Method for precise oxygen supply and controlled post-combustion of high-co flue gas of a metallurgical furnace

Abstract

The present application provides a kind of metallurgical furnace high CO flue gas precision oxygen supply and controlled post-combustion method, including the parameterization model based on limited flue structure and operating parameter;Real-time acquisition of flue gas state, oxygen supply and wall temperature parameter generates working condition state vector;Based on model and state vector, calculate ignition position, combustion length, CO conversion rate, outlet residual oxygen, wall temperature maximum and deposition risk index;According to the above index, determine whether the working condition is in the controlled post-combustion window that meets the safety burnout, low residual oxygen, less dilution and no bonding multi-objective constraint;S5 when the working condition is outside the window, control correction amount is generated based on rule control or multi-objective collaborative optimization strategy, adjust oxygen supply parameters and flow organization parameters to make the post-combustion process return to the window.Inside.The present application can realize the safe controlled post-combustion of high CO metallurgical flue gas in limited flue, while ensuring efficient combustion of CO, inhibiting the risk of over-temperature, high residual oxygen and bonding deposition before the inlet of waste heat boiler.

Description

Technical Field

[0001] This invention relates to the field of metallurgical flue gas treatment technology, and more specifically, to a method for precise oxygen supply and controlled afterburning of high-CO flue gas from metallurgical furnaces. Background Technology

[0002] In metallurgical processes, gases such as blast furnace gas, converter gas, and electric furnace flue gas often contain large amounts of carbon monoxide. These high-CO metallurgical flue gases are characterized by high calorific value, large fluctuations in composition, and high dust content. To recover waste heat from the flue gas and meet environmental emission requirements, CO usually needs to be completely burned before entering the waste heat boiler. Due to the limited space in the flue, the afterburning process must be completed within a limited length of flue, and it is necessary to avoid local overheating that leads to slagging and deposition on the walls, as well as excessive oxygen supply that causes flue gas dilution and energy waste.

[0003] In existing technologies, afterburning control of high-CO metallurgical flue gas mainly employs fixed air distribution or simple feedback-based regulation strategies. Oxygen supply is estimated using empirical formulas or one-dimensional combustion models, and hysteresis-based regulation is applied according to the outlet CO concentration or temperature. Some technologies introduce computational fluid dynamics (CFD) simulations for offline design optimization or use rule-based logic control to achieve graded regulation of oxygen injection. However, these methods often treat the afterburning process as a holistic combustion reaction, lacking a refined parameterized description of functional zones such as mixing, ignition, main combustion, and temperature shaping within the limited flue gas duct. This makes it difficult to accurately predict ignition location, combustion length, and temperature distribution along the flue gas wall. Furthermore, existing control strategies typically optimize a single objective (such as CO burnout rate or outlet temperature) without comprehensively considering the synergistic optimization of multiple objectives such as safe burnout, low residual oxygen, minimal dilution, and non-adhesion. This leads to problems in actual operation, such as ignition delay, combustion tailing, unburned gas before the waste heat boiler inlet, localized overheating and adhesion, or excessive dilution, making it difficult to ensure that the afterburning process remains within a controlled window.

[0004] In implementing the embodiments of the present invention, the prior art has at least the following problems or defects: It lacks a means of functional partitioning and discretized parameter modeling of the afterburning process in a limited flue, resulting in insufficient accuracy in predicting ignition position and combustion length; it has not established a multi-objective controlled afterburning window determination mechanism that integrates ignition position, combustion length, CO conversion rate, outlet residual oxygen, wall temperature, and deposition risk, making it impossible to comprehensively assess the safety and economy of the afterburning process; existing control strategies are difficult to achieve multi-objective coordinated optimization and adjustment of oxygen supply parameters and flow organization parameters when operating conditions fluctuate, causing the afterburning process to easily deviate from the controlled window, leading to risks such as incomplete combustion, overheating adhesion, or excessive dilution. Summary of the Invention

[0005] This invention provides a method for precise oxygen supply and controlled afterburning of high-CO flue gas in metallurgical furnaces, comprising the following steps: S1: Based on the structural and operational parameters of the finite flue, a parameterized model is constructed to describe the aftercombustion process of high-CO metallurgical flue gas. The parameterized model is used to perform functional partitioning, control unit discretization, and parameter definition of the finite flue. S2: Real-time acquisition of flue gas state parameters, oxygen supply state parameters, and wall temperature parameters at the inlet and outlet of the limited flue, and generation of the current operating condition state vector based on the acquired parameters; S3: Based on the parameterized model and the current operating condition vector, calculate the ignition position, combustion length, carbon monoxide conversion rate, outlet residual oxygen index, maximum wall temperature, and deposition risk index of the afterburning process; S4: Based on the ignition position, the combustion length, the carbon monoxide conversion rate, the outlet residual oxygen index, the maximum wall temperature, and the deposition risk index, determine whether the current operating condition is within the controlled afterburning window. The controlled afterburning window simultaneously meets the multi-objective constraints of safe burnout, low residual oxygen, low dilution, and non-adhesion. S5: When it is determined that the current operating condition is outside the controlled afterburning window, a control correction amount is generated based on the rule control strategy or the multi-objective collaborative optimization strategy, and the oxygen supply parameters and flow organization parameters are adjusted according to the control correction amount so that the afterburning process returns to the controlled afterburning window.

[0006] Furthermore, the functional zoning of the limited flue in S1 includes: dividing the limited flue along the main flue gas direction into a mixing initiation zone, an ignition formation zone, a main combustion zone, a temperature shaping zone, and a waste heat boiler inlet constraint zone; The discretization of the control unit includes: discretizing the finite flue along the main flue gas direction into N controlled afterburning control units, each of which serves as the minimum addressing unit for afterburning process calculation, risk assessment, and control adjustment, where N is an integer greater than 1; The parameter definition includes: establishing a parameter set for the i-th control unit, the parameter set including the axial distance from the center position of the control unit to the inlet of the finite flue, the axial length of the control unit, the flow cross-sectional area of ​​the control unit, the wetted perimeter of the control unit, the hydraulic diameter of the control unit, the average axial velocity of the flue gas cross section in the control unit, the flue gas pressure in the control unit, the average temperature of the flue gas in the control unit, the volume fraction of carbon monoxide in the control unit, the volume fraction of oxygen in the control unit, the volume fraction of water vapor in the control unit, the flue gas density in the control unit, and the total molar flow rate of the flue gas in the control unit, where i is an integer from 1 to N.

[0007] Furthermore, the parameterized model in S1 also includes a set of overall parameterized descriptions for the entire finite flue. The set of overall parameterized descriptions includes the effective length of the finite flue, the characteristic hydraulic diameter of the finite flue, the axial distance from the oxygen injection position to the flue inlet, the position of the flow organization components, the inlet position of the waste heat boiler, the afterburning ignition position, the combustion length of the main combustion zone, the outlet velocity of the oxygen injection jet, the flue gas inlet temperature, the volume fraction of carbon monoxide at the flue gas inlet, the volume fraction of oxygen at the flue gas inlet, and the volume fraction of water vapor at the flue gas inlet.

