Comprehensive utilization device and comprehensive utilization method for acid gas of ammonia synthesis device

Abstract

The invention belongs to a comprehensive utilization device and a comprehensive utilization method for acid gas of a synthetic ammonia device. Comprising a gasification system acid gas unit, a low-temperature methanol washing system acid gas unit and a conversion stripping tower acid gas unit, wherein the gasification system acid gas unit is respectively connected with a heat tracing gas inlet of a Claus combustion furnace and a heat tracing gas inlet of a waste gas combustion furnace in a sulfur preparation unit; an acid gas unit of the low-temperature methanol washing system is connected with an inlet of the Claus combustion furnace, and an acid gas unit of the conversion stripping tower is connected with an inlet of the waste gas combustion furnace; a top tail gas outlet of the waste gas combustion furnace is connected with a tail gas treatment unit, the tail gas treatment unit is coupled with an ammonium sulfite solution preparation unit, and the ammonium sulfite solution preparation unit is connected with an ammonium sulfate preparation unit; the system has the advantages that the acid gas in the ammonia synthesis device is comprehensively treated, the circulating operation of the whole system is realized, the environment-friendly emission problem of an enterprise is solved, and meanwhile, relatively large profits are brought to the enterprise.

Description

Technical Field

[0001] The invention belongs to the technical field of acid gas treatment, and in particular relates to a comprehensive utilization device and a comprehensive utilization method of acid gas in a synthetic ammonia device. Background Art

[0002] In the prior art, the acid gas produced by the high-temperature hot water tower in the gasification system is condensed and directly discharged into the flare for combustion. The above-mentioned gas is a production gas. Although the direct emission of harmful substances can be reduced through flare combustion, it cannot completely eliminate the environmental pollution problem. Secondary pollutants such as sulfur dioxide and nitrogen oxides may be generated during the combustion process. These substances have potential hazards to the environment and human health. Furthermore, the production gas may contain flammable and explosive components, and there are safety hazards if it is directly discharged into the flare for combustion. If the gas mixing ratio is not appropriate, it may cause an explosion accident. Furthermore, based on environmental protection requirements and the company's own cognition, how to treat the gas has become a technical problem that needs to be solved urgently. At the same time, the acid gas components in the synthetic ammonia unit are different. The conventional operation is to treat each of them separately. This method has the defects of high investment and operating costs, which has become an obstacle to the development of this type of enterprise. How to achieve comprehensive treatment of the aforementioned acid gas and improve the economic benefits of the enterprise has become a problem that needs to be solved urgently. Summary of the invention

[0003] The present invention provides a device and method for comprehensively utilizing acid gas from a synthetic ammonia device, which are used to solve the technical problems raised in the above-mentioned background technology.

[0004] The technical solution of the present invention is:

[0005] A synthetic ammonia unit acid gas comprehensive utilization device comprises a gasification system acid gas unit, a low temperature methanol washing system acid gas unit and a shift stripping tower acid gas unit, wherein the gasification system acid gas unit is respectively connected to the tracing gas inlet of the Claus combustion furnace and the tracing gas inlet of the waste gas combustion furnace in the sulfur preparation unit; the low temperature methanol washing system acid gas unit is connected to the inlet of the Claus combustion furnace, and the shift stripping tower acid gas unit is connected to the inlet of the waste gas combustion furnace; the top tail gas outlet of the waste gas combustion furnace is connected to the tail gas treatment unit, the tail gas treatment unit is coupled to the ammonium sulfite solution preparation unit, and the ammonium sulfite solution preparation unit is connected to the ammonium sulfate preparation unit.

[0006] The beneficial effects of the present invention are as follows: the present invention provides a system capable of comprehensively treating acid gas in a synthetic ammonia device, which can specifically treat acid gas in a gasification system acid gas unit, a low-temperature methanol washing system acid gas unit and a conversion stripping tower acid gas unit. Through research, it is known that the CO content (molar concentration) in the acid gas in the gasification system acid gas unit is 31.6%, the H2 content (molar concentration) is 19.3%, and the carbon dioxide content (molar concentration) is 46%. Among them, the CO and H2 contents are relatively high, and the calorific value is relatively high. The system can be used as fuel gas for an incinerator and a Claus burner to achieve the purpose of saving natural gas and other fuels and saving operating costs, while achieving stable operation of the incinerator and the Claus burner; the exhaust gas after combustion is treated by the exhaust gas treatment unit, which can not only achieve the characteristics of meeting emission standards and being environmentally friendly, but also can use the absorption liquid of the treated exhaust gas to prepare ammonium sulfate, prepare for the preparation of a new multi-element fertilizer, and achieve the cyclic operation of the entire system, which not only solves the environmental emission problem of the enterprise, but also brings greater profits to the enterprise.

[0007] Preferably, the tail gas treatment unit includes an ammonia water absorption tower connected to the tail gas outlet of the exhaust gas combustion furnace, the gas phase outlet at the top of the ammonia water absorption tower is connected to the inlet of the water washing tower, and the gas phase outlet at the top of the water washing tower is connected to the atmosphere; the ammonium sulfite solution preparation unit includes a desalted water storage tank, the desalted water storage tank is connected to the water washing tower through a desalted water replenishment pump and an eighth regulating valve, the bottom outlet of the water washing tower is connected to the circulation port at the top of the water washing tower through the bottom pump of the water washing tower, a fifth tee is provided between the bottom pump of the water washing tower and the circulation port at the top of the water washing tower, and the third end of the fifth tee is connected to the liquid inlet of the ammonia water absorption tower through the seventh regulating valve; the bottom outlet of the ammonia water absorption tower is connected to the circulation port at the top of the ammonia water absorption tower through the bottom pump of the ammonia water absorption tower, a fourth tee is provided between the bottom pump of the ammonia water absorption tower and the circulation port at the top of the ammonia water absorption tower, and the third end of the fourth tee is connected to the ammonium sulfate concentration oxidation tower through the sixth regulating valve.

[0008] Preferably, the ammonia absorption tower is provided with an ammonia absorption tower replenishing port, and the ammonia absorption tower replenishing port is connected to an ammonia tank with an ammonia pipeline through an ammonia pump.

[0009] Preferably, the ammonium sulfate preparation unit comprises an ammonium sulfate concentrating oxidation tower, which is respectively connected to the dirty nitrogen gas exhaust pipe and the hot air pipe in the air separation system, the bottom outlet of the ammonium sulfate concentrating oxidation tower is connected to the crystallizer, the solid phase outlet of the crystallizer is connected to the compound fertilizer production unit, and the liquid phase outlet of the crystallizer is connected to the liquid replenishment port of the ammonia water tank; the top gas phase outlet of the ammonium sulfate concentrating oxidation tower is connected to the inlet of the water washing tower.

[0010] Preferably, the compound fertilizer production unit includes a compound fertilizer granulation tower, a urea solution storage tank, and a potassium chloride warehouse; the compound fertilizer granulation tower includes a granulation nozzle arranged in the middle and upper part of the compound fertilizer granulation tower, the inlet of the granulation nozzle is connected to the outlets of the potassium chloride dissolving tank and the ammonium sulfate dissolving tank through a fourth regulating valve and a fifth regulating valve, respectively, the solid phase inlet of the potassium chloride dissolving tank is connected to the potassium chloride warehouse through a first elevator and a first weighing scale, and the solid phase inlet of the ammonium sulfate dissolving tank is connected to the solid phase outlet of the crystallizer through a second elevator and a second weighing scale; the liquid phase outlets of the potassium chloride dissolving tank and the ammonium sulfate dissolving tank are connected to the first tee through their respective corresponding first regulating valves and second regulating valves, respectively, and the third end of the first tee is connected to the outlet of the urea solution storage tank through a urea solution pump; the setting height of the potassium chloride dissolving tank is greater than the setting height of the ammonium sulfate dissolving tank, and the outlet of the potassium chloride dissolving tank is connected to the inlet of the ammonium sulfate dissolving tank through a third regulating valve.

[0011] Preferably, the gasification system acid gas unit comprises a gasification high-temperature flash tank, a gas phase outlet at the top of the gasification high-temperature flash tank is connected to a gas phase inlet at the bottom of a gasification high-temperature hot water tower, a gasification low-temperature ash water pipeline is provided at the upper part of the gasification high-temperature hot water tower, a gas phase outlet at the top of the gasification high-temperature hot water tower is connected to a first acid gas cooler, a liquid phase outlet of the first acid gas cooler is connected to a gasification clarification tank, and a gas phase outlet of the first acid gas cooler is respectively connected to a heating gas inlet of a Claus burner and a heating gas inlet of a waste gas burner through a third tee.

[0012] Preferably, a second tee and a tenth regulating valve are provided in sequence between the gas phase outlet of the first acid gas cooler and the third tee, and the third end of the second tee is connected to the conversion furnace in the conversion system through a ninth regulating valve and a fuel gas compressor in sequence; an eleventh regulating valve is provided between the third tee and the heat gas inlet of the Claus burner.

[0013] Preferably, the acid gas unit of the low-temperature methanol washing system includes a methanol washing heat regenerator, the gas phase outlet of the methanol washing heat regenerator is connected to the acid gas liquid separator tank through a second acid gas cooler, and the gas phase outlet of the acid gas liquid separator tank is connected to the raw gas inlet of the Claus combustion furnace; the conversion stripping tower acid gas unit includes a low-pressure flash tank, the gas phase outlet of the low-pressure flash tank is connected to the gas phase inlet of the lower part of the conversion stripping tower, the upper inlet of the conversion stripping tower is connected to the waste liquid pipeline of the conversion ammonia washing tower, and the gas phase outlet at the top of the conversion stripping tower is connected to the inlet of the waste gas combustion furnace.

[0014] Preferably, the sulfur preparation unit comprises a Claus combustion furnace, the outlet of the Claus combustion furnace is connected to the inlet of the Claus reactor, the liquid phase outlet of the Claus reactor is connected to the sulfur warehouse through a sulfur granulation device, and the gas phase outlet of the Claus reactor is connected to the inlet of the exhaust gas combustion furnace.

[0015] The present invention also provides a method for comprehensive utilization of acid gas from a synthetic ammonia device, the method comprising the following steps:

[0016] Step 1: The high-temperature black water in the gasification system enters the gasification high-temperature flash tank for flash evaporation. The gas phase after flash evaporation enters the gasification high-temperature hot water tower to transfer mass and heat with the gasification low-temperature ash water from the gasification low-temperature ash water pipeline. The non-condensable gas and part of the water vapor that are not absorbed enter the first acid gas cooler for condensation. The condensed liquid phase enters the gasification clarification tank for repeated use as gasification circulating water. The uncondensed acid gas enters the second tee. One path is sent to the fuel gas compressor through the ninth regulating valve for pressurization. After the pressure is increased to 6.3 MPa (G), it is sent to the conversion furnace in the conversion system as a raw material for recycling. The other path enters the third tee through the first regulating valve and enters the exhaust gas combustion furnace and the Claus combustion furnace respectively for use as fuel gas.

