A dual-fan sintering machine group single-fan operation thick material layer sintering device and method

Abstract

The application discloses a kind of double-fan sintering machine group single-fan operation thick material layer sintering device and method, belong to metallurgical sintering technical field.The technical scheme of the present application mainly includes: first isolation stops fan and adjusts valve baffle to complete flue gas flow balance, optimizes raw material ratio and moisture to reduce material layer resistance, adopts double-layer loose material to improve ventilation condition, time-sharing period dynamic adjustment fan air pressure adapts sintering process, combined with whole system air leakage control and sintering endpoint linkage regulation and control, without modifying main equipment can realize 800-920mm thick material layer stable sintering.The present application solves the problem of insufficient air volume, uneven airflow distribution, uneven thick material layer sintering, large operating condition fluctuation and high energy consumption when the double-fan sintering machine group operates with single fan, can improve the quality of sintered ore, reduce production energy consumption, and ensure continuous operation of production line during equipment maintenance and fault period.

Description

Technical Field

[0001] This invention relates to the field of metallurgical sintering technology, specifically to a sintering device and method for thick material layers with single-fan operation in a dual-fan sintering unit. Background Technology

[0002] Currently, large and medium-sized steel enterprises generally use a parallel arrangement of two main exhaust fans in their large-scale sintering equipment, designed for simultaneous operation of both units to meet the production needs of large capacity and thick material layers. However, in actual production and operation, factors such as sudden fan failures, production load adjustments, and environmental regulations often cause the unit to switch to single-fan operation mode, reducing the system's air supply capacity to about half that of the dual-fan mode. Since thick material layer sintering inherently has significant ventilation resistance, this creates a prominent contradiction between single-fan operation and thick material layer production, becoming a long-standing technical challenge that the industry has failed to resolve effectively.

[0003] Several technical challenges were exposed under this operating condition. First, the limited airflow made it difficult to penetrate the material layer, and the thick material layer itself had greater ventilation resistance, resulting in incomplete combustion reaction in the lower part of the material and easy production of undercooked material. Second, the flues on both sides of the sintering machine are mostly symmetrical or asymmetrical structures. When a single fan is running, the flow resistance on both sides is significantly different, the airflow from the air box is uneven, the ventilation conditions in the transverse and longitudinal directions of the material layer are greatly different, the sintering temperature field is disordered, the sintering endpoint frequently deviates, and the production stability is greatly reduced. Third, in order to make up for the airflow gap, the operating fan is forced to operate at high frequency for a long time, which significantly increases power consumption. Coupled with problems such as material layer caking and moisture fluctuation, the amount of returned ore increases, and the overall production cost increases. Fourth, most of the existing publicly available technologies are for normal parallel operation of dual fans, or are only suitable for simple single fan operation mode for thin material layers. At present, the industry lacks a complete set of systematic process solutions specifically for dual fan units, single fan operation, and continuous production of thick material layers. In order to ensure production, enterprises can only be forced to reduce the material layer and reduce capacity, resulting in significant economic losses.

[0004] Chinese patent CN116294619A discloses a single-fan sintering production control method under emergency conditions. The method reduces the feeding amount to a low load level of less than 0.7 times the effective exhaust area of ​​the sintering machine, increases the quicklime ratio to more than 5%, and controls the material layer thickness to 650 mm or less. This is to ensure the granulation effect of the mixture 18 and the air permeability of the material layer. However, the material layer thickness does not exceed 650 mm, which falls into the category of thin material layer low load emergency. It cannot achieve stable production with a material layer thickness of more than 800 mm, nor does it address the issue of flue airflow balance after switching between dual-fan units.

[0005] CN117628906A discloses a single-fan thick-layer sintering production method, with the material layer thickness set at 850-870mm. By increasing the ratio of quicklime to returned ore, controlling the moisture content of the mixture to 6.3%-6.5%, and increasing the thickness of the bottom layer material to 90-100mm, the sinter output under single-fan operation can reach 80%-85% of that under dual-fan operation. Although this method enters the thick-layer range, the material layer range is relatively narrow. The technical means focus on batching, moisture content, and bottom layer material adjustment, without addressing the flue gas balancing of the dual-fan structure, dynamic wind pressure matching at different time periods, and multi-parameter linkage control at the sintering endpoint. Furthermore, it does not provide a solution to the unique airflow imbalance problem of dual-fan parallel units when a single fan is in operation.

