Safe feeding system of solid-liquid two-phase reaction kettle in chemical production
By combining multi-stage purification and preheating, the problems of hydrogen impurities and temperature control were solved, enabling safe and reliable production of aniline via the hydrogenation of nitrobenzene, and ensuring the stability of reactor temperature and product quality.
Patent Information
- Application Number
- CN202520202883.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-10
- Publication Date
- 2026-02-03
- Estimated Expiration
- 2035-02-10
AI Technical Summary
In the chemical production process of nitrobenzene hydrogenation to aniline, if impurities in the hydrogen are not completely removed and the hydrogen is not preheated, it can lead to catalyst poisoning, equipment blockage, unstable reaction, and failure of temperature control, which may cause safety accidents and affect production efficiency and product quality.
Multi-stage filtration and impurity removal are carried out using membrane filters, activated carbon adsorption towers, and dehydration towers. Hydrogen is preheated using a preheater, and a high-level coolant storage tank and temperature control jacket are installed outside the reactor to construct a dual-mode cooling mechanism to ensure reactor temperature control.
It effectively removes hydrogen impurities, improves reaction efficiency and product quality, ensures stable reactor temperature, avoids safety accidents, and guarantees safe and stable production.
Smart Images
Figure CN223861805U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of aniline production technology by hydrogenation of nitrobenzene, specifically a safe feeding system for a solid-liquid two-phase reactor in chemical production. Background Technology
[0002] The hydrogenation of nitrobenzene to aniline is an important chemical production process. Aniline, as a key organic chemical raw material, has wide applications in many fields such as dyes, pharmaceuticals, and rubber additives. In the hydrogenation reaction of nitrobenzene to aniline, hydrogen gas acts as a reducing agent, reacting with nitrobenzene to produce aniline. This reaction is usually carried out in a reaction vessel and is a solid-liquid two-phase reaction.
[0003] The hydrogen feed process suffers from incomplete impurity removal and lack of preheating. On one hand, the hydrogen may carry impurities such as sulfides and dust. Sulfides can poison the catalyst used in the reaction, reducing its activity and selectivity, leading to a decrease in the reaction rate. This prevents nitrobenzene from being fully converted to aniline, reducing product yield and potentially generating more byproducts, affecting the purity and quality of aniline. Solid impurities such as dust can clog pipelines and valves in the reaction equipment, affecting normal material transport and even causing equipment failure, increasing maintenance costs and downtime, thus reducing production efficiency. On the other hand, unpreheated hydrogen entering the reactor absorbs heat to raise its own temperature. This not only affects the temperature stability within the reactor, causing temperature fluctuations and hindering stable reaction progress, but also prolongs the time required to reach the optimal reaction temperature, reducing the initial reaction rate and extending the entire production cycle, thus reducing production efficiency. Furthermore, during production, a sudden power outage cannot immediately terminate the entire reaction. Because the reaction inside the reactor is exothermic, it will continue and release heat if it cannot be stopped in time. However, if the power supply is interrupted, the existing temperature control system (such as the refrigeration unit and other electrically powered equipment) will malfunction and fail to effectively remove the heat generated by the reaction, causing a rapid rise in the reactor temperature. Excessive temperature can lead to a series of serious consequences, such as increasing the pressure inside the reactor beyond its design range, potentially causing an explosion or other serious safety accidents, severely damaging production equipment, and posing a significant threat to the lives of operators. Furthermore, excessively high temperatures can cause side reactions such as decomposition and polymerization of reactants and products, further affecting product quality, resulting in waste of raw materials and economic losses. Utility Model Content
[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a safe feeding system for a solid-liquid two-phase reactor in chemical production. This system utilizes a membrane filter, activated carbon adsorption tower, and dehydration tower to perform multi-stage filtration and impurity removal of hydrogen, eliminating impurities and moisture. A preheater is used to preheat the hydrogen to a suitable reaction temperature, thereby improving production quality and efficiency. A high-level coolant storage tank is installed; during normal operation, the coolant flows through a high-level outlet pipe into a temperature control jacket to cool the reactor. In the event of a sudden power outage, the coolant falls through a low-level outlet pipe to the temperature control jacket under gravity, achieving timely cooling of the reactor and ensuring controllable reactor temperature, enabling effective control of the reaction in emergency situations.
