Comprehensive optimization method for air-fuel ratio of metallurgical heating furnace based on oxidation burning loss of steel billet

Abstract

The invention discloses a comprehensive optimization method for the air-fuel ratio of a metallurgical heating furnace based on steel billet oxidation burning loss. The method comprises the step of optimizing the air-fuel ratios of a soaking section, a heating section and a preheating section section by section. The optimal air-fuel ratio is determined by monitoring and calculating the oxidation burning loss amount and the gas consumption amount of each section in real time and converting the price of each section. The method comprises the following specific steps: initializing parameters, adjusting the air-fuel ratio, checking boundary conditions, calculating an economic value difference, and adjusting the air-fuel ratio according to a result until the air-fuel ratio is optimal. According to the method, the economic value of each section is maximized, so that the economical efficiency and the efficiency of the whole heating furnace system are remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of heating furnace optimization control, and in particular to a comprehensive optimization method for the air-fuel ratio of a metallurgical heating furnace based on oxidation and burning of steel billets. Background Art

[0002] In the metallurgical production process, the heating furnace is a key heat treatment equipment, and its performance directly affects the quality and production cost of steel. The air-fuel ratio (i.e. the ratio of air to fuel) of the heating furnace is a key control parameter, which directly affects the combustion efficiency and economy of the furnace.

[0003] In the prior art, the air-fuel ratio is usually determined according to the change of oxygen content in the flue gas of the heating furnace. However, the prior art only considers the oxygen content in the flue gas of the heating furnace, but does not consider the change of oxidation and burning loss of the billet caused by the change of the air-fuel ratio, and does not comprehensively consider the comprehensive economic indicators of the heating furnace. Summary of the invention

[0004] Based on this, an embodiment of the present application provides a comprehensive optimization method for the air-fuel ratio of a metallurgical heating furnace based on oxidation and burning of steel billets. It comprehensively considers the oxidation and burning amount of the heating furnace and the fuel consumption, and uses the upper and lower limits of the air-fuel ratio of each section of the heating furnace and the excess air coefficient as boundary conditions. The comprehensive economic indicators of comprehensive fuel consumption and oxidation and burning reduction are used as measurement standards to continuously optimize the most suitable air-fuel ratio of each section of the heating furnace.

[0005] In a first aspect, a comprehensive optimization method for the air-fuel ratio of a metallurgical heating furnace based on oxidation and burning of steel billets is provided, the method comprising:

[0006] Determine the upper and lower limits of the air-fuel ratio and excess air coefficient of each section of the heating furnace as constraints;

[0007] In this way, the air-fuel ratio optimization of the equalizing section, the air-fuel ratio optimization of the heating section, and the air-fuel ratio optimization of the preheating section are carried out to determine the optimal air-fuel ratio for each specific heating section in the optimization process; wherein, the air-fuel ratio optimization of the heating section is carried out according to the air-fuel ratio optimization result of the equalizing section, and the air-fuel ratio optimization of the preheating section is carried out according to the air-fuel ratio optimization result of the heating section.

[0008] Optionally, the air-fuel ratio optimization in the equalizing section is performed, specifically including:

[0009] Collect and initialize necessary parameters;

[0010] The air-fuel ratio of the equalizing section is reduced by setting the corresponding step length;

[0011] Calculate the oxidation loss and gas consumption after the air-fuel ratio in the soaking section is reduced and convert the price;

[0012] Determine whether the economic value difference D is greater than 0 and the excess air coefficient and air-fuel ratio are within the specified range;

[0013] If the conditions are met, continue to reduce the air-fuel ratio of the equalizing section, and adjust it according to the set step size; if the conditions are not met, increase the air-fuel ratio of the equalizing section, and the step size is half of the previous reduction step size;

[0014] Calculate the oxidation loss and gas consumption after the air-fuel ratio is reduced, and perform price conversion. After completing the optimization of the air-fuel ratio in the equalizing section, enter the air-fuel ratio optimization in the heating section.

[0015] Optionally, the necessary parameters are collected and initialized, including the cumulative gas consumption of each heating section, the average oxidation loss of each heating section, the unit price of gas, the unit price of oxidized iron scale, and the weight of the billet.

[0016] Optionally, the oxidation loss and gas consumption after the air-fuel ratio in the soaking section is reduced are calculated and the price is converted, including:

[0017] Economic value difference D = (oxidation and burning amount in the initial soaking section - oxidation and burning amount in the soaking section after the air-fuel ratio is reduced) * billet weight * unit price of oxidized iron scale - (gas consumption at the soaking end - gas consumption in the initial soaking section) * unit price of gas.

