A sintering flue gas circulating system and method based on ring cooling waste gas characteristic matching

Abstract

The application provides a sintering flue gas circulating system and method based on ring cooling waste gas characteristic matching. The system comprises a sintering machine, an ignition heat preservation cover and a circulating flue gas cover arranged above the sintering machine, and a ring cooler, and further comprises: at least two ring cooling waste gas leading-out circuits, which are respectively connected with different segmented areas of the ring cooler, and can lead out ring cooling waste gas with different temperature and oxygen content combination characteristics; ring cooling waste gas injection circuits corresponding to the number of ring cooling waste gas leading-out circuits, which respectively directly transport the ring cooling waste gas led out by the ring cooling waste gas leading-out circuits to different injection areas above the sintering machine as process gas, and the injection areas at least include a first injection area arranged in the ignition heat preservation cover and a second injection area arranged in the head area of the circulating flue gas cover; a flow field regulating device, which comprises at least one guide vane assembly with an opening degree controlled by a driving module; and a control unit. The application realizes efficient utilization of ring cooling waste gas, optimization of the sintering process and improvement of the sinter quality.

Description

TECHNICAL FIELD

[0001] The present application relates to a sintering flue gas circulation system, in particular to a sintering flue gas circulation system and method based on characteristic matching of ring cooling waste gas, and belongs to the technical field of sintering flue gas treatment. BACKGROUND

[0002] Sintering is an important process in steel production, and is also one of the main sources of energy consumption and pollutant emission. By re-introducing part of the sintering flue gas into the sintering process, the waste heat of the flue gas can be effectively recovered, fuel consumption can be reduced, and pollutant emission can be decreased, which is an important way to achieve energy saving and emission reduction in the sintering process. The traditional approach is usually to introduce the exhaust gas discharged from the ring cooler into the ignition and heat preservation area of the sintering machine or above the sintering material layer without distinction or simple mixing. However, the exhaust gas discharged from the ring cooler at different stages of cooling the sintering ore has significant differences in key characteristics such as temperature and oxygen content. For example, the exhaust gas discharged from the high-temperature section of the ring cooler has high temperature but low oxygen content, while the exhaust gas discharged from the medium- and low-temperature sections has relatively high oxygen content but low temperature. Therefore, the traditional approach does not fully utilize the characteristics of the exhaust gas, resulting in low heat recovery efficiency or affecting the stability of the sintering process and the quality of the sintering ore due to inappropriate oxygen content. At the same time, the traditional approach lacks flexibility in regulating the injection area and injection amount of the exhaust gas, making it difficult to adapt to dynamic changes in sintering conditions and unable to achieve fine regulation of the atmosphere above the sintering material layer. The distribution of the introduced circulating flue gas in the circulating flue gas hood is often uneven, which may cause local overheating or underheating of the surface of the sintering material layer, affecting the uniformity and yield of the sintering ore.

[0003] Therefore, how to fully utilize the characteristics of the exhaust gas, improve energy utilization efficiency, improve the quality of the sintering ore and reduce pollutant emission is a technical problem to be solved in the current sintering flue gas circulation technology field. SUMMARY

[0004] Based on the above background, the purpose of the present application is to provide a sintering flue gas circulation system and method based on characteristic matching of ring cooling waste gas, which selectively utilizes the exhaust gas of different sections of the ring cooler in real time according to the requirements of temperature and oxygen content at different stages of the sintering process, and realizes efficient utilization of the ring cooling exhaust gas, optimization of the sintering process and improvement of the quality of the sintering ore by controlling the injection flow and regulating the flow field distribution in the circulating flue gas hood.

[0005] In order to achieve the above-mentioned purpose of the application, the present application provides the following technical solutions:

[0006] A sintering flue gas circulation system based on characteristic matching of ring cooling waste gas, comprising a sintering machine, an ignition and heat preservation hood and a circulating flue gas hood arranged above the sintering machine, and a ring cooler for cooling sintering ore, the sintering flue gas circulation system further comprising:

[0007] at least two independent ring cooling exhaust gas extraction circuits, each of which is connected to different segmented areas of the ring cooler capable of extracting ring cooling exhaust gas with different temperature and oxygen content combination characteristics, and each of which is provided with an online sensor assembly for real-time monitoring of the temperature and oxygen content of the ring cooling exhaust gas extracted by the ring cooling exhaust gas extraction circuit;