[0005] This utility model is achieved using the following technical solution:
[0006] The aforementioned safe feeding system for a solid-liquid two-phase reactor in chemical production includes a reactor and a membrane filter. The membrane filter is connected to a dehydration tower via an activated carbon adsorption tower. The dehydration tower is connected to the reactor via a preheater. The reactor is connected to a distillation tower via a gas-liquid separator. The distillation tower is connected to a storage tank via a rectification tower. A temperature control sleeve is provided on the outside of the reactor, and a high-level coolant storage tank is connected to the temperature control sleeve. A liquid phase feed tank is connected to the reactor.
[0007] The reactor, as the core of the solid-liquid two-phase reaction, has an internal stirring device that promotes thorough mixing of the solid and liquid phases, facilitating the hydrogenation reaction of nitrobenzene and hydrogen under the action of a catalyst to produce aniline. The gas phase disperser below ensures the uniform dispersion of hydrogen and other gaseous materials to participate in the reaction. The preheater contains a preheater coil that can be connected to heat exchange pipes from the heat exchanger, utilizing the heat from the distillation column products for preheating, thus achieving efficient heat utilization.
[0008] The membrane filter is connected to a gas-phase feed pipe, the preheater is equipped with a preheater coil, and a one-way valve is provided between the preheater and the reactor.
[0009] The reactor is equipped with a stirring device inside, and a gas phase disperser is located below the reactor. A one-way valve is connected to the gas phase disperser through a pipeline.
[0010] The liquid phase feed tank is connected to a liquid phase feed pipe, and the high-level coolant storage tank is connected to a refrigeration unit.
[0011] The temperature control sleeve is connected to the refrigeration unit via a pipe. The upper part of the high-level coolant storage tank is connected to the temperature control sleeve via a high-level outlet pipe, and the bottom of the high-level coolant storage tank is connected to the high-level outlet pipe via a low-level outlet pipe.
[0012] The elevated coolant storage tank stores coolant. During normal operation, it supplies coolant to the temperature control jacket outside the reactor via the elevated outlet pipe. In the event of a power outage, the coolant flows down to the temperature control jacket via the low-level outlet pipe due to gravity, continuously cooling the reactor. The installation of both elevated and low-level outlet pipes creates a dual-mode cooling mechanism, ensuring the reliability of reactor temperature control. This effectively controls the reactor temperature under both normal and sudden power outage conditions, preventing safety accidents and product quality issues caused by abnormal temperatures, and ensuring safe and stable production.
[0013] A high-pressure nitrogen tank is connected to the pipeline between the one-way valve and the reactor. The top of the distillation tower is connected to the reactor via a gas phase return pipeline, and the top of the gas-liquid separator is connected to the gas phase return pipeline via a pipeline. The high-pressure nitrogen tank is used to fill the reactor with high-pressure nitrogen when needed (especially in the event of a sudden power outage) for operations such as purging and pressure maintenance.
[0014] A heat exchanger is provided between the distillation column and the storage tank. The heat exchanger is equipped with a heating water inlet pipe and is connected to the preheater coil through the heat exchange pipe.
[0015] The heat exchanger performs heat exchange treatment on the products from the distillation column, recovers heat, and transfers the heat to the preheater coil for preheating hydrogen.
