A quantitative feeding device for raw materials in the production of p-nitrobenzoic acid

Abstract

This utility model relates to the field of p-nitrobenzoic acid production technology, and in particular to a device for quantitatively dispensing raw materials for p-nitrobenzoic acid production. The device includes a mixed acid solution reactor, a nitration reactor, a staged cooling assembly, and a control mechanism. The mixed acid solution reactor is used to prepare a mixed acid solution of sulfuric acid and nitric acid. The nitration reactor is used to react the cooled mixed acid solution with toluene. The staged cooling assembly is connected between the output end of the mixed acid solution reactor and the input end of the nitration reactor, and is used to cool the mixed acid solution that needs to be quantitatively added to the nitration reactor. The control mechanism includes a controller and a temperature sensor. This utility model uses the staged cooling assembly to cool the mixed acid solution that needs to be quantitatively added to the nitration reactor in small batches, effectively avoiding the problem of cooling lag caused by large quantities of mixed acid solution and long cooling paths, and ensuring the temperature uniformity of the mixed acid solution.

Description

Technical Field

[0001] This utility model relates to the field of p-nitrobenzoic acid production technology, and in particular to a raw material quantitative feeding device for p-nitrobenzoic acid production. Background Technology

[0002] In the production process of p-nitrobenzoic acid, sulfuric acid is first added to nitric acid to form a mixed acid solution. Then, the mixed acid solution is gradually and quantitatively added to toluene to produce a nitration reaction. However, the mixed acid solution will generate a high temperature when it is prepared. Before adding toluene, the temperature of the mixed acid solution needs to be reduced to below 30°C. This is because a nitration reaction will occur when mixed with toluene, and the nitration reaction is a strongly exothermic reaction. If the temperature of the mixed acid solution itself is high, it is highly dangerous when it reacts with toluene. Therefore, the mixed acid solution needs to be cooled before quantitative feeding.

[0003] Currently, when cooling mixed acid solutions, the common method is to install a cooling jacket on the outside of the mixed acid solution reactor for cooling, followed by timed and quantitative feeding. However, the cooling device first cools the mixed acid solution that is in contact with the inner wall of the reactor. The mixed acid solution located in the center of the reactor, being far from the cooling device, may not reach the cooling standard within a certain time and will be discharged into the toluene. This may have a certain impact on the mixing and reaction with toluene, or it may be necessary to wait for the mixed acid solution to be completely cooled to the set level before it can be added to the toluene, affecting the timed and quantitative feeding requirements.

[0004] Based on the above situation, it is necessary to design a quantitative feeding device for the production of p-nitrobenzoic acid to solve the above problems. Utility Model Content

[0005] This invention provides a quantitative feeding device for raw materials used in the production of p-nitrobenzoic acid, in order to solve the problems existing in the prior art.

[0006] The technical problem solved by this utility model is achieved by the following technical solution:

[0007] A device for quantitatively dispensing raw materials for the production of p-nitrobenzoic acid includes a mixed acid solution reactor, a nitration reactor, a staged cooling assembly, and a control mechanism. The mixed acid solution reactor is used to prepare a mixed acid solution of sulfuric acid and nitric acid. The nitration reactor is used to react the cooled mixed acid solution with toluene. The staged cooling assembly is connected between the output end of the mixed acid solution reactor and the input end of the nitration reactor to cool the mixed acid solution to be quantitatively added into the nitration reactor. The control mechanism includes a controller and a temperature sensor. The temperature sensor is mounted on the staged cooling assembly to detect the temperature of the mixed acid solution to be quantitatively added into the nitration reactor. The controller receives the temperature signal from the temperature sensor and controls the staged cooling assembly to discharge the mixed acid solution into the nitration reactor.

[0008] Preferably, the staged cooling assembly includes multiple staged cooling tanks, the sum of the capacities of the multiple staged cooling tanks is the amount to be quantitatively added into the nitration reactor, and each of the multiple staged cooling tanks is provided with a cooling mechanism on its outer side.