[0017] Step 2: The low-pressure steam in the low-pressure flash tank of the gasification system enters the conversion stripping tower as the stripping heat source of the conversion stripping tower, and is countercurrently contacted with the conversion ammonia washing tower waste liquid from the conversion ammonia washing tower waste liquid pipeline, so as to strip out the acid gas in the conversion ammonia washing tower waste liquid, and the stripped acid gas enters the waste gas combustion furnace for incineration treatment;

[0018] Step 3: The acid gas from the methanol heat washing regenerator enters the second acid gas cooler for condensation, and the methanol and water in the acid gas are condensed out. The condensed acid gas enters the acid gas separator for separation, and the separated gas phase enters the Claus burner for combustion;

[0019] Step 4: The acid gas in the above steps 1 and 3 enters the Claus combustion furnace for combustion, partially converts the hydrogen sulfate into sulfur dioxide, and then enters the Claus reactor for hydrogen sulfide and sulfur dioxide to react to produce liquid sulfur, the liquid sulfur enters the sulfur granulation device for granulation, and the granulated sulfur enters the sulfur warehouse for packaging and sales;

[0020] The tail gas produced in the Claus reactor enters the waste gas combustion furnace for incineration treatment; the tail gas produced in the Claus reactor contains some carbon monoxide and sulfur dioxide that have not been fully reacted;

[0021] Step 5: The acid gas in the aforementioned step 1, the acid gas in step 2, and the tail gas produced in the Claus reactor in step 4 enter the exhaust gas combustion furnace together for full combustion, and the tail gas of the exhaust gas combustion furnace enters the ammonia absorption tower, and the sulfur dioxide in the tail gas is absorbed by ammonia in the ammonia absorption tower. The tail gas after ammonia absorption enters the water washing tower for washing and then meets the emission standards;

[0022] Step 6: The desalted water in the desalted water storage tank is pressurized by the desalted water replenishment pump and sent to the water washing tower to wash the tail gas after ammonia absorption, and the eighth regulating valve is used to adjust the amount of desalted water entering the water washing tower; the solution at the bottom of the water washing tower is pressurized by the water washing tower bottom pump and refluxed to the water washing tower through the circulation port at the top of the water washing tower, so as to control the mass concentration of ammonia in the solution within 5% under the premise of saving water, so as to facilitate the entry into the subsequent ammonia absorption tower under the premise of ensuring qualified tail gas emissions; when it is necessary to replenish desalted water, the desalted water replenishment pump and the eighth regulating valve can be opened;

[0023] Step 7: When the solution in step 6 reaches a predetermined threshold, the seventh regulating valve is opened to allow the solution in the fifth three-way valve to enter the ammonia absorption tower for use as an absorption liquid. The solution at the bottom of the ammonia absorption tower is pressurized by the bottom pump of the ammonia absorption tower and then refluxed from the circulation port at the top of the ammonia absorption tower to the ammonia absorption tower for recycling, so as to lay a foundation for entering the subsequent ammonium sulfate concentration oxidation tower on the premise of the absorption liquid. When the absorption liquid needs to be supplemented and the solution in step 6 does not reach the predetermined threshold, the ammonia pump is turned on to allow the ammonia tank with an ammonia pipeline to supplement ammonia as an absorption liquid into the ammonia absorption tower;

[0024] Step 8: When the solution in step 7 reaches a predetermined threshold, the sixth regulating valve is opened to allow the ammonium sulfite solution in the fourth three-way to enter the ammonium sulfate concentration oxidation tower for oxidation crystallization. The hot air in the hot air pipe takes away a portion of water vapor while oxidizing the ammonium sulfite, thereby concentrating the ammonium sulfate; the dirty nitrogen gas in the dirty nitrogen gas exhaust pipe enters the ammonium sulfate concentration oxidation tower to conduct secondary concentration of the ammonium sulfate; after the secondary concentration, the ammonium sulfate enters the crystallizer for crystallization, and the mother liquor after crystallization enters the ammonia water tank for use as the absorption liquid of the ammonia water absorption tower;

[0025] Step 9: The solid phase crystallized by the crystallizer in step 8 enters the ammonium sulfate dissolution tank inside the compound fertilizer granulation tower through the second weighing scale and the second elevator and can be used to prepare compound fertilizer;

[0026] Step 10: When sulfur-nitrogen binary compound fertilizer needs to be prepared, the first regulating valve, the fourth regulating valve and the third regulating valve are closed, and the second regulating valve and the fifth regulating valve are opened. The urea solution in the urea solution storage tank enters the ammonium sulfate dissolving tank through the urea solution pump, so that the urea solution with a concentration of 99% dissolves the ammonium sulfate, and after dissolution, the ammonium sulfate enters the granulation nozzle for granulation;

[0027] Step 11: When it is necessary to prepare sulfur-nitrogen-potassium ternary compound fertilizer, the first regulating valve, the second regulating valve, the third regulating valve and the fifth regulating valve are opened, and the fourth regulating valve is closed. The potassium chloride in the potassium chloride warehouse enters the potassium chloride dissolving tank through the first weighing scale and the first elevator, and the urea solution in the urea solution storage tank enters the potassium chloride dissolving tank and the ammonium sulfate dissolving tank respectively through the urea solution pump, so that the urea solution with a concentration of 99% dissolves the potassium chloride and the ammonium sulfate respectively. After the dissolution, the urea solution containing potassium chloride enters the ammonium sulfate dissolving tank by utilizing the height difference for mixing to obtain compound fertilizer slurry; the compound fertilizer slurry enters the granulation nozzle for granulation;

[0028] Step 12: When it is necessary to prepare nitrogen-potassium binary compound fertilizer, the solid phase crystallized by the crystallizer in step 8 is dried and then sold; the second regulating valve, the third regulating valve and the fifth regulating valve are closed, the first regulating valve and the fourth regulating valve are opened, and the urea solution in the urea solution storage tank enters the potassium chloride dissolving tank through the urea solution pump, so that the urea solution with a concentration of 99% dissolves the potassium chloride, and after dissolution, it enters the granulation nozzle for granulation.

[0029] A synthetic ammonia plant acid gas comprehensive utilization device and comprehensive utilization method are made according to the above scheme. The present invention provides a system capable of comprehensively treating acid gas in a synthetic ammonia plant, which can specifically treat acid gas in a gasification system acid gas unit, a low-temperature methanol washing system acid gas unit and a conversion stripping tower acid gas unit, and treat different acid gases according to their different components. The acid gas in the gasification system has a high content of CO and H2. On the one hand, it can be sent to the conversion furnace in the conversion system by setting a fuel gas compressor and used as a raw material for conversion reaction to achieve the purpose of saving energy consumption. On the other hand, it has a high calorific value and can be used as fuel gas for incinerators and Claus burners to achieve the purpose of saving natural gas and other fuels and saving operating costs, while achieving stable operation of the incinerator and Claus burner; for the acid gas in the low-temperature methanol washing system, it is used The Claus reactor is used to produce sulfur. The tail gas after sulfur production still contains a trace amount of sulfur dioxide. Direct discharge does not meet environmental protection requirements. Therefore, an incinerator is used to incinerate it with the conversion stripping acid gas and then send it to the tail gas treatment unit. The sulfur dioxide is absorbed to form ammonium sulfite, which is then oxidized to ammonium sulfate. After ammonium sulfate is crystallized and separated, it is used as a raw material for compound fertilizer production to produce multi-element fertilizer products, forming an acid gas closed-loop treatment, which ultimately brings profits to the enterprise while achieving environmental benefits. In summary, the device and process can bring good environmental and economic benefits to the enterprise; in addition, the tail gas treatment unit described in the present invention is coupled with the ammonium sulfite solution preparation unit, which can treat the tail gas and achieve standard discharge of the tail gas, and can also prepare ammonium sulfite solution in the process of step-by-step absorption, laying a foundation for the subsequent preparation of ammonium sulfate. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural schematic diagram of the present invention.

[0031] Numbers in the figure: 1. Gasification high-temperature flash tank; 2. Gasification low-temperature ash water pipeline; 3. Gasification high-temperature hot water tower; 4. Low-pressure flash tank; 5. First acid gas cooler; 6. Gasification clarification tank; 7. Shift stripping tower; 8. Shift ammonia washing tower waste liquid pipeline; 9. Methanol washing heat regenerator; 10. Second acid gas cooler; 11. Second three-way; 12. Ninth regulating valve; 13. Fuel gas compressor; 14. Shift furnace; 15. Tenth regulating valve; 16. Third three-way; 17. Eleventh regulating valve; 18. Claus combustion furnace; 19. Claus reactor; 20. Sulfur warehouse; 21. Waste gas combustion furnace; 22. Eighth regulating valve; 23. Desalted water feed pump; 24. Ammonia tank; 25. Water washing tower; 26. Fifth three-way; 27. Water washing tower bottom pump; 28. Seventh regulating valve; 2 9. Ammonia absorption tower; 30. Desalted water storage tank; 31. Sixth regulating valve; 32. Fourth three-way; 33. Ammonia absorption tower bottom pump; 34. Dirty nitrogen gas exhaust pipeline; 35. Ammonia pump; 36. Ammonium sulfate concentration oxidation tower; 37. Crystallizer; 38. Second weighing scale; 39. Second elevator; 40. Compound fertilizer granulation tower; 41. Granulation nozzle; 42. Fourth regulating valve; 43. Potassium chloride dissolving tank; 44. Third regulating valve; 45. Ammonium sulfate dissolving tank; 46. Fifth regulating valve; 47. First regulating valve; 48. Second regulating valve; 49. First three-way; 50. Urea solution pump; 51. Urea solution storage tank; 52. Potassium chloride warehouse; 53. First weighing scale; 54. First elevator; 55. Hot air pipeline; 56. Sulfur granulation device; 57. Ammonia pipeline. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is described in detail below in conjunction with the accompanying drawings. The description in this part is only exemplary and explanatory and should not have any limiting effect on the protection scope of the present invention.

[0033] like Figure 1As shown, the present invention is a comprehensive utilization device and comprehensive utilization method of acid gas in a synthetic ammonia device, wherein the device comprises a gasification system acid gas unit, a low-temperature methanol washing system acid gas unit and a shift stripping tower acid gas unit, wherein the gasification system acid gas unit is respectively connected to the heating gas inlet of the Claus combustion furnace 18 and the heating gas inlet of the waste gas combustion furnace 21 in the sulfur preparation unit; the low-temperature methanol washing system acid gas unit is connected to the inlet of the Claus combustion furnace 18, and the shift stripping tower acid gas unit is connected to the inlet of the waste gas combustion furnace 21; the top tail gas outlet of the waste gas combustion furnace 21 is connected to the tail gas treatment unit, the tail gas treatment unit is coupled to the ammonium sulfite solution preparation unit, and the ammonium sulfite solution preparation unit is connected to the ammonium sulfate preparation unit. The present invention provides a device for comprehensive and centralized treatment of multiple streams of acid gas in a synthetic ammonia device, which is specifically used for the acid gas produced in the acid gas unit of the gasification system, the acid gas unit of the low-temperature methanol washing system and the acid gas unit of the conversion stripping tower. By treating the above acid gas, not only can the defect caused by the production gas entering the flare be avoided, but also the characteristics of meeting the emission standards, being environmentally friendly, and producing ammonium sulfate as a by-product, thereby increasing the profit of the enterprise can be achieved. In the present invention, the above acid gas is deeply studied, and different components in different acid gases are treated separately, and the acid gas of the gasification system is treated separately. The CO and H2 contents in the gas are high, and the calorific value is high, so the gas can be used as fuel gas for incinerators and Claus burners, so as to save natural gas and other fuels and save operating costs, while achieving stable operation of the incinerator and Claus burner. The acid gas of the low-temperature methanol washing system is used to produce sulfur using a Claus reactor. Furthermore, the tail gas treatment unit in the present invention is coupled with the ammonium sulfite solution preparation unit to achieve the treatment of the tail gas and the emission of the tail gas in compliance with the standards while achieving the preparation of the ammonium sulfite solution, thus laying a foundation for the subsequent production of ammonium sulfate.

[0034] Furthermore, the tail gas treatment unit includes an ammonia absorption tower 29 connected to the tail gas outlet of the exhaust gas combustion furnace 21, the gas phase outlet at the top of the ammonia absorption tower 29 is connected to the inlet of the water washing tower 25, and the gas phase outlet at the top of the water washing tower 25 is connected to the atmosphere; the ammonium sulfite solution preparation unit includes a desalted water storage tank 30, the desalted water storage tank 30 is connected to the water washing tower 25 through the desalted water replenishment pump 23 and the eighth regulating valve 22, and the bottom outlet of the water washing tower 25 is connected to the circulation port at the top of the water washing tower 25 through the water washing tower bottom pump 27 A fifth tee 26 is provided between the water washing tower bottom pump 27 and the circulation port at the top of the water washing tower 25, and the third end of the fifth tee 26 is connected to the liquid inlet of the ammonia absorption tower 29 through the seventh regulating valve 28; the bottom outlet of the ammonia absorption tower 29 is connected to the circulation port at the top of the ammonia absorption tower 29 through the ammonia absorption tower bottom pump 33, and a fourth tee 32 is provided between the ammonia absorption tower bottom pump 33 and the circulation port at the top of the ammonia absorption tower 29, and the third end of the fourth tee 32 is connected to the ammonium sulfate concentration oxidation tower 36 through the sixth regulating valve 31. The coupling in the present invention refers to the use of the ammonia absorption tower 29 and the water washing tower 25 in the tail gas treatment unit to treat the tail gas to achieve the standard discharge of the tail gas, and at the same time, in the process of removing ammonia and sulfur by the water washing tower 25 and the ammonia absorption tower 29, the desalted water is gradually absorbed and concentrated to generate ammonium sulfite solution, which lays a foundation for the subsequent preparation of ammonium sulfate. Furthermore, the desalted water storage tank 30 is used to store desalted water. When the absorption liquid circulating in the water scrubber 25 is insufficient, it can be replenished through the desalted water storage tank 30 to meet the operation needs of the water scrubber 25 and ensure that the exhaust gas can meet the emission standards and be environmentally friendly.

