Automatic combustion control method and system for slag pulverizer hot blast stove

Abstract

The invention discloses an automatic combustion control method and system for a slag pulverizer hot blast stove. The method comprises the following steps: acquiring operation parameters of a hot-blast stove and a slag pulverizer; selecting one of a furnace temperature control mode and a flow control mode for execution according to the production stage; the total target gas flow is calculated in the selected mode, wherein the flow control mode is subjected to prospective adjustment according to a linkage rule base of mill operation parameters; the air-fuel ratio is corrected based on double feedback of coal gas components and flue gas residual oxygen; and finally, distributing the target flow to a plurality of burners and executing combustion. Through dual-mode switching and intelligent linkage with the mill, conversion from reaction type control to predictive type control is achieved, thermal lag is effectively overcome, combustion efficiency is ensured through dynamic air-fuel ratio correction, and the energy utilization rate, operation stability and automation level of the system are remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of slag grinding production, and particularly relates to a slag grinder hot blast stove automatic combustion control method and system. BACKGROUND

[0002] In the slag grinding production process, the hot blast stove is a key equipment for providing hot air for the grinder, and accurate control of the combustion state of the hot blast stove is crucial for grinding efficiency, product quality, and energy utilization efficiency and safety of the entire production system. However, the traditional hot blast stove control method has many limitations: 1. Reaction control and thermal hysteresis: the perception of various parameters related to the operation of the hot blast stove and the grinder is not comprehensive and accurate enough, and it is difficult to perform fine dynamic regulation according to real-time working conditions. The traditional control method usually takes the furnace temperature or outlet hot air temperature of the hot blast stove as the main control target. However, temperature is a typical lagging parameter. When the system detects that the temperature deviates from the set value, it usually means that the production conditions (such as the moisture, particle size or feed amount of the slag entering the grinder) have changed significantly. At this time, adjustment is made, and due to the existence of thermal inertia, the system responds slowly, making it difficult to quickly stabilize the temperature, resulting in large fluctuations in hot air temperature, affecting the grinding effect and product quality. 2. Static air-fuel ratio and energy waste: The hot blast stove usually uses blast furnace gas, a byproduct of the steel plant, as fuel. The calorific value of blast furnace gas frequently fluctuates due to the influence of blast furnace smelting conditions. The traditional control system uses a fixed air-fuel ratio for combustion control, which cannot dynamically adjust the supply of combustion air according to the real-time changes in gas composition. This results in insufficient combustion air supply when the gas calorific value is high, leading to incomplete combustion and the production of harmful gases such as CO, and waste of energy. When the gas calorific value is low, the combustion air supply is excessive, taking away a lot of heat and reducing the thermal efficiency. 3. Poor system coordination: In the traditional control logic, the hot blast stove and the slag grinder are controlled as two independent units. The combustion load adjustment of the hot blast stove is mainly based on its own temperature, and cannot respond to changes in the load on the grinder side. For example, when the load (main motor current) of the grinder increases due to an increase in material moisture, it indicates that more heat is needed, but the temperature on the hot blast stove side has not decreased, resulting in a delay in heat supply. This lack of forward-looking coordinated control is one of the root causes of unstable system operation and energy waste. 4. Lack of fault tolerance: The hot blast stove is usually equipped with multiple burners to ensure uniform combustion. When a burner fails due to blockage or other reasons, the traditional system lacks an effective automatic load redistribution mechanism, often requiring manual intervention or even shutdown for processing, which seriously affects the continuity of production.

[0003] Therefore, it is urgent to develop an intelligent automatic combustion control technology which can overcome the above-mentioned defects, realize efficient cooperation between the hot blast furnace and the slag grinding mill, and have self-adaptive ability and fine adjustment ability. SUMMARY

[0004] The present application aims at solving the problems of inaccurate sensing and control, rigid parameter setting, imperfect control logic and poor cooperation with the mill in the traditional control method of the slag grinding mill hot blast furnace in the background art, and provides a slag grinding mill hot blast furnace automatic combustion control method and system, which can intelligently switch control strategies, dynamically correct combustion parameters, and realize fault-tolerant control of multiple burners according to different production stages and real-time mill working conditions, thereby significantly improving combustion efficiency, energy utilization rate and operation stability of the entire production system.

[0005] To achieve the above-mentioned purpose, the present application is implemented by the following technical solutions: The present application provides a slag grinding mill hot blast furnace automatic combustion control method, comprising: A slag grinding mill hot blast furnace automatic combustion control method applied to a system comprising a hot blast furnace and a slag grinding mill linked with the hot blast furnace, wherein the hot blast furnace has multiple burners, and the method comprises the following steps: a. Data acquisition: acquiring the operating parameters of the hot blast furnace and the operating parameters of the slag grinding mill, wherein the operating parameters of the hot blast furnace at least include furnace temperature, furnace pressure, blast furnace gas composition, gas flow of each burner, combustion-supporting air flow of each burner and residual oxygen content of flue gas, and the operating parameters of the slag grinding mill at least include main motor current of the mill, opening degree of the cold air valve and opening degree of the circulating air valve; b. Selection of control mode: selecting one of at least two preset control modes according to the production stage of the hot blast furnace, wherein the control modes include a furnace temperature control mode for the stage of starting the furnace or maintaining the temperature, and a flow control mode for the stage of linkage production with the slag grinding mill; c. Calculation of target flow: if the current selected control mode is the furnace temperature control mode, the total target gas flow is calculated based on the temperature deviation ΔT between the preset required temperature and the acquired furnace temperature, and the temperature rise change ΔP of the furnace temperature within the sampling period; If the current selected control mode is the flow control mode, the total target gas flow is adjusted and determined according to the preset linkage rule library according to the combined state of the main motor current of the mill, the opening degree of the circulating air valve and the opening degree of the cold air valve; d. Air-fuel ratio correction: calculating the ideal air-fuel ratio based on the real-time acquired blast furnace gas composition, and calculating the residual oxygen correction factor according to the residual oxygen value of the exhaust gas, and multiplying the ideal air-fuel ratio by the residual oxygen correction factor to obtain the corrected air-fuel ratio; e. Combustion execution: the total gas target flow is evenly distributed to multiple burners to obtain the gas target flow of each burner, and the corresponding combustion air target flow of each burner is calculated according to the corrected air-fuel ratio, and then the opening degrees of the gas flow regulating valve and the combustion air flow regulating valve of each burner are controlled to adjust the supply amounts of gas and combustion air.

[0006] Further, in the step c, the step of calculating the total gas target flow in the furnace temperature control mode specifically comprises: When the demand temperature setting does not change, the total gas target flow is calculated according to the following formula: Total gas target flow = original total gas target flow + (ΔT + ΔP) × K1, Wherein, K1 is a preset gas flow regulating coefficient; When the demand temperature setting changes, the total gas target flow is calculated according to the following formula: ΔS = new demand temperature setting value - original demand temperature setting value, Total gas target flow = original total gas target flow + ΔS × K2, Wherein, K2 is a preset temperature change response coefficient; And K1 > K2.