[0009] Preferably, the staged cooling assembly includes multiple staged cooling tanks, each staged cooling tank holding the amount to be quantitatively added into the nitration reactor, and each of the multiple staged cooling tanks is provided with a cooling mechanism on its outer side.

[0010] Preferably, the input ends of the plurality of staged cooling tanks are connected to the output end of the mixed acid solution reactor via an input main pipe, and the output ends of the plurality of staged cooling tanks are connected to the input end of the nitration reactor via an output main pipe. The input main pipe is provided with a first control valve, and the output main pipe is provided with a second control valve.

[0011] Preferably, the input ends of the plurality of staged cooling tanks are all connected to the mixed acid solution reactor through input branch pipes, and the output ends of the plurality of staged cooling tanks are all connected to the nitration reactor through output branch pipes. Each input branch pipe is provided with a first control valve, and each output branch pipe is provided with a second control valve.

[0012] Preferably, it also includes a timer, which works in conjunction with the controller and temperature sensor. When a preset time is reached and the temperature of the mixed acid solution drops to a set value, the controller controls the staged cooling component to discharge the staged cooling mixed acid solution into the nitration reactor.

[0013] The beneficial effects of this invention are as follows: by using a staged cooling component to cool the mixed acid solution that needs to be quantitatively added to the nitration reactor, the cooling is carried out in small batches, which effectively avoids the problem of cooling lag caused by large volume of mixed acid solution and long cooling path, ensuring the temperature uniformity of the mixed acid solution, providing stable raw material conditions for subsequent nitration reaction, and when the temperature reaches the set threshold, it can be directly discharged into the nitration reactor without waiting for the entire batch of solution to cool uniformly, reducing unnecessary waiting time and improving efficiency. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0015] Figure 1 Schematic diagram of the isometric structure provided by this utility model Figure 1 ;

[0016] Figure 2 Schematic diagram of the isometric structure provided by this utility model Figure 2 ;

[0017] Figure 3 A schematic diagram of the structure of the first embodiment of this utility model;

[0018] Figure 4 This is a schematic diagram of the structure of the second embodiment provided by this utility model;

[0019] Figure 5 This is the control diagram of this utility model.

[0020] In the diagram, 1 is a mixed acid solution reactor; 11 is a timer; 2 is a nitration reactor; 3 is a staged cooling assembly; 31 is a staged cooling tank; 32 is a cooling mechanism; 4 is a controller; 5 is a temperature sensor; 6 is an input main pipe; 61 is a first control valve; 7 is an output main pipe; 71 is a second control valve; 8 is an input branch pipe; and 9 is an output branch pipe. Detailed Implementation

[0021] To make the technical means, creative features, objectives and effects of this utility model easier to understand, the present utility model will be further described below with reference to specific illustrations.

[0022] Reference Figures 1-5As shown, a device for quantitatively dispensing raw materials for the production of p-nitrobenzoic acid includes a mixed acid solution reactor 1 for preparing a mixed acid solution of sulfuric acid and nitric acid, and a nitration reactor 2 for reacting the cooled mixed acid solution with toluene. A staged cooling assembly 3 is connected between the output end of the mixed acid solution reactor 1 and the input end of the nitration reactor 2 to cool the mixed acid solution to be quantitatively added to the nitration reactor 2. The mixed acid solution reacted in the mixed acid solution reactor 1 is discharged into the staged cooling assembly 3. Since the staged cooling assembly 3 holds a fixed amount of mixed acid solution, which is the amount to be added to the nitration reactor 2, the cooling efficiency is higher than that of directly cooling in the mixed acid solution reactor 1, and the phenomenon of uneven cooling is reduced. Cooling is now performed in small batches, effectively avoiding the problem of delayed cooling caused by large quantities of mixed acid solution and long cooling paths. The system also includes a control mechanism, comprising a controller 4 and a temperature sensor 5 electrically connected to the controller 4. The temperature sensor 5, located on the staged cooling assembly 3, detects the temperature of the mixed acid solution that needs to be quantitatively introduced into the nitration reactor 2. The controller 4, upon receiving the temperature signal from the temperature sensor 5, controls the staged cooling assembly 3 to discharge the mixed acid solution into the nitration reactor 2. When the temperature sensor 5 detects that the mixed acid solution in the staged cooling assembly 3 has decreased to a set range, the controller 4 controls the quantitative discharge of the mixed acid solution into the nitration reactor 2, eliminating the need to wait for the entire batch of solution to cool uniformly, reducing unnecessary waiting time, and improving efficiency.

