Production device for preparing 6-aminocapronitrile crude product by gas phase method
By using countercurrent contact gasification of caprolactam and liquid ammonia and heat recovery, the problem of catalyst coking was solved, product yield and system stability were improved, and energy consumption and costs were reduced.
Patent Information
- Application Number
- CN202520139951.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-20
- Publication Date
- 2025-12-30
- Estimated Expiration
- 2035-01-20
AI Technical Summary
In the existing gas-phase method for preparing crude 6-aminohexanonitrile, uneven heating of the catalyst can lead to the formation of tar and carbon deposits, reducing product yield and affecting system stability.
The caprolactam and liquid ammonia are preheated separately and then contacted in a countercurrent manner to ensure that they are fully vaporized in the vaporizer. Energy consumption is reduced through a heat recovery unit, and an ammonia dehydration section is set up to achieve ammonia reuse.
It improved product yield, enhanced system stability, and reduced production costs and energy consumption.
Smart Images
Figure CN223732737U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model belongs to 6 - amino hexanitrile crude production technical field, concretely is a kind of production device of gas phase method preparation 6 - amino hexanitrile crude. BACKGROUND
[0002] Hexamethylenediamine as an important chemical, mainly used for producing polyamide, also can be used for synthesis polyurethane resin, ion exchange resin and diisocyanate, and used as urea-formaldehyde resin, epoxy resin etc. Curing agent, organic crosslinking agent etc., also can be used as adhesive, stabilizer, bleaching agent, anticorrosive agent etc., in organic synthesis, aerospace, textile papermaking, metal material etc. Field has wide application. Hexamethylenediamine can be prepared by 6-amino hexanitrile hydrogenation, the synthesis of 6-amino hexanitrile mainly takes caprolactam as raw material at present, is prepared after ammoniation dehydration reaction, including two major categories of gas phase method and liquid phase method;6-amino hexanitrile crude product is needed when gas phase method is used to produce 6-amino hexanitrile, and catalyst reaction is used to synthesize, reactor temperature is higher, and caprolactam is easy to produce tar, carbon deposition in the process of gasification and cover on the surface of catalyst, cause catalyst active site to reduce;The above process not only causes the yield of product to be greatly reduced finally, but also causes catalyst to be gradually deactivated, thereby causing the running stability of the whole system to be poor. CONTENT OF UTILITY MODEL
[0003] In order to make up for the above insufficient, the utility model provides a kind of production device of gas phase method preparation 6-amino hexanitrile crude to solve the technical problems existing in prior art.
[0004] The technical scheme that the utility model solves its technical problem is as follows:
[0005] A kind of production device of gas phase method preparation 6-amino hexanitrile crude, including caprolactam storage tank and liquid ammonia pipeline, the caprolactam storage tank is connected with the upper inlet of vaporizer by caprolactam preheating unit, liquid ammonia pipeline is connected with the bottom inlet of vaporizer by liquid ammonia preheating unit, the gas phase outlet of vaporizer top is connected with reactor, and reactor is connected with crude 6-amino hexanitrile storage tank by heat recovery unit;The upper inlet of vaporizer is connected with annular liquid distributor arranged in the upper portion of vaporizer, and the bottom inlet of vaporizer is connected with gas phase distributor arranged in the bottom portion of vaporizer.
[0006] The utility model has the advantages that: the utility model is heated to caprolactam by caprolactam preheating unit, liquid ammonia is heated using liquid ammonia preheating unit, after the above-mentioned caprolactam and liquid ammonia are heated, annular liquid distributor and gas phase distributor are used to realize the countercurrent contact of the two, so that caprolactam is fully gasified, and coking when caprolactam contacts high-temperature equipment is effectively avoided;So as to reach the characteristics of improving product yield and system running stability.
[0007] The caprolactam preheating unit comprises a first heater and a second heater, and the caprolactam storage tank is connected to the inlet of the annular liquid distributor through the first heat exchange channel of the first heater and the first heat exchange channel of the second heater.
[0008] Preferably, the liquid ammonia preheating unit comprises a liquid ammonia vaporizer, an ammonia first heater and an ammonia second heater, and the liquid ammonia pipeline is connected to the gas phase distributor through the liquid ammonia vaporizer, the first heat exchange channel of the ammonia first heater and the first heat exchange channel of the ammonia second heater.
[0009] Preferably, the heat recovery unit comprises a reactor inlet and outlet heat exchanger, the outlet of the reactor is connected to the second heat exchange channel of the reactor inlet and outlet heat exchanger and the second heat exchange channel of the second heater, and the gas phase outlet of the condenser is connected to the crude 6-aminocapronitrile storage tank; the gas phase outlet at the top of the vaporizer is connected to the top inlet of the reactor through the first heat exchange channel of the reactor inlet and outlet heat exchanger.
