Liquid ammonia gasification system for pyridine production

Abstract

The utility model discloses a liquid ammonia gasification system for pyridine production, which belongs to liquid ammonia gasification equipment, aims to solve the technical problems of improving liquid ammonia gasification efficiency and reducing steam consumption in the pyridine production process, and adopts the technical scheme that the liquid ammonia gasification system comprises an ammonia preheater, an ammonia vaporizer, a spiral plate heat exchanger and an ammonia drainage tank, the tube pass inlet end of the ammonia preheater is communicated with a high-temperature crude pyridine product inlet pipeline, and the tube pass outlet end of the ammonia preheater is communicated with a low-temperature pyridine outlet pipeline; a shell pass outlet end of the ammonia preheater is communicated with an ammonia gas outlet pipeline, a shell pass inlet end of the ammonia preheater is communicated with a liquid ammonia pipeline, one path of the liquid ammonia pipeline is communicated to a shell pass of the ammonia preheater, the other path of the liquid ammonia pipeline is provided with a liquid ammonia standby pipeline, and the liquid ammonia standby pipeline is communicated to an ammonia vaporizer after being converged with the ammonia gas outlet pipeline. The tube pass of the ammonia vaporizer is communicated with a steam pipeline, the ammonia vaporizer is communicated with the spiral-plate heat exchanger through a vaporized ammonia outlet pipeline, and the spiral-plate heat exchanger is provided with a steam residual liquid inlet pipeline.

Description

Technical Field

[0001] The utility model relates to liquid ammonia gasification equipment, in particular to a liquid ammonia gasification system for pyridine production. Background Art

[0002] Pyridine can be obtained from natural coal tar, but coal tar only contains about 0.1% of pyridine and needs to go through multiple fractionations, with low efficiency. Currently, pyridine is mainly obtained through chemical synthesis. Pyridine and its derivatives are more stable than benzene, and their reactivity is similar to that of nitrobenzene. Typical aromatic electrophilic substitution reactions occur at the 3- and 5-positions, but the reactivity is lower than that of benzene, and generally, it is not easy to undergo nitration, halogenation, sulfonation and other reactions. Pyridine has basicity and can react with acids to form salts.

[0003] Pyridine can be used as a solvent, denaturant, auxochrome, and raw material for synthesizing a series of products in industry, including pharmaceuticals (such as vitamin B3, vitamin B6, isoniazid, etc.), disinfectants, dyes, food flavorings, adhesives, explosives, etc. Derivatives of pyridine widely exist in nature, and some of them are essential active ingredients for organisms, such as vitamin B3 (niacin and nicotinamide) and vitamin B6 (pyridoxine, pyridoxal, and pyridoxamine).

[0004] In the process of pyridine production, currently, steam is used to heat and gasify liquid ammonia, and circulating water is used to cool the produced crude materials. These two processes did not interfere with each other before, resulting in a large consumption of steam and circulating water in the system. Using a single ammonia vaporizer has a large load, and a heat source is required to heat and gasify ammonia. Generally, steam is usually used for heating. The greater the steam flow rate, the greater the demand for steam for a larger ammonia gasification amount. Therefore, the load on the equipment is also greater. A single ammonia vaporizer has an unsatisfactory gasification effect, a large consumption of steam energy, and incomplete gasification with liquid entrainment in the gaseous ammonia. A single ammonia vaporizer has a low gasification efficiency.

[0005] Therefore, in the process of pyridine production, how to improve the liquid ammonia gasification efficiency and reduce steam consumption is a technical problem that needs to be solved urgently at present. Summary of the Invention

[0006] The technical task of the utility model is to provide a liquid ammonia gasification system for pyridine production to solve the problem of how to improve the liquid ammonia gasification efficiency and reduce steam consumption in the process of pyridine production.

