Sintering flue gas treatment system and method for reducing CO emission

Abstract

The invention relates to a sintering flue gas treatment system and method for reducing CO emission. The sintering flue gas treatment system comprises a first flue gas treatment loop, a second flue gas treatment loop, a main flue gas treatment loop, a first detector group, a second detector group, a third detector group, a controller and the like. Waste flue gas of the low-temperature working section of the sintering machine is extracted through the first flue gas treatment loop and fed into a combustion area of the high-temperature working section of the sintering machine to participate in combustion, and CO contained in the waste flue gas is oxidized into CO2; waste flue gas of the sintering machine high-temperature section is extracted through a second flue gas treatment loop and fed into a combustion area of the sintering machine low-temperature section to participate in combustion, and high-temperature heat is provided for the low-temperature section; and the main flue gas treatment loop is used for carrying out heat exchange and temperature rise on the extracted flue gas through the circular cooler, and CO contained in the flue gas is oxidized into CO2. According to the invention, the CO in the sintering flue gas is efficiently removed, the operation is simple, convenient and flexible, the flue gas waste heat utilization is realized, and the removal efficiency of the CO in the sintering waste flue gas is improved.

Description

Technical Field

[0001] The invention relates to a sintering fume treatment system, in particular to a sintering fume treatment system and a treatment method for reducing CO emission. Background Art

[0002] The sintering process of steel production is to use a sintering machine to sinter the ore powder into a sintered ore with larger particle size, porous structure and greater strength. The sintering process will produce serious flue gas emissions, and its emissions can reach more than 80% of the total emissions of the steel industry. The CO in the sintering flue gas mainly comes from the incomplete combustion of fuel carbon during the sintering process. On the one hand, this will lead to a decrease in the utilization rate of fuel carbon, and on the other hand, it will also cause serious air pollution. The removal of CO in sintering flue gas is more effective than that of NO x It is more difficult to remove pollutants such as NO x The commonly used tail gas end treatment method is also not suitable for the removal of CO in sintering flue gas. The sintering process uses exhaust operation, resulting in a huge amount of flue gas emissions. At the same time, the dust content in the sintering flue gas is high, and it also contains dioxins and heavy metal elements, which correspondingly increases the difficulty of removing CO. In addition, due to the fluctuations in the sintering raw materials and the working conditions of the sintering machine itself, the flue gas composition fluctuates greatly during the production process, which also increases the difficulty of removing CO from the sintering flue gas.

[0003] At present, the treatment of CO in the waste flue gas of sintering machines usually adopts the internal circulation method or the external circulation method. The internal circulation method generally adopts a separate variable frequency circulation fan to directly extract the flue gas with high CO concentration in the wind box branch pipe. The variable frequency circulation fan mostly adopts a full pressure of 18KPa, and its power is not less than 30% of the total air volume of the two main exhaust fans. The extracted waste flue gas is directly circulated to the surface of the trolley through a multi-tube dust collector for re-combustion to reduce the total amount of CO in the flue gas. Its characteristics are large equipment investment and high operating costs. The external circulation method generally extracts 20~30% of the waste flue gas directly from the outlet of the two main exhaust fans and mixes it into the surface of the trolley for re-combustion to reduce the total amount of CO in the flue gas. Its characteristic is that it cannot eliminate the wind box branch pipe with high CO content in a targeted manner, and can only eliminate the CO in the total amount of flue gas after mixing in the flue. Its characteristic is that the operation effect is poor and it cannot be treated from the source.

[0004] The main purpose of the traditional flue gas circulation method is to reduce the total flue gas emissions of sintering production, reduce heat loss, and, in the process of flue gas circulation, make nitrogen oxides and sulfur oxides undergo secondary chemical reactions, converting some harmful substances into harmless substances, thereby reducing the emission of harmful substances. However, the flue gas circulation method is not specifically aimed at CO in sintering flue gas and cannot achieve low-concentration CO emissions.