[0008] a plurality of ring cooling exhaust gas injection circuits corresponding to the number of ring cooling exhaust gas extraction circuits, each of which directly delivers the ring cooling exhaust gas extracted by the ring cooling exhaust gas extraction circuit as process gas to different injection zones above the sintering machine, the injection zones at least including a first injection zone arranged inside the ignition holding cover and a second injection zone arranged in the head region of the circulating flue gas cover, and each of which is provided with a flow control assembly;

[0009] a flow field control device, which includes at least one guide vane assembly with an opening degree controlled by a driving module, and is arranged inside the circulating flue gas cover; and,

[0010] a control unit electrically connected to the online sensor assembly, the flow control assembly and the driving module of the flow field control device, and configured to execute the following control strategies:

[0011] based on the temperature and oxygen content of the ring cooling exhaust gas monitored by the online sensor assembly in real time, and in combination with the predetermined target temperature and predetermined target oxygen concentration of the ignition stage and the pre-sintering stage of the sintering machine, the operation of one or more selected ring cooling exhaust gas extraction circuits and ring cooling exhaust gas injection circuits is started and adjusted;

[0012] the flow control assembly is controlled to allow the selected ring cooling exhaust gas to be injected into the first injection zone and the second injection zone at a calculated flow rate, respectively;

[0013] based on the temperature and oxygen content combination characteristics of the injected ring cooling exhaust gas and the flow rate of the ring cooling exhaust gas, the opening degree of the guide vane assembly of the flow field control device is controlled.

[0014] As a preferred embodiment, the injection zone further includes a third injection zone arranged in the middle or rear region of the circulating flue gas cover.

[0015] As a preferred embodiment, the number of guide vane assemblies is multiple, and the multiple guide vane assemblies are distributed along the length direction of the circulating flue gas cover to form a guide vane array.

[0016] Preferably, the deflector assembly is arranged in parallel along the length direction of the circulating flue gas cover, each of the deflector assembly comprises a plurality of deflector pieces arranged in intervals along the extending direction of the column and rotatable around the side shaft, the deflector pieces are hinged to the circulating flue gas cover, the other side end of each of the deflector pieces is fixed with a driving gear, the circulating flue gas cover is provided with a long rack arranged along the extending direction of the deflector assembly, the long rack is engaged with the driving gears of all the deflector pieces of the deflector assembly, at least one end of the long rack is fixedly connected with the output end of a driving module arranged outside the circulating flue gas cover, the driving module drives the long rack to produce linear reciprocating motion so as to drive all the deflectors in the deflector assembly to rotate synchronously to adjust the deflection angle, and the control unit can control the driving modules driving different deflector assemblies respectively, so that the deflectors in any two adjacent deflector assemblies have opposite deflection directions.

[0017] A sintering flue gas circulating method based on ring cooler waste gas characteristic matching, applied to a sintering flue gas circulating system comprising a sintering machine, an ignition holding cover arranged above the sintering machine, a circulating flue gas cover, and a ring cooler for cooling sintered ore, the method comprising the following steps:

[0018] Through at least two independent ring cooler waste gas extraction circuits, ring cooler waste gas is extracted from different segmented areas of the ring cooler, and the temperature and oxygen content of the extracted ring cooler waste gas are monitored in real time by an online sensor assembly arranged on each ring cooler waste gas extraction circuit;

[0019] The extracted ring cooler waste gas is used as process gas and injected into different injection areas above the sintering machine through corresponding ring cooler waste gas injection circuits, the injection areas at least include a first injection area inside the ignition holding cover and a second injection area in the head region of the circulating flue gas cover;

[0020] Through a control unit, based on the temperature and oxygen content of the ring cooler waste gas monitored in real time by the online sensor assembly, and in combination with the predetermined target temperature and predetermined target oxygen concentration of the sintering machine ignition stage and the pre-sintering stage, the operation of the selected one or more ring cooler waste gas extraction circuits and ring cooler waste gas injection circuits is selected and adjusted;

[0021] Through a control unit, the flow control assembly arranged on each ring cooler waste gas injection circuit is controlled, so that the selected ring cooler waste gas is injected into the first injection area and the second injection area at a calculated flow rate respectively;

[0022] By the control unit, according to the temperature and oxygen content combination characteristics of the injected annular cooling waste gas and the flow of the annular cooling waste gas, the guide vane assembly opening degree of the flow field regulation device arranged in the circulating flue gas hood is controlled.

