A steel belt drying waste heat recovery method, system, device and medium

Abstract

The application relates to a steel belt drying waste heat recovery method, system, equipment and medium, relates to the steel belt processing technical field, and the method comprises the following steps: according to a steel belt deformation variable, calculating a calendering temperature compensation value required for eliminating steel belt deformation of a tail portion calendering module; according to the real-time hot air temperature and heat loss of a fan, calculating and obtaining a hot air estimated temperature; comparing the hot air estimated temperature and the calendering temperature compensation value, judging and selecting an oven waste heat circulation target; if the hot air estimated temperature is less than the calendering temperature compensation value, circulating hot air of the fan to an oven inlet position; if the hot air estimated temperature is not less than the calendering temperature compensation value, making the fan send hot air with the calendering temperature compensation value to a steel belt inlet position of the tail portion calendering module. The application can realize efficient recycling of drying waste heat, and reduces energy consumption cost.

Description

Technical Field

[0001] This application relates to the field of steel strip processing, and in particular to a method, system, equipment and medium for recovering waste heat from steel strip drying. Background Technology

[0002] The production and processing of stainless steel strip has developed rapidly in recent years. As an important branch of metal products, it is widely used in industries such as industrial manufacturing, construction decoration, and automobile manufacturing. During production, the steel strip undergoes multiple processes including rolling, cleaning, drying, annealing, and pressing to meet the performance and surface quality requirements of different downstream customers. Among these, the drying process is crucial for removing residual moisture or coating solvents from the steel strip surface, providing a dry substrate for subsequent annealing or surface treatment, and is one of the key steps in ensuring the quality of the steel strip.

[0003] In existing drying technologies, drying equipment typically generates high-temperature hot air through gas heating or electric heating to rapidly dry steel strips. After drying, a large amount of high-temperature waste heat, such as the waste hot air at the oven outlet, is mainly treated in two ways: one is to directly discharge it into the external environment through a chimney; the other is to passively cool it using simple heat dissipation devices, such as heat sinks or cooling fans.

[0004] Although existing technologies have made some attempts to recover waste heat from drying processes, significant shortcomings remain: First, waste heat recovery efficiency is low, with most heat energy wasted through emissions or heat dissipation, failing to form a closed-loop cycle with the production process; second, there is a lack of dynamic monitoring and control mechanisms for waste heat temperature, making it impossible to optimize recovery strategies based on real-time operating conditions such as hot air flow and temperature fluctuations; third, heat loss during waste heat transport is not accurately quantified, resulting in a mismatch between the actual usable temperature of the recovered heat and the target demand. These problems not only increase energy consumption costs but also fall short of the sustainable development goals of green manufacturing, necessitating a controllable waste heat recovery technology to improve resource utilization. Summary of the Invention

[0005] The purpose of this application is to provide a method for recovering waste heat from steel strip drying, which can rationally allocate the waste heat circulation path of the drying oven, utilize the waste heat of the drying oven in other processing procedures or recover it back into the drying oven to improve the heating efficiency of the drying oven, realize the efficient recycling of drying waste heat, and reduce energy consumption costs.

[0006] Firstly, this application provides a method for recovering waste heat from steel strip drying, which adopts the following technical solution:

[0007] A method for recovering waste heat from steel strip drying includes:

[0008] The hot air from the oven outlet is sent to the steel strip outlet of the central rolling module and then to the fan.

[0009] Based on the strip deformation at the exit position of the middle rolling module, calculate the rolling temperature compensation value required for the tail rolling module to eliminate strip deformation.

[0010] The estimated hot air temperature is calculated based on the real-time hot air temperature of the fan and the heat loss at the steel strip inlet of the tail rolling module.

[0011] By comparing the predicted hot air temperature with the calendering temperature compensation value, the target for oven waste heat circulation is determined.

[0012] If the estimated hot air temperature is lower than the calendering temperature compensation value, the hot air from the fan will be circulated to the oven inlet.

[0013] If the estimated temperature of the hot air is not less than the rolling temperature compensation value, then the fan will send the hot air at the rolling temperature compensation value to the steel strip inlet of the tail rolling module.

[0014] Before the step of sending the hot air from the oven outlet to the steel strip outlet of the central rolling module and then to the fan, the method further includes:

[0015] To establish an oven temperature stability index, use the following formula:

[0016] S=σ(T) / T_avg,

[0017] Where σ(T) is the temperature standard deviation, and T_avg is the average temperature inside the oven;

[0018] When S is greater than the preset index, if the estimated temperature of the hot air is not less than the rolling temperature compensation value, the fan is allowed to send hot air with the temperature of the rolling temperature compensation value to the steel strip inlet position of the tail rolling module.

[0019] When S is not greater than the preset index, the hot air from the fan is circulated to the oven inlet position, and the heating device of the tail rolling module is adjusted to heat the steel strip so that the temperature at the steel strip inlet position of the tail rolling module reaches the rolling temperature compensation value.

[0020] Before the step of comparing the estimated hot air temperature and the calendering temperature compensation value to determine the target for selecting the oven waste heat circulation, the following steps are included:

[0021] If the initial temperature of the hot air is less than the calendering temperature compensation value, the heat loss in the pipeline is compensated by changing the fan speed, so that the temperature of the hot air when it is transmitted to the steel strip inlet position of the tail calendering module meets the calendering temperature compensation value.