[0035] Furthermore, the ammonia absorption tower 29 is provided with an ammonia absorption tower refilling port, which is connected to the ammonia tank 24 with the ammonia pipeline 57 through the ammonia pump 35. The present invention is particularly provided with the ammonia absorption tower refilling port for use when the water scrubber 25 cannot feed the absorption liquid into the ammonia absorption tower 29, and the amount of absorption liquid in the ammonia absorption tower 29 is small and cannot operate normally. The specific process can be to open the ammonia pump 35 to allow the ammonia in the ammonia tank 24 to enter the ammonia absorption tower 29, and the ammonia in the ammonia tank 24 can come from the ammonia pipeline 57.

[0036] Furthermore, the ammonium sulfate preparation unit includes an ammonium sulfate concentration oxidation tower 36, which is respectively connected to the dirty nitrogen gas exhaust pipe 34 and the hot air pipe 55 in the air separation system, the bottom outlet of the ammonium sulfate concentration oxidation tower 36 is connected to the crystallizer 37, the solid phase outlet of the crystallizer 37 is connected to the compound fertilizer production unit, and the liquid phase outlet of the crystallizer 37 is connected to the liquid replenishment port of the ammonia water tank 34; the top gas phase outlet of the ammonium sulfate concentration oxidation tower 36 is connected to the inlet of the water washing tower 25. The above-mentioned ammonium sulfite solution enters the ammonium sulfate concentration oxidation tower 36 for oxidation crystallization. The hot air in the hot air duct 55 takes away a part of the water vapor while oxidizing the ammonium sulfite, so as to concentrate the ammonium sulfate. The dirty nitrogen gas in the dirty nitrogen exhaust pipe 34 enters the ammonium sulfate concentration oxidation tower 36 to concentrate the ammonium sulfate for a second time. In order to achieve the characteristic that the ammonium sulfate enters the crystallizer 37 for crystallization after the second concentration, the mother liquor after crystallization in the crystallizer 37 can be sent to the ammonia water tank 34 for recycling through the liquid phase outlet, and the tail gas produced in the ammonium sulfate concentration oxidation tower 36 can enter the water washing tower 25 for washing and then discharged, so as to achieve the characteristic of being environmentally friendly.

[0037] Furthermore, the compound fertilizer production unit includes a compound fertilizer granulation tower 40, a urea solution storage tank 51, and a potassium chloride warehouse 52; the compound fertilizer granulation tower 40 includes a granulation nozzle 41 arranged in the middle and upper part of the compound fertilizer granulation tower 40, and the inlet of the granulation nozzle 41 is connected to the outlets of the potassium chloride dissolving tank 43 and the ammonium sulfate dissolving tank 45 through the fourth regulating valve 42 and the fifth regulating valve 46 respectively, and the solid phase inlet of the potassium chloride dissolving tank 43 is connected to the potassium chloride warehouse 52 through the first hoist 54 and the first weighing scale 53, and the solid phase inlet of the ammonium sulfate dissolving tank 45 is connected to the potassium chloride warehouse 52 through the first hoist 54 and the first weighing scale 53. The second elevator 39 and the second weighing scale 38 are connected to the solid phase outlet of the crystallizer 37; the liquid phase outlets of the potassium chloride dissolving tank 43 and the ammonium sulfate dissolving tank 45 are connected to the first tee 49 through the respective first regulating valves 47 and the second regulating valves 48, and the third end of the first tee 49 is connected to the outlet of the urea solution storage tank 51 through the urea solution pump 50; the setting height of the potassium chloride dissolving tank 43 is greater than the setting height of the ammonium sulfate dissolving tank 45, and the outlet of the potassium chloride dissolving tank 43 is connected to the inlet of the ammonium sulfate dissolving tank 45 through the third regulating valve 44. After the ammonium sulfate is prepared in the present invention, it can be sent to the compound fertilizer production unit for preparing compound fertilizer. The above-mentioned device is capable of preparing sulfur-nitrogen binary compound fertilizer, nitrogen-potassium binary compound fertilizer and sulfur-nitrogen-potassium ternary compound fertilizer. When preparing sulfur-nitrogen binary compound fertilizer and sulfur-nitrogen-potassium ternary compound fertilizer, the ammonium sulfate produced can be used to reduce the cost of compound fertilizer production for the enterprise and realize the characteristics of circular economy. When used to produce nitrogen-potassium binary compound fertilizer, the ammonium sulfate can be sold to increase the profit of the enterprise.

[0038] Furthermore, the gasification system acid gas unit includes a gasification high-temperature flash tank 1, a gas phase outlet at the top of the gasification high-temperature flash tank 1 is connected to a gas phase inlet at the bottom of a gasification high-temperature hot water tower 3, a gasification low-temperature ash water pipeline 2 is provided at the upper part of the gasification high-temperature hot water tower 3, a gas phase outlet at the top of the gasification high-temperature hot water tower 3 is connected to a first acid gas cooler 5, a liquid phase outlet of the first acid gas cooler 5 is connected to a gasification clarification tank 6, and a gas phase outlet of the first acid gas cooler 5 is connected to a heating gas inlet of a Claus burner 18 and a heating gas inlet of a waste gas burner 21 through a third tee 16, respectively. The acid gas from the acid gas unit of the gasification system contains sulfur. If it is directly sent to the flare for combustion, pollution problems will occur. However, the acid gas has the characteristics of high calorific value, and in the process of exhaust gas treatment after combustion in the exhaust gas combustion furnace 21, it can be absorbed in the process of removing sulfur to form ammonium sulfite. At the same time, the acid gas has the characteristics of high calorific value, and it can replace conventional heating combustible gas to achieve the characteristic of reducing costs.

[0039] Furthermore, a second three-way valve 11 and a tenth regulating valve 15 are sequentially arranged between the gas phase outlet of the first acid gas cooler 5 and the third three-way valve 16, and the third end of the second three-way valve 11 is sequentially connected to the conversion furnace 14 in the conversion system through the ninth regulating valve 12 and the fuel gas compressor 13; an eleventh regulating valve 17 is arranged between the third three-way valve 16 and the hot gas inlet of the Claus combustion furnace 18. The acid gas components of the acid gas unit of the gasification system have high contents of CO and H2, which can be sent to the conversion furnace in the conversion system by setting the fuel gas compressor 13 and used as raw materials for conversion reaction, so as to achieve the characteristics of saving coal consumption and reducing production costs.

[0040] Furthermore, the low-temperature methanol washing system acid gas unit includes a methanol washing heat regenerator 9, the gas phase outlet of the methanol washing heat regenerator 9 is connected to the acid gas liquid separator 15 through the second acid gas cooler 10, and the gas phase outlet of the acid gas liquid separator 15 is connected to the raw gas inlet of the Claus combustion furnace 18; the shift stripping tower acid gas unit includes a low-pressure flash tank 4, the gas phase outlet of the low-pressure flash tank 4 is connected to the gas phase inlet of the lower part of the shift stripping tower 7, the upper inlet of the shift stripping tower 7 is connected to the shift ammonia washing tower waste liquid pipeline 8, and the gas phase outlet of the top of the shift stripping tower 7 is connected to the inlet of the waste gas combustion furnace 21. The low-temperature methanol washing system acid gas is used to make sulfur in the Claus reactor, and the tail gas after sulfur production still contains a trace amount of sulfur dioxide. Direct discharge does not meet environmental protection requirements. Therefore, an incinerator is used to burn it with the shift stripping acid gas and then sent to the ammonia absorption device to absorb sulfur dioxide, and ammonium sulfite is formed after absorption, and then the ammonium sulfite is oxidized to ammonium sulfate.

[0041] Furthermore, the sulfur preparation unit includes a Claus combustion furnace 18, the outlet of the Claus combustion furnace 18 is connected to the inlet of the Claus reactor 19, the liquid phase outlet of the Claus reactor 19 is connected to the sulfur warehouse 20 through the sulfur granulation device 56, and the gas phase outlet of the Claus reactor 19 is connected to the inlet of the exhaust gas combustion furnace 21. The acid gas of the low-temperature methanol washing system is used to make sulfur in the Claus reactor. The tail gas after sulfur making still contains a trace amount of sulfur dioxide, and direct discharge does not meet environmental protection requirements. Therefore, an incinerator is used to burn it with the shift stripping acid gas and then sent to the tail gas treatment unit to absorb sulfur dioxide to form ammonium sulfite.

[0042] The present invention also provides a method for comprehensive utilization of acid gas from a synthetic ammonia device, the method comprising the following steps:

[0043] Step 1: The high-temperature black water in the gasification system enters the gasification high-temperature flash tank 1 for flash evaporation. The flashed gas phase enters the gasification high-temperature hot water tower 3 to transfer mass and heat with the gasification low-temperature ash water from the gasification low-temperature ash water pipeline 2. The non-condensable gas and part of the water vapor that are not absorbed enter the first acid gas cooler 5 for condensation. The condensed liquid phase enters the gasification clarification tank 6 for repeated use as gasification circulating water. The uncondensed acid gas enters the second three-way valve 11. One way is sent to the fuel gas compressor 13 through the ninth regulating valve 12 for pressurization. After the pressure is increased to 6.3 MPa (G), it is sent to the conversion furnace 14 in the conversion system as a raw material for recycling. The other way enters the third three-way valve 16 through the first regulating valve 15, and enters the exhaust gas combustion furnace 21 and the Claus combustion furnace 18 respectively for use as fuel gas.

[0044] Step 2: The low-pressure steam from the low-pressure flash tank 4 of the gasification system enters the conversion stripping tower 7 as the stripping heat source of the conversion stripping tower 7, and is countercurrently contacted with the conversion ammonia washing tower waste liquid from the conversion ammonia washing tower waste liquid pipeline 8, so as to strip out the acid gas in the conversion ammonia washing tower waste liquid, and the stripped acid gas enters the waste gas combustion furnace 21 for incineration treatment;

[0045] Step 3: The acid gas from the methanol heat washing regenerator 9 enters the second acid gas cooler 10 for condensation, and the methanol and water in the acid gas are condensed out. The condensed acid gas enters the acid gas separator 15 for separation, and the separated gas phase enters the Claus combustion furnace 18 for combustion;

[0046] Step 4: The acid gas in the above steps 1 and 3 enters the Claus combustion furnace 18 for combustion, partially converts hydrogen sulfate into sulfur dioxide, and then enters the Claus reactor 19 for hydrogen sulfide and sulfur dioxide to react to produce liquid sulfur, the liquid sulfur enters the sulfur granulation device 56 for granulation, and the granulated sulfur enters the sulfur warehouse 20 for packaging and sales; the tail gas produced in the Claus reactor 19 enters the exhaust gas combustion furnace 21 for incineration treatment; the tail gas produced in the above Claus reactor 19 contains some carbon monoxide and sulfur dioxide that are not fully reacted;

[0047] Step 5: The acid gas in the aforementioned step 1, the acid gas in step 2, and the tail gas produced in the Claus reactor 19 in step 4 enter the exhaust gas combustion furnace 21 for full combustion, and the tail gas of the exhaust gas combustion furnace 21 enters the ammonia absorption tower 29, and the sulfur dioxide in the tail gas is absorbed by the ammonia absorption tower 29. The tail gas after the ammonia absorption enters the water washing tower 25 for washing and then meets the emission standards;