[0007] The technical task of the present utility model is achieved in the following manner. A liquid ammonia gasification system for pyridine production includes an ammonia preheater, an ammonia vaporizer, a spiral plate heat exchanger, and an ammonia drain tank. The inlet end of the tube side of the ammonia preheater is connected to a high-temperature crude pyridine inlet pipeline, and the outlet end of the tube side of the ammonia preheater is connected to a low-temperature pyridine outlet pipeline; the outlet end of the shell side of the ammonia preheater is connected to an ammonia gas outlet pipeline, and the inlet end of the shell side of the ammonia preheater is connected to a liquid ammonia pipeline. One path of the liquid ammonia pipeline is connected to the shell side of the ammonia preheater, and another path of the liquid ammonia pipeline is provided with a liquid ammonia standby pipeline. The liquid ammonia standby pipeline converges with the ammonia gas outlet pipeline and then is connected to the ammonia vaporizer. The tube side of the ammonia vaporizer is connected to a steam pipeline, and the ammonia vaporizer is connected to the spiral plate heat exchanger through a vaporized ammonia outlet pipeline. A steam residue inlet pipeline is provided on the spiral plate heat exchanger, and the steam residue inlet pipeline is connected to the spiral plate heat exchanger through an inlet manual valve two. The spiral plate heat exchanger is connected to the ammonia drain tank through the ammonia gas outlet pipeline.

[0008] Preferably, a self-adjusting valve one is provided on the high-temperature crude pyridine inlet pipeline; a total liquid ammonia cut-off valve, a remote transmission flowmeter one, a self-adjusting valve two, and an inlet manual valve one are sequentially provided on the liquid ammonia pipeline; a liquid ammonia outlet valve is provided on the liquid ammonia standby pipeline; an outlet manual valve one, a remote transmission thermometer two, and a pressure gauge one are sequentially provided on the ammonia gas outlet pipeline.

[0009] Preferably, a low-temperature pyridine outlet pipeline is provided on the ammonia preheater, and a low-temperature pyridine outlet valve is provided on the low-temperature pyridine outlet pipeline.

[0010] Preferably, a pipeline pressure protection pipeline is provided on the ammonia gas outlet pipeline. A safety valve one and a safety valve two are provided on the pipeline pressure protection pipeline, and the pipeline pressure protection pipeline is connected to the total tail gas pipeline. A safety valve four is provided on the pipeline connecting the total tail gas pipeline and the ammonia drain tank, and a safety valve five is provided on the pipeline connecting the total tail gas pipeline and the spiral plate heat exchanger.

[0011] Preferably, a drain valve three and a drain valve four are symmetrically provided on one side of the ammonia vaporizer;

[0012] A drain valve one and a drain valve two are respectively provided on both sides of the ammonia preheater.

[0013] Preferably, a self-adjusting valve three and a remote transmission thermometer one are provided on the steam pipeline; a safety valve three is provided on the vaporized ammonia outlet pipeline, and the lower end of the ammonia vaporizer is connected to a residue to steam recovery pipeline.

[0014] Preferably, an inlet manual valve three is provided on the ammonia gas outlet pipeline;

[0015] An ammonia vaporizer and heat exchanger balance pipeline is provided on the ammonia gas outlet pipeline, and an outlet manual valve two is provided on the ammonia vaporizer and heat exchanger balance pipeline;

[0016] An outlet manual valve IV and a pressure gauge II are provided on the pipeline where the residual liquid goes to the steam recovery pipeline and is connected to the spiral plate heat exchanger.

[0017] Preferably, a safety valve II is provided on the pipeline where the ammonia drainage tank is connected to the spiral plate heat exchanger. The safety valve II is used to protect the pressure safety of the spiral plate heat exchanger and related pipelines.

[0018] Preferably, an ammonia regulating valve I is provided on the ammonia outlet pipeline, and a remote pressure gauge II is provided between the ammonia outlet pipeline and the high-temperature crude pyridine inlet pipeline.

[0019] More preferably, a pipeline for heated gaseous ammonia to the system is provided at the upper end of the ammonia drainage tank. An ammonia regulating valve II, an ammonia flowmeter, a pressure gauge III, a remote pressure gauge III and an ammonia remote thermometer are provided on the pipeline for heated gaseous ammonia to the system; a pipeline for recycling within the system is provided at the lower end of the ammonia drainage tank. A liquid level gauge and an ammonia water regulating valve are provided on the pipeline between the pipeline for recycling within the system and the ammonia drainage tank.

