A system and method for preventing and treating zinc pot slagging of high-aluminum zinc-aluminum-magnesium galvanizing line

Abstract

This invention relates to the field of hot-dip galvanizing technology for strip steel, specifically to a system and method for preventing slag formation in the zinc pot of a high-alumina-zinc-alumina-magnesium galvanizing line. On one hand, this invention precisely controls the temperature of the strip steel entering the pot by using an atmosphere barrier and an online slag-removing, stabilizing, and rapidly cooling device to prevent high-temperature strip steel from exacerbating iron leaching. On the other hand, it removes iron powder impurities from the strip steel surface through deep scrubbing, reducing the introduction of iron sources from the front end. Furthermore, it constructs a unified circulating flow field for the zinc liquid through high-power electromagnetic agitation, ensuring that the generated fine zinc slag remains in a suspended state and is dynamically carried out by the continuous operation of the strip steel, effectively solving the problem of zinc slag retention and accumulation. Simultaneously, it employs a collaborative closed-loop control algorithm, adaptable to the production conditions of different strip steel specifications and coated products, significantly extending the continuous operation cycle of the zinc pot while ensuring coating quality, reducing downtime for slag removal and equipment maintenance, and lowering labor and operation costs.

Description

Technical Field

[0001] This invention relates to the field of hot-dip galvanizing technology for strip steel, and specifically to a system and method for preventing slag formation in the zinc pot of a high-alumina-zinc-alumina-magnesium galvanizing line. Background Technology

[0002] In continuous hot-dip galvanizing production, the problem of bottom slag and edge slag in the zinc bath has long been a technological challenge. This problem is particularly severe for production lines producing high-alumina zinc-aluminum-magnesium coatings (such as those with a composition of 55% Al-1.6% Si-43% Zn-0.4% Mg, operating at approximately 600℃). The high temperature of the zinc bath causes the zinc to volatilize violently, generating a large amount of zinc ash (mainly ZnO). This zinc ash flows with the protective gas in the annealing furnace and easily adheres to and clogs the heat exchange fins of the rapid cooler (cooler) located at the end of the annealing furnace, causing a sharp drop in its cooling efficiency.

[0003] The loss of cooling capacity prevents the temperature of the strip entering the zinc pot (PotEntryTemperature, PET) from being effectively reduced, often remaining higher than the temperature of the molten zinc. The high-temperature strip becomes a continuous heat source, transferring a large amount of heat to the molten zinc. This leads to: 1) the zinc pot induction heaters needing to operate at low power for extended periods to balance the heat, resulting in insufficient electromagnetic stirring (EMS) to suspend the generated zinc dross and allow it to be carried away by the strip; 2) the high temperature exacerbates the dissolution of iron elements from the strip surface into the molten zinc, forming more zinc-iron alloy dross such as Fe2Al5.

[0004] The processes of "high PET → high iron leaching → excessive zinc dross generation" and "low EMS → weak dross discharge → zinc dross accumulation" are coupled, forming a vicious cycle. Accumulated zinc dross will: encroach on the effective volume of the zinc pot, affecting thermal stability; deteriorate the installation accuracy of equipment such as submerged rollers and stabilizing rollers, causing plate shape defects and uneven zinc layers; and in severe cases, encase the sensor coil, causing insulation damage, grounding short circuits, or even coil burnout, threatening production safety. Traditional solutions, such as periodic manual dross removal and fine-tuning of process parameters, are merely passive measures that cannot break the vicious cycle, and they also affect production continuity and increase maintenance costs. Summary of the Invention

