, unless otherwise explicitly specified and limited, the terms "fixed" and "fitting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this technical solution according to the specific circumstances.

[0034] Although embodiments of the present technical solution have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present technical solution, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An apparatus for the continuous preparation of 2,5-dichloroaniline, characterized in that: The reactor comprises a first mixer (1), a first fixed-bed reactor (2), a first separator (3), a second mixer (4), a second fixed-bed reactor (5), and a second separator (6). The first mixer (1) includes a cover plate (11), a pressure cap (12), a mixing head (13), and a mixing shell (14). The mixing shell (14) is fixed on the first fixed-bed reactor (2) and communicates with the inner cavity of the first fixed-bed reactor (2). The pressure cap (12) and the mixing head (13) are placed sequentially from top to bottom in the inner cavity of the mixing shell (14). The cover plate (11) is fixed above the pressure cap (12) and seals the joint between the cover plate (11) and the mixing shell (14). The mixing head (13) has multiple transverse and longitudinal channels (131) inside, wherein the longitudinal channel (131) is connected to the feed inlet (81) of the cover plate (11), and the transverse channel (131) is connected to the channel (131) of the mixing shell (14); the first separator (3) is connected between the first fixed bed reactor (2) and the second mixer (4); the structure of the second mixer (4) is the same as that of the first mixer (1) and is installed on the second fixed bed reactor (5), and the inner cavity of the second mixer (4) is connected to the inner cavity of the second fixed bed reactor (5); the second separator (6) is connected to the discharge port (82) of the second fixed bed reactor (5).

2. The apparatus for continuous preparation of 2,5-dichloroaniline according to claim 1, characterized in that: The cap (12) is a cone structure with flat bottoms on both sides.

3. The apparatus for continuous preparation of 2,5-dichloroaniline according to claim 2, characterized in that: The mixing head (13) is a cylindrical structure with grooves (132) on its side.

4. The apparatus for continuous preparation of 2,5-dichloroaniline according to claim 3, characterized in that: The discharge port (82) of the first separator (3) is also connected to a preheater (7), the discharge port (82) of which is connected to the inlet (81) of the cover plate (11) of the first mixer.

5. The apparatus for continuous preparation of 2,5-dichloroaniline according to claim 4, characterized in that: There is also a pressure ring (15) between the pressure cap (12) and the mixing head (13), which is a cylindrical structure with an X-shaped longitudinal section.

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