[0022] Determine whether the fan speed for compensating for heat loss in the pipeline exceeds the allowable speed range. If it does not exceed the allowable range, update the estimated hot air temperature to the same value as the rolling temperature compensation value. If it exceeds the allowable range, update the estimated hot air temperature to the same value as the initial hot air temperature.

[0023] By adopting the above technical solution, the rolling temperature compensation value can be dynamically adjusted according to the deformation of the steel strip. The comparison between the predicted temperature of the hot air entering the tail rolling module and the rolling temperature compensation value allows for the selection of a suitable circulation path for the oven's waste heat. When the hot air temperature is sufficient to deform the steel strip, heating and rolling are used to smooth the surface of the steel strip, effectively improving waste heat utilization, enhancing the rolling effect, and improving product quality. Conversely, when the hot air temperature does not reach the rolling temperature compensation value, the hot air is circulated back into the oven, enhancing the oven's heating efficiency and reducing waste in the tail rolling module due to insufficient hot air temperature, thus lowering energy consumption. Furthermore, the actual temperature of the hot air at the steel strip inlet of the tail rolling module is compared with the rolling temperature compensation value. In contrast, when the hot air temperature is insufficient to deform the steel strip, the heat loss of the hot air in the transmission pipeline is compensated by adjusting the fan speed, so that the hot air reaches the calendering temperature compensation value when it is transmitted to the tail calendering module. At the same time, when the fan speed exceeds the allowable range and the fan cannot heat to the calendering temperature compensation value, the hot air is circulated back into the oven, reducing the waste in the tail calendering module due to the hot air temperature not reaching the required steel strip deformation, thus reducing energy consumption. Furthermore, an oven temperature stability index is established, and the hot air delivery path and the heating method of the tail calendering module are dynamically adjusted based on the comparison results with the preset index. Only when the temperature inside the oven is stable is the residual heat circulated to the steel strip inlet of the tail calendering module, so that the steel strip can undergo stable deformation under heating, thereby improving the quality of the steel strip.

[0024] In a preferred embodiment, this application can be further configured such that: the step of calculating the rolling temperature compensation value required to eliminate strip deformation based on the strip deformation at the strip exit position of the central rolling module includes:

[0025] Establish the mapping relationship between the deformation δ of the middle rolling module and the rolling temperature compensation value T using the formula:

[0026] T = δ·E / (α·d²),

[0027] Where E is the elastic modulus of the steel strip, α is the coefficient of thermal expansion, and d is the set thickness of the steel strip;

[0028] When the local deformation of the steel strip exceeds the reference value, the gradient compensation mode is triggered, and the threshold of the rolling temperature compensation value is increased.

[0029] By adopting the above technical solution, a mapping relationship between the deformation of the steel strip and the rolling temperature compensation value is established. Combined with the elastic modulus, thermal expansion coefficient and set thickness of the steel strip, the formula calculation is performed to achieve accurate quantification of the rolling temperature compensation value, thereby effectively improving the accuracy of steel strip deformation correction. When the local deformation of the steel strip is detected to exceed the reference value, the gradient compensation mode is triggered to increase the threshold of the rolling temperature compensation value, further enhancing the adaptability to abnormal deformation of the steel strip and improving the quality stability and consistency of the steel strip during the rolling process.

[0030] In a preferred embodiment, this application may be further configured such that, prior to the step of calculating the estimated hot air temperature based on the real-time hot air temperature of the fan and the heat loss at the steel strip inlet position of the tail rolling module, the method further includes:

[0031] The initial hot air temperature T_out at the actual steel strip inlet position reaching the tail rolling module is calculated using the formula:

[0032] T_out=T_in−ΔT=T_in-(U·A·τ·(T_in−T_out)·(1 / (m·c)),

[0033] Where T_in is the real-time hot air temperature, ΔT is the heat loss of the pipeline, U is the heat transfer coefficient, A is the heat transfer area, τ is the transmission time of the hot air in the pipeline, m is the mass of the hot air, and c is the specific heat capacity of the hot air.

[0034] By adopting the above technical solution, the actual temperature of the hot air at the steel strip inlet of the tail rolling module is calculated, and the temperature change of the hot air after transmission through the pipeline is quantified, thereby providing reference data for the subsequent selection of waste heat recycling targets.

[0035] In a preferred embodiment, this application may be further configured such that, before the step of delivering the hot air from the oven outlet to the steel strip outlet of the central rolling module and then to the fan, the following steps are included:

[0036] Based on the strip deformation detection data from the head rolling module located at the strip inlet of the middle rolling module, the rolling pressure of the middle rolling module is dynamically adjusted using the formula:

[0037] P=P0+ΔP=P0+K∫(δ_max-δ_avg)dt,

[0038] Where P is the rolling pressure value of the middle rolling module, P0 is the pressure value required to roll the steel strip to the set thickness, ΔP is the pressure compensation value, K is the material hardening coefficient, δ_max is the maximum deformation, and δ_avg is the average deformation.

[0039] The deformation of the steel strip at the exit position of the central rolling module is updated in real time.

[0040] By adopting the above technical solution and using the integral control method, the rolling pressure of the middle rolling module is adjusted in real time according to the deformation of the steel strip rolled in the first rolling of the head rolling module. The secondary rolling reduces product defects caused by deformation and reduces the degree of deformation of the steel strip entering the tail rolling module, thereby improving the rolling accuracy and surface quality of the steel strip.

