A converter bottom blowing dynamic control method and device based on flue gas analysis

Abstract

The present application belongs to the technical field of steel metallurgy, and relates to a converter bottom blowing dynamic control method and device based on flue gas analysis. The converter blowing process is divided into multiple process stages, the bottom blowing intensity reference value of each process stage is obtained to adjust the opening degree of the bottom blowing regulating valve of each bottom blowing branch; the in-furnace exhaust flue gas of each process stage is collected in real time, the carbon monoxide content in the in-furnace exhaust flue gas of each process stage is obtained; the deviation value of the carbon monoxide content in the in-furnace exhaust flue gas of each process stage and the corresponding carbon monoxide content reference value is calculated, and the carbon monoxide content change amount in the in-furnace exhaust flue gas of each process stage is calculated; based on the deviation value and the carbon monoxide content change amount of each process stage, the bottom blowing intensity reference value of each process stage is corrected to obtain the bottom blowing intensity target value of each process stage to adjust the opening degree of the bottom blowing regulating valve of each bottom blowing branch.

Description

Technical Field

[0001] This invention relates to the field of iron and steel metallurgy technology, and in particular to a dynamic control method and device for converter bottom blowing based on flue gas analysis. Background Technology

[0002] Bottom blowing systems in converters agitate the molten pool by injecting inert gas, thereby enhancing the chemical reaction process between slag, oxygen, and molten iron. Currently, in converter steelmaking, the intensity of bottom blowing is largely controlled based on experience or fixed patterns, lacking dynamic response to real-time operating conditions during smelting. This leads to unstable bottom blowing effects, affecting molten pool agitation efficiency, reaction uniformity, and endpoint control accuracy, ultimately impacting steel quality, smelting efficiency, and furnace lining life.

[0003] The patent with publication number CN113061684A discloses a dynamic bottom blowing method for converters based on audio slag treatment. It uses audio slag treatment to monitor the audio curve in the furnace to determine whether the molten pool has entered the "return to dryness" state. When the audio curve approaches the return to dryness area, the system automatically switches the bottom blowing flow rate from high flow rate mode to medium and low flow rate mode. Through dynamic adaptive adjustment of the bottom blowing flow rate, it improves the defects of traditional fixed parameter bottom blowing control lag, thereby alleviating problems such as smelting splashing and molten pool return to dryness caused by inaccurate control of bottom blowing adjustment timing. However, the smelting environment at the converter site is complex. During production, factors such as mechanical vibration, equipment noise, environmental noise, and fluctuations in furnace operating conditions can superimpose interference on the audio signal, causing audio curve distortion and feature shift. This leads to a decrease in the accuracy of operating condition identification and control, and insufficient system stability and reliability. At the same time, this method only focuses on the superficial characteristics of slag foaming associated with the audio signal. It can only monitor the surface level of foaming, collapse, and drying of slag in real time, and cannot penetrate the surface of the molten pool to characterize the operating conditions. It lacks the ability to perceive and quantify the evolution of internal chemical reactions such as real-time decarburization, heating, and compositional reactions in the converter. It is difficult to perform bottom blowing control based on the actual metallurgical reaction state in the furnace, and cannot meet the production requirements of high-precision, stable smelting throughout the entire process in the converter.

[0004] In summary, existing converter bottom blowing control methods suffer from low control precision and the inability to quantify the chemical reaction process within the converter, resulting in an inability to perform bottom blowing control based on the actual metallurgical state. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the problems of low control accuracy and inability to quantify the chemical reaction process in the converter in the existing converter bottom blowing control method, which makes it impossible to control the bottom blowing based on the actual metallurgical state.

[0006] To address the aforementioned technical problems, this invention provides a dynamic control method for converter bottom blowing based on flue gas analysis, comprising: The converter blowing process is divided into multiple process stages, and the bottom blowing intensity benchmark value corresponding to each process stage is obtained. The opening of the bottom blowing regulating valve of each bottom blowing branch is adjusted so that the absolute value of the difference between the bottom blowing intensity of each process stage and the corresponding bottom blowing intensity benchmark value is less than or equal to the first threshold. Real-time collection of flue gas emitted from the converter at each stage of the blowing process, and acquisition of the carbon monoxide content in the flue gas emitted from the converter at each stage of the process. Based on the in-furnace metallurgical reaction conditions at each process stage, the baseline values ​​of carbon monoxide content at each process stage are obtained. Calculate the deviation of the carbon monoxide content in the flue gas emitted from the furnace at each process stage from the corresponding carbon monoxide content benchmark value, as well as the change in the carbon monoxide content in the flue gas emitted from the furnace at each process stage. Based on the deviation values ​​and carbon monoxide content changes at each process stage, the baseline value of bottom blowing intensity for each process stage is corrected to obtain the target value of bottom blowing intensity for each process stage. This allows for the adjustment of the opening of the bottom blowing regulating valve in each bottom blowing branch, ensuring that the absolute value of the difference between the bottom blowing intensity of each process stage and the corresponding target value is less than the second threshold.

