Linkage control method and system for emergency shutdown of blast furnace

Abstract

The present application belongs to the technical field of blast furnace blowdown, and particularly relates to a linkage control method and system for emergency blowdown of a blast furnace. The method responds to an emergency blowdown instruction of a blast furnace foreman, synchronously links hot blast furnace, bag dust removal, air blower and other systems, confirms the closing of the air mixing valve, controls the opening degree of the cold air valve and the manual opening of the pressure reducing valve group to a preset value, stops the combustion of the hot blast furnace and closes the furnace. The hot blast pressure and the descending rate are monitored in real time, the pressure reducing valve is fully opened after reaching the standard, the interval is dynamically adjusted according to the top pressure, and the opening degree of the cold air valve is increased to a third preset value. After the cold air valve is in place, the diffuser valve is fully opened. After the diffuser valve is in place, the gas cut-off valve is closed, and the downstream pressure is monitored to verify the cut-off. Finally, the cold air valve is fully opened, the air blower is stopped, and nitrogen blowing is started to complete the blowdown. The present application realizes linkage of multiple systems, dynamically adjusts the opening degree of the pressure reducing valve and the cold air valve, adapts to the change of the top pressure, and ensures the safety of pressure reduction. The downstream pressure verification after gas cut-off ensures the blockage of the passage, and improves the efficiency and safety of emergency blowdown.

Description

Technical Field

[0001] This invention belongs to the field of blast furnace shutdown technology, specifically relating to a linkage control method and system for emergency shutdown of a blast furnace. Background Technology

[0002] Emergency shutdown of a blast furnace refers to the operation that requires the rapid cessation of blasting and charging, and the transition of the blast furnace to a safe operating state, due to emergency reasons such as fan shutdown, water shortage, or gas leakage during blast furnace production.

[0003] Emergency shutdowns involve multiple systems, and the operation of these subsystems requires unified coordination and strict timing constraints. Inconsistent coordination can easily lead to system problems. For example, premature shutdown of the blower system can cause pressure imbalance in the hot air system, resulting in hot air backflow into the blower and causing equipment damage. A lack of synchronization between the pulverized coal injection system and the coke oven system can lead to situations where pulverized coal injection continues even after feeding has stopped, exacerbating temperature imbalances within the furnace and further disrupting furnace conditions.

[0004] When processing pressure and rate, related technologies cannot identify the correlation between pressure and rate changes, making it difficult to predict the direction of pressure evolution within the furnace. Intervention is often delayed until abnormal conditions have already occurred, missing the optimal adjustment window. Furthermore, during the high-pressure phase of the blast furnace, an excessively narrow rate threshold leads to a slow pressure reduction pace, prolonging emergency shutdown times and increasing the duration of dangerous conditions within the furnace. During the low-pressure phase, the burden column loses gas support, causing changes in the friction angle between particles and potentially leading to collapse accidents. Moreover, monitoring only a single pressure value fails to capture pressure change trends, easily resulting in misjudgments and untimely adjustments.

[0005] The pressure and rate status is judged by numerical comparison to determine whether the conditions are met. When the pressure or rate deviates slightly, adjustments are performed. However, due to the inability to accurately adapt to different deviations in the working conditions, the adjustment accuracy is insufficient, which can easily lead to over-adjustment or under-adjustment, affecting the stability of the pressure relief process. Summary of the Invention

[0006] This invention provides a linkage control method for emergency blast furnace shutdown, achieving automated linkage and dynamic pressure-rate dual-parameter control to improve safety. This invention ensures that each step is executed correctly, shortening shutdown time while reducing equipment damage and safety risks.

[0007] The methods include: S1: In response to the emergency shutdown command issued by the blast furnace foreman, send an emergency shutdown linkage signal, execute the operation of closing the oxygen-enriched shut-off valve, prohibiting the opening of the lower pressure valve, prohibiting the charging operation, and closing the mixing air shut-off valve, and monitor the execution feedback status of the oxygen-enriched shut-off valve and the mixing air shut-off valve in real time. S2: After confirming that the execution feedback status of the mixed air shut-off valve is closed, the blast furnace shutdown control module determines the first target opening degree of the cold air release valve based on the current real-time monitored blast furnace hot blast pressure value and controls it to open to the first target opening degree. After controlling the pressure reducing valve group to switch to manual mode, it opens to the second preset opening degree and sends a command to the hot blast stove system to control the hot blast stove system to perform the shutdown combustion and furnace shut-off operation. S3: Continuously monitor the hot blast pressure value and hot blast pressure drop rate of the blast furnace in real time, and determine whether the hot blast pressure value is lower than the first set pressure threshold and whether the hot blast pressure drop rate is within the preset safe rate range; if both conditions are met at the same time, proceed to step S4. S4: After confirming that the hot air pressure value is lower than the first set pressure threshold and the hot air pressure drop rate is within the preset safe rate range, control the pressure reducing valve group to perform a full opening operation, and control the cold air vent valve to gradually increase the opening degree according to the preset time interval gradient until the opening degree of the cold air vent valve reaches the third preset opening degree. S5: When the opening degree of the cold air vent valve is detected to reach the third preset opening degree and the pressure inside the blast furnace drops below the second set pressure threshold, the top steam valve is opened. After confirming that the execution feedback state of the top steam valve is in the fully opened position, the top vent valve is opened to the fully open position. S6: After confirming that the execution feedback status of the furnace top vent valve is in the open position, control the gas shut-off valve to perform the closing operation and monitor the gas pressure value downstream of the gas shut-off valve in real time. S7: After confirming that the gas shut-off valve is closed and the gas pressure downstream of the gas shut-off valve has dropped to the preset safe pressure range, control the cold air release valve to open to the fully open position, send a shutdown command to the blower system, and start the nitrogen purging operation at the furnace top to complete the emergency shutdown process of the blast furnace.

[0008] According to another embodiment of this application, a linkage control system for emergency shutdown of a blast furnace is provided, including: a blast furnace shutdown control module, a hot blast stove system, a blower system, a TRT system, a bag filter dust collector system, furnace top equipment, a ore and coke bin system, a pulverized coal injection system, and a water system; The blast furnace shutdown control module is connected to the hot blast stove system, blower system, TRT system, bag filter dust collector system, furnace top equipment, ore and coke bin system, pulverized coal injection system and water system respectively; The coke oven system and the pulverized coal injection system form the feed branch to the furnace; the blower system and the hot blast stove system form the air supply branch; the furnace top equipment, the TRT system and the bag filter system form the gas treatment branch; and the water system is the common cooling branch for the entire system. The blast furnace shutdown control module executes the emergency shutdown linkage control of the blast furnace according to the sequence of cutting off the material first, then cutting off the heat, then treating the gas, and finally stopping the blast.

[0009] As can be seen from the above technical solutions, the present invention has the following advantages: The linkage control method for emergency shutdown of blast furnace provided by this invention sets up a blast furnace shutdown control module as a unified control to address the linkage problem of various subsystems. It synchronously sends emergency shutdown linkage signals to 8 subsystems, clarifies the action sequence of each subsystem, and sets up forced interlocks for each subsystem in the manner of cutting off material first, then cutting off heat, then treating gas, and finally stopping the blast. It also monitors the execution feedback status of key valves in real time.

[0010] This invention constructs a safety rate function with the current hot air pressure as the independent variable, generating a safety rate envelope interval that dynamically contracts as the pressure decreases. A two-dimensional state-space coordinate system is constructed, mapping pressure and rate to discrete points to form a trajectory curve. This divides the system into four operating regions, executing corresponding branch processing logic for each region, and fine-tuning the opening of the cold air vent valve in real time using a proportional adjustment algorithm.

[0011] This invention calculates a dynamic scaling factor based on the historical pressure fluctuation range and performs dimensionless standardization on pressure and velocity data. A circular trajectory buffer is constructed to store historical coordinate points, and the Euclidean distance, orientation angle, and trajectory curvature of adjacent points are calculated. A trajectory classifier is then used to match a stable pressure drop standard template to capture trajectory features and evolution trends.

[0012] This invention addresses the timing risk of venting at the furnace top by setting dual-parameter trigger conditions: the opening degree of the cold air venting valve and the furnace internal pressure. The furnace top steam valve is only opened when both parameters meet the requirements. A hard logic interlock is implemented between the steam valve and the venting valve. After confirming that the steam valve is fully open, the furnace top venting valve is controlled to open, while simultaneously monitoring the steam pipeline pressure to ensure effective steam curtain formation.