[0041] In a preferred embodiment, this application can be further configured such that: the step of triggering a gradient compensation mode and increasing the threshold of the rolling temperature compensation value when the local deformation of the steel strip exceeds a reference value includes:

[0042] The deformation quantity and degree of the steel strip are obtained within the detection time, and a change curve is generated;

[0043] The fluctuation value of the change curve is calculated. If the fluctuation value exceeds the reference value, the gradient compensation mode is triggered, and the threshold of the rolling temperature compensation value is increased.

[0044] By adopting the above technical solution, comprehensive monitoring of the deformation trend of steel strip is achieved, and the gradient compensation mode is triggered in time when the deformation is abnormal, which effectively avoids product quality problems caused by excessive local deformation. This allows the tail rolling module to be adjusted according to actual needs, thereby improving the accuracy and stability of steel strip deformation repair.

[0045] Secondly, this application provides a waste heat recovery system for steel strip drying based on any of the above methods, employing the following technical solution:

[0046] A waste heat recovery system for steel strip drying includes:

[0047] Heat transfer module: Used to deliver the hot air from the oven outlet to the steel strip outlet of the central calendering module and then to the fan;

[0048] Compensation calculation module: used to calculate the rolling temperature compensation value required for the tail rolling module to eliminate the deformation of the steel strip based on the deformation of the steel strip at the exit position of the middle rolling module;

[0049] Temperature prediction module: used to calculate and obtain the predicted temperature of hot air based on the real-time hot air temperature of the fan and the heat loss at the steel strip inlet of the tail rolling module.

[0050] Target selection module: Used to compare the estimated hot air temperature and the calendering temperature compensation value to determine and select the target for oven waste heat circulation;

[0051] Oven circulation module: If the estimated hot air temperature is lower than the calendering temperature compensation value, the hot air from the fan will be circulated to the oven inlet.

[0052] Calendering circulation module: If the estimated temperature of the hot air is not less than the calendering temperature compensation value, the fan will send hot air at the calendering temperature compensation value to the steel strip inlet position of the tail calendering module.

[0053] Thirdly, this application provides an electronic device that adopts the following technical solution:

[0054] An electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the above-described method for recovering waste heat from steel strip drying.

[0055] Fourthly, this application provides a computer storage medium, as follows:

[0056] A computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the above-described method for recovering waste heat from steel strip drying.

[0057] In summary, this application has the following beneficial technical effects:

[0058] Based on the temperature of the hot air entering the tail rolling module, this application rationally distributes the hot air from the oven outlet to the tail rolling module to improve the effect of eliminating deformation of the steel strip, or directly circulates it back into the oven to increase the heating efficiency of the oven. This achieves efficient recycling of drying waste heat, improves waste heat recovery efficiency, and reduces energy consumption costs. Attached Figure Description

[0059] Figure 1 This is a flowchart of a method for recovering waste heat from drying steel strips in one embodiment of this application.

[0060] Figure 2 This is a flowchart of a sub-step of step S2 in one embodiment of this application.

[0061] Figure 3 This is a flowchart of a sub-step of step S3 in one embodiment of this application.

[0062] Figure 4 This is a flowchart of the steps added before step S4 in one embodiment of this application.

[0063] Figure 5 This is an additional step added before step S1 in one embodiment of this application. Figure 1 .

[0064] Figure 6 This is an additional step added before step S1 in one embodiment of this application. Figure 2 .

[0065] Figure 7 This is a flowchart of a sub-step of step S21 in one embodiment of this application.

[0066] Figure 8 This is a schematic diagram of the structure of a steel strip drying waste heat recovery system according to one embodiment of this application.

[0067] Figure 9 This is a schematic block diagram of an electronic device in one embodiment of this application.

[0068] Attached reference numerals: 1. Heat transfer module; 2. Compensation calculation module; 3. Temperature prediction module; 4. Target selection module; 5. Oven circulation module; 6. Calendering circulation module. Detailed Implementation

[0069] The following is in conjunction with the appendix Figure 1-9 This application will be described in further detail.

[0070] It should be noted that all actions involving the acquisition of data or information in this application are carried out in accordance with the relevant data protection laws and policies of the country where the application is located, and with the authorization of the relevant users.

[0071] refer to Figure 1 A method for recovering waste heat from steel strip drying, specifically including:

[0072] S1. The hot air from the oven outlet is sent to the steel strip outlet of the central rolling module and then to the fan.

[0073] Specifically, hot air first enters the steel strip outlet of the central rolling module to preheat the steel strip. There are no requirements for the hot air temperature; essentially, it maintains the basic thermal state of the steel strip. Since the steel strip has already completed its main forming process at this point, the preheating only needs to prevent microstructural deterioration caused by a sudden drop in material temperature. The residual temperature from the oven's waste heat is sufficient to meet the requirements, which is a passive thermal compensation method.

[0074] S2. Based on the strip deformation at the exit position of the middle rolling module, calculate the rolling temperature compensation value required for the tail rolling module to eliminate strip deformation.

[0075] Specifically, because the steel strip exhibits deformation at both edges, affecting product quality, the temperature compensation in the final rolling module of the rolling process needs to actively intervene in the material's phase transformation process. The deformation of the steel strip directly reflects the internal stress distribution of the material, and the rolling temperature compensation value must precisely match the material's dynamic rheological properties. At this point, the hot air temperature is required to reach the thermodynamic threshold for eliminating residual stress and reconstructing the crystal structure as much as possible.

[0076] S3. Calculate and obtain the estimated hot air temperature based on the real-time hot air temperature of the fan and the heat loss at the steel strip inlet of the tail rolling module.