[0007] Preferably, the converter blowing process is divided into multiple process stages, including: Based on the oxygen lance being turned on until the oxygen supply reaches 12 Nm 3 / (t·min)~18Nm 3 The / (t·min) stage yields the early stage of the blowing process; Based on the period from the end of the early stage of the blowing process to the point where the oxygen supply reaches 80% to 85% of the total oxygen supply in the converter blowing process, the decarburization process stage is obtained. Based on the decarburization process stage to the stage of stopping blowing with the lance, the later stage of the blowing process is obtained. Based on the period from the end of the late-stage blowing process to the tapping stage, the settling period process stage is obtained.

[0008] Preferably, the baseline value for bottom blowing intensity in the early stage of the blowing process is 0.08 Nm. 3 / (t·min); The baseline value for bottom blowing intensity during the decarburization process is 0.03 Nm. 3 / (t·min); The baseline value for bottom blowing strength in the later stages of the blowing process is 0.08 Nm. 3 / (t·min); The baseline value for bottom blowing strength during the settling period is 0.06 Nm. 3 / (t·min).

[0009] Preferably, the flue gas emitted from the converter at each stage of the blowing process is collected in real time, and the carbon monoxide content in the flue gas emitted from the converter at each stage of the process is obtained, including: The furnace exhaust gas at each process stage is collected in real time using a collection device installed in the furnace flue. The flue gas emitted from the furnace at each process stage is filtered and its temperature is controlled to obtain the treated flue gas emitted from the furnace at each process stage. The flue gas emitted from the furnace at each stage of the process is fed into a flue gas analyzer for composition analysis to obtain the carbon monoxide content in the flue gas emitted from the furnace at each stage of the process.

[0010] Preferably, the temperature of the flue gas emitted from the furnace at each process stage after treatment is 105℃~120℃, and the content of dust particles with a particle size of 5μm or larger is less than 2%.

[0011] Preferably, the carbon monoxide content in the early stage of the blowing process is 0. The baseline value for carbon monoxide content during the decarbonization process is 40%.

[0012] Preferably, based on the deviation values ​​and carbon monoxide content changes at each process stage, the baseline value of bottom blowing intensity for each process stage is corrected to obtain the target value of bottom blowing intensity for each process stage, including: For the early stages of the blowing process, if the deviation value is less than or equal to the deviation threshold, the target value of the bottom blowing intensity is equal to the baseline value of the bottom blowing intensity; for every 10% increase in carbon monoxide content, the baseline value of the bottom blowing intensity decreases by 0.015 Nm. 3 / (t·min)~0.02Nm 3 / (t·min) yields the target value for bottom blowing intensity; for every 10% decrease in carbon monoxide content, the baseline value for bottom blowing intensity increases by 0.015 Nm. 3 / (t·min)~0.02Nm 3 / (t·min), to obtain the target value of bottom blowing intensity; For the decarbonization process stage, if the deviation value is less than or equal to the deviation threshold, the target value of the bottom blowing intensity is equal to the baseline value of the bottom blowing intensity; for every 10% increase in carbon monoxide content, the baseline value of the bottom blowing intensity decreases by 0.005 Nm. 3 / (t·min)~0.01Nm 3 / (t·min) yields the target value for bottom blowing intensity; for every 10% decrease in carbon monoxide content, the baseline value for bottom blowing intensity increases by 0.005 Nm. 3 / (t·min)~0.01Nm 3 / (t·min), to obtain the target value of bottom blowing intensity; For the later stages of the blowing process, the target value for bottom blowing intensity is increased or decreased by 0.01 Nm from the baseline value for bottom blowing intensity.3 The range of values ​​for / (t·min); For the settling period process stage, the target value of bottom blowing intensity is equal to the baseline value of bottom blowing intensity.

[0013] Preferably, the minimum bottom blowing intensity during the converter blowing process is 0.02 Nm. 3 / (t·min), the maximum bottom blowing intensity is 0.15 Nm. 3 / (t·min).

[0014] Preferably, the minimum air supply flow rate for each bottom-blowing branch is 20 Nm³. 3 / h, with a maximum gas supply flow rate of 250Nm 3 / h.

[0015] The present invention also provides a converter bottom blowing dynamic control device based on flue gas analysis, the device being used to implement the above-mentioned converter bottom blowing dynamic control method based on flue gas analysis, comprising: The data collection device is installed in the flue inside the furnace to collect the flue gas emitted from the furnace at each stage of the process in real time. The flue gas analyzer is used to analyze the composition of flue gas emitted from the furnace at each process stage to obtain the carbon monoxide content in the flue gas emitted from the furnace at each process stage. The host computer is used to divide the converter blowing process into multiple process stages and obtain the bottom blowing intensity benchmark value corresponding to each process stage; based on the in-furnace metallurgical reaction conditions of each process stage, obtain the carbon monoxide content benchmark value of each process stage; calculate the deviation value of the carbon monoxide content in the flue gas emitted from the furnace in each process stage from the corresponding carbon monoxide content benchmark value, as well as the change in carbon monoxide content in the flue gas emitted from the furnace in each process stage; based on the deviation value and the change in carbon monoxide content of each process stage, correct the bottom blowing intensity benchmark value of each process stage to obtain the bottom blowing intensity target value of each process stage.