[0013] This invention controls the gas shut-off valve to close and monitors the downstream gas pressure in real time. The shut-off effect is verified by pressure changes, and the shut-off is confirmed only when the pressure drops to a preset safe range. The invention also controls the opening of the cold air vent valve at preset time intervals. During this gradient adjustment, the furnace top pressure is monitored in real time. The preset time interval is dynamically adjusted based on the deviation and rate of change between the furnace top pressure and the target pressure to adapt to dynamic pressure changes within the furnace. The two-dimensional state space is divided into four distinct operating zones, each with its own processing logic. Differentiated adjustments are made based on the zone and deviation of the state point, using a proportional adjustment algorithm to quantify the opening correction, improving adjustment accuracy and enhancing the stability and safety of emergency shutdown processes. Attached Figure Description

[0014] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 A schematic diagram of the linkage control system for an emergency shutdown of a blast furnace; Figure 2 A flowchart of the linkage control method for emergency shutdown of blast furnace; Figure 3 A flowchart illustrating an implementation method for the linkage control of an emergency shutdown of a blast furnace. Detailed Implementation

[0016] like Figure 1 As shown, the linkage control system for emergency shutdown of a blast furnace provided by the present invention involves a blast furnace shutdown control module, a hot blast stove system, a blower system, a TRT system, a bag filter dust collector system, furnace top equipment, a ore and coke bin system, a pulverized coal injection system, and a water system.

[0017] During normal production, the blower system is the power source for the entire blast furnace air supply system, generating cold air which is then sent to the hot blast stove system. The hot blast stove system heats the cold air, turning it into hot air before sending it into the blast furnace body, providing a heat source and air pressure for blast furnace smelting.

[0018] The pulverized coal injection system injects pulverized coal into the blast furnace tuyeres as fuel supplement, working together with hot blast and coke to maintain the furnace temperature.

[0019] The ore and coke bin system is used for the batching and conveying of ore and coke, delivering the furnace charge to the furnace top equipment.

[0020] The furnace top equipment receives the furnace charge from the ore and coke bins and loads it into the blast furnace; at the same time, it collects the gas produced by the blast furnace and sends it downstream.

[0021] The TRT system utilizes the residual pressure and heat of blast furnace gas to generate electricity, and is connected in series on the blast furnace gas outlet pipeline.

[0022] The baghouse dust collection system removes dust and purifies blast furnace gas, and the purified gas is then sent to the pipeline network for recycling.

[0023] The water system provides cooling, sealing, and spraying water for the blast furnace body, hot blast stove, TRT, bag filter, and furnace top equipment.

[0024] In the event of an emergency shutdown, the blast furnace shutdown control module of this invention controls other systems in a coordinated manner. The specific control method is as follows: The feeding and energy supply to the furnace are cut off. The ore and coke bin system stops feeding and prohibits feeding. The pulverized coal injection system stops pulverizing and cuts off the pulverized coal gas supply. After receiving the command to stop feeding, the furnace top equipment locks the feeding gate valve, preventing the ore and coke bin from feeding into the furnace. The pulverized coal injection system is hard-interlocked with the blast furnace shutdown control module; once the shutdown command is issued, pulverized coal injection immediately terminates.

[0025] The blast furnace shutdown control module control cabinet cuts off the hot air and air supply paths. The hot blast stove system stops combustion, closes the hot blast valve, and initiates furnace shutdown. Here, the hot blast stove is shut down first, and the hot blast output is cut off. The blower system begins to reduce airflow to prevent hot blast backflow and furnace temperature runaway. The control cabinet stops gas recovery and residual pressure utilization. Here, the TRT system closes the stationary vanes, stops power generation, and cuts off the gas supply path. The bag filter dust collector gradually shuts down filtration in preparation for gas shut-off.

[0026] The TRT system must be shut down before gas supply is cut off to prevent equipment overspeed and damage. The bag filter system is linked to the TRT system; the bag filter can only enter the shutdown procedure after the TRT system is shut down.

[0027] Further, the safety control of the blast furnace top. When operating the top equipment, the steam is turned on, the top vent is opened, and the gas shut-off valve is closed. Here, the steam is turned on first, then the top vent is opened, and finally the gas shut-off valve is closed.

[0028] Furthermore, the main air source is shut down. Upon receiving the shutdown completion signal, the blower system vents all air and shuts down. For the water system, the cooling water volume is adjusted according to the shutdown progress to maintain cooling of critical equipment. While the water system does not participate in the timing changes, it provides cooling support for the hot blast stove, TRT, furnace top, and bag filter throughout the process.

[0029] It can be seen that the blast furnace shutdown control module in the system controls the emergency shutdown process. The hot blast stove system, blower system, TRT system, bag filter dust collector system, furnace top equipment, ore and coke bin system, pulverized coal injection system, and water system are parallel controlled subsystems. The following describes in detail the linkage control method for emergency shutdown of a blast furnace according to this application. Specific details, such as particular system structures and technologies, are presented for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application can also be implemented in other embodiments without these specific details.

[0030] It should be understood that, when used in this specification, the term "comprising" indicates the presence of the described feature, integral, step, operation, element, and / or component, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or collections thereof. The terms "comprising," "including," "having," and variations thereof all mean "including but not limited to," unless otherwise specifically emphasized.

[0031] The terms "one embodiment" or "some embodiments" used in this application mean that one or more embodiments of this application include the specific features, structures, or characteristics described in that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this application do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized.

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Please see Figure 2 The diagram shows a flowchart of a linkage control method for an emergency shutdown of a blast furnace in a specific embodiment. The method includes: S1: In response to the emergency shutdown command issued by the blast furnace foreman, the blast furnace shutdown control module synchronously sends emergency shutdown linkage signals to the hot blast stove system, bag filter system, blower system, TRT system, furnace top equipment, ore and coke bin system, water system and pulverized coal injection system, executes the operation of closing the oxygen-enriched shut-off valve, prohibiting the opening of the lower gas cylinder, prohibiting the feeding operation and closing the mixing air shut-off valve, and monitors the execution feedback status of the oxygen-enriched shut-off valve and the mixing air shut-off valve in real time.

[0034] In some embodiments, the blast furnace shutdown control module adopts a PLC module, which is connected to the touch screen instructions and emergency stop button on the control panel. If any signal is valid, it is determined that the emergency shutdown command is effective.

[0035] The blast furnace shutdown control module sends linkage signals to the hot blast stove system, bag filter system, blower system, TRT system, furnace top equipment, ore and coke bin system, water system, and pulverized coal injection system via the industrial Ethernet bus. The blast furnace shutdown control module outputs a disconnect signal through the DO port to the electromagnetic actuator of the oxygen-enriched shut-off valve, blocking the opening command of the lower sealing valve, terminating the feeding action of the charging belt and hopper via the ore and coke bin control system, and closing the mixing air shut-off valve via the drive circuit.

[0036] The blast furnace shutdown control module collects feedback signals from the valve position limit switches and potentiometers associated with the oxygen-enriched shut-off valve and the mixed air shut-off valve. When the feedback signal matches the command status, the action is deemed valid.

[0037] S2: After confirming that the execution feedback status of the mixing air shut-off valve is closed, the blast furnace shutdown control module determines the first target opening degree of the cold air release valve based on the current real-time monitored blast furnace hot blast pressure value and controls it to open to the first target opening degree. After controlling the pressure reducing valve group to switch to manual mode, it opens to the second preset opening degree and sends a command to the hot blast stove system to control the hot blast stove system to perform the shutdown combustion and furnace shut-off operations.

[0038] In some embodiments, the blast furnace shutdown control module continuously samples and confirms the position signal of the mixing air shut-off valve. The hot blast pressure acquisition point is selected on the straight section of the main hot blast pipe, away from bends and valve throttling positions, and a piezoresistive pressure transmitter is used to acquire real-time pressure values. A preset opening mapping table is used to determine the first target opening degree of the cold air vent valve based on the ratio of the current hot blast pressure to the normal operating pressure, and the opening degree command is output to the hydraulic actuator.

[0039] Furthermore, the blast furnace shutdown control module sends a manual mode switching command to the pressure reducing valve group, cutting off the original regulating circuit and directly outputting a control signal for the second preset opening degree. It also sends a shut-off command to the hot blast stove system, triggering the hot blast stove to close the combustion gas valve and combustion air valve, sealing the hot blast stove cavity, and stopping heat exchange.