[0020] The liquid ammonia gasification system for pyridine production of the present utility model has the following advantages:

[0021] (1) By adopting a multi-stage series and step-by-step heating gasification process, the present utility model improves the ammonia gasification efficiency, reduces the equipment load, effectively reduces the steam consumption, and at the same time reduces the temperature of the output material, which is safe, economical and practical;

[0022] (2) The present utility model separately feeds liquid ammonia and the produced crude material into the liquid ammonia preheater, so that the liquid ammonia exchanges heat with the high-temperature crude material just produced in the system for the first time (primary gasification), and there is no need for steam and circulating water to heat the gaseous ammonia and cool the crude material respectively, greatly utilizing the heat energy generated within the system;

[0023] (3) The present utility model feeds the liquid ammonia-containing gaseous ammonia in the liquid ammonia preheater into the ammonia vaporizer for complete gasification (secondary gasification); since most of the liquid ammonia has been gasified in the previous step, a large amount of heat is no longer required; in this step, the 1.5MPa steam previously used is changed to 0.5MPa steam with a lower temperature and pressure, reducing the steam energy consumption, reducing the cost and reducing the equipment load;

[0024] (4) The present utility model feeds the completely gasified gaseous ammonia into the spiral plate heat exchanger for gasification and temperature increase (tertiary gasification), and uses the condensate in the steam condensate pipe network to exchange heat with the completely gasified but not very hot gaseous ammonia, further increasing the temperature of the gaseous ammonia and further condensing the steam residual liquid; increasing the temperature of the gaseous ammonia entering the system, no longer requiring separate heating of the gaseous ammonia, reducing the energy consumption cost, further condensing the steam residual liquid and effectively utilizing the heat energy in the steam residual liquid, improving the energy utilization efficiency;

[0025] (5) The utility model sends the gas ammonia after gasification and temperature increase into the ammonia drain tank for ammonia drainage treatment, separates the gasified gas ammonia, ensures that the gas ammonia enters the reaction system for reaction without liquid, and ensures the safety of the device and process; finally, the completely separated gas ammonia in the ammonia drain tank is sent into the production reaction system.

[0026] Therefore, the utility model has the characteristics of reasonable design, simple structure, easy processing, small volume, convenient use, multi-purpose, etc. Therefore, it has good popularization and application value. Brief Description of the Drawings

[0027] The following further describes the utility model with reference to the drawings.

[0028] Appendix Figure 1 It is a structural schematic diagram of a liquid ammonia gasification system for pyridine production.

[0029] In the figure: 1. Ammonia preheater, 2. Ammonia vaporizer, 3. Spiral plate heat exchanger, 4. Ammonia drain tank, 5. Total liquid ammonia cut-off valve, 6. Remote flowmeter I, 7. Self-regulating valve II, 8. Liquid ammonia outlet valve, 9. Remote thermometer II, 10. Pressure gauge I, 11. Remote pressure gauge II, 12. Self-regulating valve I, 13. Outlet manual valve I, 14. Inlet manual valve I, 15. Safety valve II, 16. Safety valve I, 17. Low-temperature pyridine outlet valve, 18. Drain valve I, 19. Drain valve II, 20. Drain valve IV, 21. Drain valve III, 22. Self-regulating valve III, 23. Remote thermometer I, 24. Outlet manual valve II, 25. Inlet manual valve III, 26. Inlet manual valve II, 27. Outlet manual valve IV, 28. Pressure gauge II, 29. Safety valve V, 30. Ammonia gas regulating valve I, 31. Remote pressure gauge III, 32. Pressure gauge III, 33. Safety valve IV, 34. Ammonia gas flowmeter, 35. Ammonia gas regulating valve II, 36. Ammonia gas remote thermometer, 37. Liquid level gauge, 38. Ammonia water regulating valve, 39. Safety valve III, 40. High-temperature pyridine crude product inlet pipeline, 41. Ammonia gas outlet pipeline, 42. Pipeline pressure protection pipeline, 43. Ammonia vaporizer and heat exchanger balance pipeline, 44. Liquid ammonia pipeline, 45. Liquid ammonia standby pipeline, 46. Steam pipeline, 47. Gasified ammonia outlet pipeline, 48. Residual liquid to steam recovery pipeline, 49. Steam residual liquid inlet pipeline, 50. Pipeline for recycling within the system, 51. Ammonia gas outlet pipeline, 52. Pipeline to the tail gas main pipeline, 53. Pipeline for heated gas ammonia to the system, 54. Low-temperature pyridine outlet pipeline. Specific Embodiments

[0030] The following makes a detailed description of a liquid ammonia gasification system for pyridine production of the utility model with reference to the attached drawings and specific embodiments.

