Comprehensive treatment device and treatment process for waste gas of ammonia synthesis system

Abstract

The invention relates to a comprehensive treatment device and process for waste gas of a synthetic ammonia system. Comprising a shift stripping tail gas unit, a sulfur-containing tail gas pipeline of a low-temperature methanol washing device, a low-pressure oxygen pipeline of an air separation device and a fuel gas storage tank, a sulfur-containing tail gas pipeline of the low-temperature methanol washing device, a low-pressure oxygen pipeline of the air separation device and the fuel gas storage tank are respectively connected with an inlet of the combustion furnace, and an outlet of the combustion furnace is connected with the first gas-liquid separator through the sulfur recovery unit; a gas phase outlet of the first gas-liquid separator, the conversion steam stripping tail gas unit, the fuel gas storage tank and the air pipeline are respectively connected with an inlet of the incinerator, an outlet of the incinerator is connected with the boiler through the heat exchange unit, and a flue gas outlet of the boiler is connected with the chimney through the denitration device and the desulfurization device; the waste gas in the ammonia synthesis system can be uniformly treated according to properties, desulfurization and denitration devices are not independently arranged, and linkage design of tail gas treatment of the whole system is realized, so that the advantages of investment saving and environment friendliness are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of synthetic ammonia systems, and in particular to a synthetic ammonia system waste gas comprehensive treatment device and a treatment process. Background Art

[0002] In the synthetic ammonia system, multiple tail gases are generated, such as tail gas from the conversion stripping tower, tail gas from the low-temperature methanol washing device, etc. According to the conventional industry settings, multiple corresponding tail gas treatment devices are designed according to the composition, characteristics and flow rate of different tail gases; that is, a set of synthetic ammonia system will be equipped with multiple combustion torches, desulfurization equipment, etc., which not only occupies a large area, requires large equipment investment and is not easy to operate; further, for the stripping tail gas produced by the conversion device, it is usually sent to the flare for combustion or to the sulfur recovery combustion for treatment; taking the flare combustion as an example, the flare combustion method not only wastes resources, but also has the risk of polluting the environment; taking the sulfur recovery combustion as an example, since the tail gas contains ammonia, the ammonia The combustion stability is higher than that of hydrogen sulfide. To process this tail gas with a small flow rate, the design specifications of the sulfur recovery furnace need to be improved, resulting in a substantial increase in sulfur recovery investment. In addition, when sulfur recovery adopts the sulfur production process, it is insufficiently burned due to lack of oxygen. The tail gas composition after combustion is 1.25 hydrogen, 10.9 nitrogen, 3.1 carbon monoxide, 45.3 carbon dioxide, 0.28 hydrogen sulfide, 0.14 sulfur dioxide, and 39.03 water (molar fraction). Since the tail gas contains carbon monoxide and hydrogen, and its content exceeds 10% of its explosion limit, if it is directly sent to the boiler for combustion, it will lead to an increase in the explosion zone division of the boiler area, resulting in an increase in the investment in the boiler device, and needs to be handled separately. Summary of the invention

[0003] The object of the present invention is to provide a comprehensive waste gas treatment device and treatment process for a synthetic ammonia system to overcome the defects in the prior art.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A comprehensive waste gas treatment device for a synthetic ammonia system comprises a shift stripping tail gas unit, a sulfur-containing tail gas pipeline of a low-temperature methanol washing device, a low-pressure oxygen pipeline of an air separation device and a fuel gas storage tank; the sulfur-containing tail gas pipeline of the low-temperature methanol washing device, the low-pressure oxygen pipeline of the air separation device and the fuel gas storage tank are respectively connected to the inlet of a combustion furnace, and the outlet of the combustion furnace is connected to a first gas-liquid separator through a sulfur recovery unit; the gas phase outlet of the first gas-liquid separator, the shift stripping tail gas unit, the fuel gas storage tank and the air pipeline are respectively connected to the inlet of an incinerator, the outlet of the incinerator is connected to a boiler through a heat exchange unit, and the flue gas outlet of the boiler is connected to a chimney through a denitration device and a desulfurization device.

[0006] The beneficial effects of the present invention are as follows: a combustion furnace is set up to burn the sulfur-containing tail gas from the low-temperature methanol washing device and the low-pressure oxygen in the air separation device, so as to achieve the purpose of sulfur recovery in the subsequent process, and then the sulfur recovered gas phase and the fuel gas, the conversion stripping tail gas, etc. enter the incinerator for incineration, and the heat is recovered after incineration. The tail gas is treated by the denitration device and the desulfurization device matched in the boiler, so as to reduce the difficulty of waste gas treatment in the synthetic ammonia system, and realize the characteristics of a set of desulfurization and denitration devices to treat the waste gas of the entire synthetic ammonia system while recovering sulfur from the tail gas.

[0007] Preferably, the sulfur recovery unit includes a first steam generator, the outlet of the combustion furnace is connected to the first heat exchange channel of the first steam generator, the liquid phase outlet of the first heat exchange channel is connected to the liquid sulfur pool, the gas phase outlet of the first heat exchange channel is connected to a plurality of sulfur recovery components arranged in series, the gas phase outlet of the terminal sulfur recovery component is connected to the first gas-liquid separator, and the liquid phase outlet of the first liquid separator is connected to the liquid sulfur pool.

[0008] Preferably, the sulfur recovery component includes a steam heater and a sulfur reactor, the first heat exchange channel inlet of the steam heater is connected to the first heat exchange channel outlet of the first steam generator or the first heat exchange channel outlet of the previous sulfur reactor, the first heat exchange channel outlet of the steam heater is connected to the inlet of the corresponding sulfur reactor, the material outlet of the sulfur reactor is connected to the liquid sulfur pool through the corresponding sulfur condenser, and the gas phase outlet of the sulfur reactor is connected to the first heat exchange channel inlet of the next steam heater or the inlet of the first gas-liquid separator.

[0009] Preferably, the inlet of the second heat exchange channel of the first steam generator is connected to the low-pressure boiler feed water pipeline, and the outlet of the second heat exchange channel of the first steam generator is connected to the 0.5 MPa steam network.

[0010] Preferably, the second channel inlet of the steam heater is connected to the 4MPa steam network, and the second channel outlet of the steam heater is connected to the condensate recovery tank.

[0011] Preferably, the heat exchange unit includes a steam superheater, the outlet of the incinerator is connected to the first pipe of the second steam generator through the first pipe of the steam superheater, the first pipe of the second steam generator is connected to the boiler inlet through the first channel of the fresh air heat exchanger; the air duct is connected to the inlet of the incinerator through the blower and the second channel of the fresh air heat exchanger.

[0012] Preferably, the second pipe inlet of the second steam generator is connected to the low-pressure boiler feed water pipe, the second pipe outlet of the second steam generator is connected to the second pipe inlet of the steam superheater, and the second pipe outlet of the steam superheater is connected to the 0.6MPa superheated steam pipeline network.

[0013] Preferably, the conversion stripping tail gas unit includes a conversion ammonia washing tower, the liquid phase outlet of the conversion ammonia washing tower is connected to the conversion stripping tower through the first channel of the first condenser, the gas phase outlet of the conversion stripping tower is connected to the second channel of the first condenser and the first channel of the second condenser and the second gas-liquid separator, and the gas phase outlet of the second gas-liquid separator is connected to the incinerator.

[0014] Preferably, the liquid phase outlet of the second gas-liquid separator is connected to the gasification coal grinding device; the second channel inlet of the second condenser is connected to the circulating water supply pipeline, and the second channel outlet of the second condenser is connected to the circulating water return pipeline.