[0040] When the mixing air shut-off valve is completely closed, the hot air system and the cold air system are completely isolated. At this time, opening the cold air vent valve can release pressure in a directional manner, preventing cold air backflow. Switching the pressure reducing valve group to manual mode cancels the original automatic adjustment mode. The hot blast stove shutdown operation can isolate the airflow between the blast furnace and the hot blast stove, preventing heat loss from the hot blast stove or gas from entering the blast furnace.

[0041] S3: The blast furnace shutdown control module continuously monitors the hot blast pressure value and the hot blast pressure drop rate of the blast furnace in real time, and determines whether the hot blast pressure value is lower than the first set pressure threshold and whether the hot blast pressure drop rate is within the preset safe rate range. If both conditions are met, proceed to step S4; If the condition is not met, adjust the opening of the cold air vent valve according to the current hot air pressure status.

[0042] S4: After confirming that the hot air pressure value is lower than the first set pressure threshold and the hot air pressure drop rate is within the preset safe rate range, control the pressure reducing valve group to perform a full opening operation, and control the cold air vent valve to gradually increase the opening degree according to the preset time interval gradient until the opening degree of the cold air vent valve reaches the third preset opening degree. During gradient adjustment, the preset time interval is adjusted based on the real-time monitoring value of the furnace top pressure.

[0043] In some embodiments, after receiving the jump signal, the blast furnace shutdown control module outputs a 100% opening command to the hydraulic drive mechanism of the pressure reducing valve group, and confirms that the pressure reducing valve group is fully open through valve position feedback.

[0044] Furthermore, the initial time interval for gradient adjustment is stored in the process parameter area, and the pressure value of the static pressure transmitter at the top of the furnace is acquired in real time. When the pressure at the top of the furnace is higher than the target range, the time interval is shortened to accelerate the opening speed of the cold air vent valve.

[0045] When the furnace top pressure is below the target range, the time interval is extended to slow down the opening rate. The time interval adjustment range is defined between 1s and 5s to prevent over-adjustment. The blast furnace shutdown control module continuously monitors the opening of the cold air vent valve and stops gradient adjustment when it reaches the third preset opening.

[0046] It can be seen that fully opening the pressure-reducing valve assembly can assist in rapid pressure relief at the furnace top, while gradually opening the cold air vent valve achieves stable pressure relief, avoiding pressure surges inside the furnace caused by sudden valve movements. The furnace top pressure directly reflects the gas balance state inside the furnace; high pressure indicates insufficient pressure relief speed, requiring faster valve action. Low pressure indicates excessively rapid pressure relief, requiring a slower valve action.

[0047] S5: When the opening degree of the cold air vent valve is detected to reach the third preset opening degree and the pressure inside the blast furnace drops below the second set pressure threshold, the top steam valve is opened. After confirming that the execution feedback state of the top steam valve is in the open position, the top vent valve is opened to the fully open position.

[0048] S6: After confirming that the execution feedback status of the furnace top vent valve is in the open position, control the gas shut-off valve to perform the closing operation, and monitor the gas pressure value downstream of the gas shut-off valve in real time to verify the gas passage shut-off effect.

[0049] S7: After confirming that the gas shut-off valve is closed and the gas pressure downstream of the gas shut-off valve has dropped to the preset safe pressure range, control the cold air release valve to open to the fully open position, send a shutdown command to the blower system, and start the nitrogen purging operation at the furnace top to complete the emergency shutdown process of the blast furnace.

[0050] In some embodiments, after confirming that the gas cutoff is effective, the blast furnace shutdown control module outputs a full-open command to the cold air release valve, and confirms that the valve position is in place through feedback.

[0051] The blast furnace shutdown control module sends a shutdown command to the blower system, triggering the blower to stop. The nitrogen purging circuit at the furnace top is activated to continuously purge and replace residual gas in the furnace. The blast furnace shutdown control module summarizes all valve position statuses, pressure parameters, and purging statuses; once all parameters are met, it outputs a shutdown completion signal.

[0052] In one embodiment of the present invention, such as Figure 3 As shown, based on step S3, continuously and in real-time monitoring of the hot blast pressure value and the hot blast pressure drop rate of the blast furnace, it is determined whether the hot blast pressure value is lower than the first set pressure threshold and whether the hot blast pressure drop rate is within the preset safe rate range; if both conditions are met simultaneously, then proceed to step S4, which specifically includes the following steps: S31: Pre-construct a safe rate function with the current hot air pressure value as the independent variable, generate an upper limit curve and a lower limit curve of the rate of decrease that dynamically shrink as the pressure decreases, and define the area between the two curves as the safe rate envelope interval under the current operating conditions.

[0053] Specifically, the steps include the following: S311: The blast furnace shutdown control module collects historical operating data within a set time period before the shutdown command is triggered. It extracts the characteristic values ​​of the furnace belly gas volume, the pressure difference of the material column, and the permeability index from the data. The three characteristic values ​​are calculated by a weighted fusion algorithm to obtain a basic resistance coefficient that characterizes the current furnace condition. The basic resistance coefficient is used as the benchmark parameter for constructing the safe rate envelope interval.

[0054] In some embodiments, the data collected by the blast furnace shutdown control module includes the furnace belly gas volume Q value, the cold air flow rate F measured by the cold air flow meter, the pressure Phot measured by the hot air pressure transmitter, and the pressure Ptop measured by the furnace top pressure transmitter.

[0055] Furthermore, the pressure difference of the material column ΔP = Phot - Ptop at each sampling time is calculated, and the air permeability index K = F / ΔP at each sampling time is then calculated.

[0056] Furthermore, the furnace gas volume Q, the pressure difference ΔP of the feed column, and the permeability index K are normalized to eliminate dimensional differences before being input into the weighted fusion unit.

[0057] Furthermore, the weighted fusion unit has three preset weighting coefficients α, β, and γ, which correspond to the contributions of Q, ΔP, and K, respectively, with α + β + γ = 1. The fusion unit outputs Rbase = αQnorm + βΔPnorm + γ*Knorm, where Rbase is the basic resistance coefficient characterizing the current furnace condition, with a value ranging from 0.5 to 2.0. A larger value indicates poorer permeability of the material column and greater resistance.

[0058] S312: Construct a dynamic envelope model with hot air pressure value as independent variable. The dynamic envelope model adopts a piecewise function form. The first segment is a high-pressure straight segment with pressure above the critical value. The envelope boundary maintains a constant width. The second stage is a low-pressure contraction section where the pressure is lower than the critical value, and the envelope boundary undergoes non-linear contraction according to the product relationship between the basic resistance coefficient and the pressure value; two adjustable parameters are preset in the dynamic envelope model, namely the critical value of the starting pressure of contraction and the contraction rate coefficient.

[0059] In some embodiments, the function form of the high-pressure straight section is: Vmax = Vbase + Doffset, Vmin = Vbase - Doffset.

[0060] Where Vbase is the reference rate, taking values from 3 kPa / min to 5 kPa / min, and Doffset is the fixed half-width, taking values from 1 kPa / min to 2 kPa / min. Both are configurable constants.

[0061] Furthermore, the function form of the low-pressure contraction section is: Vmax(P) = Vbase * (P / Pcrit)^(Rbase * λ), Vmin(P) = the negative form of Vbase * (P / Pcrit)^(Rbase * λ).

[0062] Where Pcrit is the critical value of the starting pressure of contraction, with a value range of 80 kPa to 120 kPa, λ is the contraction rate coefficient, with a value range of 0.3 to 0.7, and Rbase is the basic resistance coefficient calculated in step S311.

[0063] Furthermore, the high-pressure straight section and the low-pressure contraction section are spliced at P = Pcrit to ensure the continuity of the function.

[0064] When P ≥ Pcrit, Vmax and Vmin take fixed values; when P < Pcrit, Vmax and Vmin contract according to the power function law as P decreases, and the speed of contraction is determined by the product of Rbase * λ.

[0065] It can be seen that when the pressure in the blast furnace burden column is higher than the critical value, the supporting force of the gas on the burden layer is strong enough, the burden layer structure is stable, and the allowable pressure change rate can be maintained constant. When the pressure drops below the critical value, the gas supporting force weakens, the burden layer begins to enter a stable state, and the allowable rate decreases as the pressure decreases. By defining Rbase, the contraction law is linked to the specific furnace conditions. Even if the pressure is the same in different furnace runs, the allowable rate range is different, achieving personalized customization of the control strategy.

