A heating furnace hearth atmosphere control system

Abstract

This invention discloses a furnace atmosphere control system for a heating furnace, comprising: a data communication module; a billet tracking module for tracking process data from billet entry into the furnace to billet exit; a furnace temperature optimization control model for optimizing and calculating the temperature setpoints of each combustion control section of the heating furnace to achieve the most ideal combustion state; a billet data information database for establishing billet information; and a thermal model for billet temperature calculation. The secondary system of this invention can track each billet in the furnace based on the billet data and equipment operating status signals transmitted from the primary system of the heating furnace. Through the management of different modules, it calculates the optimal temperature setpoints for the combustion control sections and the optimal heating furnace output. Under the conditions of meeting rolling line output and heating quality requirements, it strives to achieve the most accurate billet exit temperature, the smallest cross-sectional temperature difference, the least oxidation loss, and the lowest fuel consumption.

Description

Technical Field

[0001] This invention relates to the field of steel rolling management systems, and more specifically, to a furnace atmosphere control system for a heating furnace. Background Technology

[0002] Currently, in order to meet the ever-increasing production capacity demand of steel rolling, various enterprises have expanded their production capacity without scientific planning. They have not made reasonable optimizations to the furnace temperature settings and fuel consumption of heating furnaces before expanding production, resulting in problems such as inaccurate furnace temperature, large temperature differences across sections, high oxidation loss, and high fuel consumption. There is a lack of truly effective heating furnace management methods. Summary of the Invention

[0003] In view of this, the present invention provides a furnace atmosphere control system for a heating furnace to solve the above problems.

[0004] To solve the above technical problems, the present invention provides a furnace atmosphere control system for a heating furnace, comprising: The data communication module is used to acquire basic data of billets, thermal conditions of the heating furnace, operating status of furnace equipment, and given temperature setpoints for combustion control. The in-furnace billet tracking module is used to track process data from the moment the billet enters the furnace until it exits the furnace. The furnace temperature optimization control model is used to optimize the temperature setpoint of each combustion control section of the furnace based on the different steel grades and specifications of the billets, the distribution of billets in the furnace, and the heating conditions, so that the furnace can obtain the most ideal combustion state. The billet data information database is used to establish billet information, including basic billet data, temperature nodes for determining the thermal model used for temperature calculation, and the initial temperature distribution of the billet. The thermal model for billet temperature calculation is used to periodically calculate the temperature distribution, temperature changes, and specific enthalpy of each billet in the furnace.

[0005] As an optional method, the data communication module is used for data communication with the rolling mill computer, furnace area, and control system's instrument PLC and electrical PLC; its communication content includes: Communication with the heating furnace electrical PLC includes: Content from the heating furnace electrical PLC: walking beam cycle completion signal, steel loading completion signal, steel unloading completion signal, steel loading and exit signal, billet unloading and return signal; The content transmitted to the heating furnace electrical PLC includes: heating completion and steel tapping permission signals; Communication with the heating furnace instrument PLC includes: Content from the heating furnace instrument PLC: furnace temperature measurement value, current furnace temperature setpoint, and heating furnace operating status; The content transmitted to the heating furnace instrument PLC is: the set furnace temperature value.

[0006] As an optional method, the operating mode of the billet tracking module inside the heating furnace is as follows: The system creates a record for each billet in the furnace. These records are arranged in the computer according to the order in which the billets entered the furnace, without any gaps, and move forward as the billets move. When the steel loading is completed, the system obtains the basic information of the billet and creates a new record. When the billet is removed from the furnace, the corresponding billet record is deleted.

[0007] As an optional approach, the furnace temperature optimization control model addresses the situation where the incoming billets are a mixture of hot and cold billets. The intelligent combustion control system dynamically adjusts the furnace temperature setpoint using billet heating weight rules; this includes: When performing furnace temperature setting calculations, the necessary furnace temperature for each billet is first determined. At the same time, the heating weight of each billet is determined by combining the heating weight rules. Then, the necessary furnace temperatures of all billets in each combustion control section are weighted and averaged to finally determine the set furnace temperature value for each combustion control section. The main factors to be considered in the billet weight rules are: steel grade, target temperature, target specifications, and position within the section.

