Method for preventing explosion venting of dry dedusting electrostatic precipitator in converter slag splashing period

Abstract

The invention relates to a method for preventing explosion venting of a dry dedusting electrostatic precipitator during converter slag splashing, which comprises the following steps: after converter tapping is finished or front slag is poured, lime, caustic calcined magnesia balls, a carburant, dolomite and the carburant are sequentially added for slag thickening; the lower lance is ignited to start slag splashing, and a dynamic oxygen lance control strategy is executed, specifically, the oxygen lance circularly ascends and descends with 800-1000 mm as the reference height, and the single slag splashing period is 100-360 s; dolomite is not added within 30 seconds of slag splashing, and a carburant is forbidden to be added within 60 seconds of slag splashing; the rotating speed of the fan in the whole slag splashing process is 470-530 rpm, the nitrogen flow is 54000-60000 Nm < 3 > h, and the ratio of the nitrogen flow to the rotating speed of the fan is larger than or equal to 100 Nm < 3 > (h.rpm). The explosion venting problem of the electric dust remover is effectively prevented by accurately controlling the adding amount of the carburant and parameters such as the position of the oxygen lance, the rotating speed of the fan and the nitrogen flow in the slag splashing process, and the cost is saved.

Description

Technical Field

[0001] This application relates to the field of iron and steel metallurgical process technology, and in particular to a method for preventing explosion of a dry electrostatic precipitator during converter slag splashing. Background Technology

[0002] In converter steelmaking, slag splashing is a crucial process step used to protect the furnace lining and extend furnace life. However, during slag splashing, due to the high temperature and high fluidity of the slag, the added carburizing agent and dolomite (limestone) react violently with iron oxide and iron particles in the slag, generating large amounts of carbon monoxide. This carbon monoxide accumulates within the converter fume hood and eventually reacts with oxygen under the influence of the electric field at the electrostatic precipitator location, leading to a potential explosion. This explosion not only threatens equipment safety but also causes production interruptions, increases environmental pollution, and raises production costs.

[0003] In existing patent literature, Chinese patent application CN102344987A discloses a dry dust removal process for primary flue gas in a converter; Chinese patent application CN101570808A discloses a dry dust removal system for converter gas and its explosion-proof device; Chinese patent application CN102010928A discloses a converter oxygen lance blowing control method based on a dry dust removal process; Chinese patent application CN101892343A discloses a dry dust removal system for converter gas and its usage method; and Chinese patent application CN101619375A discloses a method for preventing electrostatic precipitator explosion leakage in a top-and-bottom combined blowing converter. However, none of the above-mentioned prior art discloses how to prevent the explosion leakage problem of the electrostatic precipitator during converter slag splashing.

[0004] Therefore, the present invention aims to prevent the explosion problem of electrostatic precipitator during converter slag splashing by optimizing process parameters, thereby ensuring the safety and continuity of the production process. Summary of the Invention

[0005] This application is made in view of the above-mentioned problems, and its purpose is to provide a method for preventing explosion of dry electrostatic precipitators during converter slag splashing. The method effectively controls the generation and accumulation of carbon monoxide by optimizing the process parameters and material addition timing in converter slag splashing operation, thereby avoiding explosion accidents caused by the reaction of carbon monoxide and oxygen in the electrostatic precipitator.

[0006] Specifically, the first aspect of this application provides a method for preventing explosion venting in a dry electrostatic precipitator during converter slag splashing, comprising the following: After the converter finishes tapping or the slag is poured out, lime → lightly calcined magnesia balls → recarburizer → dolomite → recarburizer are added in sequence to thicken the slag. The oxygen lance is ignited and splashing begins, and a dynamic oxygen lance control strategy is implemented: the oxygen lance is raised and lowered in cycles at a reference height of 800-1000mm, with a single splashing cycle of 100-360s. Do not add dolomite within 30 seconds of slag splashing, and do not add carbon raiser within 60 seconds of slag splashing; Throughout the slag splashing process, the blower speed is 470-530 rpm, and the nitrogen flow rate is 54,000-60,000 Nm. 3 h, and both satisfy: nitrogen flow rate / fan speed ≥ 100 Nm 3 (h·rpm).

[0007] Furthermore, the dynamic oxygen lance control strategy specifically includes: First stage: lower the oxygen lance to 800-1000mm, splash slag for 30-120 seconds until slag is lifted; Second stage: The oxygen lance is raised to 2000-2200mm, and slag splashing occurs for 20-60 seconds; The third stage: drop by 200-500mm, all the way down to 800-1000mm; The above three phases are executed at least twice.