[0066] S313: Define a burden layer porosity compensation factor in the low-pressure contraction section. The burden layer porosity compensation factor is calculated in real time according to the detection signal of the top burden line depth; Multiply the compensation factor by the basic resistance coefficient to obtain the corrected dynamic contraction coefficient, and replace the original contraction rate coefficient with the dynamic contraction coefficient to achieve adaptive adjustment of the speed of contraction of the envelope boundary.

[0067] In some embodiments, the blast furnace shutdown control module establishes a data channel with the furnace top material line detection system to acquire the material line depth value Ldepth measured by the mechanical probe or radar level gauge in real time.

[0068] Define a material layer porosity compensation function, in the form δ=1+μ*(Lref-Ldepth) / Lref, Where Lref is the reference material line depth, ranging from 1.5 meters to 2.0 meters, and μ is the compensation strength coefficient, ranging from 0.1 to 0.3.

[0069] Furthermore, when the actual material depth Ldepth is deeper than Lref, Lref-Ldepth is negative and δ is less than 1; when the actual material depth Ldepth is shallower than Lref, Lref-Ldepth is positive and δ is greater than 1.

[0070] Further, the basic resistance coefficient Rbase calculated in step S311 is multiplied by the compensation factor δ to obtain the corrected dynamic contraction coefficient Radj=Rbase*δ.

[0071] Furthermore, substitute Radj into the low-pressure contraction segment function in step S312 to replace the original Rbase, i.e., Vmax(P)=Vbase*(P / Pcrit)^(Radj*λ).

[0072] It can be seen that the depth of the feed line reflects the size of the space above the material layer in the furnace. The deeper the feed line, the more space is available above, the weaker the support above the material layer, the lower the overall stability of the feed column, and the more sensitive it is to pressure changes, requiring rate limiting.

[0073] The compensation factor δ adjusts the shrinkage coefficient in real time based on the material depth. The deeper the material, the smaller δ becomes, leading to a decrease in Radj and a smaller shrinkage exponent, resulting in slower shrinkage. Therefore, Radj needs to be corrected. The smaller the exponent Radj*λ, the larger the power function value, which in turn increases the allowable rate. Thus, the compensation factor should be designed as δ = 1 - μ*(Lref - Ldepth) / Lref, so that δ > 1 at deeper material depths, increasing Radj and accelerating shrinkage. In practical engineering, the function direction needs to be calibrated according to the physical mechanism.

[0074] S314: Determine the range of the hot air pressure value based on the current real-time monitored hot air pressure value; If the pressure is higher than the critical value, the high-pressure flat segment function is called to calculate the upper and lower limits of the allowable rate of descent. If the pressure is below the critical value, the low-pressure contraction segment function, which has been corrected by the compensation factor, is called to calculate the upper and lower limits of the allowable rate of descent that dynamically tightens as the pressure decreases. The area between the two curves is the safe rate envelope interval under the current operating conditions.

[0075] In some embodiments, within each cycle, the real-time pressure value Pcur output by the current hot air pressure transmitter is read and compared with the pressure critical value Pcrit set in step S312.

[0076] If Pcur ≥ Pcrit, the high-pressure flat section function is called, and Vmaxfixed and Vminfixed are read from the configuration parameters as the output.

[0077] If Pcur < Pcrit, the low-pressure contraction section function is called, and Pcur, Vbase, Pcrit, Radj, and λ are substituted into the power function expression to calculate Vmax(Pcur) and Vmin(Pcur).

[0078] Furthermore, the pair of calculated values is saved as the upper and lower limits of the allowable descent rate for the current cycle. These two values serve as the boundaries of the dynamic safety envelope interval for real-time rate compliance judgment. In this way, the piecewise judgment can automatically select the correct function form according to the pressure range, ensuring the calculation accuracy within the entire pressure range.

[0079] S32: The blast furnace shutdown control module continuously collects hot air pressure values, stores each collected pressure value in a circular buffer in chronological order to form a real-time pressure trend sequence of length N; based on the pressure difference between two adjacent sampling points and the sampling period in the real-time pressure trend sequence, the instantaneous descent rate at each sampling moment is calculated.

[0080] In some embodiments, a circular buffer with a length of L is configured, where L ranges from 10 to 20. The newly sampled pressure value is written to the head of the buffer, and at the same time, the oldest data at the tail of the buffer is removed, so that the buffer always maintains a continuous pressure value sequence [P1, P2,..., PL] of the most recent L cycles.

[0081] Traverse this sequence, calculate the difference ΔPi = Pi - P(i + 1) between adjacent sampling points, divide the difference by the sampling period T to obtain the instantaneous descent rate Vi for each time period, and take the weighted moving average of the nearest three instantaneous rates as the output value Vcur of the current instantaneous descent rate to filter out high-frequency noise interference from the sensor.

[0082] S33: The blast furnace shutdown control module constructs a two-dimensional state space coordinate system with the current hot air pressure value as the abscissa and the current instantaneous descent rate as the ordinate; maps the pressure value and the instantaneous descent rate at the current sampling moment to a discrete point in the state space, and connects the discrete points of consecutive multiple sampling cycles in history to form a state trajectory curve.

[0083] Specifically, it includes the following steps: S331: The blast furnace shutdown control module calculates the dynamic scaling factor of the pressure axis and the dynamic scaling factor of the rate axis in real time based on the historical fluctuation range of the current hot blast pressure value. It then divides the collected original hot blast pressure value and instantaneous drop rate value by the corresponding scaling factor and maps them to a dimensionless standardized coordinate system.

[0084] In some embodiments, a circular history array is configured to store the original pressure value Praw[i] and the original rate value Vraw[i] of the past M sampling periods, respectively, where M is 30 to 50.

[0085] Furthermore, in each sampling period, the maximum value Pmax and the minimum value Pmin in the historical pressure array are found, and the pressure fluctuation amplitude ΔP = Pmax - Pmin is calculated.

[0086] If ΔP is less than the preset threshold Pth, the pressure scaling factor SP takes a fixed value Pfix; otherwise, SP takes the difference between the current pressure value Pcur and Pmin, divided by ΔP, and then multiplied by a base coefficient. The expression is SP=((Pcur-Pmin) / ΔP)*Pbase, where Pbase takes a value of 100kPa.

[0087] Furthermore, for the rate axis, the maximum absolute value Vabsmax of the historical rate array is calculated. If Vabsmax is less than the preset threshold Vth, the rate scaling factor SV is set to a fixed value Vfix; otherwise, SV is the ratio of the current absolute rate to Vabsmax multiplied by Vbase, expressed as SV=(|Vcur| / Vabsmax)*Vbase, where Vbase is set to 5kPa / min.

[0088] Furthermore, Pcur is divided by SP to obtain the dimensionless pressure coordinate X, and Vcur is divided by SV to obtain the dimensionless velocity coordinate Y. The (X,Y) coordinates are then output to the trajectory buffer.

[0089] It can be seen that the hot air pressure and descent rate have different dimensions and significantly different numerical ranges. Plotting them directly on the same coordinate system would result in one axis being compressed and the other stretched, distorting the trajectory shape. By using a dynamic scaling factor to map the original values ​​to a similar numerical range, the influence of dimensions can be eliminated, making pressure and rate changes geometrically comparable. The scaling factor adaptively adjusts based on historical fluctuation ranges, ensuring that the coordinate axes automatically expand when pressure or rate changes drastically and automatically contract when changes are gradual, always placing the current working point near the center of the visible area of ​​the coordinate system.

[0090] S332: Construct a circular trajectory buffer, store N consecutive standardized coordinate points in the order of sampling time, each coordinate point contains dimensionless pressure and dimensionless velocity values; calculate the Euclidean distance and orientation angle between two adjacent points in the buffer in real time, and generate displacement vector sequence and orientation angle sequence.

[0091] In some embodiments, two floating-point numbers are defined to represent the dimensionless pressure coordinate X and the dimensionless velocity coordinate Y, respectively.

[0092] Furthermore, in each sampling period, the (X,Y) output from step S331 is written to the head of the buffer, and the oldest data at the tail of the buffer is discarded. The buffer maintains a write pointer and a read pointer; the write pointer points to the position of the latest data, and the read pointer is used to traverse historical data.