[0006] Announcement No. CN111826517B discloses a sintering material and method for ultra-thick material layers. By setting vertical dividing strips composed of a first sintered ore in the material layer, the mixture to be sintered is divided into zones, thereby reducing ventilation resistance, increasing the sintering speed to 26.1 mm / min, and achieving a yield of 85%. This method focuses on optimizing the material formulation and innovating the layered material distribution structure under ultra-thick material layer conditions. However, it does not address single-fan or dual-fan parallel operation conditions, nor does it include content related to negative pressure dynamic control and flue gas balancing. Summary of the Invention

[0007] The purpose of this invention is to provide a sintering device and method for a thick material layer in a dual-fan sintering unit with single-fan operation. It achieves production upgrades by optimizing operating parameters, with low modification costs and short implementation cycles. It can stably achieve sintering of 800-920mm thick material layers, ensure continuous operation of the production line during equipment maintenance and troubleshooting, and simultaneously achieve the comprehensive goals of improving quality, reducing consumption, and stabilizing production, thus solving the problems mentioned in the background art.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A single-fan operation thick-layer sintering device for a dual-fan sintering unit is characterized by comprising two main exhaust fans arranged in parallel, two flues, multiple sets of air boxes, a double-layer loose material distribution mechanism, a raw material mixing and batching mechanism, a single-fan air pressure control module, an air leakage sealing component, and a sintering endpoint control module; the two main exhaust fans are respectively the running fan and the stopped fan, and the air inlet of each main exhaust fan is connected to the end of a flue; each main exhaust fan is equipped with a flue isolation valve at its inlet and outlet positions, and an adjustable connecting equalization valve is provided between the two flues; multiple sets of air boxes are arranged sequentially below the sintering trolley along the trolley's travel direction, each set of air boxes... A butterfly valve is installed at the outlet of the box. Each group of air boxes is connected to the flue on the corresponding side through an air duct. Each air duct connected to each group of air boxes is equipped with an independently adjustable baffle. The double-layer loose material feeding mechanism is located directly above the sintering trolley. The discharge end of the raw material mixing and batching mechanism corresponds to the feed end of the double-layer loose material feeding mechanism. The single fan pressure control module is electrically connected to the control terminal of the main exhaust fan. The air leakage sealing component is arranged at the joint leakage points of the sintering system. The detection element of the sintering endpoint control module is installed inside the flue. The control output terminal is connected to the control terminal of the sintering machine drive mechanism and the main exhaust fan, respectively.

[0010] Preferably, the double-layer loose material feeding mechanism is provided with a bottom material feeding unit, a multi-roller feeder, a liftable loose tooth and a leveling mechanism in sequence along the traveling direction of the sintering trolley. The rear end of the leveling mechanism is fixedly connected to a leveling slide, and the working surface of the leveling slide is parallel to the surface of the trolley grate.

[0011] Preferably, the adjustable loose teeth are divided into three groups: upper, middle, and lower. Each group of loose teeth is arranged at intervals along the vertical direction and is connected to a vertical lifting adjustment structure.

[0012] Preferably, the raw material mixing and batching mechanism is composed of a batching unit, a primary mixer, and a secondary mixer connected in series; the discharge end of the batching unit is connected to the feed end of the primary mixer, and the discharge end of the primary mixer is connected to the feed end of the secondary mixer; the internal cavity of the primary mixer is equipped with a preliminary humidification spray assembly, and the internal cavity of the secondary mixer is equipped with an atomizing spray water replenishment assembly. The two-stage mixer is used to complete the mixing and granulation of the mixture.

[0013] Preferably, the sintering endpoint control module includes a negative pressure sensor, an exhaust gas temperature sensor, a flue gas oxygen content sensor, and an integrated control module; the negative pressure sensor, exhaust gas temperature sensor, and flue gas oxygen content sensor are all fixedly installed on the inner wall of the flue, and the signal output terminals of each sensor are connected to the signal input terminal of the integrated control module. The control output terminal of the integrated control module is respectively connected to the control terminal of the sintering machine drive mechanism and the main exhaust fan; the air leakage sealing components are respectively set at the gap of the trolley side plate, the splicing point of the trolley grate plate, the flexible connection section of the air box, and the flue flange interface.

[0014] A method for sintering thick material layers using a single fan in a dual-fan sintering unit includes the following steps:

[0015] Step 1: Select one main exhaust fan as the operating fan and put it into operation. Close the flue isolation valve at the inlet and outlet of the stop fan to complete the physical isolation. Open and adjust the opening of the adjustable connecting equalization valve, and adjust the opening of the regulating baffle in each air duct one by one to keep the negative pressure ratio of the flue on both sides in the range of 1.04-1.22.

[0016] Step 2: After weighing the raw materials according to the set mass ratio through the batching unit, the raw materials are sent to the primary mixer. After preliminary mixing and humidification, the raw materials are sent to the secondary mixer for atomization and water replenishment to complete the granulation of the mixture.

[0017] Step 3: The bottom material is laid on the surface of the trolley grate by the bottom material laying unit to form a bottom material layer. Then, the mixed material is laid on the bottom material layer by the multi-roller material spreader to form a mixed material layer. During the material spreading process, the material is loosened by the liftable loosening teeth. Finally, the total material layer thickness is flattened to 800-920mm by the flat material slide of the flat material mechanism.

[0018] Step 4: Divide the entire sintering process into multiple operating zones using the single-fan air pressure control module, and adjust the system negative pressure value of the operating fan in different time periods;

[0019] Step 5: Control the overall air leakage rate of the system within the set range through the air leakage sealing component. Collect the flue operation parameters in real time through the sintering endpoint control module and determine the sintering endpoint position. Adjust the sintering machine travel speed and fan pressure in a coordinated manner to stabilize the sintering endpoint in the set area.

