Treatment system for reducing steam consumption in ammonia synthesis production process

By introducing hydrogen and nitrogen gas during ammonia synthesis and recycling, the problem of excessive steam consumption during ammonia synthesis is solved, the load of the steam turbine is reduced, and energy efficiency is improved.

CN119263302APending Publication Date: 2025-01-07FUJIAN EVERSUN TECH CO LTD
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Patent Information

Application Number
CN202411629469.1
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2024-11-15
Publication Date
2025-01-07

AI Technical Summary

Technical Problem

The steam consumption during ammonia synthesis production process is too high, resulting in excessive load on the turbine, affecting system efficiency and energy efficiency.

Method used

By introducing hydrogen and nitrogen into the ammonia synthesis supplementary gas pipeline and heat exchange module, the cold exchanger is used to recover the cold volume, and the recovered hydrogen and nitrogen are mixed and pressurized to reduce dependence on the turbine and steam consumption.

Benefits of technology

It effectively reduces steam consumption during ammonia synthesis production process, reduces the load of the steam turbine, and achieves energy-saving effects.

✦ Generated by Eureka AI based on patent content.

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Abstract

The invention relates to the technical field of chemical production, and particularly discloses a treatment system for reducing steam consumption in an ammonia synthesis production process, which is used for solving the problem of high energy consumption in the prior art. Comprising an ammonia synthesis make-up gas pipeline used for conveying hydrogen and nitrogen, an ammonia synthesis make-up gas valve is arranged on the ammonia synthesis make-up gas pipeline, the lower end of the ammonia synthesis make-up gas pipeline is connected with a gas compression module used for compressing gas, and the output end of the gas compression module is communicated with a heat exchange module through a hydrogen and nitrogen pipeline. Separated hydrogen and nitrogen are subjected to cold energy recovery through a synthetic gas inlet cold exchange pipeline and a cold exchanger, the recovered hydrogen and nitrogen enter a compressor high-pressure cylinder through a synthetic gas inlet compressor valve and a synthetic gas inlet compressor pipeline to be mixed with hydrogen and nitrogen sent by a compressor medium-pressure cylinder for pressurization, recycling is completed, resources are saved, and the production cost is reduced. The load of a steam turbine in the ammonia synthesis production process is reduced, and the energy-saving effect is achieved.
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Description

Technical Field

[0001] The invention relates to the technical field of chemical production, and in particular to a processing system for reducing steam consumption in an ammonia synthesis production process. Background Art

[0002] The fresh gas from the purification with a pressure of 3.0MPa and a temperature of 30℃ and the circulating gas returned from the synthesis loop are pressurized to 14.1MPa(A) by the compressor, and after heat exchange and temperature increase in the heat exchanger, they are sent to the ammonia synthesis tower. The synthesis gas reacts to generate NH3 under high temperature, high pressure and catalytic action of the catalyst. Then, it is cooled and condensed through the steam superheater, medium-pressure waste boiler, boiler feed water heater, low-pressure waste boiler, heat exchanger, water cooler, cold exchanger, primary ammonia cooler, and secondary ammonia cooler. Liquid ammonia is separated by the ammonia separator, and the product liquid ammonia is sent out of the boundary area. The unreacted gas returns to the circulation section of the synthesis gas compressor and merges with the fresh gas. After the pressure is increased, it continues to enter the synthesis tower for reaction.

[0003] At present, the temperature of the synthesis gas at the outlet of the water cooler is 40℃, which requires a large amount of liquid ammonia to be sent to the primary ammonia cooler and the secondary ammonia cooler for evaporation and cooling to ensure that the outlet temperature of the secondary ammonia cooler is below -10℃ and maintain the balance of the ammonia synthesis system reaction; the ammonia evaporated from the primary ammonia cooler and the secondary ammonia cooler needs to be pressurized and cooled by the ammonia ice machine, and the condensed liquid ammonia is sent to the liquid ammonia storage tank. The steam turbine of the ammonia ice machine requires 40t / h of 3.8MPa steam to maintain the balance of the ammonia system; the steam turbine of the synthesis gas compressor requires 52t / h of 9.8MPa steam to maintain the balance of the system reaction. Therefore, it is very necessary and meaningful to design a more efficient energy-saving treatment system to reduce the turbine load during the ammonia synthesis production process. Summary of the invention

