An aniline refining system
By combining dehydration and distillation mechanisms, multiple purification processes for aniline were achieved, solving the problem of poor aniline refining effect in existing technologies, improving the refining effect and reducing energy consumption.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CHONGQING CHANGFENG CHEM IND
- Filing Date
- 2025-08-28
- Publication Date
- 2026-05-26
Smart Images
Figure CN224270190U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of aniline production, and in particular to an aniline refining system. Background Technology
[0002] Aniline is an important organic chemical raw material and fine chemical intermediate. Up to 300 major products can be derived from aniline, including those used in plastics, fragrances, clothing, pharmaceuticals, and rubber accelerators. It is a key raw material for antioxidants, and is also used as a stabilizer in explosives, an anti-knock agent in gasoline, and a solvent. Pure aniline can be obtained by refining crude aniline.
[0003] The refining process of crude aniline is entirely physical. Water, nitrobenzene, tar, and other impurities are removed from the crude aniline through distillation to obtain the final aniline product. Liquids all have the ability to evaporate into vapor, but the volatility varies among different liquids. Volatility is usually used to express the vapor pressure of a pure substance at a given temperature. Conventionally, the more volatile component in a mixture is called the light component, and the less volatile component is called the heavy component. Distillation utilizes the different volatility of the components in a mixture—that is, the different vapor pressures of the components at the same temperature—to transfer the light component from the liquid phase to the gas phase, while the heavy component from the gas phase transfers to the liquid phase, thus achieving separation. Many existing aniline refining systems have relatively simple processes when refining crude aniline, resulting in poor refining efficiency. Utility Model Content
[0004] The present invention aims to provide an aniline refining system that can perform multiple impurity removal and purification processes on crude aniline, thereby improving the refining effect of aniline and reducing energy consumption.
[0005] Therefore, the technical solution adopted by this utility model is as follows: an aniline refining system, including a dehydration mechanism and a distillation mechanism. The dehydration mechanism includes a crude aniline tank. The discharge pipe of the crude aniline tank is connected to the cold-side inlet of the first condenser of the distillation column via a dehydration tower feed pump, a dehydration flow meter, and a dehydration regulating valve group. The cold-side outlet of the first condenser of the distillation column is connected to the feed inlet at the top of the aniline dehydration tower. The discharge outlet at the top of the aniline dehydration tower is connected to the first condenser of the dehydration tower. The condensate outlet of the first condenser of the dehydration tower is connected to the second condenser of the dehydration tower. The outlet of the second condenser of the dehydration tower is connected to the aniline water vapor stripping system. The upper liquid inlet of the column is connected to the aniline water stripping column, and the middle part of the column is filled with packing material. A nitrogen inlet pipeline is installed below the packing material. The bottom aniline water outlet pipeline of the aniline water stripping column is connected to the aniline water re-separator. The distillation mechanism includes an aniline distillation column. The bottom material outlet pipeline of the aniline dehydration column is connected to the lower inlet of the aniline distillation column. The top distillate outlet pipeline of the aniline distillation column is connected to the hot side inlet of the first condenser of the distillation column. The hot side outlet of the first condenser of the distillation column is connected in sequence to the second condenser of the distillation column, the third condenser of the distillation column, the aniline product cooler, and the aniline reflux tank.
[0006] As a preferred embodiment of the above scheme, the aniline reflux tank is equipped with a collection pipeline, the collection pipeline is connected to a conveying regulating valve group and an intermediate aniline product tank, and the outlet pipeline of the intermediate aniline product tank is connected to an aniline product conveying pump.
[0007] More preferably, the aniline reflux tank is provided with a reflux pipeline connected to the reflux port of the aniline distillation column, and the reflux pipeline is provided with an aniline reflux pump, a reflux flow meter and a reflux regulating valve group.
[0008] More preferably, a dehydration tower reboiler is provided at the bottom of the aniline dehydration tower.
[0009] More preferably, a rotor flow meter and a gas supply regulating valve group are installed on the nitrogen inlet pipeline of the aniline water stripping tower.
[0010] More preferably, the tail gas outlet at the top of the aniline water stripping tower is connected to a tail gas VOC treatment system.
[0011] More preferably, the bottom residue discharge line of the aniline distillation column is connected to the residue distillation pot, the top gas outlet line of the residue distillation pot is connected to the residue distillation condenser, the residue distillation condenser is connected to the residue tank, and the residue tank is connected to the crude aniline tank.
[0012] The beneficial effects of this utility model are:
[0013] 1. The use of dehydration and distillation mechanisms allows for multiple purification processes to remove impurities from crude aniline, improving the refining effect of the finished aniline.
[0014] 2. The crude aniline exchanges heat with the gas phase at the top outlet of the aniline distillation column in the first condenser of the distillation column, which can avoid the need for additional preheating of the crude aniline and reduce energy consumption.
[0015] 3. This utility model uses pipes and pumps to add materials, which improves the efficiency of material addition and avoids harm to workers caused by harmful materials. Attached Figure Description
[0016] Figure 1 This is a process flow diagram of this utility model.
[0017] Figure 2 yes Figure 1 A schematic diagram of the structure of the aniline water stripping tower.