[0018] Optionally, the air-fuel ratio optimization of the heating section is performed, specifically including:

[0019] The optimal air-fuel ratio of the equalizing section is used as the starting point for the heating section optimization;

[0020] The air-fuel ratio of the heating section is reduced and the corresponding step length is set for the corresponding section;

[0021] Calculate the oxidation loss and gas consumption after the air-fuel ratio in the heating section is reduced and convert the price;

[0022] Determine whether the economic value difference D1 is greater than 0 and the excess air coefficient and air-fuel ratio are within the specified range;

[0023] If the conditions are met, continue to reduce the air-fuel ratio of the equalizing section, and adjust it according to the set step size; if the conditions are not met, increase the air-fuel ratio of the equalizing section, and the step size is half of the previous reduction step size;

[0024] Calculate the oxidation loss and gas consumption after the air-fuel ratio is reduced, and perform price conversion. After completing the optimization of the air-fuel ratio in the heating section, enter the air-fuel ratio optimization in the preheating section.

[0025] Optionally, the oxidation loss and gas consumption after the air-fuel ratio of the heating section is reduced are calculated and the price is converted, including:

[0026] Economic value difference D1 = oxidation and burning loss in the initial heating stage - oxidation and burning loss in the heating stage after the air-fuel ratio is reduced) * billet weight * unit price of oxidized iron scale - (gas consumption in the heating stage - gas consumption in the initial heating stage) * unit price of gas.

[0027] Optionally, the air-fuel ratio optimization in the preheating stage is performed, specifically including:

[0028] The optimal air-fuel ratio of the heating section is used as the starting point for the preheating section optimization;

[0029] The air-fuel ratio in the preheating stage is reduced by setting the corresponding step length for the corresponding stage;

[0030] Calculate the oxidation loss and gas consumption after the air-fuel ratio in the preheating stage is reduced and convert the price;

[0031] Determine whether the economic value difference D2 is greater than 0 and the excess air coefficient and air-fuel ratio are within the specified range;

[0032] If the conditions are met, continue to reduce the air-fuel ratio of the equalizing section, and adjust it according to the set step size; if the conditions are not met, increase the air-fuel ratio of the equalizing section, and the step size is half of the previous reduction step size;

[0033] Calculate the oxidation loss and gas consumption after the air-fuel ratio is reduced, and perform price conversion to optimize the air-fuel ratio in the preheating stage.

[0034] Optionally, the oxidation loss and gas consumption after the air-fuel ratio in the preheating stage is reduced are calculated and the price is converted, including:

[0035] Economic value difference D2 = (oxidation and burning amount in the initial preheating stage - oxidation and burning amount in the preheating stage after the air-fuel ratio is reduced) * billet weight * unit price of oxidized iron scale - (gas consumption in the preheating stage - gas consumption in the initial preheating stage) * unit price of gas.

[0036] Optionally, the method further comprises:

[0037] Monitor the temperature and redox atmosphere in the furnace to adjust the air-fuel ratio; while maintaining the same furnace temperature, change the combustion atmosphere in the heating furnace from oxidizing to reducing.

[0038] In the second aspect, a comprehensive optimization system for air-fuel ratio of a metallurgical heating furnace based on oxidation and burning of steel billets is provided, the system comprising:

[0039] The constraint module is used to determine the upper and lower limits of the air-fuel ratio and excess air coefficient of each section of the heating furnace as constraint conditions;

[0040] The optimization module is used to optimize the air-fuel ratio of the equalizing section, the air-fuel ratio of the heating section, and the air-fuel ratio of the preheating section, and determine the optimal air-fuel ratio determined for each specific heating section during the optimization process; wherein, the air-fuel ratio of the heating section is optimized based on the optimization result of the equalizing section air-fuel ratio, and the air-fuel ratio of the preheating section is optimized based on the optimization result of the heating section air-fuel ratio.

[0041] The beneficial effects brought by the technical solution provided by the embodiment of the present application include at least:

[0042] (1) The changes in gas volume caused by changes in the air-fuel ratio and changes in oxidation and burning losses are comprehensively considered, with the best economic benefit as the optimization goal.