[0015] A treatment process using a comprehensive waste gas treatment device of a synthetic ammonia system, the process comprising the following steps:

[0016] Step 1: The sulfur-containing tail gas in the sulfur-containing tail gas pipeline of the low-temperature methanol washing device, the oxygen in the low-pressure oxygen pipeline of the air separation device, and the fuel gas in the fuel gas storage tank enter the combustion furnace for combustion, and the flow rate of oxygen entering the combustion furnace is controlled by the corresponding valve on the low-pressure oxygen pipeline, thereby controlling the molar ratio of hydrogen sulfide to sulfur dioxide in the tail gas after combustion in the combustion furnace to be lower than 2:1, so as to achieve complete conversion of all hydrogen sulfide gas, and the excess sulfur dioxide is removed by the subsequent desulfurization device;

[0017] Step 2: The exhaust gas after combustion in the combustion furnace has the following components: 1.35 hydrogen, 11.7 nitrogen, 3.3 carbon monoxide, 47.12 carbon dioxide, 6.92 hydrogen sulfide, 1.69 carbon oxysulfide, 4.33 sulfur dioxide, and 23.59 water; the exhaust gas after combustion enters the first heat exchange channel of the first steam generator to exchange heat with the desalted water from the low-pressure boiler feed water pipeline, and the steam in the second heat exchange channel of the first steam generator after heat exchange enters the 0.5MPa steam network, and the exhaust gas after heat exchange enters the first heat exchange channel of the steam heater for heating; the exhaust gas temperature after heat exchange is 170-180°C, and the exhaust gas heated by the steam heater is 240-250°C;

[0018] Step 3: the tail gas heated by the steam heater enters the corresponding sulfur reactor for reaction, the liquid phase after the reaction enters the corresponding sulfur condenser for condensation, and is sent to the liquid sulfur pool for recovery after condensation; the tail gas after the reaction in the sulfur reactor enters the first heat exchange path of the next steam heater for heating; the tail gas entering the first heat exchange path of the next steam heater has the following composition: 1.39 hydrogen, 12.12 nitrogen, 3.46 carbon monoxide, 50.55 carbon dioxide, 2.53 hydrogen sulfide, 0.02 carbon oxysulfide, 1.27 sulfur dioxide, and 28.66 water;

[0019] Step 4: the tail gas enters the first heat exchange passage of the next steam heater for heating, and after the tail gas is heated to 205-215° C., it is sent to the corresponding sulfur reactor for reaction, and the liquid phase after the reaction enters the corresponding sulfur condenser for condensation, and after condensation, it is sent to the liquid sulfur pool for recovery; the tail gas after the reaction in the sulfur reactor enters the first heat exchange passage of the next steam heater for heating; the tail gas entering the first heat exchange passage of the next steam heater has the following composition: 1.43 hydrogen, 12.38 nitrogen, 3.54 carbon monoxide, 51.67 carbon dioxide, 0.58 hydrogen sulfide, 0.02 carbon oxysulfide, 0.29 sulfur dioxide, and 30.09 water;

[0020] Step 5: the tail gas enters the first heat exchange passage of the next steam heater for heating, and after the tail gas is heated to 200-210° C., it is sent to the corresponding sulfur reactor for reaction, and the liquid phase after the reaction enters the corresponding sulfur condenser for condensation, and after condensation, it is sent to the liquid sulfur pool for recovery; the tail gas after the reaction in the sulfur reactor enters the first gas-liquid separator for gas-liquid separation, the liquid phase separated from the gas and liquid enters the liquid sulfur pool for recovery, and the gas phase separated from the gas and liquid enters the incinerator; the tail gas entering the first gas-liquid separator has the following composition: 1.43 hydrogen, 12.46 nitrogen, 3.56 carbon monoxide, 51.99 carbon dioxide, 0.24 hydrogen sulfide, 0.01 carbon oxysulfide, 0.12 sulfur dioxide, and 30.19 water;

[0021] Step 6: The ammonia-containing waste liquid in the conversion ammonia scrubber enters the conversion stripping tower through the first channel of the first condenser, and the conversion stripping tower strips out the ammonia and non-condensable gas in the waste liquid. The gas phase passes through the gas phase outlet of the conversion stripping tower, the second channel of the first condenser, and the first channel of the second condenser in sequence to enter the second gas-liquid separator for gas-liquid separation. The liquid phase after gas-liquid separation enters the gasification coal grinding device, and the gas phase after gas-liquid separation enters the incinerator;

[0022] Step 7: The air in the air duct enters the incinerator through the blower and the second channel of the fresh air heat exchanger;

[0023] Step 8: The fuel gas in the fuel gas storage tank, the gas phase of the first gas-liquid separator in step 5, the gas phase of the second gas-liquid separator in step 6, and the air passing through the second channel of the fresh air heat exchanger in step 7 enter the incinerator together for combustion. The gas composition after incineration in the incinerator is: 34.3% carbon dioxide, 41.9% nitrogen, 17.7% water, 1.1% sulfur dioxide, 5% oxygen, and 200mg / Nm3 of nitrogen oxides, and no longer contains combustible gas;

[0024] Step 9: The gas incinerated in the incinerator passes through the first pipeline of the steam superheater, the first pipeline of the second steam generator and the first channel of the fresh air heat exchanger for heat exchange; the gas after heat exchange enters the boiler, and then passes through the denitrification device to remove nitrogen oxides in the tail gas, and then passes through the desulfurization device to remove sulfur dioxide in the tail gas, and finally the qualified tail gas is discharged through the chimney;

[0025] The desalted water in the low-pressure boiler feed water pipe enters the second pipe of the second steam generator for heat exchange and then enters the second pipe of the steam superheater for further heat exchange. The produced steam enters the 0.6MPa superheated steam network.

[0026] According to the above scheme, a comprehensive waste gas treatment device and treatment process of a synthetic ammonia system are prepared. The essence of the present invention is to uniformly treat the waste gas in the synthetic ammonia system according to relevant properties, avoid designing a tail gas treatment device for each process separately, resulting in increased equipment investment, and due to the large number of tail gas treatment devices, there is an increase in the rate of non-compliant emissions, which poses a hidden danger to the environmental protection of the enterprise; the present invention not only realizes the recovery and utilization of heat and reduces the requirements for combustion equipment by sending the sulfur-containing tail gas from the low-temperature methanol washing device and the low-pressure oxygen and fuel gas in the air separation device into the combustion furnace for combustion, but also facilitates the effective recovery of sulfur; further, the tail gas after sulfur recovery and the fuel gas, the conversion stripping tail gas, etc. enter the incinerator for incineration, and the denitration and desulfurization system of the boiler device is used to treat the nitrogen oxides and sulfides in the tail gas, and no longer separately set up a desulfurization and denitration device with higher investment, so as to realize the linkage design of the tail gas treatment of the whole system, thereby achieving the advantages of saving investment, realizing effective utilization of thermal energy and environmental friendliness. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the present invention.

[0028] In the figure: 1. Sulfur-containing tail gas pipeline; 2. Low-pressure oxygen pipeline; 3. Fuel gas storage tank; 4. Combustion furnace; 5. First gas-liquid separator; 6. Air pipeline; 7. Incinerator; 8. Boiler; 9. Denitrification device; 10. Desulfurization device; 11. Chimney; 12. First steam generator; 13. Liquid sulfur pool; 14. Steam heater; 15. Sulfur reactor; 16. Sulfur condenser; 17. Low-pressure boiler feed water pipeline; 18. 0.5MPa steam network ; 19. 4MPa steam network; 20. Condensate recovery storage tank; 21. Steam superheater; 22. Second steam generator; 23 Fresh air heat exchanger; 24. Blower; 25. 0.6MPa superheated steam network; 26. Conversion ammonia washing tower; 27. First condenser; 28. Conversion stripping tower; 29. ​​Second condenser; 30. Second gas-liquid separator; 31. Gasification coal grinding device; 32. Circulating water supply pipeline; 33. Circulating return water pipeline. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0030] Reference Figure 1 As shown, the present invention is a comprehensive treatment device for waste gas from a synthetic ammonia system and a treatment process, wherein the device comprises a conversion stripping tail gas unit, a sulfur-containing tail gas pipeline 1 of a low-temperature methanol washing device, a low-pressure oxygen pipeline 2 and a fuel gas storage tank 3 of an air separation device; the sulfur-containing tail gas pipeline 1 of the low-temperature methanol washing device, the low-pressure oxygen pipeline 2 and the fuel gas storage tank 3 of the air separation device are respectively connected to the inlet of a combustion furnace 4, and the outlet of the combustion furnace 4 is connected to a first gas-liquid separator 5 through a sulfur recovery unit; the gas phase outlet of the first gas-liquid separator 5, the conversion stripping tail gas unit, the fuel gas storage tank 3 and the air pipeline 6 are respectively connected to the inlet of an incinerator 7, and the outlet of the incinerator 7 is connected to a boiler 8 through a heat exchange unit, and the flue gas outlet of the boiler 8 is connected to a chimney 11 through a denitration device 9 and a desulfurization device 10. The present invention can perform graded treatment on the waste gas according to the waste gas properties of the synthetic ammonia system, and effectively recover the heat of the waste gas combustion and the sulfur contained in the waste gas. On the premise of uniformly treating the waste gas, the waste gas is uniformly treated through the denitration device 9 and the desulfurization device 10 in the boiler system, and environmental friendliness is achieved by meeting the emission standards. The above-mentioned arrangement can achieve the purpose of reducing investment and construction costs and achieving easy operation.

[0031] Further, the sulfur recovery unit includes a first steam generator 12, the outlet of the combustion furnace 4 is connected to the first heat exchange channel of the first steam generator 12, the liquid phase outlet of the first heat exchange channel is connected to the liquid sulfur pool 13, the gas phase outlet of the first heat exchange channel is connected to a plurality of sulfur recovery components arranged in series, the gas phase outlet of the terminal sulfur recovery component is connected to the first gas-liquid separator 5, and the liquid phase outlet of the first liquid separator 5 is connected to the liquid sulfur pool 13. In the present invention, the heat in the tail gas can be recovered by setting the first steam generator 12, the sulfur element in the tail gas can be recovered by setting a plurality of sulfur recovery components arranged in series, and further, the sulfur element can be further recovered by setting the first gas-liquid separator 5, which can not only improve the emergency benefit, but also reduce the subsequent tail gas processing load (the processing load refers to the processing load of the incinerator 7 and the processing load of the desulfurization device 10).