[0020] Preferably, in step four, the entire sintering process is divided into an ignition and combustion zone, a material layer preheating zone, a high-temperature reaction zone, and a finished product cooling zone according to the operation time; wherein the negative pressure of the system in the ignition and combustion zone is controlled at 7.4-9.6 kPa, the negative pressure of the system in the material layer preheating zone is controlled at 10.4-13.6 kPa, the negative pressure of the system in the high-temperature reaction zone is controlled at 13.9-17.5 kPa, and the negative pressure of the system in the finished product cooling zone is controlled at 9.4-12.6 kPa.

[0021] Preferably, in step five, when the sintering endpoint is determined to be ahead of schedule, the system negative pressure is reduced by 0.28-0.52 kPa, and the sintering machine travel speed is reduced by 0.15-0.35 m / min; when the sintering endpoint is determined to be behind schedule, the system negative pressure is increased by 0.28-0.52 kPa, and the sintering machine travel speed is increased by 0.15-0.35 m / min, so that the sintering endpoint is stabilized within the range of the second to third wind boxes from the end of the machine.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] 1. This invention uses a flue gas flow equalization device, with adjustable connecting equalization valves and adjusting baffles in each air box, to finely adjust the negative pressure difference between the two sides of the flue, so that the air volume of a single fan can evenly cover the entire sintering table. This completely eliminates the problems of uneven air volume on both sides and uneven lateral sintering of the material layer when a single fan is running. It ensures that the material layer receives uniform ventilation conditions from top to bottom and from left to right, thereby avoiding the phenomenon of local underfill and frequent deviation of the sintering endpoint, and ensuring the stability of the sinter quality.

[0024] 2. This invention employs optimized proportioning and a two-stage mixing and granulation process in the raw material preparation stage, strictly controlling the moisture content and particle size distribution of the mixture to achieve a high proportion of fine particles. This reduces the ventilation resistance of the thick material layer from the source, allowing the airflow to penetrate the nearly one-meter-thick material layer more smoothly even with only one fan supplying air. This reduces the problem of incomplete combustion in the middle and lower parts caused by excessive resistance, and also reduces the power waste caused by the fan being forced to operate at high frequency to overcome resistance, achieving a significant energy-saving effect.

[0025] 3. In this invention, a coarser base material is laid on the trolley grate, followed by a mixture. Simultaneously, three sets of adjustable loosening teeth are inserted into the material layer during the material distribution process to loosen it. Finally, a flat material drag plate is used to level the material surface. This effectively prevents the material from compacting and caking during the accumulation process, maintains good air permeability inside the material layer, and allows the limited exhaust volume to be more fully applied to the entire material layer, further improving the uniformity of sintering and production efficiency.

[0026] 4. This invention divides the entire sintering process into four zones: ignition and combustion, material layer preheating, high-temperature reaction, and finished product cooling. Each zone outputs a different negative pressure value, breaking through the limitations of traditional constant pressure operation. In the initial stage of ignition, excessive negative pressure is avoided to prevent heat loss. During the high-temperature reaction period, sufficient oxygen is provided to ensure a full reaction. During the cooling period, the pressure is appropriately reduced to reduce ineffective energy consumption. This not only improves the sintering quality but also reduces the overall power consumption.

[0027] 5. This invention achieves a very low overall air leakage rate by comprehensively sealing key air leakage points with high-temperature resistance, greatly improving the utilization rate of effective air volume and alleviating the contradiction of insufficient air volume of a single fan. With the help of sensors installed in the flue, the operating data is collected in real time and the integrated control module automatically determines the position of the sintering endpoint. Then, the traveling speed of the sintering machine and the air pressure parameters of the fan are adjusted in linkage to keep the sintering endpoint locked in the designated air box area at the tail of the machine. This effectively suppresses endpoint drift caused by fluctuations in the operating conditions of a single fan and ensures the continuous and stable production process. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the connection structure between the operating flue and the air box of the present invention;

[0029] Figure 2 This is a schematic diagram of the flue gas airflow balancing structure for single-fan operation according to the present invention;

[0030] Figure 3 This is a time-segmented negative pressure variation trend curve of a single fan according to the present invention;

[0031] Figure 4 This is a schematic diagram of the integrated structure of the double-layer loose fabric of the present invention.

[0032] In the diagram: 1. Sintering trolley; 2. Air box; 3. Air duct; 4. Air box butterfly valve; 5. Flue; 6. Adjusting baffle; 7. Flue isolation valve; 8. Adjustable connecting equalizing valve; 9. Running fan; 10. Stopped fan; 11. Trolley grate; 12. Bottom layer of paving material; 13. Upper layer of mixed material; 14. Liftable loose teeth; 15. Multi-roller distributor; 16. Leveling mechanism; 17. Leveling slide; 18. Mixed material; 19. Pipeline resistance. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] To address the problems of insufficient airflow, uneven airflow distribution, large fluctuations in operating conditions, poor product quality, and high energy consumption in existing thick-layer sintering processes, this embodiment provides the following technical solution:

[0035] A sintering device for a thick material layer with a single fan operation in a dual-fan layout sintering unit is disclosed. The device consists of six parts: a flue airflow equalization device, a raw material mixing and batching device, a double-layer loose material distribution device, a single fan air pressure regulation device, a system-wide air leakage sealing component, and a sintering endpoint linkage control device.

