Denitration, desulfurization and decarbonization system utilizing coke oven gas
By utilizing the selective catalytic reduction reaction of coke oven gas and sintering flue gas, combined with CO2 absorption and high-temperature combustion, the problems of catalyst deactivation, ammonia leakage and high energy consumption in the existing NH3-SCR technology are solved, and an efficient multi-purpose Collaborative pollutant management and ultra-low emissions.
Patent Information
- Application Number
- CN202420955078.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-06
- Publication Date
- 2025-01-21
- Estimated Expiration
- 2034-05-06
AI Technical Summary
The existing NH3-SCR technology has problems such as catalyst deactivation, secondary pollution caused by ammonia leakage and equipment corrosion during the NOx removal process, and it has high energy consumption.
The denitrification, desulfurization and decarbonization system using coke oven gas is used to carry out selective catalytic reduction reaction between H2, CH4 and CO in the coke oven gas and NOx in the sintering flue gas, combined with CO2 absorption and high-temperature combustion in the combustion chamber, to achieve NOx, CO , collaborative treatment of dioxins and VOCs.
It effectively avoids the use of liquid ammonia, reduces catalyst poisoning and equipment corrosion, reduces system operating costs, and achieves efficient multi-pollutant collaborative treatment to achieve ultra-low emission effects.
Smart Images
Figure CN222368746U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of sintering flue gas treatment, and in particular relates to a denitration, desulfurization and decarbonization system utilizing coke oven gas. Background Art
[0002] NO in the atmosphere x It is one of the main air pollutants, and large amounts of emissions may cause various environmental problems. In the steel smelting process, the flue gas emitted during the sintering process is an industrial waste gas with the largest volume, the most pollutants and the highest concentration. The main air pollutants contained in sintering flue gas are heavy metals such as SO2, NO, Hg, and organic pollutants such as dioxins. Therefore, the control and treatment of sintering flue gas is the focus of energy conservation and emission reduction of air pollutants in the metallurgical industry. Among various denitrification technologies, NH3-SCR is generally considered to be the most effective denitrification technology for eliminating NO due to its high denitrification efficiency. x However, there are also some problems in the NH3-SCR reaction process, such as catalyst deactivation caused by the deposition of ammonium sulfate / ammonium nitrate, secondary pollution caused by NH3 leakage, and equipment corrosion. Therefore, it is necessary to develop an efficient non-ammonia SCR process system to effectively remove NO x It is very urgent.
[0003] In the process of steel smelting, a large amount of blast furnace gas, converter gas and coke oven gas will be produced. Among them, coke oven gas is a high-quality medium calorific value gas fuel with a calorific value of 17 megajoules to 19 megajoules per standard cubic meter. The main components of the gas (volume percentage) are 55% to 60% hydrogen, 23% to 27% methane, 5% to 8% carbon monoxide, etc. They are effective reducing agents for denitrification and can also provide higher heat. Therefore, the coke oven gas SCR coupled desulfurization and decarbonization integrated technology is an ideal strategy for the synergistic removal of multiple pollutants in the steel industry. Utility Model Content
[0004] The utility model aims to utilize coal gas to purify and remove pollutants from smelting tail gas in the steel industry, thereby effectively reducing the energy consumption of collaborative removal of multiple pollutants.
[0005] To this end, the utility model provides a denitration, desulfurization and decarbonization system utilizing coke oven gas, comprising a desulfurization tower, a first coke oven gas pipe, a gas mixing tank, a denitration reactor, a CO2 absorption tower and a combustion chamber; the gas inlet of the gas mixing tank is respectively connected to the gas outlet of the desulfurization tower and the first coke oven gas pipe; the gas outlet of the gas mixing tank is connected to the gas inlet of the denitration reactor; the gas outlet of the denitration reactor is connected to the gas inlet of the combustion chamber; the gas outlet of the combustion chamber is connected to the gas inlet of the CO2 absorption tower.