[0032] Further, the sulfur recovery unit includes a steam heater 14 and a sulfur reactor 15, the first heat exchange channel inlet of the steam heater 14 is connected to the first heat exchange channel outlet of the first steam generator 12 or the first heat exchange channel outlet of the previous sulfur reactor 15, the first heat exchange channel outlet of the steam heater 14 is connected to the inlet of the corresponding sulfur reactor 15, the material outlet of the sulfur reactor 15 is connected to the liquid sulfur pool 13 through the corresponding sulfur condenser 16, and the gas phase outlet of the sulfur reactor 15 is connected to the first heat exchange channel inlet of the next steam heater 14 or the inlet of the first gas-liquid separator 5. It should be clear that the sulfur recovery unit described in the present invention is multiple (it can be set to two sets of sulfur recovery units, three sets of sulfur recovery units or four sets of sulfur recovery, etc. according to actual conditions), and its series design can realize step-by-step recovery of sulfur at different temperatures, so as to improve the sulfur recovery efficiency, reduce the subsequent load, and achieve the purpose of smooth operation of the system.

[0033] Furthermore, the inlet of the second heat exchange channel of the first steam generator 12 is connected to the low-pressure boiler feed water pipeline 17, and the outlet of the second heat exchange channel of the first steam generator 12 is connected to the 0.5MPa steam network 18. The present invention exchanges heat with the desalted water in the first steam generator 12 through the tail gas from the combustion furnace 4, and utilizes the heat energy of the tail gas to achieve the purpose of by-producing 0.5MPa steam.

[0034] Furthermore, the second channel inlet of the steam heater 14 is connected to the 4MPa steam pipe network 19, and the second channel outlet of the steam heater 14 is connected to the condensate recovery tank 20. The heat source in the steam heater 14 of the present invention is to heat the tail gas, thereby achieving the characteristic of sulfur recovery.

[0035] Furthermore, the heat exchange unit includes a steam superheater 21, the outlet of the incinerator 7 is connected to the first pipeline of the second steam generator 22 through the first pipeline of the steam superheater 21, and the first pipeline of the second steam generator 22 is connected to the inlet of the boiler 8 through the first channel of the fresh air heat exchanger 23; the air duct 6 is connected to the inlet of the incinerator 7 through the blower 24 and the second channel of the fresh air heat exchanger 23. The heat exchange unit in the present invention mainly includes two parts, one is a heat exchange part for heating the desalted water to produce 0.6MPa superheated steam by-product, and the other is used to preheat the air to meet the air preheating part of the incinerator 7; the exhaust heat from the incinerator 7 in the present invention is fully utilized in the heat exchange unit and then enters the boiler 8, and is subsequently processed by the corresponding denitration device and desulfurization device.

[0036] Furthermore, the second pipe inlet of the second steam generator 22 is connected to the low-pressure boiler feed water pipe 17, the second pipe outlet of the second steam generator 22 is connected to the second pipe inlet of the steam superheater 21, and the second pipe outlet of the steam superheater 21 is connected to the 0.6 MPa superheated steam pipe network 25.

[0037] Furthermore, the conversion stripping tail gas unit includes a conversion ammonia washing tower 26, the liquid phase outlet of the conversion ammonia washing tower 26 is connected to the conversion stripping tower 28 through the first channel of the first condenser 27, the gas phase outlet of the conversion stripping tower 28 is connected to the second channel of the first condenser 27 and the first channel of the second condenser 29 and the second gas-liquid separator 30, and the gas phase outlet of the second gas-liquid separator 30 is connected to the incinerator 7.

[0038] Furthermore, the liquid phase outlet of the second gas-liquid separator 30 is connected to the gasification coal grinding device 31 ; the second channel inlet of the second condenser 29 is connected to the circulating water supply pipeline 32 , and the second channel outlet of the second condenser 29 is connected to the circulating water return pipeline 33 .

[0039] A treatment process using a comprehensive waste gas treatment device of a synthetic ammonia system, the process comprising the following steps:

[0040] Step 1: The sulfur-containing tail gas in the sulfur-containing tail gas pipeline 1 of the low-temperature methanol washing device, the oxygen in the low-pressure oxygen pipeline 2 of the air separation device, and the fuel gas in the fuel gas storage tank 3 enter the combustion furnace 4 for combustion, and the flow rate of oxygen entering the combustion furnace 4 is controlled by the corresponding valve on the low-pressure oxygen pipeline 2, thereby controlling the molar ratio of hydrogen sulfide to sulfur dioxide in the tail gas after combustion in the combustion furnace 4 to be lower than 2:1, so as to achieve complete conversion of all hydrogen sulfide gases, and the excess sulfur dioxide is removed by the subsequent desulfurization device 10;

[0041] Step 2: The exhaust gas after combustion in the combustion furnace 4 has the following components: 1.35 hydrogen, 11.7 nitrogen, 3.3 carbon monoxide, 47.12 carbon dioxide, 6.92 hydrogen sulfide, 1.69 carbon oxysulfide, 4.33 sulfur dioxide, and 23.59 water; the exhaust gas after combustion enters the first heat exchange channel of the first steam generator 12 to exchange heat with the desalted water from the low-pressure boiler feed water pipeline 17, and the steam in the second heat exchange channel of the first steam generator 12 after heat exchange enters the 0.5MPa steam network 18, and the exhaust gas after heat exchange enters the first heat exchange channel of the steam heater 14 for heating; the exhaust gas temperature after heat exchange is 170-180°C, and the exhaust gas heated by the steam heater 14 is 240-250°C;

[0042] Step 3: the tail gas heated by the steam heater 14 enters the corresponding sulfur reactor 15 for reaction, the liquid phase after the reaction enters the corresponding sulfur condenser 16 for condensation, and is sent to the liquid sulfur pool 13 for recovery after condensation; the tail gas after the reaction through the sulfur reactor 15 enters the first heat exchange path of the next steam heater 14 for heating; the tail gas entering the first heat exchange path of the next steam heater 14 has the following composition: 1.39 hydrogen, 12.12 nitrogen, 3.46 carbon monoxide, 50.55 carbon dioxide, 2.53 hydrogen sulfide, 0.02 carbon oxysulfide, 1.27 sulfur dioxide, and 28.66 water;

[0043] Step 4: the tail gas enters the first heat exchange passage of the next steam heater 14 for heating. After the tail gas is heated to 205-215° C., it is sent to the corresponding sulfur reactor 15 for reaction. The liquid phase after the reaction enters the corresponding sulfur condenser 16 for condensation. After condensation, it is sent to the liquid sulfur pool 13 for recovery. The tail gas after the reaction in the sulfur reactor 15 enters the first heat exchange passage of the next steam heater 14 for heating. The tail gas entering the first heat exchange passage of the next steam heater 14 has the following composition: 1.43 hydrogen, 12.38 nitrogen, 3.54 carbon monoxide, 51.67 carbon dioxide, 0.58 hydrogen sulfide, 0.02 carbon oxysulfide, 0.29 sulfur dioxide, and 30.09 water.

[0044] Step 5: the tail gas enters the first heat exchange passage of the rear steam heater 14 for heating, and after the tail gas is heated to 200-210° C., it is sent to the corresponding sulfur reactor 15 for reaction, and the liquid phase after the reaction enters the corresponding sulfur condenser 16 for condensation, and after condensation, it is sent to the liquid sulfur pool 13 for recovery; the tail gas after the reaction through the sulfur reactor 15 enters the first gas-liquid separator 5 for gas-liquid separation, the liquid phase separated from the gas and liquid enters the liquid sulfur pool 13 for recovery, and the gas phase separated from the gas and liquid enters the incinerator 7; the tail gas entering the first gas-liquid separator 5 has the following composition: 1.43 hydrogen, 12.46 nitrogen, 3.56 carbon monoxide, 51.99 carbon dioxide, 0.24 hydrogen sulfide, 0.01 carbon oxysulfide, 0.12 sulfur dioxide, and 30.19 water;

[0045] Step 6: The ammonia-containing waste liquid in the conversion ammonia scrubber 26 enters the conversion stripping tower 28 through the first channel of the first condenser 27. The conversion stripping tower 28 strips out the ammonia and non-condensable gas in the waste liquid. The gas phase passes through the gas phase outlet of the conversion stripping tower 28, the second channel of the first condenser 27 and the first channel of the second condenser 29 in sequence and enters the second gas-liquid separator 30 for gas-liquid separation. The liquid phase after gas-liquid separation enters the gasification coal grinding device 31, and the gas phase after gas-liquid separation enters the incinerator 7;