[0008] Furthermore, the addition of the carbon raiser must meet the following requirements: The amount of carburizing agent added within 1 minute before the end of the converter tapping process is ≤30kg; The amount added at one time during the thickening process is ≤200kg; When added, the slag viscosity should be ≥1.5 Pa·s.

[0009] Furthermore, the addition of dolomite must meet the following requirements: Dolomite addition per batch ≤ 500 kg; The slag temperature should be ≤1350℃ when added; Add the lime in a cross-feeding manner, with an interval of ≥10s.

[0010] Furthermore, the amount of lime added is 500-1000 kg, and after addition, the slag basicity (CaOSiO2) needs to be maintained within the range of 2.0-4.5.

[0011] Furthermore, the amount of lightly calcined magnesium balls added at one time is ≤500kg, the MgO content is ≥80%, and the particle size is controlled between 5-20mm.

[0012] Furthermore, it also includes: A real-time CO concentration monitoring module is installed at the inlet of the electrostatic precipitator. When the CO concentration exceeds 800 ppm, the emergency nitrogen injection system is automatically triggered, with an injection flow rate ≥ 80000 Nm. 3 h.

[0013] Furthermore, the coordinated control of the fan speed and nitrogen flow rate is achieved through a negative pressure feedback closed-loop system: The negative pressure of the converter hood is maintained at -100 to -200 Pa; If the negative pressure is greater than -100Pa, the fan speed will increase by 5%. If the negative pressure is less than -200 Pa, the nitrogen flow rate will be increased by 10%.

[0014] Furthermore, after the slag splashing is complete, the following steps are performed: Gradient lance lowering procedure: The oxygen lance is raised in segments at a rate of 200-400 mm / s, with a 10-second pause after each 500-600 mm rise; Post-purging nitrogen process: Maintain nitrogen flow rate at 28000-30000 Nm 3 h for at least 60 seconds.

[0015] Furthermore, the single slag splashing cycle is as follows: For furnaces with ≤1000 furnace cycles, the slag splashing cycle should be controlled within 100-180 seconds. For furnaces with more than 1000 furnace runs, the slag splashing cycle should be controlled between 180-360 seconds.

[0016] The present invention has the following beneficial effects: (1) This invention strictly controls the addition of dolomite within 30 seconds of slag splashing to avoid the generation of carbon dioxide from the addition of dolomite within 30 seconds of slag splashing. The generated carbon dioxide is reduced to carbon monoxide by iron particles in the slag, causing carbon monoxide to accumulate in the fume hood and ultimately leading to the explosion problem. At the same time, it controls the addition of carburizing agent within 60 seconds of slag splashing to avoid the rapid reaction of carbon in the carburizing agent with iron oxide in the slag to generate carbon monoxide, which would lead to a large accumulation of carbon monoxide in the converter fume hood. This effectively avoids the rapid generation of carbon monoxide due to the addition of materials in the early stage of slag splashing, thus reducing the explosion rate during converter slag splashing. In addition, the nitrogen flow rate is 54,000-60,000 Nm. 3 h is used to increase the concentration of inert atmosphere in the furnace and inhibit the CO formation reaction; the fan speed is 470-530 rpm; the gas residence time in the dust collector is extended; the ratio of nitrogen flow rate to fan speed is ≥100 Nm. 3 (h·rpm) is used to ensure that the amount of nitrogen input per unit time is sufficient to cover the amount of flue gas extracted by the fan, further reducing the explosion leakage rate.

[0017] (2) By precisely controlling the amount and method of adding the carbon raiser, dolomite, lime, and lightly calcined magnesia balls, as well as parameters such as the oxygen lance position, slag splashing cycle, fan speed, and nitrogen flow rate during the slag splashing process, this invention further optimizes the slag splashing operation, reducing the contact opportunities and time between iron oxide and iron particles in the slag and reactants such as carbon raiser and dolomite, thereby reducing the generation rate and total amount of carbon monoxide. These measures, working together, effectively prevent the explosion problem of the dry dust removal electrostatic precipitator during converter slag splashing, improve the safety and continuity of the production process, reduce environmental pollution and production costs, and save 67,000 yuan annually in equipment maintenance and replacement costs. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the following description and illustration are provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this application.

[0019] Obviously, the following description is merely some examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios without any inventive effort. Furthermore, it is understood that although the effort involved in such development may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, any changes to design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as insufficient disclosure of the content of this application.