[0005] The technical problem to be solved by this invention is to provide a system and method for preventing slagging in the zinc pot of a high-alumina-zinc-alumina-magnesium galvanizing line, which can simultaneously solve the two fundamental problems of "excessive iron input" and "zinc slag retention and accumulation", thereby eradicating the problem of zinc pot slagging in high-alumina-zinc-alumina-magnesium galvanizing line and ensuring long-term stable, efficient and low-cost operation of the production line.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A system for preventing slag buildup in a zinc pot on a high-alumina-zinc-aluminum-magnesium galvanizing line includes a cleaning section, an annealing furnace, and a zinc pot arranged sequentially along the strip processing direction; wherein, the rapid cooling section at the end of the annealing furnace is integrated with a strip entry temperature protection module 100, the cleaning section is equipped with a strip surface cleaning module 200, and the zinc pot is equipped with a zinc liquid dynamic purification module 300. The strip steel entry temperature protection module 100 is used to maintain the cooling efficiency of the rapid cooler in the rapid cooling section to limit the temperature of the strip steel entering the zinc pot. It includes an atmosphere isolation unit and an online active ash removal unit. The strip surface cleaning module 200 includes multiple pairs of dual active brush rollers installed in the cleaning section to remove oxides and iron powder residues from the strip surface, thereby reducing the source of iron input. The zinc liquid dynamic purification module 300 includes a high-power electromagnetic stirring device installed in the zinc pot, which drives the zinc liquid to circulate, forms sufficient shear force to prevent zinc dross particles from settling, and allows suspended zinc dross to be captured by the moving strip surface and carried out of the zinc pot. The strip steel temperature protection module 100, the strip steel surface cleaning module 200, and the zinc liquid dynamic purification module 300 are all electrically connected to the system controller.

[0007] Preferably, the atmosphere isolation unit includes a protective gas inlet and an exhaust outlet independently disposed on the furnace shell of the rapid cooling section, and the inlet is supplied with a protective gas with adjustable gas flow rate and pressure to form a slightly positive pressure atmosphere barrier in the rapid cooling section, so as to prevent the zinc-containing ash gas flow from the soaking section and slow cooling section of the annealing furnace from entering the rapid cooler.

[0008] Preferably, the online active dust removal unit includes a purge nozzle array and corresponding electrically controlled valve arranged on the upper air side of the heat exchanger plate group of the fast cooler, as well as pressure sensors located at the inlet and outlet of the fast cooler. The purge nozzle array is used to spray high-pressure nitrogen gas to remove zinc ash adhering to the heat exchanger plate of the fast cooler.

[0009] Preferably, the online active dust removal unit uses nitrogen as the purging medium in its purging nozzle array, and is triggered according to a preset time period or based on the pressure difference signal from the pressure sensors before and after the rapid cooler to perform online nitrogen purging.

[0010] Preferably, the dual active brush roller group is symmetrically arranged along both sides of the strip steel in the cleaning section, and the brush rollers on both sides rotate in opposite directions at a linear speed of 1.2 to 1.5 times the speed of the strip steel, so that the brush rollers and the surface of the strip steel always maintain a preset brushing shear force, so as to effectively remove embedded iron powder from the surface of the strip steel.

[0011] Preferably, the high-power electromagnetic stirring device operates stably at rated high power in a "dual-coil mode", maintaining an operating power of not less than 500KW during the production process.