[0008] As an optional approach, the billet data information database can be stored in the following way: When the billet enters the heating furnace, the system must obtain the basic data of the billet, including billet number, billet size, weight, steel grade and target rolling temperature; Based on the characteristics of billet heating, a two-dimensional finite difference model is used to calculate the temperature distribution of the billet. A cross-section is taken along the length direction for calculation, and the temperature of the grid nodes is used to represent the temperature distribution of the billet.

[0009] As an alternative, the thermal model for calculating billet temperature is performed using a two-dimensional finite difference model.

[0010] As an optional approach, a furnace temperature setpoint management module is also included. The purpose of calculating the furnace temperature setpoint is to determine the temperature setpoint of the combustion control section, ensuring that each billet in the control section is heated to the ideal temperature when it reaches the end of the control section, and that the surface temperature of the billet does not exceed the maximum surface temperature limit at any time, and the temperature difference between the surface and the center does not exceed the maximum temperature difference limit. The calculation process includes: Obtain the current thermal conditions of the heating furnace and the billet temperature distribution calculated by the thermal model; Predict the steel tapping rhythm of the heating furnace; Predict the remaining furnace time required for the billet; Predicting the billet tapping temperature: This step uses the same thermal model as the billet temperature calculation for prediction. Determine the optimal furnace temperature setpoint for heating each billet in each combustion control section; Determine the furnace temperature setpoint for each combustion control section; The steel tapping permission judgment determines whether the temperature of the billet to be tapped and the temperature difference between the surface and the center meet the conditions for tapping.

[0011] The beneficial effects of this invention are as follows: The secondary system of this invention can track each billet in the furnace based on the billet data and equipment operation status signals transmitted from the primary system of the heating furnace. Through the management of different modules, it calculates the optimal temperature setting value of the combustion control section and the optimal output of the heating furnace. Under the conditions of meeting the rolling line output and heating quality, it strives to make the billet exit temperature as accurate as possible, the cross-sectional temperature difference as small as possible, the oxidation loss as small as possible, and the fuel consumption as low as possible. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of a two-level system structure provided in an embodiment of the present invention; Figure 2 This is a schematic diagram illustrating the storage of billet information in the billet data information database provided in an embodiment of the present invention. Detailed Implementation

[0013] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to specific embodiments.

[0014] Example Please see Figure 1 This embodiment provides a furnace atmosphere control system for a heating furnace, including: The data communication module is essential for optimizing control. The system needs to exchange data with other computer control systems to obtain basic billet data, furnace thermal conditions, furnace equipment operating status, and the setpoint for combustion control. Therefore, the system requires data communication with the rolling mill computer and the furnace and control systems (instrument PLC and electrical PLC).

[0015] The in-furnace billet tracking module is used to track process data from the moment the billet enters the furnace until it exits the furnace. The furnace temperature optimization control model is used to optimize the temperature setpoint of each combustion control section of the furnace based on the different steel grades and specifications of the billets, the distribution of billets in the furnace, and the heating conditions, so that the furnace can obtain the most ideal combustion state. The billet data information database is used to establish billet information, including basic billet data, temperature nodes for determining the thermal model used for temperature calculation, and the initial temperature distribution of the billet. The thermal model for billet temperature calculation is used to periodically calculate the temperature distribution, temperature changes, and specific enthalpy of each billet in the furnace.

[0016] As an optional method, the data communication module is used for data communication with the rolling mill computer, furnace area, and control system's instrument PLC and electrical PLC; its communication content includes: Communication with the heating furnace electrical PLC includes: Content from the heating furnace electrical PLC: walking beam cycle completion signal, steel loading completion signal, steel unloading completion signal, steel loading and exit signal, billet unloading and return signal; The content transmitted to the heating furnace electrical PLC includes: heating completion and steel tapping permission signals; Communication with the heating furnace instrument PLC includes: Content from the heating furnace instrument PLC: furnace temperature measurement value, current furnace temperature setpoint, and heating furnace operating status; The content transmitted to the heating furnace instrument PLC is: the set furnace temperature value.