[0005] In addition, another method to reduce the CO in the waste flue gas of the sintering machine is the oxidation catalytic method at the end of the flue gas, that is, using a catalyst to oxidize the CO in the waste flue gas to reduce the CO content in the flue gas. However, the catalysts currently used generally have the problem of SO2 poisoning. The sintering machine burns a large amount of coal or coke powder, and the sulfur content of the flue gas is high and unstable. The service life of the catalyst is difficult to guarantee, and it will fail after a long time. If it is not replaced in time, it will affect the use effect. Summary of the invention

[0006] The purpose of the present invention is to provide a sintering flue gas treatment system and method for reducing CO emissions, so as to solve the problem that the existing sintering flue gas treatment system cannot effectively reduce the CO content in the waste flue gas.

[0007] The object of the present invention is achieved in that: A sintering flue gas treatment system for reducing CO emissions, comprising: The first flue gas treatment loop has one end connected to a plurality of wind boxes arranged below the low-temperature section of the sintering machine, and the other end penetrates the sintering machine flue gas hood and enters the combustion area of ​​the high-temperature section of the sintering machine; the first regulating valve, the first dust collector, the first circulating fan and the first fresh air supply pipe are respectively connected in the treatment loop, and the first fresh air supply pipe is connected to the air supply valve; a first detector group, arranged in the first flue gas treatment circuit, including a temperature detector, a flow detector, an oxygen detector and a CO detector, for detecting the temperature and flow of the waste flue gas entering the first flue gas treatment circuit and the concentration of oxygen and CO contained in the waste flue gas, and sending detection information to the controller; The second flue gas treatment loop has one end connected to a plurality of wind boxes arranged below the high-temperature section of the sintering machine, and the other end penetrates the sintering machine fume hood and enters the combustion area of ​​the low-temperature section of the sintering machine; the second regulating valve, the second dust collector, the second circulating fan and the second fresh air supply pipe are respectively connected in the treatment loop, and the second fresh air supply pipe is connected to the air supply valve; a second detector group, arranged in the second flue gas treatment circuit, including a temperature detector, a flow detector, an oxygen detector and a CO detector, for detecting the temperature and flow of the waste flue gas entering the second flue gas treatment circuit and the concentration of oxygen and CO contained in the waste flue gas, and sending detection information to the controller; and The controller is electrically connected to the first regulating valve, the second regulating valve, the air supply valves on the two fresh air supply pipes, the detectors in the first detector group and the detectors in the second detector group respectively; the controller is used to receive the detection information sent by each detector, and perform at least the following three controls according to the detection information and process requirements: first, control the flue gas flow rate of the first flue gas treatment circuit to circulate the waste flue gas extracted from the low-temperature section of the sintering machine to the combustion zone of the high-temperature section of the sintering machine; second, control the flue gas flow rate of the second flue gas treatment circuit to circulate the waste flue gas extracted from the high-temperature section of the sintering machine to the combustion zone of the low-temperature section of the sintering machine; third, control the air supplement amount of the first fresh air supply pipe and the second fresh air supply pipe to adjust the oxygen content in the two circulating flue gases to ensure normal combustion in the combustion zone of the sintering machine.

[0008] Furthermore, the sintering fume treatment system of the present invention further comprises: The main flue gas treatment circuit includes a front section and a rear section; one end of the front section is connected to the other wind boxes in the sintering machine that participate in the above two flue gas cycles, and the other end is connected to the air inlet of the cooling section of the ring cooler; the main exhaust fan, the third dust collector and the desulfurization system are respectively connected in the front section of the circuit; the rear section of the circuit is connected from the air outlet of the ring cooler to the chimney, and the fourth dust collector, the denitrification system and the induced draft fan are respectively connected in the rear section of the circuit; and The third detector group is arranged in the front section of the loop, and includes a temperature detector, a flow detector, an oxygen detector and a CO detector which are electrically connected to the controller respectively, and is used to detect the temperature and flow of the waste flue gas entering the main flue gas treatment loop and the concentration of oxygen and CO contained in the waste flue gas, and send the detection information to the controller.

[0009] Furthermore, a first oxygen content detector electrically connected to the controller is connected in the first flue gas treatment circuit to send detection information of oxygen concentration in the waste flue gas passed into the high-temperature section of the sintering machine to the controller. The controller controls the opening and closing and the opening size of the air supply valve on the first fresh air supply pipe accordingly, so that the oxygen concentration in the circulating flue gas is not less than 18%.