[0007] Further, in the step c, in the flow control mode, the linkage rule base comprises at least one of the following rules: When the circulating air valve opening degree is greater than or equal to the first threshold value and the cold air valve opening degree is less than or equal to the second threshold value, the total gas target flow is adjusted according to the change amount of the cold air valve opening degree or the change trend of the main mill motor current; When the circulating air valve opening degree is less than or equal to the third threshold value and the cold air valve opening degree is less than or equal to the fourth threshold value, the total gas target flow is adjusted according to the change amount or absolute value of the main mill motor current; When the main mill motor instantaneous current exceeds a preset overload protection threshold value, or the circulating air valve opening degree is lower than a preset fourth threshold value, resulting in a serious shortage of ventilation, the total gas target flow is greatly increased.

[0008] Further, in the step d, the specific steps of air-fuel ratio correction comprise: The volume content of combustible components (including CO, H2, CH4) in the blast furnace gas is detected in real time by a calorific value analyzer, and the ideal air-fuel ratio is calculated according to the chemical combustion equation; The residual oxygen value in the flue gas after combustion is detected by a residual oxygen analyzer, and when the residual oxygen value deviates from a preset optimal range, the residual oxygen correction factor is calculated according to the formula residual oxygen correction factor = 1 + (actual residual oxygen value - optimal residual oxygen intermediate value) × 0.1. The ideal air-fuel ratio is multiplied by the residual oxygen correction factor to obtain the corrected air-fuel ratio for combustion control.

[0009] Further, the step e of distributing the total gas target flow comprises the following steps: presetting selectable control modes for each burner, the selectable control modes including an automatic control mode, a follow-up control mode and a manual control mode; calculating and distributing the gas target flow of each burner in the automatic control mode according to the formula: burner gas target flow = (total gas target flow - F) / N; wherein N is the number of burners in the automatic control mode, and F is the total gas flow of burners in the follow-up or manual control mode.

[0010] Further, the control method of the gas flow regulating valve and the combustion air flow regulating valve of each burner in different control modes in the step e is as follows: if the burner is in the automatic control mode, the opening degree of the gas flow regulating valve corresponding to the burner is automatically adjusted based on the gas target flow and the burner gas measurement flow, and the opening degree of the combustion air flow regulating valve corresponding to the burner is automatically adjusted based on the corrected air-fuel ratio relationship between the burner combustion air measurement flow and the burner gas measurement flow; if the burner is in the follow-up control mode, the opening degree of the gas flow regulating valve corresponding to the burner is manually set based on the gas target flow, and the opening degree of the combustion air flow regulating valve corresponding to the burner is automatically adjusted based on the corrected air-fuel ratio relationship between the burner combustion air measurement flow and the burner gas measurement flow; if the burner is in the manual control mode, the opening degree of the gas flow regulating valve corresponding to the burner is manually adjusted based on the gas measurement flow, and the opening degree of the combustion air flow regulating valve corresponding to the burner is manually set based on the corrected air-fuel ratio relationship between the gas measurement flow and the combustion air flow.

[0011] Further, the adjustment method of the gas flow regulating valve corresponding to the burner in the automatic control mode in the step e is as follows: if the burner gas target flow > burner gas measurement flow x a1, the opening degree of the gas flow regulating valve is controlled to increase; if the burner gas target flow < burner gas measurement flow x a2, the opening degree of the gas flow regulating valve is controlled to decrease; The adjustment method of the combustion air flow regulating valve corresponding to the burner in the automatic control mode and the follow-up control mode is as follows: if the burner combustion air measurement flow > burner gas measurement flow x corrected air-fuel ratio x b1, the opening degree of the combustion air flow regulating valve is controlled to decrease; If each burner combustion air measured flow < each burner gas measured flow × corrected air-fuel ratio × β2, control the combustion air flow regulating valve opening to increase; Wherein, α1, α2, are respectively preset first burner gas flow adjustment coefficient and second burner gas flow adjustment coefficient, β1, β2 are respectively preset first burner combustion air flow adjustment coefficient and second burner combustion air flow adjustment coefficient.

[0012] Further, it also includes a gas pressure stabilizing step before the blast furnace gas enters the burner: A gas pressure sensor and a pressure stabilizing valve are arranged on the gas main pipeline; The gas pressure is monitored in real time by the gas pressure sensor, and a PID closed-loop control algorithm is used to adjust the opening of the pressure stabilizing valve, so that the gas pressure after the valve is stabilized within the preset target pressure range.

[0013] A slag mill hot blast stove automatic combustion control system, applied to a system including a hot blast stove and a slag mill linked with the hot blast stove, the hot blast stove having a plurality of burners, characterized in that it comprises: A data acquisition unit configured to acquire the operating parameters of the hot blast stove and the slag mill in real time, the hot blast stove operating parameters including furnace temperature, furnace pressure, blast furnace gas composition, each burner gas flow, each burner combustion air flow, and residual oxygen content of flue gas, and the slag mill operating parameters including main motor current, cold air valve opening, and circulating air valve opening; An execution unit including at least a plurality of gas flow regulating valves for regulating the gas flow of each burner gas branch pipeline and a plurality of combustion air flow regulating valves for regulating the combustion air flow of each burner combustion air branch pipeline; A controller in communication connection with the data acquisition unit and the actuator unit, the controller being configured to execute the method of any one of the above slag mill hot blast stove automatic combustion control methods.

[0014] Further, the controller comprises: A control mode selection module for selecting between furnace temperature control mode and flow control mode according to the production stage of the hot blast stove; A target flow calculation module for calculating the total gas target flow according to the selected control mode; An air-fuel ratio correction module for calculating the corrected air-fuel ratio based on the blast furnace gas composition and the residual oxygen value of the exhaust gas; A burner control module for distributing the total gas target flow to a plurality of burners and controlling the combustion process according to the corrected air-fuel ratio.

[0015] Further, the target flow calculation module comprises: a furnace temperature control submodule configured to calculate the total target gas flow based on a temperature deviation and a temperature rise change in the furnace temperature control mode; a flow control submodule internally containing a linkage rule base and configured to adjust and determine the total target gas flow based on a combination of the main mill motor current, the circulating air valve opening degree and the cold air valve opening degree according to the linkage rule base in the flow control mode.

[0016] Further, the burner control module is further configured to: allow each burner to be independently set to an automatic, follow-up or manual control mode; when it is detected that a certain burner is in a non-automatic control mode, the remaining gas flow after the total target gas flow is subtracted by the gas flow corresponding to the burners in the manual or follow-up mode is dynamically and evenly distributed to the burners in the automatic control mode.

[0017] Further, the controller is further configured to: a safety interlock logic is preset, the safety interlock logic includes: when at least one of flameout, low gas pressure, low combustion air pressure or abnormal furnace temperature is detected, an alarm is given and a gas quick cut valve on a gas main is automatically closed.