[0093] Furthermore, in each cycle, all adjacent point pairs in the buffer are traversed, starting from the oldest point and ending at the newest point. The Euclidean distance and orientation angle between each pair of points are calculated. The average orientation angle θavg and the change in orientation angle Δθ=|θcur-θpre| of the three most recent displacement vectors are also calculated to determine the turning trend of the trajectory.

[0094] It can be seen that the displacement vector between adjacent points characterizes the direction and step size of the trajectory's movement over a short period. The Euclidean distance reflects the drastic nature of the state change, while the orientation angle reflects the dominant trend of the state change. By continuously tracking the displacement vector, the dynamic evolution of the pressure-rate combined state can be captured. The magnitude of the orientation angle change Δθ directly indicates whether the trajectory has bent; Δθ close to 0 indicates that the trajectory is moving along a straight line, while a larger Δθ indicates that the trajectory is turning, corresponding to a sudden change in the rate of pressure decrease or a change in the trend of pressure decrease.

[0095] S333: Process the sequence of coordinate points in the trajectory buffer, set the window length L, calculate the least squares fitted quadratic curve of the coordinate points in the current window in each sampling period, calculate the curvature value at the center point of the window, and record the rate of change of curvature over time.

[0096] In some embodiments, the most recent L consecutive coordinate points are extracted from the trajectory buffer in each sampling period to form a point set ((X(k-L+1), Y(k-L+1)), ..., (Xk, Yk)), where k is the current sampling number.

[0097] Furthermore, the least squares method is used to fit the quadratic curve form Y=aX at these points. 2 +bX+c, the coefficients a, b, and c are obtained by solving the normal system of equations.

[0098] Specifically, construct matrix A and vector B, and the behavior of A is [Xi]. 2Composed of [Xi,1], where B is the corresponding Yi, solve (A TA inverse multiplied by A TB The coefficients are obtained.

[0099] According to the curvature formula Calculate the curvature value κcur at the center point Xcenter of the window, where Xcenter is the average of the X coordinates of all points within the window.

[0100] Obtain the curvature values ​​κprev2, κprev1, and κcur of the three most recent windows, and calculate the rate of change of curvature Δκ = (κcur - κprev1) / T, where T is the sampling period. Output the curvature κcur and the rate of change of curvature Δκ of the current window to the trajectory classifier.

[0101] It should be noted that in the pressure-rate state space, different furnace conditions correspond to different trajectory shapes: during a steady pressure decrease, the trajectory is approximately a straight line with a curvature close to 0. When the rate suddenly increases (pressure decreases rapidly), the trajectory bends downwards with a positive curvature; when the rate decreases, the trajectory bends upwards with a negative curvature. The rate of change of curvature reflects the speed at which the degree of curvature changes, and can provide early warning that the trajectory is about to deviate from the safe zone.

[0102] S334: Input the curvature value and curvature change rate of the current window into a pre-trained trajectory classifier. The classifier outputs the matching degree between the current trajectory and the preset smooth depressurization standard trajectory template. The matching degree, current state point coordinates, and trajectory buffer data are packaged and used as input parameters for step S34.

[0103] In some embodiments, the classifier employs a lightweight Gaussian mixture model, and template parameters for three typical operating conditions are obtained in advance through offline training: a steady-state pressure reduction template G1, a fast-rate template G2, and a slow-rate template G3.

[0104] Furthermore, each template is based on two Gaussian distributions, corresponding to the mean and variance of curvature κ and the rate of change of curvature Δκ, respectively.

[0105] In each sampling period, the (κcur,Δκ) output from step S333 is input into the classifier to calculate the probability P1, P2, P3 that the point belongs to each template.

[0106] Furthermore, the probability calculation formula is Pj=πj*N(κcur,Δκ|μj,Σj) / sum(πi*N(...)), where πj is the prior probability of the template, and μj and Σj are the mean vector and covariance matrix of the template.

[0107] Furthermore, the classifier outputs P1 as the matching degree between the current trajectory and the steady pressure reduction template, and stores P1, P2, P3, and the corresponding maximum probability. The matching degree P1, the coordinates (X, Y) of the current state point, the coordinates of the nearest 5 points, and the curvature κcur of the current window are packed into a dataset as the input parameter during the execution of step S34.

[0108] Furthermore, the prior probability πj reflects the frequency of occurrence of various working conditions in historical data, enabling the classifier to balance the weights of different categories. When the matching degree P1 is higher than the threshold, it indicates that the current trajectory coincides with the steady pressure reduction mode, and the system can trust the current process. When P1 is low while P2 or P3 is high, it indicates that the trajectory is deviating from the safe mode and requires early intervention.

[0109] S34: The blast furnace shutdown control module divides the state space into multiple regions: the first region is where the pressure is higher than the first set pressure threshold and the rate is within the envelope interval, the second region is where the pressure is higher than the first set pressure threshold but the rate exceeds the envelope interval, the third region is where the pressure is lower than the first set pressure threshold and the rate is within the envelope interval, and the fourth region is where the pressure is lower than the first set pressure threshold but the rate exceeds the envelope interval; different branch processing logics are executed according to the region number where the current discrete point is located.

[0110] In some embodiments, the blast furnace shutdown control module pre-defines the dividing lines of the four logical regions in the state space: The first set pressure threshold Pset1 serves as the horizontal dividing line, dividing the space into a high-pressure area (P > Pset1) and a low-pressure area (P ≤ Pset1); Furthermore, the dynamic safety rate envelope interval generated in step S31 serves as the vertical dividing line, dividing the space into a rate compliance area (Vmin ≤ V ≤ Vmax) and a rate overlimit area (V < Vmin or V > Vmax).

[0111] Furthermore, the two dividing lines divide the state space into four quadrant regions: Region I is the high-pressure compliance area, Region II is the high-pressure overlimit area, Region III is the low-pressure compliance area, and Region IV is the low-pressure overlimit area.

[0112] Furthermore, the coordinates (Pcur, Vcur) of the current state point Scur are compared with the above boundaries to determine the region number it belongs to; If the state points of three consecutive sampling periods all fall into the same region, it is confirmed that the state of this region is stable, and the corresponding branch processing logic is executed.

[0113] It can be seen that the dynamic process of the blast furnace is simplified into four standard working condition regions, and each region corresponds to a different physical state in the furnace: Region I represents stable pressure reduction under high pressure and belongs to the normal process; Zone II indicates that the high pressure is decreasing too quickly or too slowly, requiring intervention. Zone III indicates that the pressure has dropped to the target value and the rate is safe, and conditions are met to proceed to the next stage; Zone IV indicates that the pressure has dropped to the target value, but the rate is still unsafe and requires further adjustment. The triple confirmation mechanism avoids false triggering caused by fluctuations in a single sampling.

[0114] S35: When the status point falls into the third area, generate a release command to proceed to step S4; When the state point falls into the second or fourth region, the target opening correction amount of the cold air vent valve is calculated based on the deviation of the current pressure value and rate, and the valve fine-tuning command is output. When the status point falls into the first region, maintain the current valve opening and continue monitoring.

[0115] Specifically, the steps include the following: S351: Receive output area identifier and current instantaneous descent rate Vcur, current safe envelope interval boundary values ​​Vmin and Vmax; When the region is identified as the second or fourth region, calculate the static deviation ΔV = Vcur - (Vmin + Vmax) / 2, and calculate the dynamic trend deviation ΔVtrend = (Vcur - Vpre) / T - dVref, where Vpre is the instantaneous descent rate of the previous sampling period, T is the sampling period, and dVref is the preset expected rate of change. Multiply the static deviation and dynamic trend deviation by the weighting coefficients α and β respectively, and then sum them to obtain the comprehensive deviation ΔVco = α·ΔV + β·ΔVtrend.

[0116] In some embodiments, the blast furnace shutdown control module receives a region identification signal, which is an enumeration type and takes only region II or region IV values. It also receives the current rate value Vcur and the previous cycle rate value Vpre from step S32, as well as the upper and lower boundary values ​​Vmin and Vmax from the safety rate envelope interval generator in step S31.

[0117] Furthermore, by executing the formula ΔV=Vcur-(Vmin+Vmax) / 2, the degree to which the current rate deviates from the center line of the envelope is obtained, with the dimension being kPa / min.

