Primary amine rectification purification system

Abstract

The utility model relates to primary amine production technical field, concretely is primary amine rectification purification system. Primary amine rectification purification system, including storage tank, storage tank is connected with rectifying column through heat exchanger, and the bottom of rectifying column is connected with membrane evaporator through pipeline, and the inside of rectifying column is equipped with primary condenser, and rectifying column is connected with gas -liquid separation tank through secondary condenser. The system is through the additional membrane evaporator, and the liquid phase material of rectifying column bottom discharge is handled again. The unique structure design of membrane evaporator makes it can distribute liquid material into film shape evenly, greatly increases evaporation area, strengthens mass transfer process, further separates the primary amine and impurity remaining in liquid phase, significantly improves the purity of product, satisfies the strict requirement of high -end application field to primary amine high purity.

Description

Technical Field

[0001] This utility model relates to the field of primary amine production technology, specifically a primary amine distillation and purification system. Background Technology

[0002] Primary amines are an important class of organic compounds with wide applications in many fields such as chemical engineering, pharmaceuticals, and materials. Due to the presence of an amino group (-NH2) in their molecular structure, they possess unique chemical activity, can participate in a variety of chemical reactions, and are key raw materials for the synthesis of many fine chemicals.

[0003] Distillation is a commonly used key technology in the production and purification of primary amines. However, traditional primary amine distillation units have many limitations. On the one hand, existing units often rely solely on distillation columns for purification, a single method that cannot meet the growing demand for high-purity primary amines. Especially when processing liquid materials, the complexity of the gas-liquid mass transfer process within the distillation column and the fact that some impurities have boiling points similar to primary amines result in insufficient purification, leaving a significant amount of impurities in the product and affecting its subsequent application performance. On the other hand, the low temperature of the feedstock entering the distillation column negatively impacts distillation efficiency. Low-temperature feedstock requires substantial energy to heat up, leading to uneven heat distribution within the column, prolonging the time to reach a stable distillation state, reducing yield per unit time, and increasing production costs. Utility Model Content

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a primary amine distillation and purification system. This system utilizes a thin-film evaporator to further process the liquid material discharged from the bottom of the distillation column. The unique structural design of the thin-film evaporator allows it to uniformly distribute the liquid material into a thin film, significantly increasing the evaporation area, enhancing the mass transfer process, and further separating residual primary amines and impurities from the liquid phase. This significantly improves the purity of the product and meets the stringent requirements for high-purity primary amines in high-end applications.

[0005] This utility model is achieved using the following technical solution:

[0006] The primary amine distillation and purification system includes a storage tank, which is connected to a distillation column via a heat exchanger. The bottom of the distillation column is connected to a thin-film evaporator via a pipe. The distillation column is equipped with a primary condenser and is connected to a gas-liquid separator via a secondary condenser.

[0007] The storage tank is equipped with an insulation sleeve on the outside, a discharge pump is installed between the storage tank and the heat exchanger, and a flow stabilizer is installed between the discharge pump and the heat exchanger.

[0008] The distillation column is connected to a reboiler, the primary condenser is equipped with a spray plate, and the distillation column is equipped with a recovery tank, which is connected to the spray plate through a pipeline.

[0009] The distillation column is equipped with multiple layers of trays or packing to facilitate gas-liquid mass transfer. A primary condenser is installed inside the column to initially condense the rising gas phase, optimizing the gas-liquid balance within the column. A reboiler is connected to the top of the column to provide heat for the distillation process, causing the liquid to vaporize and generate the rising gas phase. Simultaneously, a recovery tank is installed on the distillation column, connected to a spray plate via piping. The spray plate evenly sprays the liquid from the recovery tank onto the surface of the primary condenser, enhancing the condensation effect. Through multiple gas-liquid mass and heat transfer processes within the column, preliminary separation of primary amines from impurities is achieved. The synergistic effect of the primary condenser and the spray plate improves the condensation efficiency of the overhead gas phase, reduces the impurity content in the overhead product, and improves product quality. The reboiler provides stable heat, ensuring the continuous operation of the distillation process and maintaining the gas-liquid balance and stable distillation conditions within the column.

[0010] The thin-film evaporator is connected to the liquid storage tank via a pipe, and the primary condenser is connected to the primary condenser inlet pipe. The primary condenser is connected to the heat exchanger via a heating pipe.

[0011] The connection between the secondary condenser and the distillation column is located at the top of the distillation column, and the secondary condenser is connected to the liquid storage tank through a gas-liquid separator.

[0012] The secondary condenser is equipped with a secondary condenser coil, which is connected to the distillation column and the gas-liquid separator. A condensate inlet pipe is connected to the bottom of the secondary condenser, and a condensate outlet is provided on the top of the secondary condenser.