[0004] The object of the present invention is to provide a processing system for reducing steam consumption in an ammonia synthesis production process, thereby solving the problems in the prior art.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A processing system for reducing steam consumption in an ammonia synthesis production process comprises an ammonia synthesis supplementary gas pipeline for conveying hydrogen and nitrogen, an ammonia synthesis supplementary gas valve being provided on the ammonia synthesis supplementary gas pipeline, a lower end of the ammonia synthesis supplementary gas pipeline being connected to a gas compression module for compressing gas, an output end of the gas compression module being communicated with a heat exchange module through a hydrogen and nitrogen pipeline, a compressor outlet valve being provided on the hydrogen and nitrogen pipeline, a first output end of the heat exchange module being communicated with a feed end of an ammonia synthesis tower through a hydrogen and nitrogen inlet ammonia synthesis tower pipeline, a second output end of the heat exchange module being communicated with a cooling module, the cooling module and the heat exchange module being interacted with a lithium bromide unit, a discharge end of the cooling module being communicated with a feed end of a liquid ammonia storage tank, and an ammonia discharge valve being provided on the pipeline between the liquid ammonia storage tank and an ammonia separator.

[0007] On the basis of the above technical solution, the present invention also provides the following optional technical solution:

[0008] In an optional scheme: the cooling module includes a water cooler, the discharge end of the water cooler is connected to a low-temperature water cooler, the discharge end of the low-temperature water cooler is connected to a cold exchanger, the discharge end of the cold exchanger is connected to a primary ammonia cooler, the discharge end of the primary ammonia cooler is connected to a secondary ammonia cooler, the discharge end of the secondary ammonia cooler is connected to an ammonia separator, the second discharge end of the primary ammonia cooler and the second secondary ammonia cooler is connected to a liquid ammonia storage tank through an ammonia pipeline for an ammonia cooler, the second discharge end of the primary ammonia cooler is provided with a primary ammonia cooler ammonia inlet valve, the second discharge end of the secondary ammonia cooler is provided with a secondary ammonia cooler ammonia inlet valve, and the ammonia pipeline for the ammonia cooler is provided with a liquid ammonia delivery valve.

[0009] In an optional scheme: the exhaust end of the first-level ammonia cooler is connected to the low-pressure cylinder of the ice machine through a low-pressure ammonia gas pipeline, and a low-pressure ammonia gas valve is provided on the low-pressure ammonia gas pipeline; the exhaust end of the second-level ammonia cooler is connected to the high-pressure cylinder of the ice machine through a medium-pressure ammonia gas pipeline, and a medium-pressure ammonia gas valve is provided on the medium-pressure ammonia gas pipeline; the high-pressure cylinder of the ice machine and the low-pressure cylinder of the ice machine are connected to the ice machine turbine for driving the ice machine to work; the discharge end of the low-pressure cylinder of the ice machine is connected to the feed end of the high-pressure cylinder of the ice machine through a pipeline; the discharge end of the high-pressure cylinder of the ice machine is connected to the ammonia ice machine water cooler through the ammonia gas pipeline, and an ice machine ammonia gas delivery valve is provided on the ammonia gas pipeline; the discharge end of the ammonia ice machine water cooler is connected to the feed end of the liquid ammonia storage tank, and an ice machine system ammonia delivery valve is provided on the pipeline between the ammonia ice machine water cooler and the liquid ammonia storage tank.

[0010] In an optional scheme: the heat exchange module includes a heat exchanger connected to the hydrogen and nitrogen pipeline and a steam superheater connected to the discharge end of the steam superheater, the steam superheater is connected to the ammonia synthesis tower through the synthesis gas inlet steam superheater pipeline, the discharge end of the steam superheater is connected to the medium-pressure waste boiler, the discharge end of the medium-pressure waste boiler is connected to the boiler water heater, the discharge end of the boiler water heater is connected to the low-pressure waste boiler, and the discharge end of the low-pressure waste boiler is connected to the heat exchanger.

[0011] In an optional solution: the gas compression module includes a compressor low-pressure cylinder, a compressor medium-pressure cylinder and a compressor high-pressure cylinder for compressing gas in sequence, and the compressor low-pressure cylinder, the compressor medium-pressure cylinder and the compressor high-pressure cylinder are connected to a compressor turbine for driving the operation thereof.

[0012] In an optional solution: the second discharge end of the cold exchanger is connected to the return end of the high-pressure cylinder of the compressor through a synthesis gas inlet compressor pipeline, and a synthesis gas inlet compressor valve is provided on the synthesis gas inlet compressor pipeline.