[0017] As an optional method, the operating mode of the billet tracking module inside the heating furnace is as follows: The system creates a record for each billet in the furnace. These records are arranged in the computer according to the order in which the billets entered the furnace, without any gaps, and move forward as the billets move. When the steel loading is completed, the system obtains the basic information of the billet and creates a new record. When the billet is removed from the furnace, the corresponding billet record is deleted.

[0018] As an optional approach, the furnace temperature optimization control model addresses the situation where the incoming billets are a mixture of hot and cold billets. The intelligent combustion control system dynamically adjusts the furnace temperature setpoint using billet heating weight rules; this includes: When performing furnace temperature setting calculations, the necessary furnace temperature for each billet is first determined. At the same time, the heating weight of each billet is determined by combining the heating weight rules. Then, the necessary furnace temperatures of all billets in each combustion control section are weighted and averaged to finally determine the set furnace temperature value for each combustion control section. The main factors to be considered in the billet weight rules are: steel grade, target temperature, target specifications, and position within the section.

[0019] As an optional method, please refer to Figure 2 The storage method for the billet data information database is as follows: When the billet enters the heating furnace, the system must obtain basic data of the billet, such as billet number, billet size, weight, steel grade and target rolling temperature.

[0020] Based on the characteristics of billet heating, a two-dimensional finite difference model is used to calculate the temperature distribution of the billet. This embodiment considers that the square billet is heated from all four sides, and a cross-section along the length direction is used for calculation. During the system calculation, the temperature of the grid nodes shown in Figure 9×5 is used to represent the temperature distribution of the billet. The thickness direction indicates the temperature from the top and bottom surfaces to the center of the billet, while the width direction reflects the temperature from one side surface to the center of the billet. As an alternative, thermal models are used to periodically (e.g., every 5 seconds) calculate the temperature distribution, temperature changes, and specific enthalpy of each billet in the furnace.

[0021] The billet temperature is calculated online using a two-dimensional finite difference model. This model illustrates the heat exchange generated by radiation, convection, and conduction within the furnace. The calculation is performed based on the billet dimensions, steel grade data, and billet location stored in the system.

[0022] The thermophysical properties of different steel grades are stored as temperature functions in a steel grade data table within the system. For each node, the online model uses appropriate interpolated values ​​of the required thermophysical properties to calculate the temperature of the current node.

[0023] An important point to note is that all heat exchange calculations within the system use the same thermal module described above, including setpoint calculations, furnace productivity calculations, and offline simulation applications.

[0024] The furnace temperature setpoint management software periodically (e.g., every half minute) calculates to determine the appropriate temperature setpoint for each combustion control section of the furnace.

[0025] The purpose of calculating the furnace temperature setpoint is to determine the temperature setpoint of the combustion control section, ensuring that each billet reaches the ideal temperature at the end of the control section, and that the surface temperature of the billet never exceeds the maximum surface temperature limit, and the temperature difference between the surface and the center never exceeds the maximum temperature difference limit. The calculation process is as follows: Obtain the current thermal conditions of the heating furnace and the billet temperature distribution calculated by the thermal model.

[0026] Predict the steel tapping rhythm of the heating furnace.

[0027] Predict the remaining furnace time required for the billet.

[0028] Predict the tapping temperature of the billet. The same thermal model used for billet temperature calculation is employed for prediction calculation.

[0029] Determine the optimal furnace temperature setting for heating each billet in each combustion control section.

[0030] Determine the furnace temperature setpoint for each combustion control section. The temperature setpoint for a combustion control section should comprehensively consider all billets affected by the furnace temperature of that section, so that these billets can reach the ideal heating condition as much as possible when they exit the furnace.

[0031] The tapping permit is determined by the requirement that the temperature of the billet to be tapped and the temperature difference between the surface and the center meet the tapping conditions.

