A device for the primary distillation of dicyclohexylamine

Abstract

A kind of for dichloroethane initial distillation device, including vertical cylinder and the base of cylinder bottom setting, gas outlet is provided in the center of cylinder top end head, the cylinder below heat exchange cavity is divided into intercommunication reaction cavity by multiple layers of grid plate, the cylinder in each layer grid plate top is filled with packing respectively, the cylinder in the topmost packing top is provided with feeding distributor, the cylinder in feeding distributor top is provided with feeding pipe in communication with outside, the heat exchanger of multiple heat exchange pipes is communicated with the top of reaction cavity by passing through heat exchange cavity, the cylinder in discharge elbow top is fixedly connected with gas phase inlet pipe.This utility model can make dichloroethane be enriched to a certain extent, can separate out most of the impurities with the dichloroethane boiling point difference larger, reduce the material complexity and processing capacity of subsequent rectification etc separation equipment, improve the efficiency and economy of entire production process, provide more favorable conditions for subsequent rectification etc operation of further purifying dichloroethane.

Description

Technical Field

[0001] This utility model relates to a dicyclohexylamine production apparatus, specifically a dicyclohexylamine primary distillation apparatus. Background Technology

[0002] Aniline reacts with hydrogen in the presence of a catalyst to produce crude dicyclohexylamine, which needs to be separated in a primary distillation column. The primary distillation column removes light components such as benzene, cyclohexane, and water from the crude product under vacuum conditions via a condenser. The column operates at a vacuum of -0.060 MPa to -0.070 MPa and a condenser temperature of 50°C to 85°C. These light components, in gaseous form, pass through the top condenser and are condensed into a fore-distillate residue, which then enters the fore-distillate residue tank. The cyclohexylamine processed in the primary distillation column is further refined in a rectification column to obtain industrial-grade cyclohexylamine. However, current primary distillation column designs are flawed, making it difficult to vaporize dicyclohexylamine and some impurities with relatively low boiling points, resulting in incomplete gas-liquid separation. Furthermore, the top temperature is difficult to control, hindering the separation efficiency. Utility Model Content

[0003] In order to solve the above problems, the purpose of this utility model is to provide a dicyclohexylamine primary distillation apparatus.

[0004] To achieve the above objectives, the technical solution of this utility model is as follows: a dicyclohexylamine primary distillation device, comprising a vertical cylinder and a base at the bottom of the cylinder, an outlet at the center of the top end cap of the cylinder, a pressure chamber formed by a partition separating the top end cap of the cylinder, a heat exchange chamber formed by a partition separating the cylinder below the pressure chamber, and a reaction chamber formed by a multi-layer grid plate dividing the cylinder below the heat exchange chamber into interconnected reaction chambers, each layer of the cylinder above the grid plate being filled with packing material, a feed distributor being provided in the cylinder above the top packing material, a feed pipe connected to the outside being provided in the cylinder above the feed distributor, a heat exchanger composed of multiple heat exchange tubes passing through the heat exchange chamber to connect the top of the pressure chamber and the reaction chamber, a discharge bend pipe connected to the outside of the cylinder being fixedly connected to the bottom end cap of the reaction chamber, and a gas phase inlet pipe being fixedly connected to the cylinder above the discharge bend pipe.

[0005] Furthermore, multiple horizontally arranged baffles are installed inside the heat exchange cavity, and the upper and lower baffles are fixedly connected to the inner wall of the cylinder on opposite sides, so that the upper and lower baffles form a meandering flow channel in the heat exchange cavity. A circulating water inlet is provided on one side of the bottom of the heat exchange cavity, and a circulating water outlet is provided on the top of the other side of the heat exchange cavity.

[0006] Furthermore, the lower end of the cylinder is a conical skirt cylinder, and the upper end of the skirt cylinder is the bottommost end cap structure inside the cylinder. The bottom of the skirt cylinder is supported and fixed on the base.

[0007] Furthermore, each layer of grid plate has a serrated collector installed inside the cylinder.

[0008] Furthermore, exhaust holes are provided on both sides of the top of the skirt base cylinder, a bottom manhole is provided on one side of the bottom of the skirt base cylinder, and a side manhole is provided on one side of the cylinder above each layer of grid plate.

[0009] Furthermore, level gauge interfaces are provided at the top and bottom of the pressure chamber inside the cylinder.

[0010] Furthermore, multiple temperature and pressure measuring ports are provided on the top and side walls of the cylinder.

[0011] Furthermore, the top of the cylinder is also equipped with a thermometer port and a pressure gauge interface.