[0046] Step 7: The air in the air duct 6 enters the incinerator 7 through the blower 24 and the second channel of the fresh air heat exchanger 23;

[0047] Step 8: The fuel gas in the fuel gas storage tank 3, the gas phase of the first gas-liquid separator 5 in step 5, the gas phase of the second gas-liquid separator 30 in step 6 and the air passing through the second channel of the fresh air heat exchanger 23 in step 7 enter the incinerator 7 for combustion. The gas composition after incineration in the incinerator 7 is: 34.3% carbon dioxide, 41.9% nitrogen, 17.7% water, 1.1% sulfur dioxide, 5% oxygen, and 200mg / Nm3 of nitrogen oxides, and no longer contains combustible gas;

[0048] Step 9: The gas incinerated by the incinerator 7 passes through the first pipeline of the steam superheater 21, the first pipeline of the second steam generator 22, and the first channel of the fresh air heat exchanger 23 for heat exchange; the gas after heat exchange enters the boiler 8, and then passes through the denitrification device 9 to remove nitrogen oxides in the tail gas, and then passes through the desulfurization device 10 to remove sulfur dioxide in the tail gas, and finally the qualified tail gas is discharged through the chimney 11;

[0049] The desalted water in the low-pressure boiler feed water pipe 17 enters the second pipe of the second steam generator 22 for heat exchange and then enters the second pipe of the steam superheater 21 for further heat exchange. The produced steam enters the 0.6 MPa superheated steam pipe network 25.

[0050] The present invention is a transformation of an existing synthetic ammonia system. According to the properties and characteristics of different waste gases produced in the synthetic ammonia system, part of the tail gas is first burned to recover the heat and sulfur in the tail gas, and then the tail gas after sulfur recovery is mixed with other tail gases and burned in an incinerator to further utilize the heat. Finally, the tail gas is burned in a boiler and cooperates with a denitration device 9 and a desulfurization device 10 to achieve standard emission. The present invention can uniformly treat the waste gas in the synthetic ammonia system, and use the denitration and desulfurization systems of the boiler device to treat the nitrogen oxides and sulfides in the tail gas. No desulfurization and denitration devices with high investment are required to be separately set up, and a linkage design of tail gas treatment of the whole system is realized, thereby saving investment, realizing effective utilization of thermal energy and being environmentally friendly.

[0051] 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:

[0052] Example 1

[0053] A comprehensive waste gas treatment device for a synthetic ammonia system comprises a shift stripping tail gas unit, a sulfur-containing tail gas pipeline 1 of a low-temperature methanol washing device, a low-pressure oxygen pipeline 2 of an air separation device and a fuel gas storage tank 3; the sulfur-containing tail gas pipeline 1 of the low-temperature methanol washing device, the low-pressure oxygen pipeline 2 of the air separation device and the fuel gas storage tank 3 are respectively connected to the inlet of a combustion furnace 4, and the outlet of the combustion furnace 4 is connected to a first gas-liquid separator 5 through a sulfur recovery unit; the gas phase outlet of the first gas-liquid separator 5, the shift stripping tail gas unit, the fuel gas storage tank 3 and the air pipeline 6 are respectively connected to the inlet of an incinerator 7, the outlet of the incinerator 7 is connected to a boiler 8 through a heat exchange unit, and the flue gas outlet of the boiler 8 is connected to a chimney 11 through a denitration device 9 and a desulfurization device 10. The sulfur recovery unit includes a first steam generator 12, the outlet of the combustion furnace 4 is connected to the first heat exchange channel of the first steam generator 12, the liquid phase outlet of the first heat exchange channel is connected to the liquid sulfur pool 13, the gas phase outlet of the first heat exchange channel is connected to a plurality of sulfur recovery components arranged in series, the gas phase outlet of the terminal sulfur recovery component is connected to the first gas-liquid separator 5, and the liquid phase outlet of the first liquid separator 5 is connected to the liquid sulfur pool 13. The sulfur recovery component includes a steam heater 14 and a sulfur reactor 15, the first heat exchange channel inlet of the steam heater 14 is connected to the first heat exchange channel outlet of the first steam generator 12 or the first heat exchange channel outlet of the previous sulfur reactor 15, the first heat exchange channel outlet of the steam heater 14 is connected to the inlet of the corresponding sulfur reactor 15, the material outlet of the sulfur reactor 15 is connected to the liquid sulfur pool 13 through the corresponding sulfur condenser 16, and the gas phase outlet of the sulfur reactor 15 is connected to the first heat exchange channel inlet of the next steam heater 14 or the inlet of the first gas-liquid separator 5. The inlet of the second heat exchange channel of the first steam generator 12 is connected to the low-pressure boiler feed water pipeline 17, and the outlet of the second heat exchange channel of the first steam generator 12 is connected to the 0.5MPa steam network 18. The inlet of the second channel of the steam heater 14 is connected to the 4MPa steam network 19, and the outlet of the second channel of the steam heater 14 is connected to the condensate recovery storage tank 20. The heat exchange unit includes a steam superheater 21, and the outlet of the incinerator 7 is connected to the first pipeline of the second steam generator 22 through the first pipeline of the steam superheater 21, and the first pipeline of the second steam generator 22 is connected to the inlet of the boiler 8 through the first channel of the fresh air heat exchanger 23; the air pipeline 6 is connected to the inlet of the incinerator 7 through the blower 24 and the second channel of the fresh air heat exchanger 23. The inlet of the second pipeline of the second steam generator 22 is connected to the low-pressure boiler feed water pipeline 17, and the outlet of the second pipeline of the second steam generator 22 is connected to the inlet of the second pipeline of the steam superheater 21, and the outlet of the second pipeline of the steam superheater 21 is connected to the 0.6MPa superheated steam network 25.The shift stripping tail gas unit comprises a shift ammonia washing tower 26, the liquid phase outlet of the shift ammonia washing tower 26 is connected to the shift stripping tower 28 through the first channel of the first condenser 27, the gas phase outlet of the shift stripping tower 28 is connected to the second channel of the first condenser 27 and the first channel of the second condenser 29 and the second gas-liquid separator 30, and the gas phase outlet of the second gas-liquid separator 30 is connected to the incinerator 7. The liquid phase outlet of the second gas-liquid separator 30 is connected to the gasification coal grinding device 31; the second channel inlet of the second condenser 29 is connected to the circulating water supply pipeline 32, and the second channel outlet of the second condenser 29 is connected to the circulating water return pipeline 33.

[0054] A treatment process using a comprehensive waste gas treatment device of a synthetic ammonia system, the process comprising the following steps:

[0055] Step 1: The sulfur-containing tail gas in the sulfur-containing tail gas pipeline 1 of the low-temperature methanol washing device, the oxygen in the low-pressure oxygen pipeline 2 of the air separation device, and the fuel gas in the fuel gas storage tank 3 enter the combustion furnace 4 for combustion, and the flow rate of oxygen entering the combustion furnace 4 is controlled by the corresponding valve on the low-pressure oxygen pipeline 2, thereby controlling the molar ratio of hydrogen sulfide to sulfur dioxide in the tail gas after combustion in the combustion furnace 4 to be lower than 2:1, so as to achieve complete conversion of all hydrogen sulfide gases, and the excess sulfur dioxide is removed by the subsequent desulfurization device 10;

[0056] Step 2: The exhaust gas after combustion in the combustion furnace 4 has the following components: 1.35 hydrogen, 11.7 nitrogen, 3.3 carbon monoxide, 47.12 carbon dioxide, 6.92 hydrogen sulfide, 1.69 carbon oxysulfide, 4.33 sulfur dioxide, and 23.59 water; the exhaust gas after combustion enters the first heat exchange channel of the first steam generator 12 to exchange heat with the desalted water from the low-pressure boiler feed water pipeline 17, and the steam in the second heat exchange channel of the first steam generator 12 after heat exchange enters the 0.5MPa steam network 18, and the exhaust gas after heat exchange enters the first heat exchange channel of the steam heater 14 for heating; the exhaust gas temperature after heat exchange is 170°C, and the exhaust gas heated by the steam heater 14 is 240°C;

[0057] Step 3: the tail gas heated by the steam heater 14 enters the corresponding sulfur reactor 15 for reaction, the liquid phase after the reaction enters the corresponding sulfur condenser 16 for condensation, and is sent to the liquid sulfur pool 13 for recovery after condensation; the tail gas after the reaction through the sulfur reactor 15 enters the first heat exchange path of the next steam heater 14 for heating; the tail gas entering the first heat exchange path of the next steam heater 14 has the following composition: 1.39 hydrogen, 12.12 nitrogen, 3.46 carbon monoxide, 50.55 carbon dioxide, 2.53 hydrogen sulfide, 0.02 carbon oxysulfide, 1.27 sulfur dioxide, and 28.66 water;