[0008] Furthermore, the parameters collected in real time in S2 include: carbon monoxide concentration at the inlet and outlet, oxygen concentration, flue gas temperature, flue gas velocity, oxygen flow rate, oxygen injection pressure, and oxygen injection position of each oxygen supply branch, position of the cyclone separator or flow organization component, and wall temperature near the inlet of the waste heat boiler. The current operating condition state vector includes ignition position, combustion length, carbon monoxide conversion rate, outlet residual oxygen index, flue gas dilution index, maximum wall temperature in the assessment section, maximum deposition risk index in the assessment section, and sampling time of the current control cycle.

[0009] Furthermore, the calculation of the ignition position in S3 includes: starting from the oxygen injection position, calculating the cumulative residence time, local oxygen matching coefficient and equivalent ignition delay time for each control unit along the flue gas flow direction, and determining the center position of the first control unit that simultaneously meets the mixing-ignition matching conditions, the temperature after mixing is not less than the afterburning critical ignition temperature and the local oxygen matching coefficient is within the allowable range as the ignition position. The cumulative residence time is obtained by summing the ratios of the length of each control unit to the average axial velocity of the flue gas; the local oxygen matching coefficient is calculated based on the ratio of the molar flow rate of oxygen that can participate in the carbon monoxide oxidation reaction within the control unit to half of the molar flow rate of carbon monoxide; the equivalent ignition delay time is calculated based on the ignition rate pre-factor, equivalent ignition activation energy, universal gas constant, local temperature after mixing, carbon monoxide molar concentration, oxygen molar concentration, reaction order correction coefficient, humidity correction function, and flow organization correction coefficient.

[0010] Furthermore, the calculation of the combustion length in S3 includes: starting from the control unit corresponding to the ignition position, calculating the carbon monoxide consumption molar flow rate unit by unit along the flue gas flow direction based on the carbon monoxide oxidation reaction rate, and defining the control unit position where the cumulative carbon monoxide conversion rate first reaches the preset burnout target value as the main combustion end position, and the combustion length is calculated based on the difference between the main combustion end position and the ignition position; The formula for calculating the rate of carbon monoxide oxidation reaction is as follows: in, Let be the carbon monoxide oxidation reaction rate within the i-th control unit. Here, ECO is the pre-rate factor for carbon monoxide oxidation, R is the apparent activation energy for carbon monoxide oxidation, and ECO is the universal gas constant. Let be the average temperature of the flue gas in the i-th control unit. and These are the molar concentrations of carbon monoxide and oxygen, respectively. and These are the reaction order correction factors for carbon monoxide and oxygen, respectively. This is a humidity correction function; The formula for calculating the burning length is: in, For the length of combustion, This refers to the position where the main combustion ends. The ignition position is described above.

[0011] Furthermore, the calculation of the maximum wall temperature in S3 includes: based on the heat release distribution and flue gas temperature distribution, calculating the wall temperature of each control unit in the waste heat boiler inlet constraint zone through the gas-solid wall heat transfer model, and determining the maximum wall temperature in this zone as the maximum wall temperature. The deposition risk index calculated in S3 includes a weighted average of the wall temperature risk term, the low-velocity deposition risk term, and the particle concentration risk term. The calculation formula for the deposition risk index is as follows: in, As a sedimentation risk indicator, For wall temperature risk items, This is a risk factor for low-velocity deposition. For particulate concentration risk items, These are the weights for the wall temperature risk term, the low-velocity deposition risk term, and the particle concentration risk term, respectively, and they satisfy the following conditions: .

[0012] Furthermore, the determination conditions for the controlled afterburning window in S4 include: the sum of the ignition position and the combustion length is less than or equal to the difference between the waste heat boiler inlet position and the safety buffer distance; the carbon monoxide conversion rate is greater than or equal to the preset burnout target value; the outlet residual oxygen index is less than or equal to the allowable upper limit; the maximum wall temperature is less than or equal to the allowable wall temperature; and the deposition risk index is less than or equal to the allowable upper limit. The set of controlled afterburning windows is represented as follows: Where W represents the controlled afterburn window, For the overall parameterized description set, This is the ignition position. For the length of combustion, This is the inlet location of the waste heat boiler. A safety buffer distance is reserved before the inlet of the waste heat boiler. The carbon monoxide conversion rate, The target value for carbon monoxide conversion rate. For export residual oxygen indicators, This is the upper limit for the permitted residual oxygen for export. This represents the maximum wall temperature near the inlet of the waste heat boiler. The allowable temperature of the wall surface. As a sedimentation risk indicator, This represents the upper limit allowed for deposition risk.

[0013] Furthermore, the multi-objective collaborative optimization strategy in S5 includes: constructing a comprehensive objective function, and under the constraint of the controlled afterburning window, solving for the optimal control variable vector that minimizes the comprehensive objective function; The formula for calculating the comprehensive objective function is as follows: in, The objective function is a multi-objective collaborative optimization function, where u is a vector of control variables. The ignition position is obtained under the influence of control variables. For the target ignition location, These are the upper and lower limits of the ignition position window, respectively. The combustion length is obtained under the control of variables. For the target burning length, For a limited effective length of flue, The residual oxygen index at the outlet is obtained under the control of variables. The flue gas dilution index is obtained under the control of variables. For the maximum permissible dilution, To determine the maximum deposition risk under the control of variables, To the maximum allowable deposition risk, To obtain the maximum wall temperature under the influence of control variables, The allowable temperature of the wall surface. These are the weighting coefficients for ignition position deviation, combustion length deviation, residual oxygen level, flue gas dilution, deposition risk, and wall temperature exceedance risk, respectively.

[0014] Furthermore, the oxygen supply parameters in S5 include the oxygen injection position, oxygen molar flow rate, and oxygen jet outlet velocity of the primary oxygen supply branch, the secondary oxygen supply branch, and the optional multi-stage oxygen supplementation branch; the flow organization parameters include the position of the cyclone separator or flow organization component and the flow organization intensity parameters. The change in the control correction amount within adjacent control cycles is not greater than the preset maximum adjustment range; the control correction amount is used to convert into valve opening commands for each level of oxygen supply branch, target displacement commands for oxygen injection nozzle actuators, target angle commands for nozzle angle actuators, and target position commands for cyclone separators or flow organization component actuators.

[0015] The embodiments of the present invention have at least the following beneficial effects: 1. By functionally dividing the limited flue along the mainstream flue gas direction into mixing initiation zone, ignition formation zone, main combustion zone, temperature shaping zone, and waste heat boiler inlet constraint zone, and discretizing the flue into multiple controlled afterburning control units, a refined parametric model was established. This enabled accurate prediction of ignition position, combustion length, and flue gas state distribution along the process, solving the problem of insufficient prediction accuracy of key positions in the afterburning process caused by the lack of functional zoning and discretization modeling in existing technologies.