[0036] Combination Figure 1-2 As shown, the flue gas flow equalization device is used to achieve uniform air volume distribution under single fan operation conditions. It is arranged in the original air duct structure, which includes two main exhaust fans connected in parallel. Each main exhaust fan is connected to the end of two flues 5 respectively. A flue isolation valve 7 is installed at the inlet and outlet of each main exhaust fan, and an adjustable connecting equalization valve 8 is installed between the two flues 5 to connect them.

[0037] Multiple sets of air boxes 2 are arranged in sequence below the sintering trolley 1. Each set of air boxes 2 is equipped with an independent air box butterfly valve 4 at its outlet. The air boxes 2 are connected to one of the flues 5 through air ducts 3. The connection between the air ducts 3 and the flues 5 is either symmetrical or asymmetrical. Each set of air boxes 2 is equipped with an independently adjustable baffle 6 in the air duct 3. The flues 5 themselves have inherent resistance along the line.

[0038] When both main exhaust fans are operating normally, the flue isolation valve 7 remains fully open and exhausts air synchronously, jointly providing negative pressure power to the sintering material layer to meet the production needs of large-capacity, thick material layers. When the unit switches to single-fan operation mode, the flue isolation valve 7 corresponding to the stop fan 10 in the main exhaust fan remains fully closed, achieving physical isolation between the stop fan and the flue 5 to prevent air leakage; the flue isolation valve 7 corresponding to the running fan 9 remains fully open to ensure unobstructed exhaust passage.

[0039] Open the adjustable connecting equalization valve 8 and adjust its opening to initially balance the air pressure difference between the two flues 5; each adjusting baffle 6 can be finely adjusted to compensate for the air volume deviation caused by the resistance 19 along the pipeline, and finally stabilize the negative pressure ratio of the two flues 5 in the range of 1.04-1.22, so that the air volume deviation of each air box 2 of the whole machine is controlled within ±8%, eliminating the defect of transverse air imbalance when a single fan is running from the root, and realizing the uniform air volume coverage of the sintering machine table by a single fan.

[0040] Combination Figure 4 As shown, the double-layer loose material feeding device is set directly above the sintering trolley 1. The feeding end of the double-layer loose material feeding device corresponds to the discharging end of the raw material mixing and batching device. The bottom material feeding unit, multi-roller feeder 15, liftable loose teeth 14 and flat material mechanism 16 are arranged sequentially along the trolley's traveling direction.

[0041] Specifically, the bottom material laying unit lays sintered return ore with a particle size of 10-20mm on the surface of the trolley grate 11 to form a bottom material layer 12 with a thickness of 84-106mm; the multi-roller material distributor 15 lays the mixed material 18 on top of the bottom material to form an upper mixed material layer 13; the liftable loosening teeth 14 are divided into upper, middle and lower groups, and the insertion depth can be adjusted according to the total thickness of the material layer, and the material is loosened simultaneously during the material laying process to avoid the material from being compacted and caking; the material leveling mechanism 16 is equipped with a material leveling slide 17 at the rear end, which makes slight contact with the surface of the material layer to level the total material layer height to 800-920mm.

[0042] The raw material mixing and batching device sequentially includes a batching unit, a primary mixer, and a secondary mixer. The batching unit weighs and mixes the ore, quicklime, limestone, dolomite, solid fuel, and return ore according to a set mass ratio, and feeds them into the primary mixer for initial mixing. The primary mixer has a built-in preliminary humidification spray component to control the moisture content of the mixture 18 to 5.5%-6.0%. The secondary mixer has a built-in atomizing spray water replenishment component to precisely control the amount of water replenished, stabilizing the final moisture content of the mixture 18 at 6.0%-6.5%. The two-stage mixing and synergistic granulation ensures that the proportion of particles with a diameter of 2.7-8.1mm in the material is not less than 64.5%, optimizing the air permeability of the material layer from the source.

[0043] Combination Figure 3 As shown, the single-fan air pressure control device is electrically connected to the operating fan 9 and has a built-in time-sharing air pressure control module. Taking the total time of the trolley from the ignition position to the sintering endpoint as the cycle, the entire sintering process can be divided into four stages: ignition and combustion zone, material layer preheating zone, high-temperature reaction zone, and finished product cooling zone. Correspondingly, different stepped fan operating frequencies and system negative pressure set values ​​are output. In the ignition and combustion zone, material layer preheating zone, and high-temperature reaction zone, the negative pressure curve shows an upward trend, and gradually declines in the finished product cooling zone. It accurately matches the resistance characteristics and oxygen supply requirements of the material layer at different stages, breaking through the limitations of traditional constant negative pressure control and realizing dynamic matching of negative pressure parameters with the sintering process.