[0023] As preferred, the injection area further comprises at least one third injection area of the middle or rear area of the circulating flue gas hood, and the annular cooling waste gas is selectively injected by the corresponding annular cooling waste gas injection circuit and flow regulation assembly according to the predetermined process requirement of the middle and rear stages of the sintering through the control unit.

[0024] As preferred, the control unit follows the following preset priority rules when selecting the optimal matching annular cooling waste gas, first, the heat requirement of the first injection area in the ignition holding hood is met, and second, the oxygen content and preheating requirement of the second injection area in the head area of the circulating flue gas hood are met.

[0025] As preferred, the method further comprises the following steps: reading the periodically input preset sinter quality indicators and / or energy consumption indicators by the control unit, and adjusting the predetermined target temperature and predetermined target oxygen concentration of the ignition stage and the front stage of the sintering machine.

[0026] Compared with the prior art, the present application has the following advantages:

[0027] The sinter flue gas circulating system and method based on the characteristic matching of annular cooling waste gas of the present application can match the annular cooling waste gas with different characteristics to the specific requirements of different stages of the sintering process through shunt extraction, real-time monitoring and selection, maximize the recycling of waste heat and useful components of the waste gas, provide a more stable and uniform process atmosphere for the sintering material layer through the control of the injection flow and the flow field distribution in the circulating flue gas hood, reduce the sintering process instability phenomenon caused by the fluctuation or uneven distribution of the waste gas characteristics, directly reduce the fuel consumption in the ignition and sintering process through the efficient recycling of the waste heat of the annular cooling waste gas, at the same time, the internal circulation of the flue gas also greatly reduces the amount of flue gas and the total amount of pollutants in the flue gas. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of the provided drawings.

[0029] Figure 1 is a structural schematic diagram of a sinter flue gas circulating system based on the characteristic matching of annular cooling waste gas of the present application;

[0030] Figure 2 is a structural schematic diagram of a flow field regulation device in the present application;

[0031] Figure 3 is Figure 2 is a partial enlarged view of A part in figure 1;

[0032] Figure 4 is a technical effect comparison chart of the present application and the traditional sintering flue gas circulation scheme;

[0033] In the figure: 1, sintering machine; 2, ignition heat preservation cover; 3, circulating flue gas cover; 4, circular cooler; 5, circular cooler waste gas leading-out loop; 6, online sensor assembly; 7, circular cooler waste gas injection loop; 8, flow control assembly; 9, first injection zone; 10, second injection zone; 11, third injection zone; 12, flow field control device; 13, deflector assembly; 14, driving module; 15, control unit; 16, multi-tube dust collector; 17, waste heat recovery boiler; 18, circulating flue gas induced draft fan; 31, circulating flue gas cover head region; 32, circulating flue gas cover middle region; 33, circulating flue gas cover rear region; 41, circular cooler high-temperature section; 42, circular cooler medium-temperature section; 43, circular cooler low-temperature oxygen-rich section; 5a, first circular cooler waste gas leading-out loop; 5b, second circular cooler waste gas leading-out loop; 5c, third circular cooler waste gas leading-out loop; 6a, temperature sensor; 6b, oxygen content analyzer; 7a, first circular cooler waste gas injection loop; 7b, second circular cooler waste gas injection loop; 7c, third circular cooler waste gas injection loop; 8a, first induced draft fan; 8b, second induced draft fan; 8c, third induced draft fan; 131, deflector piece; 132, driving gear; 133, long rack. DETAILED DESCRIPTION

[0034] The technical solutions of the present application will be further described in detail below with specific examples and in conjunction with the drawings. It should be understood that the implementation of the present application is not limited to the following examples, and any form of variation and / or change made to the present application will fall within the scope of protection of the present application.

[0035] In the present application, unless specified, all parts, percentages are weight units, and the equipment and raw materials used can be purchased from the market or commonly used in the art. The methods in the following examples, unless otherwise specified, are conventional methods in the art. The components or equipment in the following examples, unless otherwise specified, are general standard components or components known to those skilled in the art, and their structure and principles are known to those skilled in the art through technical manuals or through conventional experimental methods.