[0016] 2. By constructing a controlled afterburning window that simultaneously satisfies multiple objectives such as safe burnout, low residual oxygen, low dilution, and non-adhesion, and using the sum of ignition position and combustion length, carbon monoxide conversion rate, outlet residual oxygen index, maximum wall temperature, and deposition risk index as window determination conditions, a comprehensive quantitative assessment of the safety and economy of the afterburning process is achieved. This solves the problem in existing technologies where optimization based on a single objective makes it difficult to comprehensively consider burnout efficiency, energy consumption control, and equipment safety.

[0017] 3. By generating control correction quantities through rule-based control strategies or multi-objective collaborative optimization strategies, the oxygen injection position, oxygen molar flow rate, and oxygen jet outlet velocity of the primary oxygen supply branch, secondary oxygen supply branch, and multi-stage oxygen supplementation branch, as well as the position and intensity parameters of the cyclone separator or flow organization components, are coordinated and adjusted. The maximum adjustment range within adjacent control cycles is limited, which realizes rapid return and stable control of the afterburning process when the operating conditions fluctuate. This solves the problem in the prior art that the afterburning process is prone to deviating from the controlled window and causing incomplete combustion or overheating adhesion risks due to the lack of a collaborative optimization mechanism for the adjustment of oxygen supply and flow organization parameters. Attached Figure Description

[0018] The above and other objects, features, and advantages of exemplary embodiments of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings. Several embodiments of the invention are illustrated in the drawings by way of example and not limitation, wherein: Figure 1 This is a schematic flowchart of a method for precise oxygen supply and controlled afterburning of high-CO flue gas in metallurgical furnaces provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of the overall structure of a high-CO flue gas precision oxygen supply and controlled afterburning system for metallurgical furnaces provided in an embodiment of the present invention. Figure 3 This is a schematic diagram of the discrete functional partitioning and control unit of a limited flue gas duct according to an embodiment of the present invention; Figure 4 This is a schematic diagram of a graded oxygen supply and hybrid enhancement subsystem provided in an embodiment of the present invention. Detailed Implementation

[0019] The principles and spirit of the invention will now be described with reference to several exemplary embodiments. It should be understood that these embodiments are provided merely to enable those skilled in the art to better understand and implement the invention, and are not intended to limit the scope of the invention in any way. Rather, these embodiments are provided to make the invention more thorough and complete, and to fully convey the scope of the invention to those skilled in the art.

[0020] The following is for reference. Figure 1 , Figure 1 This is a schematic flowchart illustrating a method for precise oxygen supply and controlled afterburning of high-CO flue gas in metallurgical furnaces, provided in an embodiment of the present invention. Figure 1 As shown, a method for precise oxygen supply and controlled aftercombustion of high-CO flue gas in metallurgical furnaces includes: S1: Constructing a parametric model In S1, a parameterized model is first constructed based on the structural and operational parameters of a finite flue to describe the afterburning process of high-CO metallurgical flue gas. A finite flue refers to a section of flue gas with a defined length and cross-section connecting the flue gas outlet of a side-blown smelting furnace and the inlet of a waste heat boiler; its internal flow space provides the basic environment for the afterburning reaction. A side-blown smelting furnace is a large-scale non-ferrous metallurgical device, used for oxygen-enriched smelting of metals such as copper and nickel; its exhaust gas is characterized by high temperature, high CO, high SO2, and high dust content. The waste heat boiler is a heat exchange device installed downstream of the flue to recover the sensible heat of the high-temperature flue gas. High-CO metallurgical flue gas refers to high-temperature smelting flue gas from a side-blown smelting furnace containing high concentrations of carbon monoxide, high concentrations of sulfur dioxide, and a large amount of dust, with a typical carbon monoxide volume fraction of 5% to 15% and a typical temperature of 900℃ to 1200℃. The parameterized model is used to functionally partition the finite flue, discretize control units, and define parameters.

[0021] See Figure 3The schematic diagram of the axial functional zoning and control unit of the limited flue gas duct shown divides the duct into five functional zones along the main flue gas flow direction: mixing initiation zone, ignition formation zone, main combustion zone, temperature shaping zone, and waste heat boiler inlet constraint zone. The mixing initiation zone mainly corresponds to the initial entrainment and mixing process after the oxygen jet enters the main flue gas. The oxygen jet refers to the stream of oxygen injected into the flue gas through a spray gun, used to oxidize carbon monoxide in the flue gas. The ignition formation zone mainly corresponds to the area where a local combustible mixture forms and reaches the critical ignition condition. The main combustion zone mainly corresponds to the area where CO afterburning reaction occurs concentratedly and heat release increases rapidly. The temperature shaping zone is used to limit excessive heat peak concentration and promote a more gradual temperature distribution in the flue gas. The waste heat boiler inlet constraint zone is used to ensure that the residual oxygen level, wall temperature, and particle deposition tendency of the flue gas before entering the waste heat boiler are within acceptable ranges.

[0022] The finite flue is discretized into N controlled afterburning control units along the main flue gas direction. Each control unit serves as the smallest addressable unit for afterburning process calculation, risk assessment, and control regulation. Control unit discretization refers to dividing the continuous flue space into several small segments, where the flow and reaction parameters are considered uniform. In practical implementation, the value of N can be determined based on the flue length and calculation accuracy. For example, when the effective length of the finite flue is 10 meters, N can be taken as 50 to 100. The axial length of each control unit... The distance is 0.1 meters to 0.2 meters. The control unit numbers are sequentially assigned starting from the flue inlet. For the i-th control unit Establish the following parameter set: The meanings of each symbol are as follows: Let be the axial distance from the center position of the i-th control unit to the inlet of the finite flue. Let be the axial length of the i-th control unit. Let be the flow cross-sectional area of ​​the i-th control unit. The wetted perimeter of the i-th control unit is the portion of the flue gas section that is in contact with the flue gas. The hydraulic diameter of the i-th control unit is used to characterize the equivalent diameter of the non-circular cross-section. Let be the average axial velocity of the flue gas cross section within the i-th control unit. Let be the flue gas pressure in the i-th control unit. Let be the average temperature of the flue gas in the i-th control unit. These represent the volume fractions of carbon monoxide, oxygen, and water vapor within the i-th control unit, respectively. Let be the smoke density within the i-th control unit. The total molar flow rate of flue gas in the i-th control unit is the total amount of flue gas flowing through the control unit per unit time.