[0023] Reference Figure 3 As shown, this is the first embodiment of the present invention: the staged cooling assembly 3 includes multiple staged cooling tanks 31, the sum of the capacities of the multiple staged cooling tanks 31 being the amount to be quantitatively added to the nitration reactor 2, and each of the multiple staged cooling tanks 31 is provided with a cooling mechanism 32 on its outer side. The input ends of the multiple staged cooling tanks 31 are connected to the output end of the mixed acid solution reactor 1 through an input manifold 6, and the output ends of the multiple staged cooling tanks 31 are connected to the input end of the nitration reactor 2 through an output manifold 7. The input manifold 6 is provided with a first control valve 61, and the output manifold 7 is provided with a second control valve 71 to adjust the amount of solution to be added to the nitration reactor. Taking a 10-liter mixed acid solution in reactor 2 as an example, after the first control valve 61 is opened, the mixed acid solution enters multiple staged cooling tanks 31 and is then closed. This allows the 10-liter mixed acid solution to be evenly contained. Then, it is cooled by an externally installed cooling mechanism 32. Compared to cooling the entire batch of mixed acid solution in the mixed acid solution reactor 1, this method is more efficient. Each staged cooling tank 31 is equipped with a temperature sensor 5. When the mixed acid solution in each staged cooling tank 31 reaches the set threshold, the second control valve 71 is opened to allow the cooled mixed acid solution to directly enter the nitration reactor 2.

[0024] Reference Figure 4 As shown, this is the second embodiment provided by the present invention: the staged cooling component 3 includes multiple staged cooling tanks 31, each staged cooling tank 31 having a capacity equal to the amount to be quantitatively added to the nitration reactor 2, and each of the multiple staged cooling tanks 31 is provided with a cooling mechanism 32 on its outer side. Taking 10 liters of mixed acid solution to be added to the nitration reactor 2 as an example, the capacity of each staged cooling tank 31 can be set to 10 liters, or quantitative addition to each staged cooling tank 31 can be achieved through a flow meter, etc. The input ends of the multiple staged cooling tanks 31 are all connected to the mixed acid solution reactor 1 through input pipes 8, and the output ends of the multiple staged cooling tanks 31 are all connected to the nitration reactor 2 through output pipes 9, and each input pipe 8 is provided with a first control valve 61, and each output pipe 9 is provided with a second control valve 71. When the temperature sensor 5 detects a decrease in the temperature of a certain staged cooling tank 31... Once the set range is reached, the controller 4 controls the second control valve 71 on the corresponding output pipe 9 to output the mixed acid solution. Compared to the first embodiment where a fixed amount of mixed acid solution is separately packaged, this method packages a relatively large amount of mixed acid solution. Under the condition that the cooling efficiency of the cooling mechanism 32 is the same, the cooling time required is relatively long. In the first embodiment, since the fixed amount of mixed acid solution is divided into different staged cooling tanks 31, the capacity of each staged cooling tank 31 is small, and the cooling efficiency is faster. In the second embodiment, after the mixed acid solution in a certain staged cooling tank 31 is cooled to the set threshold and discharged, the mixed acid solution will be discharged into this staged cooling tank 31 again. If the mixed acid solution in this staged cooling tank 31 does not reach the required temperature in a short period of time, the mixed acid solution can be output through the other staged cooling tanks 31. That is, the other staged cooling tanks 31 can be used as backups, with a certain redundancy.

