System and method for eliminating secondary combustion of carbon monoxide in sintering flue gas

Abstract

The invention provides a secondary combustion elimination system and method for carbon monoxide in sintering flue gas, the system comprises a combustion tube and a cooling tower, two ends of the combustion tube are respectively provided with a flue gas inlet and a flue gas outlet, the flue gas inlet of the combustion tube is connected with a sintering machine, and a plurality of nozzles are arranged on the combustion tube at intervals along the circumferential direction of the combustion tube. Air outlets of the multiple nozzles extend into the combustion pipe, and air inlets of the multiple nozzles are located outside the combustion pipe and connected with a coal gas supply pipeline and an oxygen-enriched air supply pipeline correspondingly, so that coal gas and oxygen-enriched air are sprayed into the combustion pipe through the multiple nozzles correspondingly; a smoke outlet of the combustion pipe is connected with the cooling tower, and the cooling tower is used for cooling smoke generated after combustion in the combustion pipe. Even under the condition that the concentration of carbon monoxide in sintering flue gas fluctuates greatly, stable secondary combustion can still be achieved, and it is guaranteed that carbon monoxide in the flue gas is fully eliminated.

Description

Technical Field

[0001] This invention relates to the field of sintering flue gas treatment technology, and in particular to a system and method for eliminating secondary combustion of carbon monoxide in sintering flue gas. Background Technology

[0002] As a vital pillar industry of the economy, the steel industry plays an irreplaceable role in numerous fields such as infrastructure construction, machinery manufacturing, automobile industry, and shipbuilding, and is a key force driving industrialization and modernization. The sintering process, as one of the important technological units in steel production, is a major source of pollutants. During sintering, sintering flue gas containing a large amount of pollutants is generated, mainly including sulfur dioxide, nitrogen oxides, carbon monoxide, carbon dioxide, particulate matter, dioxins, and heavy metals. Incomplete combustion of carbon releases carbon monoxide gas, with the sintering process accounting for approximately 22% of the total carbon monoxide emissions from steel enterprises. The initial carbon monoxide concentration in the sintering process can reach 8000-10000 mg / m³, far exceeding the combined emissions of sulfur dioxide, nitrogen oxides, and other pollutants. Therefore, its control has become a key concern for steel enterprises.

[0003] Carbon monoxide, a toxic gas, is colorless and odorless, and can persist in the air for extended periods. When inhaled, it binds to hemoglobin in the blood to form carboxyhemoglobin, reducing the oxygen-carrying capacity of hemoglobin and damaging the heart, brain, and respiratory system, severely endangering human health. Prolonged exposure to low levels of carbon monoxide can easily lead to anemia, indigestion, difficulty breathing, visual or hearing impairment, and intellectual decline. Furthermore, carbon monoxide reacts photochemically with non-methane hydrocarbons (NMHC) and nitrogen oxides (NOx) in the atmosphere, causing photochemical pollution, and reacts with ozone, reducing atmospheric ozone levels and causing serious environmental damage.

[0004] Currently, the methods for eliminating carbon monoxide generally include the following: ① Process control method: By increasing the average particle size of coke powder to improve the permeability of the material bed, the sintering material is fully combusted while improving the quality of the sintered product, thus reducing carbon monoxide emissions. However, this process requires high operational skills and has very limited effect on reducing carbon monoxide content; ② Circulating flue gas method: Using a flue gas recirculation system to selectively treat flue gas in stages can reduce the carbon monoxide content in sintering flue gas. However, this process can only reduce the carbon monoxide emission concentration by 20-30%, and the amount of carbon monoxide in the flue gas remains relatively high. The carbon monoxide content is still higher than 6000 mg / Nm³, and it will affect production efficiency, so the actual use effect is not ideal; ③ Catalytic method, which uses a catalyst to catalytically burn carbon monoxide in flue gas. This method can reduce carbon monoxide emissions, but the catalyst has high production cost, short life, and strict requirements on flue gas conditions, resulting in poor economic efficiency; ④ High-temperature combustion method, which heats all sintering flue gas to above 800℃ to oxidize all carbon monoxide into carbon dioxide, but this process has the disadvantages of high investment cost, complex system, and low energy utilization rate.

[0005] In summary, existing carbon monoxide treatment technologies in steel sintering flue gas urgently need improvement to address issues such as poor combustion stability and short equipment lifespan, in order to meet increasingly stringent environmental protection requirements and the actual needs of steel production.

[0006] Therefore, this invention proposes a system and method for eliminating secondary combustion of carbon monoxide in sintering flue gas, in order to overcome the deficiencies of the prior art. Summary of the Invention

[0007] The purpose of this invention is to provide a secondary combustion elimination system for carbon monoxide in sintering flue gas, which can still achieve stable secondary combustion even when the carbon monoxide concentration in the sintering flue gas flues significantly, thus ensuring the complete elimination of carbon monoxide in the flue gas.