[0118] Further, calculate the rate of change (Vcur-Vpre) / T, and then subtract the preset expected rate of change dVref, where dVref is preset as a segmented constant according to the ideal change law of the blast furnace at different pressure stages. For example, it is taken as -0.2kPa / min² in the high pressure section, which means that the rate is allowed to increase slightly, and it is taken as 0 in the low pressure section, which means that the rate is expected to remain constant.

[0119] Further, they are respectively sent to a weighted summing unit. The weighting coefficients α and β are stored in non-volatile registers, where α ranges from 0.6 to 0.8, β ranges from 0.2 to 0.4, and α + β = 1.

[0120] Further, the weighted summing unit outputs a comprehensive deviation ΔVco, which can be positive or negative. A positive value indicates that the rate is too fast and the valve opening needs to be reduced, while a negative value indicates that the rate is too slow and the valve opening needs to be increased.

[0121] It can be seen that the static deviation reflects the position deviation of the current rate relative to the center line of the safety envelope, indicating whether the rate is too fast or too slow. The dynamic trend deviation captures the change trend of the rate itself. If the rate is accelerating away from the center line, even if the current deviation is small, the adjustment force needs to be increased in advance.

[0122] Further, the two are weighted and fused, so that the adjustment instruction is not only based on the current deviation, but also takes into account the future evolution direction of the deviation, which is equivalent to defining a differential feedforward effect, but is different from the differential term in the standard PID because it is based on a preset ideal rate of change rather than zero.

[0123] This design is derived from the physical law that the rate change should follow during the blast furnace pressure reduction process: the rate is allowed to gradually increase in the high-pressure stage and should tend to be stable in the low-pressure stage. Therefore, the desired rate of change is not constantly zero. It is applicable to occasions such as the blast furnace being on standby, which requires fast response and stability, and reduces the possibility of rate overshoot.

[0124] S352: Obtain the current hot air pressure value Pcur; configure three pressure intervals and their corresponding basic gain coefficients Kpbase1, Kpbase2, Kpbase3, and a rate correction coefficient γ; Select the corresponding basic gain Kpbase according to the interval where Pcur is located, and then calculate the gain correction factor δ = 1 + γ·|Vcur| / Vmax according to the current instantaneous descent rate Vcur. Multiply the basic gain by the correction factor to obtain the adaptive gain Kp = Kpbase·δ.

[0125] In some embodiments, configure a pressure interval mapping table, indexed by the hot air pressure value Pcur, and divide the pressure range into three consecutive intervals: the high-pressure interval [PH1, PH2] corresponds to the basic gain Kpbase1, the medium-pressure interval [PM1, PM2] corresponds to Kpbase2, and the low-pressure interval [PL1, PL2] corresponds to Kpbase3.

[0126] Further, the interval boundary values are pre-tuned according to the blast furnace design parameters. For example, PH1 is taken as 200 kPa, PH2 is taken as 300 kPa, and Kpbase1 is taken as 0.8% / kPa·min -¹, Kpbase2 takes 1.2% / kPa·min - ¹, Kpbase3 is taken as 1.8% / kPa·min - ¹.

[0127] Furthermore, Pcur is read in real time, the interval is determined by comparison, and the corresponding basic gain Kpbase is output.

[0128] Furthermore, the current instantaneous descent rate Vcur and the current safe envelope upper limit Vmax are received, and the correction factor δ=1+γ·|Vcur| / Vmax is calculated, where γ is a preset coefficient with a value of 0.1 to 0.3, used to control the degree of rate enhancement on gain.

[0129] Furthermore, Kpbase is multiplied by δ to obtain the adaptive gain Kp. Kp is then limited to the range [Kpmin, Kpmax] to prevent the gain from being too large or too small under abnormal conditions.

[0130] S353: Receive the comprehensive deviation ΔVco and adaptive gain Kp, calculate the original correction amount ΔOpe=Kp·ΔVco; read the current opening degree Opencur of the cold air vent valve, and obtain the preset single-step maximum allowable adjustment amount ΔOpenmax and valve opening limit value [Openmin,Openmax]; Limit the amplitude of ΔOpe. If |ΔOpe|>ΔOpenmax, then let ΔOpenlimited=sign(ΔOpe)·ΔOpenmax; otherwise, ΔOpenlimited=ΔOpe. Calculate the target opening degree Opentarget = Opencur + ΔOpenlimited, and limit it within the range of [Openmin, Openmax]. Output Opentarget to the cold air vent valve actuator.

[0131] In some embodiments, a multiplier is defined to receive the comprehensive deviation ΔVco from step S351 and the adaptive gain Kp from step S352, and performs the multiplication operation ΔOpe=Kp·ΔVco to obtain the original opening correction amount.

[0132] Define a single-step limiter with a maximum allowable adjustment ΔOpenmax per step. This value is set according to the mechanical characteristics and safety requirements of the cold air vent valve, such as 2% to 5%.

[0133] Furthermore, the limiter compares |ΔOpe| with ΔOpenmax. If the former is greater than the latter, then ΔOpenlimited = sign(ΔOpe)·ΔOpenmax; otherwise, ΔOpenlimited = ΔOpe.

[0134] Furthermore, an opening calculation and clamping device is defined to read the current valve opening feedback value Opencur (from the valve position transmitter), calculate the target opening Opentarget = Opencur + ΔOpenlimited, and compare Opentarget with the preset valve opening limit values ​​[Openmin, Openmax]. If Opentarget is less than Openmin, Openmin is used; if it is greater than Openmax, Openmax is used; otherwise, it remains unchanged. Finally, Opentarget is output to the valve's analog output channel to drive the actuator.

[0135] As can be seen, the multiplier performs basic proportional control calculations, mapping the overall deviation to the valve opening adjustment. The single-step limiter prevents excessive valve movement caused by excessive single adjustment, which could lead to pressure fluctuations or mechanical shocks.

[0136] The valve opening clamp ensures that the target opening degree is always within the valve's permissible physical range, preventing the valve from jamming or becoming uncontrollable due to exceeding the upper or lower limit. This embodiment constitutes a closed-loop regulation output link with physical constraints, ensuring that control commands are executed only after a safety check based on theoretical calculations, thus maintaining the control system's performance adjustment within safe boundaries.

[0137] In one embodiment of the present invention, based on step S5, the following is a possible embodiment and its specific implementation will be described in a non-limiting manner. S5 specifically includes the following steps: S51: The blast furnace shutdown control module collects the feedback signal of the cold air venting valve opening and the real-time value of the blast furnace pressure in real time, and performs dual parameter value comparison with the third preset opening and the second set pressure threshold respectively.

[0138] In some embodiments, the analog signal output by the potentiometer-type valve position sensor of the cold air vent valve is read, the signal is converted into a percentage of the actual opening degree Ofan of the cold air vent valve, and the value is compared with the preset third preset opening degree Oset3.

[0139] Furthermore, the pressure comparison channel acquires the 4-20mA current signal output by the furnace pressure transmitter through the analog input module, converts it into the measured value of the furnace pressure Pfurn, and compares it with the second set pressure threshold Pset2.

[0140] Furthermore, a ready signal is output through a logical AND operation; the operation formula is as follows: .

[0141] S52: After confirming that the opening degree of the cold air vent valve meets the standard and the pressure inside the furnace meets the standard, output the start drive signal.

[0142] S53: Continuously collect the real-time opening degree of the steam valve on the furnace top and determine whether the steam valve has reached the 100% fully open position.

[0143] In some embodiments, a continuous period determination rule is implemented, and the steam valve is determined to be fully open only when the Osteam value is equal to 100% for five consecutive sampling periods. The determination formula is as follows:

[0144] Steam ready This is the steam curtain ready signal. A true output indicates that all five valves are fully open and the steam protection system is established. A false output indicates that at least one valve is not fully open and the system is not ready.

[0145] i=1,2,...,5 represents the steam valve numbers at different locations on the top of the blast furnace.

[0146] O steam,i This represents the real-time opening feedback value of the i-th steam valve. 100% is the fully open threshold. The blast furnace top diameter is large; if only some steam valves are opened, dead zones may form in the furnace top space. Air may be drawn into these dead zones, potentially causing an explosion, or localized high temperatures may damage the equipment. This embodiment requires all branch pipes to reach the fully open state simultaneously before the system considers the protective curtain to be formed. That is, the logical judgment rule is: a high-level ready signal is output only when the opening feedback values ​​of all steam branch pipe valves reach the fully open setting value. If the opening of any one or more valves does not reach the fully open setting value, a low-level signal is output, indicating that the steam protective curtain has not been established, and the execution of subsequent vent valve opening commands is prohibited.