[0018] Compared with the prior art, the technical scheme provided by the present application has the following beneficial effects: 1. The present application is based on real-time analysis of blast furnace gas composition and double feedback of residual oxygen content in flue gas after combustion, dynamically corrects the air-fuel ratio, ensures that the fuel can achieve nearly complete chemical combustion under various working conditions, improves the thermal efficiency from the source, and in the flow control mode, the fuel supply of the hot blast stove is directly linked to the actual load of the mill (represented by parameters such as the main mill motor current, the circulating air valve and the cold air valve opening degree), realizing the change from "temperature control" to "on-demand energy supply", effectively avoiding energy waste caused by mismatch between supply and demand; 2. The dual-mode control strategy (furnace temperature control mode and flow control mode) of the present application ensures stable control of the hot blast stove in all stages such as point furnace, heat preservation and linkage production, especially in the linkage production stage, the flow control mode can effectively suppress the large temperature change in the mill caused by external disturbances such as fluctuation of the moisture of the material entering the mill, providing a stable process environment for slag grinding, thereby significantly improving the quality uniformity and yield of slag powder products; 3、The present application integrates the complex combustion control logic and the cooperative strategy with the mill into an automatic program, greatly reduces the frequency and difficulty of manual intervention, perfects the independent control and fault-tolerant logic of the burner, so that the system can automatically redistribute the combustion load when a single burner is abnormal, guarantees the production continuity, and the operator can monitor two mills at the same time from the original one-man operation of one mill, the risk of human error is reduced by more than 90%, which not only reduces the labor intensity of the operator, but also avoids the equipment damage or safety accidents caused by human operation errors, significantly improves the efficiency and safety of production management; 4、The present application designs a complete coal gas pressure stabilizing, combustion-supporting air pressure stabilizing cooperative control and multiple safety interlocking protection mechanism, maintains the stability of the coal gas and combustion-supporting air pressure through PID closed-loop control, provides a basis for safe combustion, at the same time, the integrated multiple safety interlocking logic such as flameout, overpressure and overtemperature can quickly respond when any dangerous working condition is detected, automatically cut off the fuel supply, effectively prevent the occurrence of malignant accidents such as combustion out of control, backfire and explosion, and provide a solid guarantee for equipment and personnel safety. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0020] Figure 1 The control logic diagram of the present application slag powder mill hot blast stove automatic combustion control method; Figure 2 The structure diagram of the present application slag powder mill hot blast stove automatic combustion control system.

[0021] The numbers in the figure represent respectively: 1-gas main pipeline, 2-gas calorific value analyzer, 3-pressure stabilizing valve, 4-gas pressure sensor, 5-gas branch pipeline, 6-burner gas flow meter, 7-burner gas flow regulating valve, 8-burner, 9-combustion air blower, 10-combustion air main pipeline, 11-combustion air pressure sensor, 12-burner combustion air branch pipeline, 13-burner combustion air flow meter, 14-burner combustion air flow regulating valve, 15-hot blast stove, 16-furnace temperature sensor, 17-furnace pressure sensor, 18-residual oxygen analyzer, 19-cold blast valve, 20-circulating air valve, 21-slag grinding mill, 22-grinding main motor, 23-dust collector, 24-main exhaust fan, 25-waste gas discharge valve, 26-mill inlet belt, 27-waste gas chimney, 28-controller, 29-gas quick switching valve, 30-flame detector, 31-nitrogen main pipeline, 32-nitrogen pressure sensor. DETAILED DESCRIPTION

[0022] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0023] The present application will be further described below with reference to the embodiments.

[0024] Please refer to Figure 1 The present application provides a slag grinding mill hot blast stove automatic combustion control method, comprising the following steps: a. Data acquisition: collecting the operating parameters of the hot blast stove and the operating parameters of the slag grinding mill linked with the hot blast stove, wherein the operating parameters of the hot blast stove at least include the furnace temperature, the furnace pressure, the blast furnace gas composition, the gas flow of each burner, the combustion air flow of each burner and the residual oxygen content of the flue gas, and the operating parameters of the slag grinding mill at least include the grinding main motor current, the cold blast valve opening degree and the circulating air valve opening degree; Before this step, the basic parameters need to be set according to the production requirements and the operating state of each burner, the burner is initialized, the initial conditions and the reference values are determined; In this embodiment, the lower limit value 4000 and the upper limit value 22000 of the total gas flow (i.e. the sum of the gas flow of each burner) are specified, so as to ensure that the gas supply is always in a safe and effective range, which can meet the combustion requirements of the hot blast stove and prevent various problems caused by insufficient or excessive gas supply.

[0025] b. Selecting control mode: according to the production stage of the hot blast stove, one of at least two preset control modes is selected for execution, including the stove temperature control mode for the stove warming-up or holding stage, and the flow control mode for the slag mill interlinked production stage; According to the specific requirements of the slag mill for hot blast temperature in different production stages (including the stove warming-up stage and the slag mill interlinked production stage): The stove temperature control mode is adopted in the stove warming-up stage, and when the hot blast stove temperature ≥ 800℃, the warming-up is completed, the temperature is controlled at 1050℃, and the mill feeding production condition is met, at which time the flow control mode needs to be switched.

[0026] c. Calculate the target flow: If the current selection is the stove temperature control mode, the total target flow of the coal gas is calculated based on the temperature deviation ΔT between the preset required temperature and the collected stove temperature, and the temperature rise change ΔP of the stove temperature in the sampling period; Specifically, the total target flow calculation method of the coal gas in the stove temperature control mode is as follows: The actual stove temperature data is collected in real time by the thermocouple arranged in the stove, and the required temperature is set in advance, the temperature deviation ΔT = required setting temperature-actual temperature is calculated, and the actual temperature of the current sampling is subtracted from the last sampling stove temperature, the sampling period temperature rise change ΔP = last sampling stove temperature-actual temperature is calculated; When the required temperature setting does not change, the total target flow of the coal gas is calculated according to the following formula: Total target flow of coal gas = original total target flow of coal gas + (ΔT+ΔP) ×K1; Wherein, K1 is a preset coal gas flow adjustment coefficient, and the formula considers the current deviation and change trend, so that the adjustment is more stable and accurate; When the required temperature setting changes, the total target flow of the coal gas is calculated according to the following formula: ΔS = new temperature required setting value - original temperature required setting value, Total target flow of coal gas = original total target flow of coal gas + ΔS ×K2, Wherein, K2 is a preset temperature change response coefficient, and when the operator manually changes the required temperature setting value, the system adopts a fast response strategy; In this embodiment, K1 = 300, K2 = 100; By setting the deviation between the required temperature and the actual temperature and the temperature rise change, the automatic adjustment of the total target flow of the automatically combusted coal gas is realized.

[0027] In the embodiment, in order to realize more fine control, the temperature deviation ΔT and the temperature rise change ΔP are divided into multiple hierarchical intervals, each interval corresponds to a preset control parameter, and the calculation of the total target flow of the fuel gas is further based on the control parameter: Temperature deviation ΔT: by the formula temperature deviation ΔT = demand setting temperature - actual temperature, sample comparison every five minutes, different value ranges correspond to sampling interval temperature deviation control coefficient cha_mh, as follows: ① ΔT > 15℃, cha_mh = 4; ② 10℃ < ΔT ≤ 15℃, cha_mh = 3; ③ 8℃ < ΔT ≤ 10℃, cha_mh = 2; ④ 5℃ < ΔT ≤ 8℃, cha_mh = 1; ⑤ -5℃ < ΔT ≤ 5℃, cha_mh = 0; ⑥ -8℃ < ΔT ≤ -5℃, cha_mh = -1; ⑦ -10℃ < ΔT ≤ -8℃, cha_mh = -2; ⑧ -15℃ < ΔT ≤ -10℃, cha_mh = -3; ⑨ ΔT ≤ -15℃, cha_mh = -4.