[0008] The purpose of this invention is to provide a method for eliminating secondary combustion of carbon monoxide in sintering flue gas. Through the synergistic effect of a multi-level interlocking mechanism, it can promptly detect and take measures when the combustion temperature is too high or the oxygen content is abnormal. It is applicable to the treatment of sintering flue gas under different working conditions, with better mobility and flexibility, ensuring the safety of the production process and reducing the potential harm to the environment and human health caused by secondary pollutants due to sudden failures.

[0009] The objective of this invention can be achieved through the following methods:

[0010] This invention provides a secondary combustion elimination system for carbon monoxide in sintering flue gas, comprising a combustion tube and a cooling tower. The combustion tube has a flue gas inlet and a flue gas outlet at its two ends. The flue gas inlet of the combustion tube is connected to a sintering machine. Multiple nozzles are arranged at intervals along the circumference of the combustion tube. The outlets of the multiple nozzles extend into the combustion tube, and the inlets of the multiple nozzles are located outside the combustion tube and are respectively connected to a coal gas supply pipeline and an oxygen-enriched air supply pipeline, so as to inject coal gas and oxygen-enriched air into the combustion tube through the multiple nozzles respectively.

[0011] The flue gas outlet of the combustion tube is connected to the cooling tower, which is used to cool the flue gas after combustion in the combustion tube.

[0012] In a preferred embodiment of the present invention, a plurality of first guide plates are provided in the combustion tube and downstream of the nozzle along the flow direction of the flue gas inside the combustion tube. One end of the plurality of first guide plates is rotatably disposed on the inner wall of the combustion tube, and the other end of the plurality of first guide plates extends toward the axis of the combustion tube. By rotating the first guide plates, the angle between the first guide plates and the axis of the combustion tube can be adjusted.

[0013] In a preferred embodiment of the present invention, a plurality of nozzles and a plurality of first guide vanes are arranged alternately along the circumference of the combustion tube.

[0014] In a preferred embodiment of the present invention, a plurality of second guide plates are provided inside the combustion tube near the flue gas inlet. One end of the plurality of second guide plates is rotatably disposed on the inner wall of the combustion tube, and the other end of the plurality of second guide plates extends toward the axis of the combustion tube. By rotating the second guide plates, the angle between the second guide plates and the axis of the combustion tube can be adjusted.

[0015] In a preferred embodiment of the present invention, there are multiple flue gas inlets, and along the circumference of the combustion tube, the multiple flue gas inlets respectively correspond to the space between two adjacent second guide plates.

[0016] In a preferred embodiment of the present invention, the carbon monoxide secondary combustion elimination system in the sintering flue gas further includes a controller, a vibration monitoring element is provided on the combustion tube, an oxygen monitoring element is provided inside the combustion tube near the flue gas outlet, an infrared thermometer is provided outside the combustion tube, and the monitoring signal output terminals of the vibration monitoring element, the oxygen monitoring element, and the infrared thermometer are electrically connected to the signal receiving terminal of the controller.

[0017] In a preferred embodiment of the present invention, the air inlet of the nozzle is connected to an air inlet pipe, and a valve element and a blower are provided on the air inlet pipe. The control signal output terminal of the controller is electrically connected to the control terminal of the valve element and the control terminal of the blower, respectively.

[0018] In a preferred embodiment of the present invention, the carbon monoxide secondary combustion elimination system in the sintering flue gas further includes a desulfurization and denitrification device, and the outlet of the cooling tower is connected to the inlet of the desulfurization and denitrification device.

[0019] In a preferred embodiment of the present invention, a waste heat boiler is provided between the flue gas outlet of the combustion tube and the cooling tower, and the heat in the flue gas is recovered to the waste heat boiler by means of heat exchange.

[0020] This invention provides a method for eliminating secondary combustion of carbon monoxide in sintering flue gas, which is implemented using the aforementioned system for eliminating secondary combustion of carbon monoxide in sintering flue gas. The method for eliminating secondary combustion of carbon monoxide in sintering flue gas includes the following steps:

[0021] Step S1: The raw flue gas generated by the sintering machine is delivered to the combustion tube;

[0022] Step S2: Gas and oxygen-enriched air are introduced into the combustion tube through a nozzle so that the carbon monoxide in the original flue gas is burned in the combustion tube to generate carbon dioxide.

[0023] Step S3: The flue gas after combustion in the combustion tube is transported to the cooling tower for rapid cooling;

[0024] Step S4: Perform desulfurization and denitrification treatment on the flue gas after rapid cooling.

[0025] In a preferred embodiment of the present invention, the preset combustion temperature in the combustion tube is 800°C to 1100°C.