[0147] S54: After confirming that the steam valve is fully open, perform electrical locking of the steam valve drive circuit and collect the pressure of the steam pipeline at the top of the furnace to determine if the pressure meets the standard.

[0148] In some embodiments, after outputting the ready signal, the manual intervention channel of the steam valve drive circuit is cut off to complete the electrical locking. The measured pressure Psteamline of the furnace top steam pipeline pressure transmitter is read and compared with the preset minimum steam operating pressure Psteammin. When Psteamline≥Psteammin, the steam pressure compliance signal Steampressok is output.

[0149] S55: After the circuit is locked and the steam pipeline pressure reaches the target, output a full-open command to control the furnace top vent valve to operate to the full-open position.

[0150] In some embodiments, upon simultaneously receiving a loop lock signal and a Steampressok signal, a full-open control command is output to the hydraulic drive mechanism of the furnace top vent valve. The hydraulic drive mechanism actuates the valve plate, and the valve position sensor provides real-time feedback on the position until the furnace top vent valve opening reaches 100%. This ensures the irreversible sequence of steam opening before venting, avoiding the safety hazard of the vent valve opening before the steam.

[0151] In one embodiment of the present invention, based on S4, adjusting the preset time interval according to the real-time monitoring value of the furnace top pressure during the gradient adjustment process specifically includes the following steps: S41: The blast furnace shutdown control module collects the measured value of the furnace top pressure in real time and performs noise reduction processing on the collected pressure data.

[0152] S42: Retrieve historical and real-time data from the pressure timing buffer, calculate the furnace top pressure deviation and pressure change rate, divide the adjustment interval based on the quantified values ​​of the deviation and change rate, and determine the time interval adjustment direction and basic adjustment amount.

[0153] In some embodiments, the pressure value Ptopfiltered after noise reduction is extracted from the preset target pressure value Ptoptarget at the top of the furnace, and the pressure deviation at the top of the furnace is calculated as ΔP = Ptopfiltered - Ptoptarget. A positive deviation indicates that the pressure at the top of the furnace is higher than the target value, and a negative deviation indicates that it is lower than the target value.

[0154] Extract the filtered pressure values ​​Ptopfiltered(n) and Ptopfiltered(n-1) from the two most recent sampling periods, and calculate the furnace top pressure change rate vtop=[Ptopfiltered(n)-Ptopfiltered(n-1)] / Ts.

[0155] The combination of ΔP and vtop is divided into three adjustment intervals: interval 1 (ΔP>0 and vtop>0), interval 2 (|ΔP|≤0.5kPa and |vtop|≤0.2kPa / s), and interval 3 (ΔP<0 and vtop<0), corresponding to the adjustment directions of decreasing, maintaining, and increasing the time interval, respectively. The basic adjustment amount ΔT is set to 0.5 seconds, 0 seconds, and 0.5 seconds according to the interval.

[0156] Furthermore, the pressure deviation at the top of the furnace reflects the degree of deviation between the current pressure inside the furnace and the target state, while the pressure change rate reflects the deviation trend. Combining the two can accurately determine the dynamic change trend of the pressure inside the furnace. Different trends correspond to different time intervals for adjustment, ensuring that the adjustment logic fits the actual furnace condition.

[0157] S43: Based on the adjustment direction and the basic adjustment amount, calculate the time interval after real-time adjustment, lock the adjustment parameters, and apply them to the gradient opening adjustment of the cold air vent valve.

[0158] In some embodiments, based on the adjustment direction and basic adjustment amount determined in S42, and combined with the preset upper and lower limits of the time interval, the time interval after real-time adjustment, Tadjust=Tprev+ΔT, is calculated, where Tprev is the time interval of the previous gradient adjustment cycle, and ΔT is the basic adjustment amount.

[0159] Optionally, interval 1 is -0.5 seconds, interval 2 is 0 seconds, and interval 3 is +0.5 seconds.

[0160] Furthermore, when the calculated Tadjust exceeds the upper or lower limit range, it is clamped to the corresponding upper or lower limit value. After adjustment, Tadjust is locked and written into the gradient adjustment timing parameter table as the time interval for adjusting the cold air vent valve opening in the next cycle. The time interval clamping mechanism avoids process abnormalities caused by extreme adjustments and improves the stability of the adjustment.

[0161] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0162] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A linkage control method for emergency shutdown of a blast furnace, characterized in that, The methods include: S1: In response to the emergency shutdown command issued by the blast furnace foreman, send an emergency shutdown linkage signal, execute the operation of closing the oxygen-enriched shut-off valve, prohibiting the opening of the lower pressure valve, prohibiting the charging operation, and closing the mixing air shut-off valve, and monitor the execution feedback status of the oxygen-enriched shut-off valve and the mixing air shut-off valve in real time. S2: After confirming that the execution feedback status of the mixed air shut-off valve is closed, the blast furnace shutdown control module determines the first target opening degree of the cold air release valve based on the current real-time monitored blast furnace hot blast pressure value and controls it to open to the first target opening degree. After controlling the pressure reducing valve group to switch to manual mode, it opens to the second preset opening degree and sends a command to the hot blast stove system to control the hot blast stove system to perform the shutdown combustion and furnace shut-off operation. S3: Continuously monitor the hot blast pressure value and hot blast pressure drop rate of the blast furnace in real time, and determine whether the hot blast pressure value is lower than the first set pressure threshold and whether the hot blast pressure drop rate is within the preset safe rate range; if both conditions are met at the same time, proceed to step S4. S4: After confirming that the hot air pressure value is lower than the first set pressure threshold and the hot air pressure drop rate is within the preset safe rate range, control the pressure reducing valve group to perform a full opening operation, and control the cold air vent valve to gradually increase the opening degree according to the preset time interval gradient until the opening degree of the cold air vent valve reaches the third preset opening degree. S5: When the opening degree of the cold air vent valve is detected to reach the third preset opening degree and the pressure inside the blast furnace drops below the second set pressure threshold, the top steam valve is opened. After confirming that the execution feedback state of the top steam valve is in the fully opened position, the top vent valve is opened to the fully open position. S6: After confirming that the execution feedback status of the furnace top vent valve is in the open position, control the gas shut-off valve to perform the closing operation and monitor the gas pressure value downstream of the gas shut-off valve in real time. S7: After confirming that the gas shut-off valve is closed and the gas pressure downstream of the gas shut-off valve has dropped to the preset safe pressure range, control the cold air release valve to open to the fully open position, send a shutdown command to the blower system, and start the nitrogen purging operation at the furnace top to complete the emergency shutdown process of the blast furnace.

2. The linkage control method for emergency shutdown of a blast furnace according to claim 1, characterized in that, S3 specifically includes the following steps: S31: Pre-construct a safe rate function with the current hot air pressure value as the independent variable, generate an upper limit curve and a lower limit curve of the rate of descent that dynamically shrinks as the pressure decreases, and define the area between the two curves as the safe rate envelope interval under the current operating conditions. S32: The blast furnace shutdown control module continuously collects hot blast pressure values ​​and stores each collected pressure value in a ring buffer according to the time sequence, forming a real-time pressure trend sequence of length N. Based on the pressure difference and sampling period between two adjacent sampling points in the real-time pressure trend sequence, the instantaneous rate of decrease at each sampling moment is calculated. S33: Construct a two-dimensional state space coordinate system with the current hot air pressure value as the horizontal axis and the current instantaneous descent rate as the vertical axis; The pressure value at the current sampling moment and the instantaneous rate of decrease are mapped to a discrete point in the state space, and the discrete points of multiple consecutive historical sampling periods are connected to form a state trajectory curve. S34: Divide the state space into multiple regions: the first region is where the pressure is higher than the first set pressure threshold and the rate is within the envelope interval; the second region is where the pressure is higher than the first set pressure threshold but the rate exceeds the envelope interval; the third region is where the pressure is lower than the first set pressure threshold and the rate is within the envelope interval; the fourth region is where the pressure is lower than the first set pressure threshold but the rate exceeds the envelope interval; execute different branch processing logic according to the region number where the current discrete point is located. S35: When the status point falls into the third area, generate a release command to proceed to step S4; When the state point falls into the second or fourth region, the target opening correction amount of the cold air vent valve is calculated based on the deviation of the current pressure value and rate, and the valve fine-tuning command is output. When the status point falls into the first region, maintain the current valve opening and continue monitoring.

