A gasification mixing device for preparing 6-aminocapronitrile by gas phase method

Abstract

The utility model belongs to a kind of for the gasification mixing device of preparation 6-amino capro nitrile of gas phase method;Including shell, the top of shell is equipped with mixed gas discharge gate;The bottom of shell is equipped with not gasification liquid discharge gate;The inner upper portion of shell is equipped with liquid trapping unit, the lower portion of liquid trapping unit is equipped with annular liquid distributor for caprolactam feed, the lower portion of annular liquid distributor is equipped with ammonia gas feed unit for ammonia gas feed;Ammonia gas feed unit at least includes for making ammonia gas along shell inner wall uplink big annular gas distributor;With reasonable structure design, effectively reduce caprolactam in the process of gasification tar, carbon deposition, avoid its in subsequent process cover catalyst surface reduce catalyst activity, for realizing system long-period stable operation and improve product yield lay foundation.

Description

Technical Field

[0001] This invention belongs to the field of gas-phase preparation of 6-aminohexanonitrile, specifically a gasification mixing device for gas-phase preparation of 6-aminohexanonitrile. Background Technology

[0002] Hexamethylenediamine (HDMA) is an important chemical raw material, primarily used in the neutralization reaction with adipic acid to produce nylon 66 and in the reaction with sebacic acid to produce nylon 610. These are then used to manufacture various nylon resins, nylon fibers, and engineering plastics, making it a valuable intermediate in the synthesis of materials. HDMA is also used in the synthesis of diisocyanates and as a curing agent and organic crosslinking agent for urea-formaldehyde resins and epoxy resins. HDMA can be produced by hydrogenating 6-aminohexanonitrile. Currently, the synthesis of 6-aminohexanonitrile mainly uses caprolactam as a raw material, prepared through an ammoniation and dehydration reaction, including two main categories: gas-phase and liquid-phase methods. In the gas-phase production of 6-aminohexanonitrile, caprolactam needs to be vaporized. During vaporization, uneven heating can easily occur, producing tar and carbon deposits that coat the catalyst surface, reducing the number of active sites. This process not only significantly reduces the final product yield but also causes gradual catalyst deactivation, resulting in poor overall system stability.

[0003] Therefore, how to reduce tar and carbon deposits during the gasification and reaction of caprolactam, avoid them from covering the catalyst surface and reducing catalyst activity, and achieve long-term stable operation of the system and improve product yield have become urgent technical problems to be solved. Utility Model Content

[0004] To overcome the above deficiencies, this invention provides a gasification mixing device for the gas-phase preparation of 6-aminohexanonitrile, thereby solving the technical problems existing in the prior art.

[0005] The technical solution adopted by this utility model to solve its technical problem is:

[0006] A vaporization mixing apparatus for the gas-phase preparation of 6-aminohexanonitrile, the apparatus comprising a shell, a mixed gas outlet at the top of the shell, an unvaporized liquid outlet at the bottom of the shell, a liquid trapping unit in the upper inner part of the shell, an annular liquid distributor for caprolactam feeding at the lower part of the liquid trapping unit, and an ammonia feeding unit for ammonia feeding at the lower part of the annular liquid distributor; the ammonia feeding unit includes at least a large annular gas distributor for causing ammonia to rise along the inner wall of the shell.

[0007] The beneficial effects of this invention are as follows: By setting up an annular liquid distributor and a large annular gas distributor, countercurrent contact between liquid caprolactam and high-temperature ammonia gas can be achieved, thereby vaporizing caprolactam within the shell; and ammonia gas forms a rapidly flowing airflow along the inner wall of the shell, preventing caprolactam droplets from contacting the shell and reducing the likelihood of caprolactam stagnation on the inner wall under high-temperature conditions, leading to coking; in addition, a small amount of tar generated during the vaporization process is collected at the bottom of the vaporization mixing device by a liquid trap and discharged in appropriate amounts according to the liquid level and temperature, reducing the tar content in the vaporization system; the above process can effectively reduce the generation of tar and carbon deposits during the vaporization and reaction of caprolactam, preventing them from covering the catalyst surface and reducing catalyst activity, thus laying the foundation for achieving long-term stable operation of the system and improving product yield.

[0008] Preferably, the upper part of the large annular gas distributor is evenly distributed with a plurality of first vent holes, which are located on the outer side near the axis and at an angle θ1 with respect to the axis, where 0° < θ1 ≤ 90°.

[0009] Preferably, the ratio of the outer diameter of the large annular gas distributor to the inner diameter of the shell is 1:1 to 2.