[0012] With the above settings, the role and advantages of this utility model in the production of dicyclohexylamine are as follows:

[0013] Preliminary separation: In the production process of dicyclohexylamine, the product after the reaction is usually a mixture containing dicyclohexylamine, unreacted raw materials, intermediate products and by-products. This invention can perform preliminary separation of these mixtures, separating the low-boiling-point light components and the high-boiling-point heavy components, so that dicyclohexylamine can be enriched to a certain extent.

[0014] Reduced load on subsequent processing: Through the preliminary separation of this invention, most impurities with large differences in boiling point from dicyclohexylamine can be separated, reducing the complexity and throughput of materials entering subsequent separation equipment such as distillation, improving the efficiency and economy of the entire production process, and providing more favorable conditions for subsequent distillation and other operations to further purify dicyclohexylamine. Attached Figure Description

[0015] The present invention will now be further described with reference to the accompanying drawings.

[0016] Figure 1 This is a schematic diagram of the main structure of this utility model;

[0017] Figure 2 This is a schematic diagram of the shortened structure of this utility model. Detailed Implementation

[0018] like Figure 1-2As shown, a dicyclohexylamine primary distillation apparatus includes a vertical cylinder 1 and a base 2 at the bottom of the cylinder 1. A gas outlet 3 is provided at the center of the top end cap of the cylinder 1. The top end cap of the cylinder 1 is separated by a partition to form a pressure chamber 4. The cylinder 1 below the pressure chamber 4 is separated to form a heat exchange chamber 5. The cylinder 1 below the heat exchange chamber 5 is divided into interconnected reaction chambers by multiple layers of grid plates 6. Each layer of grid plate 6 is filled with packing material 7. A feed distributor 8 is provided in the cylinder 1 above the top packing material 7. A feed pipe 9 communicating with the outside is provided in the cylinder 1 above the feed distributor 8. A heat exchanger 10 composed of multiple heat exchange tubes passes through the heat exchange chamber 5 to connect the pressure chamber 4 with the top of the reaction chamber. A discharge bend 11 communicating with the outside of the cylinder 1 is fixedly connected to the bottom end cap of the reaction chamber. A gas phase inlet pipe 12 is fixedly connected to the cylinder 1 above the discharge bend 11.

[0019] Specifically: The heat exchange chamber 5 is provided with multiple horizontally arranged baffles 13, and the upper and lower baffles 13 are fixedly connected to the inner wall of the cylinder 1 on opposite sides, so that the upper and lower baffles 13 form a meandering flow channel in the heat exchange chamber 5. A circulating water inlet 14 is provided on one side of the bottom of the heat exchange chamber 5, and a circulating water outlet 15 is provided on the top of the other side of the heat exchange chamber 5.

[0020] The lower end of the cylinder 1 is a conical skirt cylinder 16, and the upper end of the skirt cylinder 16 is the end cap structure at the bottom of the cylinder 1. The bottom of the skirt cylinder 16 is supported and fixed on the base 2. Vent holes 18 are provided on both sides of the top of the skirt cylinder 16. A bottom manhole 19 is provided on one side of the bottom of the skirt cylinder 16. A side manhole is also provided on one side of the cylinder 1 above each layer of grid plate 6.

[0021] The pressure chamber 4 inside the cylinder 1 is provided with a liquid level gauge interface 20 at the top and bottom for easy connection of a liquid level gauge. The top and side walls of the cylinder 1 are also provided with multiple temperature measuring ports 21 and pressure measuring ports 22 for easy connection of thermometers and pressure gauges. In addition, a serrated collector 17 is provided in the cylinder 1 below each layer of grid plate 6. The collector 17 and the feed distributor 8 are existing devices in the field and are easy to purchase from the market, so their structure will not be described in detail here.

[0022] The structural features of this utility model are as follows: it is generally a cylindrical structure made of corrosion-resistant metal materials such as stainless steel to withstand the temperature, pressure and corrosion of materials inside the tower. Its height and diameter are determined according to the production scale and separation requirements. The height usually ranges from several meters to tens of meters, and the diameter also has various specifications.

[0023] Feed inlet: can be located at an appropriate position in the tower body, used to introduce the mixture containing dicyclohexylamine to be separated into the tower. The location and number of feed inlets are determined according to factors such as material properties, tower structure and operating requirements.

[0024] The outlets include the top outlet (i.e., the gas outlet 3) and the bottom outlet (i.e., the outlet bend 11). The top outlet is used to discharge the vapor rich in light components (which may contain dicyclohexylamine and some low-boiling-point impurities) after preliminary separation, which is then condensed to obtain the corresponding distillate. The bottom outlet discharges the liquid containing heavy components (high-boiling-point impurities, etc.).