[0026] In a preferred embodiment of the present invention, in step S2, the combustion temperature inside the combustion tube is monitored in real time by an infrared temperature measuring element; when the actual combustion temperature inside the combustion tube exceeds the preset combustion temperature, the opening of the valve element is controlled by the controller to adjust the supply of gas and / or oxygen-enriched air.

[0027] In a preferred embodiment of the present invention, in step S2,

[0028] When the actual combustion temperature inside the combustion tube exceeds 1150°C, the supply of coal gas and oxygen-enriched air is stopped, and nitrogen is supplied into the combustion tube.

[0029] And / or, when the oxygen content in the flue gas at the flue gas outlet of the combustion tube exceeds 6%, the gas supply to part of the nozzle is stopped.

[0030] In a preferred embodiment of the present invention, between step S3 and step S4, heat in the flue gas is recovered to the waste heat boiler through heat exchange.

[0031] Based on the above, the characteristics and advantages of the carbon monoxide secondary combustion elimination system and method in sintering flue gas of the present invention are as follows:

[0032] A combustion tube is directly connected to the flue gas outlet of the sintering machine. Multiple nozzles are spaced along the circumference of the combustion tube, through which coal gas and oxygen-enriched air are injected into the combustion tube respectively. The carbon monoxide in the flue gas is burned by the igniter in the combustion tube. After the carbon monoxide in the flue gas is converted into carbon dioxide, subsequent desulfurization and denitrification treatments are carried out. The combustion tube realizes the pretreatment of carbon monoxide in the flue gas. Even if there are large fluctuations in the carbon monoxide concentration in the sintering flue gas, stable secondary combustion of carbon monoxide can still be achieved by controlling the supply of coal gas and / or oxygen-enriched air into the combustion tube. This ensures the complete elimination of carbon monoxide in the flue gas and effectively solves the problems of poor combustion stability and short equipment life caused by large fluctuations in the carbon monoxide concentration in steel sintering flue gas. Attached Figure Description

[0033] The following figures are intended only to illustrate and explain the present invention and do not limit the scope of the invention. Wherein:

[0034] Figure 1 This is a schematic diagram of the carbon monoxide secondary combustion elimination system in the sintering flue gas of the present invention;

[0035] Figure 2 This is a schematic diagram of the internal structure of the combustion tube in the carbon monoxide secondary combustion elimination system in the sintering flue gas of the present invention.

[0036] Figure 3 This is a schematic diagram of the end structure of the combustion tube in the carbon monoxide secondary combustion elimination system in the sintering flue gas of the present invention.

[0037] Figure 4 This is a flowchart of the method for eliminating secondary combustion of carbon monoxide in sintering flue gas according to the present invention.

[0038] The reference numerals in the accompanying drawings of this invention are:

[0039] 1. Combustion tube; 101. Flue gas inlet; 2. Second guide vane; 3. First guide vane; 4. Nozzle; 5. Sintering machine; 6. Main flue; 7. Cooling tower; 8. Desulfurization and denitrification equipment; 9. Humidity monitoring element; 10. Controller; 11. Vibration monitoring element; 12. Oxygen monitoring element; 13. Blower; 14. Valve element; 15. Waste heat boiler. Detailed Implementation

[0040] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0041] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0043] Implementation Method 1

[0044] like Figures 1 to 3 As shown, the present invention provides a secondary combustion elimination system for carbon monoxide in sintering flue gas. The system includes a combustion tube 1 and a cooling tower 7. One end of the combustion tube 1 has a flue gas inlet 101, and the other end has a flue gas outlet. The flue gas inlet 101 of the combustion tube 1 is directly connected to the flue gas outlet of the sintering machine 5 through the main flue 6. Multiple nozzles 4 are arranged at intervals along the circumference of the combustion tube 1. The outlets of the multiple nozzles 4 extend into the combustion tube 1, and the inlets of the multiple nozzles 4 are located outside the combustion tube 1. The inlets of the multiple nozzles 4 are connected to a coal gas supply pipeline and an oxygen-enriched air supply pipeline, respectively, so as to inject coal gas and oxygen-enriched air into the combustion tube 1 through the multiple nozzles 4. The flue gas outlet of the combustion tube 1 is connected to the inlet of the cooling tower 7, which is used to cool the flue gas after combustion in the combustion tube 1.

[0045] In this invention, a combustion pipe 1 is directly connected to the flue gas outlet of the sintering machine 5. Multiple nozzles 4 are arranged circumferentially on the combustion pipe 1, through which coal gas and oxygen-enriched air are injected into the combustion pipe 1 respectively. The carbon monoxide in the flue gas is ignited and burned by the igniter in the combustion pipe 1. After the carbon monoxide in the flue gas is converted into carbon dioxide, subsequent desulfurization and denitrification treatments are carried out. The setting of the combustion pipe 1 realizes the pretreatment of carbon monoxide in the flue gas. Even if there is a large fluctuation in the carbon monoxide concentration in the sintering flue gas, stable secondary combustion of carbon monoxide can still be achieved by controlling the supply of coal gas and / or oxygen-enriched air into the combustion pipe 1, thereby ensuring the complete elimination of carbon monoxide in the flue gas. This effectively solves the problems of poor combustion stability and short equipment life caused by large fluctuations in the carbon monoxide concentration in the steel sintering flue gas.