[0023] S11: Functional Partitions In S11, the functional zoning of the limited flue gas duct specifically includes dividing the limited flue gas duct along the mainstream flue gas direction into a mixing initiation zone, an ignition formation zone, a main combustion zone, a temperature shaping zone, and a waste heat boiler inlet constraint zone. For example... Figure 3 As shown, from the flue inlet to the oxygen injection position The area between these points is the mixing initiation zone; from the oxygen injection position to the ignition position. The area between these points is the ignition formation zone; from the ignition position to the end of the main combustion phase. The area between them is the main combustion zone; from the end of the main combustion phase to the inlet of the waste heat boiler. The area between these two points is the temperature shaping zone; the area near the inlet of the waste heat boiler is the waste heat boiler inlet constraint zone.

[0024] S12: Discrete control unit In S12, the discretization of the control unit specifically includes: discretizing the finite flue along the mainstream flue gas direction into N controlled afterburning control units, denoted as... ,in Each control unit serves as the smallest addressable unit for afterburner process calculations, risk assessment, and control regulation. In industrial control systems, the parameters of each control unit can be stored using an array structure of a Programmable Logic Controller (PLC) or a Distributed Control System (DCS). A PLC is an industrial digital computer used for automation control; a DCS is a distributed control system used for process control. For example, in a Siemens S7-1500 PLC, a data block DB_ControlVolume can be created, defining a structured array of length N, with each element containing the aforementioned parameter variables.

[0025] S13: Parameter Definition In S13, the parameter definition specifically includes: for the first Control unit Establish the parameter set as described in S1. Among them, the hydraulic diameter... Calculate according to the following formula: In the formula, For the first The flow cross-sectional area of ​​each control unit For the first The wetted perimeter of each control unit. This formula is used to equate the flow characteristics of a non-circular cross-section to a circular cross-section. Total molar flow rate of flue gas. Approximate calculation based on the ideal gas state relation: In the formula, For the first Flue gas pressure within each control unit For the first Average axial velocity of flue gas cross section within each control unit For the cross-sectional area of ​​circulation, The universal gas constant is taken as 8.314 joules per mole per Kelvin. For the first The average flue gas temperature within each control unit. This formula is based on the ideal gas law. It is derived.

[0026] S111: Overall parameterized description set In S111, the parametric model also includes a set of overall parametric descriptions of the entire finite flue, expressed as: The meanings of the symbols in the formula are as follows: For a limited effective length of flue, Given the characteristic hydraulic diameter of a finite flue, This is the axial distance from the oxygen injection point to the flue inlet. The location of flow organization components, including devices such as cyclones and guide vanes, is used to change the flow field structure within the flue. This is the inlet location of the waste heat boiler. This is the afterburner ignition position. Combustion length of the main combustion zone The outlet velocity of the oxygen jet. The flue gas inlet temperature, These represent the volume fractions of carbon monoxide, oxygen, and water vapor at the flue gas inlet.

[0027] S2: Real-time acquisition and generation of operating condition vectors In S2, real-time data is collected on flue gas state parameters, oxygen supply state parameters, and wall temperature parameters at the inlet and outlet of the confined flue. Based on the collected parameters, a current operating condition state vector is generated. In specific implementation, the following method is used: Figure 2 The multi-stage oxygen supply pipeline system and actuator group shown includes an online sensing module. This module comprises flue gas component detection devices such as infrared gas analyzers, temperature detection devices such as K-type thermocouples, pressure detection devices such as pressure transmitters, flow detection devices such as vortex flow meters, and dust concentration detection devices such as light scattering dust meters.

[0028] The collected parameters include: carbon monoxide concentration, oxygen concentration, flue gas temperature, and flue gas velocity at the inlet and outlet; oxygen flow rate, injection pressure, and injection location of each oxygen supply branch; location of cyclones or flow organization components; and wall temperature near the inlet of the waste heat boiler. Based on the above real-time data, the control is performed according to the set control cycle. Generate the current operating condition state vector. The control cycle refers to the time interval between two sampling and adjustment operations of the control system. The typical value ranges from 1 second to 5 seconds. This occurs at the sampling time of the j-th control cycle. The state vector is represented as: The meanings of the symbols in the formula are as follows: Let be the afterburning state vector for the j-th control cycle. This is the ignition position. For the length of combustion, The carbon monoxide conversion rate is the ratio of the difference between inlet CO and outlet CO to the inlet CO content. The residual oxygen index at the outlet is the volume fraction of oxygen before the waste heat boiler inlet. The flue gas dilution index is used to characterize the degree to which oxygen injection increases the total amount of flue gas. To assess the maximum wall temperature within the section, To assess the maximum depositional risk index within the section, This is the sampling time of the j-th control cycle.

[0029] S21: Specific Acquisition Parameters In S21, the specific parameters collected in real time include: carbon monoxide concentration at the inlet and outlet, oxygen concentration, flue gas temperature, flue gas velocity, oxygen flow rate, injection pressure, and injection location of each oxygen supply branch, location of cyclones or flow organization components, and wall temperature near the inlet of the waste heat boiler. Figure 2 Taking the system shown as an example, a flue gas sampling probe is installed on the outlet flue of the side-blown smelting furnace. The flue gas is introduced into the analysis cabinet through a heat tracing pipeline. A multi-component infrared gas analyzer is installed inside the analysis cabinet to measure the CO and O2 concentrations. The flue gas velocity is measured by a Pitot tube in conjunction with a differential pressure transmitter. The Pitot tube is a flow velocity measurement device based on Bernoulli's principle. The oxygen injection position of each oxygen supply branch is fed back by displacement sensors installed on the spray gun actuator, such as a pull-wire displacement sensor.

[0030] S22: Generate state vector In S22, the specific form for generating the current operating condition state vector is as described in S2. In the PLC program, a structure variable can be created. , containing member variables Each member is a floating-point number. At the end of each control cycle, the values ​​of these members are updated by calling the corresponding function block.

[0031] S3: Calculate afterburning process parameters In S3, based on the parametric model and the current operating condition state vector, the ignition position, combustion length, carbon monoxide conversion rate, outlet residual oxygen index, maximum wall temperature, and deposition risk index of the afterburning process are calculated. These calculations are performed in an industrial control computer or embedded industrial controller, and can be implemented using high-level languages ​​such as C++ or structured text programming (ST). Structured text is a high-level language similar to Pascal used in PLC programming.

[0032] S31: Calculate ignition position In S31, calculating the ignition position includes: starting from the oxygen injection position, calculating the cumulative residence time, local oxygen matching coefficient, and equivalent ignition delay time for each control unit along the flue gas flow direction. The center position of the first control unit that simultaneously meets the mixing-ignition matching conditions, has a mixed temperature not lower than the afterburning critical ignition temperature, and has a local oxygen matching coefficient within the allowable range is determined as the ignition position. Residence time refers to the time it takes for the flue gas to flow from the oxygen injection position to the current control unit. The local oxygen matching coefficient characterizes the ratio of the actual oxygen content in the control unit to the theoretical oxygen content required for complete CO combustion. The equivalent ignition delay time refers to the time required for the mixture to reach the ignition conditions.