[0012] Based on the same inventive concept, this invention also provides a method for preventing slagging in zinc pots of high-alumina-zinc-alumina-magnesium galvanizing lines. This method employs the system described above for preventing slagging in zinc pots of high-alumina-zinc-alumina-magnesium galvanizing lines, and mainly includes the following steps: S1, Iron input inhibition: S1.1 Precise control of strip steel entering the pot: The strip steel entering the pot temperature protection module is activated, and protective gas is introduced into the rapid cooling section through the atmosphere isolation unit to maintain a slight positive pressure in the rapid cooling section, forming a reverse airflow barrier to prevent zinc ash-containing airflow from the upstream of the annealing furnace from entering the rapid cooler; at the same time, the zinc ash on the surface of the heat exchange plate is regularly removed by the online active ash removal unit to ensure the heat exchange efficiency of the rapid cooler is stable and to keep the temperature of the strip steel entering the zinc pot below the preset target value. S1.2 Deep cleaning of strip surface: Start the strip surface cleaning module, control the double active brush roller group to rotate in the opposite direction at a set speed ratio and maintain a stable pressing amount to continuously shear and brush the strip to remove residual iron powder, iron oxide scale and impurities on the strip surface, and reduce the total amount of iron elements entering the zinc liquid with the strip. S2, Dynamic removal of zinc dross: S2.1 Construction of longitudinal circulating flow field: The zinc liquid dynamic purification module is controlled to operate in dual-coil high-power mode to maintain rated high power output and form a longitudinal convection circulating flow field that runs through the entire zinc pot. S2.2 Continuous removal of suspended zinc dross: Under the action of strong electromagnetic stirring, the fine zinc dross particles generated in the zinc liquid are suspended in the zinc liquid; the suspended zinc dross that circulates with the zinc liquid to the strip immersion area comes into full contact with the continuously rising strip surface and is adsorbed, and leaves the zinc pot with the strip, thus realizing the continuous dynamic removal of zinc dross. S3, Parameter Coordination Closed-Loop Control The system controller collects operating parameters in real time and dynamically adjusts the protective gas flow rate according to changes in strip specifications, operating speed, and coating composition using a collaborative closed-loop control algorithm to maintain a stable anti-slagging effect.

[0013] Preferably, in step S1, the online active dust removal unit is started using a differential pressure trigger mode or a timed mode: when the differential pressure trigger mode is used, the differential pressure signal value of the pressure sensor at the inlet and outlet of the fast cooler is monitored in real time, and when the differential pressure signal value is ≥ the preset differential pressure threshold, the electronically controlled valve of the purging nozzle array is automatically opened to perform online nitrogen purging. When the timed mode is used, the electrically controlled valves of the purging nozzle array will automatically start and stop according to the preset time period.

[0014] Preferably, in step S2, the operating power of the zinc liquid dynamic purification module is maintained between 500kW and the rated upper limit of the equipment, so that the zinc liquid flow rate in the bottom area of ​​the zinc pot is not less than 0.3m / s, ensuring that zinc slag particles with a particle size ≤50μm are always in a suspended state.

[0015] Preferably, in step S3, the calculation formula for the cooperative closed-loop control algorithm is as follows:

[0016] In the formula, This refers to the volumetric flow rate of the protective gas under real-time operating conditions. The reference flow rate of protective gas corresponding to the production line's baseline operating conditions is determined by on-site thermal balance and furnace pressure calibration. These are the real-time strip running speed, strip thickness, and strip width, respectively. These are the strip speed, thickness, and width corresponding to the baseline working condition; This is the coating composition correction factor, which is determined based on the proportion of each element in the strip steel coating.

[0017] Compared with the prior art, the present invention has the following main advantages: 1. This invention inhibits iron input through two-way control of the inlet temperature and surface cleaning treatment: on the one hand, it stabilizes the cooling capacity of the rapid cooler by using an atmosphere barrier and online ash removal to precisely control the temperature of the strip steel entering the pot, thus avoiding the aggravation of iron dissolution by high-temperature strip steel; on the other hand, it removes iron powder impurities from the surface of the strip steel by deep washing, thereby reducing the introduction of iron sources from the front end and reducing the rate of zinc dross formation from the root. 2. This invention constructs an overall circulating flow field of zinc liquid through high-power electromagnetic stirring, which breaks the drawback of zinc dross settling and accumulating under traditional low-power operation. It keeps the generated fine zinc dross in a suspended state and achieves dynamic removal of zinc dross by means of continuous operation of strip steel. It can maintain the cleanliness of the inside of the zinc pot without stopping the machine to clean the dross, effectively solving the problem of zinc dross retention and accumulation. 3. The present invention adopts a collaborative closed-loop control algorithm, which can be adapted to the production conditions of different specifications of strip steel and coated products. Under the premise of ensuring coating quality, it significantly extends the continuous operation cycle of zinc pot, reduces the frequency of shutdown for slag removal and equipment maintenance, and reduces labor and operation and maintenance costs. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall system structure and process flow in an embodiment of the present invention; Figure 2 This is a schematic diagram of the atmosphere isolation unit and active ash removal unit of the strip steel entering the pot temperature protection module in an embodiment of the present invention. Figure 3 This is an overall flowchart of the prevention and control method in an embodiment of the present invention.