[0010] Preferably, the gas phase outlet of the condenser is connected to the inlet of the ammonia dehydration unit, the top gas phase outlet of the ammonia dehydration unit is connected to the inlet of the first heat exchange channel of the ammonia first heater through the ammonia buffer tank and the ammonia circulating compressor, and the bottom liquid phase outlet of the ammonia dehydration unit is connected to the wastewater pipeline.
[0011] Preferably, the ammonia dehydration unit is connected to the parallelly arranged ammonia dehydrators, the upper middle part of the ammonia dehydrators is provided with the inlet, the top of the ammonia dehydrators is provided with the gas phase outlet, and the bottom of the ammonia dehydrators is provided with the liquid phase outlet.
[0012] Preferably, the inlet of the second heat exchange channel of the first heater is connected to the first steam pipeline, and the outlet of the second heat exchange channel of the first heater is connected to the first condensate pipeline.
[0013] Preferably, the inlet of the second heat exchange channel of the ammonia first heater is connected to the second steam pipeline, and the outlet of the second heat exchange channel of the ammonia first heater is connected to the second condensate pipeline; the inlet of the second heat exchange channel of the ammonia second heater is connected to the heating oil inlet pipeline, and the outlet of the second heat exchange channel of the ammonia second heater is connected to the heating oil outlet pipeline.
[0014] An apparatus for preparing crude 6-aminohexanonitrile using a gas-phase method, manufactured according to the above technical solution, utilizes a stepped heating system to achieve a high temperature for ammonia gas, allowing for complete vaporization of caprolactam in the caprolactam vaporizer. This effectively prevents coking when caprolactam comes into contact with high-temperature equipment. By incorporating reactor inlet and outlet heat exchangers and a secondary heater, the apparatus fully utilizes the heat from the material after the reaction, effectively reducing energy consumption and production costs. Furthermore, the ammonia dehydration section enables the recovery and reuse of ammonia gas, further reducing production costs. The apparatus features a rational process design, reduced energy consumption and production costs, and achieves complete vaporization of caprolactam, laying the foundation for improved product yield and stable system operation. Attached Figure Description
[0015] 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.
[0016] Figure 1 This is a schematic diagram of the structure of this utility model.
[0017] In the diagram: 1. Liquid ammonia vaporizer; 2. Primary ammonia heater; 3. Secondary ammonia heater; 4. Vaporizer; 5. Secondary heater; 6. Crude 6-aminohexanonitrile condenser; 7. Crude 6-aminohexanonitrile storage tank; 8. Primary heater; 9. Ammonia circulating compressor; 10. Ammonia buffer tank; 11. Ammonia dehydrator; 12. Caprolactam storage tank; 13. Reactor inlet and outlet heat exchanger; 14. Reactor; 15. Liquid ammonia pipeline; 16. Annular liquid distributor; 17. Gas phase distributor; 18. Wastewater pipeline; 19. First steam pipeline; 20. First condensate pipeline; 21. Second steam pipeline; 22. Second condensate pipeline; 23. Heating oil inlet pipeline; 24. Heating oil outlet pipeline. Detailed Implementation
[0018] 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.
[0019] The following is in conjunction with the appendix Figure 1Further detailed description of the present application, the utility model relates to a kind of production device of 6-aminocapronitrile crude product prepared by gas phase method, including caprolactam storage tank 12 and liquid ammonia pipeline 15, the caprolactam storage tank 12 is connected by caprolactam preheating unit with the upper inlet of vaporizer 4, liquid ammonia pipeline 15 is connected by liquid ammonia preheating unit with the bottom inlet of vaporizer 4, the gas phase outlet of vaporizer 4 top is connected with reactor 14, reactor 14 is connected with crude 6-aminocapronitrile storage tank 7 by heat recovery unit;The upper inlet of vaporizer 4 is connected with annular liquid distributor 16 being arranged in the upper portion of vaporizer 4, and the bottom inlet of vaporizer 4 is connected with gas phase distributor 17 being arranged in the bottom portion of vaporizer 4.The utility model provides new gasification form, i.e. firstly caprolactam and liquid ammonia are preheated respectively, so that the temperature of liquid ammonia is in relatively high state;Subsequently, relatively high temperature gas ammonia and caprolactam are countercurrently contacted, and are fully mixed to realize the full gasification of caprolactam, finally, both enter reactor 14 to react, the above-mentioned mode can avoid that caprolactam gasification produces tar, carbon deposition in the reaction process, covers the surface of catalyst, to realize the characteristics of system stable operation and improve product yield, the utility model can realize the recovery of heat energy after reaction by setting heat recovery unit, while reducing the load of condensing device in subsequent process.