[0077] Specifically, the hot air predicted temperature is the estimated hot air temperature from the hot air transmission pipe at the steel strip outlet of the middle rolling module to the steel strip inlet of the tail rolling module, calculated based on the heat loss of the hot air in the pipe.

[0078] S4. Compare the predicted hot air temperature with the calendering temperature compensation value to determine the target for oven waste heat circulation.

[0079] Specifically, it is necessary to determine whether the residual heat of the oven can be used in the tail-end calendering process, rationally allocate the destination of the residual heat, maximize the utilization of the oven's residual heat, and improve resource utilization.

[0080] S5. If the estimated hot air temperature is less than the rolling temperature compensation value, the hot air from the fan will be circulated to the oven inlet.

[0081] Specifically, when the hot air reaches the steel strip inlet of the tail-end rolling module, it is sufficient to cause deformation of the steel strip. Heating and rolling are then used to smooth the surface of the steel strip, effectively improving waste heat utilization, enhancing the rolling effect, and improving product quality. Simultaneously, since the steel strip has already been preheated at the outlet of the middle rolling module, when the hot air reaches the rolling temperature compensation value at the tail-end rolling module's inlet, it can be confirmed that the temperature at the tail-end rolling module's inlet is sufficient to cause deformation of the steel strip. This assists the tail-end rolling module in performing a more precise final rolling process to deform the steel strip surface.

[0082] Furthermore, after the hot air enters the steel strip inlet of the tail rolling module, it is recycled back to the oven through the transmission pipeline. The oven then uses the still-heated hot air to heat the air, forming a closed loop of heat circulation.

[0083] S6. If the estimated temperature of the hot air is not less than the rolling temperature compensation value, then the fan will send the hot air at the rolling temperature compensation value to the steel strip inlet position of the tail rolling module.

[0084] Specifically, when the hot air temperature does not reach the rolling temperature compensation value, although there is preheating at the steel strip exit of the middle rolling module, some heat will be lost from the steel strip exit of the middle rolling module to the steel strip inlet of the tail rolling module. At this time, the sum of the estimated hot air temperature and the preheated steel strip temperature may not be able to meet the rolling temperature compensation value. In order to reduce the waste in the tail rolling module due to the hot air temperature not reaching the steel strip deformation requirements, the hot air is circulated back into the oven. The oven uses the returned hot air to continue heating, thereby enhancing the heating efficiency of the oven, forming a closed loop of heat circulation, and reducing the energy consumption of waste heat.

[0085] refer to Figure 2 Furthermore, in one embodiment, step S2 is refined into the following sub-steps:

[0086] S20. Establish the mapping relationship between the deformation δ of the middle rolling module and the rolling temperature compensation value T, using the formula:

[0087] T = δ·E / (α·d²),

[0088] Where E is the elastic modulus of the steel strip, α is the coefficient of thermal expansion, and d is the set thickness of the steel strip.

[0089] Specifically, the local deformation of the steel strip is monitored in real time to obtain δ. The elastic modulus E is the ratio of stress to strain in the elastic deformation stage of a material, i.e., E=ϵ / σ, where σ is the applied stress (unit: Pa) and ϵ is the strain generated. Among various steel strip materials, generally, carbon steel E≈200GPa and stainless steel E≈190−210GPa, but the specific values ​​need to be adjusted according to the steel grade and heat treatment state.

[0090] By establishing a mapping relationship between steel strip deformation and rolling temperature compensation value, and combining the steel strip's elastic modulus, coefficient of thermal expansion, and set thickness for formula calculation, the obtained rolling temperature compensation value is the thermodynamic threshold for achieving the elimination of residual stress and reconstruction of the crystal lattice structure as much as possible. The coefficient of thermal expansion α is a thermodynamic property parameter of a material, describing the sensitivity of the material to dimensional changes when heated. Generally, the coefficient of thermal expansion α of steel... α ≈11·10−6℃ −1 .

[0091] S21. When the local deformation of the steel strip exceeds the reference value, the gradient compensation mode is triggered, and the threshold of the rolling temperature compensation value is increased.

[0092] Specifically, the reference value δ0 = k·d, where k is the deformation coefficient allowed by the process, and in this embodiment, k is taken as 0.01~0.05. When δ>δ0, the gradient compensation mode is triggered.

[0093] In this embodiment, β is the gradient compensation coefficient. When the deformation over-limit ratio δ / δ0≤1.2, the compensation coefficient β=1.1; when 1.2<δ / δ0≤1.5, the compensation coefficient β=1.3; when δ / δ0>1.5, the compensation coefficient β=1.5, and so on, increasing as the deformation over-limit ratio increases.

[0094] The original formula for calculating the rolling temperature compensation value has been adjusted to:

[0095] T = β·(δ·E) / (α·d²).

[0096] Triggering gradient compensation mode to increase the threshold of rolling temperature compensation value can further enhance the adaptability to abnormal deformation of steel strip and improve the quality stability and consistency of steel strip during the rolling process.

[0097] In addition, refer to Figure 3 Furthermore, in one embodiment, step S3 is refined into the following sub-steps:

[0098] S30. Calculate the initial temperature T_out of the hot air at the actual steel strip inlet position reaching the tail rolling module using the formula:

[0099] T_out=T_in−ΔT=T_in-(U·A·τ·(T_in−T_out)·(1 / (m·c)),

[0100] Where T_in is the real-time hot air temperature, ΔT is the heat loss of the pipeline, U is the heat transfer coefficient, A is the heat transfer area, τ is the transmission time of the hot air in the pipeline, m is the mass of the hot air, and c is the specific heat capacity of the hot air.