[0019] In the diagram: 100 - Strip steel temperature protection module, 200 - Strip steel surface cleaning module, 300 - Zinc liquid dynamic purification module. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0021] It should be noted that, depending on the implementation needs, the various steps / components described in this application can be broken down into more steps / components, or two or more steps / components or parts of the operation of steps / components can be combined into new steps / components to achieve the purpose of this invention.

[0022] In this invention, unless otherwise expressly specified and limited, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise expressly and specifically limited.

[0023] Example 1: This example provides a system for preventing slagging in zinc pots of high-alumina, zinc-alumina, and magnesium galvanizing lines, such as... Figures 1-2 As shown, it mainly includes: a strip steel entry temperature protection module 100, a strip steel surface cleaning module 200, and a zinc liquid dynamic purification module 300; The strip steel temperature protection module 100 is used to maintain the cooling efficiency of the rapid cooler in the rapid cooling section to limit the strip steel temperature entering the zinc pot, and ensure that the strip steel temperature (PET) entering the zinc pot is stably controlled at or below the working temperature of the zinc liquid (e.g., 600°C). It includes an atmosphere isolation unit and an online active dust removal unit. The strip surface cleaning module 200 includes multiple pairs of double active brush rollers installed in the cleaning section to remove oxides and iron powder residues from the strip surface, thereby reducing the source of iron input. The zinc liquid dynamic purification module 300 includes a high-power electromagnetic agitator installed in the zinc pot to drive the zinc liquid to circulate, generate sufficient shear force to prevent zinc dross particles from settling, and allow suspended zinc dross to be captured by the moving strip surface and carried out of the zinc pot. The strip steel temperature protection module 100, the strip steel surface cleaning module 200, and the zinc liquid dynamic purification module 300 are all electrically connected to the system controller.

[0024] In this embodiment, the atmosphere isolation unit includes a protective gas inlet and an exhaust outlet independently disposed on the furnace shell of the rapid cooling section. The inlet is supplied with a protective gas (such as high-purity nitrogen) with adjustable gas flow rate and pressure. This is used to form a relatively independent and controllable micro-positive pressure atmosphere barrier in the rapid cooling section to prevent zinc-containing ash gas flow from the soaking section and slow cooling section of the annealing furnace from entering the rapid cooler.

[0025] In this embodiment, an online active cleaning unit is installed for at least one rapid cooler (usually the cooler at the lowest position or in a dead zone of airflow) that is most prone to zinc ash blockage in the rapid cooling section. The online active cleaning unit includes a purge nozzle array and a corresponding electrically controlled valve arranged on the upper side of the heat exchange plate group of the rapid cooler, which is used to spray high-pressure nitrogen gas to remove zinc ash adhering to the heat exchange plate of the rapid cooler.

[0026] In this embodiment, the online active dust removal unit uses nitrogen as the purging medium for its purging nozzle array, and automatically starts and stops according to a preset time cycle (e.g., every 1-2 hours / time) or triggered by the differential pressure sensor signal conditions before and after the fast cooler to perform online nitrogen purging.

[0027] In this embodiment, the dual active brush roller group is symmetrically arranged along both sides of the strip steel in the cleaning section, and the brush rollers and the strip steel surface always maintain a preset brushing shear force to effectively remove embedded iron powder from the strip steel surface.