[0010] Preferably, the ammonia feeding unit further includes a small annular gas distributor, the upper part of which is evenly distributed with a number of second vent holes, the second vent holes being located at an angle of θ2 with respect to the axis, -45°<θ2≤45°; the ratio of the outer diameter of the small annular gas distributor to the inner diameter of the shell is 1:2~5.

[0011] Preferably, the large annular gas distributor is located on one side close to the annular liquid distributor, and the small annular gas distributor is located at the lower part of the large annular gas distributor; atomizing nozzles are evenly distributed at the lower part of the annular liquid distributor.

[0012] Preferably, the outer diameter of the small annular gas distributor is larger than the outer diameter of the annular liquid distributor.

[0013] Preferably, the annular liquid distributor has caprolactam inlets symmetrically arranged on both sides, and the two caprolactam inlets are respectively connected to the preheated caprolactam liquid phase pipeline.

[0014] Preferably, the large annular gas distributor has a first ammonia inlet symmetrically arranged on both sides, and the small annular gas distributor has a second ammonia inlet symmetrically arranged on both sides. The first and second ammonia inlets are respectively connected to a high-temperature ammonia pipeline.

[0015] Preferably, the liquid trapping unit includes at least three layers of liquid traps arranged from top to bottom. Each liquid trap includes a circular perforated plate located in the middle, with a plurality of rectangular baffles evenly distributed on the outer circumference of the circular perforated plate. An annular liquid distributor is located at a corresponding position at the bottom of the middle of the liquid trap. The ratio of the outer diameter of the circular perforated plate to the inner diameter of the shell is 1:2 to 5.

[0016] Preferably, one end of the rectangular baffle is connected to the inner wall of the shell, and the other end of the rectangular baffle is connected to the outer wall of the circular perforated plate; the rectangular baffle (11) is inclined and its angle with the vertical direction is 45°.

[0017] A vaporization and mixing device for the gas-phase preparation of 6-aminohexanonitrile, manufactured according to the above scheme, is applicable to the vaporization and mixing of caprolactam in the gas-phase preparation of 6-aminohexanonitrile. By setting up an annular liquid distributor and a large annular gas distributor, countercurrent contact between liquid caprolactam and high-temperature ammonia gas can be achieved, thereby enabling the caprolactam to vaporize and mix within the shell. Furthermore, by setting up a large annular gas distributor, a rapid airflow of high-temperature ammonia gas can be formed along the inner wall of the shell, preventing caprolactam droplets from contacting the shell and reducing the possibility of caprolactam stagnation on the inner wall under high-temperature conditions, leading to coking. By setting up a small annular gas distributor, sufficient countercurrent contact with the atomized caprolactam can be achieved, not only realizing the thorough mixing of the two materials, but also ensuring sufficient contact between the atomized and atomized caprolactam gas. It also features uniform vaporization of caprolactam. Furthermore, the diameter of the annular liquid distributor in this invention is smaller than that of the large annular gas distributor, the small annular gas distributor, and the circular orifice plate. This design allows the preheated and atomized caprolactam droplets to be confined inside the large annular gas distributor, enabling them to fully countercurrently contact with the high-temperature ammonia gas from the large and small annular gas distributors, thus achieving thorough vaporization and mixing. Simultaneously, the circular orifice plate intercepts most of the tar. This design is reasonable, effectively reducing the generation of tar and carbon deposits during caprolactam vaporization, and preventing them from covering the catalyst surface and reducing catalyst activity in subsequent processes. This lays the foundation for long-term stable operation of the system and improved product yield. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of this utility model.

[0020] Figure 2 This is a schematic diagram of the structure of the annular liquid distributor of this utility model.

[0021] Figure 3 This is a schematic diagram of the liquid trap of this utility model.

[0022] Figure 4 This is a schematic diagram of the structure of the large annular gas distributor and the small annular gas distributor of this utility model.

[0023] Figure 5 This is a schematic diagram showing the setting range of the first vent hole of this utility model.

[0024] Figure 6 This is a schematic diagram showing the setting range of the second vent hole of this utility model.

[0025] Figure 7 This is a schematic diagram showing the tilt angle of the rectangular baffle of this utility model.