[0028] Temperature rise change ΔP: according to the formula, the temperature rise change ΔP = last sampling furnace temperature - actual temperature is calculated, and sample comparison is performed every five minutes, different value ranges correspond to sampling interval temperature rise change control coefficient cha_bh, as follows: ① ΔP > 9℃, cha_bh = 3; ② 6℃ < ΔP ≤ 9℃, cha_bh = 2; ③ 3℃ < ΔP ≤ 6℃, cha_bh = 1; ④ -3℃ < ΔP ≤ 3℃, cha_bh = 0; ⑤ -6℃ < ΔP ≤ -3℃, cha_bh = -1; ⑥ -9℃ < ΔP ≤ -6℃, cha_bh = -2; ⑦ ΔP ≤ -9℃, cha_bh = -3.

[0029] If the current selection is the flow control mode, according to the combination state of the mill main motor current, the circulating air valve opening degree and the cold air valve opening degree, the total target flow of the coal gas is adjusted and determined according to the preset linkage rule library, and the core idea of this mode is: instead of taking the furnace temperature as the direct control target (because of its large hysteresis), the change of the heat load is predicted by monitoring the key parameters of the mill system, and the coal gas flow is adjusted in advance, so as to realize the close cooperation of the hot blast furnace and the mill and "on-demand energy supply". Specifically, in the flow control mode, the coal gas total target flow calculation method is as follows: The linkage rule base includes the following rules: When the circulating air valve opening is greater than or equal to a first threshold value and the cold air valve opening is less than or equal to a second threshold value, the coal gas total target flow is adjusted according to the change amount of the cold air valve opening or the change trend of the mill main motor current; When the circulating air valve opening is less than or equal to a third threshold value and the cold air valve opening is less than or equal to a fourth threshold value, the coal gas total target flow is adjusted according to the change amount or absolute value of the mill main motor current; When the mill main motor instantaneous current exceeds a preset overload protection threshold value, the coal gas total target flow is greatly increased.

[0030] More specifically, in the embodiment, the linkage rule base is specifically as follows: 1) circulating air valve opening ≥ 92%, 0% ≤ cold air valve opening ≤ 30% When 5 ≤ cold air valve opening change value < 10, the coal gas total target flow is reduced by 300 (every 5 minutes of detection); When 10 ≤ cold air valve opening change value < 15, the coal gas total target flow is reduced by 500 (every 5 minutes of detection); When 15 ≤ cold air valve opening change value, the coal gas total target flow is reduced by 1000 (every 5 minutes of detection); When the cold air valve opening change value ≤ -20 (i.e. the cold air valve is closed by 20%), the coal gas total target flow is increased by 500 (every 5 minutes of detection); When the mill main motor average current > (target current + 1A) and the 20s continuous rising trend, the coal gas flow is increased by 500, if the current has no downward trend after 30s, the coal gas total target flow continues to increase by 500, if there is a downward trend, no coal gas is added.

[0031] 2) circulating air valve opening ≥ 92%, cold air valve opening > 30%, mill main motor average current < (target value - 3A) When it appears for the first time, the coal gas total target flow is directly reduced by 1000; When the coal gas total target flow is reduced by 1000: if the current still continuously decreases for more than 10s after 30s, the coal gas total target flow continues to be reduced by 1000; 3) circulating air valve opening ≤ 90%, cold air valve opening ≤ 5%, (target current - 3) < mill main motor average current < target current (every 1 minute of detection) When 1A < mill main motor average current change value ≤ 2A, the coal gas total target flow is increased by 300 (every 1 minute of detection); When the average current of the main motor changes by >2A, the total gas target flow is increased by 500 (every 1 minute is detected).

[0032] 4) The circulating air valve opening is ≤90%, the cold air valve opening is ≤5%, and the target current < the average current of the main motor < (target current + 3A) (every 30S is detected) If the average current of the main motor increases by >1A and <3A within 30s, the total gas target flow is increased by 500.

[0033] 5) The circulating air valve opening is ≤90%, the cold air valve opening is ≤5%, and the average current of the main motor is ≥(target current + 3A); If it occurs for the first time, the total gas target flow is directly increased by 1000; After 30S, if the average current of the main motor continues to rise by more than 10A, the total gas target flow is increased by 1000, and if the current decreases, the increase in gas is stopped; 6) The instantaneous current of the main motor >312A for 5 minutes, and the total gas target flow is increased by 1000 (main motor instantaneous flow protection); The instantaneous current of the main motor >320A for 1 minute, and the total gas target flow is increased by 1000; The instantaneous current of the main motor >330A for five seconds, and the total gas target flow is increased by 1000; That is, in the flow control mode, the focus is on the circulating air valve opening, the cold air valve opening, the main motor current, and other parameter combinations to develop a total gas flow adjustment strategy to achieve efficient cooperation between the hot blast furnace and the slag powder grinding mill. According to the change of the mill working condition, that is, the change of the water content of the water slag entering the mill causes the change of the mill current, combined with the combination of the circulating air valve, the cold air valve, and the main motor current of the mill, the gas flow is adjusted to realize the efficient linkage of the hot blast furnace and the slag powder grinding mill.

[0034] d. Air-fuel ratio correction: calculate the ideal air-fuel ratio based on the real-time collected gas composition of the blast furnace, and calculate the residual oxygen correction factor according to the residual oxygen value of the exhaust gas, multiply the ideal air-fuel ratio by the residual oxygen correction factor to obtain the corrected air-fuel ratio.

[0035] Specifically, the method is as follows: First, calculate the initial ideal air-fuel ratio: The gas composition changes are detected in real time by the gas calorimeter arranged on the gas main pipeline 1. Generally, the CO content fluctuates between 20% and 30%, with a fluctuation range of ±3% to ±5%, the H2 content fluctuates between 1% and 5%, with a fluctuation range of ±1% to ±2%, the CO2 content fluctuates between 15% and 25%, with a fluctuation range of ±3% to ±5%, the N2 content fluctuates between 40% and 60%, with a fluctuation range of ±3% to ±5%, and the CH4 content fluctuates between 0.2% and 0.5%. According to the CO, H2, CH4 combustion equation: 2CO + O2 = 2CO2, 1 volume of CO needs 0.5 volume of oxygen for complete combustion, 2H2 + O2 = 2H2O, 1 volume of H2 needs 0.5 volume of oxygen for complete combustion, CH4 + 2O2 = CO2 + 2H2O, 1 volume of CH4 needs 2 volumes of oxygen for complete combustion, O2 content in combustion air is 21%, Therefore, the ideal air-fuel ratio = (0.5*g + 0.5*h + 2*i) / 0.21; Wherein, g is the volume content of H2 in the gas, h is the volume content of CO in the gas, and i is the volume content of CH4 in the gas.