[0010] Furthermore, a second oxygen content detector electrically connected to the controller is connected in the second flue gas treatment circuit to send the detection information of the oxygen concentration in the waste flue gas introduced into the low-temperature section of the sintering machine to the controller. The controller controls the opening and closing and the opening size of the air supply valve on the second fresh air supply pipe accordingly, so that the oxygen concentration in the circulating flue gas is not less than 18%.

[0011] The sintering flue gas treatment system of the present invention sets a three-way flue gas treatment loop on the sintering machine, and adjusts the amount of flue gas entering the recirculation according to parameters such as the temperature, flow rate, oxygen content and CO concentration of the waste flue gas. In this way, firstly, the waste flue gas generated by the low-temperature section of the sintering machine that produces high CO content can be circulated to the high-temperature section of the sintering machine to participate in secondary combustion, so that the CO in the waste flue gas is fully oxidized into CO2, thereby greatly reducing the CO concentration in the waste flue gas; secondly, the waste flue gas generated by the high-temperature section of the sintering machine that produces high heat can be circulated to the high-temperature section of the sintering machine to participate in secondary combustion. The low-temperature section of the machine participates in the combustion to increase the combustion temperature of the low-temperature section, promote the full combustion of the combustion carbon in the low-temperature section, and achieve energy saving and consumption reduction; thirdly, the main flue gas that does not participate in the circulation enters the ring cooling system after desulfurization, and undergoes heat exchange treatment with the high-temperature sintered ore passed into the ring cooler. After heat exchange and temperature increase, dust removal and denitrification are performed, thereby achieving energy saving and consumption reduction in the high-temperature denitrification link, and also causing the CO in the waste flue gas to undergo partial redox reaction with the sintered ore in the ring cooler, further reducing the CO content in the exhaust gas and reducing the blast furnace coke ratio of the next process.

[0012] The sintering flue gas treatment system of the present invention monitors the temperature, flow, CO concentration, oxygen content and other parameters of the flue gas in the three flue gas treatment circuits in real time through a controller, and dynamically adjusts the damper of each circulating fan and the opening of each regulating valve to achieve coordinated control of the comprehensive parameters in the sintering machine fume hood, thereby reducing CO emissions, saving coal resources and reducing production costs.

[0013] The present invention realizes ultra-low emission of CO from sintering machine flue gas, which not only reduces the emission of pollutants, but also greatly reduces carbon emissions, with significant energy-saving effects. In addition, the present invention also fundamentally solves the problem of CO emission from sintering machines from the source, without the use of consumables and related subsequent costs.

[0014] The purpose of the present invention can also be achieved like this: A sintering flue gas treatment method for reducing CO emissions comprises the following steps: S1. Setting up a sintering fume treatment system for reducing CO emissions according to the present invention.

[0015] S2. The first circulation fan in the first flue gas treatment circuit is used to extract the waste flue gas from the low-temperature section of the sintering machine to participate in the flue gas circulation. After the waste flue gas is dust-removed and purified by the first dust collector, it enters the combustion zone of the high-temperature section of the sintering machine to participate in combustion, so that the CO contained therein is oxidized into CO2.

[0016] S3. The second circulation fan in the second flue gas treatment circuit is used to extract the waste flue gas from the high-temperature section of the sintering machine to participate in the flue gas circulation. After the waste flue gas is purified by the second dust collector, it enters the combustion zone of the low-temperature section of the sintering machine to participate in combustion, providing high-temperature heat for the low-temperature section.

[0017] The sintering fume treatment method of the present invention further comprises the following steps: S4. Use the main exhaust fan in the main flue gas treatment circuit to extract the waste flue gas from other wind boxes in the sintering machine that are not involved in the flue gas circulation and treat it as follows: first pass through the third dust collector for dust removal and purification, then pass through the desulfurization system for SO2 removal, and then enter the ring cooler, in the cooling section of the ring cooler, heat exchange and oxidation-reduction reaction are carried out with the high-temperature sintered ore entering the ring cooler. The waste flue gas discharged from the air outlet of the ring cooler is first passed through the fourth dust collector for dust removal and purification under the suction action of the induced draft fan, and then enters the denitrification system for NO x is removed and finally discharged into the atmosphere through the chimney.