[0033] Total stay time Calculate using the following formula: In the formula, For the first Length of each control unit For the first Average axial velocity of flue gas within each control unit For the first The control unit number corresponding to the oxygen injection position of the primary oxygen injection branch.

[0034] Local oxygen matching coefficient Calculate using the following formula: In the formula, For the first The molar flow rate of oxygen that can participate in the carbon monoxide oxidation reaction within each control unit. For the first The molar flow rate of carbon monoxide within each control unit. The coefficient 0.5 is derived from the carbon monoxide oxidation reaction equation: .

[0035] Equivalent ignition delay time Calculate using the following formula:

[0036] In the formula, For the first Equivalent ignition delay time within each control unit Let i be the equivalent ignition rate within the i-th control unit. Typical values ​​are taken for the ignition rate pre-factor. , Typical values ​​are taken for the equivalent ignition activation energy. Joules per mole, where R is the universal gas constant. Let be the local temperature after mixing within the i-th control unit. Here, a and b are the molar concentrations of carbon monoxide and oxygen, respectively, and a and b are reaction order correction factors, typically taken as... , The humidity correction function is used to characterize the promoting effect of water vapor on CO oxidation. It represents the volume fraction of water vapor. The flow structure correction factor is used to characterize the enhancing effect of components such as cyclones on ignition.

[0037] Local temperature after mixing Calculate using the following formula: In the formula, Let be the total molar flow rate of flue gas in the i-th control unit. The average isobaric heat capacity of the main flue gas is the amount of heat absorbed by a unit amount of substance when the flue gas temperature increases by 1 Kelvin. Let be the average temperature of the flue gas in the i-th control unit. The allocation coefficient for the k-th level oxygen supply to the i-th control unit ranges from 0 to 1. The total molar flow rate of the oxygen supply medium in the kth stage is... The average isobaric heat capacity of the oxygen supply medium in the kth stage is given. The temperature of the oxygen supply medium at stage k is given.

[0038] Hybrid-ignition matching conditions are Mixed feature time Calculate using the following formula: In the formula, This is a mixed-scale correction factor. Let be the hydraulic diameter of the i-th control unit. The intensity of flow disturbance within the i-th control unit is used to characterize the severity of turbulent mixing. Let be the average axial velocity of the flue gas in the i-th control unit. The mixture-ignition matching factor is typically taken as 1.0 to 2.0. Afterburning critical ignition temperature. This refers to the lowest temperature at which a mixture of carbon monoxide and oxygen can spontaneously ignite, typically taken as 973 K. The lower limit of the permissible range for the local oxygen matching coefficient. Take 0.8, upper limit Take 1.5.

[0039] The above parameters are calculated sequentially along the axial direction of the finite flue, starting from the control unit corresponding to the oxygen injection position. The first control unit that simultaneously satisfies the above conditions is selected. its central position This is the ignition position. .

[0040] S311: Calculate the burning length In S311, the calculation of combustion length includes: starting from the control unit corresponding to the ignition position, calculating the carbon monoxide consumption molar flow rate unit by unit along the flue gas flow direction based on the carbon monoxide oxidation reaction rate, and defining the control unit position where the cumulative carbon monoxide conversion rate first reaches the preset burnout target value as the main combustion end position. The combustion length is calculated based on the difference between the main combustion end position and the ignition position. The carbon monoxide oxidation reaction rate refers to the rate at which carbon monoxide is oxidized by oxygen per unit volume.

[0041] Carbon monoxide oxidation reaction rate Calculate using the following formula: In the formula, Let be the carbon monoxide oxidation reaction rate within the i-th control unit. Typical values ​​are taken for the pre-oxidation rate factor of carbon monoxide. , Typical values ​​are taken for the apparent activation energy of carbon monoxide oxidation. Joules per mole, where R is the universal gas constant. Let be the average temperature of the flue gas in the i-th control unit. a1 and a2 are the molar concentrations of carbon monoxide and oxygen, respectively, and the reaction order correction factors for carbon monoxide and oxygen are the molar concentrations of oxygen, respectively. This is the humidity correction function.

[0042] CO consumption molar flow rate within the i-th control unit ,in Let be the volume of the control unit. Starting from the control unit q corresponding to the ignition position, calculate the remaining CO molar flow rate unit by unit. Accumulate the calculation from the ignition position up to the b-th control unit; if the cumulative CO conversion rate satisfies... Then the center position of the control unit is defined as the main combustion end position. The preset burnout target value This is the lower limit of the required carbon monoxide conversion rate, typically 0.95. Combustion length. Calculate using the following formula: In the formula, At the end of the main combustion phase This indicates the ignition position.

[0043] S34: Calculate the maximum wall temperature In S34, calculating the maximum wall temperature includes: based on the heat release distribution and flue gas temperature distribution, calculating the wall temperature of each control unit within the waste heat boiler inlet confinement zone using a gas-solid wall heat transfer model, and determining the maximum wall temperature within this zone as the maximum wall temperature. The heat release distribution refers to the distribution of heat released by the afterburning reaction along the flue axial direction. The gas-solid wall heat transfer model is used to calculate the heat transfer between the high-temperature flue gas and the flue wall. A convection heat transfer model can be used. ,in For flue gas temperature, For heat flux density, For wall thickness, The thermal conductivity of the wall material. The convective heat transfer coefficient on the flue gas side. Calculated using the Dittus-Boelter formula: ,in Let be the thermal conductivity of the flue gas, Re be the Reynolds number, and Pr be the Prandtl number. In industrial control systems, wall temperature calculation can be simplified to a modified empirical formula based on the location of the heat release peak. The coefficients are pre-calibrated through finite element simulation to form a lookup table function. Within the confined zone at the inlet of the waste heat boiler, the maximum wall temperature of all control units is taken as... .

[0044] S35: Calculate sedimentation risk indicators In S35, the deposition risk index is calculated by weighting three factors: wall temperature risk, low-velocity deposition risk, and particle concentration risk. The deposition risk index is used to assess the likelihood of dust-laden flue gas adhering to, forming nodules, and clogging the flue gas wall. The wall temperature risk reflects the risk of particle softening due to excessively high wall temperatures; the low-velocity deposition risk reflects the risk of particle settling due to excessively low flue gas velocity; and the particle concentration risk reflects the risk of accelerated deposition due to excessively high dust concentration. Deposition Risk Index Calculate using the following formula: In the formula, Deposition risk indicators For wall temperature risk items, This is a risk factor for low-velocity deposition. For particulate concentration risk items, These are the weights for the wall temperature risk term, the low-velocity deposition risk term, and the particle concentration risk term, respectively, and they satisfy the following conditions: .

[0045] Wall temperature risk item Calculate using the following formula: In the formula, The wall temperature, The particle softening temperature is the temperature at which particles begin to soften and become adhesive. This is the particle melting temperature, i.e., the temperature at which the particles completely melt. For typical copper smelting fumes... Approximately 1073K, It is approximately 1373K.