[0006] Specifically, the above-mentioned denitration, desulfurization and decarbonization system using coke oven gas also includes a preheater; the gas outlet of the gas mixing tank is connected to the inlet of the preheater; the outlet of the preheater is connected to the gas inlet of the denitration reactor.
[0007] Specifically, the above-mentioned denitration, desulfurization and decarbonization system using coke oven gas further includes a second coke oven gas pipe; the second coke oven gas pipe is connected to the gas inlet of the combustion chamber.
[0008] Specifically, the activated coke outlet of the above-mentioned desulfurization tower is connected to an activated coke regeneration tower; the activated coke outlet of the activated coke regeneration tower is connected to the desulfurization tower and the denitrification reactor respectively.
[0009] Specifically, the gas outlet of the activated coke regeneration tower is connected to an acid-making device.
[0010] Specifically, the above-mentioned denitration, desulfurization and decarbonization system using coke oven gas further includes an activated coke silo; the outlet of the activated coke silo is respectively connected to the desulfurization tower and the denitration reactor.
[0011] Specifically, the liquid outlet of the CO2 absorption tower is connected to the CO2 regeneration tower; the liquid outlet of the CO2 regeneration tower is connected to the liquid inlet of the CO2 absorption tower.
[0012] Specifically, the above-mentioned denitrification, desulfurization and decarbonization system utilizing coke oven gas also includes a lean-rich liquid exchanger; the rich liquid inlet of the lean-rich liquid exchanger is connected to the liquid outlet of the CO2 absorption tower, and the rich liquid outlet of the lean-rich liquid exchanger is connected to the liquid inlet of the CO2 regeneration tower; the lean liquid inlet of the lean-rich liquid exchanger is connected to the liquid outlet of the CO2 regeneration tower, and the lean liquid outlet of the lean-rich liquid exchanger is connected to the liquid inlet of the CO2 absorption tower.
[0013] Specifically, a rich liquid heater is connected between the rich liquid outlet of the lean-rich liquid exchanger and the liquid inlet of the CO2 regeneration tower; a lean liquid cooler is connected between the lean liquid outlet of the lean-rich liquid exchanger and the liquid inlet of the CO2 absorption tower.
[0014] Specifically, the above-mentioned denitration, desulfurization and decarbonization system using coke oven gas also includes a dust collector; the gas outlet of the desulfurization tower is connected to the inlet of the dust collector; the outlet of the dust collector is connected to the gas inlet of the gas mixing tank.
[0015] Compared with the prior art, the utility model has the following advantages and beneficial effects:
[0016] (1) The denitrification, desulfurization and decarbonization system using coke oven gas provided by the utility model reduces nitrogen oxides in smelting flue gas with the help of H2, CH4 and CO in the coke oven gas generated during the steel smelting process, thus avoiding the use of liquid ammonia, eliminating the poisoning effect of ammonium sulfate on the catalyst from the source, and also avoiding ammonia corrosion on the equipment and the secondary pollution caused, thereby greatly reducing the operating cost of the system.
[0017] (2) The denitrification, desulfurization and decarbonization system using coke oven gas provided by the utility model leads the denitrified flue gas back to the combustion chamber, so that CO, dioxins and VOCs in the flue gas are purified and removed. The system can achieve NO reduction in sintering flue gas. x , CO, dioxins and VOCs are synergistically treated in the same system, realizing the coordinated governance of multiple pollutants in the steel industry, which will effectively help the steel industry to achieve low cost and ultra-low emissions.
[0018] (3) The denitrification, desulfurization and decarbonization system using coke oven gas provided by the utility model is provided with a coke oven gas split flow, while ensuring NO x Under the condition of removal rate, the second coke oven gas pipe is used to directly introduce the coke oven gas into the burner for combustion. The heat generated can provide energy for the process stages that need heating during the denitrification, desulfurization and decarbonization process, replacing part of the electric heating and steam heating in the decarbonization process, greatly reducing production energy consumption.
[0019] The present invention will be described in further detail below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 The utility model is a schematic diagram of the structure of a denitration, desulfurization and decarbonization system utilizing coke oven gas.