[0025] In both the first and second embodiments, the cooling mechanism 32 can be a cooling jacket installed on the outside of each staged cooling tank 31, which can achieve cooling by introducing coolant or a device such as a semiconductor cooling chip. The above is the prior art, which should be known to those skilled in the art, and is not the main innovation of this solution, so it will not be described in detail here.

[0026] Reference Figure 5 As shown, it further includes a timer 11. The timer 11 works in conjunction with the controller 4 and the temperature sensor 5. When the preset time is reached and the temperature of the mixed acid solution drops to the set value, the controller 4 controls the staged cooling component 3 to discharge the staged cooling mixed acid solution into the nitration reactor 2. When the time for adding the mixed acid solution is set by the timer 11, and when the time is reached and the temperature set value is within the set range, the controller 4 can control the mixed acid solution to enter the nitration reactor 2.

[0027] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A device for quantitatively dispensing raw materials for the production of p-nitrobenzoic acid, characterized in that, include; Mixed acid solution reactor (1), the mixed acid solution reactor (1) is used to prepare a mixed acid solution of sulfuric acid and nitric acid; Nitration reactor (2), which is used to react the cooled mixed acid solution with toluene; A staged cooling component (3) is connected between the output end of the mixed acid solution reactor (1) and the input end of the nitration reactor (2) to cool the mixed acid solution that needs to be quantitatively added into the nitration reactor (2). The control mechanism includes a controller (4) and a temperature sensor (5). The temperature sensor is installed on the staged cooling assembly (3) to detect the temperature of the mixed acid solution that needs to be quantitatively introduced into the nitration reactor (2). The controller (4) is used to receive the temperature signal from the temperature sensor (5) and then control the staged cooling assembly (3) to discharge the mixed acid solution into the nitration reactor (2).

2. The raw material quantitative dispensing device for the production of p-nitrobenzoic acid according to claim 1, characterized in that, The staged cooling component (3) includes multiple staged cooling tanks (31), the sum of the contents of the multiple staged cooling tanks (31) is the amount to be added into the nitration reactor (2), and each of the multiple staged cooling tanks (31) is provided with a cooling mechanism (32) on its outer side.

3. The device for quantitatively dispensing raw materials for the production of p-nitrobenzoic acid according to claim 1, characterized in that, The staged cooling component (3) includes multiple staged cooling tanks (31), each staged cooling tank (31) has a capacity of the amount to be added into the nitration reactor (2), and each of the multiple staged cooling tanks (31) is provided with a cooling mechanism (32) on its outer side.

4. The raw material quantitative dispensing device for the production of p-nitrobenzoic acid according to claim 2, characterized in that, The input ends of the multiple staged cooling tanks (31) are connected to the output end of the mixed acid solution reactor (1) through the input manifold (6), and the output ends of the multiple staged cooling tanks (31) are connected to the input end of the nitration reactor (2) through the output manifold (7). The input manifold (6) is equipped with a first control valve (61), and the output manifold (7) is equipped with a second control valve (71).

5. The raw material quantitative feeding device for the production of p-nitrobenzoic acid according to claim 3, characterized in that, The input ends of the multiple staged cooling tanks (31) are connected to the mixed acid solution reactor (1) through input branch pipes (8), and the output ends of the multiple staged cooling tanks (31) are connected to the nitration reactor (2) through output branch pipes (9). Each input branch pipe (8) is equipped with a first control valve (61), and each output branch pipe (9) is equipped with a second control valve (71).

6. The device for quantitatively dispensing raw materials for the production of p-nitrobenzoic acid according to claim 1, characterized in that, It also includes a timer (11), which works in conjunction with the controller (4) and the temperature sensor (5). When the preset time is reached and the temperature of the mixed acid solution drops to the set value, the controller (4) controls the staged cooling component (3) to discharge the staged cooling mixed acid solution into the nitration reactor (2).

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