[0048] Step 6: The desalted water in the desalted water storage tank 30 is pressurized by the desalted water replenishment pump 23 and sent to the water washing tower 25 to wash the tail gas after ammonia absorption, and the eighth regulating valve 22 is used to adjust the amount of desalted water entering the water washing tower 25; the solution at the bottom of the water washing tower 25 is pressurized by the water washing tower bottom pump 27 and then refluxed to the water washing tower 25 from the circulation port at the top of the water washing tower 25, so as to control the mass concentration of ammonia in the solution within 5% under the premise of saving water, so as to facilitate the entry into the subsequent ammonia absorption tower 29 under the premise of ensuring qualified tail gas emissions; when it is necessary to replenish desalted water, the desalted water replenishment pump 23 and the eighth regulating valve 22 can be opened;

[0049] Step 7: When the solution in step 6 reaches a predetermined threshold, the seventh regulating valve 28 is opened to allow the solution in the fifth three-way valve 26 to enter the ammonia absorption tower 29 for use as an absorption liquid. The solution at the bottom of the ammonia absorption tower 29 is pressurized by the ammonia absorption tower bottom pump 33 and then refluxed from the circulation port at the upper part of the ammonia absorption tower 29 to the ammonia absorption tower 29 for recycling, so as to lay a foundation for entering the subsequent ammonium sulfate concentration oxidation tower 36 under the premise of the absorption liquid. When the absorption liquid needs to be supplemented and the solution in step 6 does not reach the predetermined threshold, the ammonia pump 35 is turned on to allow the ammonia tank 24 with the ammonia pipeline 57 to supplement ammonia as the absorption liquid into the ammonia absorption tower 29;

[0050] Step 8: When the solution in step 7 reaches a predetermined threshold, the sixth regulating valve 31 is opened to allow the ammonium sulfite solution in the fourth three-way valve 32 to enter the ammonium sulfate concentration oxidation tower 36 for oxidation crystallization. The hot air in the hot air pipe 55 takes away a portion of water vapor while oxidizing the ammonium sulfite, thereby concentrating the ammonium sulfate; the dirty nitrogen gas in the dirty nitrogen gas exhaust pipe 34 enters the ammonium sulfate concentration oxidation tower 36 to conduct secondary concentration of the ammonium sulfate; after the secondary concentration, the ammonium sulfate enters the crystallizer 37 for crystallization, and the mother liquor after crystallization enters the ammonia water tank 24 to be used as the absorption liquid of the ammonia water absorption tower 29;

[0051] Step 9: The solid phase crystallized by the crystallizer 37 in step 8 passes through the second weighing scale 38 and the second elevator 39 and enters the ammonium sulfate dissolving tank 45 inside the compound fertilizer granulation tower 40 to be used for preparing compound fertilizer;

[0052] Step 10: When sulfur-nitrogen binary compound fertilizer needs to be prepared, the first regulating valve 47, the fourth regulating valve 42 and the third regulating valve 44 are closed, and the second regulating valve 48 and the fifth regulating valve 46 are opened. The urea solution in the urea solution storage tank (51) enters the ammonium sulfate dissolving tank 45 through the urea solution pump 50, so that the urea solution with a concentration of 99% dissolves the ammonium sulfate, and after the dissolution, the ammonium sulfate enters the granulation nozzle 41 for granulation;

[0053] Step 11: When it is necessary to prepare sulfur-nitrogen-potassium ternary compound fertilizer, the first regulating valve 47, the second regulating valve 48, the third regulating valve 44 and the fifth regulating valve 46 are opened, and the fourth regulating valve 42 is closed. The potassium chloride in the potassium chloride warehouse 52 enters the potassium chloride dissolving tank 43 through the first weighing scale 53 and the first elevator 54, and the urea solution in the urea solution storage tank 51 enters the potassium chloride dissolving tank 43 and the ammonium sulfate dissolving tank 45 respectively through the urea solution pump 50, so that the urea solution with a concentration of 99% dissolves the potassium chloride and ammonium sulfate respectively, and the urea solution containing potassium chloride after dissolution enters the ammonium sulfate dissolving tank 45 by utilizing the height difference for mixing to obtain compound fertilizer slurry; the compound fertilizer slurry enters the granulation nozzle 41 for granulation;

[0054] Step 12: When it is necessary to prepare nitrogen-potassium binary compound fertilizer, the solid phase crystallized by the crystallizer 37 in step 8 is dried and then sold; the second regulating valve 48, the third regulating valve 44 and the fifth regulating valve 46 are closed, the first regulating valve 47 and the fourth regulating valve 42 are opened, and the urea solution in the urea solution storage tank 51 enters the potassium chloride dissolving tank 43 through the urea solution pump 50, so that the urea solution with a concentration of 99% dissolves the potassium chloride, and after dissolution, it enters the granulation nozzle 41 for granulation.

[0055] The present invention combines different acid gas treatment devices in the original synthetic ammonia device into the present system, which is not only convenient for operation and control, but also enables different acid gases to achieve standard emission in the end. Meanwhile, the different components of various acid gases are used for targeted design. The acid gas of the gasification system has high CO and H2 content and contains sulfur. According to the above characteristics, it can be used as raw material in the conversion furnace to save coal consumption; it can also be used as fuel gas for incinerators and Claus combustion furnaces, and can also absorb sulfur in the tail gas treatment process to form ammonium sulfite after absorption; further, the acid gas of the low-temperature methanol washing system is used to prepare sulfur, and the tail gas still contains a trace amount of sulfur dioxide, which does not meet environmental protection requirements if it is directly discharged. Therefore, an incinerator is used to incinerate it with the conversion stripping acid gas and then send it to the ammonia absorption device to absorb sulfur dioxide to form ammonium sulfite after absorption, and then the ammonium sulfite is oxidized to ammonium sulfate; the above processes are all realized by utilizing the different characteristics of different components of the acid gas. In the present invention, all acid gases can be treated by recycling or burning, and the tail gas is treated to achieve standard discharge. At the same time, the waste liquid is also recycled, especially by coupling the tail gas treatment unit with the ammonium sulfite solution preparation unit, which lays a foundation for the preparation of ammonium sulfate and can be used to prepare compound fertilizer to achieve a circular economy model.

[0056] In order to explain the present invention in more detail, the present invention is further described in conjunction with embodiments. Specific embodiments are as follows:

[0057] Example 1

[0058] A synthetic ammonia unit acid gas comprehensive utilization device comprises a gasification system acid gas unit, a low temperature methanol washing system acid gas unit and a shift stripping tower acid gas unit, wherein the gasification system acid gas unit is respectively connected to the tracing gas inlet of the Claus combustion furnace 18 and the tracing gas inlet of the waste gas combustion furnace 21 in the sulfur preparation unit; the low temperature methanol washing system acid gas unit is connected to the inlet of the Claus combustion furnace 18, and the shift stripping tower acid gas unit is connected to the inlet of the waste gas combustion furnace 21; the top tail gas outlet of the waste gas combustion furnace 21 is connected to the tail gas treatment unit, the tail gas treatment unit is coupled to the ammonium sulfite solution preparation unit, and the ammonium sulfite solution preparation unit is connected to the ammonium sulfate preparation unit. The tail gas treatment unit includes an ammonia absorption tower 29 connected to the tail gas outlet of the exhaust gas combustion furnace 21, the gas phase outlet at the top of the ammonia absorption tower 29 is connected to the inlet of the water washing tower 25, and the gas phase outlet at the top of the water washing tower 25 is connected to the atmosphere; the ammonium sulfite solution preparation unit includes a desalted water storage tank 30, the desalted water storage tank 30 is connected to the water washing tower 25 through a desalted water replenishment pump 23 and an eighth regulating valve 22, and the bottom outlet of the water washing tower 25 is connected to the circulation port at the top of the water washing tower 25 through a water washing tower bottom pump 27. A fifth tee 26 is provided between the washing tower bottom pump 27 and the circulation port at the top of the washing tower 25, and the third end of the fifth tee 26 is connected to the liquid inlet of the ammonia absorption tower 29 through the seventh regulating valve 28; the bottom outlet of the ammonia absorption tower 29 is connected to the circulation port at the top of the ammonia absorption tower 29 through the ammonia absorption tower bottom pump 33, and a fourth tee 32 is provided between the ammonia absorption tower bottom pump 33 and the circulation port at the top of the ammonia absorption tower 29, and the third end of the fourth tee 32 is connected to the ammonium sulfate concentration oxidation tower 36 through the sixth regulating valve 31. The ammonia absorption tower 29 is provided with an ammonia absorption tower replenishing port, and the ammonia absorption tower replenishing port is connected to the ammonia tank 24 with an ammonia pipeline 57 through the ammonia pump 35. The ammonium sulfate preparation unit includes an ammonium sulfate concentration oxidation tower 36, which is respectively connected to the dirty nitrogen gas exhaust pipe 34 and the hot air pipe 55 in the air separation system, the bottom outlet of the ammonium sulfate concentration oxidation tower 36 is connected to the crystallizer 37, the solid phase outlet of the crystallizer 37 is connected to the compound fertilizer production unit, and the liquid phase outlet of the crystallizer 37 is connected to the liquid replenishment port of the ammonia water tank 34; the top gas phase outlet of the ammonium sulfate concentration oxidation tower 36 is connected to the inlet of the water washing tower 25.The compound fertilizer production unit includes a compound fertilizer granulation tower 40, a urea solution storage tank 51, and a potassium chloride warehouse 52; the compound fertilizer granulation tower 40 includes a granulation nozzle 41 arranged at the middle and upper part of the compound fertilizer granulation tower 40, the inlet of the granulation nozzle 41 is connected to the outlets of the potassium chloride dissolving tank 43 and the ammonium sulfate dissolving tank 45 through the fourth regulating valve 42 and the fifth regulating valve 46 respectively, the solid phase inlet of the potassium chloride dissolving tank 43 is connected to the potassium chloride warehouse 52 through the first hoist 54 and the first weighing scale 53, and the solid phase inlet of the ammonium sulfate dissolving tank 45 is connected to the potassium chloride warehouse 52 through the second hoist 54 and the first weighing scale 53. The elevator 39 and the second weighing scale 38 are connected to the solid phase outlet of the crystallizer 37; the liquid phase outlets of the potassium chloride dissolving tank 43 and the ammonium sulfate dissolving tank 45 are respectively connected to the first three-way valve 49 through the corresponding first regulating valve 47 and the second regulating valve 48, and the third end of the first three-way valve 49 is connected to the outlet of the urea solution storage tank 51 through the urea solution pump 50; the setting height of the potassium chloride dissolving tank 43 is greater than the setting height of the ammonium sulfate dissolving tank 45, and the outlet of the potassium chloride dissolving tank 43 is connected to the inlet of the ammonium sulfate dissolving tank 45 through the third regulating valve 44. The gasification system acid gas unit comprises a gasification high temperature flash tank 1, the gas phase outlet at the top of the gasification high temperature flash tank 1 is connected to the gas phase inlet at the bottom of the gasification high temperature hot water tower 3, the upper part of the gasification high temperature hot water tower 3 is provided with a gasification low temperature ash water pipeline 2, the gas phase outlet at the top of the gasification high temperature hot water tower 3 is connected to the first acid gas cooler 5, the liquid phase outlet of the first acid gas cooler 5 is connected to the gasification clarification tank 6, and the gas phase outlet of the first acid gas cooler 5 is respectively connected to the heat gas inlet of the Claus combustion furnace 18 and the heat gas inlet of the exhaust gas combustion furnace 21 through the third three-way 16. A second three-way 11 and a tenth regulating valve 15 are arranged in sequence between the gas phase outlet of the first acid gas cooler 5 and the third three-way 16, and the third end of the second three-way 11 is connected to the conversion furnace 14 in the conversion system through the ninth regulating valve 12 and the fuel gas compressor 13; an eleventh regulating valve 17 is arranged between the third three-way 16 and the heat gas inlet of the Claus combustion furnace 18. The low temperature methanol washing system acid gas unit comprises a methanol washing heat regenerator 9, the gas phase outlet of the methanol washing heat regenerator 9 is connected to the acid gas liquid separator 15 through the second acid gas cooler 10, and the gas phase outlet of the acid gas liquid separator 15 is connected to the raw gas inlet of the Claus combustion furnace 18; the shift stripping tower acid gas unit comprises a low pressure flash tank 4, the gas phase outlet of the low pressure flash tank 4 is connected to the gas phase inlet of the lower part of the shift stripping tower 7, the upper inlet of the shift stripping tower 7 is connected to the shift ammonia washing tower waste liquid pipeline 8, and the gas phase outlet of the top of the shift stripping tower 7 is connected to the inlet of the waste gas combustion furnace 21. The sulfur preparation unit comprises a Claus combustion furnace 18, the outlet of the Claus combustion furnace 18 is connected to the inlet of the Claus reactor 19, the liquid phase outlet of the Claus reactor 19 is connected to the sulfur warehouse 20 through the sulfur granulation device 56, and the gas phase outlet of the Claus reactor 19 is connected to the inlet of the waste gas combustion furnace 21.

