A nitrobenzoic acid slurry continuous dilution device

Abstract

The utility model discloses a nitrobenzoic acid slurry continuous dilution device, which includes a tower body, a sieve plate, a water spray device, a cooling device and a feed pipe. Advantages: After the slurry enters from the upper part of the tower body through the feed pipe and passes through the multi-stage sieve plates and the cooling device in sequence downward to reach the bottom of the tower, it contacts with the dilution water sprayed upward from different parts of the tower body in reverse, forming a slurry convection reaction system, realizing step-by-step dilution. At the same time, the cooler is arranged inside the tower body to achieve the purpose of cooling the inside of the slurry, which can effectively enhance the cooling effect and improve the dilution efficiency. In the process of the slurry flowing downward, it can be diluted and cooled step by step, so that continuous feeding and continuous discharging can be achieved to achieve the purpose of continuous dilution, reduce the liquid holding capacity inside the tower body, further avoid the occurrence of temperature runaway caused by local high temperature, avoid the generation of by-products due to high temperature, and reduce the difficulty of subsequent treatment; and, there is no need to prepare multiple dilution pots, which can reduce equipment costs.

Description

Technical field:

[0001] The utility model relates to the technical field of nitrobenzoic acid production, in particular to a nitrobenzoic acid slurry continuous dilution device. Background technology:

[0002] 3,5-Dinitrobenzoic acid is obtained by nitrating benzoic acid. Specifically, sulfuric acid is added into a dry reaction pot, benzoic acid is added under stirring, the reaction pot is heated to 60°C, fuming nitric acid is added dropwise, and the addition is completed below 85°C; the reaction is carried out at 80-85°C for 1h, at 100°C for 0.5-1h, and then the temperature is raised to 135°C for 2h; the reaction is allowed to stand overnight to obtain thick nitrobenzoic acid, and 3,5-dinitrobenzoic acid and waste water are obtained after solid-liquid separation. In order to facilitate solid-liquid separation, the nitrobenzoic acid turbid liquid obtained by the reaction needs to be diluted with water. A large amount of heat will be released during the dilution process, so cooling treatment is required; the current dilution process is: S1, add 6000L of bottom water to the dilution pot, start stirring, and open the exhaust gas exhaust valve; S2, after the exhaust is normal, slowly pump a batch of nitrobenzoic acid slurry (1700-1800L) into the dilution pot with a pump, and pass circulating water into the jacket of the dilution pot for cooling. During the feeding process, the feeding hole should be covered to prevent nitrogen oxide gas from escaping; S3, after the material is added, continue stirring, open the frozen brine and slowly cool it down to below 28°C before discharging. The above-mentioned dilution process has the following problems: (1) The jacket cooling has limited heat exchange efficiency, which leads to a slow entire dilution process and a long dilution treatment time; (2) During the dilution process, local point addition and high local temperature are prone to produce other by-products, increasing the difficulty of subsequent treatment; (3) The dilution pot is diluted by batch addition. After a certain period of stirring and dilution, the liquid in the dilution pot is discharged before the next batch of nitrobenzoic acid slurry can be diluted. Continuous production cannot be achieved. Therefore, multiple dilution pots are required, and the equipment cost is high. Utility model content:

[0003] The utility model aims to provide a nitrobenzoic acid slurry continuous dilution device.

[0004] The utility model is implemented by the following technical scheme: a nitrobenzoic acid slurry continuous dilution device, which comprises a tower body, a sieve plate, a water spray device, a cooling device and a feed pipe, wherein an exhaust port is arranged on the top of the tower body, a discharge port is arranged on the bottom of the tower body, a feed pipe is arranged on the upper part of the tower body, and a feed end of the feed pipe is arranged on the outside of the tower body; a plurality of sieve plates are arranged at intervals inside the tower body below the feed pipe, the water spray device with a nozzle arranged upward is arranged inside the tower body above each sieve plate, and a plurality of cooling devices are arranged inside the tower body.

[0005] Furthermore, the cooling device includes a pipe box and a tube array. One of the pipe boxes is fixed to the outside of both sides of the tower body, and a plurality of transversely arranged tube arrays are provided inside the tower body between the two pipe boxes. Both ends of the tube arrays pass through the tower body and are connected to the corresponding pipe boxes. The two pipe boxes are connected with a water inlet pipe and a water outlet pipe respectively.

[0006] Furthermore, the cooling device is installed inside the tower body above each of the water spray devices.

[0007] Furthermore, a distributor is arranged inside the tower body at the outlet end of the feed pipe.