[0026] In the diagram: 1. Shell; 2. Liquid trap; 3. Annular liquid distributor; 4. Large annular gas distributor; 5. Small annular gas distributor; 6. Caprolactam inlet; 7. First ammonia inlet; 8. Unvaporized liquid outlet; 9. Mixed gas outlet; 10. Atomizing nozzle; 11. Rectangular baffle; 12. Circular orifice plate; 13. Second ammonia inlet; 14. First vent; 15. Second vent; 16. Preheated caprolactam liquid phase pipeline; 17. High-temperature ammonia pipeline. Detailed Implementation

[0027] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0028] The following is in conjunction with the appendix Figure 1To further describe this application in detail, this utility model is a gasification mixing device for the gas-phase preparation of 6-aminohexanonitrile. The gasification mixing device includes a shell 1, with a mixed gas outlet 9 at the top of the shell 1 and an unvaporized liquid outlet 8 at the bottom of the shell 1. A liquid collection unit is provided in the upper inner part of the shell 1, and an annular liquid distributor 3 for caprolactam feeding is provided below the liquid collection unit. An ammonia feeding unit for ammonia feeding is provided below the annular liquid distributor 3. The ammonia feeding unit includes at least a large annular gas distributor 4 for causing ammonia to rise along the inner wall of the shell 1. This invention is applicable to the vaporization of caprolactam and the thorough mixing of it with ammonia gas, which then enters the subsequent reaction stage through the mixed gas outlet 9. The essence of this invention is to prevent caprolactam from coking inside the shell 1 and to reduce tar production. To achieve this, this invention is equipped with a large annular gas distributor 4 that allows ammonia gas to rise along the inner wall of the shell 1, preventing caprolactam from the annular liquid distributor 3 from contacting the inner wall of the shell 1 and causing coking. At the same time, the generated tar is captured by a liquid collection unit and discharged through the unvaporized liquid outlet 8 under its own gravity, preventing it from entering the subsequent process.

[0029] Furthermore, such as Figure 1 , 4 As shown in Figure 5, the large annular gas distributor 4 has several first vent holes 14 evenly distributed on its upper part. The first vent holes 14 are located on the outer side near the axis and at an angle θ1 with the axis, where 0° < θ1 ≤ 90°. The main purpose of the large annular gas distributor 4 in this invention is to create a rapid gas flow along the inner wall of the shell 1, preventing caprolactam droplets from contacting the shell and reducing the possibility of caprolactam stagnating on the inner wall and causing coking under high temperature conditions. At the same time, it can also allow high-temperature ammonia to come into countercurrent contact with caprolactam, so that the caprolactam is vaporized and fully mixed with ammonia, creating conditions for the subsequent production of 6-aminohexanonitrile.

[0030] Furthermore, such as Figure 1 , 4 As shown, the ratio of the outer diameter of the large annular gas distributor 4 to the inner diameter of the housing 1 is 1:1 to 2.

[0031] Furthermore, such as Figure 1 , 4As shown in Figure 6, the ammonia feeding unit also includes a small annular gas distributor 5. Several second vent holes 15 are evenly distributed on the upper part of the small annular gas distributor 5. The second vent holes 15 are positioned at an angle θ2 with the axis, where -45° < θ2 ≤ 45°. The ratio of the outer diameter of the small annular gas distributor 5 to the inner diameter of the shell 1 is 1:2 to 5. By setting up the large annular gas distributor 4 and several first vent holes 14, an air curtain can be formed blocking the inner wall of the shell 1, allowing high-temperature ammonia and caprolactam to come into countercurrent contact. Based on the above setup, by setting up the small annular gas distributor 5 with second vent holes 15, the caprolactam in the middle can make sufficient countercurrent contact, thereby achieving sufficient vaporization of caprolactam and thorough mixing of the vaporized caprolactam with ammonia.

[0032] Furthermore, such as Figure 1 , 2 As shown, the large annular gas distributor 4 is located on one side near the annular liquid distributor 3, and the small annular gas distributor 5 is located below the large annular gas distributor 4; atomizing nozzles 10 are evenly distributed at the lower part of the annular liquid distributor 3. The above arrangement enables the atomized droplets to be evenly distributed in the vaporization space.

[0033] Furthermore, such as Figure 1 As shown, the outer diameter of the small annular gas distributor 5 is larger than the outer diameter of the annular liquid distributor 3. The high-temperature ammonia gas from the small annular gas distributor 5 and the high-temperature ammonia gas from the large annular gas distributor 4 form two barriers between the inner wall of the shell 1 and the caprolactam, preventing the caprolactam from contacting the inner wall of the shell 1, while simultaneously allowing the high-temperature ammonia gas from the small annular gas distributor 5 to achieve sufficient countercurrent contact with the caprolactam for vaporization.

[0034] Furthermore, such as Figure 1 , 2 As shown, the annular liquid distributor 3 has caprolactam inlets 6 symmetrically arranged on both sides, and the two caprolactam inlets 6 are respectively connected to the preheated caprolactam liquid phase pipeline 16. The above arrangement enables uniform feeding, ensuring that the pressure of caprolactam is balanced after entering the shell 1, further ensuring the atomization effect.