[0058] Step 4: the tail gas enters the first heat exchange passage of the next steam heater 14 for heating, and after the tail gas is heated to 205° C., it is sent to the corresponding sulfur reactor 15 for reaction, and the liquid phase after the reaction enters the corresponding sulfur condenser 16 for condensation, and after condensation, it is sent to the liquid sulfur pool 13 for recovery; the tail gas after the reaction through the sulfur reactor 15 enters the first heat exchange passage of the next steam heater 14 for heating; the tail gas entering the first heat exchange passage of the next steam heater 14 has the following composition: 1.43 hydrogen, 12.38 nitrogen, 3.54 carbon monoxide, 51.67 carbon dioxide, 0.58 hydrogen sulfide, 0.02 carbon oxysulfide, 0.29 sulfur dioxide, and 30.09 water;

[0059] Step 5: the tail gas enters the first heat exchange passage of the rear steam heater 14 for heating, and after the tail gas is heated to 200° C., it is sent to the corresponding sulfur reactor 15 for reaction, and the liquid phase after the reaction enters the corresponding sulfur condenser 16 for condensation, and after condensation, it is sent to the liquid sulfur pool 13 for recovery; the tail gas after the reaction through the sulfur reactor 15 enters the first gas-liquid separator 5 for gas-liquid separation, the liquid phase separated from the gas and liquid enters the liquid sulfur pool 13 for recovery, and the gas phase separated from the gas and liquid enters the incinerator 7; the tail gas entering the first gas-liquid separator 5 has the following composition: 1.43 hydrogen, 12.46 nitrogen, 3.56 carbon monoxide, 51.99 carbon dioxide, 0.24 hydrogen sulfide, 0.01 carbon oxysulfide, 0.12 sulfur dioxide, and 30.19 water;

[0060] Step 6: The ammonia-containing waste liquid in the conversion ammonia scrubber 26 enters the conversion stripping tower 28 through the first channel of the first condenser 27. The conversion stripping tower 28 strips out the ammonia and non-condensable gas in the waste liquid. The gas phase passes through the gas phase outlet of the conversion stripping tower 28, the second channel of the first condenser 27 and the first channel of the second condenser 29 in sequence and enters the second gas-liquid separator 30 for gas-liquid separation. The liquid phase after gas-liquid separation enters the gasification coal grinding device 31, and the gas phase after gas-liquid separation enters the incinerator 7;

[0061] Step 7: The air in the air duct 6 enters the incinerator 7 through the blower 24 and the second channel of the fresh air heat exchanger 23;

[0062] Step 8: The fuel gas in the fuel gas storage tank 3, the gas phase of the first gas-liquid separator 5 in step 5, the gas phase of the second gas-liquid separator 30 in step 6 and the air passing through the second channel of the fresh air heat exchanger 23 in step 7 enter the incinerator 7 for combustion. The gas composition after incineration in the incinerator 7 is: 34.3% carbon dioxide, 41.9% nitrogen, 17.7% water, 1.1% sulfur dioxide, 5% oxygen, and 200mg / Nm3 of nitrogen oxides, and no longer contains combustible gas;

[0063] Step 9: The gas incinerated by the incinerator 7 passes through the first pipeline of the steam superheater 21, the first pipeline of the second steam generator 22, and the first channel of the fresh air heat exchanger 23 for heat exchange; the gas after heat exchange enters the boiler 8, and then passes through the denitrification device 9 to remove nitrogen oxides in the tail gas, and then passes through the desulfurization device 10 to remove sulfur dioxide in the tail gas, and finally the qualified tail gas is discharged through the chimney 11;

[0064] The desalted water in the low-pressure boiler feed water pipe 17 enters the second pipe of the second steam generator 22 for heat exchange and then enters the second pipe of the steam superheater 21 for further heat exchange. The produced steam enters the 0.6 MPa superheated steam pipe network 25.

[0065] Example 2

[0066] A comprehensive waste gas treatment device for a synthetic ammonia system comprises a shift stripping tail gas unit, a sulfur-containing tail gas pipeline 1 of a low-temperature methanol washing device, a low-pressure oxygen pipeline 2 of an air separation device and a fuel gas storage tank 3; the sulfur-containing tail gas pipeline 1 of the low-temperature methanol washing device, the low-pressure oxygen pipeline 2 of the air separation device and the fuel gas storage tank 3 are respectively connected to the inlet of a combustion furnace 4, and the outlet of the combustion furnace 4 is connected to a first gas-liquid separator 5 through a sulfur recovery unit; the gas phase outlet of the first gas-liquid separator 5, the shift stripping tail gas unit, the fuel gas storage tank 3 and the air pipeline 6 are respectively connected to the inlet of an incinerator 7, the outlet of the incinerator 7 is connected to a boiler 8 through a heat exchange unit, and the flue gas outlet of the boiler 8 is connected to a chimney 11 through a denitration device 9 and a desulfurization device 10. The sulfur recovery unit includes a first steam generator 12, the outlet of the combustion furnace 4 is connected to the first heat exchange channel of the first steam generator 12, the liquid phase outlet of the first heat exchange channel is connected to the liquid sulfur pool 13, the gas phase outlet of the first heat exchange channel is connected to a plurality of sulfur recovery components arranged in series, the gas phase outlet of the terminal sulfur recovery component is connected to the first gas-liquid separator 5, and the liquid phase outlet of the first liquid separator 5 is connected to the liquid sulfur pool 13. The sulfur recovery component includes a steam heater 14 and a sulfur reactor 15, the first heat exchange channel inlet of the steam heater 14 is connected to the first heat exchange channel outlet of the first steam generator 12 or the first heat exchange channel outlet of the previous sulfur reactor 15, the first heat exchange channel outlet of the steam heater 14 is connected to the inlet of the corresponding sulfur reactor 15, the material outlet of the sulfur reactor 15 is connected to the liquid sulfur pool 13 through the corresponding sulfur condenser 16, and the gas phase outlet of the sulfur reactor 15 is connected to the first heat exchange channel inlet of the next steam heater 14 or the inlet of the first gas-liquid separator 5. The inlet of the second heat exchange channel of the first steam generator 12 is connected to the low-pressure boiler feed water pipeline 17, and the outlet of the second heat exchange channel of the first steam generator 12 is connected to the 0.5MPa steam network 18. The inlet of the second channel of the steam heater 14 is connected to the 4MPa steam network 19, and the outlet of the second channel of the steam heater 14 is connected to the condensate recovery storage tank 20. The heat exchange unit includes a steam superheater 21, and the outlet of the incinerator 7 is connected to the first pipeline of the second steam generator 22 through the first pipeline of the steam superheater 21, and the first pipeline of the second steam generator 22 is connected to the inlet of the boiler 8 through the first channel of the fresh air heat exchanger 23; the air pipeline 6 is connected to the inlet of the incinerator 7 through the blower 24 and the second channel of the fresh air heat exchanger 23. The inlet of the second pipeline of the second steam generator 22 is connected to the low-pressure boiler feed water pipeline 17, and the outlet of the second pipeline of the second steam generator 22 is connected to the inlet of the second pipeline of the steam superheater 21, and the outlet of the second pipeline of the steam superheater 21 is connected to the 0.6MPa superheated steam network 25.The shift stripping tail gas unit comprises a shift ammonia washing tower 26, the liquid phase outlet of the shift ammonia washing tower 26 is connected to the shift stripping tower 28 through the first channel of the first condenser 27, the gas phase outlet of the shift stripping tower 28 is connected to the second channel of the first condenser 27 and the first channel of the second condenser 29 and the second gas-liquid separator 30, and the gas phase outlet of the second gas-liquid separator 30 is connected to the incinerator 7. The liquid phase outlet of the second gas-liquid separator 30 is connected to the gasification coal grinding device 31; the second channel inlet of the second condenser 29 is connected to the circulating water supply pipeline 32, and the second channel outlet of the second condenser 29 is connected to the circulating water return pipeline 33.