[0046] In an optional embodiment of the present invention, such as Figure 1 and Figure 2 As shown, along the flow direction of the flue gas in the combustion tube 1, a plurality of first guide plates 3 are arranged in the combustion tube 1 and downstream of the nozzle 4. One end of the plurality of first guide plates 3 is rotatably disposed on the inner wall of the combustion tube 1, and the other end of the plurality of first guide plates 3 extends toward the axis of the combustion tube 1. By rotating the first guide plates 3, the angle between the first guide plates 3 and the axis of the combustion tube 1 can be adjusted, thereby changing the flow direction of the flue gas, coal gas and oxygen-enriched air in the combustion tube 1, so as to ensure that the flue gas, coal gas and oxygen-enriched air are mixed more evenly in the combustion tube 1, thereby enabling the complete combustion and elimination of carbon monoxide downstream of the first guide plates 3.

[0047] The angle between the first guide vane 3 and the axis of the combustion tube 1 can be, but is not limited to, 25° to 35°.

[0048] Furthermore, such as Figure 2 As shown, multiple nozzles 4 and multiple first guide plates 3 are arranged alternately along the circumference of the combustion tube 1. This allows the gas and oxygen-enriched air injected into the combustion tube 1 through each nozzle 4 to impact the surface of the first guide plates 3 along the flow direction, thereby disrupting the original flow field of the gas and oxygen-enriched air and forming a turbulent field near the first guide plates 3. This promotes the mixing of carbon monoxide in the flue gas with the gas and oxygen-enriched air, providing a favorable flow field basis for the subsequent efficient combustion reaction. The first guide plates 3 can be mounted on the inner wall of the combustion tube 1 via a rotating shaft. Of course, other rotating structures can also be used to install the first guide plates 3; no specific limitation is made here.

[0049] Among them, the nozzle 4 can be made of composite corrosion-resistant refractory material (such as 310S heat-resistant steel), and the temperature limit of the nozzle 4 can reach 1300℃; the inner wall of the nozzle 4 can be sprayed with a heat insulation coating, and the surface of the nozzle 4 can be covered with a silicon carbide ceramic layer, thereby achieving corrosion resistance.

[0050] In an optional embodiment of the present invention, such as Figure 1 As shown, multiple second guide plates 2 are installed inside the combustion tube 1 near the flue gas inlet 101. The second guide plates 2 have the same structure as the first guide plate 3. One end of each second guide plate 2 is rotatably mounted on the inner wall of the combustion tube 1, and the other end extends towards the axis of the combustion tube 1. By rotating the second guide plates 2, the angle between the second guide plates 2 and the axis of the combustion tube 1 can be adjusted. The second guide plates 2 help to mix the flue gas initially entering the combustion tube 1, thereby ensuring that carbon monoxide in the flue gas is evenly distributed.

[0051] The angle between the second guide vane 2 and the axis of the combustion tube 1 can be, but is not limited to, 25° to 35°.

[0052] Furthermore, such as Figure 3 As shown, there are multiple flue gas inlets 101 along the circumference of the combustion tube 1, each corresponding to the space between two adjacent second guide plates 2. This allows the original flue gas entering the combustion tube 1 through the flue gas inlets 101 to mix under the backflow effect of the adjacent second guide plates 2, thereby disrupting the original flow field of the flue gas and forming a turbulent field near the second guide plates 2. This promotes the homogenization of carbon monoxide in the flue gas and provides a favorable flow field basis for the subsequent efficient combustion reaction. The second guide plates 2 can be mounted on the inner wall of the combustion tube 1 via a rotating shaft. Of course, other rotating structures can also be used to install the second guide plates 2; no specific limitation is made here.

[0053] In an optional embodiment of the present invention, such as Figure 1 As shown, the carbon monoxide secondary combustion elimination system in sintering flue gas also includes a controller 10. A vibration monitoring element 11 is installed on the combustion tube 1, and an oxygen monitoring element 12 is installed inside the combustion tube 1 near the flue gas outlet. An infrared thermometer (not shown) is installed outside the combustion tube 1. The monitoring signal output terminals of the vibration monitoring element 11, the oxygen monitoring element 12, and the infrared thermometer are electrically connected to the signal receiving terminal of the controller 10. During actual operation, the vibration monitoring element 11 monitors the guide plates (first guide plate 3 and / or second guide plate 2) to ensure stable airflow within the combustion tube 1. Simultaneously, the oxygen monitoring element 12 monitors the oxygen content at the flue gas outlet of the combustion tube 1 to prevent excessive oxygen intake. The infrared thermometer monitors the stability within the combustion tube 1 to ensure that the temperature within the combustion tube 1 remains within the preset combustion temperature range.