[0016] The converter bottom blowing dynamic control method based on flue gas analysis provided in this application has the following beneficial effects: First, the converter blowing process is divided into multiple stages according to the metallurgical reaction laws. Based on the reaction characteristics of each stage, a corresponding bottom blowing intensity benchmark value is obtained, allowing for coarse adjustment of the bottom blowing intensity at each stage. This stage-by-stage customization and coarse adjustment achieve precise control of the bottom blowing intensity according to the process stages. Considering that carbon monoxide generation and real-time concentration are direct physicochemical characterization parameters of the converter's carbon-oxygen decarburization reaction, slag foaming, and the intensity of the molten pool reaction, this application collects real-time emissions from the furnace at each process stage to obtain the carbon monoxide content. This transforms the previously unquantifiable implicit chemical reaction process within the furnace into a quantifiable indicator that can be collected and calculated in real time. Then, based on the inherent metallurgical reaction conditions of each process stage, a corresponding carbon monoxide content benchmark value is set, establishing a benchmarking mechanism between the actual carbon monoxide content and the benchmark content. Using the equilibrium state of the metallurgical reaction as a reference benchmark, the control of the bottom blowing intensity is based on the actual furnace conditions. Based on the reaction state, the deviation between the actual carbon monoxide content and the reference carbon monoxide content is calculated to reflect the degree of deviation of the current operating condition from the steady-state reaction. The change in carbon monoxide content reflects the dynamic fluctuation trend of the chemical reaction in the furnace. Based on the deviation value and the fluctuation value of carbon monoxide content, the reference value of bottom blowing intensity for each process stage is dynamically corrected to generate a target value of bottom blowing intensity that is adapted to the real-time operating condition. This allows for fine-tuning of the bottom blowing intensity, realizing dynamic adaptive iteration of the bottom blowing intensity with the actual chemical reaction process in the furnace. This solves the problems of bottom blowing intensity deviating from the metallurgical reality, low control precision, and poor adaptability to operating conditions. Practical application verification shows that the method provided in this application can significantly improve the smelting effect, reducing the final phosphorus content by 33%, significantly improving the control precision of carbon content, shortening the smelting time of a single furnace by 0.5 minutes, and reducing the oxygen consumption per ton of steel by 0.9 Nm³. This fully demonstrates the practicality of bottom blowing intensity control based on flue gas analysis. Attached Figure Description

[0017] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein: Figure 1 The flowchart of the converter bottom blowing dynamic control method based on flue gas analysis provided in this application. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0019] In the early stages of converter blowing, a larger bottom blowing flow rate accelerates the oxidation of elements such as silicon, manganese, and phosphorus in the molten iron, promoting slag formation and accelerating the removal of harmful phosphorus. However, this larger flow rate also accelerates the exothermic reaction, leading to increased temperature, premature decarburization, and slag drying, which is detrimental to dephosphorization. During the decarburization period, the carbon-oxygen reaction in the converter molten pool generates a large amount of gas that stirs the pool; a larger bottom blowing intensity will accelerate slag drying, which is also detrimental to steel dephosphorization. When the carbon content in the molten steel decreases, a larger bottom blowing intensity can promote mass transfer and improve decarburization efficiency. Adjustments to the bottom blowing intensity in the later stages of blowing and during the settling period must consider both slag formation and mass transfer. Therefore, the adjustment of the bottom blowing intensity during converter blowing must be precisely adjusted according to the reaction progress within the furnace to achieve rapid slag formation and dephosphorization, and improve decarburization and composition homogenization efficiency. Based on this, this application considers that flue gas analysis technology can determine the reaction progress and trend within the furnace based on real-time changes in flue gas composition, providing guidance for precise adjustment of the bottom blowing intensity, ultimately achieving efficient, high-quality, and low-cost smelting.

[0020] Please see Figure 1 , Figure 1 The flowchart of the converter bottom blowing dynamic control method based on flue gas analysis provided in this application specifically includes S10~S50: S10: Divide the converter blowing process into multiple process stages and obtain the bottom blowing intensity benchmark value corresponding to each process stage, thereby adjusting the opening of the bottom blowing regulating valve of each bottom blowing branch so that the absolute value of the difference between the bottom blowing intensity of each process stage and the corresponding bottom blowing intensity benchmark value is less than or equal to the first threshold.

[0021] It should be noted that the division of each stage in the blowing process is based on the material and energy balance calculations of the input and output materials within the converter. For example, the division according to oxygen supply is based on the amount of oxygen required for the oxidation of elements such as silicon, manganese, phosphorus, and sulfur in the molten iron. The total oxygen supply is calculated based on the total oxygen required for all element oxidation reactions occurring during the converter smelting process. Through multiple experimental analyses, it has been found that when the oxygen supply reaches 80-85%, the carbon content in the molten steel is severely insufficient, and the decarburization rate decreases, indicating the entry into the later stage of blowing. The secondary model or expert system equipped in the converter smelting can provide this data.

[0022] Optionally, the first threshold is equal to 2% of the bottom blow intensity benchmark value.