[0046] Low-speed deposition risk item Calculate using the following formula: In the formula, The critical flue gas velocity required to suppress particulate deposition is typically 3 to 5 m / s. This refers to the local flue gas velocity.

[0047] Particle concentration risk item Calculate using the following formula: In the formula, Let be the particle mass concentration within the i-th control unit. The preset reference particle concentration is typically 50 grams per cubic meter.

[0048] The maximum value of the deposition risk index of each control unit within the confined area of ​​the waste heat boiler inlet is taken as... .

[0049] S4: Determine the controlled afterburn window In S4, based on the ignition location, combustion length, carbon monoxide conversion rate, outlet residual oxygen index, maximum wall temperature, and deposition risk index, it is determined whether the current operating condition is within the controlled afterburning window. The controlled afterburning window refers to the operating condition range that simultaneously meets multiple target constraints, including safe burnout, low residual oxygen, minimal dilution, and non-adhesion. Safe burnout requires sufficient CO oxidation to avoid excessive emissions or downstream explosions; low residual oxygen requires a low outlet oxygen concentration to facilitate subsequent acid production; minimal dilution requires a moderate oxygen injection rate to avoid excessive increase in flue gas volume; and non-adhesion requires wall temperature and deposition risk to be controlled within allowable ranges to avoid nodulation and blockage. The determination criteria include: the sum of the ignition location and combustion length is less than or equal to the difference between the waste heat boiler inlet location and the safe buffer distance; the carbon monoxide conversion rate is greater than or equal to the preset burnout target value; the outlet residual oxygen index is less than or equal to the allowable upper limit; the maximum wall temperature is less than or equal to the allowable wall temperature; and the deposition risk index is less than or equal to the allowable upper limit.

[0050] The set of controlled afterburning windows is represented as: In the formula, W is the controlled afterburn window. For the overall parameterized description set, This is the ignition position. For the length of combustion, This is the inlet location of the waste heat boiler. A safety buffer distance is reserved before the inlet of the waste heat boiler. The carbon monoxide conversion rate, The target value for carbon monoxide conversion rate. For export residual oxygen indicators, This is the upper limit for the permitted residual oxygen for export. This represents the maximum wall temperature near the inlet of the waste heat boiler. The allowable temperature of the wall surface. As a sedimentation risk indicator, This represents the upper limit allowed for deposition risk.

[0051] S41: Window Decision Condition In S41, the criteria for determining the controlled afterburning window specifically include the five inequalities mentioned above. Among these, the safety buffer distance... The values ​​are determined based on the allowable fluctuation range of the flue gas temperature at the inlet of the waste heat boiler, the risk of ash accumulation on the first heat-receiving surface, the safety margin of the inlet wall temperature, and engineering operation experience. The typical range is 0.3 meters to 1.5 meters.

[0052] S42: Window set representation In S42, the set of controlled afterburning windows is represented as shown in Equation W above. In engineering applications, this set can be visualized using a two-dimensional table or contour plot. For example, it can be represented by the oxygen injection location. and total oxygen supply Using the coordinate axes, the region satisfying all constraints is plotted in the coordinate system; this is the afterburner window. Operators can check via the human-machine interface whether the current operating point is within this window.

[0053] S5: Generate control correction amount and adjust In S5, when the current operating condition is determined to be outside the controlled afterburning window, a control correction amount is generated based on a rule-based control strategy or a multi-objective collaborative optimization strategy. The oxygen supply parameters and flow organization parameters are then adjusted according to this control correction amount to bring the afterburning process back within the controlled afterburning window. The control correction amount refers to the adjustment amount that needs to be applied to the actuator. The rule-based control strategy is a logical judgment rule based on engineer experience, while the multi-objective collaborative optimization strategy obtains the optimal adjustment amount by solving an optimization problem. The control strategy adopts a hierarchical structure: when the operating condition is near the window boundary and the deviation is not severe, the multi-objective collaborative optimization strategy is used first; when the operating condition seriously exceeds the limit or a safety warning occurs, the rule-based control strategy is immediately invoked for rapid correction.

[0054] Typical examples of rules for rule-based control strategies are as follows: If If the oxygen flow rate is below the allowable lower limit and the wall temperature rises rapidly, prioritize reducing the oxygen flow rate of the primary oxygen supply branch or decreasing the oxygen injection speed, while simultaneously moving the primary oxygen injection position to the later stage; if Greater than the allowed limit or near If the oxygen supply ratio of the secondary oxygen supply branch is increased, the flow rate of the mid-section injection is enhanced, and the main combustion zone is moved forward. If the residual oxygen at the outlet is high for a long period of time, the oxygen flow rate of the excess oxygen supply branch is reduced and the oxygen supply ratio of each stage is redistributed. If the deposition risk index increases, the intensity of the cyclone separator is adjusted or the oxygen injection angle is changed.

[0055] S51: Multi-objective collaborative optimization strategy In S51, the multi-objective collaborative optimization strategy includes: constructing a comprehensive objective function and, under the constraint of a controlled afterburner window, solving for the optimal control variable vector that minimizes the comprehensive objective function. The comprehensive objective function quantifies the gap between the current control effect and the ideal objective; a smaller value indicates a better control effect. The comprehensive objective function... Calculate using the following formula: In the formula, To achieve multi-objective collaborative optimization of the objective function, To control the variable vector, The ignition position is obtained under the influence of control variables. For the target ignition location, These are the upper and lower limits of the ignition position window, respectively. The combustion length is obtained under the control of variables. For the target burning length, For a limited effective length of flue, The residual oxygen index at the outlet is obtained under the control of variables. The flue gas dilution index is obtained under the control of variables. For the maximum permissible dilution, To determine the maximum deposition risk under the control of variables, To the maximum allowable deposition risk, To obtain the maximum wall temperature under the influence of control variables, The allowable temperature of the wall surface. These are the weighting coefficients for ignition position deviation, combustion length deviation, residual oxygen level, flue gas dilution, deposition risk, and wall temperature exceedance risk, respectively.

[0056] The optimization solution can be implemented in industrial controllers using gradient descent, genetic algorithms, or particle swarm optimization. Gradient descent is an iterative optimization method based on derivatives, while genetic algorithms and particle swarm optimization are global optimization algorithms that simulate natural evolution or swarm intelligence.