[0018] The sintering flue gas treatment method of the present invention realizes the efficient removal of CO in the sintering flue gas without changing the combustion mode of the sintering machine and the quality of the sintered ore. The operation is simple and flexible, the change to the original sintering flue gas treatment system is minimal, and the operation cost is low. The circulation volume of the flue gas can also be dynamically adjusted to realize the waste heat utilization of the flue gas, and the energy consumption of the sintering process and the denitrification process is reduced. In addition, the removal efficiency of CO in the sintering waste flue gas is improved, and the application prospect is broad. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the sintering fume treatment system of the present invention.

[0020] In the figure: 1. trolley, 2. flue gas hood, 3. bellows, 4. low temperature section, 5. high temperature section, 6. front section of the loop, 7. first flue gas treatment loop, 8. second flue gas treatment loop, 9. first regulating valve, 10. second regulating valve, 11. first dust collector, 12. second dust collector, 13. first circulating fan, 14. second circulating fan, 15. ring cooler, 16. air supply valve, 17. third dust collector, 18. first fresh air supply pipe, 19. rear section of the loop, 20. main exhaust fan, 21. second fresh air supply pipe, 22. first detector group, 23. second detector group, 24. third detector group, 25. first oxygen content detector, 26. second oxygen content detector, 27. desulfurization system, 28. induced draft fan, 29. fourth dust collector, 30. denitrification system, 31. chimney. DETAILED DESCRIPTION

[0021] The present invention will be further described below in conjunction with the accompanying drawings.

[0022] like Figure 1As shown, the existing sintering system includes a sintering machine, a trolley 1, a fume hood 2, a bellows 3, an annular cooler 15 and a sintering fume treatment system. The trolley 1 is fully loaded with iron ore powder and coke and continuously passes through the sintering machine, where sintering is performed to form sintered ore. The fume hood 2 is arranged at the upper part of the sintering machine, a row of evenly distributed bellows 3 is arranged at the lower part of the sintering machine, and the annular cooler 15 is connected to the tail end of the sintering machine. After passing through the sintering machine, the trolley 1 enters the annular cooler 15 for heat exchange. Therefore, the front section of the sintering machine is the low-temperature section 4, and the rear section is the high-temperature section 5.

[0023] The sintering flue gas treatment system of the present invention comprises a first flue gas treatment circuit 7, a second flue gas treatment circuit 8, a main flue gas treatment circuit (6, 19), a controller (not shown), etc. The controller may be a conventional industrial computer.

[0024] Figure 1 In the embodiment, one end of the first flue gas treatment loop 7 is connected to a plurality of wind boxes 3 arranged below the low-temperature section 4 of the sintering machine, and the other end passes through the flue gas hood 2 of the sintering machine and enters the combustion zone of the high-temperature section 5 of the sintering machine. The first regulating valve 9, the first dust collector 11 and the first circulating fan 13 are respectively connected to the first flue gas treatment loop 7. The first circulating fan 13 is used to extract waste flue gas from the wind box 3 connected to the bottom of the low-temperature section 4. The temperature of the waste flue gas generated in the low-temperature section is relatively low. The first regulating valve 9 is used to adjust the amount of waste flue gas entering the first flue gas treatment loop 7 under the control of the controller. The first dust collector 11 is used to perform dust removal and purification treatment on the waste flue gas entering the first flue gas treatment loop 7.

[0025] A first detector group 22 is provided in the first flue gas treatment loop 7. The first detector group 22 includes a temperature detector, a flow detector, an oxygen detector and a CO detector, which are used to detect the temperature and flow of the waste flue gas entering the first flue gas treatment loop 7 and the concentrations of oxygen and CO contained in the waste flue gas, and send detection information to the controller.