[0020] This application provides a method for preventing explosion of a dry electrostatic precipitator during converter slag splashing, including the following: After the converter finishes tapping or the slag is poured out, lime → lightly calcined magnesia balls → recarburizer → dolomite → recarburizer are added in sequence to thicken the slag. The oxygen lance is ignited and splashing begins, and a dynamic oxygen lance control strategy is implemented: the oxygen lance is raised and lowered in cycles at a reference height of 800-1000mm, with a single splashing cycle of 100-360s. Do not add dolomite within 30 seconds of slag splashing, and do not add carbon raiser within 60 seconds of slag splashing; Throughout the slag splashing process, the blower speed is 470-530 rpm, and the nitrogen flow rate is 54,000-60,000 Nm. 3 h, and both satisfy: nitrogen flow rate / fan speed ≥ 100 Nm 3 (h·rpm).

[0021] Specifically, after the converter finishes tapping or after the slag has been poured out, the furnace is tilted to the zero position. The operator clicks "Start Slag Splashing" on the converter HMI Level 1 screen, and the slag splashing process begins. During the process of the oxygen lance being lowered into the converter and the slag splashing process, the operator will add lime → lightly calcined magnesia balls → recarburizing agent → dolomite → recarburizing agent in sequence to thicken the slag.

[0022] This invention strictly controls the addition of dolomite within 30 seconds of slag splashing to prevent the generation of carbon dioxide during this period. The carbon dioxide generated is reduced to carbon monoxide by iron particles in the slag, causing carbon monoxide accumulation in the fume hood and potentially leading to an explosion. Simultaneously, it controls the addition of carburizing agents within 60 seconds of slag splashing to prevent the rapid reaction of carbon in the carburizing agents with iron oxide and iron particles in the slag to generate carbon monoxide, which would also cause a large accumulation of carbon monoxide in the converter fume hood. This effectively avoids the rapid generation of carbon monoxide due to material addition at the initial stage of slag splashing, thus reducing the explosion rate during converter slag splashing. Furthermore, the nitrogen flow rate is 54,000-60,000 Nm³. 3 h is used to increase the concentration of inert atmosphere in the furnace and inhibit the CO formation reaction; the fan speed is 470-530 rpm; the gas residence time in the dust collector is extended; the ratio of nitrogen flow rate to fan speed is ≥100 Nm. 3 (h·rpm) is used to ensure that the amount of nitrogen input per unit time is sufficient to cover the amount of flue gas extracted by the fan, further reducing the explosion leakage rate.

[0023] In this embodiment, the fan speed during the slag splashing process is 470-530 rpm. Preferably, the fan speed can be any value or any range of 470 rpm, 480 rpm, 490 rpm, 500 rpm, 510 rpm, 520 rpm, and 530 rpm. During the slag splashing process, excessively high or low fan speeds are detrimental to optimizing the splashing effect. When the fan speed is too high, it accelerates the flow of gas inside the furnace, potentially increasing the contact opportunities between iron oxide in the slag and reactants such as carburizers and dolomite, thereby accelerating the formation rate of carbon monoxide. Conversely, when the fan speed is too low, the gas flow inside the furnace is sluggish, hindering the thorough mixing and reaction of the slag and potentially affecting the diffusion and discharge of carbon monoxide. Therefore, this invention, by precisely controlling the fan speed within the range of 470-530 rpm, ensures suitable gas flow inside the furnace while promoting thorough slag reaction and effective carbon monoxide diffusion, thereby further reducing the risk of explosion.

[0024] In this embodiment, the nitrogen flow rate during the slag splashing process is 54,000-60,000 Nm³. 3 / h. Preferably, the nitrogen flow rate can be 54000 Nm³. 3 / h, 55000Nm 3 / h, 56000Nm 3 / h, 57000Nm3 / h, 58000Nm 3 / h, 59000Nm 3 / h, 60000Nm 3 Any value or any range of values ​​in / h.

[0025] Nitrogen blowing into the oxygen lance at the bottom of the converter cools and thickens the slag, preventing a rapid reaction between dolomite, carburizer, and liquid slag, which could instantly generate gas and cause an explosion. Furthermore, the introduction of nitrogen plays a crucial role in the slag splashing process. On one hand, nitrogen dilutes the carbon monoxide concentration in the furnace, reducing the risk of its reaction with oxygen; on the other hand, nitrogen protects the oxygen lance from the corrosion of the high-temperature slag during slag splashing, extending its service life. This is achieved by precisely controlling the nitrogen flow rate at 54,000-60,000 Nm³. 3 Within the range of / h, it ensures the effective dilution and protection of nitrogen while avoiding excessive consumption of nitrogen, thereby further improving the safety and economy of the slag splashing process.