[0013] In an optional solution: the discharge end of the ammonia separator is also provided with a synthesis gas inlet cold exchange pipeline connected to the feed end of the cold exchanger.

[0014] In an optional scheme: the lithium bromide unit includes a lithium bromide unit, the second output end of the low-temperature water cooler is connected to the lithium bromide unit through a reheating cold water pipeline, and the reheating cold water pipeline is provided with a reheating cold water inlet valve of the lithium bromide unit, the second feed end of the low-temperature water cooler is connected to the lithium bromide unit through a cold water pipeline, and the cold water pipeline is provided with a cold water pump inlet valve, a cold water pump and a cold water pump outlet valve, the cold water pump is arranged between the cold water pump inlet valve and the cold water pump outlet valve, the water inlet end of the lithium bromide unit is provided with a lithium bromide unit cooling water inlet valve, the lithium bromide unit is provided with a lithium bromide unit steam regulating valve for adjusting air pressure, and the lithium bromide A lithium bromide unit cooling water outlet valve is provided at the water outlet end of the unit, a condensate return valve is provided at the condensate outlet of the lithium bromide unit, the hot water outlet on the lithium bromide unit is connected to the water inlet end of the low-pressure waste boiler through a hot water recovery pipeline, a boiler water return valve is provided on the hot water recovery pipeline, a boiler water inlet lithium bromide unit pipeline is provided at the raw material inlet of the lithium bromide unit, a boiler water circulation pump outlet valve is provided on the boiler water inlet lithium bromide unit pipeline, the boiler water circulation pump outlet valve is connected to the boiler water circulation pump, the other end of the boiler water circulation pump is connected to the discharge end of the low-pressure waste boiler, and a boiler water circulation pump inlet valve is provided between the low-pressure waste boiler and the boiler water circulation pump.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The hydrogen and nitrogen separated in the present application are recovered through the synthesis gas cold exchange pipeline and the cold exchanger for cold recovery. The recovered hydrogen and nitrogen enter the high-pressure cylinder of the compressor through the synthesis gas compressor valve and the synthesis gas compressor pipeline, and are mixed and pressurized with the hydrogen and nitrogen sent from the intermediate-pressure cylinder of the compressor to complete the recycling, save resources, reduce the turbine load in the ammonia synthesis production process, and achieve energy-saving effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the present invention.

[0018] Notes on the reference numerals: 1. LiBr unit cooling water inlet valve; 2. LiBr unit steam regulating valve; 3. Boiler water inlet pipeline to LiBr unit; 4. Synthesis gas inlet pipeline to steam superheater; 5. Hydrogen and nitrogen inlet pipeline to ammonia synthesis tower; 6 ammonia synthesis tower; 7. Steam superheater; 8. Boiler water circulation pump outlet valve; 9. LiBr unit cooling water outlet valve; 10. LiBr unit; 11. Reheating cold water inlet valve to LiBr unit; 12. Cold water pump; 13. Cold water Pump inlet valve; 14. Cold water pump outlet valve; 15. Cold water pipeline; 16. Hot water recovery pipeline; 17. Boiler water return valve; 18. Condensate return valve; 19. Boiler water circulation pump; 20. Boiler water circulation pump inlet valve; 21. Low-pressure waste boiler; 22. Medium-pressure waste boiler; 23. Boiler water heater; 24. Heat exchanger; 25. Water cooler; 26. Low-temperature water cooler; 27. Cold exchanger; 28. Reheating cold water pipeline; 29. ​​Ammonia synthesis supplement gas pipeline; 30. ammonia synthesis supplementary gas valve; 31. compressor low pressure cylinder; 32. compressor outlet valve; 33. hydrogen and nitrogen pipeline; 34. compressor medium pressure cylinder; 35. compressor high pressure cylinder; 36. compressor steam turbine; 37. synthesis gas inlet compressor pipeline; 38. synthesis gas inlet compressor valve; 39. primary ammonia cooler ammonia inlet valve; 40. primary ammonia cooler; 41. synthesis gas inlet cold exchange pipeline; 42. medium pressure gas ammonia pipeline; 43. secondary ammonia cooler; 4 4. Ammonia inlet valve for secondary ammonia cooler; 45. Ammonia separator; 46. Ammonia discharge valve; 47. Ammonia pipeline for ammonia cooler; 48. Liquid ammonia delivery valve; 49. Ammonia ice machine water cooler; 50. Ice machine system ammonia delivery valve; 51. Liquid ammonia storage tank; 52. Ammonia gas pipeline; 53. Ice machine steam turbine; 54. Medium-pressure ammonia gas valve; 55. Low-pressure ammonia gas valve; 56. Low-pressure ammonia gas pipeline; 57. Ice machine low-pressure cylinder; 58. Ice machine high-pressure cylinder; 59. Ice machine ammonia gas delivery valve. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] like Figure 1 As shown, an embodiment of the present invention provides a processing system for reducing steam consumption in an ammonia synthesis production process, comprising an ammonia synthesis supplementary gas pipeline 29 for conveying hydrogen and nitrogen, an ammonia synthesis supplementary gas valve 30 being provided on the ammonia synthesis supplementary gas pipeline 29, a lower end of the ammonia synthesis supplementary gas pipeline 29 being connected to a gas compression module for compressing gas, an output end of the gas compression module being communicated with a heat exchange module through a hydrogen and nitrogen pipeline 33, a compressor outlet valve 32 being provided on the hydrogen and nitrogen pipeline 33, a first output end of the heat exchange module being communicated with a feed end of an ammonia synthesis tower 6 through a hydrogen and nitrogen inlet ammonia synthesis tower pipeline 5, a second output end of the heat exchange module being communicated with a cooling module, the cooling module and the heat exchange module being interacted with a lithium bromide unit, a discharge end of the cooling module being communicated with a feed end of a liquid ammonia storage tank 51, and an ammonia release valve 46 being provided on the pipeline between the liquid ammonia storage tank 51 and an ammonia separator 45;