[0016] Production Process: Hydrogen gas from the gas source first enters a membrane filter, where larger particles and dust are intercepted. Then, the hydrogen enters an activated carbon adsorption tower to remove harmful impurities such as sulfides, followed by a dehydration tower to remove moisture. The purified hydrogen then enters a preheater, where heat recovered from a heat exchanger is used to preheat the hydrogen to a suitable reaction temperature, typically controlled between 150-250°C, providing suitable reaction conditions for the subsequent hydrogenation reaction. Liquid raw materials such as nitrobenzene are stored in a liquid feed tank and stably transported to the reactor via a liquid feed pipeline. The nitrobenzene hydrogenation reaction takes place in the reactor, with the reaction temperature typically controlled between 180-250°C and the pressure maintained at 0.5-2.0 MPa. The reactor is equipped with a stirring device to ensure thorough mixing of the solid and liquid phases. A gas-phase disperser at the bottom evenly disperses the preheated hydrogen in the reaction system, promoting the hydrogenation reaction of nitrobenzene and hydrogen under the action of a catalyst to produce aniline. During normal operation, the refrigeration unit cools the coolant in the high-level coolant storage tank to a suitable temperature (e.g., 5-15℃). The coolant then flows through the high-level outlet pipe into the temperature control jacket outside the reactor, carrying away the heat generated by the reaction and maintaining a stable temperature inside the reactor. The gas-liquid mixture after the reaction enters the gas-liquid separator from the reactor, where the gas and liquid phases are initially separated. The gas phase mainly contains unreacted hydrogen and aniline vapor, while the liquid phase contains aniline and a small amount of unreacted nitrobenzene. The gas phase separated by the gas-liquid separator enters the distillation column. Through distillation, based on the differences in boiling points of different substances, low-boiling-point unreacted hydrogen and some aniline vapor are separated. The unreacted hydrogen returns to the reactor through the gas phase return pipe to continue participating in the reaction. The product obtained at the bottom of the distillation column enters the rectification column for further purification, removing residual impurities and unreacted substances, ultimately yielding high-purity aniline. The rectified aniline is then stored in a storage tank. In the event of a sudden power outage, the low-level outlet pipe at the bottom of the high-level coolant storage tank comes into play. The coolant flows into the temperature control jacket through the low-level outlet pipe under gravity, continuously cooling the reactor and preventing the reactor temperature from becoming too high due to the inability to stop the reaction immediately and poor heat dissipation, thus avoiding safety accidents.
[0017] Compared with the prior art, the beneficial effects of this utility model are:
[0018] (1) This system adopts a multi-stage purification and preheating approach. First, hydrogen enters the membrane filter through the gas-phase feed pipe. Through the filtration effect of the membrane, solid substances such as dust and larger particulate impurities in the hydrogen are intercepted, initially improving the purity of the hydrogen. Subsequently, the hydrogen enters the activated carbon adsorption tower. Utilizing the adsorption characteristics of activated carbon, harmful impurities such as residual sulfides in the hydrogen are further removed, significantly reducing the impurity content. Next, the hydrogen enters the dehydration tower to effectively remove moisture and prevent moisture from adversely affecting the reaction. After impurity removal, the hydrogen enters the preheater. The preheater coil inside the preheater is connected to the heat exchange pipes from the heat exchanger. The heat from the distillation tower products is used to preheat the hydrogen to reach a suitable reaction temperature, thereby improving the initial reaction rate and stability, and enhancing production quality and efficiency.
[0019] (2) This system is equipped with a high-level coolant storage tank and a dual-mode cooling mechanism. Under normal operating conditions, the chiller continuously cools the coolant in the high-level coolant storage tank to maintain its low temperature. The coolant flows into the temperature control sleeve outside the reactor through the high-level outlet pipe, carrying away the heat inside the reactor and achieving temperature control of the reactor to ensure that the reaction proceeds at a suitable temperature. In the event of a sudden power outage, the chiller and other equipment stop operating due to the loss of power supply. However, the low-level outlet pipe at the bottom of the high-level coolant storage tank plays a role at this time. The coolant falls into the temperature control sleeve through the low-level outlet pipe by its own gravity, continuously cooling the reactor. Thus, even in an emergency without power supply, the reactor temperature can still be effectively controlled, avoiding safety accidents and product quality problems caused by excessive temperature, and ensuring the safety and stability of the production process. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the structural design of the safe feeding system for a solid-liquid two-phase reactor in chemical production according to this utility model.