[0026] Specifically, it is strictly forbidden to add dolomite (limestone) within 30 seconds of slag splashing. The temperature of the slag after steelmaking in a converter reaches as high as 1000℃ and has good fluidity. If dolomite (limestone) is added within 30 seconds of slag splashing, it will rapidly decompose into carbon dioxide and calcium oxide. The generated carbon dioxide will then be reduced to carbon monoxide by iron particles in the slag, causing carbon monoxide to accumulate in the fume hood and ultimately leading to a venting explosion. Therefore, the timing of adding dolomite (limestone) must be precisely controlled, ensuring that it is added only after the slag temperature has decreased or after initial slag conditioning with lime.

[0027] Adding recarburizer within 60 seconds of slag splashing is strictly prohibited. Due to the high temperature and good fluidity of converter slag, adding recarburizer within 60 seconds of slag splashing will cause the carbon in the recarburizer to react rapidly with the iron oxide in the slag, generating carbon monoxide. This will lead to a large accumulation of carbon monoxide inside the converter fume hood. Under the influence of the electrostatic precipitator's electric field, this can easily trigger an explosion. Therefore, the timing of recarburizer addition must be carefully controlled, ensuring it is added only after the slag temperature has decreased or after initial slag conditioning with lime.

[0028] In this embodiment, the dynamic oxygen lance control strategy specifically includes: First stage: lower the oxygen lance to 800-1000mm, splash slag for 30-120 seconds until slag is lifted; Second stage: The oxygen lance is raised to 2000-2200mm, and slag splashing occurs for 20-60 seconds; The third stage: drop by 200-500mm, all the way down to 800-1000mm; The above three phases are executed at least twice.

[0029] During the slag splashing process, precise control of the oxygen lance's position and splashing time is crucial for optimizing the splashing effect. The oxygen lance initially drops to a position of 800-1000mm to ensure the slag is fully impacted and agitated, promoting a thorough reaction between the slag and the added materials. After 30-120 seconds of splashing, the oxygen lance rises to a position of 2000-2200mm for a brief splashing process, helping to adjust the slag's fluidity and prevent it from becoming too viscous, which would negatively impact the splashing effect. Subsequently, the oxygen lance drops 200-500mm down to 800-1000mm, continuing splashing, and this cycle is repeated until the end of the splashing period.

[0030] Furthermore, this invention further optimizes the slag splashing effect by precisely controlling the slag splashing cycle within the range of 100-360 seconds. The length of the slag splashing cycle directly affects the temperature, composition, and fluidity of the slag, thereby influencing the generation and accumulation of carbon monoxide. Through extensive experiments and data analysis, this invention has determined the optimal range of slag splashing cycles, ensuring both sufficient slag reaction and preventing the excessive generation and accumulation of carbon monoxide, thus effectively preventing explosion accidents.

[0031] In this embodiment, the addition of the carburizing agent must meet the following requirements: the amount of carburizing agent added within 1 minute before the end of the converter tapping process is ≤30kg; the single addition amount during the thick slag process is ≤200kg, and the slag viscosity at the time of addition is ≥1.5Pa·s. When the carburizing agent is added 1 minute before the end of tapping, the carbon in the carburizing agent will react with the iron oxide in the slag to generate iron and carbon monoxide. Since the carbon monoxide generated at this time cannot be completely diffused in time, the slag is violently stirred during the shaking process after the converter tapping process, which will accelerate the reaction with the carburizing agent and accumulate with some of the carbon monoxide generated in the later stage of tapping, causing carbon monoxide to accumulate in the converter fume hood. Under the action of the electric field of the electrostatic precipitator, carbon monoxide reacts with oxygen, thereby triggering an explosion. Therefore, strictly controlling the amount of carburizing agent added during this period can effectively prevent the accumulation of carbon monoxide during the shaking process and eliminate the hidden danger of explosion. Furthermore, the amount of carburizer added at one time is controlled to ≤200kg to reduce the reaction area and avoid the large-scale generation of carbon monoxide. The slag viscosity at the time of addition is ≥1.5 Pa·s. This is because when the slag viscosity reaches a certain level, the slag's fluidity relatively slows down, which helps control the reaction rate between the carburizer and the iron oxide in the slag, preventing the rapid and large-scale generation of carbon monoxide. At the same time, higher slag viscosity also helps maintain the stability and uniformity of the slag, making the slag splashing process more controllable and further reducing the risk of explosion.