[0021] Explanation of the reference numerals in the drawings: 1. first booster fan; 2. desulfurization tower; 3. activated coke regeneration tower; 4. acid making device; 5. cyclone separator; 6. activated coke silo; 7. dust collector; 8. mixing tank; 9. denitrification reactor; 10. CO2 absorption tower; 11. induced draft fan; 12. lean liquid cooler; 13. chimney; 14. rich liquid heater; 15. CO2 regeneration tower; 16. lean liquid pump; 17. lean and rich liquid exchanger; 18. rich liquid pump; 19. preheater; 20. waste heat boiler; 21. combustion chamber; 22. electromagnetic flowmeter; 23. three-way valve; 24. second booster fan. DETAILED DESCRIPTION
[0022] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0023] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.
[0024] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features; in the description of the present utility model, unless otherwise specified, "plurality" means two or more.
[0025] Reference Figure 1 The utility model provides a denitration, desulfurization and decarbonization system using coke oven gas, comprising a desulfurization tower 2, a first coke oven gas pipe, a gas mixing tank 8, a denitration reactor 9, a CO2 absorption tower 10 and a combustion chamber 21; the gas inlet of the gas mixing tank 8 is respectively connected to the gas outlet of the desulfurization tower 2 and the first coke oven gas pipe; the gas outlet of the gas mixing tank 8 is connected to the gas inlet of the denitration reactor 9; the gas outlet of the denitration reactor 9 is connected to the gas inlet of the combustion chamber 21; the gas outlet of the combustion chamber 21 is connected to the gas inlet of the CO2 absorption tower 10. The denitration reactor 9 is preferably a denitration SCR reactor. Before use, activated coke is filled in the desulfurization tower 2 and the denitration reactor 9, and a composite organic amine solution for absorbing CO2 is loaded in the top spray system of the CO2 absorption tower 10. When in use, the coke oven gas enters the gas mixing tank 8 through the first coke oven gas pipe, and the first coke oven gas pipe is preferably provided with an electromagnetic flowmeter 22, and the required gas volume is controlled by the electromagnetic flowmeter 22. The sintering flue gas enters the desulfurization tower 2 for desulfurization, and the desulfurized flue gas is mixed with the coke oven gas and enters the gas mixing tank 8. The desulfurized flue gas and the coke oven gas mixed evenly in the gas mixing tank 8 enter the denitrification reactor 9, where a selective catalytic reduction reaction occurs under the action of the activated coke to convert NO xThe exhaust gas after the reaction is sent to the combustion chamber 21 for high-temperature combustion to remove pollutants such as CO, dioxins, and VOCs contained therein. The flue gas after combustion enters the CO2 absorption tower 10 from the bottom, and is countercurrently contacted and absorbed with the composite organic amine solution sprayed from the top of the tower. The decarbonized gas after absorbing CO2 is discharged to the outside, and the saturated organic amine solution is discharged from the bottom of the CO2 absorption tower 10. Optionally, the gas outlet of the CO2 absorption tower 10 is connected to a chimney 13, and the connecting pipe between the two is preferably provided with an induced draft fan 11, and the decarbonized gas after absorbing CO2 is discharged from the chimney 13 through the induced draft fan 11.
[0026] Furthermore, the denitration, desulfurization and decarbonization system using coke oven gas further includes a preheater 19; the gas outlet of the gas mixing tank 8 is connected to the inlet of the preheater 19; the outlet of the preheater 19 is connected to the gas inlet of the denitration reactor 9. The desulfurized flue gas and coke oven gas uniformly mixed in the gas mixing tank 8 are heated to a suitable temperature by the preheater 19 and then enter the denitration reactor 9.
[0027] In order to reduce the system operation cost, the active coke outlet of the desulfurization tower 2 is connected to an active coke regeneration tower 3; the active coke outlet of the active coke regeneration tower 3 is respectively connected to the desulfurization tower 2 and the denitration reactor 9. The adsorption saturated active coke in the desulfurization tower 2 is sent to the active coke regeneration tower 3 for regeneration through a conveying chain or other feasible means, and the regenerated active coke is transported back to the desulfurization tower 2 and the denitration reactor 9 through a conveying chain or other feasible means for reuse.