[0067] A treatment process using a comprehensive waste gas treatment device of a synthetic ammonia system, the process comprising the following steps:

[0068] Step 1: The sulfur-containing tail gas in the sulfur-containing tail gas pipeline 1 of the low-temperature methanol washing device, the oxygen in the low-pressure oxygen pipeline 2 of the air separation device, and the fuel gas in the fuel gas storage tank 3 enter the combustion furnace 4 for combustion, and the flow rate of oxygen entering the combustion furnace 4 is controlled by the corresponding valve on the low-pressure oxygen pipeline 2, thereby controlling the molar ratio of hydrogen sulfide to sulfur dioxide in the tail gas after combustion in the combustion furnace 4 to be lower than 2:1, so as to achieve complete conversion of all hydrogen sulfide gases, and the excess sulfur dioxide is removed by the subsequent desulfurization device 10;

[0069] Step 2: The exhaust gas after combustion in the combustion furnace 4 has the following components: 1.35 hydrogen, 11.7 nitrogen, 3.3 carbon monoxide, 47.12 carbon dioxide, 6.92 hydrogen sulfide, 1.69 carbon oxysulfide, 4.33 sulfur dioxide, and 23.59 water; the exhaust gas after combustion enters the first heat exchange channel of the first steam generator 12 to exchange heat with the desalted water from the low-pressure boiler feed water pipeline 17, and the steam in the second heat exchange channel of the first steam generator 12 after heat exchange enters the 0.5MPa steam network 18, and the exhaust gas after heat exchange enters the first heat exchange channel of the steam heater 14 for heating; the exhaust gas temperature after heat exchange is 180°C, and the exhaust gas heated by the steam heater 14 is 250°C;

[0070] Step 3: the tail gas heated by the steam heater 14 enters the corresponding sulfur reactor 15 for reaction, the liquid phase after the reaction enters the corresponding sulfur condenser 16 for condensation, and is sent to the liquid sulfur pool 13 for recovery after condensation; the tail gas after the reaction through the sulfur reactor 15 enters the first heat exchange path of the next steam heater 14 for heating; the tail gas entering the first heat exchange path of the next steam heater 14 has the following composition: 1.39 hydrogen, 12.12 nitrogen, 3.46 carbon monoxide, 50.55 carbon dioxide, 2.53 hydrogen sulfide, 0.02 carbon oxysulfide, 1.27 sulfur dioxide, and 28.66 water;

[0071] Step 4: the tail gas enters the first heat exchange passage of the next steam heater 14 for heating, and after the tail gas is heated to 215° C., it is sent to the corresponding sulfur reactor 15 for reaction, and the liquid phase after the reaction enters the corresponding sulfur condenser 16 for condensation, and after condensation, it is sent to the liquid sulfur pool 13 for recovery; the tail gas after the reaction through the sulfur reactor 15 enters the first heat exchange passage of the next steam heater 14 for heating; the tail gas entering the first heat exchange passage of the next steam heater 14 has the following composition: 1.43 hydrogen, 12.38 nitrogen, 3.54 carbon monoxide, 51.67 carbon dioxide, 0.58 hydrogen sulfide, 0.02 carbon oxysulfide, 0.29 sulfur dioxide, and 30.09 water;

[0072] Step 5: the tail gas enters the first heat exchange passage of the rear steam heater 14 for heating, and after the tail gas is heated to 210° C., it is sent to the corresponding sulfur reactor 15 for reaction, and the liquid phase after the reaction enters the corresponding sulfur condenser 16 for condensation, and after condensation, it is sent to the liquid sulfur pool 13 for recovery; the tail gas after the reaction through the sulfur reactor 15 enters the first gas-liquid separator 5 for gas-liquid separation, the liquid phase separated from the gas and liquid enters the liquid sulfur pool 13 for recovery, and the gas phase separated from the gas and liquid enters the incinerator 7; the tail gas entering the first gas-liquid separator 5 has the following composition: 1.43 hydrogen, 12.46 nitrogen, 3.56 carbon monoxide, 51.99 carbon dioxide, 0.24 hydrogen sulfide, 0.01 carbon oxysulfide, 0.12 sulfur dioxide, and 30.19 water;

[0073] Step 6: The ammonia-containing waste liquid in the conversion ammonia scrubber 26 enters the conversion stripping tower 28 through the first channel of the first condenser 27. The conversion stripping tower 28 strips out the ammonia and non-condensable gas in the waste liquid. The gas phase passes through the gas phase outlet of the conversion stripping tower 28, the second channel of the first condenser 27 and the first channel of the second condenser 29 in sequence and enters the second gas-liquid separator 30 for gas-liquid separation. The liquid phase after gas-liquid separation enters the gasification coal grinding device 31, and the gas phase after gas-liquid separation enters the incinerator 7;

[0074] Step 7: The air in the air duct 6 enters the incinerator 7 through the blower 24 and the second channel of the fresh air heat exchanger 23;

[0075] Step 8: The fuel gas in the fuel gas storage tank 3, the gas phase of the first gas-liquid separator 5 in step 5, the gas phase of the second gas-liquid separator 30 in step 6 and the air passing through the second channel of the fresh air heat exchanger 23 in step 7 enter the incinerator 7 for combustion. The gas composition after incineration in the incinerator 7 is: 34.3% carbon dioxide, 41.9% nitrogen, 17.7% water, 1.1% sulfur dioxide, 5% oxygen, and 200mg / Nm3 of nitrogen oxides, and no longer contains combustible gas;

[0076] Step 9: The gas incinerated by the incinerator 7 passes through the first pipeline of the steam superheater 21, the first pipeline of the second steam generator 22, and the first channel of the fresh air heat exchanger 23 for heat exchange; the gas after heat exchange enters the boiler 8, and then passes through the denitrification device 9 to remove nitrogen oxides in the tail gas, and then passes through the desulfurization device 10 to remove sulfur dioxide in the tail gas, and finally the qualified tail gas is discharged through the chimney 11;

[0077] The desalted water in the low-pressure boiler feed water pipe 17 enters the second pipe of the second steam generator 22 for heat exchange and then enters the second pipe of the steam superheater 21 for further heat exchange. The produced steam enters the 0.6 MPa superheated steam pipe network 25.

[0078] Example 3

[0079] A comprehensive waste gas treatment device for a synthetic ammonia system comprises a shift stripping tail gas unit, a sulfur-containing tail gas pipeline 1 of a low-temperature methanol washing device, a low-pressure oxygen pipeline 2 of an air separation device and a fuel gas storage tank 3; the sulfur-containing tail gas pipeline 1 of the low-temperature methanol washing device, the low-pressure oxygen pipeline 2 of the air separation device and the fuel gas storage tank 3 are respectively connected to the inlet of a combustion furnace 4, and the outlet of the combustion furnace 4 is connected to a first gas-liquid separator 5 through a sulfur recovery unit; the gas phase outlet of the first gas-liquid separator 5, the shift stripping tail gas unit, the fuel gas storage tank 3 and the air pipeline 6 are respectively connected to the inlet of an incinerator 7, the outlet of the incinerator 7 is connected to a boiler 8 through a heat exchange unit, and the flue gas outlet of the boiler 8 is connected to a chimney 11 through a denitration device 9 and a desulfurization device 10. The sulfur recovery unit includes a first steam generator 12, the outlet of the combustion furnace 4 is connected to the first heat exchange channel of the first steam generator 12, the liquid phase outlet of the first heat exchange channel is connected to the liquid sulfur pool 13, the gas phase outlet of the first heat exchange channel is connected to a plurality of sulfur recovery components arranged in series, the gas phase outlet of the terminal sulfur recovery component is connected to the first gas-liquid separator 5, and the liquid phase outlet of the first liquid separator 5 is connected to the liquid sulfur pool 13. The sulfur recovery component includes a steam heater 14 and a sulfur reactor 15, the first heat exchange channel inlet of the steam heater 14 is connected to the first heat exchange channel outlet of the first steam generator 12 or the first heat exchange channel outlet of the previous sulfur reactor 15, the first heat exchange channel outlet of the steam heater 14 is connected to the inlet of the corresponding sulfur reactor 15, the material outlet of the sulfur reactor 15 is connected to the liquid sulfur pool 13 through the corresponding sulfur condenser 16, and the gas phase outlet of the sulfur reactor 15 is connected to the first heat exchange channel inlet of the next steam heater 14 or the inlet of the first gas-liquid separator 5. The inlet of the second heat exchange channel of the first steam generator 12 is connected to the low-pressure boiler feed water pipeline 17, and the outlet of the second heat exchange channel of the first steam generator 12 is connected to the 0.5MPa steam network 18. The inlet of the second channel of the steam heater 14 is connected to the 4MPa steam network 19, and the outlet of the second channel of the steam heater 14 is connected to the condensate recovery storage tank 20. The heat exchange unit includes a steam superheater 21, and the outlet of the incinerator 7 is connected to the first pipeline of the second steam generator 22 through the first pipeline of the steam superheater 21, and the first pipeline of the second steam generator 22 is connected to the inlet of the boiler 8 through the first channel of the fresh air heat exchanger 23; the air pipeline 6 is connected to the inlet of the incinerator 7 through the blower 24 and the second channel of the fresh air heat exchanger 23. The inlet of the second pipeline of the second steam generator 22 is connected to the low-pressure boiler feed water pipeline 17, and the outlet of the second pipeline of the second steam generator 22 is connected to the inlet of the second pipeline of the steam superheater 21, and the outlet of the second pipeline of the steam superheater 21 is connected to the 0.6MPa superheated steam network 25.The shift stripping tail gas unit comprises a shift ammonia washing tower 26, the liquid phase outlet of the shift ammonia washing tower 26 is connected to the shift stripping tower 28 through the first channel of the first condenser 27, the gas phase outlet of the shift stripping tower 28 is connected to the second channel of the first condenser 27 and the first channel of the second condenser 29 and the second gas-liquid separator 30, and the gas phase outlet of the second gas-liquid separator 30 is connected to the incinerator 7. The liquid phase outlet of the second gas-liquid separator 30 is connected to the gasification coal grinding device 31; the second channel inlet of the second condenser 29 is connected to the circulating water supply pipeline 32, and the second channel outlet of the second condenser 29 is connected to the circulating water return pipeline 33.