[0036] The embodiments of the present application will be described in detail below in conjunction with the drawings. In the following detailed description, many specific details are set forth in order to provide a thorough understanding of the embodiments of the present application. However, one or more embodiments can be practiced without these specific details.

[0037] Embodiments of the present invention disclose a sintering flue gas recirculation system based on the matching of annular cooling exhaust gas characteristics, such as... Figure 1 As shown, this system is applied in a typical belt sintering process, including a sintering machine 1, an ignition and heat preservation hood 2 for ignition and heat preservation, and a circulating flue gas hood 3 for introducing circulating flue gas, all arranged sequentially along the length of the sintering machine 1. An annular cooler 4 for cooling the high-temperature sintered ore is connected to the end of the sintering machine 1. The sintering flue gas circulation system also includes three independent annular cooler exhaust gas outlet circuits 5, three annular cooler exhaust gas injection circuits 7, a flow field control device 12, and a control unit 15.

[0038] Three independent annular cooling exhaust gas outlet circuits 5 are designated as the first annular cooling exhaust gas outlet circuit 5a, the second annular cooling exhaust gas outlet circuit 5b, and the third annular cooling exhaust gas outlet circuit 5c. These outlet circuits are connected to different segmented regions on the annular cooler 4, each capable of outleting different combinations of temperature and oxygen content. The first annular cooling exhaust gas outlet circuit 5a is connected to the high-temperature section 41 of the annular cooler 4. The exhaust gas in this section typically has a high temperature, reaching 600-800°C, but a low oxygen content, usually 5%-10%. The second annular cooling exhaust gas outlet circuit 5b is connected to the medium-temperature section 42 of the annular cooler 4. The exhaust gas in this section has a moderate temperature, reaching 300-500°C, and a moderate oxygen content, usually 10%-15%. The third annular cooling exhaust gas outlet circuit 5c is connected to the low-temperature, oxygen-enriched section 43 of the annular cooler 4. The temperature of this section of exhaust gas is relatively low, usually 150-300°C, but the oxygen content is high, reaching 15%-20%, which is close to or slightly lower than the oxygen content in the air.

[0039] Each of the annular cooling exhaust gas outlet circuits 5a, 5b, and 5c is equipped with an online sensor assembly 6 for real-time monitoring of key parameters of the outlet annular cooling exhaust gas. The online sensor assembly 6 includes a temperature sensor 6a for monitoring temperature and an oxygen content analyzer 6b for monitoring oxygen content. Specifically, the temperature sensor 6a is a sheathed thermocouple, and the oxygen content analyzer 6b is a zirconia oxygen analyzer.

[0040] Three annular cold exhaust gas injection circuits 7 correspond to three annular cold exhaust gas outlet circuits, namely the first annular cold exhaust gas injection circuit 7a, the second annular cold exhaust gas injection circuit 7b, and the third annular cold exhaust gas injection circuit 7c. High temperatures are required inside the ignition insulation hood 2 to maintain the ignition temperature of the sintering material layer and reduce ignition fuel consumption. Therefore, the first annular cold exhaust gas injection circuit 7a mainly transports the high-temperature, low-oxygen exhaust gas drawn from the first annular cold exhaust gas outlet circuit 5a to the first injection zone 9 located inside the ignition insulation hood 2. The head region 31 of the circulating flue gas hood is located after the ignition insulation hood. Injecting exhaust gas with appropriate temperature and oxygen helps preheat the subsequently entering sintering material layer and provides the necessary oxygen for the front stage of sintering, stabilizing the combustion zone. Therefore, the second annular cold exhaust gas injection circuit 7b transports the medium-temperature, medium-oxygen exhaust gas drawn from the second annular cold exhaust gas outlet circuit 5b to the second injection zone 10 located in the head region 31 of the circulating flue gas hood 3. In the later stages of the sintering process, oxygen needs to be supplemented to ensure complete sintering or to adjust the temperature distribution. Therefore, the third ring cold exhaust gas injection circuit 7c will transport the low-temperature oxygen-rich exhaust gas drawn from the third ring cold exhaust gas extraction circuit 5c to the third injection zone 11 located in the middle region 32 or the rear region 33 of the circulating flue gas hood 3.

[0041] Each of the ring-cooled exhaust gas injection loops 7a, 7b, and 7c is equipped with a flow control component 8, specifically an induced draft fan controlled by a frequency converter, namely the first induced draft fan 8a, the second induced draft fan 8b, and the third induced draft fan 8c.