[0028] In this embodiment, the high-power electromagnetic stirring device operates stably at rated high power in "dual coil mode". During the production process, it maintains an operating power of not less than 500KW to provide sufficient electromagnetic stirring force (EMS). The strong alternating magnetic field generated by the high-power operation will induce a strong Lorentz force inside the zinc liquid, driving the zinc liquid to circulate and form sufficient shear force to prevent zinc dross particles from settling and to suspend and flow with the flow. Finally, some of them are captured by the moving strip surface and carried out of the zinc pot.

[0029] Example 2, based on the same inventive concept, also provides a method for preventing slagging in the zinc pot of a high-alumina-zinc-alumina-magnesium galvanizing line. This method employs the system described above for preventing slagging in the zinc pot of a high-alumina-zinc-alumina-magnesium galvanizing line. Figure 3 As shown, it includes the following steps: Step S1, Iron input suppression: S1.1: Activate the strip steel entry temperature protection module. A protective atmosphere barrier is established through the atmosphere isolation unit, and zinc ash is periodically removed using the online active ash removal unit, thereby ensuring that the rapid cooler has continuous and efficient cooling capacity and stably controlling the strip steel temperature (PET) entering the zinc pot at the set target of ≤600℃ (zinc liquid working temperature).

[0030] S1.2: Activate the strip surface cleaning module. The optimized dual active brush roller device performs high-intensity brushing on the strip surface to remove oxides and iron powder residues to the greatest extent.

[0031] Step S2, dynamic removal of zinc dross: S2.1: Control the zinc liquid dynamic purification module (zinc pot induction heating system) to operate in dual-coil, high-power mode, and set and maintain the heating power at a level of ≥500KW.

[0032] S2.2: Under the strong electromagnetic agitation (EMS) generated by high-power operation, intense convection is formed inside the molten zinc. Fine zinc dross particles generated in step S1, which could not be completely avoided, cannot settle to the bottom of the pot or adhere to the pot wall under this convection, but remain suspended and flow with the molten zinc. Some of the suspended zinc dross particles come into contact with the surface of the upward-moving strip under the influence of the flow field, are adhered to by it, and are eventually carried away from the zinc pot system, thus achieving continuous and dynamic removal of zinc dross.

[0033] Step S3, parameter coordinated closed-loop control: The system controller collects operating parameters in real time and dynamically adjusts the protective gas flow rate according to changes in strip specifications, operating speed, and coating composition using a collaborative closed-loop control algorithm to maintain a stable anti-slagging effect.

[0034] Furthermore, in step S1, the rapid cooler is periodically (every 1-2 hours) or purged online with nitrogen based on differential pressure sensor signal conditions.

[0035] Furthermore, in step S2, the operating power of the zinc liquid dynamic purification module is maintained between 500KW and its rated upper limit power.

[0036] Furthermore, in step S3, the calculation formula for the cooperative closed-loop control algorithm is as follows:

[0037] In the formula, This refers to the volumetric flow rate of the protective gas under real-time operating conditions. The reference flow rate of protective gas corresponding to the production line's baseline operating conditions is determined by on-site thermal balance and furnace pressure calibration. These are the real-time strip running speed, strip thickness, and strip width, respectively. These are the strip speed, thickness, and width corresponding to the baseline working condition; This is the coating composition correction factor, which is determined based on the proportion of each element in the strip steel coating.

[0038] Example 3: This example uses a high-alumina-zinc-alumina-magnesium (55%Al-1.6%Si-43%Zn-0.4%Mg) galvanizing line of Unit 108 in a cold rolling mill as an example to apply the prevention and control system and method of the present invention.

[0039] The zinc liquid in this production line operates at a temperature of 600℃. Before the upgrade, it was plagued by slag buildup in the zinc pot, with bottom slag thickness exceeding 400mm and edge slag being hard.