[0032] In this embodiment, the addition of dolomite must meet the following requirements: single batch addition amount ≤ 500 kg; slag temperature ≤ 1350℃ at the time of addition; dolomite and lime are added alternately with an interval ≥ 10 s. Under high-temperature conditions, dolomite (limestone) will rapidly decompose. By alternating its addition with lime, the slag temperature can be lowered by the thickening effect of lime, effectively slowing down the decomposition reaction rate of dolomite (limestone) and the reduction process of carbon dioxide by iron. Simultaneously, controlling the single addition amount to ≤ 500 kg reduces the reaction area, thereby avoiding the large-scale generation of carbon monoxide and effectively preventing its accumulation that could lead to an explosion.

[0033] In this embodiment, the amount of lime added at one time is 500-1000 kg, and the slag basicity (CaOSiO2) must be maintained within the range of 2.0-4.5 after addition. The addition of lime aims to adjust the consistency and composition of the slag to control the generation of carbon monoxide during the slag splashing process. An appropriate amount of lime can quickly react with the iron oxide in the slag to generate stable compounds such as calcium ferrite, thereby reducing the activity of iron oxide in the slag and slowing down its reaction rate with the carbon raiser. By precisely controlling the amount of lime added within the range of 500-1000 kg, both the appropriate consistency of the slag is ensured and the amount of carbon monoxide generated during converter slag splashing is effectively reduced. When the slag basicity (CaOSiO2) is within the range of 2.0-4.5, the slag has good fluidity and stability, which is conducive to the slag splashing process and the diffusion of carbon monoxide. If the slag basicity is too high or too low, it will affect the performance of the slag and the slag splashing effect, thereby increasing the risk of explosion. Therefore, by precisely controlling the amount of lime added and the alkalinity of the slag, this invention further optimizes the slag splashing process and reduces the possibility of explosion venting.

[0034] In this embodiment, the amount of lightly calcined magnesia balls added at one time is ≤500kg, the MgO content is ≥80%, and the particle size is controlled between 5-20mm. As a slag-forming material, the addition of lightly calcined magnesia balls can further stabilize the slag composition, increase the slag melting point, and reduce slag fluidity. By rationally controlling the amount of lightly calcined magnesia balls added, a stable slag layer can be formed during slag splashing, reducing the contact area between the slag and oxygen, thereby lowering the carbon monoxide formation rate. Simultaneously, the addition of lightly calcined magnesia balls can also improve the desulfurization capacity of the slag and improve the quality of the molten steel.

[0035] The method for preventing explosion of the dry dust collector electrostatic precipitator during converter slag splashing also includes: installing a real-time CO concentration monitoring module at the inlet of the electrostatic precipitator; when the CO concentration exceeds 800 ppm, automatically triggering the nitrogen emergency injection system with an injection flow rate ≥ 80000 Nm³. 3h. This step rapidly dilutes the CO concentration at the inlet of the electrostatic precipitator, reducing the risk of its reaction with oxygen and effectively preventing explosion accidents. By monitoring the CO concentration in real time and automatically triggering the nitrogen emergency injection system, this invention achieves real-time monitoring and rapid response to potential explosion risks during slag splashing, further improving production safety and stability.

[0036] In this embodiment, the coordinated control of the fan speed and nitrogen flow rate is achieved through a negative pressure feedback closed-loop system: the negative pressure of the converter hood is maintained at -100 to -200 Pa; if the negative pressure is greater than -100 Pa, the fan speed is increased by 5%; if the negative pressure is less than -200 Pa, the nitrogen flow rate is increased by 10%. This step can dynamically adjust the fan speed and nitrogen flow rate to adapt to the changes in furnace pressure during the slag splashing process, ensuring the smooth progress of the slag splashing process. When the negative pressure of the converter hood is greater than -100 Pa, it means that the gas pressure inside the furnace is high. At this time, by increasing the fan speed, the gas discharge inside the furnace can be accelerated, the furnace pressure can be reduced, and excessive gas accumulation can be prevented from causing an explosion. When the negative pressure of the converter hood is less than -200 Pa, it indicates that the gas pressure inside the furnace is too low. At this time, by increasing the nitrogen flow rate, the gas inside the furnace can be replenished, maintaining a suitable furnace pressure environment. At the same time, nitrogen can also dilute the carbon monoxide concentration and protect the oxygen lance. Through the coordinated control of the negative pressure feedback closed-loop system, this invention achieves precise regulation of furnace pressure and gas composition during the slag splashing process, further enhancing the reliability and effectiveness of explosion prevention.