[0042] like Figure 2 and Figure 3 As shown, the flow field control device 12 includes multiple guide vane assemblies 13 distributed along the length of the circulating flue gas hood 3, forming a guide vane array. Each guide vane assembly 13 is arranged parallel to the length of the circulating flue gas hood 3 (i.e., the rotation axis direction of the guide vane is perpendicular to the sintering machine's operating direction). Each guide vane assembly 13 includes multiple guide vane members 131 that are spaced apart along the column (i.e., perpendicular to the sintering machine's operating direction) and can independently rotate about their side rotation axis. These guide vane members 131 are hinged to the internal support structure of the circulating flue gas hood 3 via rotation axes. A drive gear 132 is fixedly connected to the end of each guide vane member 131 on the other side (non-rotation axis side).

[0043] For each baffle assembly 13, the circulating flue gas hood 3 has a long rack 133 extending along the direction of the baffle assembly. The long rack 133 meshes with the drive gears 132 of all the baffle components 131 within the baffle assembly. One end of the long rack 133 is fixedly connected to the output end of the drive module 14 located outside the circulating flue gas hood 3 via a connecting rod. The drive module 14 uses an electric push rod or a cylinder to drive the long rack 133 to produce linear reciprocating motion. When the long rack 133 moves, through the gear and rack meshing, it can synchronously drive all the baffle components 131 within the baffle assembly 13 to rotate around their respective axes, thereby uniformly adjusting their deflection angle (i.e., opening).

[0044] The control unit 15 can control the drive modules 14 that drive different guide vane assemblies 13 respectively, so that the guide vane members 131 in any two adjacent guide vane assemblies have relative deflection directions. Specifically, if the guide vane member of one guide vane assembly deflects upward, the guide vane member of the adjacent guide vane assembly deflects downward, thereby creating a guiding effect of airflow divergence and airflow disturbance within the circulating flue gas hood, forming divergent flow and crossflow.

[0045] The control unit 15 employs a programmable logic controller (PLC) and is electrically connected to all online sensor components 6, all flow control components 8, and all drive modules 14. The control unit 15 is configured to execute the following core control strategies:

[0046] The control unit 15 collects real-time data from the online sensor components 6, monitoring the temperature and oxygen content of each stream of annular cooling exhaust gas (from the high-temperature section 41, the medium-temperature section 42, and the low-temperature oxygen-enriched section 43). Simultaneously, the control unit 15 stores pre-set target temperatures and oxygen concentrations for the ignition stage of the sintering machine and for the pre-sintering, mid-sintering, and post-sintering stages. These target values ​​can be preset based on process parameters such as the type of sintered ore, bed thickness, and sintering speed, and can also be updated based on subsequent optimization adjustments. The control unit 15 uses a built-in matching algorithm to compare the characteristics of each actual exhaust gas stream with the target requirements of the current sintering stage, selecting one or more streams of annular cooling exhaust gas whose temperature and oxygen content combination best matches the target. During selection, a preset priority rule is followed: first, ensuring that the heat demand of the first injection zone 9 within the ignition insulation hood 2 is met, i.e., prioritizing exhaust gas with a sufficiently high temperature, i.e., exhaust gas from the high-temperature section 41; second, considering the oxygen content and preheating temperature requirements of the second injection zone 10 in the head region 31 of the circulating flue gas hood 3, selecting exhaust gas from the medium-temperature section 42. In other words, based on the predetermined target temperature of the ignition insulation hood, the flow control device of the high-temperature section exhaust gas injection circuit is controlled to ensure sufficient high-temperature exhaust gas injection at the required temperature. This is a critical process guarantee and has the highest priority. Based on the predetermined target temperature and target oxygen concentration at the head of the circulating flue gas hood, the flow control device of the medium-temperature section exhaust gas injection circuit is controlled to adjust the injection flow rate. This has the second priority. Under the premise of ensuring the highest priority target, if the characteristics of the medium-temperature section exhaust gas cannot fully meet the predetermined target, the control unit will make every effort to utilize the existing medium-temperature section exhaust gas.

[0047] After selecting a suitable annular cooling exhaust gas source, the control unit 15 calculates the flow rate of each exhaust gas to be injected into the first injection zone 9, the second injection zone 10, and the possible third injection zone 11 based on the target temperature, target oxygen concentration, target heat load, and the actual characteristics of the selected exhaust gas.