[0021] In the diagram: 1. Reactor; 2. Membrane filter; 3. Activated carbon adsorption tower; 4. Dehydration tower; 5. Preheater; 6. Check valve; 7. Gas-liquid separator; 8. Distillation tower; 9. Rectification tower; 10. Heat exchanger; 11. Storage tank; 12. Refrigeration unit; 13. High-level coolant storage tank; 14. Liquid phase feed tank; 15. Liquid phase feed pipeline; 16. Gas phase feed pipeline; 17. High-pressure nitrogen tank; 18. Preheater coil; 19. Gas phase disperser; 20. Heating water inlet pipeline; 21. Heat exchange pipeline; 22. Gas phase return pipeline; 23. Temperature control jacket; 24. High-level liquid outlet pipeline; 25. Low-level liquid outlet pipeline. Detailed Implementation
[0022] To make the objectives and technical solutions of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings.
[0023] Example 1
[0024] like Figure 1 As shown, the solid-liquid two-phase reactor safety feeding system in chemical production includes a reactor 1, a membrane filter 2, an activated carbon adsorption tower 3 connected to a dehydration tower 4, a preheater 5 connected to the reactor 1, a gas-liquid separator 7 connected to a distillation tower 8, and a rectification tower 8 connected to a storage tank 11. A temperature control sleeve 23 is installed on the outside of the reactor 1, and a high-level coolant storage tank 13 is connected to the temperature control sleeve 23. A liquid feed tank 14 is connected to the reactor 1. A gas feed pipe 16 is connected to the membrane filter 2. A preheater coil 18 is installed inside the preheater 5, and a one-way valve 6 is installed between the preheater 5 and the reactor 1. A stirring device is installed inside the reactor 1, and a gas disperser 19 is installed below the reactor 1. The one-way valve 6 is connected to the gas disperser 19 via a pipe. Reactor 1 serves as the core of the solid-liquid two-phase reaction. An internal stirring device ensures thorough mixing of the solid and liquid phases, facilitating the hydrogenation reaction of nitrobenzene and hydrogen under the action of a catalyst to produce aniline. The gas phase disperser 19 below promotes the uniform dispersion of hydrogen and other gaseous materials for the reaction. A liquid phase feed pipe 15 is connected to the liquid phase feed tank 14, and a chiller 12 is connected to the high-level coolant storage tank 13. A temperature control jacket 23 is connected to the chiller 12 via a pipe. The upper part of the high-level coolant storage tank 13 is connected to the temperature control jacket 23 via a high-level outlet pipe 24, and the bottom of the high-level coolant storage tank 13 is connected to the high-level outlet pipe 24 via a low-level outlet pipe 25. A high-pressure nitrogen tank 17 is connected to the pipe between the one-way valve 6 and reactor 1. The top of the distillation tower 8 is connected to reactor 1 via a gas phase return pipe 22, and the top of the gas-liquid separator 7 is connected to the gas phase return pipe 22 via a pipe. A heat exchanger 10 is provided between the distillation column 9 and the storage tank 11. The heat exchanger 10 is provided with a heating water inlet pipe 20. The heat exchanger 10 is connected to the preheater coil 18 through the heat exchange pipe 21.