[0037] In this embodiment, after slag splashing, the following steps are performed: Gradient lance lowering procedure: The oxygen lance is raised in segments at a rate of 200-400 mm / s, pausing for 10 seconds after each 500-600 mm rise; Post-nitrogen blowing process: Nitrogen flow rate is maintained at 28000-30000 Nm. 3 The process lasts at least 60 seconds. The gradient descent procedure gradually reduces gas disturbance within the furnace during the oxygen lance's ascent, preventing rapid diffusion and accumulation of carbon monoxide. The residence time after each ascent helps ensure stable gas discharge and adequate slag cooling. The subsequent nitrogen blowing process maintains a certain nitrogen flow rate to continue diluting residual carbon monoxide and safely venting it, thus ensuring a safe furnace condition after the slag splashing process.

[0038] In this embodiment, the single slag splashing cycle is as follows: for furnace service ≤ 1000 heats, the slag splashing cycle is controlled within 100-180 seconds; for furnace service > 1000 heats, the slag splashing cycle is controlled within 180-360 seconds. By adjusting the slag splashing cycle according to different stages of the furnace service, the slag splashing effect can be further optimized and the risk of explosion can be reduced. In the early stages of the furnace service, the furnace lining is relatively intact, and the slag has relatively good fluidity and reactivity. Therefore, a shorter slag splashing cycle is sufficient to meet the requirements, and it also helps to reduce the erosion of the furnace lining by the slag and extend the service life. However, as the furnace service progresses, the furnace lining gradually wears down, and the fluidity and reactivity of the slag may change. At this time, appropriately extending the slag splashing cycle helps the slag to react fully and carbon monoxide to diffuse effectively, thereby reducing the risk of explosion.

[0039] In summary, this invention effectively prevents the explosion problem of dry dust collectors' electrostatic precipitators during converter slag splashing by strictly controlling process parameters and material addition timing in the converter slag splashing operation, as well as precisely controlling the amount of various materials added. The implementation of these measures not only improves the safety and continuity of the production process but also reduces environmental pollution and production costs, making a positive contribution to the sustainable development of the iron and steel metallurgical industry.

[0040] This invention optimizes the slag splashing operation by precisely controlling the amount and method of adding carburizing agent, dolomite, lime, and lightly calcined magnesia balls, as well as parameters such as oxygen lance position, splashing cycle, blower speed, and nitrogen flow rate during the slag splashing process. This reduces the contact opportunities and time between iron oxide in the slag and reactants such as carburizing agent and dolomite, thereby lowering the formation rate and total amount of carbon monoxide. These measures, working together, effectively prevent the explosion problem of the dry dust collector electrostatic precipitator during converter slag splashing, improve the safety and continuity of the production process, reduce environmental pollution and production costs, and save 67,000 yuan annually in equipment maintenance and replacement costs.

[0041] Example The following examples describe the disclosure of this invention in more detail. These examples are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of this disclosure. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are based on weight. Unless otherwise stated, all reagents used in the examples are available commercially or synthesized using conventional methods and are ready for use without further processing. Unless otherwise stated, all instruments used in the examples are available commercially.

[0042] Example 1 A method for preventing explosion of a dry electrostatic precipitator during converter slag splashing includes the following: The amount of recarburizing agent added within 1 minute before the end of the converter tapping is ≤30kg. After the end of the converter tapping or after the slag is poured out, lime → lightly calcined magnesia balls → recarburizing agent → dolomite → recarburizing agent are added in sequence to thicken the slag. Dolomite should not be added within 30 seconds of slag splashing, and carbon raiser should not be added within 60 seconds of slag splashing; the amount of carbon raiser added at one time should be ≤200kg; the amount of lime added should be 800kg, and the amount of lightly calcined magnesia balls added should be 600kg.

[0043] The gun is fired and splattering begins: The oxygen lance first drops to 1000mm, and the splashing occurs in 100 seconds; After slag removal, the oxygen lance rises to 2000mm, and slag splashing occurs for 40 seconds; The oxygen lance descends from 200mm to 1000mm, and this cycle repeats. The slag splashing cycle is 280s.

[0044] The fan speed during the slag splashing process is 490 rpm; the nitrogen flow rate during slag splashing is 54000 Nm. 3 / h.

[0045] Using the scheme of Example 1, the number of times the electrostatic precipitator vents during the converter slag splashing period is reduced to 0.1 times / month.

[0046] Example 2 A method for preventing explosion of a dry electrostatic precipitator during converter slag splashing includes the following: The amount of recarburizing agent added within 1 minute before the end of the converter tapping is ≤30kg. After the end of the converter tapping or after the slag is poured out, dolomite, recarburizing agent, lightly calcined magnesia balls and lime are added to thicken the slag. Dolomite should not be added within 30 seconds of slag splashing, and carbon raiser should not be added within 60 seconds of slag splashing; the amount of carbon raiser added at one time should be ≤200kg; the amount of lime added should be 600kg, and the amount of lightly calcined magnesia balls added should be 800kg.