[0023] First, based on the inherent metallurgical reaction process of the entire converter blowing process—melt pool heating, initial slag formation, intense decarburization, and homogenization of composition and temperature—this application divides the blowing process into four characteristic process stages: the early blowing stage, the decarburization stage, the late blowing stage, and the settling stage. Second, since the early blowing stage is mainly characterized by material heating, oxidation of the main heat-generating elements, and initial slag formation, strong bottom blowing stirring is required to promote molten pool mixing and slag formation; therefore, a higher bottom blowing intensity benchmark value is needed. During the decarburization stage, the carbon-oxygen reaction in the furnace is intense, and a large bottom blowing flow rate can easily cause initial splashing and subsequent drying during decarburization; therefore, a lower bottom blowing intensity benchmark value is needed. In the late blowing stage, the decarburization reaction weakens, requiring further strengthening of bottom blowing stirring to enhance carbon atom mass transfer and balance the molten pool temperature and composition; therefore, the bottom blowing intensity benchmark value needs to be increased again. Finally, during the settling stage, from lance lifting and blowing stoppage to tapping, only a small amount of bottom blowing is needed to promote deep decarburization and dephosphorization and reduce temperature drop; therefore, a moderate bottom blowing intensity benchmark value is needed.

[0024] Specifically, based on the oxygen lance being turned on until the oxygen supply reaches 12 Nm³. 3 / (t·min)~18Nm 3 The process is divided into several stages: the early stage of blowing; the decarburization stage; the late stage of blowing; and the settling stage.

[0025] Furthermore, the baseline value for bottom blowing strength in the early stages of the blowing process is 0.08 Nm. 3 / (t·min); The baseline value for bottom blowing intensity during the decarburization process stage is 0.03 Nm. 3 / (t·min); The baseline value for bottom blowing intensity in the later stages of the blowing process is 0.08 Nm. 3 / (t·min); The baseline value for bottom blowing intensity during the settling period is 0.06 Nm. 3 / (t·min).

[0026] S20: Real-time acquisition of flue gas emissions from the converter blowing process at each stage, and acquisition of carbon monoxide content in the flue gas emissions from the converter at each stage.

[0027] Furthermore, step S20 specifically includes S200~S202: S200: Real-time collection of flue gas emitted from the furnace at each process stage using a collection device installed in the furnace flue.

[0028] S201: Filter and temperature control the flue gas emitted from the furnace at each process stage to obtain the treated flue gas emitted from the furnace at each process stage.

[0029] S202: Input the flue gas emitted from the furnace at each process stage after treatment into a flue gas analyzer for flue gas composition analysis to obtain the carbon monoxide content in the flue gas emitted from the furnace at each process stage.

[0030] Preferably, the flue gas analyzer is a mass spectrometer, the sampling and analysis cycle of the flue gas is 1 second, and the bottom blowing intensity is adjusted according to the flue gas analysis results every 30 seconds.

[0031] Specifically, the temperature of the flue gas emitted from the furnace at each process stage after treatment is 105℃~120℃, and the content of dust particles with a particle size of 5μm or larger is less than 2%. This application, through constant temperature, dust removal, and precision filtration pretreatment, can avoid the corrosion of the flue gas analyzer by high-temperature dust flue gas from the converter and blockage of the detection pipeline. At the same time, it can eliminate the component detection distortion caused by dust and temperature interference, ensure the accuracy and reliability of carbon monoxide content detection data, and provide a stable data source for subsequent dynamic control of bottom blowing intensity.

[0032] S30: Based on the in-furnace metallurgical reaction conditions at each process stage, obtain the baseline value of carbon monoxide content for each process stage.

[0033] Furthermore, the baseline value for carbon monoxide content in the early stage of the blowing process is 0; the baseline value for carbon monoxide content in the decarburization stage is 40%.

[0034] Specifically, in the early stage of converter blowing, active elements such as silicon, manganese, and phosphorus are preferentially oxidized, and large-scale carbon-oxygen reaction has not yet occurred. The amount of carbon monoxide generated in the furnace is small and gradually increases. Therefore, the initial carbon monoxide content benchmark value at this stage is 0. During the decarburization period, silicon, manganese, and phosphorus elements in the molten pool are almost completely oxidized, and the molten pool temperature creates good thermodynamic conditions for carbon-oxygen reaction. The decarburization reaction in the furnace is in a stable and increasing range. Based on the characteristics of converter metallurgical reaction behavior, the initial carbon monoxide content benchmark value during the decarburization period is set at 40%.

[0035] S40: Calculate the deviation of the carbon monoxide content in the flue gas emitted from the furnace at each process stage from the corresponding carbon monoxide content benchmark value, as well as the change in carbon monoxide content in the flue gas emitted from the furnace at each process stage.

[0036] S50: Based on the deviation values ​​and carbon monoxide content changes at each process stage, the baseline value of bottom blowing intensity at each process stage is corrected to obtain the target value of bottom blowing intensity at each process stage. This allows for the adjustment of the opening of the bottom blowing regulating valve in each bottom blowing branch, ensuring that the absolute value of the difference between the bottom blowing intensity at each process stage and the corresponding target value is less than the second threshold.

[0037] Optionally, the second threshold is equal to 2% of the target value for bottom blowing intensity.

[0038] Specifically, since the real-time content and change of carbon monoxide in the converter flue gas can directly characterize the decarburization reaction rate, the strength of molten pool stirring, the foam state of molten slag, and the precursor conditions of re-drying and splashing, this application introduces the deviation of carbon monoxide content from the benchmark value and the real-time change of carbon monoxide content as dual correction factors to achieve dynamic adaptive correction of the bottom blowing intensity benchmark value according to the real-time metallurgical conditions in the furnace, thereby overcoming the defect that the traditional fixed bottom blowing mode cannot match the fluctuation of operating conditions.