[0031] In the description of the present utility model, it should be understood that the orientation or positional relationships indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present utility model and simplifying the description. Instead of indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, it cannot be construed as a limitation of the present utility model. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0032] In the description of the present utility model, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0033] Embodiment:

[0034] As shown Figure 1 in the attached drawings, a liquid ammonia gasification system for pyridine production according to the present utility model has a structure including an ammonia preheater 1, an ammonia vaporizer 2, a spiral plate heat exchanger 3, and an ammonia drain tank 4. The tube-side inlet end of the ammonia preheater 1 is connected to a high-temperature crude pyridine inlet pipeline 40, and the tube-side outlet end of the ammonia preheater 1 is connected to a low-temperature pyridine outlet pipeline 54; the shell-side outlet end of the ammonia preheater 1 is connected to an ammonia gas outlet pipeline 41, and the shell-side inlet end of the ammonia preheater 1 is connected to a liquid ammonia pipeline 44. One path of the liquid ammonia pipeline 44 is connected to the shell side of the ammonia preheater 1, and the other path of the liquid ammonia pipeline 44 is connected to a liquid ammonia standby pipeline 45. The liquid ammonia standby pipeline 45 and the ammonia gas outlet pipeline 41 converge and are then connected to the ammonia vaporizer 2. The tube side of the ammonia vaporizer 2 is connected to a steam pipeline 46. The ammonia vaporizer 2 is connected to the spiral plate heat exchanger 3 through a vaporized ammonia outlet pipeline 47. A steam residue inlet pipeline 49 is installed on the spiral plate heat exchanger 3. The steam residue inlet pipeline 19 is connected to the spiral plate heat exchanger 3 through an inlet manual valve II 26. The spiral plate heat exchanger 3 is connected to the ammonia drain tank 4 through an ammonia gas outlet pipeline 51.

[0035] An automatic control valve I 12 is installed on the high-temperature crude pyridine inlet pipeline 40 in this embodiment; a total liquid ammonia cut-off valve 5, a remote flowmeter I 6, an automatic control valve II 7, and an inlet manual valve I 14 are successively installed on the liquid ammonia pipeline 44; a liquid ammonia outlet valve 8 is installed on the liquid ammonia standby pipeline 45; an outlet manual valve I 13, a remote thermometer II 9, and a pressure gauge I 10 are successively installed on the ammonia gas outlet pipeline 51.

[0036] In this embodiment, a low-temperature pyridine outlet pipeline 54 is installed on the ammonia preheater 1, and a low-temperature pyridine outlet valve 17 is installed on the low-temperature pyridine outlet pipeline 54.

[0037] In this embodiment, a pipeline pressure protection pipeline 42 is installed on the ammonia outlet pipeline 51. A safety valve I 16 and a safety valve II 15 are installed on the pipeline pressure protection pipeline 42, and the pipeline pressure protection pipeline 42 is connected to the exhaust gas main pipeline 52. A safety valve IV 33 is installed on the pipeline connecting the exhaust gas main pipeline 52 and the ammonia drainage tank 4, and a safety valve V 29 is installed on the pipeline connecting the exhaust gas main pipeline 52 and the spiral plate heat exchanger 3.

[0038] In this embodiment, a drain valve III 21 and a drain valve IV 20 are symmetrically installed on one side of the ammonia vaporizer 2; a drain valve I 18 and a drain valve II 19 are respectively installed on both sides of the ammonia preheater 1.

[0039] In this embodiment, a self-adjusting valve III 22 and a remote thermometer I 23 are installed on the steam pipeline 46; a safety valve III 39 is installed on the vaporized ammonia outlet pipeline 47, and a residual liquid to steam recovery pipeline 48 is connected to the lower end of the ammonia vaporizer 2.

[0040] In this embodiment, an inlet manual valve III 25 is installed on the ammonia outlet pipeline 51; an ammonia vaporizer and heat exchanger balance pipeline 43 is installed on the ammonia outlet pipeline 51, and an outlet manual valve II 24 is installed on the ammonia vaporizer and heat exchanger balance pipeline 43; an outlet manual valve IV 27 and a pressure gauge II 28 are installed on the pipeline connecting the residual liquid to steam recovery pipeline 48 and the spiral plate heat exchanger 3.

[0041] In this embodiment, a safety valve II 29 is installed on the pipeline connecting the ammonia drainage tank 4 and the spiral plate heat exchanger 3, and the safety valve II 29 is used to protect the spiral plate heat exchanger 3 and the related pipeline pressure safety.