[0043] (2) According to the causes of oxidation and burning of the billet in the heating furnace, the optimization is sought step by step from the high temperature section to the low temperature section, which can timely reduce the economic losses caused by oxidation and burning. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0045] Figure 1 A flow chart for optimizing the air-fuel ratio in the soaking section provided in an embodiment of the present application;

[0046] Figure 2 A flow chart for optimizing the air-fuel ratio in the heating section provided in an embodiment of the present application;

[0047] Figure 3 A flow chart for optimizing the air-fuel ratio in the preheating stage provided in an embodiment of the present application. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0049] In the description of the present invention, the terms "comprises", "has" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may also include other steps or units that are not explicitly listed but are inherent to these processes, methods, products or apparatuses, or steps or units added based on further optimization schemes conceived by the present invention.

[0050] The present application is applied to optimizing the air-fuel ratio of a heating furnace. It comprehensively considers the oxidation and burning loss and fuel consumption of the heating furnace, takes the upper and lower limits of the air-fuel ratio of each section of the heating furnace and the excess air coefficient as boundary conditions, and uses the comprehensive economic indicators of comprehensive fuel consumption and oxidation and burning loss reduction as the measurement standard to continuously optimize the most suitable air-fuel ratio of each section of the heating furnace.

[0051] (1) The current optimization of the air-fuel ratio of the heating furnace is mainly determined by the change of the oxygen content of the flue gas of the heating furnace;

[0052] (2) The current air-fuel ratio of the heating furnace does not take into account the oxidation and burning of the billet caused by changes in the atmosphere (excess air coefficient) in the heating furnace, especially in the high-temperature section.

[0053] This application comprehensively considers the economic value generated by the changes in the gas consumption of the heating furnace caused by the changes in the air-fuel ratio of the heating furnace and the changes in oxidation and burning, takes the upper and lower limits of the air-fuel ratio and the excess air coefficient of each section of the heating furnace as boundary conditions, and takes the optimal economic value as the goal. By comparing the maximum economic value generated by the changes in the gas volume and the oxidation and burning of the billet, the optimal air-fuel ratio in the heating furnace is guided, and the comprehensive economic value of the system is maximized by continuously optimizing the air-fuel ratio of each heating section of the heating furnace.

[0054] Changes in the air-fuel ratio of the heating furnace will cause changes in the gas flow rate and will also change the atmosphere of the heating furnace (excess air coefficient). When the combustion temperature of each section of the heating furnace remains unchanged, changes in the redox atmosphere in the heating furnace will cause changes in the oxidation and burning of the billet. In the heating furnace, especially in the high-temperature section, as the temperature increases and the redox atmosphere changes, the oxidation and burning of the billet changes exponentially. Changes in oxidation and burning seriously affect the yield of finished products, resulting in excessive losses, increased costs, and reduced product competitiveness. This application mainly focuses on optimizing the air-fuel ratio of each heating section during the heating process of the heating furnace, so as to optimize the comprehensive economic value of the heating furnace.

[0055] Specifically included in this application:

[0056] Determine the upper and lower limits of the air-fuel ratio and excess air coefficient of each section of the heating furnace as constraints; specifically, changes in the air-fuel ratio of each section of the heating furnace will inevitably cause changes in the amount of coal gas in each section, and will also cause changes in oxidation and burning losses; we use the comprehensive economic indicators of the heating furnace as a measurement standard, and the upper and lower limits of the air-fuel ratio and the upper and lower limits of the excess air coefficient as constraints. When the amount of coal gas increases, it will inevitably lead to an increase in the burden of fuel supply. However, the increase in the amount of coal gas will change the combustion atmosphere in the heating furnace from oxidizing to reducing. Under the condition of ensuring the same furnace temperature, the formation of oxidation and burning of the billet in the furnace is mainly determined by the atmosphere in the furnace (excess air coefficient). At the same time, the change of the atmosphere in the furnace from oxidizing to reducing will inevitably lead to a reduction in the amount of oxidation and burning losses. When the economic value generated by the reduction in oxidation and burning losses is greater than the increase in the total price of fuel caused by the increase in the amount of coal gas, such an air-fuel ratio is obviously beneficial to the comprehensive economic indicators of the heating furnace.

[0057] In this way, the air-fuel ratio optimization of the equalizing section, the air-fuel ratio optimization of the heating section, and the air-fuel ratio optimization of the preheating section are carried out to determine the optimal air-fuel ratio for each specific heating section in the optimization process; wherein, the air-fuel ratio optimization of the heating section is carried out according to the air-fuel ratio optimization result of the equalizing section, and the air-fuel ratio optimization of the preheating section is carried out according to the air-fuel ratio optimization result of the heating section.