[0048] Then, the control unit 15 outputs a control signal to the corresponding flow control component 8 to adjust the fan speed so that the selected annular cooling exhaust gas is injected into the designated injection area at the calculated flow rate.

[0049] Based on the comprehensive characteristics of the circulating cold exhaust gas currently injected into the circulating flue gas hood 3 and the temperature distribution requirements on the surface of the sintering material layer, the control unit 15 outputs control signals to each drive module 14 of the flow field control device 12.

[0050] By controlling the displacement of the long rack 133, the deflection angle of the guide plates 131 within each guide plate assembly 13 is adjusted. If high-temperature exhaust gas is injected, the guide plates are needed to distribute it more evenly above the material layer to avoid local overheating. If low-temperature oxygen-rich exhaust gas is injected, the guide plates are needed to guide it to specific areas requiring oxygen supplementation. By controlling the relative deflection of adjacent guide plate assemblies, a finer flow field can be formed. The characteristics and quantity of the injected gas determine the initial state of the airflow, and the flow field control device optimizes the distribution of the airflow within the hood and its contact with the material layer based on this initial state. If the gas flow rate and temperature at the head of the hood are large, the opening of the guide plates will be adjusted to promote its rapid and uniform spread and downward pressure on the material layer. If the gas injected at the tail of the hood is mainly for oxygen supplementation, the opening of the guide plates will be adjusted to ensure thorough mixing with its own circulating flue gas.

[0051] The control unit 15 can also be configured to periodically receive preset sinter quality indicators and / or energy consumption indicators input by the operator or transmitted from other production management systems. Accordingly, the control unit 15 adjusts the preset target temperature and target oxygen concentration for the sintering machine ignition stage and the pre-sintering stage.

[0052] In addition to the multi-point injection of the aforementioned annular cooling exhaust gas, this system also includes a path for recycling the exhaust gas generated by the sintering machine itself. Specifically, the sintering exhaust gas drawn from the sintering machine's exhaust gas outlet first enters the multi-tube dust collector 16 for physical dust removal, removing most of the solid particles. Subsequently, the preliminarily purified sintering exhaust gas enters the waste heat recovery boiler 17, where its sensible heat is used to generate steam or heat other media, achieving cascaded energy utilization. After cooling and waste heat recovery, the sintering exhaust gas is then pressurized by the circulating flue gas induced draft fan 18 to form circulating flue gas, which is then transported to the tail area of ​​the circulating flue gas hood, i.e., the third injection zone.

[0053] In the tail section of the circulating flue gas hood, the flue gas, which has undergone dust removal and waste heat recovery and recirculated back from the sintering machine itself, mixes with the annular cooling exhaust gas drawn from the low-temperature oxygen-enriched section of the annular cooler and injected into this area. The circulating flue gas, as the main gas return flow, helps to establish and maintain a certain positive pressure in the tail section of the circulating flue gas hood, preventing the intake of external cold air and forming the basis for a macroscopic airflow towards the head of the sintering machine. The low-temperature oxygen-enriched section annular cooling exhaust gas injected here serves as a supplement, further adjusting the total gas volume and pressure in this area. The flue gas circulating within the sintering machine itself has a significantly reduced temperature after waste heat recovery, and its oxygen content is usually low, while the content of reducing gases such as CO may be high. The exhaust gas drawn from the low-temperature oxygen-enriched section of the annular cooler may have a slightly higher or similar temperature to the circulating flue gas, but its key characteristic is its higher oxygen content. The mixture of the two gases effectively increases the overall oxygen concentration in the tail section of the sintering system, providing supplemental oxygen for any unburned fuel that may remain in the later stages of the sintering process. This promotes complete combustion, reduces CO emissions, and may also provide some insulation or slow cooling to the sintering bed in that area. Even the recirculated flue gas after waste heat recovery may still carry some unutilized waste heat and latent chemical heat. The supplementation of the low-temperature oxygen-enriched section's annular cooling exhaust gas, especially the oxygen it carries, helps to further release and utilize this latent heat in the later stages of sintering. Simultaneously, the sensible heat of the annular cooling exhaust gas itself is also recovered.

[0054] An embodiment of the present invention also discloses a sintering flue gas recirculation method based on the matching of the characteristics of the annular cooling exhaust gas, the steps of which are as follows.