[0021] The cooling module includes a water cooler 25, the discharge end of the water cooler 25 is communicated with a low-temperature water cooler 26, the discharge end of the low-temperature water cooler 26 is communicated with a cold exchanger 27, the discharge end of the cold exchanger 27 is communicated with a primary ammonia cooler 40, the discharge end of the primary ammonia cooler 40 is communicated with a secondary ammonia cooler 43, the discharge end of the secondary ammonia cooler 43 is communicated with an ammonia separator 45, the second discharge end of the secondary ammonia cooler 43 of the primary ammonia cooler 40 is communicated with a liquid ammonia storage tank 51 through an ammonia pipeline 47 for an ammonia cooler, the second discharge end of the primary ammonia cooler 40 is provided with a primary ammonia cooler ammonia inlet valve 39, the second discharge end of the secondary ammonia cooler 43 is provided with a secondary ammonia cooler ammonia inlet valve 44, and the ammonia pipeline 47 for an ammonia cooler is provided with a liquid ammonia delivery valve 48;

[0022] The exhaust end of the first-stage ammonia cooler 40 is connected to the low-pressure cylinder 57 of the ice machine through a low-pressure ammonia pipeline 56, and a low-pressure ammonia valve is provided on the low-pressure ammonia pipeline 56. The exhaust end of the second-stage ammonia cooler 43 is connected to the high-pressure cylinder 58 of the ice machine through a medium-pressure ammonia pipeline 42, and a medium-pressure ammonia valve 54 is provided on the medium-pressure ammonia pipeline 42. The high-pressure cylinder 58 of the ice machine and the low-pressure cylinder 57 of the ice machine are connected to the ice machine steam turbine 53 for driving the ice machine to work. The discharge end of the low-pressure cylinder 57 is connected to the feed end of the ice machine high-pressure cylinder 58 through a pipeline, and the discharge end of the ice machine high-pressure cylinder 58 is connected to the ammonia ice machine water cooler 49 through the gas ammonia pipeline 52. The gas ammonia pipeline 52 is provided with an ice machine gas ammonia delivery valve 59. The discharge end of the ammonia ice machine water cooler 49 is connected to the feed end of the liquid ammonia storage tank 51. The pipeline between the ammonia ice machine water cooler 49 and the liquid ammonia storage tank 51 is provided with an ice machine system ammonia delivery valve 50;

[0023] The heat exchange module includes a heat exchanger 24 connected to the hydrogen-nitrogen pipeline 33 and a steam superheater 7 connected to the discharge end of the steam superheater 7. The steam superheater 7 is connected to the ammonia synthesis tower 6 through the synthesis gas inlet steam superheater pipeline 4. The discharge end of the steam superheater 7 is connected to the medium-pressure waste boiler 22. The discharge end of the medium-pressure waste boiler 22 is connected to the boiler water heater 23. The discharge end of the boiler water heater 23 is connected to the low-pressure waste boiler 21. The discharge end of the low-pressure waste boiler 21 is connected to the heat exchanger 24;