[0057] S53: Oxygen supply parameters and flow organization parameters In S53, oxygen supply parameters include the injection locations, oxygen molar flow rates, and oxygen jet outlet velocities of the primary oxygen supply branch, secondary oxygen supply branch, and optional multi-stage oxygen supplementation branch. The primary oxygen supply branch refers to the pipeline injecting oxygen from the upstream of the flue to establish initial reaction conditions; the secondary oxygen supply branch refers to the pipeline injecting oxygen from the midstream of the flue to stabilize the main combustion zone; and the multi-stage oxygen supplementation branch refers to additional injection points for fine-tuning. See also... Figure 4The diagram illustrates a staged oxygen supply and mixing enhancement subsystem. The primary oxygen supply branch is located upstream of the mixing initiation zone to establish initial oxygen conditions; the secondary oxygen supply branch is located near the ignition formation zone to stabilize the main combustion zone; and the multi-stage oxygen supplement branch is used for fine-tuning when flue gas composition fluctuates significantly. Flow organization parameters include the location of swirlers or flow organization components and flow organization intensity parameters. A swirler is a device that induces swirling flow in the flue gas, enhancing mixing. The flow organization intensity parameter is characterized by the swirl number S, typically ranging from 0.6 to 1.2.

[0058] S54: Control Correction Constraints and Transformations In S54, the change in the control correction amount within adjacent control cycles does not exceed the preset maximum adjustment range to prevent excessively abrupt control actions that could lead to rapid migration of the main heat release zone, wall thermal shock, or severe fluctuations in flue gas temperature. For example, the maximum single adjustment range of the oxygen injection position is set to 0.1 meters, the maximum single change rate of the oxygen molar flow rate is set to 10% of the total oxygen supply, and the maximum single change rate of the oxygen jet velocity is set to 10 meters per second.

[0059] The control correction is used to convert valve opening commands for each stage of the oxygen supply branch, target displacement commands for the oxygen injection nozzle actuator, target angle commands for the nozzle angle actuator, and target position commands for the cyclone separator or flow organization component actuator. Valve opening commands control the degree of opening of the regulating valve; target displacement commands for the oxygen injection nozzle actuator control the extension and retraction position of the spray gun; target angle commands for the nozzle angle actuator control the direction of oxygen injection; and target position commands for the cyclone separator actuator control the opening of the cyclone blades.

[0060] For the k-th level oxygen supply branch, the target oxygen molar flow rate The corresponding oxygen supply medium volumetric flow rate is calculated using the following formula: In the formula, The target volumetric flow rate of the k-th oxygen supply branch is... Let R be the target oxygen molar flow rate, and R be the universal gas constant. The temperature of the oxygen supply medium at stage k is... The oxygen volume fraction in the oxygen supply medium. The nozzle pressure is used as an indicator. Then, the valve opening is calculated by referring to the flow characteristic curve of the control valve. The flow characteristic curve describes the relationship between the valve opening and the flow rate, and is usually provided by the valve manufacturer.

[0061] The target displacement command for the oxygen injection nozzle actuator is directly set to the target oxygen injection position; the target angle command for the nozzle angle actuator is directly set to the target injection angle; and the target position command for the cyclone actuator is directly set to the target flow organization component position. All execution commands are sent from the controller to the field actuators via an industrial Ethernet protocol. Industrial Ethernet protocols include Profinet or Modbus TCP. Profinet is an industrial automation communication protocol introduced by Siemens, while Modbus TCP is a variant of the Modbus protocol based on Ethernet. Through this method, the controlled, predictable, and adjustable industrial implementation of the aftercombustion process of high-CO metallurgical flue gas within a confined flue is achieved.

[0062] The above description is merely an explanation of some preferred embodiments of the present invention and the technical principles employed. Those skilled in the art should understand that the scope of the invention as described in the embodiments of the present invention is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in the embodiments of the present invention.

Claims

1. A method for precise oxygen supply and controlled afterburning of high-CO flue gas in metallurgical furnaces, characterized in that, Includes the following steps: S1: Based on the structural and operational parameters of the finite flue, a parameterized model is constructed to describe the aftercombustion process of high-CO metallurgical flue gas. The parameterized model is used to perform functional partitioning, control unit discretization, and parameter definition of the finite flue. S2: Real-time acquisition of flue gas state parameters, oxygen supply state parameters, and wall temperature parameters at the inlet and outlet of the limited flue, and generation of the current operating condition state vector based on the acquired parameters; S3: Based on the parameterized model and the current operating condition vector, calculate the ignition position, combustion length, carbon monoxide conversion rate, outlet residual oxygen index, maximum wall temperature, and deposition risk index of the afterburning process; S4: Based on the ignition position, the combustion length, the carbon monoxide conversion rate, the outlet residual oxygen index, the maximum wall temperature, and the deposition risk index, determine whether the current operating condition is within the controlled afterburning window. The controlled afterburning window simultaneously meets the multi-objective constraints of safe burnout, low residual oxygen, low dilution, and non-adhesion. S5: When it is determined that the current operating condition is outside the controlled afterburning window, a control correction amount is generated based on the rule control strategy or the multi-objective collaborative optimization strategy, and the oxygen supply parameters and flow organization parameters are adjusted according to the control correction amount so that the afterburning process returns to the controlled afterburning window.

2. The method for precise oxygen supply and controlled afterburning of high-CO flue gas in metallurgical furnaces and kilns according to claim 1, characterized in that, The functional zoning of the limited flue in S1 includes: dividing the limited flue along the main flue gas direction into a mixing initiation zone, an ignition formation zone, a main combustion zone, a temperature shaping zone, and a waste heat boiler inlet constraint zone. The discretization of the control unit includes: discretizing the finite flue along the main flue gas direction into N controlled afterburning control units, each of which serves as the minimum addressing unit for afterburning process calculation, risk assessment, and control adjustment, where N is an integer greater than 1; The parameter definition includes: establishing a parameter set for the i-th control unit, the parameter set including the axial distance from the center position of the control unit to the inlet of the finite flue, the axial length of the control unit, the flow cross-sectional area of ​​the control unit, the wetted perimeter of the control unit, the hydraulic diameter of the control unit, the average axial velocity of the flue gas cross section in the control unit, the flue gas pressure in the control unit, the average temperature of the flue gas in the control unit, the volume fraction of carbon monoxide in the control unit, the volume fraction of oxygen in the control unit, the volume fraction of water vapor in the control unit, the flue gas density in the control unit, and the total molar flow rate of the flue gas in the control unit, where i is an integer from 1 to N.

3. The method for precise oxygen supply and controlled afterburning of high-CO flue gas in metallurgical furnaces and kilns according to claim 2, characterized in that, The parameterized model in S1 also includes a set of overall parameterized descriptions for the entire finite flue. The set of overall parameterized descriptions includes the effective length of the finite flue, the characteristic hydraulic diameter of the finite flue, the axial distance from the oxygen injection position to the flue inlet, the position of the flow organization components, the inlet position of the waste heat boiler, the afterburning ignition position, the combustion length of the main combustion zone, the outlet velocity of the oxygen injection jet, the flue gas inlet temperature, the volume fraction of carbon monoxide at the flue gas inlet, the volume fraction of oxygen at the flue gas inlet, and the volume fraction of water vapor at the flue gas inlet.