[0018] Figure 3 yes Figure 1 A schematic diagram of the structure of the aniline dehydration tower.
[0019] Figure 4 yes Figure 1 A schematic diagram of the structure of a aniline distillation column. Detailed Implementation
[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments.
[0021] like Figure 1-4 As shown, an aniline refining system includes a dehydration mechanism and a distillation mechanism. The dehydration mechanism includes a crude aniline tank 1. The discharge pipe of the crude aniline tank 1 is connected to the cold-side inlet of the first condenser 5 of the distillation column via a dehydration tower feed pump 2, a dehydration flow meter 3, and a dehydration regulating valve group 4. The cold-side outlet of the first condenser 5 is connected to the feed inlet at the top of the aniline dehydration tower 6. The discharge outlet at the top of the aniline dehydration tower 6 is connected to the first condenser 7 of the dehydration tower. The condensate outlet of the first condenser 7 is connected to the second condenser 8 of the dehydration tower. The outlet of the second condenser 8 is connected to the upper liquid inlet of the aniline water stripping tower 9. The middle part of the aniline water stripping tower 9 is filled with packing material, and a nitrogen inlet pipeline is installed below the packing material. The bottom aniline water outlet pipeline of the aniline water stripping tower 9 is connected to an aniline water re-separator 18. The distillation unit includes an aniline distillation column 13. The bottom material discharge line of the aniline dehydration column 6 is connected to the lower feed inlet of the aniline distillation column 13. The top distillate outlet line of the aniline distillation column 13 is connected to the hot side inlet of the first condenser 5 of the distillation column. The hot side outlet of the first condenser 5 of the distillation column is sequentially connected to the second condenser 22, the third condenser 23, the aniline product cooler 24, and the aniline reflux tank 25.
[0022] During refining, the crude aniline from crude aniline tank 1 is first pumped by dehydration tower feed pump 2. The feed flow rate is adjusted to 1000-10000 kg / h via dehydration flow meter 3 and dehydration regulating valve group 4. Then, it enters the first condenser 5 of the distillation tower for heat exchange with the vapor phase at the top outlet of aniline distillation tower 13. The preheated crude aniline then enters aniline dehydration tower 6 (the structure of aniline dehydration tower 6 is existing technology, containing packing material with spray nozzles above and a bottom liquid storage section below). It undergoes gas-liquid contact with the rising steam in the bottom of aniline dehydration tower 6 to achieve separation. The vapor phase benzene, water, and aniline distilled from the top of aniline dehydration tower 6 are condensed through the tube layers of the first condenser 7 and the second condenser 8 before entering aniline water stripping tower 9. The first condenser 7 and the second condenser 8 are existing technologies, with condensate flowing through the shell layer. After the crude aniline, from which water has been removed from the bottom of aniline dehydration tower 6, is collected, it enters the bottom of aniline distillation tower 13. There, it is vaporized by steam heating in the reboiler of distillation tower 13, and then undergoes countercurrent gas-liquid contact separation with the aniline refluxed from the top of tower 13. The distillate from the top of aniline distillation tower 13 sequentially passes through the first condenser 5 (heat exchange with crude aniline), then through the second condenser 22, and finally through the third condenser 23 (heat exchange with circulating water) for condensation. It then enters the aniline product cooler 24 for further cooling to 30–60°C with circulating water, yielding refined aniline. The refined aniline then enters the aniline reflux tank 25. The aniline refining process is conducted under negative pressure.
[0023] The aniline reflux tank 25 is equipped with a collection pipeline, which is connected to the conveying regulating valve group 19 and the aniline finished product intermediate tank 21. The outlet pipeline of the aniline finished product intermediate tank 21 is connected to the aniline finished product conveying pump 17.
[0024] The liquid level of the aniline reflux tank 25 is controlled by the conveying regulating valve group 19, so that a portion of the refined aniline in the aniline reflux tank 25 enters the aniline finished product intermediate tank 21, and is then conveyed to the outside of the boundary area by the aniline finished product conveying pump 17.
[0025] The aniline reflux tank 25 is equipped with a reflux pipeline connected to the reflux port of the aniline distillation column 13. The reflux pipeline is equipped with an aniline reflux pump 26, a reflux flow meter 27, and a reflux regulating valve group 28.
[0026] Another portion of the refined aniline in the aniline reflux tank 25 is transported by the aniline reflux pump 26, and then the reflux flow rate is controlled to be below 2500 kg / h by the reflux flow meter 27 and the reflux regulating valve group 28, and then returned to the upper part of the aniline distillation column 13 as reflux liquid.
[0027] A dehydration tower reboiler 20 is installed at the bottom of the aniline dehydration tower 6.
[0028] Steam at 0.8 MPa enters the reboiler 20 of the dehydration tower. The heating steam pressure in the reboiler 20 is controlled between 0.2 and 0.8 MPa (G). The heat required for the evaporation of aniline water in the aniline dehydration tower 6 is provided by the heating steam from the reboiler 20. The bottom temperature of the aniline dehydration tower 6 is controlled between 120 and 145°C, the middle temperature between 85 and 140°C, and the top temperature between 60 and 135°C. The cooling medium for the first condenser 7 of the dehydration tower is circulating water, and the outlet temperature of the first condenser 7 is controlled below 85°C. The cooling medium for the second condenser 8 of the dehydration tower is 5°C chilled water, and the outlet pipe temperature of the second condenser 8 is controlled below 50°C.