[0101] Specifically, temperature sensors are installed at the steel strip inlet positions of both the fan and the tail rolling module. These sensors provide accurate temperature data to predict the actual temperature of the hot air arriving at the steel strip inlet position of the tail rolling module, thus providing reference data for selecting the waste heat circulation target in advance.

[0102] In addition, refer to Figure 4 Furthermore, in one embodiment, steps S40 and S41 are added before step S4:

[0103] S40. If the initial temperature of the hot air is less than the rolling temperature compensation value, the heat loss in the pipeline is compensated by changing the fan speed so that the temperature of the hot air when it reaches the steel strip inlet position of the tail rolling module meets the rolling temperature compensation value.

[0104] Specifically, if the initial temperature of the hot air is lower than the rolling temperature compensation value, the initial temperature of the hot air cannot meet the thermodynamic threshold for eliminating residual stress and reconstructing the crystal structure of the steel strip. Therefore, by adjusting the fan speed, the ability to obtain waste heat from the oven is changed, so that the hot air reaches the rolling temperature compensation value when it is transmitted to the tail rolling module.

[0105] S41. Determine whether the fan speed for compensating for pipeline heat loss exceeds the allowable speed range. If it does not exceed the allowable range, update the estimated hot air temperature to the same temperature value as the rolling temperature compensation value. If it exceeds the allowable range, update the estimated hot air temperature to the same temperature value as the initial hot air temperature.

[0106] Specifically, if a change in the fan speed causes the temperature inside the oven to fall short of the required level, it is considered exceeding the permissible speed range. Alternatively, if the fan speed reaches its maximum permissible power, it is also considered exceeding the permissible speed range.

[0107] When the fan speed exceeds the allowable range, the fan cannot heat the hot air to the rolling temperature compensation value. In this case, the hot air is circulated back into the oven, where it is heated to a certain temperature, thus achieving heat recycling and reducing waste at the tail rolling module due to insufficient hot air temperature to meet the steel strip deformation requirements, thereby reducing heat consumption.

[0108] In addition, refer to Figure 5 Furthermore, in one embodiment, steps S10 and S11 are added before step S1:

[0109] S10. Based on the strip deformation detection data from the head rolling module located at the strip inlet of the middle rolling module, dynamically adjust the rolling pressure of the middle rolling module using the formula:

[0110] P=P0+ΔP=P0+K∫(δ_max-δ_avg)dt,

[0111] Where P is the rolling pressure value of the middle rolling module, P0 is the pressure value required to roll the steel strip to the set thickness, ΔP is the pressure compensation value, K is the material hardening coefficient, δ_max is the maximum deformation, and δ_avg is the average deformation.

[0112] Specifically, δ_max represents the maximum deformation, and δ_avg represents the average deformation, which are obtained by setting the sensor array in the middle rolling module. The head rolling module is the first rolling process in the rolling process. After the first rolling, the steel strip enters the middle rolling module for the second rolling. The second rolling reduces product defects caused by deformation and further reduces the deformation of the steel strip.

[0113] S11. Real-time update of the steel strip deformation at the steel strip exit position of the central rolling module.

[0114] Specifically, after dynamically correcting the rolling pressure of the middle rolling module, the strip deformation δ at the strip exit position of the middle rolling module is updated synchronously, thereby adjusting the rolling temperature compensation value T to improve the rolling accuracy and surface quality of the strip.

[0115] In addition, refer to Figure 6 Furthermore, in one embodiment, steps S12, S13, and S14 are added before step S1:

[0116] S12. Establish the oven temperature stability index using the following formula:

[0117] S=σ(T) / T_avg,

[0118] Where σ(T) is the temperature standard deviation, and T_avg is the average temperature inside the oven.

[0119] S13. When S is greater than the preset index, if the estimated temperature of the hot air is not less than the rolling temperature compensation value, the fan is allowed to send hot air with the temperature of the rolling temperature compensation value to the steel strip inlet position of the tail rolling module.

[0120] Specifically, the preset parameters are set by the user. When S is greater than the preset parameter, meaning the temperature inside the oven is stable enough to support normal operation, the waste heat is circulated to the steel strip inlet of the tail rolling module to assist in the third rolling of the steel strip. This ensures stable deformation of the heated steel strip, thereby improving its quality and increasing the utilization rate of waste heat. Furthermore, the hot air returned through the tail rolling module does not affect the normal operation of the oven.

[0121] S14. When S is not greater than the preset index, the hot air from the fan is circulated to the oven inlet position, and the heating device of the tail rolling module is adjusted to heat the steel strip so that the temperature at the steel strip inlet position of the tail rolling module reaches the rolling temperature compensation value.

[0122] Specifically, when S is not greater than the preset target, if the residual heat of the oven is passed through the tail calendering module, which requires dynamic adjustment of the hot air temperature, it may affect the normal operation of the oven. Therefore, directly passing the residual heat through the tail calendering module may affect the normal operation of the oven.

[0123] By adopting the above technical solution, an oven temperature stability index is established, and based on the comparison results with the preset index, the hot air conveying path and the heating method of the tail rolling module are dynamically adjusted. Only when the temperature inside the oven is stable will the residual heat be circulated to the steel strip inlet position of the tail rolling module, so that the deformation of the steel strip under heating can proceed stably, thereby improving the quality of the steel strip.

[0124] In addition, refer to Figure 7Furthermore, in one embodiment, step S21 is refined into the following sub-steps:

[0125] S210. During the detection time, obtain the amount and degree of deformation of the steel strip and generate a change curve.