[0036] Then, calculate the residual oxygen correction factor: Install a residual oxygen analyzer at the outlet pipeline of the hot blast stove to monitor the oxygen content after combustion, judge the combustion sufficiency, and judge the combustion air supply condition according to the detection value. The normal range is set to 3%~6%, and the residual oxygen value is taken as an example. If the residual oxygen is higher than 6%, the combustion air is excessive, and the air-fuel ratio needs to be reduced. If the residual oxygen is lower than 3%, the combustion air is insufficient, and the air-fuel ratio needs to be increased. Residual oxygen correction factor calculation formula: Residual oxygen correction factor = 1 + (actual residual oxygen value - best residual oxygen intermediate value) * 0.1; When the residual oxygen value is 4%, the residual oxygen correction factor = 1 + (4% - 4.5%) * 0.1 = 0.995; Finally, calculate the corrected air-fuel ratio according to the following formula: Corrected air-fuel ratio = ideal air-fuel ratio * residual oxygen correction factor; Assuming that the initial value of the ideal air-fuel ratio calculated by the gas composition is 0.695, the corrected air-fuel ratio = ideal air-fuel ratio * residual oxygen correction factor = 0.695 * 0.995 ≈ 0.691. By combining the gas composition and residual oxygen to control the air-fuel ratio, the combustion efficiency and stability are guaranteed, and the energy utilization rate is improved. To determine the total correction range of the air-fuel ratio, the combustion equipment parameters, gas properties and production process requirements should also be considered. In actual application, in order to ensure complete combustion, an excess combustion air factor of 1.05~1.2 will be multiplied.

[0037] e. Combustion execution: distribute the total gas target flow to the plurality of burners to obtain the gas target flow of each burner, and calculate the corresponding combustion air target flow of each burner according to the corrected air-fuel ratio, and then control the opening degree of the gas flow regulating valve and the combustion air flow regulating valve of each burner to adjust the supply amount of gas and combustion air.

[0038] Specifically, the calculated total target flow of the coal gas is reasonably distributed to each burner according to the actual state of each burner (whether it is working normally, whether it is blocked, etc.), to determine the target flow of the coal gas of each burner, and the step of distributing the total target flow of the coal gas to each burner specifically comprises: First, preset an optional control mode for each burner, and the optional control mode includes an automatic control mode, a follow-up control mode and a manual control mode; Count the number N of burners in the automatic control mode and the total sum F of the coal gas flow of the burners in the follow-up or manual control mode; According to the formula: burner coal gas target flow = (total target flow of coal gas - F) / N, the target flow of the coal gas of each burner in the automatic control mode is calculated and distributed. This mechanism realizes fault-tolerant control: when a burner fails or needs manual intervention, it can be switched out of the automatic control mode, and the system will automatically adjust the load of other normal burners to ensure uninterrupted production.

[0039] Secondly, according to the relationship between the target flow of the coal gas of the burner and the measured flow of the coal gas of the burner, i.e. the actual flow of the coal gas of the burner, and the air-fuel ratio relationship between the combustion-supporting air flow of the burner and the coal gas flow, the opening degree of the coal gas flow regulating valve and the opening degree of the combustion-supporting air flow regulating valve are adjusted, and the adjustment mode is divided into three categories: the adjustment of the opening degree of the coal gas flow regulating valve and the opening degree of the combustion-supporting air flow regulating valve in the automatic control mode, the follow-up control mode and the manual control mode.

[0040] Specifically, a group of burner coal gas flow meters are arranged on the coal gas branch pipelines of each burner to detect the measured flow of the coal gas of the burner, and a group of burner combustion-supporting air flow meters are arranged on the combustion-supporting air branch pipelines of each burner to detect the measured flow parameter of the combustion-supporting air of the burner. The detailed control rules are as follows: When the burner is in the automatic control mode: If the burner is in the automatic control mode, the opening degree of the corresponding coal gas flow regulating valve of the burner is adjusted based on the relationship between the target flow of the coal gas and the measured flow of the coal gas of the burner, and the opening degree of the corresponding combustion-supporting air flow regulating valve is adjusted based on the corrected air-fuel ratio relationship between the measured flow of the combustion-supporting air of the burner and the measured flow of the coal gas of the burner; In detail, the adjustment method of the coal gas flow regulating valve of each burner is as follows: If the target flow of the coal gas of the burner > the measured flow of the coal gas of the burner x a1, then the opening degree of the coal gas flow regulating valve is increased, where a1 is the first burner coal gas flow adjustment coefficient, and in this embodiment, a1 = 1.05. At this time, the opening degree of the coal gas flow regulating valve is increased by 0.8; If the target flow of the coal gas of the burner < the measured flow of the coal gas of the burner x a2, then the opening degree of the coal gas flow regulating valve is decreased, where a2 is the second burner coal gas flow adjustment coefficient, and in this embodiment, a2 = 0.95. At this time, the opening degree of the coal gas flow regulating valve is decreased by 0.8; The adjustment method of the combustion air flow regulating valve of each burner is as follows: If the burner combustion air flow > burner gas measured flow x corrected air fuel ratio x β1, then control the combustion air flow regulating valve opening to decrease, wherein β1 is the first burner combustion air flow regulating coefficient, in this embodiment, β1 = 1.1, at this time, control the regulating valve opening to decrease by 0.7; If the burner combustion air flow < burner gas measured flow x corrected air fuel ratio x β2, then control the combustion air flow regulating valve opening to increase, wherein β2 is the first burner combustion air flow regulating coefficient, in this embodiment, β2 = 0.9, at this time, control the regulating valve opening to increase by 0.7; The above adjustment frequency is once every five seconds, which can be adjusted according to actual conditions.

[0041] When the burner is in the follow-up control mode: If the burner is in the follow-up control mode, the opening of the gas flow regulating valve corresponding to the burner is manually set based on the gas measured flow, and the opening of the combustion air flow regulating valve corresponding to the burner is adjusted based on the relationship between the burner combustion air measured flow and the corrected air fuel ratio of the burner gas measured flow; The specific rules are as follows: If the burner combustion air measured flow > burner gas measured flow x corrected air fuel ratio x β1, then control the combustion air flow regulating valve opening to decrease, wherein β1 is the first burner combustion air flow regulating coefficient, in this embodiment, β1 = 1.1, at this time, control the regulating valve opening to decrease by 0.7; If the burner combustion air flow < burner gas measured flow x corrected air fuel ratio x β2, then control the combustion air flow regulating valve opening to increase, wherein β2 is the first burner combustion air flow regulating coefficient, in this embodiment, β2 = 0.9, at this time, control the regulating valve opening to increase by 0.7.

[0042] When the burner is in the manual control mode: The openings of the gas flow regulating valve and the combustion air flow regulating valve both need to be adjusted by the operator manually, that is, the gas flow regulating valve is manually adjusted in opening size based on the gas measured flow, and the combustion air flow regulating valve is manually adjusted in opening size based on the relationship between the corrected air fuel ratio of the gas measured flow and the combustion air flow.

[0043] Through the above-mentioned coordinated adjustment mode of the gas and combustion air flow of each burner, it is ensured that each burner can burn under the appropriate gas and appropriate gas and combustion air supply ratio, thereby realizing the continuous and stable hot air supply of the hot blast furnace for the slag grinding mill.

[0044] In the entire control process of the hot blast furnace and the slag grinding mill, there is also stable pressure control for the gas and stable pressure control for the combustion air, specifically: Gas pressure stabilization control includes: A gas pressure sensor and a gas pressure regulating valve are installed on the main gas pipeline. The gas pressure is monitored in real time by the gas pressure sensor, and the opening of the gas pressure regulating valve is adjusted by a PID closed-loop control algorithm to stabilize the gas pressure after the valve within the preset target pressure range. Combustion air pressure stabilization control includes: A combustion air pressure sensor is installed on the combustion air outlet pipe, i.e., the main combustion air pipe, to monitor the motor speed of the combustion air blower in real time. Similarly, through a PID closed-loop control algorithm, the motor speed of the combustion air blower is adaptively adjusted according to the detected combustion air pressure on the main combustion air pipe to ensure that the combustion air pressure on the main combustion air pipe is within the preset pressure range.