[0028] Optionally, a cyclone separator 5 is provided at the active coke outlet of the active coke regeneration tower 3; the material outlet of the cyclone separator 5 is respectively connected to the desulfurization tower 2 and the denitration reactor 9. The regenerated active coke is screened by the cyclone separator 5 to remove broken coke particles.
[0029] Specifically, the gas outlet of the activated coke regeneration tower 3 is connected to an acid-making device 4. The high-concentration SO2 obtained by analysis in the activated coke regeneration tower 3 is sent to the acid-making device 4 to prepare sulfuric acid products.
[0030] Furthermore, the denitration, desulfurization and decarbonization system using coke oven gas further includes an activated coke silo 6; the outlet of the activated coke silo 6 is respectively connected to the desulfurization tower 2 and the denitration reactor 9. The activated coke silo 6 replenishes activated coke according to actual conditions to ensure that the total amount of activated coke in the desulfurization tower 2 and the denitration reactor 9 remains stable.
[0031] In a detailed embodiment, the liquid outlet of the CO2 absorption tower 10 is connected to the CO2 regeneration tower 15; the liquid outlet of the CO2 regeneration tower 15 is connected to the liquid inlet of the CO2 absorption tower 10. The saturated organic amine solution is discharged from the bottom of the CO2 absorption tower 10 and is introduced into the CO2 regeneration tower 15 through a pipeline for regeneration. The CO2 obtained by analysis can be collected for blast furnace injection or production of chemical products. The lean liquid treated by the CO2 regeneration tower 15 is returned to the CO2 absorption tower 10 for reuse.
[0032] Specifically, the denitrification, desulfurization and decarbonization system utilizing coke oven gas also includes a lean-rich liquid exchanger 17; the rich liquid inlet of the lean-rich liquid exchanger 17 is connected to the liquid outlet of the CO2 absorption tower 10, and the rich liquid outlet of the lean-rich liquid exchanger 17 is connected to the liquid inlet of the CO2 regeneration tower 15; the lean liquid inlet of the lean-rich liquid exchanger 17 is connected to the liquid outlet of the CO2 regeneration tower 15, and the lean liquid outlet of the lean-rich liquid exchanger 17 is connected to the liquid inlet of the CO2 absorption tower 10.
[0033] Preferably, a lean liquid pump 16 is provided between the lean liquid inlet of the lean-rich liquid exchanger 17 and the liquid outlet of the CO2 regeneration tower 15 , and a rich liquid pump 18 is provided between the rich liquid inlet of the lean-rich liquid exchanger 17 and the liquid outlet of the CO2 absorption tower 10 .
[0034] Furthermore, a rich liquid heater 14 is connected between the rich liquid outlet of the lean-rich liquid exchanger 17 and the liquid inlet of the CO2 regeneration tower 15 ; a lean liquid cooler 12 is connected between the lean liquid outlet of the lean-rich liquid exchanger 17 and the liquid inlet of the CO2 absorption tower 10 .
[0035] The saturated organic amine solution is discharged from the bottom of the CO2 absorption tower 10, and is heated by the rich liquid pump 18, the lean-rich liquid exchanger 17 and the rich liquid heater 14 in sequence through the pipeline, and then is regenerated in the CO2 regeneration tower 15. The CO2 obtained by the analysis is collected for blast furnace injection or production of chemical products. The lean liquid at the bottom of the CO2 regeneration tower 15 is cooled by the lean liquid pump 16, the lean-rich liquid exchanger 17 and the cooler, and then returned to the CO2 absorption tower 10 for reuse.
[0036] Furthermore, the denitration, desulfurization and decarbonization system using coke oven gas further includes a dust collector 7; the gas outlet of the desulfurization tower 2 is connected to the inlet of the dust collector 7; the outlet of the dust collector 7 is connected to the gas inlet of the gas mixing tank 8. The dust collector 7 is preferably a bag dust collector 7, and the flue gas desulfurized by the desulfurization tower 2 enters the dust collector 7 for dust and impurity removal and is then sent to the gas mixing tank 8.