[0044] The air leakage sealing components of the entire system are respectively set at key air leakage points such as the gaps of the trolley side plate, the splicing of the trolley grate plate 11, the flexible connection section of the air box 2, and the flange interface of the flue 5. High temperature resistant sealing materials are used for sealing treatment. With the help of a routine inspection mechanism, the overall air leakage rate of the entire sintering system can be controlled at 11% or below, thereby improving the effective air volume utilization rate.

[0045] The sintering endpoint linkage control device consists of a negative pressure sensor, an exhaust gas temperature sensor, an exhaust gas oxygen content sensor, and an integrated control module in the flue 5. The integrated control module collects operating parameters in real time and determines the sintering endpoint position, and adjusts the sintering machine travel speed and main exhaust fan pressure parameters in linkage to stably limit the sintering endpoint to the designated air box 2 area at the tail of the machine.

[0046] Based on the above-mentioned device, the present invention performs the thick-layer sintering process according to the following steps when only one main exhaust fan of the dual-fan unit is operating:

[0047] Step 1: Balanced airflow adjustment in the flue

[0048] Select one main exhaust fan to start operation, and shut down the other main exhaust fan and close its inlet and outlet flue isolation valve 7 to complete physical isolation;

[0049] Open the adjustable communication equalization valve 8, and adjust the opening degree of the adjustable communication equalization valve 8 according to the real-time negative pressure data of the flue 5.

[0050] Adjust the opening of the regulating baffle 6 of each air box 2 one by one. For the air box 2 corresponding to the flue 5 with high resistance, open the regulating baffle 6 appropriately, and close the regulating baffle 6 appropriately on the side with low resistance. Finally, keep the negative pressure ratio of the flue 5 on the left and right sides in the range of 1.04-1.22, and the air volume difference of each air box 2 of the whole machine does not exceed 8%.

[0051] Step 2: Optimization and formulation of sintering raw material properties

[0052] Sintering raw materials are configured according to the following mass percentages: 55%-60% blended ore, 3.6%-4.5% quicklime, 2.2%-3.0% limestone, 3.8%-4.5% dolomite, 3.5%-4.3% solid fuel, and 27%-40% recycled ore;

[0053] The prepared raw materials are fed into a primary mixer for initial mixing and humidification, and the moisture content of the primary mixer output is controlled to be 5.5%-6.0%.

[0054] It is then fed into a secondary mixer, where water is precisely replenished using an atomized spray method to control the final output moisture content to remain stable at 6.0%-6.5%.

[0055] After two-stage mixing and granulation, the proportion of particles with a diameter of 2.7-8.1mm in the material is no less than 64.5%, which reduces the ventilation resistance of the thick material layer from the source.

[0056] Step 3: Double-layer loose fabric operation

[0057] After the trolley moves to the material placement station, the first step is for the base material placement unit to lay sintered return ore with a particle size of 10-20mm on the trolley grate 11 as the base material, with the laying thickness controlled at 84-106mm.

[0058] The multi-roller spreader 15 lays the mixed material 18 on top of the base material. During the spreading process, the upper, middle and lower three sets of lifting and loosening teeth 14 are inserted into the material layer simultaneously to loosen the material and prevent the material from being compacted and caking.

[0059] The leveling mechanism 16 uses a leveling slide 17 to level the material surface, controlling the total thickness of the base material and the mixed material 18 to be 800-920mm.

[0060] Step 4: Dynamic matching of wind pressure for single fans across different time periods

[0061] Combination Figure 3 The negative pressure control curve divides the entire sintering process from the ignition point to the sintering endpoint into four operating zones. Based on the material layer resistance characteristics of each zone, the operating frequency of the fan 9 and the system negative pressure are dynamically adjusted.

[0062] The ignition and combustion zone corresponds to an operation time of 0-2.6 minutes. The system negative pressure is controlled at 7.4-9.6 kPa to ensure stable ignition of the surface fuel and prevent excessive negative pressure from taking away surface heat and causing ignition failure.

[0063] The preheating zone of the material layer corresponds to an operation time of 2.6-7.2 minutes. The negative pressure of the system is controlled at 10.4-13.6 kPa. The exhaust volume is gradually increased to promote the transfer of heat to the middle and lower parts of the material layer.

[0064] The high-temperature reaction zone corresponds to an operation time of 7.2-19.2 minutes. The system negative pressure is controlled at 13.9-17.5 kPa to provide sufficient oxygen supply to ensure the sintering reaction proceeds fully. When the material layer thickness is not less than 900 mm, the negative pressure value in the high-temperature reaction zone is biased towards the upper limit of the zone to offset the additional resistance of the thick material layer.

[0065] The finished product cooling zone corresponds to an operation time of 19.2 minutes until the sintering endpoint. The system negative pressure is controlled at 9.4-12.6 kPa, and the exhaust volume is appropriately reduced to minimize ineffective energy consumption.