[0039] Furthermore, based on the deviation values ​​and carbon monoxide content changes at each process stage, the baseline values ​​for bottom blowing intensity at each process stage are corrected to obtain the target values ​​for bottom blowing intensity at each process stage, including S500~S503: S500: For the early stage of the blowing process, if the deviation value is less than or equal to the deviation threshold, the target value of the bottom blowing intensity is equal to the baseline value of the bottom blowing intensity; for every 10% increase in carbon monoxide content, the baseline value of the bottom blowing intensity decreases by 0.015 Nm. 3 / (t·min)~0.02Nm 3 / (t·min) yields the target value for bottom blowing intensity; for every 10% decrease in carbon monoxide content, the baseline value for bottom blowing intensity increases by 0.015 Nm. 3 / (t·min)~0.02Nm 3 / (t·min) yields the target value of bottom blowing intensity.

[0040] S501: For the decarbonization process stage, if the deviation value is less than or equal to the deviation threshold, the target value of the bottom blowing intensity is equal to the baseline value of the bottom blowing intensity; for every 10% increase in carbon monoxide content, the baseline value of the bottom blowing intensity decreases by 0.005 Nm. 3 / (t·min)~0.01Nm 3 / (t·min) yields the target value for bottom blowing intensity; for every 10% decrease in carbon monoxide content, the baseline value for bottom blowing intensity increases by 0.005 Nm. 3 / (t·min)~0.01Nm 3 / (t·min) yields the target value of bottom blowing intensity.

[0041] S502: For the later stages of the blowing process, the target value of bottom blowing intensity is increased or decreased by 0.01 Nm from the baseline value of bottom blowing intensity. 3 The range of values ​​for / (t·min).

[0042] S503: For the settling period process stage, the target value of bottom blowing intensity is equal to the reference value of bottom blowing intensity.

[0043] Specifically, because the slagging reaction is sensitive in the early stage of blowing, even small fluctuations in carbon monoxide content can affect the slag formation and molten pool state. Therefore, this application sets a relatively large adjustment step size for the bottom blowing intensity. During the decarburization period, the decarburization reaction is in a steady-state self-equilibrium state, with strong resistance to disturbances, and no significant adjustment of the bottom blowing intensity is required. Therefore, a smaller adjustment step size is needed to avoid over-adjustment causing oscillations in the operating conditions. In the later stage of blowing, the reaction tends to be gentler, and only small-scale fine adjustments are needed to meet the requirements for composition and temperature balance. Therefore, the target value of the bottom blowing intensity only needs to be within ±0.01 Nm of the baseline value of the bottom blowing intensity. 3 Within a narrow range of / (t·min), there is no violent chemical reaction during the final settling period, and the operating conditions are basically constant. No further dynamic adjustment is required. Maintaining the bottom blowing intensity benchmark value is sufficient to meet the process requirements of promoting deep decarbonization and dephosphorization and reducing temperature drop.

[0044] It is worth noting that the core principle of bottom blowing intensity control in this application is that the carbon monoxide content in the flue gas is a direct quantitative indicator of the intensity of the carbon-oxygen reaction in the furnace. The higher the carbon monoxide content, the more active the carbon-oxygen reaction and the stronger the self-stirring of the molten pool. The core function of bottom blowing is to provide kinetic conditions for the metallurgical reaction. By adjusting the bottom blowing intensity, the stirring effect of the molten pool is changed, the material exchange rate between molten steel and slag is controlled, and thus the dephosphorization and decarburization process is intervened. The core requirement of the smelting process is to prioritize ensuring the full progress of the dephosphorization reaction in the early stage to avoid premature aggravation of the carbon-oxygen reaction and competition for oxygen source. In the middle and later stages, the bottom blowing intensity is adjusted according to the reaction state to prevent the molten steel from returning to phosphorus and to match the decarburization rhythm. The control trend follows that the higher the carbon monoxide content, the lower the bottom blowing intensity, but the adjustment range for different reaction stages needs to be set differently.