[0047] The gun is fired and splattering begins: The oxygen lance first drops to 800mm, and slag splashes for 60 seconds; After slag removal, the oxygen lance rises to 2200mm, and slag splashing occurs for 40 seconds; The oxygen lance drops from 400mm to 1200mm, and this cycle repeats. The slag splashing cycle is 300 seconds; The fan speed during the slag splashing process is 530 rpm; the nitrogen flow rate during slag splashing is 60,000 Nm³. 3 / h.

[0048] Using the scheme of Example 2, the number of times the electrostatic precipitator vents during the converter slag splashing period is reduced to 0.2 times / month.

[0049] Comparative Example 1 In this comparative example, the amount of carburizing agent added within 1 minute before the end of the converter tapping was 60 kg, and the rest of the process was the same as in Example 1.

[0050] Using the scheme of Comparative Example 1, the number of times the electrostatic precipitator vents during the converter slag splashing period is 3.5 times / month.

[0051] The cause may be that excessive amounts of recarburizing agent were added before the end of tapping, leading to a significant increase in carbon monoxide generated during the shaking process after tapping, resulting in a reaction between the recarburizing agent and iron oxide in the slag. Because the carbon monoxide could not diffuse completely in time, and the vigorous stirring of the slag accelerated the reaction with the recarburizing agent, it also accumulated with some of the carbon monoxide generated later in the tapping process, causing a sharp rise in carbon monoxide concentration inside the converter hood. Under the electric field of the electrostatic precipitator, the carbon monoxide reacted with oxygen, triggering a potential explosion.

[0052] Comparative Example 2 In this comparative example, 400 kg of dolomite was added after 20 seconds of slag splashing, and the rest of the process was the same as in Example 1.

[0053] Using the scheme of Comparative Example 2, the number of times the electrostatic precipitator vents during the converter slag splashing period is 6.8 times / month.

[0054] The cause may be that the excessive amount of dolomite added at the initial stage of slag splashing, and the premature addition of it, caused the dolomite to rapidly decompose at high temperatures, generating carbon dioxide, which was subsequently reduced to carbon monoxide by iron particles in the slag. Because the slag temperature was high and its fluidity was good at this point, the rate and total amount of carbon monoxide formation increased significantly. Furthermore, the intense slag agitation at the initial stage of slag splashing prevented timely diffusion of carbon monoxide, leading to its accumulation in the converter hood. Under the influence of the electrostatic precipitator's electric field, carbon monoxide reacted with oxygen, subsequently triggering frequent explosions.

[0055] Comparative Example 3 In this comparative example, 300 kg of carbon raiser was added within 40 seconds of slag splashing, and the rest of the process was the same as in Example 1.

[0056] Using the scheme of Comparative Example 3, the number of times the electrostatic precipitator vents during the converter slag splashing period is 7.4 times / month.

[0057] The cause may be that the amount of carbon raiser added in the initial stage of slag splashing was too large and the timing was too early, causing the carbon in the carbon raiser to react rapidly with the iron oxide in the slag to generate a large amount of carbon monoxide. Because the slag temperature is high, its fluidity is good, and the stirring is intense in the initial stage of slag splashing, the carbon monoxide cannot diffuse in time, thus accumulating rapidly in the converter hood. When the accumulated carbon monoxide concentration reaches a certain level, under the influence of the electric field of the electrostatic precipitator, the carbon monoxide reacts with oxygen to produce high-temperature, high-pressure gas, which in turn triggers a violent explosion.

[0058] Comparative Example 4 In this comparative example, the fan speed was 510 rpm and the nitrogen flow rate was 48000 Nm throughout the slag splashing process. 3 h, nitrogen flow rate / fan speed is 94.1 Nm 3 (h·rpm), the rest of the process is the same as in Example 1.

[0059] Using the scheme of Comparative Example 4, the number of times the electrostatic precipitator vents during the converter slag splashing period is 4.7 times / month.

[0060] The reason may be that the fan speed is too high while the nitrogen flow rate is relatively insufficient, resulting in an excessively fast gas flow rate inside the furnace. Carbon monoxide is discharged before it can be fully mixed and diluted with the nitrogen, leading to localized accumulation within the electrostatic precipitator. When the accumulated carbon monoxide concentration exceeds a certain limit, it reacts with oxygen to produce high-temperature, high-pressure gas, which can then trigger an explosion. This result further verifies the effectiveness and necessity of preventing explosions by precisely controlling parameters such as fan speed and nitrogen flow rate in this invention.