[0058] 1) Optimizing the air-gas ratio in the heating section

[0059] like Figure 1 , and a flow chart for optimizing the air-fuel ratio in the soaking section is given. The formation of oxidation and burning of the billet in the heating furnace increases exponentially with the increase of the billet temperature in the furnace and the change of the atmosphere in the furnace. Therefore, the time for the billet to enter the high-temperature zone in the heating furnace is generally required to be delayed as much as possible. At the same time, the excess air coefficient in the soaking section is generally less than 1, and the air-fuel ratio is generally small and weakly reducing. Therefore, when optimizing the air-fuel ratio, start from the soaking section of the heating furnace and optimize it section by section. As shown in the figure, the necessary parameters are collected and initialized; specifically, the cumulative gas consumption of each heating section, the average oxidation and burning amount of each heating section, the unit price of gas, the unit price of oxidized iron sheet, and the weight of the billet.

[0060] The corresponding step length is set for the corresponding section when the air-fuel ratio of the equalizing section is reduced; the oxidation and burnout amount and gas consumption after the air-fuel ratio of the equalizing section is reduced are calculated and the price is converted; the economic value difference D = (initial oxidation and burnout amount of the equalizing section - oxidation and burnout amount of the equalizing section after the air-fuel ratio is reduced) * billet weight * unit price of oxidized iron sheet - (gas consumption at the equalizing end - initial gas consumption in the equalizing section) * unit price of gas.

[0061] Determine whether the economic value difference D is greater than 0 and the excess air coefficient and air-fuel ratio are within the specified range;

[0062] If the conditions are met, continue to reduce the air-fuel ratio of the equalizing section, and adjust it according to the set step size; if the conditions are not met, increase the air-fuel ratio of the equalizing section, and the step size is half of the previous reduction step size;

[0063] Calculate the oxidation loss and gas consumption after the air-fuel ratio is reduced, and perform price conversion. After completing the optimization of the air-fuel ratio in the equalizing section, enter the air-fuel ratio optimization in the heating section.

[0064] 2) Optimizing the air-fuel ratio in the heating section

[0065] like Figure 2 , and a flow chart for optimizing the air-fuel ratio in the heating section is given. After the optimization of the air-fuel ratio in the equalizing section of the heating furnace is completed, the air-fuel ratio optimization begins in the heating section until the comprehensive economic indicators of each heating section reach the optimal level.

[0066] The optimal air-fuel ratio of the equalizing section is used as the starting point for the heating section optimization;

[0067] The air-fuel ratio of the heating section is reduced and the corresponding step length is set for the corresponding section;

[0068] Calculate the oxidation and burning amount after the air-fuel ratio in the heating section is reduced, the gas consumption and convert the price; economic value difference D1 = initial oxidation and burning amount in the heating section - oxidation and burning amount in the heating section after the air-fuel ratio is reduced) * billet weight * unit price of oxidized iron sheet - (gas consumption in the heating section - initial gas consumption in the heating section) * unit price of gas.

[0069] Determine whether the economic value difference D1 is greater than 0 and the excess air coefficient and air-fuel ratio are within the specified range;

[0070] If the conditions are met, continue to reduce the air-fuel ratio of the equalizing section, and adjust it according to the set step size; if the conditions are not met, increase the air-fuel ratio of the equalizing section, and the step size is half of the previous reduction step size;

[0071] Calculate the oxidation loss and gas consumption after the air-fuel ratio is reduced, and perform price conversion. After completing the optimization of the air-fuel ratio in the heating section, enter the air-fuel ratio optimization in the preheating section.

[0072] 3) Optimizing the air-fuel ratio in the preheating stage

[0073] like Figure 3 , and the flow chart of air-fuel ratio optimization in the preheating section is given. After the air-fuel ratio optimization in each heating section of the heating furnace is completed, the air-fuel ratio optimization begins in the preheating section until the comprehensive economic indicators of the preheating section reach the optimal level, and the air-fuel ratio optimization ends.

[0074] The optimal air-fuel ratio of the heating section is used as the starting point for the preheating section optimization;

[0075] The air-fuel ratio in the preheating stage is reduced by setting the corresponding step length for the corresponding stage;

[0076] Calculate the oxidation and burning amount after the air-fuel ratio in the preheating stage is reduced, the gas consumption and convert the price; economic value difference D2 = (initial oxidation and burning amount in the preheating stage - oxidation and burning amount in the preheating stage after the air-fuel ratio is reduced) * billet weight * unit price of oxidized iron sheet - (gas consumption in the preheating stage - initial gas consumption in the preheating stage) * unit price of gas.