[0008] Furthermore, the distributor includes a distributor cover fixed to the inner wall of the tower body, a plurality of gas phase through holes and liquid phase through holes are arranged on the distributor cover, and the outlet end of the feed pipe is connected to the top of the liquid phase through hole.

[0009] Furthermore, a hopper is provided at the bottom end of the liquid phase through hole.

[0010] Furthermore, a vertical partition is fixed in the middle of the hopper, and two inclined guide plates are arranged at the bottom end of the hopper. The top end of the guide plate is fixed to the bottom end of the partition, and a material distribution channel is formed between the guide plate and the bottom end of the hopper.

[0011] Furthermore, a plurality of vertically arranged guide rods are fixed at intervals on the inner wall of the hopper.

[0012] Furthermore, a water spray device with a spray head arranged downward is provided inside the tower body above the feed pipe.

[0013] Furthermore, temperature detection ports are provided at the top, middle and bottom of the tower body.

[0014] The advantages of the utility model are as follows: the slurry enters from the upper part of the tower body through the feed pipe, passes through the multi-stage sieve plates and cooling devices in sequence downward to reach the bottom of the tower, and contacts with the dilution water sprayed upward from different parts of the tower body in reverse, forming a slurry-liquid convection reaction system, realizing step-by-step dilution. At the same time, the cooler is arranged inside the tower body to achieve the purpose of cooling the slurry from the inside, which can effectively enhance the cooling effect and improve the dilution efficiency. In the process of the slurry flowing downward, it can be diluted and cooled step by step, so that continuous feeding and continuous discharging can be achieved to achieve the purpose of continuous dilution, reduce the liquid holding capacity inside the tower body, further avoid the occurrence of temperature runaway caused by local high temperature, avoid the production of by-products by high temperature, and reduce the difficulty of subsequent treatment; and, there is no need to prepare multiple dilution pots, which can reduce equipment costs. Description of the drawings:

[0015] Figure 1It is a schematic diagram of the overall structure of the utility model.

[0016] Figure 2 This is a schematic diagram of the structure of the distributor.

[0017] Figure 3 A cross-sectional view of the distributor.

[0018] Figure 4 This is a structural diagram of the top water spray device.

[0019] Figure 5 This is the structural diagram of the water spray device in the middle.

[0020] Figure 6 This is the structural diagram of the water spray device at the bottom.

[0021] Tower body 1, exhaust port 11, discharge port 12, manhole 13, upper head 14, lower head 15, tower section 16, temperature detection port 17, sieve plate 2, water spray device 3, main nozzle 31, branch pipe 32, nozzle 33, central branch pipe 34, side branch pipe 35, cooling device 4, pipe box 41, tube array 42, water inlet pipe 43, water outlet pipe 44, feed pipe 5, distributor 6, distributor cover plate 61, gas phase through hole 62, liquid phase through hole 63, hopper 64, partition 65, guide plate 66, material distribution channel 67, guide rod 68. Specific implementation method:

[0022] In the description of the present invention, it should be noted that if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, if the terms "first", "second", "third" appear, they are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0023] like Figures 1 to 6As shown, a nitrobenzoic acid slurry continuous dilution device includes a tower body 1, a sieve plate 2, a water spray device 3, a cooling device 4 and a feed pipe 5. The feed pipe 5 is arranged at the upper part of the tower body 1, and a water spray device 3 with a nozzle 33 arranged downward is arranged inside the tower body 1 above the feed pipe 5. The water spray device 3 arranged at the top for spraying downward can be used to spray washing water downward, which is used to clean the materials adhered to the tower during the continuous dilution process. The feed end of the feed pipe 5 is arranged outside the tower body 1, and a distributor 6 is arranged inside the tower body 1 at the outlet end of the feed pipe 5, so that the slurry discharged from the feed pipe 5 is evenly distributed. Specifically, the distributor 6 includes a distributor cover plate 61 fixed to the inner wall of the tower body 1, and a plurality of gas phase through holes 62 and liquid phase through holes 63 are arranged on the distributor cover plate 61, and the outlet end of the feed pipe 5 is connected to the top of the liquid phase through hole 63. When diluting the slurry, the nitrogen oxides produced by the thermal decomposition of nitric acid flow upward through the gas phase through hole 62, and the slurry sent from the feed pipe 5 flows downward through the liquid phase through hole 63; by setting up the distributor 6, the gas phase and the liquid phase can be separated so that the two do not interfere with each other, thereby ensuring the stability of the reaction.