[0045] This invention also discloses an automatic combustion control system for a hot blast stove of a slag grinding mill, such as... Figure 2 As shown, it includes: The data acquisition unit is configured to collect the operating parameters of the hot blast stove and the slag grinding mill in real time. The operating parameters of the hot blast stove include furnace temperature, furnace pressure, blast furnace gas composition, gas flow rate of each burner, combustion air flow rate of each burner, and residual oxygen content in the flue gas. The operating parameters of the slag grinding mill include mill main motor current, cold air valve opening degree, and circulating air valve opening degree. The execution unit includes multiple burner gas flow regulating valves 7 for regulating the gas flow rate of each burner gas pipeline and multiple burner combustion air flow regulating valves 14 for regulating the combustion air flow rate of each burner combustion air pipeline. The controller 28 is communicatively connected to the data acquisition unit and the actuator unit, and the controller 28 is configured to execute the above-described automatic combustion control method for a hot blast stove of a slag grinding mill.

[0046] Specifically, the data acquisition unit comprises: a gas calorimeter 2 installed on the gas main pipeline 1 for detecting the gas composition, a gas pressure sensor 4 for monitoring the pressure, a burner gas flow meter 6 and a burner combustion air flow meter 13 installed on each burner gas branch pipeline 5 and burner combustion air branch pipeline 12 respectively, a hearth temperature sensor 16 installed on the hot blast stove 15 body for measuring the hearth temperature, a hearth pressure sensor 17 for measuring the hearth pressure, a residual oxygen analyzer 18 installed at the hot blast stove outlet flue for detecting the residual oxygen content of flue gas, the total flow of the blast furnace gas is calculated by measuring the gas flow value on each burner branch pipeline 5 through a plurality of sets of burner gas flow meters 6, and the unit also acquires key parameters of the slag grinding mill 21 system linked with the hot blast stove 15, such as the current of the grinding main motor 21, the opening size of the cold air valve 19 and the circulating air valve 20, etc. These data are transmitted in real time to the controller 28 through a high-speed bus to provide the basis for intelligent decision-making, and the typical sampling interval time of each parameter is set according to its change characteristics, which can be specifically according to the sampling interval time in the following table: Table 1 Setting details of sampling interval time The execution unit is responsible for executing the instructions issued by the controller 28, including the pressure stabilizing valve 3 arranged on the gas main pipeline 1, the burner gas flow regulating valve 7 arranged on each burner gas branch pipeline 5, the burner combustion air flow regulating valve 14 arranged on each burner combustion air branch pipeline 12, the cold air valve 19, the circulating air valve 20 and the motor of the combustion air fan 9.

[0047] The controller 28 integrates the control algorithm and logic described in the present application, including a control mode selection module, a target flow calculation module, an air-fuel ratio correction module and a burner control module.

[0048] Specifically, the control mode selection module is used to select between the furnace temperature control mode and the flow control mode according to the production stage of the slag grinding mill 27. According to the hearth temperature measured by the hearth temperature sensor 16, in this embodiment, when the hearth temperature in the hot blast stove 15 is controlled at 1050℃, the flow control mode is entered, otherwise, the furnace temperature control mode is entered.

[0049] a target flow calculation module for calculating a total target flow of the gas according to the selected control mode, the target flow calculation module comprising a furnace temperature control submodule and a flow control submodule, wherein the furnace temperature control submodule is configured to calculate the total target flow of the gas based on a temperature deviation ΔT and a temperature rise change ΔP in the furnace temperature control mode, and to determine whether a demand temperature set value changes in the furnace temperature control mode, and when the demand temperature set value does not change, to calculate the total target flow of the gas according to a formula: total target flow of gas = original total target flow of gas + (ΔT + ΔP) × K1, wherein K1 is a preset gas flow adjustment coefficient, and when the demand temperature set value changes, to calculate the total target flow of the gas according to a formula: ΔS = new temperature demand set value - original temperature demand set value, total target flow of gas = original total target flow of gas + ΔS × K2, wherein K2 is a preset temperature change response coefficient, and K1 > K2; and the flow control submodule, which contains a linkage rule base inside, is configured to adjust and determine the total target flow of the gas based on a combination state of a main motor current of the mill, an opening degree of the circulating air valve and an opening degree of the cold air valve according to the linkage rule base in the flow control mode.

[0050] an air-fuel ratio correction module for calculating a corrected air-fuel ratio based on the composition of the blast furnace gas and the residual oxygen value of the exhaust gas, specifically, a gas calorific value analyzer 2 arranged on a gas main pipe 1 is used to monitor the change in the composition of the gas in real time, an ideal air-fuel ratio is calculated according to the combustion equations of CO, H2 and CH4, a residual oxygen analyzer 18 arranged on an exhaust gas outlet pipe of the hot blast stove 15 is used to monitor the actual residual oxygen value after combustion in real time, an optimal residual oxygen intermediate value is determined according to a preset optimal residual oxygen value range, a residual oxygen correction factor is calculated according to a formula: residual oxygen correction factor = 1 + (actual residual oxygen value - optimal residual oxygen intermediate value) × 0.1, and finally a corrected air-fuel ratio is calculated according to a formula: corrected air-fuel ratio = ideal air-fuel ratio × residual oxygen correction factor.

[0051] a burner control module for distributing the total target flow of the gas to a plurality of burners and controlling the supply of the gas and combustion-supporting air to each burner according to the corrected air-fuel ratio; Specifically, the burner control module function realizes precise control of each burner, ensuring uniform combustion and stable heating. The hot blast stove 15 provided on site is equipped with three burners 8, and each burner can be set to three modes: manual control (burner combustion-supporting air flow regulating valve 14 and burner gas flow regulating valve 7 are manually set), automatic control (burner combustion-supporting air flow regulating valve 14 and burner gas flow regulating valve 7 are automatically adjusted), and follow-up control (burner gas flow regulating valve 7 opening degree is manually adjusted, and burner combustion-supporting air flow regulating valve 14 is automatically adjusted according to the corrected air-fuel ratio). Burner gas flow meter 6 and burner combustion-supporting air flow meter 13 are respectively arranged on burner gas branch pipe 5 and burner combustion-supporting air branch pipe 12. When an abnormal condition occurs in a certain burner 8, the abnormal burner 8 can be controlled individually. Specifically, it can be set to manual control mode, follow-up control mode, or directly shut down. In this process, the following parameters are set: N: represents the number of burners in automatic control state; F: represents the gas flow corresponding to the burner in manual or follow-up control state; The gas target flow calculation formula of the burner 8 in automatic control mode is: burner gas target flow = (gas target flow - F) ÷ N. The function of this formula is to eliminate the influence of abnormal burners on automatic combustion, so as to accurately determine the target flow allocated to the remaining automatic control burners.