[0040] 1. System implementation and modification: 1) Strip steel inlet temperature protection module: Two Φ100mm holes are opened in the top of the furnace shell of the rapid cooling section of the annealing furnace, and high-purity nitrogen pipelines are connected as independent air inlets; an exhaust pipe is opened at the bottom of the rapid cooling section. The flow meter is used to adjust the pressure in this section to maintain a slight positive pressure of about 30Pa. Above the No. 5 rapid cooler located downstream of the airflow, eight nitrogen nozzles are evenly distributed along the width direction and connected to a programmable solenoid valve, which is set to automatically purge for 40 seconds every 2 hours of operation.

[0041] 2) Strip surface cleaning module: The No. 3 and No. 4 brush roller units in the cleaning section are changed from the original configuration of "one active brush roller + one passive rubber squeezing roller" to "double active brush roller (opposite)" configuration, and the brush roller line pressure is increased to 1.5 times the original design.

[0042] 3) Zinc liquid dynamic purification module: Thoroughly excavate and repair the refractory material cracks and insulation layer carbonization areas caused by zinc slag penetration on the upper coil of the zinc pot, and recast it with high-performance refractory material to restore its electrical performance to the new coil standard, ensuring that the two coils can be operated in parallel.

[0043] 2. Method execution control: 1) During production, first activate the independent nitrogen gas curtain in the rapid cooling section and adjust the flow rate to stabilize the slight positive pressure. The nitrogen purging program will run automatically.

[0044] 2) Start the cleaning section and ensure that the pressure and speed of the modified dual active brush rollers are within the set process range.

[0045] 3) The zinc pot induction heating system is switched to "dual coil" mode. In the automation system, the power setting value is locked at 520KW, and the system automatically maintains this power.

[0046] 4) Monitor the temperature of the strip steel entering the zinc pot (PET). Through the above measures, the PET temperature has been steadily reduced from 620-640℃ before the modification to 590-600℃.

[0047] 3. Implementation effect: Observe and evaluate after three months of continuous operation: 1) Slag control: The slag layer at the bottom of the zinc pot is stable at 150-200mm and is loose and flocculent, making it easy to remove daily; the hard edge slag on the side wall of the zinc pot and around the sensor has basically disappeared.

[0048] 2) Product quality: The installation accuracy of the submerged roll and stabilizing roll has been maintained for a long time, the strip shape qualification rate has increased from 89% to 96%, the standard deviation of zinc layer uniformity has been reduced by 30%, and the batch stable production of low-temperature annealed specialty steel has been successfully achieved.

[0049] 3) Operation and Costs: The temperature fluctuation range of the zinc pot was narrowed from ±10℃ to ±3℃. The average monthly zinc excess rate decreased from 14.7% to 13.15%. Based on the production capacity of this line, the cost per ton of steel decreased by approximately RMB 8.5, resulting in an annualized direct economic benefit of over RMB 1 million. No further equipment failures related to zinc slag occurred.

[0050] Furthermore, all parts of this application that are not described in detail are the same as or implemented using existing technology.

[0051] In summary: 1. This invention inhibits iron input through two-way control of the inlet temperature and surface cleaning treatment: on the one hand, it stabilizes the cooling capacity of the rapid cooler by using an atmosphere barrier and online ash removal to precisely control the temperature of the strip steel entering the pot, thus avoiding the aggravation of iron dissolution by high-temperature strip steel; on the other hand, it removes iron powder impurities from the surface of the strip steel by deep washing, thereby reducing the introduction of iron sources from the front end and reducing the rate of zinc dross formation from the root. 2. This invention constructs an overall circulating flow field of zinc liquid through high-power electromagnetic stirring, which breaks the drawback of zinc dross settling and accumulating under traditional low-power operation. It keeps the generated fine zinc dross in a suspended state and achieves dynamic removal of zinc dross by means of continuous operation of strip steel. It can maintain the cleanliness of the inside of the zinc pot without stopping the machine to clean the dross, effectively solving the problem of zinc dross retention and accumulation. 3. The present invention adopts a collaborative closed-loop control algorithm, which can be adapted to the production conditions of different specifications of strip steel and coated products. Under the premise of ensuring coating quality, it significantly extends the continuous operation cycle of zinc pot, reduces the frequency of shutdown for slag removal and equipment maintenance, and reduces labor and operation and maintenance costs.