[0026] The first flue gas treatment loop 7 is also connected to a first fresh air supply pipe 18, and an air supply valve 16 is connected to the first fresh air supply pipe 18. A first oxygen content detector 25 is also connected to the first flue gas treatment loop 7, and the first oxygen content detector 25 is electrically connected to the controller. When the first oxygen content detector 25 detects that the oxygen concentration in the waste flue gas entering the high-temperature section 5 of the sintering machine is low, the controller controls the air supply valve 16 on the first fresh air supply pipe to open, and adjusts the appropriate opening so that the first fresh air supply pipe 18 supplies air to the first flue gas treatment loop 7, so that the oxygen concentration in the circulating flue gas entering the high-temperature section 5 is not less than 18%.

[0027] Figure 1In the embodiment, one end of the second flue gas treatment loop 8 is connected to a plurality of wind boxes 3 arranged below the high temperature section 5 of the sintering machine, and the other end passes through the flue gas hood 2 of the sintering machine and enters the combustion zone of the low temperature section 4 of the sintering machine. The second regulating valve 10, the second dust collector 12 and the second circulating fan 14 are respectively connected to the second flue gas treatment loop 8. The second circulating fan 14 is used to extract waste flue gas from the wind box 3 connected to the bottom of the high temperature section 5. The temperature of the waste flue gas generated in the high temperature section is very high. The second regulating valve 10 is used to adjust the amount of waste flue gas entering the second flue gas treatment loop 8 under the control of the controller. The second dust collector 12 is used to perform dust removal and purification treatment on the waste flue gas entering the second flue gas treatment loop 8.

[0028] A second detector group 23 is provided in the second flue gas treatment loop 8. The second detector group 23 includes a temperature detector, a flow detector, an oxygen detector and a CO detector, which are used to detect the temperature and flow of the waste flue gas entering the second flue gas treatment loop 8 and the concentrations of oxygen and CO contained in the waste flue gas, and send detection information to the controller.

[0029] A second fresh air supply pipe 21 is also connected to the second flue gas treatment circuit 8, and a supply valve 16 is connected to the second fresh air supply pipe 21. A second oxygen content detector 26 is also connected to the second flue gas treatment circuit 8, and the second oxygen content detector 26 is electrically connected to the controller. When the second oxygen content detector 26 detects that the oxygen concentration in the waste flue gas entering the low-temperature section 4 of the sintering machine is low, the controller controls the supply valve 16 on the second fresh air supply pipe to open, and adjusts the appropriate opening so that the second fresh air supply pipe 21 supplies air to the second flue gas treatment circuit 8, so that the oxygen concentration in the circulating flue gas entering the low-temperature section 4 is not less than 18%.

[0030] Figure 1 In the figure, the main flue gas treatment loop includes two components: the front section 6 of the loop and the back section 19 of the loop. One end of the front section 6 of the loop is connected to the other wind boxes 3 in the sintering machine that participate in the flue gas circulation, and the other end is connected to the air inlet of the cooling section of the ring cooler 15. The main exhaust fan 20, the third dust collector 17 and the desulfurization system 27 are respectively connected to the front section 6 of the loop. The back section 19 of the loop is connected from the air outlet of the ring cooler 15 to the chimney 31, and the fourth dust collector 29, the denitrification system 30 and the induced draft fan 28 are respectively connected to the back section 19 of the loop. The desulfurization system 27 and the denitrification system 30 used here are both conventional treatment systems.

[0031] The main exhaust fan 20 is used to extract the waste flue gas from each wind box 3 that is not involved in the flue gas circulation. The third dust collector 17 is used to remove dust from the waste flue gas entering the desulfurization system 27. The fourth dust collector 29 is used to remove dust from the waste flue gas entering the denitrification system 30. The induced draft fan 28 is used to extract the waste flue gas that has been heated by heat exchange from the outlet of the annular cooler. The desulfurization system 27 is used to desulfurize the waste flue gas after dust removal. The denitrification system 30 is used to remove NO from the waste flue gas after dust removal. x removal treatment.

[0032] A third detector group 24 is provided in the front section 6 of the main flue gas treatment loop. The third detector group 24 includes a temperature detector, a flow detector, an oxygen detector and a CO detector, which are used to detect the temperature and flow of the waste flue gas entering the main flue gas treatment loop and the concentration of oxygen and CO contained in the waste flue gas, and send the detection information to the controller.