[0077] Determine whether the economic value difference D2 is greater than 0 and the excess air coefficient and air-fuel ratio are within the specified range;

[0078] If the conditions are met, continue to reduce the air-fuel ratio of the equalizing section, and adjust it according to the set step size; if the conditions are not met, increase the air-fuel ratio of the equalizing section, and the step size is half of the previous reduction step size;

[0079] Calculate the oxidation loss and gas consumption after the air-fuel ratio is reduced, and perform price conversion to optimize the air-fuel ratio in the preheating stage.

[0080] In an optional embodiment of the present application, the method also includes monitoring the temperature and redox atmosphere in the furnace to adjust the air-fuel ratio; while maintaining the same furnace temperature, the combustion atmosphere in the heating furnace is changed from oxidizing to reducing.

[0081] In summary, the innovations of this application include: The optimization of the air-fuel ratio of the heating furnace comprehensively considers the comprehensive economic indicators brought to the system by the change of fuel quantity and the change of oxidation and burning. The optimization of the air-fuel ratio of the heating furnace starts from the soaking stage (taking into full consideration the exponential growth of the billet in the furnace in the high temperature stage) and adopts stage-by-stage optimization, which minimizes the generation of oxidation and burning.

[0082] The embodiment of the present application also provides a comprehensive optimization system for the air-fuel ratio of a metallurgical heating furnace based on oxidation and burning of steel billets, the system comprising:

[0083] The constraint module is used to determine the upper and lower limits of the air-fuel ratio and excess air coefficient of each section of the heating furnace as constraint conditions;

[0084] The optimization module is used to optimize the air-fuel ratio of the equalizing section, the air-fuel ratio of the heating section, and the air-fuel ratio of the preheating section, and determine the optimal air-fuel ratio determined for each specific heating section during the optimization process; wherein, the air-fuel ratio of the heating section is optimized based on the optimization result of the equalizing section air-fuel ratio, and the air-fuel ratio of the preheating section is optimized based on the optimization result of the heating section air-fuel ratio.

[0085] The comprehensive optimization system for the air-fuel ratio of a metallurgical heating furnace based on oxidation and burning of steel billets provided in the embodiment of the present application is used to implement the above-mentioned comprehensive optimization method for the air-fuel ratio of a metallurgical heating furnace based on oxidation and burning of steel billets. For the specific definition of the comprehensive optimization system for the air-fuel ratio of a metallurgical heating furnace based on oxidation and burning of steel billets, please refer to the definition of the comprehensive optimization method for the air-fuel ratio of a metallurgical heating furnace based on oxidation and burning of steel billets in the above text, which will not be repeated here. Each part of the above-mentioned comprehensive optimization system for the air-fuel ratio of a metallurgical heating furnace based on oxidation and burning of steel billets can be fully or partially implemented by software, hardware and a combination thereof. The above-mentioned modules can be embedded in or independent of the processor in the device in the form of hardware, or can be stored in the memory in the device in the form of software, so that the processor can call and execute the operations corresponding to the above-mentioned modules.

[0086] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0087] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A comprehensive optimization method for the air-fuel ratio of a metallurgical heating furnace based on billet oxidation and burning, characterized in that: The method comprises: Determine the upper and lower limits of the air-fuel ratio and excess air coefficient of each section of the heating furnace as constraints; In this way, the air-fuel ratio optimization of the equalizing section, the air-fuel ratio optimization of the heating section, and the air-fuel ratio optimization of the preheating section are carried out to determine the optimal air-fuel ratio for each specific heating section in the optimization process; wherein, the air-fuel ratio optimization of the heating section is carried out according to the air-fuel ratio optimization result of the equalizing section, and the air-fuel ratio optimization of the preheating section is carried out according to the air-fuel ratio optimization result of the heating section.

2. The method according to claim 1, characterized in that Optimize the air-fuel ratio in the equalizing section, including: Collect and initialize necessary parameters; The air-fuel ratio of the equalizing section is reduced by setting the corresponding step length; Calculate the oxidation loss and gas consumption after the air-fuel ratio in the soaking section is reduced and convert the price; Determine whether the economic value difference D is greater than 0 and the excess air coefficient and air-fuel ratio are within the specified range; If the conditions are met, continue to reduce the air-fuel ratio of the equalizing section, and adjust it according to the set step size; if the conditions are not met, increase the air-fuel ratio of the equalizing section, and the step size is half of the previous reduction step size; Calculate the oxidation loss and gas consumption after the air-fuel ratio is reduced, and perform price conversion. After completing the optimization of the air-fuel ratio in the equalizing section, enter the air-fuel ratio optimization in the heating section.