[0032] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be considered as limitations on the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. For those skilled in the art, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A furnace atmosphere control system for a heating furnace, characterized in that, include: The data communication module is used to acquire basic data of billets, thermal conditions of the heating furnace, operating status of furnace area equipment, and temperature setpoints for given combustion control. The in-furnace billet tracking module is used to track process data from the moment the billet enters the furnace until it exits the furnace. The furnace temperature optimization control model is used to optimize and calculate the temperature setpoint of each combustion control section of the furnace according to the different steel grades and specifications of the billets, the distribution of billets in the furnace and the heating conditions, so that the furnace can obtain the most ideal combustion state. The billet data information database is used to establish billet information, including basic billet data, temperature nodes for determining the thermal model used for temperature calculation, and the initial temperature distribution of the billet. A thermal model for calculating billet temperature is used to periodically calculate the temperature distribution, temperature changes, and special enthalpy of each billet in the furnace. The thermal model is calculated using a two-dimensional finite difference model. The furnace temperature optimization control model is designed for situations where hot and cold billets are mixed in the furnace. The intelligent combustion control system dynamically adjusts the furnace temperature setpoint using billet heating weight rules. This includes: when calculating the furnace temperature setpoint, first determining the necessary furnace temperature for each billet, and then determining the heating weight for each billet based on the heating weight rules. This results in a weighted average of the necessary furnace temperatures for all billets within each combustion control section, ultimately determining the set furnace temperature value for each combustion control section. The main factors to be considered in the billet weight rules are: steel grade, target temperature, target specifications, and position within the section. It also includes a furnace temperature setpoint management module, which periodically calculates and determines the temperature setpoint for each combustion control section of the heating furnace. This ensures that each billet in the control section is heated to the ideal temperature when it reaches the end of its control section, and that the surface temperature of the billet never exceeds the maximum surface temperature limit, and the temperature difference between the surface and the center never exceeds the maximum temperature difference limit. The calculation process includes: obtaining the current thermal conditions of the heating furnace and the billet temperature distribution calculated by the thermal model; predicting the furnace tapping rhythm; predicting the remaining time the billet needs to stay in the furnace; predicting the tapping temperature of the billet, this step uses the same thermal model for billet temperature calculation; determining the optimal furnace temperature setpoint for heating each billet in each combustion control section; determining the furnace temperature setpoint for each combustion control section; and determining whether tapping is permitted, judging whether the temperature of the billet to be tapped and the temperature difference between the surface and the center meet the tapping conditions.

2. The furnace atmosphere control system for a heating furnace according to claim 1, characterized in that, The data communication module is used to communicate with the rolling mill computer, furnace area and control system's instrument PLC and electrical PLC. Its communication content includes: Communication with the heating furnace electrical PLC includes: Content from the heating furnace electrical PLC: walking beam cycle completion signal, steel loading completion signal, steel unloading completion signal, steel loading and exit signal, billet unloading and return signal; The content transmitted to the heating furnace electrical PLC includes: heating completion and steel tapping permission signals; Communication with the heating furnace instrument PLC includes: Content from the heating furnace instrument PLC: furnace temperature measurement value, current furnace temperature setpoint, and heating furnace operating status; The content transmitted to the heating furnace instrument PLC is: the set furnace temperature value.

3. The furnace atmosphere control system for a heating furnace according to claim 1, characterized in that, The operating mode of the billet tracking module inside the heating furnace is as follows: The system creates a record for each billet in the furnace. These records are arranged in the computer according to the order in which the billets entered the furnace, without any gaps, and move forward as the billets move. When the steel loading is completed, the system obtains the basic information of the billet and creates a new record. When the billet is removed from the furnace, the corresponding billet record is deleted.

4. A furnace atmosphere control system for a heating furnace according to claim 1, characterized in that, The billet data information database is stored as follows: when the billet enters the heating furnace, the system must obtain the basic data of the billet, including billet number, billet size, weight, steel grade and target rolling temperature; according to the characteristics of billet heating, a two-dimensional finite difference model is used to calculate the temperature distribution of the billet, and a cross section is taken along the length direction for calculation. The temperature of the grid nodes is used to represent the temperature distribution of the billet during the calculation.

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