[0029] A rotor flow meter 12 and a gas supply regulating valve group 11 are installed on the nitrogen inlet pipeline of the aniline water stripping tower 9. The tail gas outlet at the top of the aniline water stripping tower 9 is connected to a tail gas VOC treatment system 10.
[0030] Nitrogen gas flow is controlled between 0 and 30 Nm³ via rotor flow meter 12 and gas supply regulating valve group 11. 3 / h, then enters the aniline water stripping tower 9, where nitrogen stripping removes a small amount of benzene dissolved in the solution. The stripped aniline water then enters the aniline water re-separator 18, and the tail gas from the top of the tower enters the tail gas VOC treatment system 10.
[0031] The bottom residue discharge line of the aniline distillation column 13 is connected to the residue distillation pot 14. The top gas outlet line of the residue distillation pot 14 is connected to the residue distillation condenser 15. The residue distillation condenser 15 is connected to the residue tank 16. The residue tank 16 is connected to the crude aniline tank 1.
[0032] High-boiling-point material from the bottom of aniline distillation column 13 is periodically collected and processed in residual distillation pot 14. The residual liquid is heated by steam in a coil within residual distillation pot 14, maintaining the distillation temperature between 130 and 170°C. The aniline vaporizes and enters residual distillation condenser 15, where it is condensed to below 75°C. The condensate is collected in residual liquid tank 16 and then returned to crude aniline tank 1. High-boiling-point material in residual distillation pot 14 is collected in barrels and then outsourced for further processing. Both the distillation processes in aniline distillation column 13 and aniline residual distillation pot 14 are operated under vacuum conditions.
[0033] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.
Claims
1. An aniline refining system, characterized in that: The system includes a dehydration mechanism and a distillation mechanism. The dehydration mechanism includes a crude aniline tank (1). The discharge pipe of the crude aniline tank (1) is connected to the cold side inlet of the first condenser (5) of the distillation column via a dehydration tower feed pump (2), a dehydration flow meter (3), and a dehydration regulating valve group (4). The cold side outlet of the first condenser (5) of the distillation column is connected to the feed inlet at the top of the aniline dehydration tower (6). The discharge outlet at the top of the aniline dehydration tower (6) is connected to the first condenser (5) of the distillation column. The condenser (7) is connected to the first condenser (7) of the dehydration tower. The condensate outlet of the first condenser (7) of the dehydration tower is connected to the second condenser (8) of the dehydration tower. The outlet of the second condenser (8) of the dehydration tower is connected to the upper liquid inlet of the aniline water stripping tower (9). The middle part of the aniline water stripping tower (9) is filled with packing material. A nitrogen gas inlet pipeline is provided below the packing material. The bottom aniline water outlet pipeline of the aniline water stripping tower (9) is connected to the aniline water re-separator (18). The distillation unit includes an aniline distillation column (13); the bottom material discharge line of the aniline dehydration column (6) is connected to the lower feed inlet of the aniline distillation column (13), the top distillate outlet line of the aniline distillation column (13) is connected to the hot side inlet of the first condenser (5) of the distillation column, and the hot side outlet of the first condenser (5) of the distillation column is sequentially connected to the second condenser (22) of the distillation column, the third condenser (23) of the distillation column, the aniline product cooler (24), and the aniline reflux tank (25).
2. The aniline refining system according to claim 1, characterized in that: The aniline reflux tank (25) is equipped with a collection pipeline, and the collection pipeline is connected to a conveying regulating valve group (19) and an aniline finished product intermediate tank (21). The outlet pipeline of the aniline finished product intermediate tank (21) is connected to an aniline finished product conveying pump (17).
3. The aniline refining system according to claim 2, characterized in that: The aniline reflux tank (25) is equipped with a reflux pipeline connected to the reflux port of the aniline distillation column (13). The reflux pipeline is equipped with an aniline reflux pump (26), a reflux flow meter (27), and a reflux regulating valve group (28).
4. The aniline refining system according to claim 1, characterized in that: The bottom of the aniline dehydration tower (6) is equipped with a dehydration tower reboiler (20).
5. The aniline refining system according to claim 1, characterized in that: The nitrogen inlet pipeline of the aniline water stripping tower (9) is equipped with a rotor flow meter (12) and a gas supply regulating valve group (11).
6. The aniline refining system according to claim 1, characterized in that: The tail gas outlet at the top of the aniline water stripping tower (9) is connected to a tail gas VOC treatment system (10).
7. The aniline refining system according to claim 1, characterized in that: The bottom residue discharge line of the aniline distillation column (13) is connected to the residue distillation pot (14), the top gas outlet line of the residue distillation pot (14) is connected to the residue distillation condenser (15), the residue distillation condenser (15) is connected to the residue tank (16), and the residue tank (16) is connected to the crude aniline tank (1).