[0126] Specifically, three sensors are installed at the steel strip exit position of the central rolling module. The center point is recorded at the center line in the width direction of the steel strip; the left point is recorded at 10% of the width from the left edge of the steel strip; and the right point is recorded at 10% of the width from the right edge of the steel strip.

[0127] Furthermore, the deformation of three points is collected in real time at a fixed frequency. Combined with the running speed of the steel belt, the time data is converted into position data to generate lateral (left point, center point, right point) and longitudinal (time-varying) deformation curves.

[0128] S211. Calculate the fluctuation value of the change curve. If the fluctuation value exceeds the reference value, trigger the gradient compensation mode and increase the threshold of the rolling temperature compensation value.

[0129] Specifically, the standard deviation of the three point deformation variables is calculated to measure the difference in lateral deformation; the standard deviation of data from the center point over 10 consecutive seconds is taken to measure the fluctuation over time. A baseline value for the fluctuation is also set. In this embodiment, the baseline value is set as a lateral fluctuation threshold of 0.3% of the steel strip thickness and a longitudinal threshold of 0.5%.

[0130] If the lateral or longitudinal fluctuation exceeds the benchmark value, it is considered abnormal. Lateral exceedance is determined by locating the compensation area based on left / right side data; longitudinal exceedance is determined by expanding the compensation area along the direction of the steel strip's movement.

[0131] Next, temperature compensation is performed according to the calculation formula of the rolling temperature compensation value in the gradient compensation mode, which effectively avoids product quality problems caused by excessive local deformation. This allows the tail rolling module to adjust according to the actual deformation of the steel strip, thereby improving the accuracy and stability of steel strip deformation elimination.

[0132] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0133] This application also provides a waste heat recovery system for steel strip drying, which corresponds one-to-one with the waste heat recovery method for steel strip drying in the embodiments.

[0134] refer to Figure 8A waste heat recovery system for steel strip drying includes: a heat transfer module 1, a compensation calculation module 2, a temperature prediction module 3, a target selection module 4, an oven circulation module 5, and a calendering circulation module 6. Detailed descriptions of each functional module are as follows:

[0135] A waste heat recovery system for steel strip drying includes:

[0136] Heat transfer module 1: Used to send the hot air from the oven outlet to the steel strip outlet of the central rolling module and then to the fan.

[0137] Compensation Calculation Module 2: This module calculates the rolling temperature compensation value required by the tail rolling module to eliminate strip deformation based on the strip deformation at the strip exit position of the middle rolling module.

[0138] Temperature prediction module 3: It is used to calculate and obtain the predicted temperature of hot air based on the real-time hot air temperature of the fan and the heat loss at the steel strip inlet position sent to the tail rolling module.

[0139] Target selection module 4: Used to compare the estimated hot air temperature and the calendering temperature compensation value to determine and select the target for oven waste heat circulation.

[0140] Oven circulation module 5: If the estimated hot air temperature is less than the calendering temperature compensation value, the hot air from the fan will be circulated to the oven inlet.

[0141] 6. Calendering circulation module: If the estimated temperature of the hot air is not less than the calendering temperature compensation value, the fan will send hot air at the calendering temperature compensation value to the steel strip inlet position of the tail calendering module.

[0142] The heat transfer module 1 delivers hot air from the oven outlet to the steel strip outlet of the middle rolling module and then to the fan. From the fan, it waits for the heat circulation path to be determined by the target selection module 4, ensuring that the waste heat from the oven is transferred and circulated effectively. The compensation calculation module 2 dynamically adjusts the required rolling temperature compensation value of the tail rolling module based on the steel strip deformation, improving the accuracy of eliminating steel strip deformation. The temperature prediction module 3, combined with the real-time hot air temperature and heat loss of the fan, calculates the steel strip inlet position where the hot air enters the tail rolling module. The estimated temperature at the time provides a basis for the diversion decision of the subsequent circulation path; the target selection module 4 selects a suitable oven waste heat circulation path by comparing the estimated hot air temperature with the rolling temperature compensation value, thereby improving the utilization efficiency of oven waste heat; the rolling circulation module 5 sends hot air to the steel strip inlet of the tail rolling module when the hot air temperature meets the rolling requirements, using waste heat to assist rolling and improve the flatness and processing quality of the steel strip; while the oven circulation module 6 reintroduces hot air into the oven inlet when the hot air temperature is insufficient, enhancing the oven heating effect and minimizing heat waste. Through the combination of these modules, the utilization rate of oven waste heat is effectively improved, and the steel strip rolling process is optimized by heating the steel strip, reducing energy consumption and improving the surface quality and production stability of the steel strip.

[0143] Specific limitations regarding the waste heat recovery system for steel strip drying can be found in the context of the waste heat recovery method for steel strip drying, and will not be repeated here. Each module in the aforementioned waste heat recovery system for steel strip drying can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in an electronic device, or stored in the memory of the electronic device as software, so that the processor can call and execute the operations corresponding to each module. In one embodiment, an electronic device is provided, which is a user terminal. (Reference) Figure 9 The electronic device includes a processor, memory, network interface, and database connected via a system bus. The processor provides computing and control capabilities. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores the operating system, computer programs, and database. The internal memory provides the environment for the operation of the operating system and computer programs in the non-volatile storage medium. The database stores detection data tables. The network interface is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements a method for recovering waste heat from steel strip drying.