[0055] Step 1: The first, second, and third ring-cooled exhaust gas lead-out circuits 5a, 5b, and 5c respectively lead out the ring-cooled exhaust gas from the high-temperature section 41, the medium-temperature section 42, and the low-temperature oxygen-enriched section 43 of the ring cooler 4, and the temperature and oxygen content of each exhaust gas are monitored in real time by the online sensor assembly 6, and the data is transmitted to the control unit 15.

[0056] Step 2: The control unit 15 selects one or more annular cooling exhaust gases with optimal characteristics based on the predetermined target temperature and oxygen concentration of the current sintering stage, combined with the real-time exhaust gas characteristics monitored in Step 1, and following the preset priority rules.

[0057] Step 3: The control unit 15 calculates the flow rate of the selected waste gas to be injected into the first injection zone 9, the second injection zone 10 and / or the third injection zone 11, and controls the corresponding flow control components 8a, 8b and 8c to inject the selected waste gas according to the calculated flow rate.

[0058] Step 4: The control unit 15 controls the drive module 14 of each guide plate assembly 13 in the flow field regulation device 12 according to the characteristics and flow rate of the injected exhaust gas and the target flow field distribution requirements in the circulating flue gas hood 3, adjusts the opening of the guide plate 131, and optimizes the distribution of exhaust gas above the sintering material layer.

[0059] Step 5: The control unit 15 periodically receives the sinter quality and energy consumption indicators, and adjusts the predetermined target temperature and oxygen concentration accordingly.

[0060] By adopting the sintering flue gas recirculation system and method based on the characteristic matching of annular cooling exhaust gas provided by this invention, and comparing it with existing traditional sintering flue gas recirculation technologies, the performance comparison results are as follows: Figure 4 As shown.

[0061] It can be seen that the present invention has a significant reduction in solid fuel consumption, indicating that the present invention effectively reduces the dependence of the sintering process on external fuel by accurately matching and efficiently utilizing the heat energy contained in the annular cooling exhaust gas.

[0062] The present invention significantly improves the strength of the sinter drum and the yield of sintered ore, indicating that the present invention improves the temperature uniformity of the sintering material layer by controlling the characteristics of the injected gas and the flow field inside the shroud, which directly promotes the stability of the sintering process and the improvement of the quality of sintered ore.

[0063] The present invention significantly reduces SO2 and NOx emission concentrations in flue gas, indicating that by optimizing the combustion atmosphere and improving energy utilization efficiency, the present invention promotes the internal transformation and absorption of some pollutants.

[0064] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A sintering flue gas circulation system based on matching the characteristics of annular cooling exhaust gas, comprising a sintering machine (1), an ignition insulation hood (2) and a circulating flue gas hood (3) disposed above the sintering machine (1), and an annular cooler (4) for cooling sintered ore, characterized in that: The sintering flue gas recirculation system also includes: At least two independent annular cooling exhaust gas outlet circuits (5) are provided. Each annular cooling exhaust gas outlet circuit (5) is connected to different segmented areas of the annular cooler (4) that can draw out annular cooling exhaust gas with different temperature and oxygen content combinations. Each annular cooling exhaust gas outlet circuit (5) is provided with an online sensor assembly (6). The online sensor assembly (6) is used to monitor the temperature and oxygen content of the annular cooling exhaust gas drawn out by the annular cooling exhaust gas outlet circuit (5) in real time. A cooling gas injection circuit (7) corresponding to the number of cooling gas outlet circuits (5) is provided. Each cooling gas injection circuit (7) directly delivers the cooling gas drawn out by the cooling gas outlet circuit (5) as process gas to different injection zones above the sintering machine (1). The injection zones include at least a first injection zone (9) set inside the ignition insulation cover (2) and a second injection zone (10) set in the head area (31) of the circulating flue gas cover. Each cooling gas injection circuit (7) is provided with a flow control component (8). A flow field control device (12) includes at least one guide vane assembly (13) whose opening is controlled by a drive module (14), the guide vane assembly (13) being disposed inside the circulating flue gas hood (3); and, Control unit (15), which is electrically connected to the online sensor assembly (6), the flow control assembly (8) and the drive module (14) of the flow field control device (12); The number of the baffle assembly (13) is multiple, and the multiple baffle assemblies (13) are distributed along the length direction of the circulating flue gas hood (3) to form a baffle array; The guide vane assembly (13) is arranged parallel to the length direction of the circulating flue gas hood (3). Each guide vane assembly (13) includes multiple guide vane members (131) arranged at intervals along the column extension direction, which can independently rotate about their side pivots. The guide vane members (131) are hinged to the circulating flue gas hood (3). A drive gear (132) is fixed to the other end of each guide vane member (131). Inside the circulating flue gas hood (3), corresponding to each guide vane assembly (13), there is a long rack (133) arranged along the extension direction of the guide vane assembly (13). The long rack (133) is connected to the guide vane assembly (13). The drive gears (132) of all the guide vane components (131) of 13) mesh with each other, and at least one end of the long rack (133) is fixedly connected to the output end of the drive module (14) located outside the circulating flue gas hood (3). The drive module (14) causes the long rack (133) to generate linear reciprocating motion, thereby driving all the guide vanes in the guide vane assembly (13) to rotate synchronously to adjust their deflection angle. Furthermore, the control unit (15) can control the drive modules (14) that drive different guide vane assemblies (13) respectively, so that the guide vanes in any two adjacent guide vane assemblies (13) have relative deflection directions.