[0061] Electrostatic precipitator explosions can lead to equipment damage and high maintenance costs. The solution proposed in this invention can significantly reduce the explosion failure rate, saving 67,000 yuan annually in equipment maintenance and replacement costs.

[0062] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A method for preventing explosion of a dry electrostatic precipitator during converter slag splashing, characterized in that, Includes the following: After the converter finishes tapping or the slag is poured out, lime → lightly calcined magnesia balls → recarburizer → dolomite → recarburizer are added in sequence to thicken the slag. The oxygen lance is ignited and splashing begins, and a dynamic oxygen lance control strategy is implemented: the oxygen lance is raised and lowered in cycles at a reference height of 800-1000mm, with a single splashing cycle of 100-360s. Do not add dolomite within 30 seconds of slag splashing, and do not add carbon raiser within 60 seconds of slag splashing; Throughout the slag splashing process, the blower speed is 470-530 rpm, and the nitrogen flow rate is 54,000-60,000 Nm. 3 h, and both satisfy: nitrogen flow rate / fan speed ≥ 100 Nm 3 (h·rpm).

2. The method for preventing explosion of a dry electrostatic precipitator during converter slag splashing according to claim 1, characterized in that, The dynamic oxygen lance control strategy specifically includes: First stage: lower the oxygen lance to 800-1000mm, splash slag for 30-120 seconds until slag is lifted; Second stage: The oxygen lance is raised to 2000-2200mm, and slag splashing occurs for 20-60 seconds; The third stage: drop by 200-500mm, all the way down to 800-1000mm; The above three phases are executed at least twice.

3. The method for preventing explosion of a dry electrostatic precipitator during converter slag splashing according to claim 1, characterized in that, The addition of the carbon raiser must meet the following requirements: The amount of carburizing agent added within 1 minute before the end of the converter tapping process is ≤30kg; The amount added at one time during the thick slag process is ≤200kg, and the slag viscosity at the time of addition is ≥1.5Pa·s.

4. The method for preventing explosion of a dry electrostatic precipitator during converter slag splashing according to claim 1, characterized in that, The addition of dolomite must meet the following requirements: Dolomite addition per batch ≤ 500 kg; The slag temperature should be ≤1350℃ when added; Add the lime in a cross-feeding manner, with an interval of ≥10s.

5. The method for preventing explosion of a dry electrostatic precipitator during converter slag splashing according to claim 1, characterized in that, The amount of lime added is 500-1000 kg, and the slag alkalinity must be maintained within the range of 2.0-4.5 after addition.

6. The method for preventing explosion of a dry electrostatic precipitator during converter slag splashing according to claim 1, characterized in that, The amount of lightly calcined magnesium balls added at one time is ≤500kg, the MgO content is ≥80%, and the particle size is controlled between 5-20mm.

7. The method for preventing explosion of a dry electrostatic precipitator during converter slag splashing according to claim 1, characterized in that, Also includes: A real-time CO concentration monitoring module is installed at the inlet of the electrostatic precipitator. When the CO concentration exceeds 800 ppm, the emergency nitrogen injection system is automatically triggered, with an injection flow rate ≥ 80000 Nm. 3 / h.

8. The method for preventing explosion of a dry electrostatic precipitator during converter slag splashing according to claim 7, characterized in that, The coordinated control of the fan speed and nitrogen flow rate is achieved through a negative pressure feedback closed-loop system. The negative pressure of the converter hood is maintained at -100 to -200 Pa; If the negative pressure is greater than -100Pa, the fan speed will increase by 5%. If the negative pressure is less than -200 Pa, the nitrogen flow rate will be increased by 10%.

9. The method for preventing explosion of a dry electrostatic precipitator during converter slag splashing according to claim 1, characterized in that, Perform the following after the slag splashing is complete: Gradient lance lowering procedure: The oxygen lance is raised in segments at a rate of 200-400 mm / s, with a 10-second pause after each 500-600 mm rise; Post-purging nitrogen process: Maintain nitrogen flow rate at 28000-30000 Nm 3 h for at least 60 seconds.

10. The method for preventing explosion of a dry electrostatic precipitator during converter slag splashing according to claim 1, characterized in that, The single slag splashing cycle is: For furnaces with ≤1000 furnace cycles, the slag splashing cycle should be controlled within 100-180 seconds. For furnaces with more than 1000 furnace runs, the slag splashing cycle should be controlled between 180-360 seconds.