[0025] Condenser and reboiler: The condenser (i.e., heat exchanger 10) is located at the top of the column and is used to cool and condense the rising steam into liquid; the reboiler (i.e., the skirted cylinder 16) is located at the bottom of the column and provides heat to the material in the column, causing the liquid to partially vaporize and generate rising steam, maintaining the gas-liquid balance and separation process in the column.

[0026] This invention involves hydrogenating aniline with hydrogen in the presence of a catalyst to produce crude dicyclohexylamine. The crude dicyclohexylamine is then fed into a primary distillation column for separation, thereby improving the purity of the product. The specific working principle is as follows:

[0027] Utilizing boiling point differences: Based on the different boiling points of the components in a mixture, a mixture containing dicyclohexylamine is heated. During heating, the components with lower boiling points vaporize first, while the components with higher boiling points remain in liquid form. For example, in a mixture of dicyclohexylamine and other impurities, dicyclohexylamine and some impurities with relatively lower boiling points will vaporize first.

[0028] Gas-liquid mass and heat transfer: Steam rises inside the column and comes into countercurrent contact with liquid flowing downwards from the top of the column. During the contact process, high-boiling-point components in the steam partially condense and enter the liquid phase when cooled, while low-boiling-point components in the liquid phase absorb heat and vaporize into the gas phase, thereby achieving the transfer and separation of substances between the gas and liquid phases.

[0029] Reflux effect: Part of the liquid condensed at the top of the column is taken out as product or distillate, and the other part is returned to the column as reflux liquid. The reflux liquid can control the temperature at the top of the column, making the light components purer, and at the same time providing a liquid medium for gas-liquid mass transfer in the column, thus improving the separation effect.

[0030] The above description is merely an illustrative embodiment of this utility model and is not intended to limit the scope of this utility model. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of this utility model should fall within the protection scope of this utility model.

Claims

1. A dicyclohexylamine primary distillation apparatus, comprising a vertical cylindrical body (1) and a base (2) disposed at the bottom of the cylindrical body (1), wherein an outlet (3) is disposed at the center of the top end cap of the cylindrical body (1), characterized in that: The top end cap of the cylinder (1) is separated by a partition to form a pressure chamber (4). The cylinder (1) below the pressure chamber (4) is separated to form a heat exchange chamber (5). The cylinder (1) below the heat exchange chamber (5) is divided into interconnected reaction chambers by multiple grid plates (6). Each layer of grid plate (6) is filled with packing material (7). The top packing material (7) is provided with a feed distributor (8) in the cylinder (1). The cylinder (1) above the feed distributor (8) is provided with a feed pipe (9) connected to the outside. A heat exchanger (10) composed of multiple heat exchange tubes passes through the heat exchange chamber (5) to connect the pressure chamber (4) and the top of the reaction chamber. The bottom end cap of the reaction chamber is fixedly connected to a discharge bend (11) connected to the outside of the cylinder (1). The cylinder (1) above the discharge bend (11) is fixedly connected to a gas phase inlet pipe (12).

2. The dicyclohexylamine primary distillation apparatus as described in claim 1, characterized in that: Multiple horizontally arranged baffles (13) are provided inside the heat exchange chamber (5), and the upper and lower baffles (13) are fixedly connected to the inner wall of the cylinder (1) on opposite sides, so that the upper and lower baffles (13) form a meandering flow channel in the heat exchange chamber (5). A circulating water inlet (14) is provided on one side of the bottom of the heat exchange chamber (5), and a circulating water outlet (15) is provided on the top of the other side of the heat exchange chamber (5).

3. The dicyclohexylamine primary distillation apparatus as described in claim 1, characterized in that: The lower end of the cylinder (1) is a conical skirt cylinder (16), and the upper end of the skirt cylinder (16) is the bottom end cap structure inside the cylinder (1). The bottom of the skirt cylinder (16) is fixed on the base (2).

4. The dicyclohexylamine primary distillation apparatus as described in claim 1, characterized in that: Each layer of grid plate (6) has a serrated collector (17) installed in the cylinder (1) below it.

5. The dicyclohexylamine primary distillation apparatus as described in claim 3, characterized in that: The top two sides of the skirt base cylinder (16) are provided with exhaust holes (18), the bottom side of the skirt base cylinder (16) is provided with a bottom manhole (19), and the side of the cylinder (1) above each layer of grid plate (6) is also provided with a side manhole.

6. The dicyclohexylamine primary distillation apparatus as described in claim 1, characterized in that: The pressure chamber (4) inside the cylinder (1) is equipped with a level gauge interface (20) at the top and bottom respectively.

7. The dicyclohexylamine primary distillation apparatus as described in claim 1, characterized in that: The top and side walls of the cylinder (1) are also provided with multiple temperature measuring ports (21) and pressure measuring ports (22).

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