[0054] Among them, the controller 10 may be, but is not limited to, a PID controller, the oxygen monitoring element 12 may be, but is not limited to, an oxygen meter, and the infrared temperature measuring element may be, but is not limited to, a dual-wavelength infrared thermometer.

[0055] The vibration monitoring element 11 can be, but is not limited to, a piezoelectric vibration sensor. When the vibration acceleration detected by the vibration monitoring element 11 is greater than or equal to 5g, the controller 10 automatically triggers an alarm signal and links to limit the opening of the valve element 14 and / or adjust the jet rate and time of different nozzles 4, and the gas injection rhythm to prevent the accumulation of local high-frequency resonance from causing blade fatigue failure.

[0056] In an optional embodiment of the present invention, such as Figure 1 As shown, the air inlet of nozzle 4 is connected to an air inlet pipe, on which a valve element 14 and a blower 13 are installed. The control signal output terminal of controller 10 is electrically connected to the control terminal of valve element 14 and the control terminal of blower 13, respectively. The amount of gas and oxygen-enriched air entering combustion pipe 1 can be adjusted in real time by controlling the opening degree of valve element 14 and the working state of blower 13.

[0057] In an optional embodiment of the present invention, the angle between the axial direction of the outlet of the nozzle 4 and the flow direction of the flue gas in the combustion tube 1 may be, but is not limited to, 20° to 30°.

[0058] In an optional embodiment of the present invention, such as Figure 1 As shown, the carbon monoxide secondary combustion elimination system in sintering flue gas also includes a desulfurization and denitrification device 8. The outlet of the cooling tower 7 is connected to the inlet of the desulfurization and denitrification device 8. After the flue gas is rapidly cooled by the cooling tower 7, the rapidly cooled flue gas enters the desulfurization and denitrification device 8 for further purification treatment and is discharged after meeting the standards.

[0059] In an optional embodiment of the present invention, such as Figure 1 As shown, a humidity monitoring element 9 is provided inside the cooling tower 7 to monitor the humidity of the flue gas inside the cooling tower 7 in real time. The humidity monitoring element 9 may be, but is not limited to, a humidity sensor.

[0060] In an optional embodiment of the present invention, such as Figure 1 As shown, a waste heat boiler 15 is installed between the flue gas outlet of the combustion tube 1 and the cooling tower 7. The waste heat boiler 15 is equipped with heat exchange tubes, which can be inserted into the flue gas conveying pipeline between the flue gas outlet of the combustion tube 1 and the cooling tower 7. The heat in the flue gas is recovered to the waste heat boiler 15 through heat exchange, ensuring full utilization of the heat in the flue gas.

[0061] The features and advantages of the carbon monoxide secondary combustion elimination system in sintering flue gas of the present invention are as follows:

[0062] This secondary combustion elimination system for carbon monoxide in sintering flue gas can pre-treat carbon monoxide in the flue gas through the setting of combustion pipe 1. Even when there are large fluctuations in the carbon monoxide concentration in the sintering flue gas, stable secondary combustion of carbon monoxide can still be achieved by controlling the supply of coal gas and / or oxygen-enriched air to combustion pipe 1, thereby ensuring the full elimination of carbon monoxide in the flue gas. This effectively solves the problems of poor combustion stability and short equipment life caused by large fluctuations in the carbon monoxide concentration in steel sintering flue gas.

[0063] Implementation Method 2

[0064] like Figure 4 As shown, the present invention provides a method for eliminating secondary combustion of carbon monoxide in sintering flue gas, which is implemented using the above-mentioned system for eliminating secondary combustion of carbon monoxide in sintering flue gas. The method for eliminating secondary combustion of carbon monoxide in sintering flue gas includes the following steps:

[0065] Step S1: The raw flue gas generated by the sintering machine 5 is delivered to the combustion tube 1;

[0066] Step S2: Gas and oxygen-enriched air are introduced into the combustion tube 1 through nozzle 4 so that the carbon monoxide in the original flue gas is burned in the combustion tube 1 to generate carbon dioxide.

[0067] Step S3: The flue gas after combustion in the combustion tube 1 is transported to the cooling tower 7 for rapid cooling; wherein, the preset combustion temperature in the combustion tube 1 needs to be between 800℃ and 1100℃, that is, during the operation, the combustion temperature in the combustion tube 1 is maintained between 800℃ and 1100℃.

[0068] Step S4: Perform desulfurization and denitrification treatment on the flue gas after rapid cooling.