3. The linkage control method for emergency shutdown of a blast furnace according to claim 2, characterized in that, S31 specifically includes the following steps: S311: The blast furnace shutdown control module collects historical operating data within a set time period before the shutdown command is triggered, extracts the characteristic values ​​of the furnace belly gas volume, the pressure difference of the material column, and the permeability index from the data, and calculates a basic resistance coefficient that characterizes the current furnace condition by weighted fusion algorithm. The basic resistance coefficient is used as the benchmark parameter for constructing the safe rate envelope interval. S312: Construct a dynamic envelope model with hot air pressure value as independent variable. The dynamic envelope model adopts a piecewise function form. The first segment is a high-pressure straight segment with pressure above the critical value. The envelope boundary maintains a constant width. The second segment is a low-pressure contraction segment with pressure below the critical value. The envelope boundary contracts nonlinearly according to the product relationship between the basic resistance coefficient and the pressure value. Two adjustable parameters are preset in the dynamic envelope model: the critical value of the contraction initiation pressure and the contraction rate coefficient. S313: Define a material layer porosity compensation factor in the low-pressure contraction section. The material layer porosity compensation factor is calculated in real time based on the furnace top material line depth detection signal. The compensation factor is multiplied by the basic resistance coefficient to obtain the corrected dynamic contraction coefficient. The original contraction rate coefficient is replaced by the dynamic contraction coefficient to achieve adaptive adjustment of the contraction rate of the envelope boundary. S314: Determine the range of the hot air pressure value based on the current real-time monitored hot air pressure value; If the pressure is higher than the critical value, the high-pressure flat segment function is called to calculate the upper and lower limits of the allowable rate of descent. If the pressure is below the critical value, the low-pressure contraction segment function, which has been corrected by the compensation factor, is called to calculate the upper and lower limits of the allowable rate of descent that dynamically tightens as the pressure decreases. The area between the two curves is the safe rate envelope interval under the current operating conditions.

4. The linkage control method for emergency shutdown of a blast furnace according to claim 2, characterized in that, S33 specifically includes the following steps: S331: The blast furnace shutdown control module calculates the dynamic scaling factor of the pressure axis and the dynamic scaling factor of the rate axis in real time based on the historical fluctuation range of the current hot blast pressure value. It divides the collected original hot blast pressure value and instantaneous drop rate value by the corresponding scaling factor and maps them to the dimensionless standardized coordinate system. S332: Construct a circular trajectory buffer, store N consecutive standardized coordinate points in the order of sampling time, each coordinate point contains dimensionless pressure and dimensionless velocity values; calculate the Euclidean distance and orientation angle between two adjacent points in the buffer in real time, and generate displacement vector sequence and orientation angle sequence; S333: Process the sequence of coordinate points in the trajectory buffer, set the window length L, calculate the least squares fitted quadratic curve of the coordinate points in the current window in each sampling period, calculate the curvature value at the center point of the window, and record the rate of change of curvature over time. S334: Input the curvature value and curvature change rate of the current window into a pre-trained trajectory classifier. The classifier outputs the matching degree between the current trajectory and the preset smooth depressurization standard trajectory template. The matching degree, current state point coordinates, and trajectory buffer data are packaged and used as input parameters for step S34.

5. The linkage control method for emergency shutdown of a blast furnace according to claim 2, characterized in that, S35 specifically includes the following steps: S351: Receive output area identifier and current instantaneous descent rate Vcur, current safe envelope interval boundary values ​​Vmin and Vmax; When the region is identified as the second or fourth region, calculate the static deviation ΔV = Vcur - (Vmin + Vmax) / 2, and calculate the dynamic trend deviation ΔVtrend = (Vcur - Vpre) / T - dVref, where Vpre is the instantaneous descent rate of the previous sampling period, T is the sampling period, and dVref is the preset expected rate of change. Multiply the static deviation and dynamic trend deviation by the weighting coefficients α and β respectively, and then sum them to obtain the comprehensive deviation ΔVco = α·ΔV + β·ΔVtrend; S352: Obtain the current hot air pressure value Pcur; Configure three pressure ranges and their corresponding basic gain coefficients Kpbase1, Kpbase2, and Kpbase3, as well as a rate correction coefficient γ; select the corresponding basic gain Kpbase according to the range where Pcur is located, and then calculate the gain correction factor δ=1+γ·|Vcur| / Vmax according to the current instantaneous descent rate Vcur. Multiply the basic gain by the correction factor to obtain the adaptive gain Kp=Kpbase·δ. S353: Receive the comprehensive deviation ΔVco and adaptive gain Kp, calculate the original correction amount ΔOpe=Kp·ΔVco; read the current opening degree Opencur of the cold air vent valve, and obtain the preset single-step maximum allowable adjustment amount ΔOpenmax and valve opening limit value [Openmin,Openmax]; Limit the amplitude of ΔOpe. If |ΔOpe|>ΔOpenmax, then let ΔOpenlimited=sign(ΔOpe)·ΔOpenmax; otherwise, ΔOpenlimited=ΔOpe. Calculate the target opening degree Opentarget = Opencur + ΔOpenlimited, and limit it within the range of [Openmin, Openmax]. Output Opentarget to the cold air vent valve actuator.

6. The linkage control method for emergency shutdown of a blast furnace according to claim 1, characterized in that, S5 specifically includes the following steps: S51: The blast furnace shutdown control module collects the cold air release valve opening feedback signal and the real-time blast furnace pressure value in real time, and performs dual parameter value comparison with the third preset opening degree and the second set pressure threshold respectively. S52: After confirming that the opening degree of the cold air vent valve meets the standard and the pressure inside the furnace meets the standard, output the opening drive signal; S53: Continuously collect the real-time opening degree of the steam valve on the furnace top and determine whether the steam valve has reached the 100% fully open position; S54: After confirming that the steam valve is fully open, perform electrical locking of the steam valve drive circuit and collect the pressure of the steam pipeline at the top of the furnace to determine if the pressure meets the standard. S55: After the circuit is locked and the steam pipeline pressure reaches the target, output a full-open command to control the furnace top vent valve to operate to the full-open position.

7. The linkage control method for emergency shutdown of a blast furnace according to claim 5, characterized in that, In step S4, during the gradient adjustment process, the preset time interval is adjusted according to the real-time monitoring value of the furnace top pressure.

8. The linkage control method for emergency shutdown of a blast furnace according to claim 7, characterized in that, In step S4, during the gradient adjustment process, adjusting the preset time interval based on the real-time monitoring value of the furnace top pressure specifically includes the following steps: S41: The blast furnace shutdown control module collects the measured value of the furnace top pressure in real time and performs noise reduction processing on the collected pressure data; S42: Retrieve historical and real-time data from the pressure timing buffer, calculate the furnace top pressure deviation and pressure change rate, divide the adjustment interval based on the quantified values ​​of the deviation and change rate, and determine the time interval adjustment direction and basic adjustment amount. S43: Based on the adjustment direction and the basic adjustment amount, calculate the time interval after real-time adjustment, lock the adjustment parameters, and apply them to the gradient opening adjustment of the cold air vent valve.

9. The linkage control method for emergency shutdown of a blast furnace according to claim 1, characterized in that, In S3, if the condition is not met, the opening of the cold air vent valve will be adjusted according to the current hot air pressure status.

10. A linkage control system for emergency shutdown of a blast furnace, characterized in that, The system is used to implement the linkage control method steps for emergency shutdown of blast furnace as described in any one of claims 1 to 9; This includes: blast furnace shutdown control module, hot blast stove system, blower system, TRT system, bag filter dust collection system, furnace top equipment, ore and coke bin system, pulverized coal injection system, and water system; The blast furnace shutdown control module is connected to the hot blast stove system, blower system, TRT system, bag filter dust collector system, furnace top equipment, ore and coke bin system, pulverized coal injection system and water system respectively; The coke oven system and the pulverized coal injection system form the feed branch to the furnace; the blower system and the hot blast stove system form the air supply branch; the furnace top equipment, the TRT system and the bag filter system form the gas treatment branch; and the water system is the common cooling branch for the entire system. The blast furnace shutdown control module executes the emergency shutdown linkage control of the blast furnace according to the sequence of cutting off the material first, then cutting off the heat, then treating the gas, and finally stopping the blast.

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