[0033] The controller provided in the sintering fume treatment system of the present invention is electrically connected to each detector in the first detector group 22, each detector in the second detector group 23, each detector in the third detector group 24, the first oxygen content detector 25, the second oxygen content detector 26, the first regulating valve 9, the second regulating valve 10 and the two air supply valves 16. Each detector transmits detection information to the controller, and the controller controls the opening and closing and the opening size of each regulating valve and the air supply valve.

[0034] The controller performs the following three controls based on the detection information and process requirements: First, it controls the on / off and opening size of the first regulating valve 9 in the first flue gas treatment circuit 7, so as to circulate the waste flue gas extracted from the low-temperature section 4 of the sintering machine to the combustion zone of the high-temperature section 5 of the sintering machine; second, it controls the on / off and opening size of the second regulating valve 10 in the second flue gas treatment circuit 8, so as to circulate the waste flue gas extracted from the high-temperature section 5 of the sintering machine to the combustion zone of the low-temperature section 4 of the sintering machine; third, it controls the opening and closing and opening size of the air supply valves on the first fresh air supply pipe 18 and the second fresh air supply pipe 21, so as to control the air supply amount of the two air supply pipelines, thereby adjusting the oxygen content in the two circulating flue gases of the first flue gas treatment circuit 7 and the second flue gas treatment circuit 8, and ensuring the normal combustion of the combustion zone of the sintering machine.

[0035] The sintering fume treatment method of the present invention comprises the following steps: S1. Setting up the sintering fume treatment system of the present invention.

[0036] S2. The first circulation fan 13 in the first flue gas treatment loop 7 is used to extract the waste flue gas from the low-temperature section 4 of the sintering machine to participate in the flue gas circulation. After the waste flue gas is dust-removed and purified by the first dust collector 11, it enters the combustion area of ​​the high-temperature section 5 through the rear section of the sintering machine flue gas hood 2 to participate in combustion, so that the CO contained in the circulating flue gas is oxidized into CO2.

[0037] S3. The second circulation fan 14 in the second flue gas treatment circuit 8 is used to extract the waste flue gas from the high-temperature section 5 of the sintering machine to participate in the circulation. After the waste flue gas is dust-removed and purified by the second dust collector 12, it enters the combustion area of ​​the low-temperature section 4 through the front hood of the flue gas hood 2 to participate in combustion, thereby providing high-temperature heat for the low-temperature section 4.

[0038] S4. Use the main exhaust fan 20 in the main flue gas treatment circuit to extract the waste flue gas in each wind box 3 in the sintering machine that is not involved in the circulation and treat it as follows: first pass through the third dust collector 17 for dust removal and purification, then pass through the desulfurization system 27 for SO2 removal, then pass through the induced draft fan 28 to pressurize and send it to the ring cooler 15, and in the cooling section of the ring cooler 15, heat exchange and oxidation-reduction reaction are carried out with the high-temperature sintered ore entering the ring cooler 15 to increase the temperature of the waste flue gas, and then it is discharged through the air outlet of the ring cooler 15. The waste flue gas discharged from the air outlet of the ring cooler 15 is further dusted and purified by the fourth dust collector 29 under the suction action of the induced draft fan 28; then enter the denitrification system 30 for NO x The high-temperature denitrification process is then subjected to removal treatment to achieve energy saving and consumption reduction in the high-temperature denitrification process; finally, the gas is discharged into the atmosphere through the chimney 31 to achieve standard emission.

[0039] The treatment method of the present invention utilizes the first circulation fan 13 to extract the waste flue gas generated by the low-temperature section of the sintering machine to participate in the flue gas circulation, and controls the flow rate of the circulating flue gas in the first flue gas treatment loop 7 through the first regulating valve 9. The circulating flue gas rich in CO collected by the wind box of the low-temperature section of the sintering machine passes through the flue hood 2 through the first flue gas treatment loop 7 and enters the combustion zone of the high-temperature section 5 of the sintering machine to participate in the combustion, and the CO in the circulating flue gas is oxidized to CO2, thereby reducing the concentration of CO contained in the exhaust flue gas.