[0013] A thin-film evaporator mainly consists of a heating jacket, rotor, scrapers, inlet, outlet, and vacuum system. The heating jacket is used to introduce the heating medium, providing heat for the evaporation process. Scrapers are installed on the rotor; after the material enters the evaporator, it is evenly distributed on the inner wall of the evaporator under the action of the scrapers, forming a thin film, greatly increasing the evaporation area. This allows for further processing of the liquid phase discharged from the bottom of the distillation column. The formation of the thin-film material significantly increases the evaporation area, enhances the mass transfer process, and can further separate residual primary amines and impurities in the liquid phase, significantly improving the purity of the product. Operating under vacuum conditions lowers the boiling point of the material, making it suitable for processing heat-sensitive materials and reducing the risk of material decomposition or deterioration due to high temperatures.

[0014] The working principle of this utility model is as follows:

[0015] Temperature conditions: The top temperature of the distillation column is controlled within a range compatible with the boiling point of the primary amine product, determined according to the specific type of primary amine, between 50-100℃. The bottom temperature is controlled by the reboiler, higher than the top temperature, at approximately 100-150℃, to ensure sufficient vaporization and mass transfer of the material within the column. The heating temperature of the thin-film evaporator is set according to the properties of the primary amine and impurities, between 80-120℃, while maintaining a certain degree of vacuum in the system to lower the boiling point of the material and improve evaporation efficiency. The heat exchanger preheats the feedstock to near the suitable feed temperature of the distillation column, between 40-60℃.

[0016] Pressure conditions: The distillation column operates under atmospheric or slightly positive pressure conditions, with the pressure controlled at 1-1.2 atm to ensure the stable gas-liquid mass transfer process within the column. The thin-film evaporator operates under vacuum conditions, with the vacuum level maintained at -0.08 to -0.09 MPa, to lower the boiling point of the material and promote the evaporation process.

[0017] Flow conditions: The feed flow rate into the distillation column is precisely controlled by the discharge pump and flow stabilizer. Based on the distillation column's processing capacity and product quality requirements, the feed flow rate is stabilized within a certain range, such as 5-10 m³ / h. 3 At the same time, the cooling medium flow rates of the primary and secondary condensers are reasonably adjusted to ensure that the gaseous material can be fully condensed. The cooling medium flow rate is adjusted in real time according to the temperature and flow rate of the gaseous material.

[0018] Compared with the prior art, the beneficial effects of this utility model are:

[0019] (1) By adding a thin-film evaporator, the liquid material discharged from the bottom of the distillation column is further processed. The unique structural design of the thin-film evaporator enables it to uniformly distribute the liquid material into a thin film, which greatly increases the evaporation area, strengthens the mass transfer process, further separates the residual primary amines and impurities in the liquid phase, significantly improves the purity of the product, and meets the strict requirements of high purity of primary amines in high-end application fields.

[0020] (2) A heat exchanger is installed to preheat the raw material entering the distillation column using the residual heat from the distillation process. This increases the temperature of the raw material entering the distillation column, reduces the energy consumption for heating the raw material in the distillation column, makes the heat distribution in the distillation column more reasonable, accelerates the gas-liquid mass transfer rate, shortens the time required to reach a stable distillation state, thereby improving the distillation efficiency, increasing the output per unit time, and reducing the production cost.

[0021] (3) The combined design of the primary and secondary condensers enhances the condensation effect on the gaseous material at the top of the tower. The primary condenser initially cools the gaseous material, while the secondary condenser further condenses it, ensuring that the primary amine in the gaseous phase can be fully recovered, reducing product loss, and improving the product recovery rate, thereby further enhancing the economic benefits of the entire system. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the primary amine distillation and purification system of this invention;

[0023] In the diagram: 1. Storage tank; 2. Distillation column; 3. Heat exchanger; 4. Thin-film evaporator; 5. Secondary condenser; 6. Gas-liquid separator; 7. Liquid storage tank; 8. Storage tank insulation jacket; 9. Discharge pump; 10. Flow stabilizer; 11. Primary condenser; 12. Spray tray; 13. Recovery tank; 14. Reboiler; 15. Secondary condenser coil; 16. Condensate inlet pipe; 17. Condensate outlet; 18. Primary condenser inlet pipe; 19. Heating pipe. Detailed Implementation

[0024] 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.