[0037] In an optimized implementation, the denitration, desulfurization and decarbonization system using coke oven gas further includes a second coke oven gas pipe; the second coke oven gas pipe is connected to the gas inlet of the combustion chamber 21. The coke oven gas is divided into two streams, one of which is sent to the mixing tank 8 after merging with the desulfurized flue gas through the first coke oven gas pipe, and the other is sent to the combustion chamber 21 through the second coke oven gas pipe to burn and generate heat, providing a heat source for the equipment that needs to be heated in the denitration, desulfurization and decarbonization system, such as the activated coke regeneration tower 3, the preheater 19, the rich liquid heater 14 and the CO2 regeneration tower 15.
[0038] Embodiment 1:
[0039] The present embodiment provides a denitrification, desulfurization and decarbonization system using coke oven gas, including a first booster fan 1, a desulfurization tower 2, an activated coke regeneration tower 3, an acid making device 4, a cyclone separator 5, an activated coke silo 6, a dust collector 7, a mixing tank 8, a denitrification reactor 9, a CO2 absorption tower 10, an induced draft fan 11, a lean liquid cooler 12, a chimney 13, a rich liquid heater 14, a CO2 regeneration tower 15, a lean liquid pump 16, a lean and rich liquid exchanger 17, a rich liquid pump 18, a preheater 19, a waste heat boiler 20, a combustion chamber 21, an electromagnetic flowmeter 22, a three-way valve 23, a second booster fan 24, a first coke oven gas pipe, and a second coke oven gas pipe.
[0040] The first booster fan 1 is connected to the gas inlet of the desulfurization tower 2, and the activated coke outlet of the desulfurization tower 2 is connected to the activated coke regeneration tower 3 through a conveying chain; the activated coke outlet of the activated coke regeneration tower 3 is connected to the inlet of the cyclone separator 5, and the outlet of the cyclone separator 5 is respectively connected to the desulfurization tower 2 and the denitration reactor 9; the gas outlet of the activated coke regeneration tower 3 is connected to the acid making device 4; the outlet of the activated coke silo 6 is respectively connected to the desulfurization tower 2 and the denitration reactor 9. The gas outlet of the desulfurization tower 2 is connected to the gas inlet of the dust collector 7, the gas outlet of the dust collector 7 is connected to the gas inlet of the mixing tank 8, the gas outlet of the mixing tank 8 is connected to the inlet of the preheater 19, and the outlet of the preheater 19 is connected to the gas inlet of the denitration reactor 9; the gas outlet of the denitration reactor 9 is connected to the gas inlet of the combustion chamber 21; the gas outlet of the combustion chamber 21 is connected to the gas inlet of the waste heat boiler 20 and the CO2 absorption tower 10 in sequence; the gas outlet of the CO2 absorption tower 10 is connected to the induced draft fan 11 and the chimney 13 in sequence.
[0041] The second booster fan 24 is connected to the first coke oven gas pipe and the first coke oven gas pipe respectively through the three-way valve 23, and the first coke oven gas pipe is provided with an electromagnetic flowmeter 22; the first coke oven gas pipe is connected to the gas inlet of the mixing tank 8; the second coke oven gas pipe is connected to the gas inlet of the combustion chamber 21; the heat outlet of the combustion chamber 21 is respectively connected to the activated coke regeneration tower 3, the preheater 19, the rich liquid heater 14 and the CO2 regeneration tower 15.