[0066] Step 5: System-wide air leakage control

[0067] Before production, key air leakage points such as the gaps in the side plates of the trolley, the splicing points of the trolley grate 11, the flexible connection section of the air box 2, and the flange interface of the flue 5 are sealed with high-temperature resistant sealing materials. During the production process, on-site air leakage inspections are carried out every 1.8-2.2 hours to promptly seal any new air leakage points, ensuring that the overall air leakage rate of the entire sintering system remains stable at 11% or below, thereby maximizing the utilization rate of effective air volume.

[0068] Step Six: Sintering Endpoint Control

[0069] The system uses sensors to collect real-time operating parameters such as negative pressure in flue 5, exhaust gas temperature, and oxygen content in the flue gas to determine the sintering endpoint. When the monitoring determines that the sintering endpoint is ahead of schedule, the system negative pressure is reduced by 0.28-0.52 kPa, and the sintering machine speed is reduced by 0.15-0.35 m / min. When the system determines that the sintering endpoint is behind schedule, the system negative pressure is increased by 0.28-0.52 kPa, and the sintering machine speed is increased by 0.15-0.35 m / min. Through the linkage adjustment of air pressure and machine speed, the sintering endpoint is always controlled within the range of the second to third air box from the end of the machine.

[0070] Three embodiments are provided below, as detailed below:

[0071] Example 1

[0072] This embodiment is applied to 360m 2 For a sintering unit with dual fans in parallel operation, with a single fan running, the thickness of the base material + mixed material 18 layers is set at 850mm. The specific operation process is as follows:

[0073] Flue 5 airflow balance adjustment: Close the flue isolation valve 7 of the stop fan 10, adjust the adjustable connecting balance valve 8 and the baffles of each air box 2, the negative pressure ratio of the two flues 5 is 1.11, and the maximum deviation of the whole unit air volume is 6.8%.

[0074] Optimization and blending of sintering raw materials: Raw material mass ratio: 55.5% iron-containing raw materials, 4.0% quicklime, 2.1% limestone, 4.2% dolomite, 3.9% solid fuel, and 30.3% recycled ore; after primary mixing, the moisture content is 5.8%, and the material mixing time is 5.3 min; after secondary mixing and atomization water replenishment, the final moisture content is 6.3%, and the proportion of particles with a diameter of 2.4-8.1 mm is 67.2%.

[0075] Double-layer loose material laying operation: The base material is 10-20mm return ore with a thickness of 88mm; the main material layer of the mixed material is 762mm; the leveling mechanism 16 has an operating height of 860mm, and three sets of loose teeth work throughout the process.

[0076] Dynamic matching of wind pressure for a single fan in different time periods: negative pressure of 8.1 kPa in the ignition zone; gradually increasing to 11.7 kPa in the material layer preheating zone; maintaining a stable 14.7 kPa in the high-temperature reaction zone; and lowering to 10.4 kPa in the finished product cooling zone.

[0077] System-wide air leakage control: After completing the treatment of each sealing point, the overall air leakage rate of the system is 10%, and inspections are carried out at the prescribed frequency.

[0078] Sintering endpoint linkage control: Real-time collection of operating data stabilizes the sintering endpoint at position 2 of the third-to-last air box at the tail of the machine, and fine-tunes the equipment operating parameters as needed.

[0079] The operating indicators of this embodiment are as follows: sinter drum strength 82.1%, return rate 6.2%, power consumption per unit area decreased by 9.3%, material layer sintering is uniform, and there is no significant fluctuation in operating conditions.

[0080] Example 2

[0081] The equipment unit in this embodiment is the same as that in Embodiment 1, with the material layer thickness set to 880mm. The specific operation process is as follows:

[0082] Flue 5 airflow balance adjustment: After adjustment, the negative pressure ratio of the two sides of flue 5 is 1.14, and the overall air volume deviation is 6.3%.

[0083] Optimization and blending of sintering raw materials: Raw material mass ratio: 55.7% iron-containing raw materials, 4.3% quicklime, 1.8% limestone, 4.1% dolomite, 4.0% solid fuel, and 30.1% recycled ore; primary mixing moisture content 5.7%, mixing time 5.3 min; secondary mixing final moisture content 6.42%, qualified particle size percentage 65.3%.

[0084] Double-layer loose fabric operation: the base material is laid with a thickness of 94mm, the total material layer is 905mm, and the leveling mechanism 16 has a height of 910mm.

[0085] Dynamic matching of wind pressure for a single fan in different time periods: negative pressure of 8.8 kPa in the ignition zone, 12.3 kPa in the preheating zone, 16.3 kPa in the high-temperature reaction zone, and 11.3 kPa in the cooling zone.

[0086] Overall system air leakage control: The overall system air leakage rate is 8.4%.

[0087] Sintering endpoint linkage control: Multi-parameter linkage adjustment, the sintering endpoint is stabilized at the second-to-third air box from the end of the machine.

[0088] The operating indicators of this embodiment are: sinter drum strength of 82.7%, return rate of 6.5%, power consumption per unit area decreased by 10.7%, and the heat storage and energy saving effect of the thick material layer is significant.

[0089] Example 3

[0090] This embodiment uses a maximum material layer configuration, with a material layer thickness set at 920mm. The specific operation process is as follows:

[0091] Flue 5 airflow balance adjustment: fine adjustment of the adjustable connecting balance valve 8 and the baffles of each air box 2, the overall air volume deviation is controlled within 6.9%.