[0059] The present invention also provides a method for comprehensive utilization of acid gas from a synthetic ammonia device, the method comprising the following steps:

[0060] Step 1: The high-temperature black water in the gasification system enters the gasification high-temperature flash tank 1 for flash evaporation. The flashed gas phase enters the gasification high-temperature hot water tower 3 to transfer mass and heat with the gasification low-temperature ash water from the gasification low-temperature ash water pipeline 2. The non-condensable gas and part of the water vapor that are not absorbed enter the first acid gas cooler 5 for condensation. The condensed liquid phase enters the gasification clarification tank 6 for repeated use as gasification circulating water. The uncondensed acid gas enters the second three-way valve 11. One way is sent to the fuel gas compressor 13 through the ninth regulating valve 12 for pressurization. After the pressure is increased to 6.3 MPa (G), it is sent to the conversion furnace 14 in the conversion system as a raw material for recycling. The other way enters the third three-way valve 16 through the first regulating valve 15, and enters the exhaust gas combustion furnace 21 and the Claus combustion furnace 18 respectively for use as fuel gas.

[0061] Step 2: The low-pressure steam from the low-pressure flash tank 4 of the gasification system enters the conversion stripping tower 7 as the stripping heat source of the conversion stripping tower 7, and is countercurrently contacted with the conversion ammonia washing tower waste liquid from the conversion ammonia washing tower waste liquid pipeline 8, so as to strip out the acid gas in the conversion ammonia washing tower waste liquid, and the stripped acid gas enters the waste gas combustion furnace 21 for incineration treatment;

[0062] Step 3: The acid gas from the methanol heat washing regenerator 9 enters the second acid gas cooler 10 for condensation, and the methanol and water in the acid gas are condensed out. The condensed acid gas enters the acid gas separator 15 for separation, and the separated gas phase enters the Claus combustion furnace 18 for combustion;

[0063] Step 4: The acid gas in the above steps 1 and 3 enters the Claus combustion furnace 18 for combustion, partially converts hydrogen sulfate into sulfur dioxide, and then enters the Claus reactor 19 for hydrogen sulfide and sulfur dioxide to react to produce liquid sulfur, the liquid sulfur enters the sulfur granulation device 56 for granulation, and the granulated sulfur enters the sulfur warehouse 20 for packaging and sales; the tail gas produced in the Claus reactor 19 enters the exhaust gas combustion furnace 21 for incineration treatment; the tail gas produced in the above Claus reactor 19 contains some carbon monoxide and sulfur dioxide that are not fully reacted;

[0064] Step 5: The acid gas in the aforementioned step 1, the acid gas in step 2, and the tail gas produced in the Claus reactor 19 in step 4 enter the exhaust gas combustion furnace 21 for full combustion, and the tail gas of the exhaust gas combustion furnace 21 enters the ammonia absorption tower 29, and the sulfur dioxide in the tail gas is absorbed by the ammonia absorption tower 29. The tail gas after the ammonia absorption enters the water washing tower 25 for washing and then meets the emission standards;

[0065] Step 6: The desalted water in the desalted water storage tank 30 is pressurized by the desalted water replenishment pump 23 and sent to the water washing tower 25 to wash the tail gas after ammonia absorption, and the eighth regulating valve 22 is used to adjust the amount of desalted water entering the water washing tower 25; the solution at the bottom of the water washing tower 25 is pressurized by the water washing tower bottom pump 27 and then refluxed to the water washing tower 25 from the circulation port at the top of the water washing tower 25, so as to control the mass concentration of ammonia in the solution within 5% under the premise of saving water, so as to facilitate the entry into the subsequent ammonia absorption tower 29 under the premise of ensuring qualified tail gas emissions; when it is necessary to replenish desalted water, the desalted water replenishment pump 23 and the eighth regulating valve 22 can be opened;

[0066] Step 7: When the solution in step 6 reaches a predetermined threshold, the seventh regulating valve 28 is opened to allow the solution in the fifth three-way valve 26 to enter the ammonia absorption tower 29 for use as an absorption liquid. The solution at the bottom of the ammonia absorption tower 29 is pressurized by the ammonia absorption tower bottom pump 33 and then refluxed from the circulation port at the upper part of the ammonia absorption tower 29 to the ammonia absorption tower 29 for recycling, so as to lay a foundation for entering the subsequent ammonium sulfate concentration oxidation tower 36 under the premise of the absorption liquid. When the absorption liquid needs to be supplemented and the solution in step 6 does not reach the predetermined threshold, the ammonia pump 35 is turned on to allow the ammonia tank 24 with the ammonia pipeline 57 to supplement ammonia as the absorption liquid into the ammonia absorption tower 29;

[0067] Step 8: When the solution in step 7 reaches a predetermined threshold, the sixth regulating valve 31 is opened to allow the ammonium sulfite solution in the fourth three-way valve 32 to enter the ammonium sulfate concentration oxidation tower 36 for oxidation crystallization. The hot air in the hot air pipe 55 takes away a portion of water vapor while oxidizing the ammonium sulfite, thereby concentrating the ammonium sulfate; the dirty nitrogen gas in the dirty nitrogen gas exhaust pipe 34 enters the ammonium sulfate concentration oxidation tower 36 to conduct secondary concentration of the ammonium sulfate; after the secondary concentration, the ammonium sulfate enters the crystallizer 37 for crystallization, and the mother liquor after crystallization enters the ammonia water tank 24 to be used as the absorption liquid of the ammonia water absorption tower 29;

[0068] Step 9: The solid phase crystallized by the crystallizer 37 in step 8 passes through the second weighing scale 38 and the second elevator 39 and enters the ammonium sulfate dissolving tank 45 inside the compound fertilizer granulation tower 40 to be used for preparing compound fertilizer;

[0069] Step 10: When it is necessary to prepare sulfur-nitrogen binary compound fertilizer, the first regulating valve 47, the fourth regulating valve 42 and the third regulating valve 44 are closed, and the second regulating valve 48 and the fifth regulating valve 46 are opened. The urea solution in the urea solution storage tank (51) enters the ammonium sulfate dissolving tank 45 through the urea solution pump 50, so that the urea solution with a concentration of 99% dissolves the ammonium sulfate. After dissolution, the ammonium sulfate enters the granulation nozzle 41 for granulation.

[0070] Example 2

[0071] A synthetic ammonia unit acid gas comprehensive utilization device comprises a gasification system acid gas unit, a low temperature methanol washing system acid gas unit and a shift stripping tower acid gas unit, wherein the gasification system acid gas unit is respectively connected to the tracing gas inlet of the Claus combustion furnace 18 and the tracing gas inlet of the waste gas combustion furnace 21 in the sulfur preparation unit; the low temperature methanol washing system acid gas unit is connected to the inlet of the Claus combustion furnace 18, and the shift stripping tower acid gas unit is connected to the inlet of the waste gas combustion furnace 21; the top tail gas outlet of the waste gas combustion furnace 21 is connected to the tail gas treatment unit, the tail gas treatment unit is coupled to the ammonium sulfite solution preparation unit, and the ammonium sulfite solution preparation unit is connected to the ammonium sulfate preparation unit. The tail gas treatment unit includes an ammonia absorption tower 29 connected to the tail gas outlet of the exhaust gas combustion furnace 21, the gas phase outlet at the top of the ammonia absorption tower 29 is connected to the inlet of the water washing tower 25, and the gas phase outlet at the top of the water washing tower 25 is connected to the atmosphere; the ammonium sulfite solution preparation unit includes a desalted water storage tank 30, the desalted water storage tank 30 is connected to the water washing tower 25 through a desalted water replenishment pump 23 and an eighth regulating valve 22, and the bottom outlet of the water washing tower 25 is connected to the circulation port at the top of the water washing tower 25 through a water washing tower bottom pump 27. A fifth tee 26 is provided between the washing tower bottom pump 27 and the circulation port at the top of the washing tower 25, and the third end of the fifth tee 26 is connected to the liquid inlet of the ammonia absorption tower 29 through the seventh regulating valve 28; the bottom outlet of the ammonia absorption tower 29 is connected to the circulation port at the top of the ammonia absorption tower 29 through the ammonia absorption tower bottom pump 33, and a fourth tee 32 is provided between the ammonia absorption tower bottom pump 33 and the circulation port at the top of the ammonia absorption tower 29, and the third end of the fourth tee 32 is connected to the ammonium sulfate concentration oxidation tower 36 through the sixth regulating valve 31. The ammonia absorption tower 29 is provided with an ammonia absorption tower replenishing port, and the ammonia absorption tower replenishing port is connected to the ammonia tank 24 with an ammonia pipeline 57 through the ammonia pump 35. The ammonium sulfate preparation unit includes an ammonium sulfate concentration oxidation tower 36, which is respectively connected to the dirty nitrogen gas exhaust pipe 34 and the hot air pipe 55 in the air separation system, the bottom outlet of the ammonium sulfate concentration oxidation tower 36 is connected to the crystallizer 37, the solid phase outlet of the crystallizer 37 is connected to the compound fertilizer production unit, and the liquid phase outlet of the crystallizer 37 is connected to the liquid replenishment port of the ammonia water tank 34; the top gas phase outlet of the ammonium sulfate concentration oxidation tower 36 is connected to the inlet of the water washing tower 25.The compound fertilizer production unit includes a compound fertilizer granulation tower 40, a urea solution storage tank 51, and a potassium chloride warehouse 52; the compound fertilizer granulation tower 40 includes a granulation nozzle 41 arranged at the middle and upper part of the compound fertilizer granulation tower 40, the inlet of the granulation nozzle 41 is connected to the outlets of the potassium chloride dissolving tank 43 and the ammonium sulfate dissolving tank 45 through the fourth regulating valve 42 and the fifth regulating valve 46 respectively, the solid phase inlet of the potassium chloride dissolving tank 43 is connected to the potassium chloride warehouse 52 through the first hoist 54 and the first weighing scale 53, and the solid phase inlet of the ammonium sulfate dissolving tank 45 is connected to the potassium chloride warehouse 52 through the second hoist 54 and the first weighing scale 53. The elevator 39 and the second weighing scale 38 are connected to the solid phase outlet of the crystallizer 37; the liquid phase outlets of the potassium chloride dissolving tank 43 and the ammonium sulfate dissolving tank 45 are respectively connected to the first three-way valve 49 through the corresponding first regulating valve 47 and the second regulating valve 48, and the third end of the first three-way valve 49 is connected to the outlet of the urea solution storage tank 51 through the urea solution pump 50; the setting height of the potassium chloride dissolving tank 43 is greater than the setting height of the ammonium sulfate dissolving tank 45, and the outlet of the potassium chloride dissolving tank 43 is connected to the inlet of the ammonium sulfate dissolving tank 45 through the third regulating valve 44. The gasification system acid gas unit comprises a gasification high temperature flash tank 1, the gas phase outlet at the top of the gasification high temperature flash tank 1 is connected to the gas phase inlet at the bottom of the gasification high temperature hot water tower 3, the upper part of the gasification high temperature hot water tower 3 is provided with a gasification low temperature ash water pipeline 2, the gas phase outlet at the top of the gasification high temperature hot water tower 3 is connected to the first acid gas cooler 5, the liquid phase outlet of the first acid gas cooler 5 is connected to the gasification clarification tank 6, and the gas phase outlet of the first acid gas cooler 5 is respectively connected to the heat gas inlet of the Claus combustion furnace 18 and the heat gas inlet of the exhaust gas combustion furnace 21 through the third three-way 16. A second three-way 11 and a tenth regulating valve 15 are arranged in sequence between the gas phase outlet of the first acid gas cooler 5 and the third three-way 16, and the third end of the second three-way 11 is connected to the conversion furnace 14 in the conversion system through the ninth regulating valve 12 and the fuel gas compressor 13; an eleventh regulating valve 17 is arranged between the third three-way 16 and the heat gas inlet of the Claus combustion furnace 18. The low temperature methanol washing system acid gas unit comprises a methanol washing heat regenerator 9, the gas phase outlet of the methanol washing heat regenerator 9 is connected to the acid gas liquid separator 15 through the second acid gas cooler 10, and the gas phase outlet of the acid gas liquid separator 15 is connected to the raw gas inlet of the Claus combustion furnace 18; the shift stripping tower acid gas unit comprises a low pressure flash tank 4, the gas phase outlet of the low pressure flash tank 4 is connected to the gas phase inlet of the lower part of the shift stripping tower 7, the upper inlet of the shift stripping tower 7 is connected to the shift ammonia washing tower waste liquid pipeline 8, and the gas phase outlet of the top of the shift stripping tower 7 is connected to the inlet of the waste gas combustion furnace 21. The sulfur preparation unit comprises a Claus combustion furnace 18, the outlet of the Claus combustion furnace 18 is connected to the inlet of the Claus reactor 19, the liquid phase outlet of the Claus reactor 19 is connected to the sulfur warehouse 20 through the sulfur granulation device 56, and the gas phase outlet of the Claus reactor 19 is connected to the inlet of the waste gas combustion furnace 21.