[0052] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0053] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0054] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A system for preventing slagging in a zinc pot on a high-alumina, zinc-alumina, and magnesium-aluminum galvanized steel line, comprising a cleaning section, an annealing furnace, and a zinc pot arranged sequentially along the strip processing direction, characterized in that: The annealing furnace is equipped with a strip steel inlet temperature protection module (100) in the end rapid cooling section, a strip steel surface cleaning module (200) is installed in the cleaning section, and a zinc liquid dynamic purification module (300) is installed in the zinc pot. The strip steel inlet temperature protection module (100) is used to maintain the cooling efficiency of the rapid cooler in the rapid cooling section to limit the temperature of the strip steel entering the zinc pot. It includes an atmosphere isolation unit and an online active dust removal unit. The strip steel surface cleaning module (200) includes multiple pairs of double active brush rollers installed in the cleaning section to remove oxides and iron powder residues on the surface of the strip steel to reduce the source of iron input. The zinc liquid dynamic purification module (300) includes a high-power electromagnetic stirring device installed in the zinc pot to drive the zinc liquid to circulate, form sufficient shear force to prevent zinc dross particles from settling, and allow suspended zinc dross to be captured by the moving strip steel surface and carried out of the zinc pot. The strip steel temperature protection module (100), the strip steel surface cleaning module (200), and the zinc liquid dynamic purification module (300) are all electrically connected to the system controller.

2. The system for preventing slagging in zinc pots of high-alumina, zinc-alumina, and magnesium galvanizing lines according to claim 1, characterized in that, The atmosphere isolation unit includes a protective gas inlet and an exhaust outlet independently installed on the furnace shell of the rapid cooling section. The inlet is supplied with a protective gas with adjustable flow rate and pressure to form a slightly positive pressure atmosphere barrier in the rapid cooling section, thereby preventing zinc-containing ash gas from diffusing from the soaking section and slow cooling section of the annealing furnace from entering the rapid cooler.

3. The system for preventing slagging in zinc pots of high-alumina, zinc-alumina, and magnesium galvanizing lines according to claim 2, characterized in that, The online active dust removal unit includes a purge nozzle array and corresponding electrically controlled valves arranged on the upper air side of the heat exchanger plate group of the fast cooler, as well as pressure sensors located at the inlet and outlet of the fast cooler. The purge nozzle array is used to spray high-pressure nitrogen gas to remove zinc ash adhering to the heat exchanger plate of the fast cooler.

4. The system for preventing slagging in zinc pots of high-alumina, zinc-alumina, and magnesium galvanizing lines according to claim 3, characterized in that, The online active dust removal unit uses nitrogen as the purging medium in its purging nozzle array, and is triggered according to a preset time period or based on the pressure difference signal from the pressure sensors before and after the rapid cooler to perform online nitrogen purging.

5. The system for preventing slagging in zinc pots of high-alumina, zinc-alumina, and magnesium galvanizing lines according to claim 1, characterized in that, The dual active brush roller assembly is symmetrically arranged along both sides of the strip within the cleaning section, and the brush rollers on both sides rotate in opposite directions at a linear speed of 1.2 to 1.5 times the speed of the strip, so that the brush rollers and the surface of the strip always maintain a preset brushing shear force to effectively remove embedded iron powder from the surface of the strip.

6. The system for preventing slagging in zinc pots of high-alumina, zinc-alumina, and magnesium galvanizing lines according to claim 1, characterized in that, The high-power electromagnetic stirring device operates stably at rated high power in "dual coil mode", and maintains an operating power of not less than 500KW during the production process.