[0025] The safety feeding system for the solid-liquid two-phase reactor in the above-mentioned chemical production process includes the following steps during operation:
[0026] (1) Hydrogen comes from the gas source, first passes through the membrane filter 2 to intercept large particulate impurities and dust, then passes through the activated carbon adsorption tower 3 to remove impurities such as sulfides, and the dehydration tower 4 to remove moisture. Finally, it is preheated to 150-250℃ in the preheater 5 using the heat recovered by the heat exchanger 10. Liquid raw materials such as nitrobenzene are stored in the liquid feed tank 14 and are stably transported to the reactor 1 through the liquid feed pipe 15. (2) The reaction is carried out in the reactor 1 at 180-250℃ and 0.5-2.0MPa. The stirring device in the reactor makes the solid and liquid fully mixed, and the gas phase disperser 19 disperses the preheated hydrogen evenly, so that nitrobenzene and hydrogen react under the action of the catalyst to produce aniline. During normal operation, the refrigeration unit 12 cools the coolant in the high-level coolant storage tank 13 to 5-15℃ and discharges it through the high-level outlet pipe. (3) The gas-liquid mixture after the reaction enters the gas-liquid separator 7 for preliminary separation. The gas phase contains unreacted hydrogen and aniline vapor, while the liquid phase contains aniline and a small amount of unreacted nitrobenzene. The gas phase enters the distillation tower 8, where unreacted hydrogen and some aniline vapor are separated according to the difference in boiling point. The hydrogen returns to the reactor 1 through the gas phase return pipe 22. The bottom product of the distillation tower 8 enters the rectification tower 9, where it is further purified to obtain high-purity aniline, which is stored in the storage tank 11. (4) In the event of a sudden power outage, the low-level outlet pipe 25 at the bottom of the high-level coolant storage tank 13 plays a role. The coolant flows into the temperature control sleeve 23 by gravity, continuously cooling the reactor 1 and preventing the temperature from becoming too high due to the inability to terminate the reaction immediately and poor heat dissipation, thus avoiding a safety accident.
Claims
1. A safe feeding system for a solid-liquid two-phase reactor in chemical production, characterized in that, The reactor includes a reactor (1) and a membrane filter (2). The membrane filter (2) is connected to a dewatering tower (4) via an activated carbon adsorption tower (3). The dewatering tower (4) is connected to the reactor (1) via a preheater (5). The reactor (1) is connected to a distillation tower (8) via a gas-liquid separator (7). The distillation tower (8) is connected to a storage tank (11) via a rectification tower (9). A temperature control sleeve (23) is provided on the outside of the reactor (1). A high-level cooling liquid storage tank (13) is connected to the temperature control sleeve (23). A liquid feed tank (14) is connected to the reactor (1).
2. The safe feeding system for a solid-liquid two-phase reactor in chemical production according to claim 1, characterized in that, The membrane filter (2) is connected to a gas phase feed pipe (16), the preheater (5) is equipped with a preheater coil (18), and a one-way valve (6) is provided between the preheater (5) and the reactor (1).
3. The safe feeding system for a solid-liquid two-phase reactor in chemical production according to claim 2, characterized in that, The reactor (1) is equipped with a stirring device inside, and a gas phase disperser (19) is provided below the reactor (1). A one-way valve (6) is connected to the gas phase disperser (19) through a pipe.
4. The safe feeding system for a solid-liquid two-phase reactor in chemical production according to claim 1, characterized in that, The liquid phase feed tank (14) is connected to a liquid phase feed pipe (15), and the high-level coolant storage tank (13) is connected to a refrigeration unit (12).
5. The safe feeding system for a solid-liquid two-phase reactor in chemical production according to claim 4, characterized in that, The temperature control sleeve (23) is connected to the refrigeration unit (12) through a pipe. The upper part of the high-level coolant storage tank (13) is connected to the temperature control sleeve (23) through the high-level liquid outlet pipe (24). The bottom of the high-level coolant storage tank (13) is connected to the high-level liquid outlet pipe (24) through the low-level liquid outlet pipe (25).
6. The safe feeding system for a solid-liquid two-phase reactor in chemical production according to claim 2, characterized in that, A high-pressure nitrogen tank (17) is connected to the pipeline between the one-way valve (6) and the reactor (1). The top of the distillation tower (8) is connected to the reactor (1) through the gas phase return pipeline (22). The top of the gas-liquid separator (7) is connected to the gas phase return pipeline (22) through a pipeline.
7. The safe feeding system for a solid-liquid two-phase reactor in chemical production according to claim 2, characterized in that, A heat exchanger (10) is provided between the distillation column (9) and the storage tank (11). The heat exchanger (10) is provided with a heating water inlet pipe (20). The heat exchanger (10) is connected to the preheater coil (18) through the heat exchange pipe (21).