[0035] Furthermore, such as Figure 1 , 4 As shown, the large annular gas distributor 4 has symmetrically arranged first ammonia inlets 7 on both sides, and the small annular gas distributor 5 has symmetrically arranged second ammonia inlets 13 on both sides. The first ammonia inlets 7 and the second ammonia inlets 13 are respectively connected to the high-temperature ammonia pipeline 17. This arrangement enables uniform feeding of high-temperature ammonia, achieves pressure balance of high-temperature ammonia within the shell 1, and ensures uniform dispersion of the high-temperature ammonia.

[0036] Furthermore, such as Figure 1 , 3 As shown, the liquid collection unit includes at least three layers of liquid collectors 2 arranged from top to bottom. Each liquid collector 2 includes a circular perforated plate 12 located in the middle, with several rectangular baffles 11 evenly distributed on the outer circumference of the circular perforated plate 12. An annular liquid distributor 3 is located at a corresponding position at the bottom of the middle of the liquid collector 2. The ratio of the outer diameter of the circular perforated plate 12 to the inner diameter of the shell 1 is 1:2 to 5. The above arrangement enables the collection of droplets, which mainly consist of tar entrained in the gas phase and a small amount of unvaporized liquid caprolactam. In addition, during the descent of the droplets, the unvaporized liquid caprolactam can still come into countercurrent contact with high-temperature ammonia gas to fully utilize the raw materials. The liquid phase finally enters the bottom of the shell 1 and is discharged through the unvaporized liquid outlet 8.

[0037] Furthermore, such as Figure 3 , 7 As shown, one end of the rectangular baffle 11 is connected to the inner wall of the housing 1, and the other end of the rectangular baffle 11 is connected to the outer wall of the circular perforated plate 12; the rectangular baffle 11 is inclined, and the angle between it and the vertical direction is 45°. The inclined rectangular baffle 11 can capture droplets without increasing gas resistance too much.

[0038] The specific working process of this utility model is as follows: Preheated caprolactam enters the annular liquid distributor 3 through the caprolactam inlet 6. The liquid is atomized into small droplets in the gasification mixer via the atomizing nozzle 10. Part of the high-heat ammonia gas enters the large annular gas distributor 4 through the first ammonia inlet 7, causing the gas to flow rapidly along the inner wall of the shell 1, preventing caprolactam droplets from contacting the shell 1 and reducing the likelihood of caprolactam stagnation and coking on the inner wall under high-temperature conditions. Another part of the ammonia gas enters the small annular gas distributor 5 through the first ammonia inlet 13, causing the gas to come into countercurrent contact with the caprolactam spray inside the shell 1, causing it to vaporize. The vaporized mixed gas passes through the liquid collector 2 to collect unvaporized droplets and then enters the subsequent reactor through the mixed gas outlet 9 for further reaction. The unvaporized droplets and a small amount of tar generated during the vaporization process are collected at the bottom of the shell 1 through the liquid collector 2 and discharged in appropriate amounts through the unvaporized liquid outlet 8 according to the actual working conditions. The specific working process of this utility model is as follows: Step 1: Caprolactam is preheated to 220-270℃. The preheated caprolactam enters the annular liquid distributor 3 through the preheated caprolactam liquid phase pipeline 16 and the caprolactam inlet 6. The liquid is atomized into small droplets in the housing 1 by the atomizing nozzle 10. The number of liquid atomizing nozzles is determined according to the flow rate of caprolactam, and the specific number can be set to ≥3. The distance between two adjacent liquid atomizing nozzles is the same, that is, all atomizing nozzles are distributed in a regular polygon to ensure that the caprolactam is evenly distributed in the vaporization mixer after atomization. Step 2: Ammonia gas is preheated to 300-400℃. The preheated ammonia gas enters the first ammonia inlet 7 and the second ammonia inlet 13 through the high-temperature ammonia gas pipeline 17, and further enters the large annular gas distributor 4 and the small annular gas distributor 5, respectively. Finally, it enters the shell 1 through the first vent 14 and the second vent 15. Caprolactam spray comes into countercurrent contact with the ammonia gas, causing the caprolactam to vaporize. The feed molar ratio of ammonia gas to caprolactam is 1:1-10. Step 3: The vaporized mixed gas passes through the liquid trap 2 to collect unvaporized droplets and then enters the subsequent reactor for reaction through the mixed gas outlet 9. Step 4: Unvaporized droplets and a small amount of tar generated during the vaporization process are collected at the bottom of the shell 1 through the liquid trap 2 and discharged in appropriate amounts through the unvaporized liquid outlet according to the actual operating conditions such as liquid level and temperature. This invention can effectively reduce the production of tar and carbon deposits by caprolactam during gasification, and prevent them from covering the catalyst surface and reducing catalyst activity in subsequent reactions, thus laying the foundation for long-term stable operation of the system and improving product yield.