4. The method for precise oxygen supply and controlled afterburning of high-CO flue gas in metallurgical furnaces and kilns according to claim 1, characterized in that, The parameters collected in real time in S2 include: carbon monoxide concentration at the inlet and outlet, oxygen concentration, flue gas temperature, flue gas velocity, oxygen flow rate, oxygen injection pressure, and oxygen injection location of each oxygen supply branch, location of cyclone separators or flow organization components, and wall temperature near the inlet of the waste heat boiler. The current operating condition state vector includes ignition position, combustion length, carbon monoxide conversion rate, outlet residual oxygen index, flue gas dilution index, maximum wall temperature in the assessment section, maximum deposition risk index in the assessment section, and sampling time of the current control cycle.

5. The method for precise oxygen supply and controlled afterburning of high-CO flue gas in metallurgical furnaces and kilns according to claim 1, characterized in that, The calculation of the ignition position in S3 includes: starting from the oxygen injection position, calculating the cumulative residence time, local oxygen matching coefficient and equivalent ignition delay time for each control unit along the flue gas flow direction, and determining the center position of the first control unit that simultaneously meets the mixing-ignition matching conditions, the temperature after mixing is not less than the afterburning critical ignition temperature and the local oxygen matching coefficient is within the allowable range, as the ignition position. The cumulative residence time is obtained by summing the ratios of the length of each control unit to the average axial velocity of the flue gas; the local oxygen matching coefficient is calculated based on the ratio of the molar flow rate of oxygen that can participate in the carbon monoxide oxidation reaction within the control unit to half of the molar flow rate of carbon monoxide; the equivalent ignition delay time is calculated based on the ignition rate pre-factor, equivalent ignition activation energy, universal gas constant, local temperature after mixing, carbon monoxide molar concentration, oxygen molar concentration, reaction order correction coefficient, humidity correction function, and flow organization correction coefficient.

6. The method for precise oxygen supply and controlled afterburning of high-CO flue gas in metallurgical furnaces and kilns according to claim 5, characterized in that, The calculation of combustion length in S3 includes: starting from the control unit corresponding to the ignition position, calculating the carbon monoxide consumption molar flow rate unit by unit along the flue gas flow direction based on the carbon monoxide oxidation reaction rate, and defining the control unit position where the cumulative carbon monoxide conversion rate first reaches the preset burnout target value as the main combustion end position. The combustion length is calculated based on the difference between the main combustion end position and the ignition position. The formula for calculating the rate of carbon monoxide oxidation reaction is as follows: in, Let be the carbon monoxide oxidation reaction rate within the i-th control unit. Here, ECO is the pre-rate factor for carbon monoxide oxidation, R is the apparent activation energy for carbon monoxide oxidation, and ECO is the universal gas constant. Let be the average temperature of the flue gas in the i-th control unit. and These are the molar concentrations of carbon monoxide and oxygen, respectively. and These are the reaction order correction factors for carbon monoxide and oxygen, respectively. This is a humidity correction function; The formula for calculating the burning length is: in, For the length of combustion, This refers to the position where the main combustion ends. The ignition position is described above.

7. The method for precise oxygen supply and controlled afterburning of high-CO flue gas in metallurgical furnaces and kilns according to claim 1, characterized in that, The calculation of the maximum wall temperature in S3 includes: based on the heat release distribution and flue gas temperature distribution, calculating the wall temperature of each control unit in the waste heat boiler inlet constraint zone through the gas-solid wall heat transfer model, and determining the maximum wall temperature in this zone as the maximum wall temperature. The deposition risk index calculated in S3 includes a weighted average of the wall temperature risk term, the low-velocity deposition risk term, and the particle concentration risk term. The calculation formula for the deposition risk index is as follows: in, As a sedimentation risk indicator, For wall temperature risk items, This is a risk factor for low-velocity deposition. For particulate concentration risk items, These are the weights for the wall temperature risk term, the low-velocity deposition risk term, and the particle concentration risk term, respectively, and they satisfy the following conditions: .

8. The method for precise oxygen supply and controlled afterburning of high-CO flue gas in metallurgical furnaces and kilns according to claim 1, characterized in that, The determination conditions for the controlled afterburning window in S4 include: the sum of the ignition position and the combustion length is less than or equal to the difference between the waste heat boiler inlet position and the safety buffer distance; the carbon monoxide conversion rate is greater than or equal to the preset burnout target value; the outlet residual oxygen index is less than or equal to the allowable upper limit; the maximum wall temperature is less than or equal to the allowable wall temperature; and the deposition risk index is less than or equal to the allowable upper limit. The set of controlled afterburning windows is represented as follows: Where W represents the controlled afterburn window, For the overall parameterized description set, This is the ignition position. For the length of combustion, This is the inlet location of the waste heat boiler. A safety buffer distance is reserved before the inlet of the waste heat boiler. The carbon monoxide conversion rate, The target value for carbon monoxide conversion rate. For export residual oxygen indicators, This is the upper limit for the permitted residual oxygen for export. This represents the maximum wall temperature near the inlet of the waste heat boiler. The allowable temperature of the wall surface. As a sedimentation risk indicator, This represents the upper limit allowed for deposition risk.

9. The method for precise oxygen supply and controlled afterburning of high-CO flue gas in metallurgical furnaces and kilns according to claim 1, characterized in that, The multi-objective collaborative optimization strategy in S5 includes: constructing a comprehensive objective function, and under the constraint of the controlled afterburn window, solving for the optimal control variable vector that minimizes the comprehensive objective function; The formula for calculating the comprehensive objective function is as follows: in, The objective function is a multi-objective collaborative optimization function, where u is a vector of control variables. The ignition position is obtained under the influence of control variables. For the target ignition location, These are the upper and lower limits of the ignition position window, respectively. The combustion length is obtained under the control of variables. For the target burning length, For a limited effective length of flue, The residual oxygen index at the outlet is obtained under the control of variables. The flue gas dilution index is obtained under the control of variables. For the maximum permissible dilution, To determine the maximum deposition risk under the control of variables, To the maximum allowable deposition risk, To obtain the maximum wall temperature under the influence of control variables, The allowable temperature of the wall surface. These are the weighting coefficients for ignition position deviation, combustion length deviation, residual oxygen level, flue gas dilution, deposition risk, and wall temperature exceedance risk, respectively.

10. The method for precise oxygen supply and controlled afterburning of high-CO flue gas in metallurgical furnaces and kilns according to claim 1, characterized in that, The oxygen supply parameters in S5 include the oxygen injection location, oxygen molar flow rate, and oxygen jet outlet velocity of the primary oxygen supply branch, secondary oxygen supply branch, and optional multi-stage oxygen supplementation branch; the flow organization parameters include the location of the hydrocyclone or flow organization component and the flow organization intensity parameters. The change in the control correction amount within adjacent control cycles is not greater than the preset maximum adjustment range; the control correction amount is used to convert into valve opening commands for each level of oxygen supply branch, target displacement commands for oxygen injection nozzle actuators, target angle commands for nozzle angle actuators, and target position commands for cyclone separators or flow organization component actuators.

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