[0092] Optimization and blending of sintering raw materials: Increase the ratio of quicklime to recycled ore. Raw material quality ratio: 47.9% iron-containing raw materials, 4.5% quicklime, 1.5% limestone, 3.8% dolomite, 4.2% solid fuel, and 38.1% recycled ore; the final moisture content of the secondary mixture is 6.7%, and the particle size distribution meets the process requirements.

[0093] Double-layer loose fabric operation: the base material is 105mm thick, the total material layer is 920mm, and the material is loosened throughout the process.

[0094] Dynamic matching of wind pressure for a single fan in different time periods: negative pressure of 9.5 kPa in the ignition zone, 13.5 kPa in the preheating zone, 17.5 kPa in the high-temperature reaction zone, and 12.5 kPa in the cooling zone.

[0095] System-wide air leakage control and sintering endpoint linkage regulation: Strengthen surface anti-caking treatment and air leakage inspection, dynamically correct operating parameters, and eliminate raw material and over-burning phenomena.

[0096] The operating indicators of this embodiment are: sinter drum strength of 81.8%, return rate of 7.0%, and power consumption per unit area reduced by 12.0%, which can achieve long-term continuous operation of the extreme thick material layer.

[0097] Working principle: When the dual-fan sintering unit switches to single-fan operation mode, firstly, the flue isolation valve 7 corresponding to the stop fan 10 is kept fully closed to achieve physical isolation between the stop fan and the flue 5, while the flue isolation valve 7 corresponding to the running fan 9 is kept fully open to ensure unobstructed airflow. The adjustable connecting equalization valve 8 is opened and its opening is adjusted to initially balance the air pressure difference between the two flues 5. Then, the opening of the adjusting baffle 6 in each air box 2 is finely adjusted to compensate for the airflow deviation caused by the resistance along the pipeline, so that the negative pressure ratio of the two flues 5 is stabilized in the range of 1.04-1.22, and the airflow deviation of each air box 2 is controlled within ±8%, achieving uniform airflow coverage of the sintering trolley 1 by the single fan.

[0098] The raw material mixing and batching device weighs and mixes ore, quicklime, limestone, dolomite, solid fuel and return ore according to the set ratio through the batching unit, and sends them to the primary mixer for initial mixing and adjusts the moisture content to 5.5%-6.0%. Then, the secondary mixer atomizes and sprays water to make the final moisture content stable at 6.0%-6.5%. After two-stage mixing and granulation, the proportion of particles with a diameter of 2.7-8.1mm in the material is not less than 64.5%, which reduces the ventilation resistance of the thick material layer from the source.

[0099] The double-layer loosening and spreading device begins operation: the bottom material spreading unit lays sintered return ore with a particle size of 10-20mm on the surface of the trolley grate 11 to form a bottom layer 12 with a thickness of 84-106mm; the multi-roller spreader 15 lays the mixed material 18 on top of the bottom material to form an upper layer 13; the liftable loosening teeth 14 are divided into upper, middle and lower groups and are inserted into the material layer simultaneously to loosen the material and prevent the material from being compacted and caking; the flat material drag plate 17 at the rear end of the leveling mechanism 16 contacts the surface of the material layer and flattens the total material layer height to 800-920mm.

[0100] During the sintering process, the single-fan air pressure control device is electrically connected to the running fan 9. The entire sintering process is divided into four stages: ignition and combustion zone, material layer preheating zone, high-temperature reaction zone, and finished product cooling zone, based on the total time it takes for the trolley to travel from the ignition position to the sintering endpoint. Different stepped fan operating frequencies and system negative pressure settings are output accordingly.

[0101] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0102] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. A single-fan operation thick-layer sintering device for a dual-fan sintering unit, comprising two main exhaust fans connected in parallel, two flues (5), multiple air boxes (2), and a sintering trolley (1), characterized in that, Also includes: The flue airflow equalization device consists of a flue isolation valve (7) located at the inlet and outlet of each main exhaust fan, an adjustable connecting equalization valve (8) located between two flues (5), and an adjusting baffle (6) located in the air duct (3) of each air box (2). The double-layer loose material feeding device is located directly above the sintering trolley (1). The feeding end of the double-layer loose material feeding device corresponds to the discharging end of the raw material mixing and batching device. Along the traveling direction of the trolley (1), the bottom material feeding unit, the multi-roller feeder (15), the liftable loose teeth (14) and the flat material mechanism (16) are arranged in sequence. The raw material mixing and batching device consists of a batching unit, a primary mixer and a secondary mixer connected in sequence. The primary mixer is equipped with a preliminary humidification spray component, and the secondary mixer is equipped with an atomizing spray water replenishment component. A single-fan air pressure control device is electrically connected to the operating fan (9) and has a built-in time-sharing air pressure control module; The entire system air leakage sealing assembly uses high-temperature resistant sealing materials and is placed at the air leakage points of the joints in the sintering system. The sintering endpoint linkage control device consists of a negative pressure sensor, a waste gas temperature sensor, a waste gas oxygen content sensor and an integrated control module connected to each sensor, all located in the flue (5). The output of the integrated control module is connected to the control terminals of the sintering machine drive mechanism and the main exhaust fan, respectively.