[0024] The gas compression module comprises a compressor low-pressure cylinder 31, a compressor medium-pressure cylinder 34 and a compressor high-pressure cylinder 35 for compressing gas in sequence, and the compressor low-pressure cylinder 31, the compressor medium-pressure cylinder 34 and the compressor high-pressure cylinder 35 are connected to a compressor turbine 36 for driving the operation thereof;

[0025] The second discharge end of the cold exchanger 27 is connected to the return end of the compressor high-pressure cylinder 35 through a synthesis gas inlet compressor pipeline 37, and a synthesis gas inlet compressor valve 38 is provided on the synthesis gas inlet compressor pipeline 37;

[0026] The discharge end of the ammonia separator 45 is also provided with a synthesis gas cold exchange pipeline 41 connected to the feed end of the cold exchanger 27;

[0027] The lithium bromide unit includes a lithium bromide unit 10, the second output end of the low-temperature water cooler 26 is connected to the lithium bromide unit 10 through a reheating cold water pipeline 28, and the reheating cold water pipeline 28 is provided with a reheating cold water inlet valve 11 for lithium bromide unit, the second feed end of the low-temperature water cooler 26 is connected to the lithium bromide unit 10 through a cold water pipeline 15, and the cold water pipeline 15 is provided with a cold water pump inlet valve 13, a cold water pump 12 and a cold water pump outlet valve 14, and the cold water pump 12 is arranged between the cold water pump inlet valve 13 and the cold water pump outlet valve 14, the water inlet end of the lithium bromide unit 10 is provided with a lithium bromide unit cooling water inlet valve 1, the lithium bromide unit 10 is provided with a lithium bromide unit steam regulating valve 2 for adjusting air pressure, and the lithium bromide unit 1 0 is provided with a lithium bromide unit cooling water outlet valve 9, the condensed water outlet on the lithium bromide unit 10 is provided with a condensate return valve 18, the hot water outlet on the lithium bromide unit 10 is connected to the water inlet end of the low-pressure waste boiler 21 through a hot water recovery pipeline 16, and a boiler water return valve 17 is provided on the hot water recovery pipeline 16. The raw material inlet of the lithium bromide unit 10 is provided with a boiler water inlet lithium bromide unit pipeline 3, and the boiler water inlet lithium bromide unit pipeline 3 is provided with a boiler water circulation pump outlet valve 8, the boiler water circulation pump outlet valve 8 is connected with a boiler water circulation pump 19, and the other end of the boiler water circulation pump 19 is connected with the discharge end of the low-pressure waste boiler 21, and a boiler water circulation pump inlet valve 20 is provided between the low-pressure waste boiler 21 and the boiler water circulation pump 19:

[0028] Lithium bromide unit selection:

[0029] 1. Unit selection: H2 steam hot water two-stage lithium bromide absorption chiller

[0030] 2. Cold water index: inlet 15℃, outlet 6℃, flow rate 1000m3 / h;

[0031] 3. Hot water index: inlet 125℃, outlet 80℃, flow rate 130m3 / h;

[0032] 4. Steam index: 0.3MPa steam 5t / h;

[0033] 5. Cooling water: inlet 28℃, outlet 42℃, flow rate 1800m3 / h;

[0034] Hot water circulation pump equipment selection:

[0035] 1. Centrifugal pump; rated flow, m3 / h: 150; head, m: 50.

[0036] 2. Working medium: boiler water; temperature, ℃: 175.

[0037] Low temperature water cooler equipment selection:

[0038] 1.Φ1600L=6000mm n=1500F=800m2

[0039] 2. Design pressure: Shell side: 1.0MPa(G) Tube side: 16.5MPa(G)

[0040] 3. Design temperature: Shell side: 40℃ Tube side: 50℃;

[0041] The hydrogen and nitrogen gas sent from the upper process enters the compressor low-pressure cylinder 31 through the ammonia synthesis supplementary gas pipeline 29 and the ammonia synthesis supplementary gas valve 30;

[0042] The gas is pressurized to 14.5 MPa through the compressor low-pressure cylinder 31, the compressor medium-pressure cylinder 34, and the compressor high-pressure cylinder 35, and enters the heat exchanger 24 through the compressor outlet valve 32 and the hydrogen-nitrogen pipeline 33 to complete the gas heat exchange;

[0043] The hydrogen and nitrogen gases heat exchanged in the heat exchanger 24 enter the ammonia synthesis tower 6 through the hydrogen and nitrogen gas inlet ammonia synthesis tower pipeline 5 for reaction;