[0042] In this embodiment, an ammonia regulating valve I 30 is installed on the ammonia outlet pipeline 51, and a remote pressure gauge II 11 is installed between the ammonia outlet pipeline 51 and the high-temperature pyridine crude product inlet pipeline 40.

[0043] In this embodiment, a heated gaseous ammonia to system pipeline 53 is installed at the upper end of the ammonia drainage tank 4. An ammonia regulating valve II 35, an ammonia flowmeter 34, a pressure gauge III 32, a remote pressure gauge III 31 and an ammonia remote thermometer 36 are installed on the heated gaseous ammonia to system pipeline 53; a pipeline for recycling within the system 50 is installed at the lower end of the ammonia drainage tank 4, and a liquid level gauge 37 and an ammonia water regulating valve 38 are installed on the pipeline between the pipeline for recycling within the system 50 and the ammonia drainage tank 4.

[0044] The working process of this embodiment is specifically as follows:

[0045] The high-temperature crude material produced enters the tube side of the ammonia preheater 1 after adjusting the flow rate through the self-regulating valve 12. At the same time, liquid ammonia passes through the main liquid ammonia cut-off valve 5, the remote transmission flowmeter 6, the self-regulating valve 2 7 and the inlet manual valve 14, and enters the shell side of the ammonia preheater 1. The two materials exchange heat by means of the high temperature difference. After heat exchange, the temperature of the crude material decreases and enters the system storage tank. If there is a problem with the ammonia preheater 1, it will be cut out of the system in time through the liquid ammonia outlet valve 8, and the liquid ammonia can directly enter the ammonia vaporizer 2 for heat exchange; while the temperature of the liquid ammonia rises after heat exchange and passes through the outlet manual valve 13, and is monitored by the remote transmission thermometer 2 9, and enters the tube side of the ammonia vaporizer 2. The safety valve 2 15 and the safety valve 1 16 are pressure protection devices for protecting the ammonia preheater 1 and the pipeline; a stream of steam passes through the self-regulating valve 3 22 and enters the ammonia vaporizer 2, and the remote transmission thermometer 1 23 is interlocked with the self-regulating valve 3 22 to ensure that the steam inlet volume provides heat source for sufficient ammonia gasification. The residual liquid after heat exchange returns to the pipeline for centralized utilization in the system for recycling; at this time, the ammonia is completely gasified, and a safety valve 3 39 is added to the gasified ammonia outlet pipeline 47 to protect the normal pressure of the equipment and the pipeline. The gaseous ammonia will continue to enter the spiral plate heat exchanger 3 for heating up. The steam residual liquid provides heat source for heating up. It enters the spiral plate heat exchanger 3 from the inlet manual valve 2 26 and exits from the outlet manual valve 2 24. The residual liquid after heat exchange is recycled. The pressure gauge 2 28 indicates the working pressure of the spiral plate heat exchanger 3. The heated gaseous ammonia passes through the inlet manual valve 3 25 and enters the ammonia drain tank 4 through the ammonia gas regulating valve 1 30. The safety valve 2 29 protects the pressure safety of the spiral plate heat exchanger 3 and the related pipelines; among them, the pressure remote transmitter 2 11 is interlocked with the self-regulating valve 12 to ensure the balance between the gasified ammonia and the liquid ammonia entering the system within the normal index range. After the gaseous ammonia enters the ammonia drain tank 4, the entrained liquid will remain in the ammonia drain tank 4. The safety valve 4 33 protects the normal pressure of the ammonia drain tank 4. The gaseous ammonia will react through the ammonia gas flowmeter 34, the ammonia gas remote transmission thermometer 36 and the ammonia gas regulating valve 2 35. And the un-gasified ammonia water will be recycled through the liquid level gauge 37 and the ammonia water regulating valve 38.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A liquid ammonia gasification system for pyridine production, characterized in that: The system comprises an ammonia preheater, an ammonia vaporizer, a spiral plate heat exchanger and an ammonia drain tank. The tube side inlet end of the ammonia preheater is connected with a high-temperature crude pyridine inlet pipeline, and the tube side outlet end of the ammonia preheater is connected with a low-temperature pyridine outlet pipeline; the shell side outlet end of the ammonia preheater is connected with an ammonia outlet pipeline, the shell side inlet end of the ammonia preheater is connected with a liquid ammonia pipeline, one side of the liquid ammonia pipeline is connected to the shell side of the ammonia preheater, and the other side of the liquid ammonia pipeline is provided with a liquid ammonia standby pipeline, the liquid ammonia standby pipeline and the ammonia outlet pipeline are connected to the ammonia vaporizer after being converged, the tube side of the ammonia vaporizer is connected with a steam pipeline, the ammonia vaporizer is connected to the spiral plate heat exchanger through the vaporized ammonia outlet pipeline, a steam residual liquid inlet pipeline is provided on the spiral plate heat exchanger, the steam residual liquid inlet pipeline is connected to the spiral plate heat exchanger through an inlet manual valve 2, and the spiral plate heat exchanger is connected to the ammonia drain tank through the ammonia outlet pipeline.