2. The sintering flue gas recirculation system based on the matching characteristics of annular cooling exhaust gas according to claim 1, characterized in that: The injection zone also includes a third injection zone (11) located in the middle or rear part of the circulating flue gas hood (3).

3. A sintering flue gas recirculation method based on matching the characteristics of annular cooling exhaust gas, applied to the sintering flue gas recirculation system as described in claim 1, characterized in that: The method includes the following steps: Through at least two independent annular cooling exhaust gas extraction circuits (5), annular cooling exhaust gas with different temperature and oxygen content combination characteristics can be extracted from different segmented areas of the annular cooler (4), and the temperature and oxygen content of the extracted annular cooling exhaust gas are monitored in real time by an online sensor assembly (6) set on each annular cooling exhaust gas extraction circuit (5). The various ring-cooled exhaust gases are used as process gases and are directly injected into different injection zones above the sintering machine (1) through their respective ring-cooled exhaust gas injection circuits (7). The injection zones include at least the first injection zone (9) inside the ignition insulation hood (2) and the second injection zone (10) in the head area (31) of the circulating flue gas hood. The control unit (15) selects to open and adjust the operation of one or more loop cooling exhaust gas outlet circuits (5) and loop cooling exhaust gas injection circuits (7) based on the temperature and oxygen content of the ring cooling exhaust gas monitored in real time by the online sensor assembly (6) and the predetermined target temperature and predetermined target oxygen concentration of the ignition stage and the pre-sintering stage of the sintering machine (1). The control unit (15) controls the flow control component (8) set on each annular cooling exhaust gas injection circuit (7) so that the selected annular cooling exhaust gas is injected into the first injection zone (9) and the second injection zone (10) respectively at the calculated flow rate. The control unit (15) controls the opening of the guide plate assembly (13) of the flow field control device (12) located inside the circulating flue gas hood (3) according to the combined characteristics of the temperature and oxygen content of the injected circulating flue gas and the flow rate of the circulating flue gas.

4. The sintering flue gas recirculation method based on matching the characteristics of annular cooling exhaust gas according to claim 3, characterized in that: The injection zone also includes at least one third injection zone (11) in the middle or rear region of the circulating flue gas hood (3), through which the control unit (15) selectively injects the circulating flue gas by the corresponding circulating flue gas injection circuit (7) and flow control component (8) according to the predetermined process requirements of the middle and rear section of sintering.

5. The sintering flue gas recirculation method based on matching the characteristics of annular cooling exhaust gas according to claim 3, characterized in that: When selecting the optimal matching ring-cooled exhaust gas, the control unit (15) follows the following preset priority rules: firstly, it meets the heat demand of the first injection zone (9) in the ignition insulation cover (2), and secondly, it meets the oxygen content and preheating demand of the second injection zone (10) in the head area (31) of the circulating flue gas cover.

6. The sintering flue gas recirculation method based on matching the characteristics of annular cooling exhaust gas according to claim 3, characterized in that: The method further includes the following steps: by reading the periodically input preset sinter quality indicators and / or energy consumption indicators through the control unit (15), the predetermined target temperature and predetermined target oxygen concentration of the ignition stage and the pre-sintering stage of the sintering machine (1) are adjusted.

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