[0069] In an optional embodiment of the present invention, the number of nozzles 4 can be eight, and the eight nozzles 4 are evenly distributed along the circumference of the combustion tube 1. The angle between the axial direction of the outlet of the nozzle 4 and the flow direction of the flue gas in the combustion tube 1 can be, but is not limited to, 20° to 30°. The injection pressure of the outlet of the nozzle 4 can be, but is not limited to, 0.4 to 0.6 MPa, and the injection velocity of the outlet of the nozzle 4 can be, but is not limited to, 90 to 110 m / s. With the above configuration, the coal gas and oxygen-enriched air can be rapidly and uniformly distributed in the high-temperature turbulent field and fully contact and react with carbon monoxide in the flue gas, thereby achieving the purpose of enhancing the secondary combustion efficiency of carbon monoxide.

[0070] In an optional embodiment of the present invention, in step S2, the combustion temperature inside the combustion tube 1 is monitored in real time by an infrared temperature measuring element; when the actual combustion temperature inside the combustion tube 1 exceeds the preset combustion temperature, the opening of the valve element 14 is controlled by the controller 10 to adjust the supply of coal gas and / or oxygen-enriched air. To further stabilize the flame and ensure combustion integrity, combustion air is provided, and the oxygen concentration in the oxygen-enriched air can be, but is not limited to, 28%-32%, and the dust concentration inside the combustion tube 1 is ensured to be less than or equal to 1500 mg / Nm³, so as to ensure stable combustion of the flame, ensure that carbon monoxide in the flue gas is fully converted into carbon dioxide, and provide suitable flue gas composition and temperature conditions for the subsequent rapid cooling and purification system.

[0071] In an optional embodiment of the present invention, in step S2, when the actual combustion temperature in the combustion tube 1 exceeds 1150°C, the supply of coal gas and oxygen-enriched air is stopped, and nitrogen is supplied to the combustion tube 1; and / or, when the oxygen content in the flue gas at the flue gas outlet of the combustion tube 1 exceeds 6%, the gas supply from some nozzles 4 is stopped.

[0072] In this invention, to ensure the efficient secondary combustion of carbon monoxide under optimal thermodynamic conditions, a dual-wavelength infrared thermometer is used to monitor the actual combustion temperature of the combustion zone within the combustion tube 1 online. This thermometer can measure the temperature of the core flame region online at a frequency of more than 10 times per second. When the actual combustion temperature deviates from the preset combustion temperature range, the controller 10 immediately activates the PID algorithm to dynamically adjust the opening of the valve element 14 (response time ≤ 0.5s). This mechanism ensures the stability of the combustion reaction within the combustion tube 1 and the full oxidation and conversion of carbon monoxide, avoiding carbon monoxide residue or heat loss due to temperature fluctuations. The specific parameters of the PID algorithm can be adjusted according to actual operating conditions. The proportional coefficient (P) is generally between 0.5 and 1.5, the integral time (I) is generally between 10 and 30s, and the derivative time (D) is generally between 0.1 and 0.5s. The adjustment is based on monitoring and analyzing temperature fluctuations during combustion, continuously optimizing the parameters to enable the system to respond quickly and stably to temperature changes.

[0073] In addition, in this invention, the residual oxygen content in the flue gas at the flue gas outlet of the combustion tube 1 is monitored in real time by a zirconia oxygen meter. The oxygen-enriched air is adjusted according to the residual oxygen content of 3.5% to 4.5%. By increasing the speed of the blower 13, the full combustion of carbon monoxide in the combustion tube 1 is ensured, so as to achieve the purpose of energy efficiency optimization. At the same time, heat loss caused by excess oxygen or incomplete combustion caused by insufficient oxygen is avoided, thereby achieving a high-efficiency, low-carbon, and low-pollution carbon monoxide elimination effect.

[0074] In this invention, to ensure the safe and stable operation of the combustion process, when the actual combustion temperature in the combustion zone of the combustion tube 1 exceeds 1150°C, the controller 10 urgently cuts off the gas supply (closes valve element 14) and injects nitrogen for inerting, thereby suppressing the continued combustion reaction. This measure prevents a sharp rise in temperature caused by local anomalies in the combustion tube 1, thus avoiding the ablation of nozzle 4 or the generation of secondary pollutants in the flue gas. When the oxygen content at the flue gas outlet of the combustion tube 1 exceeds 6%, the controller 10 immediately forces the closure of half of the currently operating nozzles 4 (controlling the corresponding valve element 14 to close), thereby reducing the participation of combustion-supporting gases in the reaction. At the same time, an audible and visual alarm is activated to prompt the operator to intervene and check in time. This series of interlocking actions can quickly suppress the decrease in thermal efficiency, the increase in nitrogen oxide emissions, and the risk of local flameout caused by excessive air while maintaining the minimum combustion maintenance amount, ensuring stable combustion of the system and that environmental emission indicators are not compromised.