[0040] The treatment method of the present invention utilizes the second circulation fan 14 to extract the waste flue gas generated by the high temperature section of the sintering machine to participate in the flue gas circulation, and controls the flow rate of the circulating flue gas in the second flue gas treatment loop 8 through the second regulating valve 10. The recirculated flue gas collected by the wind box of the high temperature section 5 of the sintering machine passes through the flue gas hood 2 through the second flue gas treatment loop 8, enters the combustion zone of the low temperature section 4 of the sintering machine to participate in the combustion, and provides heat energy for the low temperature section 4, thereby reducing the heat energy consumption of the sintering system.

[0041] The treatment method of the present invention utilizes the main exhaust fan 20 to extract the waste flue gas generated by other sections of the sintering machine. After the dust removal treatment in the third dust collector 17 and the desulfurization treatment in the desulfurization system 27, the waste flue gas enters the ring cooler 15 through the front section 6 of the loop, and undergoes heat exchange treatment and partial oxidation-reduction reaction with the high-temperature sintered ore passing through the ring cooler 15, thereby increasing the temperature of the waste flue gas. The waste flue gas then enters the denitrification system 30, thereby achieving energy saving and consumption reduction in the high-temperature denitrification link; at the same time, the CO contained in the flue gas is oxidized to CO2, thereby further reducing the CO in the exhaust gas and reducing the blast furnace coke ratio of the next process.

[0042] In order to ensure the full combustion and low emission of CO, the treatment method of the present invention realizes dynamic adjustment of the opening of the pipeline valves in the three treatment loops according to the temperature and flow rate of the circulating flue gas detected by the three detector groups at different parts of the system and the concentration of oxygen and CO contained therein. By monitoring and regulating the flow rate, temperature and concentration of oxygen and CO contained in the circulating flue gas in the first flue gas treatment loop 7, the second flue gas treatment loop 8 and the main flue gas treatment loop, and by monitoring and regulating the oxygen content in the circulating flue gas entering the high-temperature section and the low-temperature section of the sintering machine, the proportion of the flue gas extracted from the low-temperature section and the high-temperature section entering the main flue gas treatment loop, the first flue gas treatment loop and the second flue gas treatment loop can be adjusted, so that the concentration of CO contained in the flue gas discharged through the main flue gas treatment loop can be maintained at 2500mg / m 3 As a result, precise control of CO emissions from sintering flue gas is achieved, achieving standard emissions.

Claims

1. A sintering flue gas treatment system for reducing CO emissions, characterized in that: include: The first flue gas treatment loop has one end connected to a plurality of wind boxes arranged below the low-temperature section of the sintering machine, and the other end penetrates the sintering machine flue gas hood and enters the combustion area of ​​the high-temperature section of the sintering machine; the first regulating valve, the first dust collector, the first circulating fan and the first fresh air supply pipe are respectively connected in the treatment loop, and the first fresh air supply pipe is connected to the air supply valve; a first detector group, arranged in the first flue gas treatment circuit, including a temperature detector, a flow detector, an oxygen detector and a CO detector, for detecting the temperature and flow of the waste flue gas entering the first flue gas treatment circuit and the concentration of oxygen and CO contained in the waste flue gas, and sending detection information to the controller; The second flue gas treatment loop has one end connected to a plurality of wind boxes arranged below the high-temperature section of the sintering machine, and the other end penetrates the sintering machine fume hood and enters the combustion area of ​​the low-temperature section of the sintering machine; the second regulating valve, the second dust collector, the second circulating fan and the second fresh air supply pipe are respectively connected in the treatment loop, and the second fresh air supply pipe is connected to the air supply valve; A second detector group, arranged in the second flue gas treatment circuit, includes a temperature detector, a flow detector, an oxygen detector and a CO detector, and is used to detect the temperature and flow of the waste flue gas entering the second flue gas treatment circuit and the concentration of oxygen and CO contained in the waste flue gas, and send detection information to the controller; as well as The controller is electrically connected to the first regulating valve, the second regulating valve, the air supply valves on the two fresh air supply pipes, the detectors in the first detector group and the detectors in the second detector group respectively; the controller is used to receive the detection information sent by each detector, and perform at least the following three controls according to the detection information and process requirements: first, control the flue gas flow rate of the first flue gas treatment circuit to circulate the waste flue gas extracted from the low-temperature section of the sintering machine to the combustion zone of the high-temperature section of the sintering machine; second, control the flue gas flow rate of the second flue gas treatment circuit to circulate the waste flue gas extracted from the high-temperature section of the sintering machine to the combustion zone of the low-temperature section of the sintering machine; third, control the air supplement amount of the first fresh air supply pipe and the second fresh air supply pipe to adjust the oxygen content in the two circulating flue gases to ensure normal combustion in the combustion zone of the sintering machine.