[0039] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model.

Claims

1. A vaporization mixing apparatus for the gas-phase preparation of 6-aminohexanonitrile, the vaporization mixing apparatus comprising a shell (1), characterized in that: The top of the shell (1) is provided with a mixed gas outlet (9); the bottom of the shell (1) is provided with an unvaporized liquid outlet (8); the upper inner part of the shell (1) is provided with a liquid collection unit, the lower part of the liquid collection unit is provided with an annular liquid distributor (3) for caprolactam feeding, the lower part of the annular liquid distributor (3) is provided with an ammonia feeding unit; the ammonia feeding unit includes at least a large annular gas distributor (4) for making ammonia rise along the inner wall of the shell (1).

2. The vaporization mixing apparatus for the gas-phase preparation of 6-aminohexanonitrile according to claim 1, characterized in that: The large annular gas distributor (4) has several first vent holes (14) evenly distributed on its upper part. The first vent holes (14) are located on the outer side near the axis and are located at an angle of θ1 with the axis, where 0° < θ1 ≤ 90°.

3. The vaporization mixing apparatus for the gas-phase preparation of 6-aminohexanonitrile according to claim 1, characterized in that: The ratio of the outer diameter of the large annular gas distributor (4) to the inner diameter of the shell (1) is 1:1 to 2.

4. The gasification mixing apparatus for the gas-phase preparation of 6-aminohexanonitrile according to claim 1, characterized in that: The ammonia feeding unit also includes a small annular gas distributor (5), and a number of second vent holes (15) are evenly distributed on the upper part of the small annular gas distributor (5). The second vent holes (15) are set at a position with an angle of θ2 with the axis, -45°<θ2≤45°; The ratio of the outer diameter of the small annular gas distributor (5) to the inner diameter of the shell (1) is 1:2 to 5.

5. The vaporization mixing apparatus for the gas-phase preparation of 6-aminohexanonitrile according to claim 4, characterized in that: The large annular gas distributor (4) is located on the side close to the annular liquid distributor (3), and the small annular gas distributor (5) is located at the lower part of the large annular gas distributor (4). Atomizing nozzles (10) are evenly distributed at the bottom of the annular liquid distributor (3).

6. The vaporization mixing apparatus for the gas-phase preparation of 6-aminohexanonitrile according to claim 4, characterized in that: The outer diameter of the small annular gas distributor (5) is larger than the outer diameter of the annular liquid distributor (3).

7. A vaporization mixing apparatus for the gas-phase preparation of 6-aminohexanonitrile according to claim 5, characterized in that: The annular liquid distributor (3) has caprolactam inlets (6) symmetrically arranged on both sides, and the two caprolactam inlets (6) are respectively connected to the preheated caprolactam liquid phase pipeline (16).

8. A vaporization mixing apparatus for the gas-phase preparation of 6-aminohexanonitrile according to claim 5, characterized in that: The large annular gas distributor (4) has a first ammonia inlet (7) symmetrically arranged on both sides, and the small annular gas distributor (5) has a second ammonia inlet (13) symmetrically arranged on both sides. The first ammonia inlet (7) and the second ammonia inlet (13) are respectively connected to the high-temperature ammonia pipeline (17).

9. A vaporization mixing apparatus for the gas-phase preparation of 6-aminohexanonitrile according to claim 1, characterized in that: The liquid trapping unit includes at least three layers of liquid traps (2) arranged from top to bottom. The liquid trap (2) includes a circular perforated plate (12) located in the middle, and a number of rectangular baffles (11) are evenly distributed on the outer circumference of the circular perforated plate (12); The annular liquid distributor (3) is positioned at the corresponding position at the bottom center of the liquid collector (2); the ratio of the outer diameter of the circular orifice plate (12) to the inner diameter of the shell (1) is 1:2 to 5.

10. A vaporization mixing apparatus for the gas-phase preparation of 6-aminohexanonitrile according to claim 9, characterized in that: One end of the rectangular baffle (11) is connected to the inner wall of the shell (1), and the other end of the rectangular baffle (11) is connected to the outer wall of the circular perforated plate (12); the rectangular baffle (11) is inclined and its angle with the vertical direction is 45°.

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