[0042] The rich liquid inlet of the lean-rich liquid exchanger 17 is connected to the liquid outlet of the CO2 absorption tower 10, and the rich liquid outlet of the lean-rich liquid exchanger 17 is connected to the liquid inlet of the CO2 regeneration tower 15; the lean liquid inlet of the lean-rich liquid exchanger 17 is connected to the liquid outlet of the CO2 regeneration tower 15, and the lean liquid outlet of the lean-rich liquid exchanger 17 is connected to the liquid inlet of the CO2 absorption tower 10; a lean liquid pump 16 is provided between the lean liquid inlet of the lean-rich liquid exchanger 17 and the liquid outlet of the CO2 regeneration tower 15, and a rich liquid pump 18 is provided between the rich liquid inlet of the lean-rich liquid exchanger 17 and the liquid outlet of the CO2 absorption tower 10; a rich liquid heater 14 is connected between the rich liquid outlet of the lean-rich liquid exchanger 17 and the liquid inlet of the CO2 regeneration tower 15; a lean liquid cooler 12 is connected between the lean liquid outlet of the lean-rich liquid exchanger 17 and the liquid inlet of the CO2 absorption tower 10.
[0043] The steps of using the denitration, desulfurization and decarbonization system using coke oven gas provided in this embodiment are as follows:
[0044] Step 1: Sintering flue gas enters the desulfurization tower 2 through the first booster fan 1, and the desulfurization tower 2 is filled with an activated coke desulfurizer. The desulfurized flue gas is sent to the gas mixing tank 8 after being dedusted and impurized by the dust collector 7. The adsorption saturated activated coke desulfurizer is sent to the activated coke regeneration tower 3 through a conveyor chain for regeneration, and the high-concentration SO2 obtained by analysis is sent to the acid-making device 4 to prepare sulfuric acid products.
[0045] Step 2: The regenerated activated coke is screened by the cyclone separator 5 to remove the broken coke particles and then transported back to the desulfurization tower 2 and the denitrification reactor 9 through the conveyor chain for reuse. The activated coke silo 6 replenishes the reused activated coke according to the regeneration situation to ensure that the total amount of activated coke in the desulfurization tower 2 and the denitrification reactor 9 remains stable.
[0046] Step 3: After being pressurized by the second booster fan 24, the coke oven gas is divided into two streams in the three-way valve 23. One stream passes through the first coke oven gas pipe, and the required gas volume is controlled by the electromagnetic flowmeter 22. It is merged with the desulfurized flue gas after dust removal by the dust collector 7 and then sent to the mixing tank 8. The other stream is sent to the combustion chamber 21 through the second coke oven gas pipe for combustion to generate heat, providing a heat source for the activated coke regeneration tower 3, the preheater 19, the rich liquid heater 14 and the CO2 regeneration tower 15.
[0047] Step 4: The flue gas and coke oven gas are evenly mixed in the mixing tank 8 and heated in the preheater 19 to reach a suitable temperature, and then enter the denitrification reactor 9 to undergo a selective catalytic reduction reaction under the action of the activated coke catalyst to reduce NO x The tail gas is converted into N2, and the tail gas after the reaction is sent to the combustion chamber 21 for high-temperature combustion to remove pollutants such as CO, dioxins, and VOCs contained therein.
[0048] Step 5: The flue gas after combustion enters the CO2 absorption tower 10 from the bottom, and is countercurrently contacted and absorbed with the composite organic amine solution sprayed from the top of the tower. The decarbonized gas after absorbing CO2 is discharged from the chimney 13 through the induced draft fan 11. The saturated organic amine solution is discharged from the bottom of the CO2 absorption tower 10, and is heated by the rich liquid pump 18, the lean-rich liquid exchanger 17 and the rich liquid heater 14 through the pipeline in sequence, and then is merged into the CO2 regeneration tower 15 for regeneration. The CO2 obtained by analysis is collected for blast furnace injection or production of chemical products. The lean liquid at the bottom of the CO2 regeneration tower 15 is cooled by the lean liquid pump 16, the lean-rich liquid exchanger 17 and the lean liquid cooler 12, and then returned to the CO2 absorption tower 10 for reuse.
[0049] The denitration, desulfurization and decarbonization system using coke oven gas provided in this embodiment can achieve a denitration efficiency of ≥92%, a desulfurization efficiency of ≥93%, and a decarbonization efficiency of ≥95%.