[0075] In an optional embodiment of the present invention, in step S3 above, during the rapid cooling process of the cooling tower 7, to achieve a rapid temperature reduction of the flue gas after high-temperature combustion, compressed air and coolant are mixed at high speed and atomized and sprayed into the cooling tower to form fine droplets, achieving efficient and rapid cooling. The coolant can be, but is not limited to, desalination wastewater from a sintering plant (pH=6.5-7.5, chloride ion concentration ≤200mg / L). The coolant has good neutral buffering properties to avoid corrosion of the inner wall of the cooling tower 7. To prevent excessive moisture during the cooling process from causing flue gas oversaturation and condensation on low-temperature surfaces, thus corroding downstream equipment, a humidity monitoring element 9 can be installed at the outlet of the cooling tower 7. When the relative humidity of the flue gas is greater than 90%, the controller 10 controls the amount of liquid sprayed into the cooling tower 7 to reduce condensation and corrosion of downstream equipment.

[0076] In an optional embodiment of the present invention, in step S4 above, the rapidly cooled flue gas enters the desulfurization and denitrification equipment 8. The desulfurization and denitrification equipment 8 (including a desulfurization tower and an SCR reactor) can employ limestone-gypsum desulfurization combined with selective catalytic reduction (SCR) denitrification. Inside the desulfurization tower, the flue gas comes into full contact with the sprayed limestone slurry, undergoing a chemical reaction to remove sulfur oxides from the flue gas. In the SCR reactor, ammonia is injected, and under the action of a catalyst, nitrogen oxides are reduced to nitrogen and water. During the desulfurization and denitrification process, the efficiency of the desulfurization and denitrification equipment 8 is periodically monitored, and the operating parameters are adjusted according to the monitoring results to ensure that the treated flue gas meets environmental emission standards.

[0077] In an optional embodiment of the present invention, between steps S3 and S4, heat from the flue gas is recovered to the waste heat boiler 15 via heat exchange. The high-temperature flue gas (typically between 800 and 1100 degrees Celsius) flows through this heat exchange zone before entering the cooling tower 7, providing a sufficient heat source for waste heat recovery. The heat exchange medium (condensate) absorbs the sensible heat of the flue gas during the counter-current heat exchange process, achieving a heat recovery efficiency greater than or equal to 15%, effectively reducing energy consumption costs.

[0078] The features and advantages of the method for eliminating secondary combustion of carbon monoxide in sintering flue gas according to the present invention are as follows:

[0079] I. Stable Combustion: Achieves stable secondary combustion to address significant fluctuations in carbon monoxide concentration in sintering flue gas (1000 to 15000 ppm). This addresses the harsh environment of high dust and corrosion in sintering flue gas, extending equipment lifespan and reducing maintenance costs. Furthermore, multi-stage interlocking control effectively prevents sudden temperature rises during flue gas treatment, reducing the risk of dioxin resynthesis, minimizing the generation of toxic and harmful substances, and protecting the environment and human health.

[0080] II. Flexible Adjustment: Under the synergistic effect of the multi-level interlocking mechanism, measures can be taken in a timely manner when the combustion temperature is too high or the oxygen content is abnormal. It is applicable to the treatment of sintering flue gas under different enterprises and different working conditions, and has the mobility and flexibility to ensure the safety of the production process and reduce the potential harm to the environment and human health caused by secondary pollutants generated in case of emergencies.

[0081] It should be noted that in the description of this application, the terms "first," "second," etc., are used only for descriptive purposes and to distinguish similar objects; there is no order between them, nor should they be construed as indicating or implying relative importance. Furthermore, in the description of this application, unless otherwise stated, "multiple" means two or more.

[0082] The various embodiments described in this specification are presented in a progressive manner. The same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

[0083] The above are merely a few embodiments of the present invention. Although the embodiments disclosed in the present invention are as described above, the content is only for the purpose of facilitating understanding of the present invention and is not intended to limit the present invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of the present invention should fall within the scope of protection of the present invention.

Claims

1. A system for eliminating secondary combustion of carbon monoxide in sintering flue gas, characterized in that, The device includes a combustion tube and a cooling tower. The combustion tube has a flue gas inlet and a flue gas outlet at both ends. The flue gas inlet of the combustion tube is connected to a sintering machine. Multiple nozzles are arranged at intervals along the circumference of the combustion tube. The outlets of the multiple nozzles extend into the combustion tube, and the inlets of the multiple nozzles are located outside the combustion tube and are respectively connected to a coal gas supply pipeline and an oxygen-enriched air supply pipeline, so as to inject coal gas and oxygen-enriched air into the combustion tube through the multiple nozzles. The flue gas outlet of the combustion tube is connected to the cooling tower, which is used to cool the flue gas after combustion in the combustion tube.