[0072] The present invention also provides a method for comprehensive utilization of acid gas from a synthetic ammonia device, the method comprising the following steps:

[0073] Step 1: The high-temperature black water in the gasification system enters the gasification high-temperature flash tank 1 for flash evaporation. The flashed gas phase enters the gasification high-temperature hot water tower 3 to transfer mass and heat with the gasification low-temperature ash water from the gasification low-temperature ash water pipeline 2. The non-condensable gas and part of the water vapor that are not absorbed enter the first acid gas cooler 5 for condensation. The condensed liquid phase enters the gasification clarification tank 6 for repeated use as gasification circulating water. The uncondensed acid gas enters the second three-way valve 11. One way is sent to the fuel gas compressor 13 through the ninth regulating valve 12 for pressurization. After the pressure is increased to 6.3 MPa (G), it is sent to the conversion furnace 14 in the conversion system as a raw material for recycling. The other way enters the third three-way valve 16 through the first regulating valve 15, and enters the exhaust gas combustion furnace 21 and the Claus combustion furnace 18 respectively for use as fuel gas.

[0074] Step 2: The low-pressure steam from the low-pressure flash tank 4 of the gasification system enters the conversion stripping tower 7 as the stripping heat source of the conversion stripping tower 7, and is countercurrently contacted with the conversion ammonia washing tower waste liquid from the conversion ammonia washing tower waste liquid pipeline 8, so as to strip out the acid gas in the conversion ammonia washing tower waste liquid, and the stripped acid gas enters the waste gas combustion furnace 21 for incineration treatment;

[0075] Step 3: The acid gas from the methanol heat washing regenerator 9 enters the second acid gas cooler 10 for condensation, and the methanol and water in the acid gas are condensed out. The condensed acid gas enters the acid gas separator 15 for separation, and the separated gas phase enters the Claus combustion furnace 18 for combustion;

[0076] Step 4: The acid gas in the above steps 1 and 3 enters the Claus combustion furnace 18 for combustion, partially converts hydrogen sulfate into sulfur dioxide, and then enters the Claus reactor 19 for hydrogen sulfide and sulfur dioxide to react to produce liquid sulfur, the liquid sulfur enters the sulfur granulation device 56 for granulation, and the granulated sulfur enters the sulfur warehouse 20 for packaging and sales; the tail gas produced in the Claus reactor 19 enters the exhaust gas combustion furnace 21 for incineration treatment; the tail gas produced in the above Claus reactor 19 contains some carbon monoxide and sulfur dioxide that are not fully reacted;

[0077] Step 5: The acid gas in the aforementioned step 1, the acid gas in step 2, and the tail gas produced in the Claus reactor 19 in step 4 enter the exhaust gas combustion furnace 21 for full combustion, and the tail gas of the exhaust gas combustion furnace 21 enters the ammonia absorption tower 29, and the sulfur dioxide in the tail gas is absorbed by the ammonia absorption tower 29. The tail gas after the ammonia absorption enters the water washing tower 25 for washing and then meets the emission standards;

[0078] Step 6: The desalted water in the desalted water storage tank 30 is pressurized by the desalted water replenishment pump 23 and sent to the water washing tower 25 to wash the tail gas after ammonia absorption, and the eighth regulating valve 22 is used to adjust the amount of desalted water entering the water washing tower 25; the solution at the bottom of the water washing tower 25 is pressurized by the water washing tower bottom pump 27 and then refluxed to the water washing tower 25 from the circulation port at the top of the water washing tower 25, so as to control the mass concentration of ammonia in the solution within 5% under the premise of saving water, so as to facilitate the entry into the subsequent ammonia absorption tower 29 under the premise of ensuring qualified tail gas emissions; when it is necessary to replenish desalted water, the desalted water replenishment pump 23 and the eighth regulating valve 22 can be opened;

[0079] Step 7: When the solution in step 6 reaches a predetermined threshold, the seventh regulating valve 28 is opened to allow the solution in the fifth three-way valve 26 to enter the ammonia absorption tower 29 for use as an absorption liquid. The solution at the bottom of the ammonia absorption tower 29 is pressurized by the ammonia absorption tower bottom pump 33 and then refluxed from the circulation port at the upper part of the ammonia absorption tower 29 to the ammonia absorption tower 29 for recycling, so as to lay a foundation for entering the subsequent ammonium sulfate concentration oxidation tower 36 under the premise of the absorption liquid. When the absorption liquid needs to be supplemented and the solution in step 6 does not reach the predetermined threshold, the ammonia pump 35 is turned on to allow the ammonia tank 24 with the ammonia pipeline 57 to supplement ammonia as the absorption liquid into the ammonia absorption tower 29;

[0080] Step 8: When the solution in step 7 reaches a predetermined threshold, the sixth regulating valve 31 is opened to allow the ammonium sulfite solution in the fourth three-way valve 32 to enter the ammonium sulfate concentration oxidation tower 36 for oxidation crystallization. The hot air in the hot air pipe 55 takes away a portion of water vapor while oxidizing the ammonium sulfite, thereby concentrating the ammonium sulfate; the dirty nitrogen gas in the dirty nitrogen gas exhaust pipe 34 enters the ammonium sulfate concentration oxidation tower 36 to conduct secondary concentration of the ammonium sulfate; after the secondary concentration, the ammonium sulfate enters the crystallizer 37 for crystallization, and the mother liquor after crystallization enters the ammonia water tank 24 to be used as the absorption liquid of the ammonia water absorption tower 29;

[0081] Step 9: The solid phase crystallized by the crystallizer 37 in step 8 passes through the second weighing scale 38 and the second elevator 39 and enters the ammonium sulfate dissolving tank 45 inside the compound fertilizer granulation tower 40 to be used for preparing compound fertilizer;

[0082] Step 10: When it is necessary to prepare sulfur-nitrogen-potassium ternary compound fertilizer, open the first regulating valve 47, the second regulating valve 48, the third regulating valve 44 and the fifth regulating valve 46, and close the fourth regulating valve 42. The potassium chloride in the potassium chloride warehouse 52 enters the potassium chloride dissolving tank 43 through the first weighing scale 53 and the first elevator 54, and the urea solution in the urea solution storage tank 51 enters the potassium chloride dissolving tank 43 and the ammonium sulfate dissolving tank 45 respectively through the urea solution pump 50, so that the urea solution with a concentration of 99% dissolves the potassium chloride and ammonium sulfate respectively. After dissolution, the urea solution containing potassium chloride enters the ammonium sulfate dissolving tank 45 by utilizing the height difference for mixing to obtain compound fertilizer slurry; the compound fertilizer slurry enters the granulation nozzle 41 for granulation.

[0083] Example 3

[0084] A synthetic ammonia unit acid gas comprehensive utilization device comprises a gasification system acid gas unit, a low temperature methanol washing system acid gas unit and a shift stripping tower acid gas unit, wherein the gasification system acid gas unit is respectively connected to the tracing gas inlet of the Claus combustion furnace 18 and the tracing gas inlet of the waste gas combustion furnace 21 in the sulfur preparation unit; the low temperature methanol washing system acid gas unit is connected to the inlet of the Claus combustion furnace 18, and the shift stripping tower acid gas unit is connected to the inlet of the waste gas combustion furnace 21; the top tail gas outlet of the waste gas combustion furnace 21 is connected to the tail gas treatment unit, the tail gas treatment unit is coupled to the ammonium sulfite solution preparation unit, and the ammonium sulfite solution preparation unit is connected to the ammonium sulfate preparation unit. The tail gas treatment unit includes an ammonia absorption tower 29 connected to the tail gas outlet of the exhaust gas combustion furnace 21, the gas phase outlet at the top of the ammonia absorption tower 29 is connected to the inlet of the water washing tower 25, and the gas phase outlet at the top of the water washing tower 25 is connected to the atmosphere; the ammonium sulfite solution preparation unit includes a desalted water storage tank 30, the desalted water storage tank 30 is connected to the water washing tower 25 through a desalted water replenishment pump 23 and an eighth regulating valve 22, and the bottom outlet of the water washing tower 25 is connected to the circulation port at the top of the water washing tower 25 through a water washing tower bottom pump 27. A fifth tee 26 is provided between the washing tower bottom pump 27 and the circulation port at the top of the washing tower 25, and the third end of the fifth tee 26 is connected to the liquid inlet of the ammonia absorption tower 29 through the seventh regulating valve 28; the bottom outlet of the ammonia absorption tower 29 is connected to the circulation port at the top of the ammonia absorption tower 29 through the ammonia absorption tower bottom pump 33, and a fourth tee 32 is provided between the ammonia absorption tower bottom pump 33 and the circulation port at the top of the ammonia absorption tower 29, and the third end of the fourth tee 32 is connected to the ammonium sulfate concentration oxidation tower 36 through the sixth regulating valve 31. The ammonia absorption tower 29 is provided with an ammonia absorption tower replenishing port, and the ammonia absorption tower replenishing port is connected to the ammonia tank 24 with an ammonia pipeline 57 through the ammonia pump 35. The ammonium sulfate preparation unit includes an ammonium sulfate concentration oxidation tower 36, which is respectively connected to the dirty nitrogen gas exhaust pipe 34 and the hot air pipe 55 in the air separation system, the bottom outlet of the ammonium sulfate concentration oxidation tower 36 is connected to the crystallizer 37, the solid phase outlet of the crystallizer 37 is connected to the compound fertilizer production unit, and the liquid phase outlet of the crystallizer 37 is connected to the liquid replenishment port of the ammonia water tank 34; the top gas phase outlet of the ammonium sulfate concentration oxidation tower 36 is connected to the inlet of the water washing tower 25.The compound fertilizer production unit includes a compound fertilizer granulation tower 40, a urea solution storage tank 51, and a potassium chloride warehouse 52; the compound fertilizer granulation tower 40 includes a granulation nozzle 41 arranged at the middle and upper part of the compound fertilizer granulation tower 40, the inlet of the granulation nozzle 41 is connected to the outlets of the potassium chloride dissolving tank 43 and the ammonium sulfate dissolving tank 45 through the fourth regulating valve 42 and the fifth regulating valve 46 respectively, the solid phase inlet of the potassium chloride dissolving tank 43 is connected to the potassium chloride warehouse 52 through the first hoist 54 and the first weighing scale 53, and the solid phase inlet of the ammonium sulfate dissolving tank 45 is connected to the potassium chloride warehouse 52 through the second hoist 54 and the first weighing scale 53. The elevator 39 and the second weighing scale 38 are connected to the solid phase outlet of the crystallizer 37; the liquid phase outlets of the potassium chloride dissolving tank 43 and the ammonium sulfate dissolving tank 45 are respectively connected to the first three-way valve 49 through the corresponding first regulating valve 47 and the second regulating valve 48, and the third end of the first three-way valve 49 is connected to the outlet of the urea solution storage tank 51 through the urea solution pump 50; the setting height of the potassium chloride dissolving tank 43 is greater than the setting height of the ammonium sulfate dissolving tank 45, and the outlet of the potassium chloride dissolving tank 43 is connected to the inlet of the ammonium sulfate dissolving tank 45 through the third regulating valve 44. The gasification system acid gas unit comprises a gasification high temperature flash tank 1, the gas phase outlet at the top of the gasification high temperature flash tank 1 is connected to the gas phase inlet at the bottom of the gasification high temperature hot water tower 3, the upper part of the gasification high temperature hot water tower 3 is provided with a gasification low temperature ash water pipeline 2, the gas phase outlet at the top of the gasification high temperature hot water tower 3 is connected to the first acid gas cooler 5, the liquid phase outlet of the first acid gas cooler 5 is connected to the gasification clarification tank 6, and the gas phase outlet of the first acid gas cooler 5 is respectively connected to the heat gas inlet of the Claus combustion furnace 18 and the heat gas inlet of the exhaust gas combustion furnace 21 through the third three-way 16. A second three-way 11 and a tenth regulating valve 15 are arranged in sequence between the gas phase outlet of the first acid gas cooler 5 and the third three-way 16, and the third end of the second three-way 11 is connected to the conversion furnace 14 in the conversion system through the ninth regulating valve 12 and the fuel gas compressor 13; an eleventh regulating valve 17 is arranged between the third three-way 16 and the heat gas inlet of the Claus combustion furnace 18. The low temperature methanol washing system acid gas unit comprises a methanol washing heat regenerator 9, the gas phase outlet of the methanol washing heat regenerator 9 is connected to the acid gas liquid separator 15 through the second acid gas cooler 10, and the gas phase outlet of the acid gas liquid separator 15 is connected to the raw gas inlet of the Claus combustion furnace 18; the shift stripping tower acid gas unit comprises a low pressure flash tank 4, the gas phase outlet of the low pressure flash tank 4 is connected to the gas phase inlet of the lower part of the shift stripping tower 7, the upper inlet of the shift stripping tower 7 is connected to the shift ammonia washing tower waste liquid pipeline 8, and the gas phase outlet of the top of the shift stripping tower 7 is connected to the inlet of the waste gas combustion furnace 21. The sulfur preparation unit comprises a Claus combustion furnace 18, the outlet of the Claus combustion furnace 18 is connected to the inlet of the Claus reactor 19, the liquid phase outlet of the Claus reactor 19 is connected to the sulfur warehouse 20 through the sulfur granulation device 56, and the gas phase outlet of the Claus reactor 19 is connected to the inlet of the waste gas combustion furnace 21.