[0050] The above examples are merely illustrative of the present invention and do not constitute a limitation on the protection scope of the present invention. All designs that are identical or similar to the present invention fall within the protection scope of the present invention.
Claims
1. A denitration, desulfurization and decarbonization system utilizing coke oven gas, characterized in that: It comprises a desulfurization tower (2), a first coke oven gas pipe, a gas mixing tank (8), a denitration reactor (9), a CO2 absorption tower (10) and a combustion chamber (21); the gas inlet of the gas mixing tank (8) is respectively connected to the gas outlet of the desulfurization tower (2) and the first coke oven gas pipe; the gas outlet of the gas mixing tank (8) is connected to the gas inlet of the denitration reactor (9); the gas outlet of the denitration reactor (9) is connected to the gas inlet of the combustion chamber (21); and the gas outlet of the combustion chamber (21) is connected to the gas inlet of the CO2 absorption tower (10).
2. The denitration, desulfurization and decarbonization system using coke oven gas as claimed in claim 1, characterized in that: It also includes a preheater (19); the gas outlet of the gas mixing tank (8) is connected to the inlet of the preheater (19); the outlet of the preheater (19) is connected to the gas inlet of the denitration reactor (9).
3. The denitration, desulfurization and decarbonization system using coke oven gas as claimed in claim 1, characterized in that: It also includes a second coke oven gas pipe; the second coke oven gas pipe is connected to the gas inlet of the combustion chamber (21).
4. The denitration, desulfurization and decarbonization system using coke oven gas as claimed in claim 1, characterized in that: The activated coke outlet of the desulfurization tower (2) is connected to an activated coke regeneration tower (3); the activated coke outlet of the activated coke regeneration tower (3) is connected to the desulfurization tower (2) and the denitrification reactor (9) respectively.
5. The denitration, desulfurization and decarbonization system using coke oven gas as claimed in claim 4, characterized in that: The gas outlet of the activated coke regeneration tower (3) is connected to an acid-making device (4).
6. The denitration, desulfurization and decarbonization system using coke oven gas as claimed in claim 1, characterized in that: It also includes an activated coke silo (6); the outlet of the activated coke silo (6) is connected to the desulfurization tower (2) and the denitration reactor (9) respectively.
7. The denitration, desulfurization and decarbonization system using coke oven gas as claimed in claim 1, characterized in that: The liquid outlet of the CO2 absorption tower (10) is connected to the CO2 regeneration tower (15); the liquid outlet of the CO2 regeneration tower (15) is in communication with the liquid inlet of the CO2 absorption tower (10).
8. The denitration, desulfurization and decarbonization system using coke oven gas as claimed in claim 7, characterized in that: It also includes a lean-rich liquid exchanger (17); the rich liquid inlet of the lean-rich liquid exchanger (17) is connected to the liquid outlet of the CO2 absorption tower (10), and the rich liquid outlet of the lean-rich liquid exchanger (17) is connected to the liquid inlet of the CO2 regeneration tower (15); the lean liquid inlet of the lean-rich liquid exchanger (17) is connected to the liquid outlet of the CO2 regeneration tower (15), and the lean liquid outlet of the lean-rich liquid exchanger (17) is connected to the liquid inlet of the CO2 absorption tower (10).
9. The denitration, desulfurization and decarbonization system using coke oven gas as claimed in claim 8, characterized in that: A rich liquid heater (14) is connected between the rich liquid outlet of the lean-rich liquid exchanger (17) and the liquid inlet of the CO2 regeneration tower (15); a lean liquid cooler (12) is connected between the lean liquid outlet of the lean-rich liquid exchanger (17) and the liquid inlet of the CO2 absorption tower (10).
10. The denitration, desulfurization and decarbonization system using coke oven gas as claimed in claim 1, characterized in that: It also includes a dust collector (7); the gas outlet of the desulfurization tower (2) is connected to the inlet of the dust collector (7); the outlet of the dust collector (7) is connected to the gas inlet of the gas mixing tank (8).