[0144] In one embodiment, an electronic device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to perform the following steps:

[0145] S1. The hot air from the oven outlet is sent to the steel strip outlet of the central rolling module and then to the fan.

[0146] S2. Based on the strip deformation at the exit position of the middle rolling module, calculate the rolling temperature compensation value required for the tail rolling module to eliminate strip deformation.

[0147] S3. Calculate and obtain the estimated hot air temperature based on the real-time hot air temperature of the fan and the heat loss at the steel strip inlet of the tail rolling module.

[0148] S4. Compare the predicted hot air temperature with the calendering temperature compensation value to determine the target for oven waste heat circulation.

[0149] S5. If the estimated hot air temperature is less than the rolling temperature compensation value, the hot air from the fan will be circulated to the oven inlet.

[0150] S6. If the estimated temperature of the hot air is not less than the rolling temperature compensation value, then the fan will send the hot air at the rolling temperature compensation value to the steel strip inlet position of the tail rolling module.

[0151] In one embodiment, the sub-steps of step S2 refinement include:

[0152] S20. Establish the mapping relationship between the deformation δ of the middle rolling module and the rolling temperature compensation value T, using the formula:

[0153] T = δ·E / (α·d²),

[0154] Where E is the elastic modulus of the steel strip, α is the coefficient of thermal expansion, and d is the set thickness of the steel strip.

[0155] S21. When the local deformation of the steel strip exceeds the reference value, the gradient compensation mode is triggered, and the threshold of the rolling temperature compensation value is increased.

[0156] In one embodiment, the refined sub-steps of step S3 include:

[0157] S30. Calculate the initial temperature T_out of the hot air at the actual steel strip inlet position reaching the tail rolling module using the formula:

[0158] T_out=T_in−ΔT=T_in-(U·A·τ·(T_in−T_out)·(1 / (m·c)),

[0159] Where T_in is the real-time hot air temperature, ΔT is the heat loss of the pipeline, U is the heat transfer coefficient, A is the heat transfer area, τ is the transmission time of the hot air in the pipeline, m is the mass of the hot air, and c is the specific heat capacity of the hot air.

[0160] In one embodiment, the additional step before step S4 includes:

[0161] S40. If the initial temperature of the hot air is less than the rolling temperature compensation value, the heat loss in the pipeline is compensated by changing the fan speed so that the temperature of the hot air when it reaches the steel strip inlet position of the tail rolling module meets the rolling temperature compensation value.

[0162] S41. Determine whether the fan speed for compensating for pipeline heat loss exceeds the allowable speed range. If it does not exceed the allowable range, update the estimated hot air temperature to the same temperature value as the rolling temperature compensation value. If it exceeds the allowable range, update the estimated hot air temperature to the same temperature value as the initial hot air temperature.

[0163] In one embodiment, the additional step before step S1 includes:

[0164] S10. Based on the strip deformation detection data from the head rolling module located at the strip inlet of the middle rolling module, dynamically adjust the rolling pressure of the middle rolling module using the formula:

[0165] P=P0+ΔP=P0+K∫(δ_max-δ_avg)dt,

[0166] Where P is the rolling pressure value of the middle rolling module, P0 is the pressure value required to roll the steel strip to the set thickness, ΔP is the pressure compensation value, K is the material hardening coefficient, δ_max is the maximum deformation, and δ_avg is the average deformation.

[0167] S11. Real-time update of the steel strip deformation at the steel strip exit position of the central rolling module.

[0168] In one embodiment, the additional step before step S1 includes:

[0169] S12. Establish the oven temperature stability index using the following formula:

[0170] S=σ(T) / T_avg,

[0171] Where σ(T) is the temperature standard deviation, and T_avg is the average temperature inside the oven.

[0172] S13. When S is greater than the preset index, if the estimated temperature of the hot air is not less than the rolling temperature compensation value, the fan is allowed to send hot air with the temperature of the rolling temperature compensation value to the steel strip inlet position of the tail rolling module.

[0173] S14. When S is not greater than the preset index, the hot air from the fan is circulated to the oven inlet position, and the heating device of the tail rolling module is adjusted to heat the steel strip so that the temperature at the steel strip inlet position of the tail rolling module reaches the rolling temperature compensation value.

[0174] In one embodiment, the sub-steps of step S21 are further refined as follows:

[0175] S210. During the detection time, obtain the amount and degree of deformation of the steel strip and generate a change curve.

[0176] S211. Calculate the fluctuation value of the change curve. If the fluctuation value exceeds the reference value, trigger the gradient compensation mode and increase the threshold of the rolling temperature compensation value.

[0177] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0178] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is used as an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