7. A method for preventing slagging in zinc pots of high-alumina-zinc-alumina-magnesium galvanizing lines, comprising the system for preventing slagging in zinc pots of high-alumina-zinc-alumina-magnesium galvanizing lines as described in any one of claims 1 to 6, characterized in that, Includes the following steps: S1, Iron input inhibition: S1.1 Precise control of the feed temperature: The strip feed temperature protection module is activated, and protective gas is introduced into the rapid cooling section through the atmosphere isolation unit to form a reverse airflow barrier to prevent the zinc ash-containing airflow from the upstream of the annealing furnace from entering the rapid cooler; at the same time, the zinc ash on the surface of the heat exchange plate is periodically removed through the online active ash removal unit. S1.2 Deep cleaning of strip surface: Start the strip surface cleaning module, control the double active brush roller group to rotate in the opposite direction at a set speed ratio to maintain a stable pressing amount, and continuously shear and brush the strip to remove residual iron powder, iron oxide scale and impurities on the strip surface, and reduce the total amount of iron elements entering the zinc liquid with the strip. S2, Dynamic removal of zinc dross: S2.1 Construction of longitudinal circulating flow field: The zinc liquid dynamic purification module is controlled to operate in dual-coil high-power mode to maintain rated high power output and form a longitudinal convection circulating flow field that runs through the entire zinc pot. S2.2 Continuous carry-out of suspended zinc dross: Under the action of strong electromagnetic stirring, the fine zinc dross particles generated in the zinc liquid are suspended in the zinc liquid; The suspended zinc dross that flows with the zinc liquid to the strip immersion area comes into full contact with the continuously rising strip surface and is adsorbed, leaving the zinc pot with the strip, thus achieving continuous dynamic removal of zinc dross. S3, Parameter Coordination Closed-Loop Control The system controller collects operating parameters in real time and dynamically adjusts the protective gas flow rate according to changes in strip specifications, operating speed, and coating composition using a collaborative closed-loop control algorithm to maintain a stable anti-slagging effect.

8. A method for preventing slagging in zinc pots of high-alumina, zinc-alumina, and magnesium galvanizing lines according to claim 7, characterized in that... In step S1, the online active dust removal unit is started using either differential pressure triggering mode or timed mode: When the differential pressure trigger mode is used, the differential pressure signal values ​​of the pressure sensors at the inlet and outlet of the fast cooler are monitored in real time, and when the differential pressure signal value is greater than or equal to the preset differential pressure threshold, the electronically controlled valve of the purging nozzle array is automatically opened to perform online nitrogen purging. When the timed mode is used, the electrically controlled valves of the purging nozzle array will automatically start and stop according to the preset time period.

9. A method for preventing slagging in zinc pots of high-alumina, zinc-alumina, and magnesium galvanizing lines according to claim 7, characterized in that... In step S2, the operating power of the zinc liquid dynamic purification module is maintained above the preset power value, so that the zinc liquid flow rate in the bottom area of ​​the zinc pot is not lower than the minimum flow rate threshold, so as to ensure that zinc slag particles with a particle size smaller than the preset target particle size value are always in a suspended state.

10. A method for preventing slagging in zinc pots of high-alumina, zinc-alumina, and magnesium galvanizing lines according to claim 7, characterized in that... In step S3, the calculation formula for the cooperative closed-loop control algorithm is as follows: In the formula, This refers to the volumetric flow rate of the protective gas under real-time operating conditions. The reference flow rate of protective gas corresponding to the production line's baseline operating conditions is determined by on-site thermal balance and furnace pressure calibration. These are the real-time strip running speed, strip thickness, and strip width, respectively. These are the strip speed, thickness, and width corresponding to the baseline working condition; This is the coating composition correction factor, which is determined based on the proportion of each element in the strip steel coating.

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