[0052] More specifically, in automatic control mode, the opening degree of burner gas flow regulating valve 7 is automatically adjusted based on the burner gas target flow and the burner gas measurement flow measured by burner gas flow meter 6, and the opening degree of burner combustion-supporting air flow regulating valve 14 is automatically adjusted based on the corrected air-fuel ratio of burner gas measurement flow and burner combustion-supporting air measurement flow. In follow-up control mode, the operator manually sets the opening degree of each burner gas flow regulating valve 7, the opening degree of burner gas flow regulating valve 7 is manually adjusted based on the gas measurement flow, and the opening degree of burner combustion-supporting air flow regulating valve 14 is automatically adjusted based on the corrected air-fuel ratio of burner gas measurement flow and combustion-supporting air measurement flow. In manual mode, the opening degree of burner gas flow regulating valve 7 and burner combustion-supporting air flow regulating valve 14 needs to be manually set and adjusted by the operator, the opening degree of burner gas flow regulating valve 7 is based on the burner gas measurement flow, and the opening degree of burner combustion-supporting air flow regulating valve 14 is based on the corrected air-fuel ratio of burner gas measurement flow and combustion-supporting air flow.

[0053] The control system further comprises a gas pressure stabilizing module and a combustion air pressure stabilizing module. The gas pressure stabilizing module comprises a pressure stabilizing valve 3 and a gas pressure sensor 4 arranged on the gas main pipeline 1, both of which are signal connected with the controller 28. The gas pressure is monitored in real time by the gas pressure sensor 4, and a PID closed-loop control algorithm is adopted to adjust the opening degree of the pressure stabilizing valve 3, so that the gas pressure after the valve is stabilized in a preset target pressure range. The combustion air pressure stabilizing module comprises a combustion air pressure sensor 11 arranged on the combustion air main pipeline 10, the combustion air pressure sensor 11 is signal connected with the signal input end of the controller 28, and the motor of the combustion air fan 9 is signal connected with the signal output end of the controller 28. The combustion air pressure on the combustion air main pipeline 10 is monitored in real time by the combustion air pressure sensor 11, and a PID closed-loop control algorithm is also adopted to adjust the rotating speed of the motor of the combustion air fan 9, so as to ensure that the combustion air pressure is kept in a preset range.

[0054] In addition, a gas quick cut valve 29 is arranged on the gas main pipeline 1, the gas quick cut valve 29 is signal connected with the controller 28, a flame detector 30 is arranged on the hot blast stove 15, a nitrogen pressure sensor 32 is arranged on the nitrogen main pipeline 31, the flame detector 30 and the nitrogen pressure sensor 32 are signal connected with the signal input end of the controller 28, and a safety interlocking logic is preset in the controller 28 in a programmed form. The safety interlocking logic comprises: when at least one of the following conditions is detected, the controller 28 alarms and automatically closes the gas quick cut valve 29 on the gas main pipeline 1: flameout, low gas pressure, low combustion air pressure, or abnormal furnace temperature. Flameout interlocking: once the flame detector 30 on the hot blast stove 15 cannot sense the flame signal, the signal is quickly transmitted to the control system, and the controller 28 issues an instruction to close the gas quick cut valve 29. Gas pressure interlocking: when the pressure sensor 4 on the gas main pipeline 1 detects that the pressure is lower than 3.0 Kpa, the controller 28 alarms; when the pressure is lower than 2.5 Kpa and lasts for 3 seconds, the controller 28 automatically closes the gas quick cut valve 29 to cut off the gas supply. Combustion air pressure interlocking: when the combustion air pressure measured by the combustion air pressure sensor 11 is lower than 2.5 Kpa, the controller 28 alarms; when the combustion air pressure is lower than 2.0 Kpa and lasts for 3 seconds, the controller 28 closes the gas quick cut valve 29 to ensure safety. Valve gas source pressure (nitrogen): when the nitrogen pressure measured by the nitrogen pressure sensor 32 on the nitrogen main pipeline 31 is lower than 0.3 Mpa, the controller 28 alarms; when the nitrogen pressure is lower than 0.25 Mpa and lasts for 3 seconds, the controller 28 issues an instruction to close the gas quick cut valve 29. High furnace temperature interlocking: under normal operating conditions, when the temperature of the hot blast stove furnace is lower than 750℃ and lasts for 6 minutes, the controller 28 issues an instruction to close the gas quick cut valve 29.

[0055] The above examples are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions recorded in the foregoing examples can be modified, or some technical features can be replaced by equivalent features; and these modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present application.

Claims

1. An automatic combustion control method for a hot blast stove in a slag grinding mill, applied to a system including a hot blast stove and a slag grinding mill linked to the hot blast stove, wherein the hot blast stove has multiple burners, characterized in that... Includes the following steps: a. Data Acquisition: The operating parameters of the hot blast stove and the slag grinding mill are collected. The operating parameters of the hot blast stove include at least the furnace temperature, furnace pressure, blast furnace gas composition, gas flow rate of each burner, combustion air flow rate of each burner, and residual oxygen content in the flue gas. The operating parameters of the slag grinding mill include at least the main motor current, cold air valve opening, and circulating air valve opening. b. Select control mode: According to the production stage of the hot blast stove, select one of at least two preset control modes to execute. The control modes include a furnace temperature control mode for the furnace start-up, baking or heat preservation stage, and a flow control mode for the production stage linked with the slag grinding mill. c. Calculate the target flow rate: If the furnace temperature control mode is currently selected, the total target flow rate of the gas is calculated based on the temperature deviation ΔT between the preset required temperature and the collected furnace temperature and the temperature rise change ΔP of the furnace temperature during the sampling period. If the current selected flow control mode is the flow control mode, the total target flow of gas is adjusted and determined according to the combination of the mill main motor current, the opening degree of the circulating air valve and the opening degree of the cold air valve, based on the preset linkage rule library. d. Air-fuel ratio correction: The ideal air-fuel ratio is calculated based on the real-time collected blast furnace gas composition, and a residual oxygen correction factor is calculated based on the residual oxygen value of the exhaust gas. The ideal air-fuel ratio is multiplied by the residual oxygen correction factor to obtain the corrected air-fuel ratio; e. Combustion execution: The total target flow rate of the gas is evenly distributed to multiple burners to obtain the target flow rate of the gas for each burner. The target flow rate of the combustion air for each burner is calculated based on the corrected air-fuel ratio. The opening degree of the gas flow regulating valve and the combustion air flow regulating valve of each burner is then controlled to regulate the supply of gas and combustion air.

2. The automatic combustion control method for the hot blast stove of the slag grinding mill according to claim 1, characterized in that, In step c, the step of calculating the total target flow rate of the gas under the furnace temperature control mode specifically includes: When the required temperature setting remains unchanged, the total target flow rate of the gas is calculated using the following formula: Target total flow rate of coal gas = Total target flow rate of raw coal gas + (ΔT + ΔP) × K1, Wherein, K1 is the preset gas flow rate adjustment coefficient; When the required temperature setting changes, the total target gas flow rate is calculated using the following formula: ΔS = New required temperature setpoint - Original required temperature setpoint Target total flow rate of coal gas = Total target flow rate of raw coal gas + ΔS × K2 Wherein, K2 is the preset temperature change response coefficient; And K1 > K2.