2. The carbon monoxide secondary combustion elimination system in sintering flue gas as described in claim 1, characterized in that, Along the flow direction of the flue gas inside the combustion tube, a plurality of first guide plates are provided inside the combustion tube and downstream of the nozzle. One end of the plurality of first guide plates is rotatably disposed on the inner wall of the combustion tube, and the other end of the plurality of first guide plates extends toward the axis of the combustion tube. By rotating the first guide plates, the angle between the first guide plates and the axis of the combustion tube can be adjusted.

3. The carbon monoxide secondary combustion elimination system in sintering flue gas as described in claim 2, characterized in that, The plurality of nozzles and the plurality of first guide vanes are arranged alternately along the circumference of the combustion tube.

4. The carbon monoxide secondary combustion elimination system in sintering flue gas as described in claim 2, characterized in that, A plurality of second guide plates are provided inside the combustion tube near the flue gas inlet. One end of each second guide plate is rotatably mounted on the inner wall of the combustion tube, and the other end of each second guide plate extends toward the axis of the combustion tube. By rotating the second guide plate, the angle between the second guide plate and the axis of the combustion tube can be adjusted.

5. The carbon monoxide secondary combustion elimination system in sintering flue gas as described in claim 4, characterized in that, There are multiple flue gas inlets, and along the circumference of the combustion tube, each of the multiple flue gas inlets corresponds to the space between two adjacent second guide plates.

6. The carbon monoxide secondary combustion elimination system in sintering flue gas as described in claim 1, characterized in that, The carbon monoxide secondary combustion elimination system in the sintering flue gas also includes a controller. A vibration monitoring element is installed on the combustion tube, an oxygen monitoring element is installed inside the combustion tube near the flue gas outlet, and an infrared thermometer is installed outside the combustion tube. The monitoring signal output terminals of the vibration monitoring element, the oxygen monitoring element, and the infrared thermometer are electrically connected to the signal receiving terminal of the controller.

7. The carbon monoxide secondary combustion elimination system in sintering flue gas as described in claim 6, characterized in that, The nozzle's air inlet is connected to an air inlet pipe, on which a valve element and a blower are installed. The controller's control signal output terminal is electrically connected to the control terminal of the valve element and the control terminal of the blower, respectively.

8. The carbon monoxide secondary combustion elimination system in sintering flue gas as described in claim 1, characterized in that, The carbon monoxide secondary combustion elimination system in the sintering flue gas also includes desulfurization and denitrification equipment, and the outlet of the cooling tower is connected to the inlet of the desulfurization and denitrification equipment.

9. The carbon monoxide secondary combustion elimination system in sintering flue gas as described in claim 1, characterized in that, A waste heat boiler is installed between the flue gas outlet of the combustion tube and the cooling tower, and the heat in the flue gas is recovered to the waste heat boiler through heat exchange.

10. A method for eliminating secondary combustion of carbon monoxide in sintering flue gas, comprising employing the carbon monoxide secondary combustion elimination system for sintering flue gas as described in any one of claims 1 to 9, characterized in that, The method for eliminating secondary combustion of carbon monoxide in sintering flue gas includes the following steps: Step S1: The raw flue gas generated by the sintering machine is delivered to the combustion tube; Step S2: Gas and oxygen-enriched air are introduced into the combustion tube through a nozzle so that the carbon monoxide in the original flue gas is burned in the combustion tube to generate carbon dioxide. Step S3: The flue gas after combustion in the combustion tube is transported to the cooling tower for rapid cooling; Step S4: Perform desulfurization and denitrification treatment on the flue gas after rapid cooling.

11. The method for eliminating secondary combustion of carbon monoxide in sintering flue gas as described in claim 10, characterized in that, The preset combustion temperature inside the combustion tube is 800°C to 1100°C.

12. The method for eliminating secondary combustion of carbon monoxide in sintering flue gas as described in claim 11, characterized in that, In step S2, the combustion temperature inside the combustion tube is monitored in real time by an infrared temperature measuring element; when the actual combustion temperature inside the combustion tube exceeds the preset combustion temperature, the opening of the valve element is controlled by the controller to adjust the supply of gas and / or oxygen-enriched air.

13. The method for eliminating secondary combustion of carbon monoxide in sintering flue gas as described in claim 12, characterized in that, In step S2 When the actual combustion temperature inside the combustion tube exceeds 1150°C, the supply of coal gas and oxygen-enriched air is stopped, and nitrogen is supplied into the combustion tube. And / or, when the oxygen content in the flue gas at the flue gas outlet of the combustion tube exceeds 6%, the gas supply to part of the nozzle is stopped.

14. The method for eliminating secondary combustion of carbon monoxide in sintering flue gas as described in claim 11, characterized in that, Between step S3 and step S4, heat from the flue gas is recovered to the waste heat boiler through heat exchange.

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