[0024] In addition, a hopper 64 is provided at the bottom end of the liquid phase through hole 63. The slurry enters the hopper 64 after being discharged from the feed pipe 5, and then is discharged downward through the bottom outlet of the hopper 64. A vertical partition 65 is fixed in the middle of the hopper 64, and two inclined guide plates 66 are provided at the bottom end of the hopper 64. The top of the guide plate 66 is fixed to the bottom end of the partition 65, and a distribution channel 67 is formed between the guide plate 66 and the bottom end of the hopper 64. After the slurry enters the hopper 64, it is diverted by the partition 65, and then discharged through the distribution channel 67 under the action of the guide plate 66, so that the slurry can be evenly distributed, which helps to enhance the slurry dilution effect. A number of vertically arranged guide rods 68 are fixed at intervals on the inner wall of the hopper 64. By setting the guide rods 68, on the one hand, the strength of the hopper 64 can be strengthened, and on the other hand, the interval setting can be used to break up the slurry and prevent the material from sticking.

[0025] Several sieve plates 2 are arranged at intervals inside the tower body 1 below the feed pipe 5, and a water spray device 3 with a nozzle 33 arranged upward is arranged inside the tower body 1 above each sieve plate 2; the slurry enters from the upper part of the tower body 1 through the feed pipe 5 and flows downward, and the dilution water sprayed by the water spray device 3 above the sieve plate 2 is sprayed upward, and the slurry and the dilution water form a slurry convection reaction system with good dilution effect. In addition, multiple water spray devices 3 for spraying dilution water are arranged in the tower body 1, which can realize step-by-step continuous dilution, enhance the mass transfer effect of dilution water and slurry, help to speed up the dilution reaction process, shorten the dilution treatment time, and improve production efficiency. The sieve plate 2 can intercept undiluted or agglomerated materials, and then flush them through the sieve plate 2 with dilution water to improve the dilution effect. Several cooling devices 4 are arranged inside the tower body 1, and the cooling device 4 is arranged inside the tower body 1 to achieve internal cooling and improve cooling efficiency. An exhaust port 11 is provided at the top of the tower body 1, and the gas generated during the dilution process is discharged from the exhaust port 11. A discharge port 12 is provided at the bottom of the tower body 1, and the diluted dilution liquid is discharged from the equipment through the discharge port 12. In addition, a manhole 13 is provided on the tower body 1 for easy maintenance.

[0026] Specifically, a cooling device 4 is installed inside the tower body 1 above each water spray device 3. The cooling device 4 includes a pipe box 41 and a tube array 42. A pipe box 41 is fixed to the outside of both sides of the tower body 1. A plurality of transversely arranged tube arrays 42 are arranged inside the tower body 1 between the two pipe boxes 41. The two ends of the tube array 42 pass through the tower body 1 and are connected to the corresponding pipe box 41. The two pipe boxes 41 are connected to the water inlet pipe 43 and the water outlet pipe 44. When the slurry flows downward, it directly contacts the transversely arranged tube arrays 42, so as to achieve the purpose of cooling from the inside of the slurry, improve the heat exchange efficiency, and avoid the phenomenon of other by-products produced by local high temperature, thereby reducing the difficulty of subsequent treatment.

[0027] In this embodiment, the tower body 1 includes an upper head 14, a lower head 15, and a plurality of tower sections 16 connected between the upper head 14 and the lower head 15; the sieve plate 2 is clamped between two adjacent tower sections 16, or between the lower head 15 and the tower section 16 above it; the sieve plate 2 and the tower section 16 / lower head 15 are connected and fixed with enamel clips, which are easy to disassemble and assemble and convenient for maintenance.

[0028] In this embodiment, the top water spray device 3 includes a main nozzle 31 and two branch pipes 32 connected to both sides of the middle of the main nozzle 31. The diameter of the main nozzle 31 is 80 mm, and the diameter of the branch pipe 32 is 50 mm. Two nozzles 33 are respectively installed at the bottom of the main nozzle 31 and the branch pipe 32, and the nozzles 33 on the main nozzle 31 and the branch pipe 32 are on the same circumference. The bottom water spray device 3 includes a main nozzle 31 with a diameter of 40 mm, and a nozzle 33 is installed at the top of the main nozzle 31 corresponding to the center of the tower body 1. The water spray device 3 in the middle includes a main nozzle 31 with a diameter of 126 mm, a central branch pipe 34 with a diameter of 80 mm and a side branch pipe 35 with a diameter of 50 mm. The central branch pipe 34 is connected to both sides of the middle of the main nozzle 31, and the side branch pipes 35 are connected to both sides of the main nozzle 31 on both sides of the central branch pipe 34. Nozzles 33 are installed at the center top of the main nozzle 31 and the outer end tops of the central branch pipe 34 and the side branch pipes 35.