[0080] A treatment process using a comprehensive waste gas treatment device of a synthetic ammonia system, the process comprising the following steps:

[0081] Step 1: The sulfur-containing tail gas in the sulfur-containing tail gas pipeline 1 of the low-temperature methanol washing device, the oxygen in the low-pressure oxygen pipeline 2 of the air separation device, and the fuel gas in the fuel gas storage tank 3 enter the combustion furnace 4 for combustion, and the flow rate of oxygen entering the combustion furnace 4 is controlled by the corresponding valve on the low-pressure oxygen pipeline 2, thereby controlling the molar ratio of hydrogen sulfide to sulfur dioxide in the tail gas after combustion in the combustion furnace 4 to be lower than 2:1, so as to achieve complete conversion of all hydrogen sulfide gases, and the excess sulfur dioxide is removed by the subsequent desulfurization device 10;

[0082] Step 2: The exhaust gas after combustion in the combustion furnace 4 has the following components: 1.35 hydrogen, 11.7 nitrogen, 3.3 carbon monoxide, 47.12 carbon dioxide, 6.92 hydrogen sulfide, 1.69 carbon oxysulfide, 4.33 sulfur dioxide, and 23.59 water; the exhaust gas after combustion enters the first heat exchange channel of the first steam generator 12 to exchange heat with the desalted water from the low-pressure boiler feed water pipeline 17, and the steam in the second heat exchange channel of the first steam generator 12 after heat exchange enters the 0.5MPa steam network 18, and the exhaust gas after heat exchange enters the first heat exchange channel of the steam heater 14 for heating; the exhaust gas temperature after heat exchange is 175°C, and the exhaust gas heated by the steam heater 14 is 245°C;

[0083] Step 3: the tail gas heated by the steam heater 14 enters the corresponding sulfur reactor 15 for reaction, the liquid phase after the reaction enters the corresponding sulfur condenser 16 for condensation, and is sent to the liquid sulfur pool 13 for recovery after condensation; the tail gas after the reaction through the sulfur reactor 15 enters the first heat exchange path of the next steam heater 14 for heating; the tail gas entering the first heat exchange path of the next steam heater 14 has the following composition: 1.39 hydrogen, 12.12 nitrogen, 3.46 carbon monoxide, 50.55 carbon dioxide, 2.53 hydrogen sulfide, 0.02 carbon oxysulfide, 1.27 sulfur dioxide, and 28.66 water;

[0084] Step 4: the tail gas enters the first heat exchange passage of the next steam heater 14 for heating, and after the tail gas is heated to 210° C., it is sent to the corresponding sulfur reactor 15 for reaction, and the liquid phase after the reaction enters the corresponding sulfur condenser 16 for condensation, and after condensation, it is sent to the liquid sulfur pool 13 for recovery; the tail gas after the reaction through the sulfur reactor 15 enters the first heat exchange passage of the next steam heater 14 for heating; the tail gas entering the first heat exchange passage of the next steam heater 14 has the following composition: 1.43 hydrogen, 12.38 nitrogen, 3.54 carbon monoxide, 51.67 carbon dioxide, 0.58 hydrogen sulfide, 0.02 carbon oxysulfide, 0.29 sulfur dioxide, and 30.09 water;

[0085] Step 5: the tail gas enters the first heat exchange passage of the rear steam heater 14 for heating, and after the tail gas is heated to 205° C., it is sent to the corresponding sulfur reactor 15 for reaction, and the liquid phase after the reaction enters the corresponding sulfur condenser 16 for condensation, and after condensation, it is sent to the liquid sulfur pool 13 for recovery; the tail gas after the reaction through the sulfur reactor 15 enters the first gas-liquid separator 5 for gas-liquid separation, the liquid phase separated from the gas and liquid enters the liquid sulfur pool 13 for recovery, and the gas phase separated from the gas and liquid enters the incinerator 7; the tail gas entering the first gas-liquid separator 5 has the following composition: 1.43 hydrogen, 12.46 nitrogen, 3.56 carbon monoxide, 51.99 carbon dioxide, 0.24 hydrogen sulfide, 0.01 carbon oxysulfide, 0.12 sulfur dioxide, and 30.19 water;

[0086] Step 6: The ammonia-containing waste liquid in the conversion ammonia scrubber 26 enters the conversion stripping tower 28 through the first channel of the first condenser 27. The conversion stripping tower 28 strips out the ammonia and non-condensable gas in the waste liquid. The gas phase passes through the gas phase outlet of the conversion stripping tower 28, the second channel of the first condenser 27 and the first channel of the second condenser 29 in sequence and enters the second gas-liquid separator 30 for gas-liquid separation. The liquid phase after gas-liquid separation enters the gasification coal grinding device 31, and the gas phase after gas-liquid separation enters the incinerator 7;

[0087] Step 7: The air in the air duct 6 enters the incinerator 7 through the blower 24 and the second channel of the fresh air heat exchanger 23;

[0088] Step 8: The fuel gas in the fuel gas storage tank 3, the gas phase of the first gas-liquid separator 5 in step 5, the gas phase of the second gas-liquid separator 30 in step 6 and the air passing through the second channel of the fresh air heat exchanger 23 in step 7 enter the incinerator 7 for combustion. The gas composition after incineration in the incinerator 7 is: 34.3% carbon dioxide, 41.9% nitrogen, 17.7% water, 1.1% sulfur dioxide, 5% oxygen, and 200mg / Nm3 of nitrogen oxides, and no longer contains combustible gas;

[0089] Step 9: The gas incinerated by the incinerator 7 passes through the first pipeline of the steam superheater 21, the first pipeline of the second steam generator 22, and the first channel of the fresh air heat exchanger 23 for heat exchange; the gas after heat exchange enters the boiler 8, and then passes through the denitrification device 9 to remove nitrogen oxides in the tail gas, and then passes through the desulfurization device 10 to remove sulfur dioxide in the tail gas, and finally the qualified tail gas is discharged through the chimney 11;

[0090] The desalted water in the low-pressure boiler feed water pipe 17 enters the second pipe of the second steam generator 22 for heat exchange and then enters the second pipe of the steam superheater 21 for further heat exchange. The produced steam enters the 0.6 MPa superheated steam pipe network 25.

[0091] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A comprehensive waste gas treatment device for ammonia synthesis system, characterized in that: It includes a conversion stripping tail gas unit, a sulfur-containing tail gas pipeline (1) of a low-temperature methanol washing device, a low-pressure oxygen pipeline (2) of an air separation device, and a fuel gas storage tank (3); The sulfur-containing tail gas pipeline (1) of the low-temperature methanol washing device, the low-pressure oxygen pipeline (2) of the air separation device, and the fuel gas storage tank (3) are respectively connected to the inlet of the combustion furnace (4), and the outlet of the combustion furnace (4) is connected to the first gas-liquid separator (5) through the sulfur recovery unit; The gas phase outlet of the first gas-liquid separator (5), the conversion stripping tail gas unit, the fuel gas storage tank (3) and the air pipeline (6) are respectively connected to the inlet of the incinerator (7); the outlet of the incinerator (7) is connected to the boiler (8) through a heat exchange unit; and the flue gas outlet of the boiler (8) is connected to the chimney (11) through a denitrification device (9) and a desulfurization device (10).

2. The comprehensive waste gas treatment device of a synthetic ammonia system according to claim 1, characterized in that: The sulfur recovery unit comprises a first steam generator (12), an outlet of a combustion furnace (4) is connected to a first heat exchange channel of the first steam generator (12), a liquid phase outlet of the first heat exchange channel is connected to a liquid sulfur pool (13), a gas phase outlet of the first heat exchange channel is connected to a plurality of sulfur recovery components arranged in series, a gas phase outlet of a terminal sulfur recovery component is connected to a first gas-liquid separator (5), and a liquid phase outlet of the first liquid separator (5) is connected to the liquid sulfur pool (13).

3. The comprehensive waste gas treatment device of a synthetic ammonia system according to claim 2, characterized in that: The sulfur recovery unit includes a steam heater (14) and a sulfur reactor (15). The first heat exchange channel inlet of the steam heater (14) is connected to the first heat exchange channel outlet of the first steam generator (12) or the first heat exchange channel outlet of the previous sulfur reactor (15); the first heat exchange channel outlet of the steam heater (14) is connected to the inlet of the corresponding sulfur reactor (15); the material outlet of the sulfur reactor (15) is connected to the liquid sulfur pool (13) through the corresponding sulfur condenser (16); and the gas phase outlet of the sulfur reactor (15) is connected to the first heat exchange channel inlet of the next steam heater (14) or the inlet of the first gas-liquid separator (5).