[0044] The synthesis gas after the reaction is passed through the synthesis gas steam superheater pipeline 4, the steam superheater 7, the medium pressure waste boiler 22, the boiler water heater 23, the low pressure waste boiler 21, and the heat exchanger 24 for heat recovery;

[0045] The synthesis gas after heat recovery is cooled to -12°C by the water cooler 25, the low-temperature water cooler 26, the cold exchanger 27, the primary ammonia cooler 40, and the secondary ammonia cooler 43, and then enters the ammonia separator 45 for gas-liquid separation;

[0046] The separated hydrogen and nitrogen are recovered through the synthesis gas cold exchange pipeline 41 and the cold exchanger 27. The recovered hydrogen and nitrogen enter the compressor high-pressure cylinder 35 through the synthesis gas compressor valve 38 and the synthesis gas compressor pipeline 37, and are mixed and pressurized with the hydrogen and nitrogen sent from the compressor medium-pressure cylinder 34 to complete the recycling.

[0047] The liquid nitrogen separated by the ammonia separator 45 is sent to the liquid ammonia storage tank 51 through the ammonia release valve 46 for use in cooling the primary ammonia cooler 40 and the secondary ammonia cooler 43 .

[0048] The ammonia gas evaporated from the primary ammonia cooler 40 enters the low-pressure cylinder 57 of the ice machine through the low-pressure gas ammonia pipeline 56 and the low-pressure gas ammonia valve 55; the ammonia gas evaporated from the secondary ammonia cooler 43 enters the high-pressure cylinder 58 of the ice machine through the medium-pressure gas ammonia pipeline 42 and the medium-pressure gas ammonia valve 54; after being pressurized, it passes through the ice machine 1.6MPa gas ammonia external valve 59, the ammonia ice machine water cooler 49, and the ice machine system ammonia delivery valve 50, and is delivered to the liquid ammonia storage tank 51.

[0049] The low-temperature heat exchanger is put into operation, the cold water pump inlet valve 13 and the reheating cold water inlet valve 11 of the lithium bromide unit are opened, the low-temperature water cooler 26 and the reheating cold water pipeline 28 are filled with water, and the cold water pump 12 is exhausted; after the cold water pump 12 is exhausted, the cold water pump 12 is started, and the cold water pump outlet valve 14 is slowly opened to establish the cold water circulation of the lithium bromide unit 10; the cooling water outlet valve 9 of the lithium bromide unit and the cooling water inlet valve 1 of the lithium bromide unit are opened, and the cooling water outlet valve 14 of the lithium bromide unit is controlled by the cooling water inlet valve 1 of the lithium bromide unit. The water temperature is controlled at above 25°C; start the lithium bromide unit 10, and after the quenching water pump of the lithium bromide unit 10 operates normally, open the boiler water circulation pump inlet valve 20 and the boiler water return valve 17 to fill the hot water recovery pipeline 16, the boiler water inlet pipeline 3 of the lithium bromide unit, and the lithium bromide unit 10, and exhaust the boiler water circulation pump 19; after the boiler water circulation pump 19 is exhausted, start the boiler water circulation pump 19, slowly open the boiler water circulation pump outlet valve 8, and establish the hot water circulation of the lithium bromide unit 10. Adjust the load of the lithium bromide unit 10 according to the outlet synthesis gas temperature of the low-temperature water cooler 26; in normal production, the outlet synthesis gas temperature of the low-temperature water cooler 26 is controlled below 25°C in summer and below 20°C in winter. After the outlet synthesis gas temperature of the low-temperature water cooler 26 is reduced, the liquid ammonia consumption of the first-level ammonia cooler 40 and the second-level ammonia cooler 43 is reduced from 15t / h to 7t / h.

[0050] Operation Notes

[0051] 1. After the ammonia synthesis unit is shut down in an emergency, the boiler water circulation pump 19 stops running, and the boiler water circulation pump outlet valve 8 and the boiler water return valve 17 are closed; the lithium bromide unit 10 operates normally, and the cooling water outlet temperature is 25℃-30℃ through the opening adjustment of the lithium bromide unit cooling water inlet valve 1.

[0052] 2. After the ammonia synthesis unit is shut down for a short time, the boiler water circulation pump 19 stops running, and the boiler water circulation pump outlet valve 8 and the boiler water return valve 17 are closed; the lithium bromide unit 10 operates normally, and the cooling water outlet temperature is 25℃-30℃ through the opening adjustment of the lithium bromide unit cooling water inlet valve 1.