[0085] The present invention also provides a method for comprehensive utilization of acid gas from a synthetic ammonia device, the method comprising the following steps:

[0086] Step 1: The high-temperature black water in the gasification system enters the gasification high-temperature flash tank 1 for flash evaporation. The flashed gas phase enters the gasification high-temperature hot water tower 3 to transfer mass and heat with the gasification low-temperature ash water from the gasification low-temperature ash water pipeline 2. The non-condensable gas and part of the water vapor that are not absorbed enter the first acid gas cooler 5 for condensation. The condensed liquid phase enters the gasification clarification tank 6 for repeated use as gasification circulating water. The uncondensed acid gas enters the second three-way valve 11. One way is sent to the fuel gas compressor 13 through the ninth regulating valve 12 for pressurization. After the pressure is increased to 6.3 MPa (G), it is sent to the conversion furnace 14 in the conversion system as a raw material for recycling. The other way enters the third three-way valve 16 through the first regulating valve 15, and enters the exhaust gas combustion furnace 21 and the Claus combustion furnace 18 respectively for use as fuel gas.

[0087] Step 2: The low-pressure steam from the low-pressure flash tank 4 of the gasification system enters the conversion stripping tower 7 as the stripping heat source of the conversion stripping tower 7, and is countercurrently contacted with the conversion ammonia washing tower waste liquid from the conversion ammonia washing tower waste liquid pipeline 8, so as to strip out the acid gas in the conversion ammonia washing tower waste liquid, and the stripped acid gas enters the waste gas combustion furnace 21 for incineration treatment;

[0088] Step 3: The acid gas from the methanol heat washing regenerator 9 enters the second acid gas cooler 10 for condensation, and the methanol and water in the acid gas are condensed out. The condensed acid gas enters the acid gas separator 15 for separation, and the separated gas phase enters the Claus combustion furnace 18 for combustion;

[0089] Step 4: The acid gas in the above steps 1 and 3 enters the Claus combustion furnace 18 for combustion, partially converts hydrogen sulfate into sulfur dioxide, and then enters the Claus reactor 19 for hydrogen sulfide and sulfur dioxide to react to produce liquid sulfur, the liquid sulfur enters the sulfur granulation device 56 for granulation, and the granulated sulfur enters the sulfur warehouse 20 for packaging and sales; the tail gas produced in the Claus reactor 19 enters the exhaust gas combustion furnace 21 for incineration treatment; the tail gas produced in the above Claus reactor 19 contains some carbon monoxide and sulfur dioxide that are not fully reacted;

[0090] Step 5: The acid gas in the aforementioned step 1, the acid gas in step 2, and the tail gas produced in the Claus reactor 19 in step 4 enter the exhaust gas combustion furnace 21 for full combustion, and the tail gas of the exhaust gas combustion furnace 21 enters the ammonia absorption tower 29, and the sulfur dioxide in the tail gas is absorbed by the ammonia absorption tower 29. The tail gas after the ammonia absorption enters the water washing tower 25 for washing and then meets the emission standards;

[0091] Step 6: The desalted water in the desalted water storage tank 30 is pressurized by the desalted water replenishment pump 23 and sent to the water washing tower 25 to wash the tail gas after ammonia absorption, and the eighth regulating valve 22 is used to adjust the amount of desalted water entering the water washing tower 25; the solution at the bottom of the water washing tower 25 is pressurized by the water washing tower bottom pump 27 and then refluxed to the water washing tower 25 from the circulation port at the top of the water washing tower 25, so as to control the mass concentration of ammonia in the solution within 5% under the premise of saving water, so as to facilitate the entry into the subsequent ammonia absorption tower 29 under the premise of ensuring qualified tail gas emissions; when it is necessary to replenish desalted water, the desalted water replenishment pump 23 and the eighth regulating valve 22 can be opened;

[0092] Step 7: When the solution in step 6 reaches a predetermined threshold, the seventh regulating valve 28 is opened to allow the solution in the fifth three-way valve 26 to enter the ammonia absorption tower 29 for use as an absorption liquid. The solution at the bottom of the ammonia absorption tower 29 is pressurized by the ammonia absorption tower bottom pump 33 and then refluxed from the circulation port at the upper part of the ammonia absorption tower 29 to the ammonia absorption tower 29 for recycling, so as to lay a foundation for entering the subsequent ammonium sulfate concentration oxidation tower 36 under the premise of the absorption liquid. When the absorption liquid needs to be supplemented and the solution in step 6 does not reach the predetermined threshold, the ammonia pump 35 is turned on to allow the ammonia tank 24 with the ammonia pipeline 57 to supplement ammonia as the absorption liquid into the ammonia absorption tower 29;

[0093] Step 8: When the solution in step 7 reaches a predetermined threshold, the sixth regulating valve 31 is opened to allow the ammonium sulfite solution in the fourth three-way valve 32 to enter the ammonium sulfate concentration oxidation tower 36 for oxidation crystallization. The hot air in the hot air pipe 55 takes away a portion of water vapor while oxidizing the ammonium sulfite, thereby concentrating the ammonium sulfate; the dirty nitrogen gas in the dirty nitrogen gas exhaust pipe 34 enters the ammonium sulfate concentration oxidation tower 36 to conduct secondary concentration of the ammonium sulfate; after the secondary concentration, the ammonium sulfate enters the crystallizer 37 for crystallization, and the mother liquor after crystallization enters the ammonia water tank 24 to be used as the absorption liquid of the ammonia water absorption tower 29;

[0094] Step 9: When it is necessary to prepare nitrogen-potassium binary compound fertilizer, the solid phase crystallized by the crystallizer 37 in step 8 is dried and then sold; the second regulating valve 48, the third regulating valve 44 and the fifth regulating valve 46 are closed, the first regulating valve 47 and the fourth regulating valve 42 are opened, and the urea solution in the urea solution storage tank 51 enters the potassium chloride dissolving tank 43 through the urea solution pump 50, so that the urea solution with a concentration of 99% dissolves the potassium chloride, and after dissolution, it enters the granulation nozzle 41 for granulation.

[0095] It should be noted that, in this article, the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0096] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. The above are only preferred implementation methods of the present invention. It should be pointed out that due to the limitations of textual expression, there are objectively infinite specific structures. For ordinary technicians in this technical field, without departing from the principles of the present invention, several improvements, modifications or changes can be made, and the above technical features can be combined in an appropriate manner; these improvements, changes or combinations, or the direct application of the inventive concept and technical solution to other occasions without improvement, should be regarded as the protection scope of the present invention.

Claims

1. A comprehensive utilization device for acid gas from a synthetic ammonia plant, characterized by: Including gasification system acid gas unit, low temperature methanol washing system acid gas unit and conversion stripping tower acid gas unit, The acid gas unit of the gasification system is respectively connected to the heat-tracing gas inlet of the Claus combustion furnace (18) and the heat-tracing gas inlet of the exhaust gas combustion furnace (21) in the sulfur preparation unit; The low temperature methanol washing system acid gas unit is connected to the inlet of the Claus combustion furnace (18), and the conversion stripping tower acid gas unit is connected to the inlet of the exhaust gas combustion furnace (21); The tail gas outlet at the top of the waste gas combustion furnace (21) is connected to the tail gas treatment unit, the tail gas treatment unit is coupled to the ammonium sulfite solution preparation unit, and the ammonium sulfite solution preparation unit is connected to the ammonium sulfate preparation unit.

2. The device for comprehensive utilization of acid gas from a synthetic ammonia plant according to claim 1, characterized in that: The tail gas treatment unit comprises an ammonia absorption tower (29) connected to the tail gas outlet of the exhaust gas combustion furnace (21), the gas phase outlet at the top of the ammonia absorption tower (29) is connected to the inlet of the water washing tower (25), and the gas phase outlet at the top of the water washing tower (25) is connected to the atmosphere; The ammonium sulfite solution preparation unit comprises a desalted water storage tank (30), the desalted water storage tank (30) is connected to a water washing tower (25) via a desalted water replenishment pump (23) and an eighth regulating valve (22), the bottom outlet of the water washing tower (25) is connected to a circulation port at the top of the water washing tower (25) via a water washing tower bottom pump (27), a fifth three-way valve (26) is arranged between the water washing tower bottom pump (27) and the circulation port at the top of the water washing tower (25), and the third of the fifth three-way valve (26) is connected to the circulation port at the top of the water washing tower (25). The end is connected to the liquid inlet of the ammonia absorption tower (29) through a seventh regulating valve (28); the bottom outlet of the ammonia absorption tower (29) is connected to the circulation port at the top of the ammonia absorption tower (29) through an ammonia absorption tower bottom pump (33); a fourth tee (32) is provided between the ammonia absorption tower bottom pump (33) and the circulation port at the top of the ammonia absorption tower (29); the third end of the fourth tee (32) is connected to the ammonium sulfate concentration oxidation tower (36) through a sixth regulating valve (31).

3. The device for comprehensive utilization of acid gas from a synthetic ammonia plant according to claim 2, characterized in that: The ammonia absorption tower (29) is provided with an ammonia absorption tower replenishing port, which is connected to an ammonia tank (24) with an ammonia pipeline (57) via an ammonia pump (35).

4. The device for comprehensive utilization of acid gas from a synthetic ammonia plant according to claim 3, characterized in that: The ammonium sulfate preparation unit comprises an ammonium sulfate concentration oxidation tower (36), which is respectively connected to a dirty nitrogen gas exhaust pipe (34) and a hot air pipe (55) in an air separation system; a bottom outlet of the ammonium sulfate concentration oxidation tower (36) is connected to a crystallizer (37); a solid phase outlet of the crystallizer (37) is connected to a compound fertilizer production unit; a liquid phase outlet of the crystallizer (37) is connected to a liquid replenishment port of an ammonia water tank (34); and a top gas phase outlet of the ammonium sulfate concentration oxidation tower (36) is connected to an inlet of a water washing tower (25).