2. The sintering flue gas treatment system for reducing CO emissions according to claim 1 is characterized in that: include: The main flue gas treatment loop includes a front section and a rear section; one end of the front section is connected to the other wind boxes in the sintering machine that participate in the above two flue gas cycles, and the other end is connected to the air inlet of the cooling section of the ring cooler; the main exhaust fan, the third dust collector and the desulfurization system are respectively connected in the front section of the loop; the rear section of the loop is connected from the air outlet of the ring cooler to the chimney, and the fourth dust collector, the denitrification system and the induced draft fan are respectively connected in the rear section of the loop; as well as The third detector group is arranged in the front section of the loop, and includes a temperature detector, a flow detector, an oxygen detector and a CO detector which are electrically connected to the controller respectively, and is used to detect the temperature and flow of the waste flue gas entering the main flue gas treatment loop and the concentration of oxygen and CO contained in the waste flue gas, and send the detection information to the controller.

3. The sintering flue gas treatment system for reducing CO emissions according to claim 1 or 2, characterized in that: A first oxygen content detector electrically connected to the controller is connected in the first flue gas treatment circuit to send detection information of oxygen concentration in the waste flue gas introduced into the high-temperature section of the sintering machine to the controller. The controller controls the opening and closing and the opening size of the air supply valve on the first fresh air supply pipe accordingly, so that the oxygen concentration in the circulating flue gas is not less than 18%.

4. The sintering flue gas treatment system for reducing CO emissions according to claim 1 or 2, characterized in that: A second oxygen content detector electrically connected to the controller is connected in the second flue gas treatment circuit to send the detection information of the oxygen concentration in the waste flue gas introduced into the low-temperature section of the sintering machine to the controller. The controller controls the opening and closing and the opening size of the air supply valve on the second fresh air supply pipe accordingly, so that the oxygen concentration in the circulating flue gas is not less than 18%.

5. A sintering flue gas treatment method for reducing CO emissions, characterized in that: The following steps are involved: S1. Arrange a sintering fume treatment system as described in any one of claims 1 to 4; S2. The first circulation fan in the first flue gas treatment circuit is used to extract the waste flue gas from the low-temperature section of the sintering machine to participate in the flue gas circulation. After the waste flue gas is dust-removed and purified by the first dust collector, it enters the combustion zone of the high-temperature section of the sintering machine to participate in combustion, so that the CO contained therein is oxidized to CO2; S3. The second circulation fan in the second flue gas treatment circuit is used to extract the waste flue gas from the high-temperature section of the sintering machine to participate in the flue gas circulation. After the waste flue gas is purified by the second dust collector, it enters the combustion zone of the low-temperature section of the sintering machine to participate in combustion, providing high-temperature heat for the low-temperature section.

6. The sintering flue gas treatment method for reducing CO emissions according to claim 5 is characterized in that: The following steps are also included: S4. Use the main exhaust fan in the main flue gas treatment circuit to extract the waste flue gas from other wind boxes in the sintering machine that are not involved in the flue gas circulation and treat it as follows: first pass through the third dust collector for dust removal and purification, then pass through the desulfurization system for SO2 removal, and then enter the ring cooler, in the cooling section of the ring cooler, heat exchange and oxidation-reduction reaction are carried out with the high-temperature sintered ore entering the ring cooler. The waste flue gas discharged from the air outlet of the ring cooler is first passed through the fourth dust collector for dust removal and purification under the suction action of the induced draft fan, and then enters the denitrification system for NO x is removed and finally discharged into the atmosphere through the chimney.

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