2. The liquid ammonia gasification system for pyridine production according to claim 1, characterized in that: The high-temperature pyridine crude product inlet pipeline is provided with a self-regulating valve 1; the liquid ammonia pipeline is provided with a total liquid ammonia cut-off valve, a remote flow meter 1, a self-regulating valve 2 and an inlet manual valve 1 in sequence; the liquid ammonia standby pipeline is provided with a liquid ammonia outlet valve; the ammonia gas outlet pipeline is provided with an outlet manual valve 1, a remote thermometer 2 and a pressure gauge 1 in sequence.

3. The liquid ammonia gasification system for pyridine production according to claim 1, characterized in that: The ammonia preheater is provided with a low-temperature pyridine outlet pipeline, and the low-temperature pyridine outlet pipeline is provided with a low-temperature pyridine outlet valve.

4. The liquid ammonia gasification system for pyridine production according to claim 1, characterized in that: A pipeline pressure protection pipeline is arranged on the ammonia outlet pipeline, safety valve one and safety valve two are arranged on the pipeline pressure protection pipeline, and the pipeline pressure protection pipeline is connected to the exhaust gas main pipeline, a safety valve four is arranged on the pipeline connecting the exhaust gas main pipeline and the ammonia drain tank, and a safety valve five is arranged on the pipeline connecting the exhaust gas main pipeline and the spiral plate heat exchanger.

5. The liquid ammonia gasification system for pyridine production according to claim 1, characterized in that: A third and a fourth drain valve are symmetrically arranged on one side of the ammonia vaporizer; A first drain valve and a second drain valve are respectively arranged on both sides of the ammonia preheater.

6. The liquid ammonia gasification system for pyridine production according to claim 1, characterized in that: The steam pipeline is provided with a self-regulating valve three and a remote thermometer one; the vaporized ammonia outlet pipeline is provided with a safety valve three, and the lower end of the ammonia vaporizer is connected with a residual liquid steam recovery pipeline.

7. The liquid ammonia gasification system for pyridine production according to claim 1, characterized in that: The ammonia outlet pipeline is provided with an inlet manual valve three; The ammonia outlet pipeline is provided with an ammonia vaporizer and a heat exchanger balance pipeline, and an outlet manual valve 2 is provided on the ammonia vaporizer and the heat exchanger balance pipeline; An outlet manual valve 4 and a pressure gauge 2 are arranged on the pipeline connecting the residual liquid steam recovery pipeline and the spiral plate heat exchanger.

8. The liquid ammonia gasification system for pyridine production according to claim 1, characterized in that: A second safety valve is provided on the pipeline connecting the ammonia drain tank and the spiral plate heat exchanger, and the second safety valve is used to protect the pressure safety of the spiral plate heat exchanger and related pipelines.

9. The liquid ammonia gasification system for pyridine production according to claim 1, characterized in that: An ammonia regulating valve 1 is arranged on the ammonia outlet pipeline, and a remote pressure gauge 2 is arranged between the ammonia outlet pipeline and the high-temperature pyridine crude product inlet pipeline.

10. The liquid ammonia gasification system for pyridine production according to any one of claims 1 to 9, characterized in that: The upper end of the ammonia drain tank is provided with a heated gas ammonia removal system pipeline, and the heated gas ammonia removal system pipeline is provided with an ammonia regulating valve 2, an ammonia flow meter, a pressure gauge 3, a remote pressure gauge 3 and an ammonia remote thermometer; the lower end of the ammonia drain tank is provided with a system recycling pipeline, and a liquid level meter and an ammonia regulating valve are provided on the pipeline between the system recycling pipeline and the ammonia drain tank.

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