[0029] Temperature detection ports 17 are provided at the top, middle and bottom of the tower body 1; in this embodiment, two temperature detection ports 17 are provided at the top of the tower body 1 for detecting the temperature of the tower top; one temperature detection port 17 is provided at the bottom of the tower body 1 for detecting the temperature of the diluted slurry at the bottom of the tower; three temperature detection ports 17, upper, middle and lower, are provided in the middle of the tower body 1 for detecting the temperature of each section in the tower, and step-type temperature control is realized in combination with each cooling device 4. As shown in this embodiment, three cooling devices 4 can be provided, and the three temperature detection ports 17 in the middle of the tower body 1 are respectively provided under the three cooling devices 4, so that a three-stage temperature control system can be realized. Temperature control: In the first stage, the process temperature corresponding to the temperature detection port 17 in the upper middle part of the tower body 1 is controlled to be 80-90°C by adjusting the water inlet temperature of the first cooling device 4 at the top, in order to decompose and drive out the nitric acid contained in the slurry; in the second stage, the process temperature corresponding to the temperature detection port 17 in the middle is controlled to be 50-60°C by adjusting the second cooling device 4 in the middle, in order to control the dilution process to be carried out at the temperature most conducive to the reaction; in the third stage, the process temperature corresponding to the temperature detection port 17 in the lower part is controlled to be 25-30°C by the third cooling device 4 at the bottom, in order to control the centrifugal temperature of the diluted liquid.

[0030] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.

Claims

1. A nitrobenzoic acid slurry continuous dilution device, characterized in that: It includes a tower body, a sieve plate, a water spray device, a cooling device and a feed pipe. An exhaust port is arranged on the top of the tower body, a discharge port is arranged on the bottom of the tower body, the feed pipe is arranged on the upper part of the tower body, and the feed end of the feed pipe is arranged on the outside of the tower body; a plurality of the sieve plates are arranged at intervals inside the tower body below the feed pipe, a water spray device with a nozzle arranged upward is arranged inside the tower body above each of the sieve plates, and a plurality of the cooling devices are arranged inside the tower body.

2. The nitrobenzoic acid slurry continuous dilution device according to claim 1, characterized in that: The cooling device includes a pipe box and a tube array. A pipe box is fixed to the outside of both sides of the tower body respectively. A plurality of transversely arranged tube arrays are arranged inside the tower body between the two pipe boxes. Both ends of the tube arrays pass through the tower body and are connected to the corresponding pipe boxes respectively. A water inlet pipe and a water outlet pipe are connected to the two pipe boxes respectively.

3. The nitrobenzoic acid slurry continuous dilution device according to claim 1, characterized in that: The cooling device is installed inside the tower body above each of the water spray devices.

4. The nitrobenzoic acid slurry continuous dilution device according to claim 1, characterized in that: A distributor is arranged inside the tower body at the outlet end of the feed pipe.

5. A nitrobenzoic acid slurry continuous dilution device according to claim 4, characterized in that: The distributor comprises a distributor cover plate fixed to the inner wall of the tower body, a plurality of gas phase through holes and liquid phase through holes are arranged on the distributor cover plate, and the outlet end of the feed pipe is communicated with the top end of the liquid phase through hole.

6. The nitrobenzoic acid slurry continuous dilution device according to claim 5, characterized in that: A hopper is arranged at the bottom end of the liquid phase through hole.

7. The nitrobenzoic acid slurry continuous dilution device according to claim 6, characterized in that: A vertical partition is fixed in the middle of the hopper, and two inclined guide plates are arranged at the bottom of the hopper. The top of the guide plate is fixed to the bottom of the partition, and a material distribution channel is formed between the guide plate and the bottom of the hopper.

8. The nitrobenzoic acid slurry continuous dilution device according to claim 6, characterized in that: A plurality of vertically arranged guide rods are fixed at intervals on the inner wall of the hopper.

9. The nitrobenzoic acid slurry continuous dilution device according to claim 1, characterized in that: The water spraying device with a spray head arranged downward is arranged inside the tower body above the feed pipe.

10. The nitrobenzoic acid slurry continuous dilution device according to claim 1, characterized in that: Temperature detection ports are arranged at the top, middle and bottom of the tower body.

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