5. The device for comprehensive utilization of acid gas from a synthetic ammonia plant according to claim 4, characterized in that: The compound fertilizer production unit comprises a compound fertilizer granulation tower (40), a urea solution storage tank (51), and a potassium chloride warehouse (52); The compound fertilizer granulation tower (40) comprises a granulation nozzle (41) arranged at the middle and upper part of the compound fertilizer granulation tower (40); the inlet of the granulation nozzle (41) is connected to the outlets of the potassium chloride dissolving tank (43) and the ammonium sulfate dissolving tank (45) through a fourth regulating valve (42) and a fifth regulating valve (46) respectively; the solid phase inlet of the potassium chloride dissolving tank (43) is connected to the potassium chloride warehouse (52) through a first elevator (54) and a first weighing scale (53); the solid phase inlet of the ammonium sulfate dissolving tank (45) is connected to the solid phase outlet of the crystallizer (37) through a second elevator (39) and a second weighing scale (38); the liquid phase outlets of the potassium chloride dissolving tank (43) and the ammonium sulfate dissolving tank (45) are connected to the first tee (49) through the first regulating valve (47) and the second regulating valve (48) respectively; the third end of the first tee (49) is connected to the outlet of the urea solution storage tank (51) through a urea solution pump (50); The potassium chloride dissolving tank (43) is arranged at a height greater than that of the ammonium sulfate dissolving tank (45), and the outlet of the potassium chloride dissolving tank (43) is connected to the inlet of the ammonium sulfate dissolving tank (45) via a third regulating valve (44).

6. The device for comprehensive utilization of acid gas from a synthetic ammonia plant according to claim 1, characterized in that: The gasification system acid gas unit comprises a gasification high temperature flash tank (1), the gas phase outlet at the top of the gasification high temperature flash tank (1) is connected to the gas phase inlet at the bottom of the gasification high temperature hot water tower (3), the upper part of the gasification high temperature hot water tower (3) is provided with a gasification low temperature ash water pipeline (2) connected, the gas phase outlet at the top of the gasification high temperature hot water tower (3) is connected to the first acid gas cooler (5), the liquid phase outlet of the first acid gas cooler (5) is connected to the gasification clarification tank (6), and the gas phase outlet of the first acid gas cooler (5) is respectively connected to the heat gas inlet of the Claus combustion furnace (18) and the heat gas inlet of the exhaust gas combustion furnace (21) through a third tee (16).

7. The device for comprehensive utilization of acid gas from a synthetic ammonia plant according to claim 6, characterized in that: A second three-way valve (11) and a tenth regulating valve (15) are provided in sequence between the gas phase outlet of the first acid gas cooler (5) and the third three-way valve (16); a third end of the second three-way valve (11) is connected to a conversion furnace (14) in the conversion system through a ninth regulating valve (12) and a fuel gas compressor (13); An eleventh regulating valve (17) is provided between the third three-way valve (16) and the combustion gas inlet of the Claus combustion furnace (18).

8. The device for comprehensive utilization of acid gas from a synthetic ammonia plant according to claim 1, characterized in that: The low-temperature methanol washing system acid gas unit comprises a methanol washing heat regenerator (9), the gas phase outlet of the methanol washing heat regenerator (9) is connected to the acid gas liquid separator tank (15) through a second acid gas cooler (10), and the gas phase outlet of the acid gas liquid separator tank (15) is connected to the raw gas inlet of the Claus combustion furnace (18); The conversion stripping tower acid gas unit comprises a low-pressure flash tank (4), the gas phase outlet of the low-pressure flash tank (4) is connected to the gas phase inlet at the bottom of the conversion stripping tower (7), the upper inlet of the conversion stripping tower (7) is connected to the conversion ammonia washing tower waste liquid pipeline (8), and the gas phase outlet at the top of the conversion stripping tower (7) is connected to the inlet of the waste gas combustion furnace (21).

9. The device for comprehensive utilization of acid gas from a synthetic ammonia plant according to claim 1, characterized in that: The sulfur preparation unit comprises a Claus combustion furnace (18), the outlet of the Claus combustion furnace (18) is connected to the inlet of a Claus reactor (19), the liquid phase outlet of the Claus reactor (19) is connected to a sulfur warehouse (20) through a sulfur granulation device (56), and the gas phase outlet of the Claus reactor (19) is connected to the inlet of a waste gas combustion furnace (21).

10. A method for comprehensive utilization of acid gas from a synthetic ammonia plant, characterized by: The comprehensive utilization method comprises the following steps: Step 1: High-temperature black water in the gasification system enters the gasification high-temperature flash tank (1) for flash evaporation. The gas phase after flash evaporation enters the gasification high-temperature hot water tower (3) to transfer mass and heat with the gasification low-temperature ash water from the gasification low-temperature ash water pipeline (2). The non-condensable gas and part of the water vapor that are not absorbed enter the first acid gas cooler (5) for condensation. The condensed liquid phase enters the gasification clarification tank (6) for reuse as gasification circulating water. The acid gas that is not condensed enters the second tee (11). One path is sent to the fuel gas compressor (13) through the ninth regulating valve (12) for pressurization. After the pressure is increased to 6.3 MPa (G), it is sent to the conversion furnace (14) in the conversion system as raw material for recycling. The other path enters the third tee (16) through the first regulating valve (15) and enters the waste gas combustion furnace (21) and the Claus combustion furnace (18) respectively for use as fuel gas. Step 2: The low-pressure steam in the low-pressure flash tank (4) of the gasification system enters the conversion stripping tower (7) as a stripping heat source of the conversion stripping tower (7), and is countercurrently contacted with the conversion ammonia washing tower waste liquid from the conversion ammonia washing tower waste liquid pipeline (8), so as to strip out the acid gas in the conversion ammonia washing tower waste liquid, and the stripped acid gas enters the waste gas combustion furnace (21) for incineration treatment; Step 3: The acid gas from the methanol heat washing regenerator (9) enters the second acid gas cooler (10) for condensation, and the methanol and water in the acid gas are condensed out. The condensed acid gas enters the acid gas separator (15) for separation, and the separated gas phase enters the Claus combustion furnace (18) for combustion; Step 4: The acid gas in the above steps 1 and 3 enters the Claus combustion furnace (18) for combustion, converts the hydrogen sulfate into sulfur dioxide, and then enters the Claus reactor (19) for hydrogen sulfide and sulfur dioxide to react to produce liquid sulfur. The liquid sulfur enters the sulfur granulation device (56) for granulation. The granulated sulfur enters the sulfur warehouse (20) for packaging and sales. The tail gas produced in the Claus reactor (19) enters the waste gas combustion furnace (21) for incineration treatment; the tail gas produced in the Claus reactor (19) contains some carbon monoxide and sulfur dioxide that have not been fully reacted; Step 5: The acid gas in the above-mentioned step 1, the acid gas in step 2 and the tail gas produced in the Claus reactor (19) in step 4 enter the exhaust gas combustion furnace (21) for full combustion, and the tail gas of the exhaust gas combustion furnace (21) enters the ammonia absorption tower (29), and the sulfur dioxide in the tail gas is absorbed by ammonia. The tail gas is absorbed by ammonia in the ammonia absorption tower (29), and the tail gas after ammonia absorption enters the water washing tower (25) for washing and then meets the emission standards; Step 6: The desalted water in the desalted water storage tank (30) is pressurized by the desalted water replenishment pump (23) and then sent to the water washing tower (25) to wash the tail gas after ammonia absorption, and the eighth regulating valve (22) is used to adjust the amount of desalted water entering the water washing tower (25); the solution at the bottom of the water washing tower (25) is pressurized by the water washing tower bottom pump (27) and then refluxed to the water washing tower (25) from the circulation port at the top of the water washing tower (25), so as to control the mass concentration of ammonia in the solution within 5% under the premise of saving water, so as to facilitate the entry into the subsequent ammonia absorption tower (29) under the premise of ensuring qualified tail gas emissions; when it is necessary to replenish desalted water, the desalted water replenishment pump (23) and the eighth regulating valve (22) can be opened; Step 7: When the solution in step 6 reaches a predetermined threshold, the seventh regulating valve (28) is opened to allow the solution in the fifth three-way valve (26) to enter the ammonia absorption tower (29) for use as an absorption liquid. The solution at the bottom of the ammonia absorption tower (29) is pressurized by the ammonia absorption tower bottom pump (33) and then refluxed from the circulation port at the top of the ammonia absorption tower (29) to the ammonia absorption tower (29) for recycling, so as to lay a foundation for entering the subsequent ammonium sulfate concentration oxidation tower (36) under the premise of absorption liquid. When the absorption liquid needs to be supplemented and the solution in step 6 does not reach the predetermined threshold, the ammonia pump (35) is turned on to allow the ammonia tank (24) with the ammonia pipeline (57) to supplement ammonia as absorption liquid into the ammonia absorption tower (29); Step 8: When the solution in step 7 reaches a predetermined threshold, the sixth regulating valve (31) is opened to allow the ammonium sulfite solution in the fourth three-way (32) to enter the ammonium sulfate concentration oxidation tower (36) for oxidation crystallization. The hot air in the hot air pipe (55) takes away a portion of water vapor while oxidizing the ammonium sulfite, thereby concentrating the ammonium sulfate. The contaminated nitrogen gas in the contaminated nitrogen gas exhaust pipe (34) enters the ammonium sulfate concentration oxidation tower 36 to perform secondary concentration of the ammonium sulfate. After the secondary concentration, the ammonium sulfate enters the crystallizer (37) for crystallization, and the mother liquor after crystallization enters the ammonia water tank (24) for use as the absorption liquid of the ammonia water absorption tower (29). Step 9: The solid phase crystallized by the crystallizer (37) in step 8 enters the ammonium sulfate dissolving tank (45) inside the compound fertilizer granulation tower (40) through the second weighing scale (38) and the second elevator (39) and can be used to prepare compound fertilizer; Step 10: When it is necessary to prepare sulfur-nitrogen binary compound fertilizer, the first regulating valve (47), the fourth regulating valve (42) and the third regulating valve (44) are closed, and the second regulating valve (48) and the fifth regulating valve (46) are opened. The urea solution in the urea solution storage tank (51) enters the ammonium sulfate dissolving tank (45) through the urea solution pump (50), so that the urea solution with a concentration of 99% dissolves the ammonium sulfate. After the ammonium sulfate is dissolved, the urea solution enters the granulation nozzle (41) for granulation. Step 11: When it is necessary to prepare sulfur-nitrogen-potassium ternary compound fertilizer, the first regulating valve (47), the second regulating valve (48), the third regulating valve (44) and the fifth regulating valve (46) are opened, and the fourth regulating valve (42) is closed. The potassium chloride in the potassium chloride warehouse (52) enters the potassium chloride dissolving tank (43) through the first weighing scale (53) and the first elevator (54), and the urea solution in the urea solution storage tank (51) enters the potassium chloride dissolving tank (43) and the ammonium sulfate dissolving tank (45) respectively through the urea solution pump (50), so that the urea solution with a concentration of 99% dissolves the potassium chloride and the ammonium sulfate respectively. After the dissolution, the urea solution containing potassium chloride enters the ammonium sulfate dissolving tank (45) by utilizing the height difference for mixing to obtain compound fertilizer slurry; the compound fertilizer slurry enters the granulation nozzle (41) for granulation; Step 12: When it is necessary to prepare nitrogen-potassium binary compound fertilizer, the solid phase crystallized by the crystallizer (37) in step 8 is dried and then sold; the second regulating valve (48), the third regulating valve (44) and the fifth regulating valve (46) are closed, the first regulating valve (47) and the fourth regulating valve (42) are opened, and the urea solution in the urea solution storage tank (51) enters the potassium chloride dissolving tank (43) through the urea solution pump (50), so that the urea solution with a concentration of 99% dissolves the potassium chloride, and after dissolution, the potassium chloride enters the granulation nozzle (41) for granulation.

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