[0045] Furthermore, in the early stages of the blowing process, the carbon-oxygen reaction is weak, the carbon monoxide content in the flue gas is less than 10%, and carbon has not yet participated in the reaction in large quantities. Therefore, the oxygen source can adequately supply the dephosphorization reaction. At this time, a baseline bottom blowing intensity of 0.08 Nm is used. 3 / (t·min), relying on strong stirring, phosphorus in the molten iron is continuously transported to the steel slag reaction interface, thereby accelerating the dephosphorization reaction rate and allowing phosphorus to be fully oxidized and enter the slag. As blowing proceeds, carbon begins to gradually participate in the reaction, and the carbon monoxide content in the flue gas continues to rise. The carbon-oxygen reaction will consume a large amount of oxygen in the furnace, resulting in insufficient oxygen source for the dephosphorization reaction. At the same time, bottom blowing stirring will further intensify the carbon-oxygen reaction. Based on this, this application uses the increase in CO content as the adjustment basis in this stage. For every 10% increase in CO content, at a reference strength of 0.08 Nm 3Based on the set range, the bottom blowing flow rate is reduced by gradually decreasing the bottom blowing intensity and weakening the stirring of the molten pool. This reduces the migration of carbon elements to the steel-slag interface, delays the intensification of the carbon-oxygen reaction, and reserves sufficient time and oxygen source for the dephosphorization reaction, avoiding premature entry into the rapid decarburization period. During the decarburization process stage, the furnace temperature reaches the optimal conditions for the carbon-oxygen reaction, the carbon monoxide content is high, the carbon-oxygen reaction is intense and becomes the dominant reaction, and the dephosphorization reaction basically stops. It is necessary to focus on preventing the decomposition and redissolution of phosphorus compounds in the slag. At this time, the carbon-oxygen reaction produces a large number of carbon monoxide bubbles, which can form a strong stirring of the molten pool itself, without relying on the kinetic conditions of the bottom blowing intensity. Based on this, this application continues the general trend of lower bottom blowing intensity as the carbon monoxide content increases in this stage, but the reduction range is set differently from the early stage of the blowing process. It mainly relies on the stirring effect of the reaction itself to continuously weaken the bottom blowing intensity, thereby matching the decarburization rhythm while avoiding excessive stirring that causes phosphorus redissolution and ensuring the quality of the molten steel. In the later stages of the blowing process and the settling process, the carbon elements in the furnace are basically completely reacted, and the carbon-oxygen reaction gradually weakens until it stops. The carbon monoxide content in the flue gas continues to decrease and eventually approaches 0. As the carbon-oxygen reaction disappears, the self-generated stirring effect of the reaction is greatly weakened. Based on this, it is necessary to gradually restore the bottom blowing intensity in accordance with the oxidation reaction conditions of residual carbon and phosphorus in the furnace to adapt to the process requirements of the smelting end stage.

[0046] Furthermore, the minimum bottom blowing intensity during the converter blowing process is 0.02 Nm. 3 / (t·min), the maximum bottom blowing intensity is 0.15 Nm. 3 / (t·min). The minimum gas supply flow rate for each bottom-blowing branch is 20 Nm³. 3 / h, with a maximum gas supply flow rate of 250Nm 3 / h.

[0047] Specifically, the setting of the bottom blowing intensity limit and the bottom blowing gas supply flow limit of each bottom blowing branch is a reasonable limitation based on converter metallurgical safety and process constraints. Too low a bottom blowing intensity will lead to insufficient stirring of the molten pool and composition and temperature segregation, while too high a bottom blowing intensity will induce splashing and erode the furnace lining. The bottom blowing gas supply flow limit can ensure that the gas supply of each bottom blowing branch is uniform and controllable, and avoid local stirring imbalance caused by abnormal flow of a single branch.

[0048] This application embodiment also provides a converter bottom blowing dynamic control device based on flue gas analysis, used to implement the above-mentioned converter bottom blowing dynamic control method based on flue gas analysis. The device specifically includes a data acquisition device, a flue gas analyzer, and a host computer.

[0049] The data acquisition device is installed in the flue inside the furnace to collect the flue gas emitted from the furnace at each stage of the process in real time.

[0050] The flue gas analyzer is used to analyze the composition of flue gas emitted from the furnace at each process stage, and to obtain the carbon monoxide content in the flue gas emitted from the furnace at each process stage.

[0051] The host computer is used to divide the converter blowing process into multiple process stages and obtain the bottom blowing intensity benchmark value corresponding to each process stage; based on the in-furnace metallurgical reaction conditions of each process stage, obtain the carbon monoxide content benchmark value of each process stage; calculate the deviation value of the carbon monoxide content in the flue gas emitted from the furnace in each process stage from the corresponding carbon monoxide content benchmark value, as well as the change in carbon monoxide content in the flue gas emitted from the furnace in each process stage; based on the deviation value and the change in carbon monoxide content of each process stage, correct the bottom blowing intensity benchmark value of each process stage to obtain the bottom blowing intensity target value of each process stage.

[0052] The effectiveness of the above control method is verified below through specific embodiments and comparative examples: The embodiments of this application were carried out in a 180-ton top-and-bottom combined blowing converter, the steel grade was K50DNNH1, the target endpoint phosphorus content was less than or equal to 0.015%, the carbon content was 0.03%~0.06%, the hot metal conditions were: silicon content 0.45%~0.55%, manganese content 0.25%~0.35%, phosphorus content 0.12%~0.15%, sulfur content 0.02%~0.03%, and the temperature was 1380℃~1420℃.

[0053] After the converter blowing begins, the bottom blowing intensity is controlled according to the basic model: First stage (early blowing stage): from the start of oxygen lance blowing until the oxygen supply reaches 15 Nm³ / t (corresponding to an oxygen supply intensity of approximately 3.5 Nm³ / (t·min)), the baseline value of bottom blowing intensity is 0.08 Nm³ / (t·min); Second stage (decarburization period): from the end of the early blowing stage until the oxygen supply reaches 82% of the total oxygen supply (approximately 41 Nm³ / t), the baseline value of bottom blowing intensity is 0.03 Nm³ / (t·min); Third stage (late blowing stage): from the end of the decarburization period until the lance is lifted and blowing stops, the baseline value of bottom blowing intensity is 0.08 Nm³ / (t·min); Fourth stage (settling period): from the lifting of the lance and stopping blowing until the furnace is emptied and steel is tapped, the baseline value of bottom blowing intensity is 0.06 Nm³ / (t·min).