2. The thick-layer sintering device for a dual-fan sintering unit with single-fan operation according to claim 1, characterized in that, The adjustable connecting equalization valve (8) connects two flues (5), and the adjusting baffle (6) is independently set in the air duct (3) of each air box (2) and its opening degree can be adjusted independently.

3. The thick-layer sintering device for a dual-fan sintering unit with single-fan operation according to claim 1, characterized in that, The base material spreading unit is located at the front end of the trolley (1) in the direction of travel. The multi-roller spreader (15) is located behind the base material spreading unit. The liftable loose teeth (14) are divided into three groups: upper, middle and lower, and are set between the multi-roller spreader (15) and the leveling mechanism (16).

4. The thick-layer sintering device for a dual-fan sintering unit with single-fan operation according to claim 1, characterized in that, The time-segmented wind pressure control module is built into the control circuit of the operating fan (9) and is used to output the stepped fan operating frequency and system negative pressure setting value according to different time intervals of the sintering process.

5. A thick-layer sintering device for a dual-fan sintering unit with single-fan operation according to claim 1, characterized in that, The high-temperature resistant sealing material is used to fill, but is not limited to, the gaps in the side plates of the trolley (1), the joints of the trolley grate (11), the flexible connection section of the air box (2), and the flange interface of the flue (5), and forms a sealing layer at each filling location.

6. The thick-layer sintering device for a dual-fan sintering unit with single-fan operation according to claim 1, characterized in that, Each of the aforementioned bellows (2) outlets is also equipped with an independent bellows butterfly valve (4).

7. A thick-layer sintering device for a dual-fan sintering unit with single-fan operation according to claim 1, characterized in that, The rear end of the leveling mechanism (16) is fixed with a leveling slide (17), which is in contact with the surface of the upper mixed material layer (13).

8. A method for sintering thick material layers in a dual-fan sintering unit with single-fan operation, implemented based on the dual-fan sintering unit with single-fan operation thick material layer sintering apparatus according to any one of claims 1-7, characterized in that, Includes the following steps: Step 1: Select a main exhaust fan as the operating fan (9) and put it into operation. Close the flue isolation valve (7) at the inlet and outlet of the stop fan (10) to complete the physical isolation. Open and adjust the opening of the adjustable connecting equalization valve (8), and adjust the opening of the adjusting baffle (6) in each air duct (3) one by one to keep the negative pressure ratio of the two flues (5) in the range of 1.04-1.

22. Step 2: After weighing the raw materials according to the set mass ratio through the batching unit, the raw materials are sent to the primary mixer. After preliminary mixing and humidification, the raw materials are sent to the secondary mixer for atomization and water replenishment to complete the granulation of the mixture (18). Step 3: The base material is laid on the surface of the trolley grate (11) by the base material laying unit to form a base material layer (12). Then, the mixed material (18) is laid on the base material layer (12) by the multi-roller material spreader (15) to form a mixed material layer (13). During the material laying process, the material is loosened by the liftable loosening teeth (14). Finally, the total material layer thickness is flattened to 800-920mm by the flat material slide (17) of the flat material mechanism (16). Step 4: Divide the entire sintering process into multiple operating zones using the single-fan air pressure control module, and adjust the system negative pressure value of the operating fan (9) in different time periods; Step 5: Control the overall air leakage rate of the system within the set range through the air leakage sealing component. Collect the operating parameters of the flue (5) in real time through the sintering endpoint control module and determine the sintering endpoint position. Adjust the sintering machine travel speed and fan pressure in a linkage manner to stabilize the sintering endpoint in the set area.

9. A thick-layer sintering device for a dual-fan sintering unit with single-fan operation according to claim 8, characterized in that, In step four, the entire sintering process is divided into an ignition and combustion zone, a material layer preheating zone, a high-temperature reaction zone, and a finished product cooling zone according to the operation time. The negative pressure of the system in the ignition and combustion zone is controlled at 7.4-9.6 kPa, the negative pressure of the system in the material layer preheating zone is controlled at 10.4-13.6 kPa, the negative pressure of the system in the high-temperature reaction zone is controlled at 13.9-17.5 kPa, and the negative pressure of the system in the finished product cooling zone is controlled at 9.4-12.6 kPa.

10. A thick-layer sintering device for a dual-fan sintering unit with single-fan operation according to claim 8, characterized in that, In step five, when the sintering endpoint is determined to be ahead of schedule, the negative pressure of the system is reduced by 0.28-0.52 kPa, and the speed of the sintering machine is reduced by 0.15-0.35 m / min; when the sintering endpoint is determined to be behind schedule, the negative pressure of the system is increased by 0.28-0.52 kPa, and the speed of the sintering machine is increased by 0.15-0.35 m / min, so that the sintering endpoint is stabilized within the range specified by the tail wind box (2).

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