3. The automatic combustion control method for the hot blast stove of the slag grinding mill according to claim 1, characterized in that, In step c, under the flow control mode, the linkage rule base includes at least one of the following rules: When the opening of the circulating air valve is greater than or equal to the first threshold and the opening of the cold air valve is less than or equal to the second threshold, the total target flow rate of the gas is adjusted according to the change in the opening of the cold air valve or the change trend of the mill main motor current. When the opening degree of the circulating air valve is less than or equal to the third threshold and the opening degree of the cold air valve is less than or equal to the fourth threshold, the total target flow rate of the gas is adjusted according to the change or absolute value of the main motor current of the mill. When the instantaneous current of the main motor of the mill exceeds the preset overload protection threshold, the total target flow rate of the gas is significantly increased.

4. The automatic combustion control method for the hot blast stove of the slag grinding mill according to claim 1, characterized in that, In step d, the specific steps for air-fuel ratio correction include: The volume content of combustible components (including CO, H2, and CH4) in the blast furnace gas is detected in real time using a calorific value analyzer, and the ideal air-fuel ratio is calculated based on the chemical combustion equation. The residual oxygen value in the flue gas after combustion is detected by a residual oxygen analyzer. When the residual oxygen value deviates from the preset optimal range, the residual oxygen correction factor is calculated according to the formula: residual oxygen correction factor = 1 + (actual residual oxygen value - optimal residual oxygen median value) × 0.

1. Multiplying the ideal air-fuel ratio by the residual oxygen correction factor yields the corrected air-fuel ratio used for combustion control.

5. The automatic combustion control method for the hot blast stove of the slag grinding mill according to claim 1, characterized in that, In step e, the step of allocating the total target flow rate of the gas specifically includes: Each burner has a preset selectable control mode, which includes automatic control mode, follow-up control mode and manual control mode; According to the formula: Burner gas target flow rate = (total gas target flow rate - F) / N, calculate and allocate the gas target flow rate for each burner in automatic control mode; Where N is the number of burners in automatic control mode, and F is the total gas flow rate of burners in servo or manual control mode.

6. The automatic combustion control method for the hot blast stove of the slag grinding mill according to claim 5, characterized in that, In step e, the control methods for the gas flow regulating valve and the combustion air flow regulating valve of each burner under different control modes are as follows: If the burner is in automatic control mode, the opening of the gas flow regulating valve corresponding to the burner is automatically adjusted based on the target gas flow and the measured gas flow of the burner, and the opening of the combustion air flow regulating valve is automatically adjusted based on the corrected air-fuel ratio relationship between the measured combustion air flow and the measured gas flow of the burner. If the burner is in follow-up control mode, the opening of the gas flow regulating valve corresponding to the burner is manually set based on the measured gas flow, and the opening of the corresponding combustion air flow regulating valve is automatically adjusted based on the corrected air-fuel ratio relationship between the measured combustion air flow and the measured gas flow of the burner. If the burner is in manual control mode, the opening of the gas flow regulating valve corresponding to the burner is manually adjusted based on the measured gas flow rate, and the opening of the combustion air flow regulating valve corresponding to the burner is manually set based on the relationship between the measured gas flow rate and the corrected air-fuel ratio.

7. The automatic combustion control method for the hot blast stove of a slag grinding mill according to claim 6, characterized in that, In step e, the adjustment method for the gas flow regulating valve corresponding to the burner in automatic control mode is as follows: If the target flow rate of the burner gas is greater than the measured flow rate of the burner gas × α1, then the opening of the control gas flow regulating valve will be increased. If the target flow rate of the burner gas is less than the measured flow rate of the burner gas × α2, then the opening of the control gas flow regulating valve should be reduced. The adjustment methods for the combustion air flow regulating valves corresponding to the burners in automatic control mode and follow-up control mode are as follows: If the measured flow rate of the combustion air for each burner is greater than the measured flow rate of the gas for each burner × the corrected air-fuel ratio × β1, then the opening of the control valve for the combustion air flow rate is reduced. If the measured flow rate of the combustion air for each burner is less than the measured flow rate of the gas for each burner × the corrected air-fuel ratio × β2, then the opening of the control valve for the combustion air flow rate should be increased. Where α1 and α2 are the preset gas flow rate adjustment coefficients for the first burner and the second burner, respectively, and β1 and β2 are the preset combustion air flow rate adjustment coefficients for the first burner and the second burner, respectively.

8. The automatic combustion control method for the hot blast stove of a slag grinding mill according to claim 1, characterized in that, It also includes a gas pressure stabilization step before the blast furnace gas enters the burner: Install gas pressure sensors and pressure regulating valves on the main gas pipeline; The gas pressure is monitored in real time by the gas pressure sensor, and the opening of the pressure stabilizing valve is adjusted by a PID closed-loop control algorithm to keep the gas pressure after the valve stable within the preset target pressure range.

9. An automatic combustion control system for a hot blast stove of a slag grinding mill, applied to a system including a hot blast stove and a slag grinding mill linked to the hot blast stove, wherein the hot blast stove has multiple burners, characterized in that, include: The data acquisition unit is configured to collect the operating parameters of the hot blast stove and the slag grinding mill in real time. The operating parameters of the hot blast stove include furnace temperature, furnace pressure, blast furnace gas composition, gas flow rate of each burner, combustion air flow rate of each burner, and residual oxygen content in the flue gas. The operating parameters of the slag grinding mill include mill main motor current, cold air valve opening degree, and circulating air valve opening degree. The execution unit includes at least a plurality of gas flow regulating valves for regulating the gas flow rate of each burner gas branch pipeline and a plurality of combustion air flow regulating valves for regulating the combustion air flow rate of each burner combustion air branch pipeline. A controller, communicatively connected to the data acquisition unit and the actuator unit, is configured to perform the method as described in any one of claims 1 to 8.

10. The automatic combustion control system for the hot blast stove of the slag grinding mill according to claim 9, characterized in that, The controller includes: The control mode selection module is used to select between furnace temperature control mode and flow control mode according to the production stage of the hot blast stove; The target flow calculation module is used to calculate the total target flow of gas based on the selected control mode. The air-fuel ratio correction module is used to calculate the corrected air-fuel ratio based on the blast furnace gas composition and the residual oxygen value of the exhaust gas. The burner control module is used to distribute the total target flow rate of the gas to multiple burners and control the combustion process according to the corrected air-fuel ratio.

11. The automatic combustion control system for the hot blast stove of the slag grinding mill according to claim 9, characterized in that, The target traffic calculation module includes: The furnace temperature control submodule is configured to calculate the total target flow rate of the gas based on the temperature deviation and temperature rise change in the furnace temperature control mode. The flow control submodule contains a linkage rule library, which is configured to adjust and determine the total target flow rate of the gas based on the combination of the mill main motor current, the opening degree of the circulating air valve and the opening degree of the cold air valve in the flow control mode.

12. The automatic combustion control system for the hot blast stove of the slag grinding mill according to claim 9, characterized in that, The burner control module is also configured to: Each burner can be independently set to automatic, follow-up, or manual control mode; When a burner is detected to be in non-automatic control mode, the remaining gas flow is dynamically and evenly distributed to the burners in automatic control mode after the total target gas flow is subtracted from the gas flow corresponding to the burners in manual or follow-up mode.

13. The automatic combustion control system for the hot blast stove of the slag grinding mill according to claim 9, characterized in that, The controller is also configured to: The system is equipped with a safety interlock logic, which includes: when at least one of the following conditions is detected: flameout, low gas pressure, low combustion air pressure, or abnormal furnace temperature, an alarm is triggered and the gas quick-cut valve on the main gas pipeline is automatically shut off.

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