[0054] The flue gas collection device is installed in the straight pipe section of the converter vaporization cooling flue to collect, filter, and control the temperature of the flue gas in real time. The temperature of the treated flue gas is 110-115℃, and the content of dust particles with a particle size ≥5μm is <2%. The treated flue gas enters a mass spectrometer (analysis cycle 1 second) to analyze the content of components such as CO, CO2, and O2 in real time, and transmits the data to a data processor.

[0055] Based on the real-time CO content in the flue gas, the bottom blowing intensity is dynamically adjusted every 30 seconds according to the following rules: Initial blowing stage: When the CO content in the flue gas is 0%, the bottom blowing intensity remains at the baseline value of 0.08 Nm³ / (t·min); for every 10% increase in CO content, the bottom blowing intensity decreases by 0.015 Nm³ / (t·min) from the baseline value; when the CO content rises to 30%, the bottom blowing intensity decreases to 0.035 Nm³ / (t·min). Decarbonization period: Taking a CO content of 40% as the baseline point, the bottom blowing intensity remains at the baseline value of 0.03 Nm³ / (t·min); for every 10% increase or decrease in CO content, the bottom blowing intensity decreases or increases accordingly by 0.008 Nm³ / (t·min). For example, when the CO content rises to 60%, the bottom blowing intensity decreases to 0.014 Nm³ / (t·min); when the CO content drops to 30%, the bottom blowing intensity increases to 0.038 Nm³ / (t·min). Late stage of blowing: Bottom blowing intensity is set to the baseline value ±0.01 Nm³ / (t·min), and finely adjusted according to CO content fluctuations. Settling period: Maintain the stage baseline value of 0.06 Nm³ / (t·min), without adjustment based on flue gas composition.

[0056] The intensity of bottom blowing in the entire furnace was controlled within the range of 0.02 Nm³ / (t·min) to 0.15 Nm³ / (t·min). The smelting results of this furnace were as follows: the final phosphorus content of the molten steel was 0.012%, the carbon content was 0.035%, the smelting time was 33 minutes, the oxygen consumption was 45.2 Nm³ / t, the process was stable, and there was no splashing or re-drying phenomenon. The final component hit rate was high.

[0057] The comparative example in this application uses the same 180-ton converter, K50DNNH1 steel grade, and similar molten iron conditions as the example (silicon 0.48%, manganese 0.28%, phosphorus 0.13%, sulfur 0.025%, temperature 1390°C).

[0058] The smelting process control adopted traditional experience-based operation, and the endpoint determination was based on oxygen supply and flame observation. The smelting results for this furnace were: endpoint phosphorus content of 0.018%, carbon content of 0.042%, smelting time of 33.5 minutes, and oxygen consumption of 46.1 Nm³ / t. Slight re-drying occurred in the later stages of the smelting process, with significant fluctuations in the furnace mouth flame, and the endpoint composition fluctuations were more pronounced than in the previous example.

[0059] In summary, compared with the comparative examples, the embodiments using the method of this application show significant advantages in terms of endpoint phosphorus content (reduced by 33%), carbon content control accuracy, smelting time (shortened by 0.5 minutes) and oxygen consumption (reduced by 0.9 Nm³ / t), verifying the effectiveness of dynamically controlling bottom blowing intensity based on flue gas analysis.

[0060] 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.

[0061] 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.

[0062] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0063] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0064] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A dynamic control method for converter bottom blowing based on flue gas analysis, characterized in that, include: The converter blowing process is divided into multiple process stages, and the bottom blowing intensity benchmark value corresponding to each process stage is obtained. The opening of the bottom blowing regulating valve of each bottom blowing branch is adjusted so that the absolute value of the difference between the bottom blowing intensity of each process stage and the corresponding bottom blowing intensity benchmark value is less than or equal to the first threshold. Real-time collection of flue gas emitted from the converter at each stage of the blowing process, and acquisition of the carbon monoxide content in the flue gas emitted from the converter at each stage of the process. Based on the in-furnace metallurgical reaction conditions at each process stage, the baseline values ​​of carbon monoxide content at each process stage are obtained. Calculate the deviation of the carbon monoxide content in the flue gas emitted from the furnace at each process stage from the corresponding carbon monoxide content benchmark value, as well as the change in the carbon monoxide content in the flue gas emitted from the furnace at each process stage. Based on the deviation values ​​and carbon monoxide content changes at each process stage, the baseline value of bottom blowing intensity for each process stage is corrected to obtain the target value of bottom blowing intensity for each process stage. This allows for the adjustment of the opening of the bottom blowing regulating valve in each bottom blowing branch, ensuring that the absolute value of the difference between the bottom blowing intensity of each process stage and the corresponding target value is less than the second threshold.

2. The converter bottom blowing dynamic control method based on flue gas analysis according to claim 1, characterized in that, The converter blowing process is divided into multiple process stages, including: Based on the oxygen lance being turned on until the oxygen supply reaches 12 Nm³ 3 / (t·min)~18Nm 3 The / (t·min) stage yields the early stage of the blowing process; Based on the period from the end of the early stage of the blowing process to the point where the oxygen supply reaches 80% to 85% of the total oxygen supply in the converter blowing process, the decarburization process stage is obtained. Based on the decarburization process stage to the stage of stopping blowing with the lance, the later stage of the blowing process is obtained. Based on the period from the end of the late-stage blowing process to the tapping stage, the settling period process stage is obtained.