[0053] 3. After the ammonia synthesis unit is shut down for a long time, the boiler water circulation pump 19 stops running, and the boiler water circulation pump outlet valve 8 and the boiler water return valve 17 are closed; the cooling water outlet temperature is controlled at 25°C-30°C by adjusting the opening of the cooling water inlet valve 1. After the lithium bromide unit 10 runs for 30 minutes, the lithium bromide unit 10 is stopped; the cooling water inlet valve 1, the cold water pump outlet valve 14, and the reheated cold water inlet valve 11 of the lithium bromide unit are closed, and the cold water pump 12 is stopped. The lithium bromide unit 10 is started to run in self-dilution mode.

[0054] 4. Poor vacuum; Reasons: 1) Leakage of the unit; 2) Poor performance of the vacuum pump or failure of the exhaust system;

[0055] Treatment measures: 1) Check for leaks and eliminate them; 2) Measure the performance of the vacuum pump and troubleshoot the exhaust system.

[0056] 5. Crystallization elimination during downtime

[0057] Crystallization during shutdown is caused by insufficient dilution of the solution during shutdown or low ambient temperature. Once crystallization occurs, the solution pump cannot operate. Heat the solution pump housing and inlet and outlet with steam or hot water until the pump can operate. When heating, be careful not to allow steam and condensed water to enter the motor and control equipment. Never heat electrical equipment directly.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A system for reducing steam consumption in an ammonia synthesis production process, characterized in that: The invention comprises an ammonia synthesis supplementary gas pipeline (29) for conveying hydrogen and nitrogen. The ammonia synthesis supplementary gas pipeline (29) is provided with an ammonia synthesis supplementary gas valve (30). The lower end of the ammonia synthesis supplementary gas pipeline (29) is connected to a gas compression module for compressing gas. The output end of the gas compression module is communicated with a heat exchange module through a hydrogen and nitrogen pipeline (33). The hydrogen and nitrogen pipeline (33) is provided with a compressor outlet valve (32). The first output end of the heat exchange module is communicated with the feed end of the ammonia synthesis tower (6) through a hydrogen and nitrogen inlet ammonia synthesis tower pipeline (5). The second output end of the heat exchange module is communicated with a cooling module. The cooling module and the heat exchange module interact with a lithium bromide unit. The discharge end of the cooling module is communicated with the feed end of a liquid ammonia storage tank (51). An ammonia discharge valve (46) is provided on the pipeline between the liquid ammonia storage tank (51) and an ammonia separator (45).

2. The system for reducing steam consumption in ammonia synthesis production process according to claim 1, characterized in that: The cooling module comprises a water cooler (25), the discharge end of the water cooler (25) is connected to a low-temperature water cooler (26), the discharge end of the low-temperature water cooler (26) is connected to a cold exchanger (27), the discharge end of the cold exchanger (27) is connected to a primary ammonia cooler (40), the discharge end of the primary ammonia cooler (40) is connected to a secondary ammonia cooler (43), the discharge end of the secondary ammonia cooler (43) is connected to an ammonia separator (45). The first ammonia cooler (40) and the second second ammonia cooler (43) are connected, the second discharge end of the first ammonia cooler (40) and the second second ammonia cooler (43) are connected to the liquid ammonia storage tank (51) through an ammonia pipeline (47) for the ammonia cooler, the second discharge end of the first ammonia cooler (40) is provided with a first ammonia cooler ammonia inlet valve (39), the second discharge end of the second ammonia cooler (43) is provided with a second ammonia cooler ammonia inlet valve (44), and the ammonia pipeline (47) for the ammonia cooler is provided with a liquid ammonia outlet valve (48).

3. The system for reducing steam consumption in ammonia synthesis production process according to claim 2, characterized in that: The exhaust end of the primary ammonia cooler (40) is connected to the low-pressure cylinder (57) of the ice machine through a low-pressure ammonia pipeline (56), and a low-pressure ammonia valve is provided on the low-pressure ammonia pipeline (56). The exhaust end of the secondary ammonia cooler (43) is connected to the high-pressure cylinder (58) of the ice machine through a medium-pressure ammonia pipeline (42), and a medium-pressure ammonia valve (54) is provided on the medium-pressure ammonia pipeline (42). The high-pressure cylinder (58) and the low-pressure cylinder (57) of the ice machine are connected to the ice machine steam turbine (53) for driving the ice machine to work. The discharge end of the low-pressure cylinder (57) is connected to the feed end of the ice machine high-pressure cylinder (58) through a pipeline, and the discharge end of the ice machine high-pressure cylinder (58) is connected to the ammonia ice machine water cooler (49) through a gas ammonia pipeline (52). The gas ammonia pipeline (52) is provided with a gas ammonia delivery valve (59) for the ice machine. The discharge end of the ammonia ice machine water cooler (49) is connected to the feed end of the liquid ammonia storage tank (51), and the pipeline between the ammonia ice machine water cooler (49) and the liquid ammonia storage tank (51) is provided with an ice machine system ammonia delivery valve (50).