4. A comprehensive waste gas treatment device for a synthetic ammonia system according to claim 2 or 3, characterized in that: The inlet of the second heat exchange channel of the first steam generator (12) is connected to the low-pressure boiler feed water pipe (17), and the outlet of the second heat exchange channel of the first steam generator (12) is connected to the 0.5 MPa steam pipe network (18).

5. The comprehensive waste gas treatment device for ammonia synthesis system according to claim 3, characterized in that: The second channel inlet of the steam heater (14) in the sulfur recovery unit is connected to the 4MPa steam pipe network (19), and the second channel outlet of the steam heater (14) is connected to the condensate recovery storage tank (20).

6. The comprehensive waste gas treatment device of a synthetic ammonia system according to claim 1, characterized in that: The heat exchange unit includes a steam superheater (21), the outlet of the incinerator (7) is connected to the first pipe of the second steam generator (22) through the first pipe of the steam superheater (21), and the first pipe of the second steam generator (22) is connected to the inlet of the boiler (8) through the first channel of the fresh air heat exchanger (23); The air duct (6) is connected to the inlet of the incinerator (7) through the blower (24) and the second channel of the fresh air heat exchanger (23).

7. The comprehensive waste gas treatment device for ammonia synthesis system according to claim 6, characterized in that: The second pipe inlet of the second steam generator (22) is connected to the low-pressure boiler feed water pipe (17), the second pipe outlet of the second steam generator (22) is connected to the second pipe inlet of the steam superheater (21), and the second pipe outlet of the steam superheater (21) is connected to the 0.6 MPa superheated steam pipe network (25).

8. The comprehensive waste gas treatment device for ammonia synthesis system according to claim 1, characterized in that: The conversion stripping tail gas unit comprises a conversion ammonia washing tower (26), the liquid phase outlet of the conversion ammonia washing tower (26) is connected to the conversion stripping tower (28) through the first channel of the first condenser (27), the gas phase outlet of the conversion stripping tower (28) is connected to the second channel of the first condenser (27) and the first channel of the second condenser (29) and the second gas-liquid separator (30), and the gas phase outlet of the second gas-liquid separator (30) is connected to the incinerator (7).

9. The comprehensive waste gas treatment device of a synthetic ammonia system according to claim 8, characterized in that: The liquid phase outlet of the second gas-liquid separator (30) is connected to the gasification coal grinding device (31); the second channel inlet of the second condenser (29) is connected to the circulating water supply pipe (32), and the second channel outlet of the second condenser (29) is connected to the circulating water return pipe (33).

10. A treatment process using a comprehensive waste gas treatment device for ammonia synthesis system, characterized by: The process includes the following steps: Step 1: The sulfur-containing tail gas in the sulfur-containing tail gas pipeline (1) of the low-temperature methanol washing device, the oxygen in the low-pressure oxygen pipeline (2) of the air separation device, and the fuel gas in the fuel gas storage tank (3) enter the combustion furnace (4) for combustion, and the flow rate of the oxygen entering the combustion furnace (4) is controlled by the corresponding valve on the low-pressure oxygen pipeline (2), thereby controlling the molar ratio of hydrogen sulfide to sulfur dioxide in the tail gas after combustion in the combustion furnace (4) to be lower than 2:1, so as to achieve complete conversion of all hydrogen sulfide gas, and the excess sulfur dioxide is removed by the subsequent desulfurization device (10); Step 2: The exhaust gas after combustion in the combustion furnace (4) has the following components: 1.35% hydrogen, 11.7% nitrogen, 3.3% carbon monoxide, 47.12% carbon dioxide, 6.92% hydrogen sulfide, 1.69% carbon oxysulfide, 4.33% sulfur dioxide, and 23.59% water; the exhaust gas after combustion enters the first heat exchange channel of the first steam generator (12) for heat exchange with the desalted water from the low-pressure boiler feed water pipe (17); after heat exchange, the steam in the second heat exchange channel of the first steam generator (12) enters the 0.5MPa steam pipe network (18), and the exhaust gas after heat exchange enters the first heat exchange channel of the steam heater (14) for heating; the exhaust gas temperature after heat exchange is 170-180°C, and the exhaust gas heated by the steam heater (14) is 240-250°C; Step 3: The tail gas heated by the steam heater (14) enters the corresponding sulfur reactor (15) for reaction, and the liquid phase after the reaction enters the corresponding sulfur condenser (16) for condensation, and after condensation, is sent to the liquid sulfur pool (13) for recovery; the tail gas after the reaction in the sulfur reactor (15) enters the first heat exchange channel of the next steam heater (14) for heating; the tail gas entering the first heat exchange channel of the next steam heater (14) has the following composition: 1.39 hydrogen, 12.12 nitrogen, 3.46 carbon monoxide, 50.55 carbon dioxide, 2.53 hydrogen sulfide, 0.02 carbon oxysulfide, 1.27 sulfur dioxide, and 28.66 water; Step 4: The tail gas enters the first heat exchange channel of the next steam heater (14) for heating. After the tail gas is heated to 205-215°C, it is sent to the corresponding sulfur reactor (15) for reaction. The liquid phase after the reaction enters the corresponding sulfur condenser (16) for condensation. After condensation, it is sent to the liquid sulfur pool (13) for recovery. The tail gas after the reaction in the sulfur reactor (15) enters the first heat exchange channel of the next steam heater (14) for heating. The tail gas entering the first heat exchange channel of the next steam heater (14) has the following composition: 1.43% hydrogen, 12.38% nitrogen, 3.54% carbon monoxide, 51.67% carbon dioxide, 0.58% hydrogen sulfide, 0.02% carbon oxysulfide, 0.29% sulfur dioxide, and 30.09% water. Step 5: The tail gas enters the first heat exchange channel of the next steam heater (14) for heating. After the tail gas is heated to 200-210° C., it is sent to the corresponding sulfur reactor (15) for reaction. The liquid phase after the reaction enters the corresponding sulfur condenser (16) for condensation. After condensation, it is sent to the liquid sulfur pool (13) for recovery. The tail gas after the reaction in the sulfur reactor (15) enters the first gas-liquid separator (5) for gas-liquid separation. The liquid phase separated from the gas-liquid separation enters the liquid sulfur pool (13) for recovery, and the gas phase separated from the gas-liquid separation enters the incinerator (7). The tail gas entering the first gas-liquid separator (5) has the following composition: 1.43% hydrogen, 12.46% nitrogen, 3.56% carbon monoxide, 51.99% carbon dioxide, 0.24% hydrogen sulfide, 0.01% carbon oxysulfide, 0.12% sulfur dioxide, and 30.19% water. Step 6: The ammonia-containing waste liquid in the conversion ammonia washing tower (26) enters the conversion stripping tower (28) through the first channel of the first condenser (27), and the conversion stripping tower (28) strips out the ammonia and non-condensable gas in the waste liquid. The gas phase passes through the gas phase outlet of the conversion stripping tower (28), the second channel of the first condenser (27), and the first channel of the second condenser (29) in sequence and enters the second gas-liquid separator (30) for gas-liquid separation. The liquid phase after gas-liquid separation enters the gasification coal grinding device (31), and the gas phase after gas-liquid separation enters the incinerator (7); Step 7: The air in the air duct (6) enters the incinerator (7) through the blower (24) and the second channel of the fresh air heat exchanger (23); Step 8: The fuel gas in the fuel gas storage tank (3), the gas phase of the first gas-liquid separator (5) in step 5, the gas phase of the second gas-liquid separator (30) in step 6, and the air passing through the second channel of the fresh air heat exchanger (23) in step 7 enter the incinerator (7) for combustion. The gas composition after incineration in the incinerator (7) is: 34.3% carbon dioxide, 41.9% nitrogen, 17.7% water, 1.1% sulfur dioxide, 5% oxygen, and nitrogen oxides at 200mg / Nm3, and no longer contains combustible gas; Step 9: The gas incinerated in the incinerator (7) passes through the first pipe of the steam superheater (21), the first pipe of the second steam generator (22), and the first channel of the fresh air heat exchanger (23) for heat exchange; the gas after heat exchange enters the boiler (8), and then passes through the denitrification device (9) to remove nitrogen oxides in the tail gas, and then passes through the desulfurization device (10) to remove sulfur dioxide in the tail gas, and finally the qualified tail gas is discharged through the chimney (11); The desalted water in the low-pressure boiler feed water pipe (17) enters the second pipe of the second steam generator (22) for heat exchange and then enters the second pipe of the steam superheater (21) for further heat exchange. The produced steam enters the 0.6 MPa superheated steam pipe network (25).

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