3. The converter bottom blowing dynamic control method based on flue gas analysis according to claim 2, characterized in that, The baseline value for bottom blowing strength in the early stages of the blowing process is 0.08 Nm. 3 / (t·min); The baseline value for bottom blowing intensity during the decarburization process is 0.03 Nm. 3 / (t·min); The baseline value for bottom blowing strength in the later stages of the blowing process is 0.08 Nm. 3 / (t·min); The baseline value for bottom blowing strength during the settling period is 0.06 Nm. 3 / (t·min).

4. The converter bottom blowing dynamic control method based on flue gas analysis according to claim 1, characterized in that, Real-time collection of flue gas emissions from the converter blowing process at each stage, and acquisition of carbon monoxide content in the flue gas emissions at each stage, including: The furnace exhaust gas at each process stage is collected in real time using a collection device installed in the furnace flue. The flue gas emitted from the furnace at each process stage is filtered and its temperature is controlled to obtain the treated flue gas emitted from the furnace at each process stage. The flue gas emitted from the furnace at each stage of the process is fed into a flue gas analyzer for composition analysis to obtain the carbon monoxide content in the flue gas emitted from the furnace at each stage of the process.

5. The converter bottom blowing dynamic control method based on flue gas analysis according to claim 4, characterized in that, After treatment, the temperature of the flue gas emitted from the furnace at each process stage is 105℃~120℃, and the content of dust particles with a particle size of 5μm or larger is less than 2%.

6. The converter bottom blowing dynamic control method based on flue gas analysis according to claim 1, characterized in that, The baseline value for carbon monoxide content in the early stage of the blowing process is 0; The baseline value for carbon monoxide content during the decarbonization process is 40%.

7. The converter bottom blowing dynamic control method based on flue gas analysis according to claim 1, characterized in that, Based on the deviation values ​​and carbon monoxide content changes at each process stage, the baseline values ​​for bottom blowing intensity at each process stage are corrected to obtain the target values ​​for bottom blowing intensity at each process stage, including: For the early stages of the blowing process, if the deviation value is less than or equal to the deviation threshold, the target value of the bottom blowing intensity is equal to the baseline value of the bottom blowing intensity; for every 10% increase in carbon monoxide content, the baseline value of the bottom blowing intensity decreases by 0.015 Nm. 3 / (t·min)~0.02Nm 3 / (t·min) yields the target value for bottom blowing intensity; for every 10% decrease in carbon monoxide content, the baseline value for bottom blowing intensity increases by 0.015 Nm. 3 / (t·min)~0.02Nm 3 / (t·min), to obtain the target value of bottom blowing intensity; For the decarbonization process stage, if the deviation value is less than or equal to the deviation threshold, the target value of the bottom blowing intensity is equal to the baseline value of the bottom blowing intensity; for every 10% increase in carbon monoxide content, the baseline value of the bottom blowing intensity decreases by 0.005 Nm. 3 / (t·min)~0.01Nm 3 / (t·min) yields the target value for bottom blowing intensity; for every 10% decrease in carbon monoxide content, the baseline value for bottom blowing intensity increases by 0.005 Nm. 3 / (t·min)~0.01Nm 3 / (t·min), to obtain the target value of bottom blowing intensity; For the later stages of the blowing process, the target value for bottom blowing intensity is increased or decreased by 0.01 Nm from the baseline value for bottom blowing intensity. 3 The range of values ​​for / (t·min); For the settling period process stage, the target value of bottom blowing intensity is equal to the baseline value of bottom blowing intensity.

8. The converter bottom blowing dynamic control method based on flue gas analysis according to claim 1, characterized in that, The minimum bottom blowing intensity during the converter blowing process is 0.02 Nm. 3 / (t·min), the maximum bottom blowing intensity is 0.15 Nm. 3 / (t·min).

9. The converter bottom blowing dynamic control method based on flue gas analysis according to claim 1, characterized in that, The minimum gas supply flow rate for each bottom-blowing branch is 20 Nm³. 3 / h, with a maximum gas supply flow rate of 250Nm 3 / h.

10. A converter bottom blowing dynamic control device based on flue gas analysis, characterized in that, The device is used to implement the converter bottom blowing dynamic control method based on flue gas analysis as described in any one of claims 1 to 9, comprising: The data collection device is installed in the flue inside the furnace to collect the flue gas emitted from the furnace at each stage of the process in real time. The flue gas analyzer is used to analyze the composition of flue gas emitted from the furnace at each process stage to obtain the carbon monoxide content in the flue gas emitted from the furnace at each process stage. The host computer is used to divide the converter blowing process into multiple process stages and obtain the bottom blowing intensity benchmark value corresponding to each process stage; based on the in-furnace metallurgical reaction conditions of each process stage, obtain the carbon monoxide content benchmark value of each process stage; calculate the deviation value of the carbon monoxide content in the flue gas emitted from the furnace in each process stage from the corresponding carbon monoxide content benchmark value, as well as the change in carbon monoxide content in the flue gas emitted from the furnace in each process stage; based on the deviation value and the change in carbon monoxide content of each process stage, correct the bottom blowing intensity benchmark value of each process stage to obtain the bottom blowing intensity target value of each process stage.

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