[0020] Further, the caprolactam preheating unit includes a first heater 8 and a second heater 5, and the caprolactam storage tank 12 is connected with the inlet of the annular liquid distributor 16 through the first heat exchange channel of the first heater 8 and the first heat exchange channel of the second heater 5. The utility model realizes the uniform distribution of caprolactam by heating caprolactam through the first heater 8 and the second heater 5 and making the heated caprolactam enter the vaporizer 4 through the annular liquid distributor 16, so as to facilitate the full mixing of caprolactam and gas ammonia in the later stage.
[0021] Further, the liquid ammonia preheating unit includes a liquid ammonia vaporizer 1, a first ammonia heater 2 and a second ammonia heater 3, and the liquid ammonia pipeline 15 is connected with the gas phase distributor 17 through the first heat exchange channel of the liquid ammonia vaporizer 1, the first heat exchange channel of the first ammonia heater 2 and the first heat exchange channel of the second ammonia heater 3. The utility model realizes the uniform distribution of gas ammonia by heating the vaporized liquid ammonia through the liquid ammonia vaporizer 1, the first ammonia heater 2 and the second ammonia heater 3 and making the heated gas ammonia enter the vaporizer 4 through the gas phase distributor 17, so as to facilitate the mixing of caprolactam and gas ammonia in the later stage and make caprolactam fully gasified.
[0022] Further, the heat recovery unit comprises a reactor feed and discharge heat exchanger 13, the outlet of the reactor 14 is connected with the second heat exchange channel of the reactor feed and discharge heat exchanger 13 and the second heat exchange channel of the secondary heater 5, and the liquid phase outlet of the crude 6-aminocapronitrile condenser 6 is connected with the crude 6-aminocapronitrile storage tank 7; the gas phase outlet at the top of the vaporizer 4 is connected with the top inlet of the reactor 14 through the first heat exchange channel of the reactor feed and discharge heat exchanger 13.
[0023] Further, the gas phase outlet of the crude 6-aminocapronitrile condenser 6 is connected with the inlet of the ammonia dehydration part, the top gas phase outlet of the ammonia dehydration part is connected with the first heat exchange channel inlet of the ammonia primary heater 2 through the ammonia buffer tank 10 and the ammonia circulating compressor 9, and the bottom liquid phase outlet of the ammonia dehydration part is connected with the waste water pipeline 18. The ammonia dehydration part can realize the recycling of ammonia, so as to reduce the production cost.
[0024] Further, the ammonia dehydration part is connected with the parallelly arranged ammonia dehydrator 11, the upper middle part of the ammonia dehydrator 11 is provided with an inlet, the top of the ammonia dehydrator 11 is provided with a gas phase outlet, and the bottom of the ammonia dehydrator 11 is provided with a liquid phase outlet.
[0025] Further, the inlet of the second heat exchange channel of the primary heater 8 is connected with the first steam pipeline 19, and the outlet of the second heat exchange channel of the primary heater 8 is connected with the first condensate pipeline 20.
[0026] Further, the inlet of the second heat exchange channel of the ammonia primary heater 2 is connected with the second steam pipeline 21, and the outlet of the second heat exchange channel of the ammonia primary heater 2 is connected with the second condensate pipeline 22; the inlet of the second heat exchange channel of the ammonia secondary heater 3 is connected with the heating oil inlet pipeline 23, and the outlet of the second heat exchange channel of the ammonia secondary heater 3 is connected with the heating oil outlet pipeline 24.
[0027] The working principle of the utility model is that: the raw material caprolactam in caprolactam storage tank 12 is heated by first heater 8 and second heater 5 respectively using steam and reacted material, the temperature is close to its boiling point temperature, then enters vaporizer 4 to gasify; the liquid ammonia in liquid ammonia pipeline 15 is gasified by liquid ammonia vaporizer 1, then enters ammonia first heater 2 and ammonia second heater 3 respectively using steam and heat conducting oil to heat, so that ammonia has high enough temperature, after entering vaporizer 4, caprolactam can be fully gasified; the gasified caprolactam and ammonia are uniformly mixed, after heat exchange by reactor inlet and outlet heat exchanger 13, enter reactor 14, under the action of catalyst, caprolactam generates 6-aminocapronitrile by ammoniation and dehydration reaction, the reacted material also contains unreacted caprolactam, ammonia and impurities generated by reaction, the reacted material is called crude 6-aminocapronitrile; the crude 6-aminocapronitrile is condensed in crude 6-aminocapronitrile condenser 6 after heat exchange by reactor inlet and outlet heat exchanger 13 and second heater 5, is stored in crude 6-aminocapronitrile storage tank 7 after condensation, prepares for entering subsequent refining purification section, the uncondensed ammonia is dehydrated in ammonia dehydrator 11 and returns to the inlet of ammonia first heater 2 after compression by ammonia circulating compressor 9 to recycle, the waste water removed by ammonia dehydrator 11 is discharged from the bottom.