[0025] Example 1

[0026] like Figure 1As shown, the primary amine distillation and purification system includes a storage tank 1, which is connected to a distillation column 2 via a heat exchanger 3. The bottom of the distillation column 2 is connected to a thin-film evaporator 4 via a pipe. A primary condenser 11 is installed inside the distillation column 2, and the distillation column 2 is connected to a gas-liquid separator 6 via a secondary condenser 5. An insulation jacket 8 is installed on the outside of the storage tank 1. A discharge pump 9 is installed between the storage tank 1 and the heat exchanger 3, and a flow stabilizer 10 is installed between the discharge pump 9 and the heat exchanger 3. A reboiler 14 is connected to the distillation column 2. A spray plate 12 is installed on the primary condenser 11, and a recovery tank 13 is installed on the distillation column 2, connected to the spray plate 12 via a pipe. The thin-film evaporator 4 is connected to a storage tank 7 via a pipe. A primary condenser inlet pipe 18 is connected to the primary condenser 11, and the primary condenser 11 is connected to the heat exchanger 3 via a heating pipe 19. The connection between the secondary condenser 5 and the distillation column 2 is located at the top of the distillation column 2. The secondary condenser 5 is connected to the liquid storage tank 7 via the gas-liquid separator 6. The secondary condenser 5 contains a secondary condenser coil 15, which is connected to the distillation column 2 and the gas-liquid separator 6. A condensate inlet pipe 16 is connected to the bottom of the secondary condenser 5, and a condensate outlet 17 is located on the top of the secondary condenser 5. A flow stabilizer is used to stabilize the flow rate and pressure of the feedstock, reducing the impact of flow fluctuations on the distillation process. This ensures a more uniform and stable flow rate of the feedstock entering the distillation column 2, contributing to the stable gas-liquid mass transfer process within the distillation column and improving distillation efficiency and product quality stability.

[0027] The above-mentioned primary amine distillation and purification system includes the following steps during operation:

[0028] (1) The primary amine feedstock to be distilled is stored in storage tank 1. Under the action of discharge pump 9, the feedstock passes through flow stabilizer 10 and heat exchanger 3 in sequence. Flow stabilizer 10 stabilizes the feedstock flow rate. Heat exchanger 3 uses the residual heat generated in the distillation process to preheat the feedstock and raise its temperature before it is sent to distillation column 2. (2) The preheated feedstock enters distillation column 2. Reboiler 14 connected to the bottom of distillation column 2 provides heat to vaporize part of the liquid in the column, generating rising gas phase. The rising gas phase and the falling liquid phase undergo multiple gas-liquid mass transfer and heat transfer processes in the column. The first-stage condenser 11 in distillation column 2 performs preliminary condensation of the rising gas phase. Spray plate 12 sprays the liquid in recovery tank 13 onto the surface of the first-stage condenser 11 to enhance the condensation effect. Part of the condensate is returned to distillation column 2 to maintain the gas-liquid balance in the column, and the rest is collected as the top product of the column. (3) The liquid phase material containing residual primary amine and impurities discharged from the bottom of distillation column 2 enters thin film evaporator 4. Inside the thin-film evaporator 4, the material is uniformly distributed into a thin film. Under vacuum and heating conditions, volatile components such as primary amines evaporate rapidly, and the gas phase enters the subsequent condensation and recovery system. The remaining heavy components are discharged into the storage tank 7 for further processing. (4) The gas phase material discharged from the top of the distillation column 2 that has not been completely condensed by the primary condenser 11 enters the secondary condenser 5. The secondary condenser coil 15 inside the secondary condenser 5 further cools the gas phase to ensure complete condensation. The condensed liquid enters the gas-liquid separator 6 through the condensate inlet pipe 16. Gas-liquid separation is carried out in the gas-liquid separator 6. The liquid flows into the storage tank 7 for storage, and the small amount of uncondensed gas is treated according to environmental protection requirements.

Claims

1. A primary amine distillation purification system, characterized in that, It includes a storage tank (1), which is connected to a distillation column (2) via a heat exchanger (3). The bottom of the distillation column (2) is connected to a thin film evaporator (4) via a pipe. The interior of the distillation column (2) is equipped with a primary condenser (11), and the distillation column (2) is connected to a gas-liquid separator (6) via a secondary condenser (5).

2. The primary amine distillation and purification system according to claim 1, characterized in that, The storage tank (1) is provided with a storage tank insulation sleeve (8) on the outside, and a discharge pump (9) is provided between the storage tank (1) and the heat exchanger (3), and a flow stabilizer (10) is provided between the discharge pump (9) and the heat exchanger (3).

3. The primary amine distillation and purification system according to claim 1, characterized in that, The distillation column (2) is connected to a reboiler (14), the primary condenser (11) is equipped with a spray plate (12), and the distillation column (2) is equipped with a recovery tank (13), which is connected to the spray plate (12) through a pipe.

4. The primary amine distillation and purification system according to claim 1, characterized in that, The thin film evaporator (4) is connected to the liquid storage tank (7) through a pipe. The first-stage condenser (11) is connected to the first-stage condenser inlet pipe (18). The first-stage condenser (11) is connected to the heat exchanger (3) through the heating pipe (19).

5. The primary amine distillation and purification system according to claim 4, characterized in that, The connection between the secondary condenser (5) and the distillation column (2) is located at the top of the distillation column (2), and the secondary condenser (5) is connected to the liquid storage tank (7) through the gas-liquid separator (6).

6. The primary amine distillation and purification system according to claim 5, characterized in that, The secondary condenser (5) is equipped with a secondary condenser coil (15) inside. The secondary condenser coil (15) is connected to the distillation column (2) and the secondary condenser coil (15) is connected to the gas-liquid separator (6). A condensate inlet pipe (16) is connected below the secondary condenser (5), and a condensate outlet (17) is provided on the secondary condenser (5).

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