4. The system for reducing steam consumption in ammonia synthesis production process according to claim 3, characterized in that: The heat exchange module comprises a heat exchanger (24) connected to a hydrogen-nitrogen pipeline (33) and a steam superheater (7) connected to a discharge end of a steam superheater (7); the steam superheater (7) is connected to an ammonia synthesis tower (6) via a synthesis gas inlet steam superheater pipeline (4); the discharge end of the steam superheater (7) is connected to a medium-pressure waste boiler (22); the discharge end of the medium-pressure waste boiler (22) is connected to a boiler water heater (23); the discharge end of the boiler water heater (23) is connected to a low-pressure waste boiler (21); and the discharge end of the low-pressure waste boiler (21) is connected to the heat exchanger (24).

5. The system for reducing steam consumption in ammonia synthesis production process according to claim 4, characterized in that: The gas compression module comprises a compressor low-pressure cylinder (31), a compressor medium-pressure cylinder (34) and a compressor high-pressure cylinder (35) for sequentially compressing gas, wherein the compressor low-pressure cylinder (31), the compressor medium-pressure cylinder (34) and the compressor high-pressure cylinder (35) are connected to a compressor turbine (36) for driving the operation thereof.

6. The system for reducing steam consumption in ammonia synthesis production process according to claim 5, characterized in that: The second discharge end of the cold exchanger (27) is connected to the return end of the compressor high-pressure cylinder (35) through a synthesis gas inlet compressor pipeline (37), and a synthesis gas inlet compressor valve (38) is provided on the synthesis gas inlet compressor pipeline (37).

7. The system for reducing steam consumption in ammonia synthesis production process according to claim 6, characterized in that: The discharge end of the ammonia separator (45) is also provided with a synthesis gas cold exchange pipeline (41) which is connected to the feed end of the cold exchanger (27).

8. The system for reducing steam consumption in ammonia synthesis production process according to claim 7, characterized in that: The lithium bromide unit comprises a lithium bromide unit (10), a second output end of the low-temperature water cooler (26) is connected to the lithium bromide unit (10) via a reheating cold water pipeline (28), a reheating cold water inlet valve (11) is provided on the reheating cold water pipeline (28), a second feed end of the low-temperature water cooler (26) is connected to the lithium bromide unit (10) via a cold water pipeline (15), and a cold water pipeline (15) is provided on the cold water pipeline (15). There are a cold water pump inlet valve (13), a cold water pump (12) and a cold water pump outlet valve (14), wherein the cold water pump (12) is arranged between the cold water pump inlet valve (13) and the cold water pump outlet valve (14), a lithium bromide unit cooling water inlet valve (1) is arranged at the water inlet end of the lithium bromide unit (10), a lithium bromide unit steam regulating valve (2) for regulating air pressure is arranged on the lithium bromide unit (10), and the lithium bromide unit ( A cooling water outlet valve (9) of a lithium bromide unit is provided at the water outlet end of the lithium bromide unit (10); a condensate return valve (18) is provided at the condensate outlet of the lithium bromide unit (10); a hot water outlet of the lithium bromide unit (10) is connected to the water inlet end of a low-pressure waste boiler (21) through a hot water recovery pipeline (16); a boiler water return valve (17) is provided on the hot water recovery pipeline (16); a boiler water inlet pipeline (3) of the lithium bromide unit (10) is provided at the raw material inlet of the lithium bromide unit (10); a boiler water circulation pump outlet valve (8) is provided on the boiler water inlet pipeline (3); the boiler water circulation pump outlet valve (8) is connected to a boiler water circulation pump (19); the other end of the boiler water circulation pump (19) is connected to the discharge end of the low-pressure waste boiler (21); a boiler water circulation pump inlet valve (20) is provided between the low-pressure waste boiler (21) and the boiler water circulation pump (19).