3. The method according to claim 2, characterized in that The necessary parameters are collected and initialized, including the cumulative gas consumption of each heating section, the average oxidation loss of each heating section, the unit price of gas, the unit price of oxidized iron sheet, and the weight of the billet.

4. The method according to claim 2, characterized in that: Calculate the oxidation loss and gas consumption after the air-fuel ratio in the soaking section is reduced and convert the price, including: Economic value difference D = (oxidation and burning amount in the initial soaking section - oxidation and burning amount in the soaking section after the air-fuel ratio is reduced) * billet weight * unit price of oxidized iron scale - (gas consumption at the soaking end - gas consumption in the initial soaking section) * unit price of gas.

5. The method according to claim 1, characterized in that Optimize the air-fuel ratio in the heating section, including: The optimal air-fuel ratio of the equalizing section is used as the starting point for the heating section optimization; The air-fuel ratio of the heating section is reduced and the corresponding step length is set for the corresponding section; Calculate the oxidation loss and gas consumption after the air-fuel ratio in the heating section is reduced and convert the price; Determine whether the economic value difference D1 is greater than 0 and the excess air coefficient and air-fuel ratio are within the specified range; If the conditions are met, continue to reduce the air-fuel ratio of the equalizing section, and adjust it according to the set step size; if the conditions are not met, increase the air-fuel ratio of the equalizing section, and the step size is half of the previous reduction step size; Calculate the oxidation loss and gas consumption after the air-fuel ratio is reduced, and perform price conversion. After completing the optimization of the air-fuel ratio in the heating section, enter the air-fuel ratio optimization in the preheating section.

6. The method according to claim 5, characterized in that Calculate the oxidation loss and gas consumption after the air-fuel ratio in the heating section is reduced and convert the price, including: Economic value difference D1 = oxidation and burning loss in the initial heating stage - oxidation and burning loss in the heating stage after the air-fuel ratio is reduced) * billet weight * unit price of oxidized iron scale - (gas consumption in the heating stage - gas consumption in the initial heating stage) * unit price of gas.

7. The method according to claim 1, characterized in that Optimize the air-fuel ratio in the preheating stage, including: The optimal air-fuel ratio of the heating section is used as the starting point for the preheating section optimization; The air-fuel ratio in the preheating stage is reduced by setting the corresponding step length for the corresponding stage; Calculate the oxidation loss and gas consumption after the air-fuel ratio in the preheating stage is reduced and convert the price; Determine whether the economic value difference D2 is greater than 0 and the excess air coefficient and air-fuel ratio are within the specified range; If the conditions are met, continue to reduce the air-fuel ratio of the equalizing section, and adjust it according to the set step size; if the conditions are not met, increase the air-fuel ratio of the equalizing section, and the step size is half of the previous reduction step size; Calculate the oxidation loss and gas consumption after the air-fuel ratio is reduced, and perform price conversion to optimize the air-fuel ratio in the preheating stage.

8. The method according to claim 7, characterized in that Calculate the oxidation loss and gas consumption after the air-fuel ratio in the preheating stage is reduced and convert the price, including: Economic value difference D2 = (oxidation and burning amount in the initial preheating stage - oxidation and burning amount in the preheating stage after the air-fuel ratio is reduced) * billet weight * unit price of oxidized iron scale - (gas consumption in the preheating stage - gas consumption in the initial preheating stage) * unit price of gas.

9. The method according to claim 1, characterized in that: The method further comprises: Monitor the temperature and redox atmosphere in the furnace to adjust the air-fuel ratio; while maintaining the same furnace temperature, change the combustion atmosphere in the heating furnace from oxidizing to reducing.

10. A comprehensive optimization system for air-fuel ratio of metallurgical heating furnace based on billet oxidation and burning, characterized in that: The system comprises: The constraint module is used to determine the upper and lower limits of the air-fuel ratio and excess air coefficient of each section of the heating furnace as constraint conditions; The optimization module is used to optimize the air-fuel ratio of the equalizing section, the air-fuel ratio of the heating section, and the air-fuel ratio of the preheating section, and determine the optimal air-fuel ratio determined for each specific heating section during the optimization process; wherein, the air-fuel ratio of the heating section is optimized based on the optimization result of the equalizing section air-fuel ratio, and the air-fuel ratio of the preheating section is optimized based on the optimization result of the heating section air-fuel ratio.

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