Claims

1. A method of recovering waste heat from steel strip calendering and drying, characterized by, The method comprises the following steps: sending the hot air at the outlet of the oven to the outlet position of the steel belt of the middle calender module and then to the fan; calculating the calender temperature compensation value required for eliminating the deformation of the steel belt of the tail calender module according to the deformation of the steel belt at the outlet position of the middle calender module; calculating the estimated temperature of the hot air according to the real-time temperature of the hot air of the fan and the heat loss of the hot air sent to the inlet position of the steel belt of the tail calender module; comparing the estimated temperature of the hot air with the calender temperature compensation value to determine the target of the residual heat circulation of the oven; if the estimated temperature of the hot air is less than the calender temperature compensation value, circulating the hot air of the fan to the inlet position of the oven; if the estimated temperature of the hot air is not less than the calender temperature compensation value, sending the hot air with the temperature of the calender temperature compensation value to the inlet position of the steel belt of the tail calender module by the fan; before the step of sending the hot air at the outlet of the oven to the outlet position of the steel belt of the middle calender module and then to the fan, the method further comprises the following steps: establishing an oven temperature stability index by using the formula: S = σ(T) / T_avg, wherein σ(T) is the temperature standard deviation and T_avg is the average temperature in the oven; when S is greater than a preset index, allowing the hot air with the temperature of the calender temperature compensation value to be sent to the inlet position of the steel belt of the tail calender module by the fan when the estimated temperature of the hot air is not less than the calender temperature compensation value; when S is not greater than the preset index, circulating the hot air of the fan to the inlet position of the oven and only adjusting the heating device of the tail calender module to heat the steel belt so that the temperature at the inlet position of the steel belt of the tail calender module reaches the calender temperature compensation value; before the step of comparing the estimated temperature of the hot air with the calender temperature compensation value to determine the target of the residual heat circulation of the oven, the method further comprises the following steps: if the initial temperature of the hot air is less than the calender temperature compensation value, compensating the heat loss of the pipeline by changing the rotating speed of the fan so that the temperature of the hot air transmitted to the inlet position of the steel belt of the tail calender module meets the calender temperature compensation value; determining whether the rotating speed of the fan for compensating the heat loss of the pipeline exceeds the allowed rotating speed range, if not, updating the estimated temperature of the hot air to the same temperature value as the calender temperature compensation value, and if yes, updating the estimated temperature of the hot air to the same temperature value as the initial temperature of the hot air.

2. The method of claim 1, wherein, the step of calculating the calender temperature compensation value required for eliminating the deformation of the steel belt according to the deformation of the steel belt at the outlet position of the middle calender module, comprises the following steps: establishing a mapping relationship between the deformation δ of the middle calender module and the calender temperature compensation value T by using the formula: T = δ·E / (α·d²), wherein E is the elastic modulus of the steel belt, α is the thermal expansion coefficient, and d is the set thickness of the steel belt; when the local deformation of the steel belt is detected to exceed a reference value, triggering a gradient compensation mode and increasing the threshold value of the calender temperature compensation value.

3. The method of claim 2, wherein, before the step of calculating the estimated temperature of the hot air according to the real-time temperature of the hot air of thefan and the heat loss of the hot air sent to the inlet position of the steel belt of thetail calender module, the method further comprises the following steps: calculating the initial temperature T_out of the hot air actually reaching the inlet position of the steel belt of the tail calender module by using the formula: T_out = T_in − ΔT = T_in - (U·A·τ·(T_in−T_out)·(1 / (m· c)), Wherein, T_in is the real-time hot air temperature, ΔT is the pipeline heat loss, U is the heat transfer coefficient, A is the heat transfer area, τ is the hot air transmission time in the pipeline, m is the mass of the hot air, and c is the specific heat capacity of the hot air.

4. The method of claim 1, wherein, Before the step of sending the hot air at the outlet position of the steel belt of the middle calendering module to the fan, the method further comprises: According to the steel belt deformation detection data of the head calendering module arranged at the inlet position of the steel belt of the middle calendering module, dynamically correcting the rolling pressure of the middle calendering module, using the formula: P = P0 + ΔP = P0 + K∫(δ_max-δ_avg)dt, Wherein, P is the rolling pressure value of the middle calendering module, P0 is the pressure value required for calendering the steel belt to the set thickness, ΔP is the pressure compensation value, K is the material hardening coefficient, δ_max is the maximum deformation, and δ_avg is the average deformation; Real-time updating the steel belt deformation at the outlet position of the steel belt of the middle calendering module.

5. The method of claim 2, wherein, The step of triggering the gradient compensation mode and increasing the threshold value of the calendering temperature compensation value when detecting that the local deformation of the steel belt exceeds the reference value comprises: Obtaining the number and degree of deformation of the steel belt within the detection time, and generating a change curve; Calculating the fluctuation value of the change curve, and triggering the gradient compensation mode and increasing the threshold value of the calendering temperature compensation value when the fluctuation value exceeds the reference value.

6. A steel strip calendering and drying waste heat recovery system based on the method of any one of claims 1-5, characterized in that, Comprise: A heat transfer module (1) for sending the hot air at the outlet position of the steel belt of the middle calendering module to the fan; A compensation calculation module (2) for calculating the calendering temperature compensation value required for eliminating the deformation of the steel belt according to the deformation of the steel belt at the outlet position of the steel belt of the middle calendering module; A temperature estimation module (3) for calculating the estimated temperature of the hot air according to the real-time hot air temperature of the fan and the heat loss of the hot air sent to the inlet position of the steel belt of the tail calendering module; A target selection module (4) for comparing the estimated temperature of the hot air and the calendering temperature compensation value to determine the selection of the oven waste heat recycling target; An oven recycling module (5) for recycling the hot air of the fan to the inlet position of the oven if the estimated temperature of the hot air is less than the calendering temperature compensation value; A calendering recycling module (6) for sending the hot air with the calendering temperature compensation value to the inlet position of the steel belt of the tail calendering module if the estimated temperature of the hot air is not less than the calendering temperature compensation value.

7. An electronic device, comprising: The computer program for the steel belt calendering and drying waste heat recovery method according to any one of claims 1-5 is stored on the memory and can be loaded and executed by the processor.

8. A computer-readable storage medium, characterized in that, The computer program for the steel belt calendering and drying waste heat recovery method according to any one of claims 1-5 is stored on the memory and can be loaded and executed by the processor.

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