[0028] The basic principle, main features and advantages of the present application are shown and described above. Those skilled in the art should understand that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application.
Claims
1. A plant for the production of 6-aminocapronitrile crude by the gas phase process, comprising a caprolactam tank (12) and a liquid ammonia conduit (15), characterized in that: The caprolactam storage tank (12) is connected with the upper inlet of the vaporizer (4) through a caprolactam preheating unit, the liquid ammonia pipeline (15) is connected with the bottom inlet of the vaporizer (4) through a liquid ammonia preheating unit, the gas phase outlet at the top of the vaporizer (4) is connected with the reactor (14), and the reactor (14) is connected with the crude 6-aminocapronitrile storage tank (7) through a heat recovery unit; The upper inlet of the vaporizer (4) is connected with an annular liquid distributor (16) arranged at the upper part of the vaporizer (4), and the bottom inlet of the vaporizer (4) is connected with a gas phase distributor (17) arranged at the bottom of the vaporizer (4).
2. The apparatus for preparing 6-aminocapronitrile crude by vapor phase method according to claim 1, characterized in that: The caprolactam preheating unit comprises a first heater (8) and a second heater (5), and the caprolactam storage tank (12) is connected with the inlet of the annular liquid distributor (16) through the first heat exchange channel of the first heater (8) and the first heat exchange channel of the second heater (5).
3. The apparatus for preparing 6-aminocapronitrile crude by vapor phase method according to claim 1, characterized in that: The liquid ammonia preheating unit comprises a liquid ammonia vaporizer (1), an ammonia gas first heater (2) and an ammonia gas second heater (3), and the liquid ammonia pipeline (15) is connected with the gas phase distributor (17) through the liquid ammonia vaporizer (1), the first heat exchange channel of the ammonia gas first heater (2) and the first heat exchange channel of the ammonia gas second heater (3).
4. The apparatus for preparing 6-aminocapronitrile crude by vapor phase method according to claim 2, characterized in that: The heat recovery unit comprises a reactor inlet and outlet heat exchanger (13), the outlet of the reactor (14) is connected with the second heat exchange channel of the reactor inlet and outlet heat exchanger (13) and the second heat exchange channel of the second heater (5), and the crude 6-aminocapronitrile condenser (6) is connected with the crude 6-aminocapronitrile storage tank (7); The gas phase outlet at the top of the vaporizer (4) is connected with the top inlet of the reactor (14) through the first heat exchange channel of the reactor inlet and outlet heat exchanger (13).
5. The apparatus for preparing 6-aminocapronitrile crude by vapor phase method according to claim 4, characterized in that: The gas phase outlet of the crude 6-aminocapronitrile condenser (6) is connected with the inlet of an ammonia gas dehydration part, the top gas phase outlet of the ammonia gas dehydration part is connected with the first heat exchange channel inlet of the ammonia gas first heater (2) through an ammonia gas buffer tank (10) and an ammonia gas circulating compressor (9), and the bottom liquid phase outlet of the ammonia gas dehydration part is connected with a waste water pipeline (18).
6. The apparatus for preparing 6-aminocapronitrile crude by vapor phase method according to claim 5, characterized in that: The ammonia gas dehydration part is connected with ammonia gas dehydrators (11) arranged in parallel, the upper middle part of the ammonia gas dehydrators (11) is provided with an inlet, the top of the ammonia gas dehydrators (11) is provided with a gas phase outlet, and the bottom of the ammonia gas dehydrators (11) is provided with a liquid phase outlet.
7. The apparatus for preparing 6-aminocapronitrile crude by vapor phase method according to claim 2, characterized in that: The inlet of the second heat exchange channel of the first heater (8) is connected with a first steam pipeline (19), and the outlet of the second heat exchange channel of the first heater (8) is connected with a first condensate pipeline (20).
8. The apparatus for preparing 6-aminocapronitrile crude by vapor phase method according to claim 3, characterized in that: The inlet of the second heat exchange channel of the ammonia gas first heater (2) is connected with a second steam pipeline (21), and the outlet of the second heat exchange channel of the ammonia gas first heater (2) is connected with a second condensate pipeline (22). The inlet of the second heat exchange channel of the ammonia gas second heater (3) is connected with a heating oil inlet pipeline (23), and the outlet of the second heat exchange channel of the ammonia gas second heater (3) is connected with a heating oil outlet pipeline (24).